EP2497736A1

EP2497736A1 - Core for winding reels

Info

Publication number: EP2497736A1
Application number: EP11425058A
Authority: EP
Inventors: Elisio Ravanesi
Original assignee: Cartiera di Ferrara SpA
Current assignee: Cartiera di Ferrara SpA
Priority date: 2011-03-10
Filing date: 2011-03-10
Publication date: 2012-09-12
Also published as: EP2497736A8

Abstract

A core (1) for winding reels, particularly for reels of paper, cardboard, polymeric materials and the like, which is substantially constituted by a tubular element (2) comprising a plurality of strips (3) wound helically, at least partially overlapped and mutually associated. The strips (3) are made of a material chosen from paper, cardboard, polymeric materials and the like.

At least one of the strips (3), arranged in proximity to the outer surface of the tubular element (2), is impregnated with a substance that is adapted to confer a high level of water-repellence to the at least one strip (3a).

Description

The present invention relates to a core for winding reels.
As is known, cores for reels of paper and/or cardboard are widely available on the market, which are constituted by a plurality of strips (which are also typically paper or cardboard) wound helically and mutually overlapped and glued.
In order to achieve the gluing, use is usually made of various types of adhesive, both of the organic (such as for example amides or resins) and the inorganic type.
Whatever the type of adhesive chosen, it is commonly dispersed in an aqueous solution that results in the presence of a certain quantity of water trapped in the core at the end of the forming operations.
At the end of the forming, at least part of this quantity of water must therefore be caused to evaporate, so as to prevent this water from compromising the functionality of the adhesive and/or from causing an unacceptable loss of strength of the core.
The drying step, to which the core must therefore be subjected, has problems of critical importance, in that it is necessary to ensure the maximum uniformity of evaporation, in order to prevent shrinking from occurring in some areas, which are damp, with consequent warping and inflexion of the core itself.
Warping beyond a certain limit value, and hence the use of cores that are not perfectly straight, is unacceptable, since during the step of winding the paper there would be oscillations and consequent vibrations (as well as variations in the winding tension of the paper) which would be discharged onto the core, thus causing its breakage.
It is also necessary, in the steps following the steps just described, to pay particular attention to any absorption of water by the cores.
This is because after drying, the cores are stored in bundles, which may be massive and which are typically parallelepiped in shape. Since paper is a highly hygroscopic material, which tends to come into equilibrium with the ambient humidity, the outer cores of the bundles (and in particular the surfaces facing the atmosphere) are strongly subject to the risk of undergoing further phenomena of evaporation or absorption of water so as to come into equilibrium with the outer environment.
If, in the drying step, the core has been brought to a dampness level that is higher than the humidity level of the environment, then the outer cores will come to lose more water vapor than the cores within the bundle, with consequent inflexion of those cores.
This is a source of further drawbacks, since the consequent deformations cause workability problems, particularly for very long and very heavy cores, or for cores intended for work on high-speed machines.
Moreover, the vapor transferred to the outside of the core can affect the materials wound around the core, in some cases damaging them, possibly irreparably.
From the foregoing explanation, it appears evident that the process of making the cores (both in the drying step, and in the subsequent transport and storage steps) is affected by a number of drawbacks that cannot easily be solved, and which involve high percentages of defective products.
The aim of the present invention is to solve the above-mentioned problems, by providing a core that ensures the maintenance of its geometric properties, without the risk of unwanted deformations and inflexions, during the working steps.
Within this aim, an object of the invention is to provide a core that keeps its geometry unaltered, independently of the humidity conditions of the surrounding environment.
Another object of the invention is to provide a core that ensures respect for the integrity of the materials wound around it, without the risk of damaging them as a result of the evaporation, or in any case the exchange, of water and water vapor with the outer environment.
A further object of the invention is to provide a core that can be easily made from elements and materials that are readily available on the market.
A further object of the invention is to provide a core that can be made at low cost and safely applied.
This aim, as well as these and other objects which will become more evident hereinafter, are achieved by a core for winding reels, particularly for reels of paper, cardboard, polymeric materials and the like, substantially constituted by a tubular element comprising a plurality of strips wound helically, at least partially overlapped and mutually associated, said strips being made of a material chosen from paper, cardboard, polymeric materials and the like, characterized in that at least one of said strips, arranged in proximity to the outer surface of said tubular element, is impregnated with a predefined substance that is adapted to confer a high level of water-repellence to said at least one strip.
Further characteristics and advantages of the invention will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the core according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view of the core according to the invention;
Figure 2 is a greatly enlarged end elevation view of a detail of the core in Figure 1;
Figure 3 is a flow diagram showing the method according to the invention for producing the cores.

