MX2007009052A - Stretched wrapping film roll reinforced with laminated bands and method. - Google Patents

Abstract

A linear low density polyethylene (LLDPE) stretched base film roll longitudinally reinforced with one or several laminated bands which have a single or different widths, the same or a higher thickness than that of the base LLDPE stretched film, and a single or several configurations. The reinforced band or bands which are laminated and attached to the stretched LLDPE base film are made of the same substrate than that of the base film or of any other compatible substrate such as POF, PVC, PET, etc., said bands may be transparent, or with colours or prints, or a combination thereof. Said stretched film roll reinforced with laminated bands may be stretched between 30% and 380% with regard to the original length of the base film at a longitudinal direction. Moreover, the invention includes a method for laminating and assembling the band or bands to the stretched base film in two layers.

Description

"REINFORCED STRETCH FILM ROLL WITH LAMINATED BANDS AND METHOD" BACKGROUND OF THE INVENTION The present invention is directed to the art of packaging materials, and more particularly to the art of plastic materials for wrapping or uniting articles on a loading element as it can be a wooden platform, cardboard or plastic. The present invention relates to a roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or several bands of one or more widths, of the same thickness as the stretch film of linear polyethylene of low density base or higher. The reinforcing band or bands that are laminated and engargoladas to the stretch film of linear low density polyethylene base can be from the same substrate as the base film or some other compatible substrate such as POF, PVC, PET, or others, these can be transparent, colored or printed. Said Stretch Film Roll reinforced with laminated bands can be stretched between 30% and 380% of its original length in the longitudinal direction. Description of the prior art used: The stretchable films of the prior art are used in connection with a wide variety of packaging applications. In said wrapping process, a wooden, cardboard or plastic platform or some other means of support is loaded with boxes, products, or elements to be wrapped and the different elements are wrapped to themselves and to the supporting element with several turns of Stretchable film to have a single unified element for transport. There are various methods to unify loads with the stretchable films of the prior art, from the manual application where a person can wrap said load by fixing a tip of the stretchable film under one of the corners of said load, stretching it and applying it to the load while walking around it, always maintaining a constant tension to make the film stay stretched, this for a certain number of turns until the load is completely unified, until fully automatic applications where specialized equipment adequately applies the stretch film to loads until achieving the necessary unification to avoid movement damage during storage and transport. In recent years, high-performance stretch films have been developed that have reduced the thickness of the films with the same security in the envelope but with a smaller amount of stretch film. U.S. Patent No. 5,013,595, issued to Parry on May 7, 1991, which corresponds to a film reinforced with bands or bands stuck with adherents. These bands can be different color to the base film to achieve a distinction in the envelope and this way "customize" the unified elements. However, the fact of sticking the band or bands has as disadvantages, a higher manufacturing cost and the structural benefits granted to this type of films with auxiliary bands are opposed by the higher cost. Another drawback is the adhesive used to bond the strip (s) to the base film, it is an isobutene compound which under certain conditions of atmospheric or controlled temperature and certain relative humidity decomposes and the integrity of the laminate is lost, causing the product does not work as designed. US Patent No. 4,691,497, issued to Lancaster on September 8, 1987, offers a method and apparatus for assembling or laminating and dispensing multilayer film and wrapping a load with the multi-layer film, which includes a film dispenser that receives a plurality of film layers to form a multi-layer film and dispatch it. The load is rotated relative to the film dispenser to wrap the multi-layer film in the load and where the tension is maintained in the multi-layer film between the film dispenser and the load. Base material like a foamed film, UV resistant material, or reinforcing fabric are inserted between the plurality of films prior to the dispatch of the multi-layer film. Rollers and a clutch and brake assembly are used to intermittently feed the base material layer. This system allows making the multi-layer film assembly "in-situ" and depends on the equipment described within the same invention to carry out such wrapping. This above makes the invention a captive system to the equipment and can not be done in other wrapping equipment. Other ways to reinforce stretch film, both unstretched and pre-stretched, are reinforced edges, which is achieved by annealing the edge, with a hem or fold on the edge. These reinforcements harden the edges of the film, which makes it more prone to damage. The prior art has also supplied pre-stretched films with reinforced edges, however, it has not supplied pre-stretched films with longitudinal reinforcement bands in the area not comprising the side edges of said film. U.S. Patent No. 5,531,393, issued to Salzsauler in July 1996, provides a roll of stretched plastic film with an engraved surface to enclose air and thus facilitate unwinding of the film, stretched between 50 and 300 percent of the original length of the film, is used to wrap parquet loads, and specifically includes a fold on the edge to reinforce the edge, such a folded edge is made in a manner that minimizes stacking of the folded edge on the roll. It is a roll of stretchable pre-stretched film reinforced only at the longitudinal edges.

