WO2016166777A1

WO2016166777A1 - Water resistant bag

Info

Publication number: WO2016166777A1
Application number: PCT/IT2015/000107
Authority: WO
Inventors: Andrea PIERPAOLI
Original assignee: Fiorini Packaging S.P.A.
Priority date: 2015-04-17
Filing date: 2015-04-17
Publication date: 2016-10-20
Also published as: EP3283385A1

Abstract

The present invention relates to a bag (1) consisting of at least two paper sheets superimposed one each other and at least one polyethylene layer applied to the outermost of these paper sheets,characterized in thatthe polyethylene layer is a low density polyethylene in the range of from about 0.910 to about 0.940 g/cm³and it has a thickness of at least 12 microns. The bag of the present invention is able to allow material, such as cement or the like, contained in it to resist to water and humidity for a prolonged period of time.

Description

Title of the invention

"Water resistant bag"

Text of the description

Field of the invention

The present invention relates to a bag for the transportation of materials. In particular, the present invention relates to a bag for the transportation of cement, or other material useful in the building sector, resistant to moisture and water.

State of the art.

Currently, for the transportation of cement and other similar material in the building sector, paper or plastic bags are used.

Typically, the known in the art bags consist of two stacked paper sheets of, for examples, 80 g/m², onto which a high density polyethylene (HDPE) sheet is applied, i.e. having a density in the range of between 0.945 and 0.965 g/cm³ and a thickness for example of about 7 my (microns).

However, these bags have the defect of not being resistant to moisture and water in a satisfactory manner; in fact, the material contained in such bags tend to degrade when left in a humid environment for a few days.

Therefore, the Applicant has faced the technical problem of how to achieve effective and economic bags for the transportation of cement and other similar material so that such material does not degrade in a humid environment.

Summary of the Invention In a first aspect the present invention relates to a bag such as the one indicated in claim 1.

The Applicant of the present application has in fact surprisingly found that a bag adapted to contain cement, or other similar material, said bag consisting of at least two paper sheets superimposed one each other and at least one polyethylene layer applied to the outermost of these paper sheets, characterized in that the polyethylene layer is a low density polyethylene in the range of from about 0.910 to about 0.940 g/cm³ and it has a thickness of at least 12 microns, is able to allow the material contained in it to resist to water and humidity for a prolonged period of time.

In fact, such a bag, subjected to special high humidity storage conditions, thanks to the presence of such a layer of low density polyethylene (LDPE) and a thickness of at least 12 microns, has been shown to maintain the properties of the material contained in it also after at least 7 days.

By the term "bag", in the present description and in the appended claims it is intended a bag or any container designed to safely transport and intact preserve the material contained in it, this material being of solid, semi-solid, or granular form, such as earth, sand, cement, putty, or other material useful in the building sector, as well as feed, pet food and food for people, or other material useful in the food industry, and the like, and such container being such as to assume the shape determined by the material in its entirety contained at its inside. Preferably, said bag is formed by a main lateral external surface and at least one lower end plate attached to said main external surface, so that the bag results as if it is constituted by a single body.

Preferably, the texture of the lateral external surface of the bag is such as to allow the bag itself to assume the shape defined by the mass of the material contained in it.

Preferably, said lower end plate has a flat surface, partially rigid, such as to act as a support base on the ground for the bag. In this way, by the lower end plate having such a substantially flat dimension, the bag support to the ground on flat surfaces in a vertical position is facilitated when the bag is full, or partially full,.

In one embodiment, preferably, said bag is also constituted by an upper end plate, substantially similar to said lower end plate; in this way it is possible to place the bag on the ground and use either the lower end plate as a support base on the ground, or, vice versa, the upper base as such a support base. This is particularly useful when the bag resting on the ground does not present a part which must be facing upwards and one facing downward.

In an alternative embodiment, the bag of the present invention is of the type defined as having an "open mouth", wherein said upper end plate is not present; in such an alternative embodiment, the bag has in fact its upper part of the lateral surface open so as to be easily filled. Once the bag has been filled, this opening is closed with a special sealing machine. Preferably, both the main lateral external surface of said bag and the lower end plate and the upper end plate, if present, are constituted by two of said paper sheets superimposed one each other, so as to define an internal paper sheet and an external paper sheet, superimposed onto said internal paper sheet.

Preferably, each of said internal and external paper sheets of said main lateral external surface of the bag has a weight per square meter of from about 70 to about 100 g/m², preferably of about 80 g/m²

Preferably, each of said internal and external paper sheets of said lower end plates of the bag has a weight per square meter slightly lower than the weight per square meter of said internal and external paper sheets of said main lateral external surface of the bag.

