BAG OR BUNDLE-TYPE PACKAGING WITH NO PLASTIC ELEMENTS AND HIGH PROTECTION FROM MOISTURE AND WATER

Abstract

The present utility model refers to a bag or a bundle-type packaging suitable to contain cement or other similar material, consisting of at least one sheet of paper wherein the external sides of said sheets are coated with at least one layer of hydrophobic paint.

This paint transfers water-repellent characteristics to the paper; in this way, both the transmission of moisture/water vapor (WVTR) and the absorption of water (COBB) are significantly reduced.

In fact, thanks to at least one layer of paint applied externally to the sheets of paper that make up the bag, the water is not retained by the paper, but slips away due to the high surface tension present on the treated paper.

The barrier effect is thus increased compared to that obtainable from standard bags known in the art, thus guaranteeing the product contained inside the bag a high protection from humidity, even in the absence of intermediate polythene sheets in the manufacture of the bag and, consequently, improving the shelf life of the product contained inside the bag.

The bag achieves these results even though it has no intermediate plastic layers.

Claims

1. Bag or bundle-type packaging comprising at least two sheets of paper overlapped on each other, wherein the external sides of said sheets are coated with at least one layer of hydrophobic paint, characterized in that said paint is distributed on each of said sheets of paper with a weight in the range of about 4 gr/m.sup.2 to about 9 gr/m.sup.2.

2. Bag or bundle-type packaging according to claim 1, comprising at least three sheets of paper overlapped on each other.

3. Bag or bundle-type packaging according to claim 1, wherein said hydrophobic paint is a water-based.

4. Bag or bundle-type packaging according to claim 1, comprising a main lateral external surface and at least one lower bottom secured to said main external surface, wherein each of said main lateral external surface and said lower bottom comprises at least two of said sheets of paper overlapped on each other coated with at least one layer of hydrophobic paint.

5. Bag or bundle-type packaging according to claim 1, further comprising an upper bottom secured to said main external surface, wherein said upper bottom also comprises at least two of said sheets of paper overlapped on each other with at least one layer of hydrophobic paint.

6. Bag or bundle-type packaging according to claim 1, wherein the internal sides of said at least two sheets are glued to each other at the upper end and the lower end of said sheets so as to create a sort of tube inside the bag.

7. Bag or bundle-type packaging according to claim 6 wherein the internal sides of said at least two sheets are glued to each other in points arranged at said upper and lower ends.

8. Bag or packaging according to claim 6, wherein the internal sides of said at least two sheets are glued to each other by means of starch glue or vinyl glue.

9. Bag or bundle-type packaging according to claim 1, wherein said bag further comprises closure systems along a longitudinal line of the external lateral surface of the bag that extends substantially from said lower bottom to said upper bottom, wherein said systems of closure include escape routes to ensure the escape of air from the inside of the bag.

10. Bag or bundle-type packaging comprising a single sheet of paper, optionally coupled with at least one other sheet of paper or plastic material, wherein the outer side of said bag or bundle-type packaging is coated with at least one layer of hydrophobic paint having a weight in the range from about 4 gr/m.sup.2 to about 9 gr/m.sup.2.

Description

[0045] Further features and advantages of this utility model will be better highlighted by examining the following detailed description of preferred, but not exclusive, embodiments, shown only as an indication and not limitation with the support of the attached drawings. In particular, in such drawings:

[0046] FIG. 1 is a view of an empty bag according to an embodiment of the present utility model, wherein the lower bottom and the upper bottom folded on the lateral surface are visible;

[0047] FIG. 2 schematically shows how the two sheets of paper that make up the bag are glued to each other;

[0048] FIG. 3 shows another embodiment of the bag of the present utility model, wherein the escape routes are visible along the longitudinal line;

[0049] FIG. 4 shows a side view of FIG. 3, wherein the escape routes along the longitudinal line are further visible.

DETAILED DESCRIPTION

[0050] The following detailed description refers to particular embodiments of the device of the present utility model, without limiting its content.

[0051] The bag of this utility model is suitable for containing cement or other similar material useful in the construction or in the food, mineral, chemical sector, such as sand, gravel or other material useful for example in the feed and seeds sector for animals or the like.