US Patent No. 5,565,222, issued to Scherer on October 15, 1996, presents an apparatus for bending edges of stretch film as well as a film with bent edges. A strip of stretch film material is provided for wrapping, with flat and double thickness folds at the opposite edges. The bending strip is made in an apparatus having a first roll of a width less than the width of the material with which it is generally fed to the machine by which the opposite margins of the material project beyond the opposite ends of the roll , and a second roller for guiding the strip at an acute angle from the first roller causing the opposite edges to bend. The strip is held taut by a tension roller or some other means, and guide bars are provided to bend the opposite edges beyond a 90 degree angle so that they continue to be bent inwardly against the main body of the strip, resulting in a stretchable pre-stretched film reinforced by bending the longitudinal edges. U.S. Patent No. 5,766,773, issued to Paulett on June 6, 1998, presents an invention where two sheets of stretch film are assembled or laminated to one another by means of the intrinsic adhesion forces in each sheet . Said lamination is subsequently "drilled" by means of hot needles to physically join the two layers by means of heat at the edge of the perforations. Said lamination when stretched allows the holes to be lengthened in a controlled manner and causes said lamination to allow the products that have been wrapped to "breathe". Said invention has been developed to wrap mainly easily perishable products, products that still come out hot from their process and are wrapped and that upon cooling produce condensation in the inner part of the envelope, by the characteristic of this invention the condensation comes out through the elongated holes . U.S. Patent No. 5,953,888, issued to Martin-Cocher on September 21, 1999, presents a process for making pre-stretched film, as well as the apparatus and method required for the same when applied to an outer wrap . In this invention, the stretch film is stretched over at least one roller having several diameters about its axis of rotation, such that it forms parallel longitudinal zones in the stretch film having different degrees of stretch. These zones allow, in particular, to "encapsulate" the objects to be wrapped or to provide reinforced areas to contain the products to be wrapped. The particular application of this invention is for the wrapping of beverage containers and does not add bands per se, but modifies the base film by means of differential stretching to conform to the outer silhouette of what is to be wrapped. U.S. Patent No. 6,592,699, issued to Mehta on July 15, 2003, presents a process for manufacturing highly stretched film having permanently sealed edges with - -They are almost invisible. A folding device bends the edges of the film to form bent edges. The bent film is passed through a support mechanism having two hot rollers. A series of contact point rollers apply pressure to the bent film while it is heated by hot rollers. The pressure at the point of contact combined with the heat imparted by the hot rollers causes a thermal welding of the bent edges resulting in a permanent thermal seal. The stretched film resulting from this process has permanently sealed edges with heat that will not separate, which prevent tearing of the film during the process and subsequent use when wrapping the loads. Like the previous ones, it is a roll of stretchable pre-stretched film reinforced only at the longitudinal edges. What is needed is a roll of linear low density polyethylene (LLDPE) base film, longitudinally reinforced with the lamination and engargolado of one or several bands of one or several widths, of the same thickness as the stretch film of linear polyethylene of low density base or higher. The reinforcing bands or bands that are laminated and engargoladas to the stretch film of linear low density polyethylene base can be of the same substrate as the base film or some other compatible substrate such as POF, PVC, PET, or others, these can be transparent, colored or printed. Assembled the band or the bands to the stretchable base film without any adherents. Said Stretch Film Roll reinforced with laminated and engargoladas strips can be stretched between 30 and 380% of its original length in the longitudinal direction. Said roll can be used in any type of conventional equipment for stretch film wrapping either low platform, high platform, rotating arm or orbital without modifying outside the limits of said equipment, whether manual, semi-automatic or automatic.