Preferably, said end plates have a weight per square meter from about 60 to about 80 g/m², preferably about 70 g/m².

Preferably, said low density polyethylene layer applied onto the outermost of said paper sheet, either of said main lateral external surface of said bag or of said upper and lower end plates, has a thickness of at least 15 microns, more preferably of about 20 microns.

Preferably, said low density polyethylene layer has a weight per square meter of from about 20 to about 40 g/m², preferably about 25 g/m². In this way, the bag of the present invention differs from the known in the art bags comprising a high density polyethylene (HDPE) layer having a thickness of about 7 microns.

Preferably, the upper surface of said external paper sheet is printed with ink.

In this way on the upper surface of said external paper sheet is created an ink layer between the external paper sheet and the low density polyethylene layer.

Preferably, said bag further comprises a paint layer applied onto at least one of said paper sheets.

Preferably, said paint is of the type having a high gloss degree, such as the OPV paint produced by Siegwerk, Siegburg, Germany.

In this way, the bag of the present invention is provided with additional protection against atmospheric agents.

In a first embodiment, said paint layer is applied between the ink layer applied between the upper surface of the external paper sheet and the low density polyethylene layer.

In a second embodiment, said paint layer is applied to the inside of the internal paper sheet.

Preferably, said bag includes closure systems to preserve the material contained at its inside and to prevent its accidental leakage.

Preferably, said closure systems include bonding systems along a longitudinal line of the external lateral surface of the bag, such a line substantially extending from said lower end plate to said upper base.

Preferably, said bonding systems are made by means of vinyl based adhesives or glues.

Preferably, said bonding systems comprise escape routes to ensure the air escape from the bag inside. Preferably, said escape routes are constituted by small ventilation areas formed along the longitudinal line thanks to the glue absence at those points.

In this way, such closure systems allow the end user to fill the bag in a simple and effective way.

Preferably, the percentage of low density polyethylene present in the bag of the present invention is lower than 20%, more preferably lower than 15%, of the total weight of the bag.

In this way, the bag of the present invention is realized according to Italian legislation on recyclability.

Further characteristics and advantages of the present invention will become more apparent from an examination of the following detailed description of preferred embodiments, but not exclusive, illustrated only by way of non-limiting example with the support of the attached drawings. In particular, in the drawings:

- Figure 1 is a view of an empty bag according to the present invention, wherein the lower end plate and the upper end plate are folded onto the lateral surface are visible.

Detailed Description The following detailed description refers to particular embodiments of the device of the present invention, without limiting the content.

The bag of the present invention is adapted to contain cement, or other similar material useful in buildings, such as sand, gravel, or other material useful for example in the field of animal feed or the like.

Example 1. In a first embodiment, the bag 1 was made by a main lateral external surface 2, a lower end plate 3 and an upper end plate 4 fixed to the main external surface 2, so as to obtain the bag 1 as if it was constituted by a single body.

The lower end plate 3 and the upper end plate 4 included a flat, partially rigid, surface such as to be folded onto the lateral surface 2 when the bag is empty, in order to occupy the minimum space required when the bag is store, and capable of act as the base of the bag, when it was at least partially filled and placed in a vertical position.

The lateral surface 2 of the bag was closed by means of a vinyl-based glue, along a longitudinal line 5 which extends from the lower end plate 3 to the upper end plate 4. Along this longitudinal line 5 escape routes 6 are present, constituted by ventilation areas obtained by absence of glue at such points, to allow the air escape from the inside of the bag 1. The obtained bag 1 was free of holes as, o the contrary, some conventional known in the art bags are. The bag 1 was made from an external paper sheet overlapping an internal paper sheet; each of such an internal and external paper sheets of the lateral external surface 2 of the bag 1 had a weight per square meter of about 80 g/m², while the internal and external paper sheets of the lower end plate 3 and of the upper end plate 4 had a slightly lower weight per square meter of about 70 g/m²

The upper surface of the external paper sheet was printed, and then turned out to be coated with an ink layer.

Such an external printed sheet was then coated with a low density polyethylene layer of about 0.925 g/cm³, having a thickness of 12 microns and weight per square meter of about 25 g/m².

The weight percentage of low density polyethylene present in total in the bag 1 of the present invention turned out to be of about 14% compared to the total weight of the bag.

This allowed the bag 1 of the present invention to be in compliance with Italian regulations on recycling, which require that the weight percentage of polyethylene must be lower than 20% of the total weight of the bag, allowing to recycle more than 80% of the weight of the bag, made from paper.

