ES1278681U - Sack or wrapping type packaging devoid of plastic elements with high protection against moisture and water (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Sack or wrapping-type packaging formed by at least two sheets of paper superimposed one on top of the other, whose external sides of said sheets are covered with at least one layer of hydrophobic varnish, characterized in that said varnish is distributed over each one of said sheets of paper with a grammage between approximately 4 g/m2 and approximately 9 g/m2 . (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Sack or wrapping-type packaging devoid of plastic elements with high protection against moisture and water

Technical sector

This utility model refers to a sack or wrapping-type packaging for the transport of materials. In particular, this utility model refers to a sack or wrapping-type packaging to contain or wrap paper, cement or other useful material in different sectors such as food, chemicals or construction, devoid of plastic elements («plastic free ») and with high resistance to humidity and water.

State of the art

At present, for the transport of cement and other similar materials in the construction sector, as well as for the transport of other kinds, for example, in the food, chemical sector and for the transport of minerals, bags made of made of paper and plastic.

In general, the sacks frequent in the art are formed by two superimposed sheets of paper of the type, for example, 80 g / m2, between which a plastic sheet is interposed, usually of high-density polyethylene (HDPE), specifically, with a density between 0.945 and 0.965 g / cm3 and a thickness of, for example, approximately 7 microns.

These bags show considerable resistance to humidity, even if they are kept for a long time in a humid environment.

However, said bags have the defect of containing plastic elements. Taking into account the large number of bags of this type used throughout the world for the transport of various materials, the fact of containing plastic elements constitutes a serious problem from the environmental point of view.

Therefore, the Applicant has considered the practically appreciable advantage of how to efficiently and economically manufacture sacks or wrapping-type packages devoid of plastic for the transport of cement, adhesive and other similar materials, which can also protect from moisture. to the material contained therein.

Summary

In a first aspect, the present utility model refers to a sack or packaging of the wrapping type as indicated in claim 1.

The Applicant of the present application has found with surprise that the practically appreciable advantage noted above can be solved efficiently and reliably by means of a sack or wrapping-type packaging capable of containing paper, cement or other similar material, formed by at least two sheets of paper superimposed one on top of the other, the outer sides of which are coated with at least one layer of hydrophobic varnish .

Furthermore, said varnish is distributed on each of said sheets of paper with a grammage of between approximately 4 g / m2 and approximately 9 g / m2.

With the term "sack", in the present description and in the appended claims, reference is made to a sack, bag or any type of container or roll-wrap type packaging for printing with inks and varnishes, suitable for transporting safely and to fully preserve the material contained therein, said material being in solid, semi-solid, or granulated form, different kinds of goods such as, for example, earth, sand, cement, stucco or other useful material in the construction sector, as well as feed, seeds, food for animals and food for people or other useful material in the food, chemical sector or for the transport of minerals and the like, and said container can adopt the shape determined by the material contained in its entirety .

In particular, the term "wrapping-type packaging" refers to a single sheet of paper or attached to another material, both paper and plastic.

Typical examples of wrapper type packaging are, for example, a wrapper for photocopy paper, for rolls of absorbent paper for use in the kitchen, for cookies, for food products in general and non-food, for sugar sachets and the like.

Thanks to the fact that the hydrophobic varnish is distributed on the outer side / face of the paper sheets that form a sack or a wrapping-type packaging, and not on the inner face of the sack or wrapping-type packaging, the contact between the varnish and the product contained inside the sack or wrapping-type packaging.

This varnish transfers water-repellent characteristics to the paper. This significantly reduces both moisture / water vapor transmission (WVTR) and water absorption (Cobb test).

Indeed, thanks to the application of at least one layer of varnish on the outside of the paper sheets that make up the sack or wrapping-type packaging, the paper does not retain water, but rather slips due to the high surface tension present. on the treated paper.

In this way, a highly hydrophobic surface is obtained in the broadest sense of the term, to indicate the property of not absorbing or retaining water.

Thus, it increases the barrier effect with respect to that obtained by standard plastic bags common in the art, guaranteeing high protection against moisture for the product contained inside the bag or wrapping-type packaging, even in the absence of plastic sheets of polyethylene intermediates in the realization of the bag, and consequently improving the storage life of the product contained inside the bag. In particular, the sack or wrapping-type packaging of the present utility model is devoid of plastic elements ("plastic free"), despite which it maintains high performance in storage against humidity and water.

According to a preferred embodiment, said sack or wrapping-type package is formed by at least three, for example three, four, five or a greater number of sheets of paper superimposed on each other.

According to a preferred embodiment, said hydrophobic varnish is of the water-based wax type, such as, for example, a polymeric wax.