DESCRIPTION OF THE INVENTION One of the objectives of the present invention is to obtain a roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or several bands of one or more widths, of the same thickness as the stretchable linear polyethylene film of low density base or higher. Another objective related to this invention is to provide a roll of stretch film of linear low density polyethylene (LLDPE) base wherein the band or bands of reinforcement can or can be of a width ranging from 10mm to 200mm, and which can be indistinctly laminated longitudinally the bands of different widths to the base film to achieve the force of containment necessary for the application. Another object related to the present invention is to provide a roll of stretch film of linear low density polyethylene (LLDPE) base wherein the reinforcing strip or bands can be of a substrate different from the base film. Another object related to the present invention is to provide a roll of stretch film of linear low density polyethylene (LLDPE) base wherein the reinforcing strip or bands can be of a substrate different from the base film. This band or bands can be of similar substrates such as POF, PVC, PET, or some other substrate compatible with the base film.

Another object related to the present invention is to provide a roll of stretch film of linear low density polyethylene (LLDPE) base wherein the reinforcing strip or bands can be transparent as the base film, or they can be colored, or they can be printed or recorded. Another objective related to the present invention is to provide a roll of stretch film of linear low density polyethylene (LLDPE) base wherein the roll can be stretched from 30% up to 380% of its original length. Another objective related to the present invention is to provide a roll of stretchable linear low density polyethylene (LLDPE) base film longitudinally reinforced with the lamination of a band or several reinforcing bands in a two stage rolling mill. The first stage consists of two steel rollers that exert controlled pressure at the moment of rolling between the base film and the strip (s). The second stage consists of a roller with the pressure surface engraved by means of knurling, electro-erosion or acid that exerts a controlled pressure on the band or bands having as a backing a roll lined with polyurethane that has a minimum hardness of 90 in the Shore A scale. Another object more related to the present invention is to supply a carriage of the rolling mill that is separated from the base of the machine, said carriage rotates by means of hinges and - open to allow easy feeding of the base film and the band or bands, and once the materials have been loaded into the machine the car is locked again in the closed position by a pair of pneumatic cylinders with the base stretch film together with the band or bands between the pressure rollers and the engraved rollers to create a quick and easy movement step to load the material and carry out the method. Yet another objective of the present invention is to provide a rewinding station with pneumatic tension control, to achieve longitudinally reinforced stretchable film rolls with a band or several bands consisting of winding tension and outer diameter. In short, a roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or more bands of one or several widths, of the same thickness as the stretch film of linear polyethylene of low density base or greater, which may be of the same raw material as the base film or some other compatible substrate, which may be transparent, of colors, or printed. Said roll can be used in conventional wrapping equipment, whether manual, semi-automatic, automatic low or high platform, rotary arm or orbital. It is manufactured in a team with a two-stage rolling mill and is easy to load. An advantage of the present invention is that it produces a stretchable film for wrapping pallets which is longitudinally reinforced with a band or several bands and which can be pre-stretched between 30% and 380% of its original length according to the needs of the particular applications. A further advantage of this invention is that it provides a roll of stretch film for wrapping pallets which is longitudinally reinforced with a band or several bands for wrapping pallets that provides a greater holding force to the wrapping of the pallets by the reinforcement or laminated in two stages to the base film when they are applied the same number of turns as a conventional stretch film, achieving a greater integrity in the load than with conventional stretch film. A further advantage of this invention is that it provides a roll of stretch film for wrapping pallets that is longitudinally reinforced with a band or several bands for wrapping pallets that weighs approximately two-thirds of a conventional stretch film in length and equivalent holding force, this allows the reduction of injuries by the effort required to load the wrapping machines with the objective rolls of the present invention. Another advantage of this invention is that it provides an easy and quick movement to load the raw material and carry out the method.

