CELLULOSIC LAMINAR ELEMENT, METHOD FOR OBTAINING SAID ELEMENT AND RECEPTACLE MADE USING SAID CELLULOSIC LAMINAR ELEMENT

Abstract

The present invention relates to a method for producing a coated cellulosic laminar element for disposable food and/or drinks service packaging and containers, comprising the following steps: (a) performing a first application of an aqueous dispersion of an ethylene compound and an acrylic compound on a single side of the cellulosic laminar element; (b) drying the dispersion applied in a); (c) performing, after the drying, a second application of the ethylene compound and acrylic compound to the ethylene compound and acrylic compound applied in a) on the same side; (d) drying the dispersion applied in c). The present invention also relates to a cellulosic laminar element and to a disposable foods and/or drinks service packaging and containers obtained by means of the method of the present invention.

Claims

1. A method for producing a coated cellulosic laminar element for disposable food and/or drinks service packaging and containers, the method comprising: a) Performing a first application of an aqueous dispersion of an ethylene compound and an acrylic compound on a single side of the cellulosic laminar element; b) Drying the dispersion applied in a); c) Performing, after the drying, a second application of the ethylene compound and acrylic compound to the ethylene compound and acrylic compound applied in a) on the same side; d) Drying the dispersion applied in c).

2. The method according to claim 1, wherein the acrylic compound is selected from the group which contains acrylic acid, acrylic styrenated and a combination thereof.

3. The method according to claim 1, wherein, prior to step a), a precoating of a binder and/or a pigment is applied to one side of the cellulosic laminar element.

4. The method according to claim 1 wherein, prior to step a), a precoating of a binder and/or a pigment is applied to both sides of the cellulosic laminar element.

5. The method according to claim 1, wherein drying is carried out following the application of the precoating.

6. The method according to claim 1, wherein the ethylene compound and acrylic compound aqueous dispersion contains at least 25% solids.

7. The method according to claim 1, wherein the ethylene compound and acrylic compound aqueous dispersion contains less than 60% solids.

8. The method according to claim 1, wherein the drying is carried out by means of infrared radiation and drying in a hot-air hood.

9. The method according to claim 1, wherein the temperature of the ethylene compound and acrylic compound layer during the drying lower than 70° C.

10. A cellulosic laminar element for disposable food and/or drinks service packaging and containers, comprising, on one of its sides, a coating having a polymer composition for providing the coating with barrier and heat-sealability properties, wherein the coating consists of a single layer, the polymer composition consisting of an ethylene compound and acrylic compound.

11. The cellulosic laminar element for disposable food and/or drinks service packaging and containers according to claim 10, wherein said cellulosic laminar element is obtained by means of the method comprising: a) Performing a first application of an aqueous dispersion of an ethylene compound and an acrylic compound on a single side of the cellulosic laminar element; b) Drying the dispersion applied in a); c) Performing, after the drying, a second application of the ethylene compound and acrylic compound to the ethylene compound and acrylic compound applied in a) on the same side; d) Drying the dispersion applied in c).

12. The cellulosic laminar element for disposable food and/or drinks service packaging and containers according to claim 10, wherein the grammage of the ethylene compound and acrylic compound is between 2 and 12 g/m.sup.2.

13. The cellulosic laminar element for disposable food and/or drinks service packaging and containers according to claim 10, wherein the grammage of the ethylene compound and acrylic compound is between 9 and 10 g/m.sup.2.

14. The cellulosic laminar element for disposable food and/or drinks service packaging and containers according to claim 10, wherein said cellulosic laminar element has said coating layer on one side only.

15. The cellulosic laminar element for disposable food and/or drinks service packaging and containers according to claim 10, wherein the side to which the coating is not applied has only a starch precoating.

16. A receptacle made of a cellulosic laminar material, comprising a first laminar piece, which forms a side wall of the receptacle, and a second laminar piece, which forms a bottom of the receptacle, wherein the first and second piece are both made from the cellulosic laminar element according to claim 10, said first and second pieces being interconnected by heat-sealing therebetween, in such a way that said coating covers the shaped internal walls of said receptacle and the first piece is closed by contact between two of its ends along a generatrix of the side wall of the geometric figure defining the receptacle, the join being sealed by means of heat-sealing between one side of the laminar element forming the piece and the other side, and the second laminar piece, which forms the bottom of the receptacle, being sealed by means of heat-sealing with the first laminar piece forming the side wall of the receptacle.

Description

[0051] A number of embodiments of the present invention will be described in more detail below with reference to the accompanying schematic drawings, in which:

[0052] FIG. 1 is a flow diagram illustrating an embodiment of the method of the present invention.

[0053] FIG. 2 is a cross section through a preferred embodiment of the coated cellulosic laminar element.

[0054] FIG. 3 is a front view of the receptacle obtained by means of the present invention.

[0055] FIG. 4 is a longitudinal section through the receptacle of the present invention.