According to a preferred embodiment, said hydrophobic varnish is a mixture containing at least one element of the isothiazol-3-one type, such as, for example, 1,2-benzisothiazol-3 (2H) -one, 5-doro-2-methyl-2H-isothiazol-3-one (CMIT) and / or 2-methyl-2H-isothiazol-3-one, and their mixtures.

According to a preferred embodiment, said hydrophobic varnish has a pH between 8 and 9.

According to a preferred embodiment, said hydrophobic varnish has a relative density of approximately 1 g / cm3 at 20 ° C.

According to a preferred embodiment, said hydrophobic varnish has a viscosity of <2000 mPas, preferably <1500 mPas.

According to a preferred embodiment, said varnish is distributed on each of said sheets by means of a coating process, specifically, an industrial process that comprises the uniform application of said varnish on said sheets, drying by oven, calendering or embossing if applicable and subsequent cooling.

According to a preferred embodiment, said sack is formed by a main lateral external surface and by at least one lower bottom fixed to said main external surface, where each of said main lateral external surface and said lower bottom are formed by al at least two of said sheets of paper superimposed one on another and covered with at least one layer of hydrophobic varnish.

In this way, the bag will appear as if it were made up of a single body.

Preferably, the consistency of the lateral outer surface of the bag allows the bag itself to acquire the shape defined by the mass of the material contained therein.

Preferably, said lower bottom will have a flat, partially rigid surface, to be able to function as a support base for the bag on the ground. In this way, said lower bottom having a substantially flat dimension, it is facilitated to support the bag on the ground, on flat surfaces, in a vertical position when the bag is full or partially full.

In one embodiment, preferably, said sack is also constituted by an upper bottom, substantially analogous to the bottom bottom. In this way it is possible to support the I bag on the ground both using the lower bottom as a support base on the ground and, vice versa, using the upper bottom as said support base. This is particularly useful when the bag to be laid on the ground does not have a part that must be oriented upwards and one that faces upwards.

According to a preferred embodiment, said upper bottom is formed by at least two of said sheets of paper superimposed one on another, covered with at least one layer of hydrophobic varnish.

In an alternative embodiment, the bag of the present utility model is of the type defined as "open-mouthed", where said upper bottom is not present. The sack, in this alternative embodiment, is in fact presented with the upper part of the side surface open so that it can be easily filled. Once the bag has been filled, said opening is closed with a corresponding machine for sealing.

According to a preferred embodiment, the internal sides of said at least two sheets are glued to each other in correspondence with the upper end and the lower end of said sheets, to create a kind of tube inside the bag. .

According to a preferred embodiment, the internal sides of said at least two sheets are glued to each other at points arranged in correspondence with said upper and lower ends.

According to a preferred embodiment, the internal sides of said at least two sheets are glued to one another by means of starch glue or vinyl glue.

According to a preferred embodiment, said paper can be chosen from the group consisting of kraft-type paper, high-porosity kraft-type paper, glossy paper, semi-extensible paper, monolucent paper or a type of single-sided packaging paper. glossy and polished and the other rough, glossy or opaque skateboard, duplex smoothed paper, cardboard and the like.

Preferably, each of said paper sheets of said main lateral external surface of said sack has a grammage per square meter of between about 70 and about 120 g / m2, preferably of about 90 g / m2.

Preferably, said backings have a grammage per square meter of between approximately 60 and approximately 100 g / m2, preferably approximately 90 g / m2.

According to a preferred embodiment, said bag also comprises closure systems along a longitudinal line of the outer lateral surface of the bag that extends substantially from said lower bottom to said upper bottom, where said closure systems They include escape routes to guarantee the exit of the air from the inside of the bag.

In this way, a better total air outlet is obtained from the bag.

According to a preferred embodiment, said bag comprises at least one polyethylene sheet interposed between two of said layers of paper coated with said hydrophobic varnish.

In this way, moisture / water vapor transmission (WVTR) inside the bag is further reduced.

In a second aspect, the present utility model refers to a sack or packaging of the wrapper type as indicated in claim 10.

The Applicant of the present application has indeed found with surprise that the practically appreciable advantage noted above can be solved efficiently and reliably by means of a sack or wrapping-type packaging capable of containing paper, cement or other similar material, formed by a single sheet of paper, optionally combined with at least one other sheet of paper or plastic material, whose outer side of said sack or wrapping-type packaging is coated with at least one layer of hydrophobic varnish with a grammage of between approximately 4 g / m2 and , approximately 9 g / m2.

In this way, reams of paper, rolls of absorbent paper for use in the kitchen, cookies, sugar bags, food products in general and non-food can be wrapped with wrapping-type packaging, even made up of a single sheet of coated paper. with at least one layer of hydrophobic varnish. Said layer of hydrophobic varnish makes it possible to protect the products contained within the wrapping-type packaging from moisture, allowing a long conservation in storage.