- - Brief description of the figures: These and other details of my invention will be described in connection with the attached figures, which are provided only by way of illustration and not in limitation of the invention. Figure 1.- It is an illustrative view of the prior art for conventional stretch film rolls. Figure 2.- It is an illustrative view of the technique proposed by the present invention. It is shown illustratively with two longitudinal reinforcement bands. Figure 3.- It is a schematic side view of the longitudinally reinforced stretchable film object of the present invention at the moment of rolling in both stages, as well as the finished coiling of finished roll. Figure 4a.- Detailed side view in section of a single band. Figure 4b.- Detailed side view in section with the band bent at the edges. Figure 4c Detailed side view in section with the band folded on itself in half.

Figure 4d.- Detailed side view in section with the band folded on itself with the edges equal. Figure 5.- It is a schematic rear view of the base stretchable film at the moment that, in this illustration, two strips are laminated through the rolling station 1. Figure 6.- It is a schematic rear view of the base stretchable film when it is joined or assembled, in this illustration, two bands, through the rolling station 2. Figure 7.- It is a schematic detailed view of the process of engargolado or assembled in the lamination station 2. Figure 8.- It is a schematic side view with the carriage of the rolling train open to facilitate the feeding of the film for its processing. Figure 9.- It is a schematic front view of the rewind station. PREFERRED METHOD FOR CARRYING OUT THE INVENTION: In Figures 1 to 9, the present invention includes a stretch film longitudinally reinforced with a band or several bands for wrapping loads or large articles, a two stage rolling apparatus for carrying the present method invention, and a finished roll of stretchable film longitudinally reinforced with one or more bands. Figure 1 shows a typical roll of conventional stretch film of the prior art 60. Where the base film being of what is called "high performance" has an approximate thickness of thirteen microns. Normally this type of products is supplied in widths ranging from 500mm to 760mm. It has been searched by means of new - Resin-shaped resins lower the caliber with the same result of forces of containment, however, in thicknesses less than thirteen microns have not been able to exceed 225% stretch. Figure 2 shows the Roll of Stretch Film reinforced with a band or several bands by means of lamination in two stages 11. It should be noted that a roll with two bands 10 is shown for illustration only. You can assemble rolls with 1 band or multiple bands that can be of the same thickness of the base film or larger, can also be a compatible substrate such as POF, PVC or PET, for example, they can also be of different widths depending on the application specific, and placed not necessarily symmetrical in the width of the base film, said band or bands can be simple Fig. 4a, folded on the edges Fig. 4b, folded in half on itself Fig. 4c, or folded in half with equal edges Fig. 4d. In Figure 3, a stretchable film reinforced with one or more strips 11, is laminated in two stages with one or more reinforcement strips 10, from a roll of stretchable base film that does not have a thickness greater than twelve microns 12, laminated pressure in a first stage through the pressure rollers 18 and 19, whose pressure is controlled by the pistons 24 and 25 that can be seen in Fig. 5, with one or more reinforcing bands 10 that previously pass through the folding station 23, wherein the required bending configuration is adjusted, either to produce the band or flat bands Fig. 4a, or the band or bands bent at the edges Fig. 4b, or the band or bands folded in half on themselves Fig. 4c, or the band or bands folded in half with equal edges Fig. 4d. The base stretch film laminate 12 with the band or bands 10 is pulled through the pressure rollers of stage two laminate 16 and 17 by means of the drive roller 15, in this stage two rolling the band or the bands 10 that were already laminated to the base stretch film are riveted or engargoladas to the base stretch film 12, as can be seen in Fig. 6 and the detail of Fig. 7. The stretch film reinforced with one or more bands continues to be pulled by the drive roller 15 and is coiled to a cardboard or plastic center 20 which is mounted on the shafts 34 and 35 of FIG. 9 and which is being pressed on the drive roller 15 by means of the pneumatic pistons 32 and 33 in a controlled manner to ensure an adequate rewinding tension of the reinforced stretch film roll with one or more bands 11. In FIGS. 4a, 4b, 4c and 4d, the profile or configuration of the band or bands can be appreciated schematically. and reinforcement that can be achieved in the present invention. The substrate, the width of the band or bands, the thickness, the color or printing of the same and the amount of bands that are required are determined according to the specific needs of the customers. Any of the configurations or any combination of configurations is - -located in the bending station 