[0056] FIG. 1 is a schematic illustration by way of a flow diagram in accordance with an embodiment of the method of the present invention, shown by way of example. In a first step, a cellulosic laminar element 4 obtained from high-quality lignin-free chemical pulp compatible with recycling technologies optionally receives a precoating 1, which comprises a binder and/or a pigment, on one of its sides, followed by subsequent drying. Next, a first application of an aqueous dispersion 2′ of an ethylene compound and an acrylic compound is performed on said side of the cellulosic laminar element. In a following step 3, said dispersion is dried by means of infrared radiation and drying in a hot-air hood. A second dispersion 2″ of the same ethylene compound and acrylic compound is applied to the same side. In a subsequent step 3′, the dispersion is dried again. Lastly, a coated cellulosic laminar element 4′ is obtained.

[0057] In the above-described embodiment, steps 1 and 2′ are optionally carried out in a paper machine whilst steps 3, 2″ and 3′ are carried out in a covering machine, which may be located outside of the production line for the cellulosic laminar element.

[0058] FIG. 2 shows the structure resulting from the method of the present invention. The coated cellulosic laminar element 4′ has a single layer of coating 2 with an ethylene and acrylic compounds, said layer being obtained by two applications with intermediate drying.

[0059] FIG. 3 shows a receptacle 7 comprising a laminar piece that forms a side wall of the receptacle 5. The ends of said piece are heat-sealed together along a generatrix 8, in such a way that said coating covers the side walls of said receptacle. The laminar pieces have a coating according to the present invention on one or both sides (not shown).

[0060] In FIG. 4, it can be seen that the receptacle 7 comprises a first laminar piece, which forms a side wall 5 of the receptacle, and a second laminar piece, which forms a bottom 6 of the receptacle, the first and second pieces comprising a cellulosic laminar element 4 and an ethylene compound and acrylic compound coating 2. The seal between the two pieces is brought about by means of clamps and the application of hot air to heat the coating above the fusing temperature. The receptacle 7 has no coating on the external part of the bottom 6 of the receptacle.

[0061] In addition, it can be seen in FIG. 4 that the first piece 5 has a lower end that is folded towards the interior, thereby defining a slanted region 9. The side of said first piece 5 that has the coating 2 is joined by means of thermo-fusion to the uncoated side of the skirt 10 of the second laminar piece providing the bottom 6. Likewise, the side of the second piece 6 that is coated with the coating 2 is joined by means of thermo-fusion to the side of the first piece 5 that has the coating 2.

[0062] The present invention is additionally illustrated using the following non-limiting examples.

EXAMPLES

Example 1

[0063] The method for producing the coated cellulosic laminar element according to the invention was used to produce a coated cellulosic laminar element. The paper was obtained from lignin-free chemical pulp, with a grammage of between 150 and 350 g/m.sup.2 and thicknesses of between 250 and 450 μm depending on the grammage. Starch was applied to one side, providing the coated cellulosic laminar element with good sealability and a good aesthetic finish on the surface. On the other side, a precoating of latex was applied to one side of the paper to between 6 and 7 g/m.sup.2 using a grooved-rod unit. Next, a first layer of an ethylene and an acrylic acid aqueous dispersion containing 26% solids and having a pH of between 7.5 and 9.5 and a grammage of between 4 and 5 g/m.sup.2 was applied to the same side using a grooved-rod or blade unit. The aqueous dispersion was dried by means of infrared radiation and drying in a hot-air hood, aiming for the temperature of the dispersion to not exceed 70° C. so as to avoid the need for a subsequent drying step. A second layer of the aqueous dispersion of the same ethylene and acrylic acid was applied to said same layer to between 6 and 7 g/m.sup.2 using a grooved-rod or blade unit. Said dispersion was dried by means of the same technique applied earlier. The combination of the coating on one side with the starch provides the coated cellulosic laminar element with good sealability.

[0064] In this way, a structure according to FIG. 2 was obtained.

[0065] It was verified that the coated cellulosic laminar element obtained was readily recyclable without requiring any intermediate processes or treatments.

Example 2

[0066] Said cellulosic laminar element produced in Example 1 was used by the receptacle producer to prepare receptacles similar to those in FIGS. 3 and 4. The sealing properties of the receptacles were excellent and the barrier properties were also very good given that the addition of coffee at a temperature of 90° C. did not result in any leakage through the bottom or through the side walls of the receptacle for 20 minutes. After these 20 minutes, the coffee cooled down, and there was no leakage once it had cooled either.

Example 3

[0067] The method for producing the coated cellulosic laminar element according to the invention was used to produce a coated cellulosic laminar element. Starch was applied to one side, providing the coated cellulosic laminar element with good sealability and a good aesthetic finish on the surface. On the other side, a precoating of latex was applied to one side of the paper to between 6 and 7 g/m.sup.2 using a grooved-rod unit. Next, a first layer of an ethylene and an acrylic styrenated aqueous dispersion containing 45% solids and having a pH of between 7.5 and 9.5 and a grammage of between 4 and 5 g/m.sup.2 was applied to the same side using a grooved-rod or blade unit. The aqueous dispersion was dried by means of infrared radiation and drying in a hot-air hood, aiming for the temperature of the solution to not exceed 90° C. so as to avoid the need for a subsequent drying step. A second layer of the aqueous dispersion of the same ethylene and acrylic styrenated was applied to said same layer to between 6 and 7 g/m.sup.2 using a grooved-rod or blade unit. Said dispersion was dried by means of the same technique applied earlier. The combination of the coating on one side with the starch provides the coated cellulosic laminar element with good sealability.