The bag 1 was filled with cement, or other similar material as indicated above, and subsequently suitably closed according to the traditional methods of filling and closing such types of bags. For example, the cement was inserted into the bag through an opening formed in the lower end plate 3, the opening being subsequently closed automatically at the end of the bag filling step, through a special valve provided within such a lower end plate 2. The so filled and subsequently closed bag was subjected to continuous exposure to water for at least 7 days. At the end of this period, the bag was opened and the cement contained in it was analyzed, which turned out to be perfectly dry.

Therefore, thanks to the presence of the low density polyethylene layer of about 0.910 to 0.940 g/cm³ having a particular thickness of at least 12 microns, the bag turned out to be able to allow the material contained in it to resist to water and humidity for a prolonged period, while maintaining the properties even after 7 days. On the contrary, a similar result was not obtained by using conventional bags wherein the paper sheets were coated with a layer of about 7 microns of a high density polyethylene (HDPE) of about 0.945 and 0.965 g/cm³.

Example 2. A second sample of bag identical to the one described above in Example 1 was prepared, with the only difference that the thickness of the low density polyethylene layer was 20 microns, rather than 12.

The bag was treated as the one of Example 1 giving even better results of water retention after 7 days.

Example 3 A third sample of bag, identical to the one described above in Example 2 was prepared, with the only difference that in this case the bag 1 also included a layer of the high gloss degree OPV paint available by Siegwerk, Germany, applied between the ink layer applied onto the upper surface of the external paper sheet and the low density polyethylene layer.

Example 4. A fourth sample of bag, identical to the one described above in Example 3 was prepared, with the only difference that in this case the OPV paint layer was applied within the internal paper sheet.

The presence of the paint allowed the bags described in Example 3 and 4, subjected to the same water treatment of the bags described in examples 1 and 2, to obtain additional protection against atmospheric agents when subjected to the Cobb method, related to the surface water absorption determination by means of the paper.

Of course, to those skilled in the art many modifications and variations of the preferred embodiments described above will be evident, still remaining within the scope of the invention.

Accordingly, the present invention is not limited to the preferred embodiments described, illustrated only by way of example and not of limitation, but is defined by the following claims.

Claims

1. Bag consisting of at least two paper sheets superimposed one each other and at least one polyethylene layer applied to the outermost of said paper sheets, characterized in that said polyethylene is a low density polyethylene in the range of from about 0,910 to about 0.940 g/cm³ and that said polyethylene layer has a thickness of at least 12 microns.

2. Bag according to claim 1, consisting of a main lateral external surface and at least one lower end plate attached to said main external surface, wherein each of said main lateral external surface and of the said lower end plate is constituted by said two paper sheets superimposed one each other, so as to define one internal paper sheet and one external paper sheet, superimposed onto said internal paper sheet.

3. Bag according to claim 2, wherein said bag is also constituted by an upper end plate fixed to said main external surface, wherein also said upper end plate is constituted by said two paper sheets superimposed one each other, so as to define one internal paper sheet and one external paper sheet, superimposed onto said internal paper sheet.

4. Bag according to any of claims 1 to 3, wherein each of said internal and external paper sheet of said main lateral external surface has a weight per square meter from about 70 to about 100 g/m², preferably of about 80 g/m², and wherein each of said upper and lower end plates has a weight per square meter from about 60 to about 80 g/m², preferably about 70 g/m².

5. Bag according to any of claims 1 to 4, wherein said layer of low density polyethylene applied to the outermost of said paper sheets of either said main lateral external surface of said bag or of said upper and lower end plates, has a thickness of at least 15 microns, more preferably of about 20 microns.

6. Bag according to any one of claims 1 to 5, wherein the upper surface of said outer paper sheet is printed with ink.

7. Bag according to any of claims 1 to 6, wherein said bag further comprises a paint layer applied between the ink layer applied onto the upper surface of the external paper sheet and the low density polyethylene layer.

8. Bag according to any of claims 1 to 6, wherein said bag further comprises a paint layer applied to the inside of the internal paper sheet.

9. Bag according to any one of claims 1 to 8, wherein said bag further comprises closing systems along a longitudinal line of the external lateral surface of the bag which substantially extends from said lower end plate to said upper end plate, wherein said closing systems include escape routes to ensure the air escape from the inside of the bag.

10. Bag according to any of claims 1 to 9, wherein the percentage of low density polyethylene present in the bag is lower than 20%, more preferably lower than 15%, of the total weight of the bag.