23 shown in Fig. 3 and 8. In this station the benders can be adjusted to achieve any of the configurations detailed in Figures 4a, 4b, 4c and 4d for the band or bands that are required. It should be mentioned that the band or bands when they are bent are much more resistant than when they are flat and although they are of a smaller thickness they have greater elongation and resistance than those that are not bent. Figures 6 and 7 detail what makes our invention novel. Figure 6 shows the laminate previously assembled by the base stretch film 12 and in this case two reinforcing bands 10 by the rollers 18 and 19 of figure 5, passing through the second stage of rolling between the knurled or engraved pressure rollers by acid 17, and the roller coated with polyurethane 16. The knurled pressure rollers 17 exert pressure on the laminated assembly of the base film 12 and the reinforcing band or bands 10 by means of two pneumatic pistons 27 and 28, whose pressure is regulated according to the number of bands, or the configuration of the same, and is transmitted to the rollers by means of the arrow 26. In FIG. 7 the knurled pressure roller 17, which is engraved with the knurling of step ninety six and machined to half its nominal height, so as to have a truncated knurling, this is done in order to avoid that the films can be punctured and have a weak assembly. The diamond 50 of the knurled roller 17 presses on the reinforcement strip 10 and is in turn on the base stretch film 12 and these three 51 penetrate the polyurethane pressure roller 16. As said polyurethane pressure roller 16 is of a minimum hardness of ninety on the Shore A scale, has enough consistency to withstand the penetration of the knurling with the films, both of the band 10 and the base stretch film 12, without deforming and achieving a binding 52 in such a way that the reinforcement band 10 is mechanically assembled to the base stretch film 12. In this way, the strip or bands do not require adhesives or any other fixing element to be permanently assembled to the base stretch film. Figure 8 schematically shows in side view the carriage of the rolling mill 53 separated from the main structure 54 of the machine. This facilitates the introduction of the base stretch film 12 as it passes in front of the pressure rollers 19 and 16 to the drive roller 15 and be manually wrapped to the center of cardboard or plastic 20 for the next roll of stretchable film reinforced with one or more bands. 11. Also in that open position of the rolling train carriage 53, the reinforcing strip or bands 10 can be fed by the bending station 23 and facing the inner face of the pressing roller 18 until it passes the knurled roller or rollers 17, leaving the tip of the band or reinforcement bands 10 hanging on the outer face of the carriage of the rolling mill 53, at that moment it can be assembled in the operating position of said carriage and - -fix in the closed position by means of the pneumatic cylinders 54 and 55. Once in the closed position, the appearance of the equipment seen in section is as shown in Figure 3, it is possible to proceed to operate the equipment to effect the unbundling process of the base stretch film 12, the strip or bands 10 and laminar between stage one and step two described above, and rewinding to form a roll of stretch film reinforced with one or more bands 11. Figure 9 shows a roll of stretchable film reinforced with one or more strips 11 already finished wound on a cardboard or plastic center 20, which is supported by the fixed shaft 34 and the movable shaft 35. These shafts receive pressure on part of the pneumatic cylinders 32 and 33 , which are graduated according to the final finish that is required in the roll, less pressure produces looser rolls and a larger outside diameter, higher pressure produces more tight rolls and smaller outer diameter. In this figure, the length counter 55 can be seen to give the roll the exact amount of length required. In use, the Reinforced Stretch Film with one or more strips is placed in the roll holder of the wrapping machine, whether manual, semi-automatic, automatic, rotary or orbital arm, unrolled and passed through the pre-train. - Stretch own of the machine, or through the feeding rollers in case it has no pre-stretched train, once it has been fed up to this point the equipment is ready to wrap the loads. We have proven that we outperform films that are up to 50% thicker, have a greater containment force up to 15% more, less weight in the envelope using the same wrapping pattern up to 60% less, greater stretching up to 70% more than the product of the previous technique used, which results in greater loads for the same length of material. In short, the present invention offers great performance advantages at lower costs, less waste to recycle, and less fatigue in the operators that load the wrapping machines with the stretchable film rolls reinforced with one or more objective bands of this invention It is understood that the The above description is provided merely for illustration and not in limitation of the invention and that various modifications can be made without departing from the essence of the invention as claimed.