[0052] Example 1 (of the present invention). The bag 1 shown in FIG. 1 consists of a main lateral external surface 2, a lower bottom 3 and an upper bottom 4 secured to the main external surface 2, so as to make the bag 1 appear as if it were made up of a sole body.

[0053] The lower bottom 3 and the upper bottom 4 comprise a flat, partially rigid surface, such that it can be folded onto the side surface 2 when the bag is empty, so as to be able to store the bag occupying the minimum necessary space, and so as to be able to act as the base of the bag, when it is at least partially full and placed in a vertical position.

[0054] Bag 1 consists of two sheets of paper; in particular, the bag consists of an outer sheet of semi-extensible paper, having a weight of about 90 gr/m.sup.2, overlapped on an internal sheet of semi-extensible type of paper also having a weight of about 90 gr/m.sup.2. The outer sheet has a width that extends at least 20 mm with respect to the width of the inner sheet, to facilitate longitudinal gluing.

[0055] The inner and outer sheets of paper of the lower bottom 3 and the upper bottom 4 each have a weight slightly of about 70 gr/m.sup.2.

[0056] The internal and external paper sheets both of the side surface and of the bottoms are coated by spreading with a layer of hydrophobic paint of the polymer wax type, with a coverage of about 5 gr/m.sup.2. The hydrophobic paint used is a mixture that contains 1,2-benzisothiazol-3(2H)-one, 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT) and 2-methyl-2H-isothiazol-1-one, with a pH of about 8.5, a relative density of about 1 g/cm.sup.3 at 20° C. and a viscosity <1,500 mPas.

[0057] The internal sides of the two internal and external sheets of paper are glued to each other at their upper and lower ends by means of a transverse gluing, so as to create a sort of tube inside the bag (see FIG. 2). The gluing between the sheets takes place by points 7 arranged at their upper and lower ends, using starch glue.

[0058] The bag 1 is not provided with holes like some conventional bags known in the art.

[0059] As shown in FIGS. 3 and 4, the bag is also equipped with escape routes 6, arranged along the longitudinal line 5, consisting of aeration zones created by the absence of glue in these points, to facilitate the escape of air from the inside the bag.

[0060] The bag 1 is filled with cement or other similar material as indicated above, and subsequently suitably closed according to the traditional methods of filling and closing these types of bags. For example, the cement can be inserted inside the bag through an opening obtained in this lower bottom 3, an opening that is subsequently closed automatically at the end of the filling phase of the bag, by means of a particular valve with which this lower bottom 2 is provided. The bag thus filled and then closed is subjected to continuous exposure to water for at least 7 days.

Example 2 (Comparison)

[0061] As a comparison example 2, a bag is taken and differs from the bag of the invention shown in Example 1 in that the two sheets of paper that compose it have not been coated with a layer of hydrophobic paint.

[0062] Test

[0063] Example 1 of the present invention and Example 2 of comparison have been subjected to various tests described below to verify their properties.

[0064] Test 1: the Gurley method was used, as described in ISO 5636-5 standard to determine the air permeability of paper sheets, with air permeability between 0.1 μm/(Pa.Math.s) and 100 μm/(Pa.Math.s), expressing the test results in seconds.

[0065] Test 2: the Cobb method described in the European EN ISO 535 standard was used to determine the water absorption of paper, using 3 different contact times (60 seconds, 120 seconds, 300 seconds) and expressing the test results in g/m.sup.2.

[0066] Test 3: the test method described in ISO 3781 standards was used to determine the tensile strength properties of the paper sheets after immersion in water (wet strength), expressing the test results as a percentage.

[0067] Test 4: the test method described in ASTM E96//E96M-15 standards, procedure E, was used to determine reliable values of water vapor transmission (WVT) through the paper sheets, both in the standard environmental condition of 23° C. and 50% relative humidity and in extreme tropical conditions of 38° C. and 90% relative humidity, expressing the test results g/m.sup.2 for 24 hours.

[0068] Table 1 below shows the results of the various tests.