Other features and advantages of the present utility model will be better indicated through examination of the following detailed description of the preferred, but not exclusive, embodiments, illustrated for indicative purposes only and not limiting with the aid of the accompanying drawings. In particular, in these drawings:

- Figure 1 is a view of an empty sack, according to an embodiment of the present utility model, in which the lower bottom and the upper bottom folded on the side surface are visible;

- Figure 2 shows schematically how the two sheets of paper that make up the sack are glued to one another;

- Figure 3 shows another embodiment of the bag of the present utility model, in which the escape routes are visible along the longitudinal line;

- Figure 4 shows a side view of Figure 3 in which the escape routes are even more visible along the longitudinal line.

Detailed description

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

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

Example 1 (invention). The bag 1 shown in Figure 1 is formed by a main lateral external surface 2, by a lower bottom 3 and by an upper bottom 4 attached to the main external surface 2, to result in the bag 1 as if it were formed by a single body.

The lower bottom 3 and the upper bottom 4 include a flat, partially rigid surface, to be able to be folded over the lateral surface 2 when the bag is empty, to be able to store the bag while occupying the minimum necessary space and to be able to act as the base of the bag. when it is at least partially filled and placed in an upright position.

Bag 1 is made up of two sheets of paper; in particular, the bag is formed by an external sheet of semi-extensible type paper, with a grammage of approximately 90 g / m2, superimposed on an internal sheet of semi-extensible type paper, also of approximately 90 g / m2. 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.

The inner and outer paper sheets of the lower bottom 3 and the upper bottom 4 each have a grammage of approximately 70 g / m2.

The inner and outer paper sheets, both on the side surface and on the bottoms, are covered by coverage with a layer of hydrophobic polymeric wax-type varnish, with a coverage of approximately 5 g / m2. The hydrophobic varnish used is a mixture containing 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 approximately 8.5, a relative density of approximately 1 g / cm3 at 20 ° C and a viscosity <1,500 mPas.

The inner sides of the two inner and outer paper sheets are glued to each other in correspondence with their upper and lower ends, through a transverse gluing, to create a kind of tube inside the bag (see figure 2) . The gluing between the sheets is carried out by points 7 arranged in correspondence with their upper and lower ends, using starch glue.

The bag 1 is not provided with holes like some conventional bags common in the art.

As shown in Figures 3 and 4, the bag is provided with escape routes 6, arranged along the longitudinal line 5, formed by aeration zones made through the absence of glue at said points, to favor the air outlet from inside the bag.

The bag 1 is filled with cement or other similar material, as indicated above, and then closed in a timely manner according to the traditional methods of filling and closing such types of bags. For example, the cement can be introduced into the bag through an opening made in said lower bottom 3, an opening that is then automatically closed at the end of the bag filling phase, through a particular valve with which said lower bottom is provided 3. The sack, a Once filled and subsequently closed, it is subjected to continuous exposure to water for at least 7 days.

Example 2 (comparison).

As comparison example 2, a bag is taken that differs from the bag of the invention shown in Example 1 by the fact that the two sheets of paper that compose it have not been covered with a layer of hydrophobic varnish.

Tests

Example 1 of the invention and Example 2 for comparison have been subjected to various tests, described below, to verify their properties.

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

Test 2: to determine the water absorption of the paper, the Cobb method described in the European standard EN ISO 535 has been used, using 3 different contact times (60 seconds, 120 seconds, 300 seconds) and expressing the test results in g / m2.

Test 3: to determine the tensile strength properties of the paper sheets after immersion in water (wet strength) the test method described in the ISO 3781 standard has been used, expressing the test results in percentages.

Test 4: to determine reliable values of water vapor transmission (WVT) through the paper sheets, the test method described in the ASTM E96 // E96M-15 procedure E standard has been used, both in the condition standard ambient of 23 ° C and 50% relative humidity as in limit conditions, tropical, of 38 ° C and 90% relative humidity, expressing the test results in g / m2 for 24 hours.

Table 1 below shows the results of the different tests.

Table 1

In Table 1 it can be seen that in sample 1 of the invention, in which two layers of paper have been coated with hydrophobic varnish, in the absence of intermediate plastic layers, the air permeability is 360 times better (test 1 of Gurley) with respect to comparison sample 2. Likewise, sample 1 of the invention has a very low water absorption capacity (test 2 at 60 seconds), approximately 6 times lower than a standard paper, therefore water tends to run off very easily. Even carrying out the same test 2 with other duration times (120 and 300 seconds) it can be observed that sample 1 has a much lower water absorption capacity compared to standard paper (approximately 7 and 8 times lower, respectively). .

In relation to test 3, sample 1 of the invention gives the paper 10% more resistance to humidity, if it is exposed to the elements. In the standard bag, on the other hand, no performance variations are shown.