Claims (13)

1. CLAIMS Having sufficiently described my invention, I consider as a novelty and therefore claim as my exclusive property, what is contained in the following clauses: 1. A roll of linear low density polyethylene (LLDPE) base film, longitudinally reinforced with the lamination of one or several bands. Said Stretch Film Roll reinforced with laminated bands can be stretched between 30 and 380% of its original length in the longitudinal direction. Used to wrap parquet loads or packaged items that need to be unified economically and efficiently.
2. 2. The linear low density polyethylene (LLDPE) stretchable film roll, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 1 where the band or bands may be of the same thickness as the base stretch film or higher.
3. 3. The roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or several bands mentioned in Clause 1 where the reinforcing band or bands are of different widths from 10mm to 200mm inclusive.
4. 4. The roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or several bands mentioned in Clause 1 where the configuration of the band or bands can be flat without folds, or with the edges bent, or folded in half on itself, or folded on itself with equal edges.
5. 5. The roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 1 where the bands, when it comes to more than one, can be of different thicknesses, configurations, widths, substrates, colors or printed.
6. 6. The linear low density polyethylene (LLDPE) stretchable film roll, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 1 wherein the band or bands may be of a different substrate than the base stretch film as POF, PVC, PET, or some other compatible substrate.
7. 7. The linear low density polyethylene (LLDPE) stretchable film roll, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 1 where the band or bands may be colored.
8. 8. The linear low density polyethylene (LLDPE) stretchable film roll, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 1 where the band or bands can be printed.
9. 9. The roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 1 where the lamination of the band or bands is done in two stages.
10. 10. The roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or more bands mentioned in Clause 9 where the first stage of fixed lamination by means of pressure rollers controlled the band or bands to the base stretchable film.
11. 11. The roll of stretch film of linear low density polyethylene (LLDPE) base, longitudinally reinforced with the lamination of one or several bands mentioned in Clause 9 where the second stage of laminating or assemble the band or bands to the film Stretchable base by means of one or several rollers with a truncated knurling having as backing roller one coated with polyurethane with a minimum hardness of 90 on the Shore A scale.
12. 12. A method for laminating and assembling a band or several reinforcing bands to a stretch film base in two stages wherein the first stage of lamination fixed by means of pressure rollers controlled the band or bands to the base stretch film.
13. 13. The method of Clause 12 to laminate and assemble a band or several reinforcement bands to a two-stage base stretchable film where the second stage of laminating or assemble the band or bands to the base stretch film by means of one or several rollers with a truncated knurling having as a back-up roller one coated with polyurethane with a minimum hardness of 90 on the Shore A scale.