PROCESS FOR HEAT SHRINKING A FILM WRAPPED BUNDLE OR ARTICLE

Abstract

A process for heat shrinking a falm wrapped bundle or article that includes receiving the handle strip film and the wrapping film in either or both a static unit and a laser unit configured to emit amplified light, bonding the handle strip to the wrapping film by passing the handle strip film and the wrapping film in an overlapping relationship through the static unit and/or a laser unit, receiving the bonded handle strip and wrapping film directly to a perforation module that includes at least one of a handle rotary perforator and/or a laser perforator unit configured to emit amplified light and providing openings in the wrapping film adjacent the handle strip, film wrapping the bundle having the bonded strip over the bundle, and heat shrinking the film wrapped article causing the strip to seal to the film wrapped article.

Description

FIELD OF THE INVENTION

The present invention relates wrapping an article with a heat shrink film having a handle.

The following patents are incorporated by reference in its entirety, U.S. Pat. No. 7,836,670 filed on Oct. 18, 2006 titled “Perforated Film Wrapping Machine”, U.S. Pat. No. 8,424,272 filed on Apr. 23, 2013, titled, Apparatus and process for wrapping an article with a heat shrink film having a strip that acts as a handle, and U.S. Ser. No. 16/869,261, filed on May 7, 2020, titled handle for heat shrink film, all filed by the same inventor.

BACKGROUND OF THE INVENTION

Usually a handle is applied to the wrapping film on the outside of a bundle or a wrapped article. The handle is usually glued on the outside of the pack. The term bundle will be used to mean a single article as well as a collection of articles such as bottles. The adhesion of the glued handles to the wrapping material can be affected by heat and dryness of heat shrunk film and the quality of the glue. These handles tend to delaminate as the load increases. The closest prior art is described in U.S. Pat. No. 8,424,272. This patent teaches a strip of material made from a composition that allows the strip to adhere or cling to the wrapping film to prevent the strip from wandering while resting on the wrapping film. The problem with this solution was that the strip still tended to wander and was not always in direct contact with the wrapping film. In places where there was no contact the handle film could not seal (weld) with the wrapping film. Also, there was a need for the handle strip and the wrapping film be capable of being recycled together.

Therefore, a need exists to overcome the problems with the prior art as discussed above.

SUMMARY OF THE INVENTION

The invention provides a process for heat shrinking a film wrapped bundle or article that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type. The handle is made from a strip of material wherein the strip is completely enclosed inside the wrapping film. The strip is adhered to the film by creating an electrostatically charge.

With the foregoing and other objects in view, there is provided, in accordance with the invention, a process for heat shrinking a film wrapped bundle or an article having a handle strip film bonded to the inside of a wrapping film made from a material that seals to the wrapping film during the heat shrinking and comprising the steps of receiving the handle strip film and the wrapping film in at least one of a static unit and a laser unit configured to emit amplified light, bonding the handle strip to the wrapping film by passing the handle strip film and the wrapping film in an overlapping relationship through the at least one of a static unit and a laser unit, receiving the bonded handle strip and wrapping film directly to a perforation module that includes at least one of a handle rotary perforator and/or a laser perforator unit configured to emit amplified light and providing openings in the wrapping film adjacent the handle strip that would allow one to grip over the handle, film wrapping the bundle having the bonded strip over the bundle so that the strip is enclosed by the wrapping film, and heat shrinking the film wrapped article causing the strip to seal to the film wrapped article.

The above problems are solved by creating an electrostatic bond between a strip handle and the wrapping film. The strip is electrostatically bonded to the wrapping film. The electrostatic bonding causes the strip film to stay in almost constant contact with the wrapping film. This allows almost all of the entire strip film to seal (weld) with the wrapping film. Also, the electrostatic bond acts to reduces or prevents the wandering of the strip handle film. The static bonding provides better control and tensioning of the layered films.

The handle strip is made of a material which can thermally adhere to the heat shrink film by sealing (welding) during heat shrinking. Preferably the strip will be made of the same material or similar composition as the heat shrink film web so that the maximum adhesion will be achieved and will be heat shrinkable. The carrying load will dictate the thickness and the width of the handle strip. Usually a minimum of 2 mil. thickness of low-density polyethylene is required for the strip handle. In one embodiment, however, testing has shown that a 1 mil. thickness may be utilized with a machine direction oreiented polyethylene (MDO PE), which is stronger than PE and also recyclable with PE. Therefore, the film material may utilize mono source to the entire plastic wrap can be beneficially recycled together.