In relation to test 4, both in the standard environmental condition of 23 ° C and 50% relative humidity and in limit conditions, tropical, of 38 ° C and 90% relative humidity, sample 1 of the invention confers a better Vapor permeability, respectively, 82% and 80% better than standard.

Consequently, the bag of the present utility model, even though it is devoid of intermediate layers of plastic, thanks to the external coating provided by a layer of varnish, offers excellent moisture absorption results, which allows a long conservation in storage of the product contained inside the bag.

Naturally, many modifications and variations of the preferred embodiments described above will be apparent to those skilled in the art, while still remaining within the scope of the present utility model.

For example, it is possible to carry out other embodiments that differ from the one relative to Example 1, seen above, by the fact that a) have three or more sheets of paper (up to five sheets of paper), instead of two , all covered with a layer of varnish on the external side, or b) by the fact that, between the two sheets of paper, a polyethylene sheet is interposed, or even c) by the fact of having, in combination with the two or more varnish-coated paper sheets, an additional sheet of paper to which the varnish layer is not applied on the outer side, with or without the interposition of a polyethylene sheet.

Likewise, the embodiments of the present utility model shown above refer in particular to sacks, but, similarly, other embodiments (not described here in detail) may refer to wrapping-type packaging such as, for example, 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, formed by at least two sheets of paper superimposed one on the other, whose external sides of said Sheets are coated with at least one layer of hydrophobic varnish.

Example 4 (invention).

A wrapper type package for wrapping a ream of paper or biscuits consists of a single sheet of paper with a weight of approximately 90 g / m2. The paper sheet is covered by coverage with a layer of hydrophobic polymeric wax-type varnish, with a coverage of approximately 5 g / m2. The hydrophobic varnish used is a mixture containing 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 approximately 8.5, a relative density of approximately 1 g / cm3 at 20 ° C and a viscosity <1,500 mPas.

Example 5 (comparison).

As comparison example 5, a wrapping-type packaging is taken which differs from that of the invention shown in Example 4 by the fact that the only sheet of paper that composes it has not been covered with a layer of hydrophobic varnish.

Example 4 of the present invention and Comparison Example 5 have been subjected to the same Tests 1-4, previously described, to which samples 1 and 2 seen above were subjected.

In a similar way to that seen in the case of sample 1 (a bag made up of two superimposed sheets of paper), also in the case of sample 4 of the present invention (in which the wrapping-type packaging is made up of a single sheet of paper), the fact that the external surface of the sheet of paper has been covered with a hydrophobic varnish has made it possible to improve the quality of moisture absorption compared to comparison sample 5, in which, by the Otherwise, no hydrophobic varnish coating has been applied.

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

Claims (10)

1. Sack or wrapping-type packaging formed by at least two sheets of paper superimposed one on top of the other, the outer sides of said sheets are covered with at least one layer of hydrophobic varnish, characterized in that said varnish is distributed over each one of said sheets of paper having a grammage between approximately 4 g / m2 and approximately 9 g / m2. 2. Sack or wrapping-type packaging according to claim 1, formed by at least three, such as, for example, three, four, five or a greater number of sheets of paper superimposed one on top of the other. 3. Sack or wrapping-type packaging according to claim 1 or 2, wherein said hydrophobic varnish is of the water-based wax type. 4. Sack or wrapping-type packaging according to any of the preceding claims, formed by a main lateral external surface and by at least one lower bottom fixed to said main external surface, where each one of said main lateral external surface and said bottom The bottom is formed by at least two of said sheets of paper superimposed one on another and covered with at least one layer of hydrophobic varnish. 5. Sack or wrapping-type packaging according to claim 4, wherein said sack is further formed by an upper bottom fixed to said main external surface, where, in addition, said upper bottom is formed by at least two of said sheets of paper superimposed one on another and covered with at least one layer of hydrophobic varnish. 6. Sack or wrapping-type packaging according to any of the preceding claims, the internal sides of said at least two sheets of which are glued to each other in correspondence with the upper end and the lower end of said sheets, to create a kind of tube inside the sac. 7. Sack or wrapping-type packaging according to claim 6, the internal sides of said at least two sheets being glued to each other at points arranged in correspondence with said upper and lower ends. 8 . Sack or wrapping-type packaging according to claim 6 or 7, the inner sides of which said at least two sheets are glued to one another by means of starch glue or vinyl glue. 9 . Sack or wrapping-type packaging according to any of the preceding claims, wherein said sack also comprises closure systems along a longitudinal line of the outer lateral surface of the sack that extends substantially from said lower bottom to said bottom upper, where said closure systems include escape routes to guarantee the exit of air from the internal part of the bag. 10 . Sack or wrapping-type packaging formed by a single sheet of paper, where the external side of said sack or wrapping-type packaging is coated with at least one layer of hydrophobic varnish with a grammage of between approximately 4 g / m2 and, approximately 9 g / m2.