TABLE-US-00001 TABLE 1 Test 4 Test 4 Test 2 Test 2 Test 2 23° C. 38° C. Test 1 60 sec. 120 sec 300 sec Test 3 50% RH 90% RH Sample Structure sec. m.sup.2 m.sup.2 m.sup.2 % m.sup.2 m.sup.2 1 2 sheets + 7,200 4.7 5.5 5.6 10% 115 735-757 invention paint 2 2 sheets 20 30.6 37.5 43.7 = 578-740 4111-4574 comparison with no paint Result 1/2 360 1/6 1/7 1/8 +10% 82% 80%

[0069] From Table 1 it can be seen that sample 1 of the present invention, wherein the two paper layers have been coated with hydrophobic paint, in the absence of intermediate plastic layers, improves air permeability by 360 times (Gurley test 1) compared to comparison sample 2. Furthermore, the sample 1 of the invention has a very low ability to absorb water (test 2 at 60 seconds), about 6 times less than a standard paper, so the water tends to slide off very easily. Even carrying out the same test 2 with other duration times (120 and 300 seconds), it can be seen that sample 1 has a much lower capacity to absorb water than a standard paper (about 7 and 8 times less, respectively).

[0070] With reference to test 3, sample 1 of the invention gives the paper 10% more resistance to damp, in case it is exposed to the bad weather. In the standard bag, on the other hand, there are no variations in yield.

[0071] With reference to test 4, both in standard environmental conditions of 23° C. and 50% of relative humidity and in extreme tropical conditions of 38° C. and 90% of relative humidity, the sample 1 of the invention grants a better vapor permeability of 82% and 80%, respectively, compared to the standard.

[0072] Therefore, the bag of the present utility model, despite being devoid of intermediate plastic layers, thanks to the external coating provided by a layer of paint, provides excellent moisture absorption results, which allows a long shelf life of the product contained in the inside the bag.

[0073] Naturally, many modifications and changes of the preferred embodiments described above will be evident to those skilled in the art, still remaining within the scope of the present utility model.

[0074] For example, it is possible to implement other embodiments that differ from that of Example 1 seen above, due to the fact a) of having three or more sheets of paper (up to five sheets of paper), instead of two, all coated with a layer of paint on the external side, or b) due to the fact that a polyethylene sheet is interposed between the two sheets of paper, or c) due to the fact to have, in addition to the two or more paper sheets coated with paint, an additional sheet of paper to which the paint layer is not applied on the external side, with or without the interposition of a polyethylene sheet.

[0075] Furthermore, the embodiments of the present utility model shown above refer in particular to bags, but, similarly, other embodiments (not described in detail herein) can refer to bundle-type packaging, such as packaging for reams of paper or packaging for food or other food products or useful in the kitchen, without departing from the scope of protection of this utility model, consisting of at least two sheets of paper overlapped on each other, wherein the outer sides of said sheets are coated with at least one layer of hydrophobic paint

Example 4 (Invention)

[0076] A bundle type packaging for wrapping a ream of paper or biscuits consists of a single sheet of paper having a weight of about 90 gr/m.sup.2. The paper sheet is coated by spreading with a layer of hydrophobic paint of the polymer wax type, with a coverage of about 5 gr/m.sup.2. The hydrophobic paint used is a mixture that contains 1,2-benzisothiazol-3(2H)-one, 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT) and 2-methyl-2H-isothiazol-3-one, with a pH of about 8.5, a relative density of about 1 g/cm.sup.3 at 20° C. and a viscosity <1,500 mPas.

Example 5 (Comparison)

[0077] As a comparison example 5, a bundle-type packaging is taken and differs from that of the invention shown in Example 4 due to the fact that the single sheet of paper that composes it has not been coated with a layer of hydrophobic paint.

[0078] Example 4 of the present invention and Example 5 for comparison were subjected to the same Tests 1-4 described above to which the samples 1 and 2 seen above were subjected.

[0079] Similarly to what has been seen in the case of sample 1 (a bag consisting of two overlapped sheets of paper), also in the case of sample 4 of the present invention (wherein the bundle-type packaging consists of a single sheet of paper), the fact that the external surface of the paper sheet has been coated with a hydrophobic paint has allowed to improve the moisture absorption qualities, compared to the comparison sample 5 on which, on the contrary, no coating with hydrophobic paint has been applied.

[0080] Therefore, the present utility model is not limited to the preferred embodiments described, shown only by way of example and not limited to, but is defined by the claims below.