The invention is not limited to any particular heat shrinking film wrapping machine or process where a handle is desired. Although the invention is illustrated and described herein as embodied in a process for heat shrinking a film wrapped bundle or article, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention.

Other features that are considered as characteristic for the invention are set forth in the appended claims. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. The figures of the drawings are not necessarily drawn to scale but, where applicable, may be utilized to support a particular structural configuration or geometric relationship between components utilized in the assembly.

Before the present invention is disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms “a” or “an,” as used herein, are defined as one or more than one, wherein the utilization of “a” or “an” does not mean multiple structures with various functions may be utilized to equate to single claimed structure with claimed functionality. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The terms “including” and/or “having,” as used herein, are defined as comprising (i.e., open language). The term “coupled,” as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term “providing” is defined herein in its broadest sense, e.g., bringing/coming into physical existence, making available, and/or supplying to someone or something, in whole or in multiple parts at once or over a period of time. Also, for purposes of description herein, the terms “upper”, “lower”, “left,” “rear,” “right,” “front,” “vertical,” “horizontal,” and derivatives thereof relate to the invention as oriented in the figures and is not to be construed as limiting any feature to be a particular orientation, as said orientation may be changed based on the user's perspective of the device. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.

As used herein, the terms “about” or “approximately” apply to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In many instances these terms may include numbers that are rounded to the nearest significant figure. In this document, the term “longitudinal” should be understood to mean in a direction corresponding to an elongated direction of the film in the manufacturing process.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and explain various principles and advantages all in accordance with the present invention.

FIG. 1 shows a handle strip being applied to a heat shrink film for wrapping a bundle of bottles by forming an overlap.

FIG. 2 shows a bundle of bottles wrapped in heat shrink film with a handle encased within the heat shrink film.

FIG. 3 shows a handle strip being applied to a heat shrink film for wrapping a bundle by pushing the bundle through a vertical film curtain.

FIG. 4 shows a bundle of bottles wrapped in heat shrink film with a handle strip encased within the heat shrink film where the handle is located on the upper portion of the bundle.

FIG. 5 shows an electrostatic unit for bonding the handle strip to the wrapping film.

FIG. 6 shows a handle strip being applied to a heat shrink film for wrapping a bundle of bottles by forming an overlap in accordance with another embodiment of the present invention.

FIG. 7 shows a handle strip being applied to a heat shrink film for wrapping a bundle by pushing the bundle through a vertical film curtain in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION

While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. It is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms.

FIG. 1 is like FIG. 1 in U.S. Pat. No. 8,424,272. The main difference is an electrostatic bond between the strip and the wrapping film.

FIG. 1 shows a single roll (17) having a continuous strip (16) of plastic material to be used as a handle being fed inline simultaneously with a heat shrinkable film wrapping film (1) from film roll (2). The handle strip (16) and shrink film (1) joint together at film feed rollers (13). If desired there can be multiple strip handles simultaneously joined to the wrapping film. Afterwards the films are bonded together with a static unit (20). After film bonding, the bonded film (21) moves through a handle slot perforation module (structure) (14). The perforations are caused by pressing a knife with pointed teeth into the film to perforation the film creating tear line 18 shown in FIG. 2. The same type of structure is used for perforation unit (12). The module is adjustable to accommodate both single and dual handles, or multiple handle widths, located in the machine flow direction or in the transverse direction. The handle perforation module (14) will make two perforated lines thru the shrink film outside of each handle strip (16) to create a tear line 18 for a person's fingers to enter the wrapping film and grip the handle. The handle perforation module (14) can be located before or after the perforation unit (12).

The strip bonded film proceeds to the film perforation unit (12) where it is perforated across the width of the bonded films to provide desired length of bonded film to wrap the article (3). Then the bonded films advances to the separation rollers (11) that separates the perforated film at the required length and advances the front edge of the bonded films shown as flap (10) on the top of transfer conveyor (7). A bundle (3) is positioned on top of flap (10). As the bundle advances on the transfer conveyor (7) the wrap arm (8) lifts the tail edge of the bonded film and covers the bundle (3) with the bonded film (21). As the transfer conveyor pushes bundle (3) onto the heat shrink tunnel conveyor (22), the tail edge of the bonded film is pushed underneath the bundle (3) to form an overlap (19) with flap (10). By adjusting the location of the flap and the length of the bonded film, the overlap (19) is usually in the center line of the package as shown in FIG. 2. The overlap (19) creates a sandwich of strip with underlayers of film, strip and film. When the wrapped article is heat shrunk the strip will seal to the film in most all areas to provide a good bond for the handle. Usually at least 85% of the handle film seals to wrapping film. The overlapped portion (19) will also seal and form a welded bond.