With reference to the figures, a core according to the invention, generally indicated with the reference numeral 1, is particularly suitable for winding paper, cardboard, polymeric materials and the like around it.
It should be made clear from this point onward that the use described above constitutes a preferred, but not exclusive, application of the core 1 according to the invention: the possibility is not excluded of using the core 1 for different purposes, which still fall under the scope of protection claimed herein, in accordance with the specific requirements.
The core 1 is substantially constituted by a tubular element 2 that comprises a plurality of strips 3 (for example, in number comprised between 20 and 40) wound helically and at least partially overlapped; the strips 3 are mutually associated, for example by means of the use of adhesives for gluing. These adhesives can be of various types, and preferably are selected from those that require a smaller quantity of water to evaporate subsequently.
The core 1 thus provided can reach extended lengths (for example longer than 3 meters) and can support reels that exceed 4.5 tonnes in weight.
The strips 3 are preferably made of a material selected from paper and cardboard, but the possibility is not ruled out of making use of a different material.
According to the invention, at least one of the strips 3, and more specifically at least one strip 3a arranged in proximity to the outer surface of the tubular element 2, is impregnated with a predefined substance, which is capable of conferring a high level of water-repellence to the impregnated strip 3 a.
The choice to make use of the externally arranged impregnated strip 3a achieves the preset objectives, since the impregnated strip 3a constitutes a form of barrier that prevents the exchange of water or water vapor through the outer surface.
The exit of water or water vapor can occur only through the inner surface, in ways that do not produce inflexions or warping of the core 1, thus ensuring observance of the shape restrictions imposed by the required quality standards.
Furthermore, the presence of the water-repellent outer layer prevents the passage of water from affecting the materials wound around the core 1, thus guarding against the danger of a deterioration thereof.
According to a first possible embodiment, the substance is a styrene-acrylic derivative, cationized with quaternary amino bases, dispersed in a solution of polyvinyl alcohol.
Alternatively, according to a second possible embodiment, the substance is a cationic polyurethane polymer.
The choice to use an aceto-vinyl compound in aqueous dispersion for the substance also lies within the scope of protection claimed herein.
According to a further possible embodiment, the substance is a fatty chain alkylketene compound, emulsified in water.
Furthermore, it is possible to make use of a substance constituted by a mixture of fluorine-based compounds. Conveniently, this last solution makes it possible to confer the ability to resist the passage of oils and fats in general, as well as water and water vapor, to the impregnated strip 3 a.
Advantageously, the core 1 comprises at least two strips 3a impregnated with a respective substance for conferring a high level of water-repellence to them: the selected substance can be the same for both of the two (or more) impregnated strips 3a, or for each impregnated strip 3a a specific substance can be used, different from the substance used for the other impregnated strips 3a.
With reference to the embodiment illustrated directly above, which involves the use of at least two impregnated strips 3a, it should be noted that one of these impregnated strips 3a can be selected in proximity to the inner surface of the tubular element 2: in this way, the evacuation (or the passage) of water or water vapor is possible only through the ends of the tubular element 2.
The method according to the invention is particularly suitable for the production of cores 1 intended for the winding of reels, and in particular for reels of paper, cardboard, polymeric materials and the like.
In a first step a., the method involves winding helically a plurality of strips 3, until a sufficient number thereof are wound so as to form a tubular element 2: the strips 3 are at least partially overlapped and mutually associated (for example by gluing).
In a second step b., at least one of the strips 3, arranged in proximity to the outer surface of the tubular element 2, is impregnated with a predefined substance, so as to confer a high level of water-repellence to the at least one impregnated strip 3a.
More specifically, the impregnation step b. involves immersing the strip 3 in a bath containing the substance.
The substance is preferably, but not exclusively, selected from a styrene-acrylic derivative, cationized with quaternary amino bases, dispersed in a solution of polyvinyl alcohol, a cationic polyurethane polymer, an aceto-vinyl compound in aqueous dispersion, a fatty chain alkylketene compound, emulsified in water, a mixture of fluorine-based compounds.
In practice it has been found that the core according to the invention fully achieves the set aim, since the choice to use a substance with which to impregnate at least one of the outer strips constituting the core, in order to confer a high level of water-repellence thereto, ensures the maintenance of its geometric properties, without the risk of unwanted deformations and inflexions, during the working steps.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. In addition, all the details may be replaced by other, technically equivalent elements.
In the embodiments illustrated, individual characteristics shown in relation to specific examples may in reality be interchanged with other, different characteristics, existing in other embodiments.
Moreover, it should be noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.
In practice the materials employed, as well as the dimensions, may be any according to requirements and to the state of the art.
Where the technical features mentioned in any claim are followed by reference numerals and/or signs, those reference numerals and/or signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference numerals and/or signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference numerals and/or signs.

Claims

A core for winding reels, particularly for reels of paper, cardboard, polymeric materials and the like, substantially constituted by a tubular element (2) comprising a plurality of strips (3) wound helically, at least partially overlapped and mutually associated, said strips (3) being made of a material chosen from paper, cardboard, polymeric materials and the like, characterized in that at least one (3a) of said strips (3), arranged in proximity to the outer surface of said tubular element (2), is impregnated with a substance that is adapted to confer a high level of water-repellence to said at least one strip (3a).
The core according to claim 1, characterized in that said substance is a styrene-acrylic derivative, cationized with quaternary amino bases, dispersed in a solution of polyvinyl alcohol.
The core according to claim 1, characterized in that said substance is a cationic polyurethane polymer.
The core according to claim 1, characterized in that said substance is an aceto-vinyl compound in aqueous dispersion.
The core according to claim 1, characterized in that said substance is a fatty chain alkylketene compound, emulsified in water.
The core according to claim 1, characterized in that said substance is a mixture of fluorine-based compounds.
The core according to one or more of the preceding claims, characterized in that it comprises at least two of said strips (3a) impregnated with a respective predefined substance, for conferring a high level of water-repellence to said at least two impregnated strips (3a).
A method for producing cores for winding reels, particularly for reels of paper, cardboard, polymeric materials and the like, which comprises the steps of:
a. winding helically a plurality of strips (3), so as to form a tubular element (2), said strips (3) being at least partially overlapped and mutually associated;

b. impregnating at least one of the strips (3), arranged in proximity to the outer surface of said tubular element (2), with a substance that is adapted to confer a high level of water-repellence to said at least one strip (3 a).
The method according to claim 8, characterized in that said impregnation step b. involves immersing said at least one strip (3a) in a bath containing a substance preferably selected from a styrene-acrylic derivative, cationized with quaternary amino bases, dispersed in a solution of polyvinyl alcohol, a cationic polyurethane polymer, an aceto-vinyl compound in aqueous dispersion, a fatty chain alkylketene compound, emulsified in water, a mixture of fluorine-based compounds.