FIG. 3 shows an alternative film wrapping application. A single roll (17) or multiple rolls (17) of handle strip of plastic material (16) is fed inline simultaneously with the top shrink film (1) from roll (2). The handle strip (16) and shrink film (1) joint together at the roller (9). Immediately afterwards the films pass through the static unit 20 Then the bonded films (21) advances into a handle slot perforator (14) that is adjustable to accommodate both single and dual handles and multiple handle widths. The module (14) can be positioned in the machine flow direction and transverse direction. The handle slot perforator (14) will cut two perforated lines thru the top film (1) outside of each handle strip (6) to create a tear line (18) for a person's fingers to enter the film. The bonded films (21) then proceed to the top film feed rollers (13) that feeds the desired length of top film required for each product. The bonded films (21) and the lower film (4) join in front of the heat seal blade (15) to form a curtain of film (5). A bundle or article is are either conveyed or pushed by pusher (13) through the film curtain (5) which sleeve wraps the bundle inside the bonded film (16) and bottom film (4). A hot blade (15) simultaneously cuts the bonded film (16) and the film (4) behind the bundle (16) and joins the films on both sides of the cut. One side creates a welded joint that recreates the vertical film curtain (5). The other side forms a weld joint that completes the film wrapping of the bundle. The bonded strip film (21) is located on the top portion of the bundle. The bundle 3 advances into the shrink tunnel (22) where the handle strip and the shrink film melt together to create a strong integrated handle in the shrunk film package (23). The handle strip is usually orientated on the center line of the package as shown in FIG. 4.

FIG. 5 shows a static unit (20). This unit consists of a remote mounted power unit (31) that transfers 20 KV@150 uA DC thru a high-tension lead (31) running out to a static probe (33) housed in an open-ended insulator sleeve (34). The film and handle films pass between the static probe (33) and a grounding strap/bar (35) that is bonded to the machine's frame. The static unit (20) creates a bond between the films allowing the layered films to adhere and to maintain contact to each other.

FIG. 6 shows an alternative film wrapping application block diagram. In particular, the diagram is substantially similar to FIG. 1 with the exception of including either or both a laser unit and/or a static unit 20 that receives the film from the feed roller 13. The laser unit 20 may further facilitate in the bonding of the film strip 16 and shrink film 1 before reaching a second laser unit that facilitates in perforating the handle slot. With further reference to FIG. 7, which is ubstantially similar to the block diagram depicted in FIG. 3, the laser unit and/or static unit 20 receive the films 1, 16 after a roller 9 and then, after bonding, are received by another roller that directs the bonded films 20 to the laser perforator 14. In one embodiment, the laser units may be CO2 lasers that may be 30/55/70/100 watts having a power supply of 110V˜220V/50 Hz˜60 Hz, depending on the application. To bond the films, the laser unit may also use a coherent laser with an aerosol spray.

More specifically, the new process includes receiving the handle strip film 16 and the wrapping film 1 in a unit that may include one or both of the static unit and/or a laser unit 20 configured to emit amplified light to bond the films together. Thereafter, preferably without passing the bonded films through any other units and/or processing modules, but preferably over a roller as depicted in the FIG. 7, the bonded films 1, 16 are received to a perforation module that may include one or both of a handle rotary perforator and/or a laser perforator unit configured to emit amplified light that provide openings in the wrapping film adjacent the handle strip that would allow one to grip over the handle. Specifically, the static charge and/or laser perforation perforate and stick the handle film to the wrapping material.

Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present disclosure. For example, while the embodiments described above refer to particular features, the scope of this disclosure also includes embodiments having different combinations of features and embodiments that do not include all of the above described features.

Claims

1. A process for heat shrinking a film wrapped bundle or an article having a handle strip film bonded to the inside of a wrapping film made from a material that seals to the wrapping film during the heat shrinking and comprising the steps of: receiving the handle strip film and the wrapping film in at least one of a static unit and a laser unit configured to emit amplified light;bonding the handle strip to the wrapping film by passing the handle strip film and the wrapping film in an overlapping relationship through the at least one of a static unit and a laser unit;receiving the bonded handle strip and wrapping film directly to a perforation module that includes at least one of a handle rotary perforator and/or a laser perforator unit configured to emit amplified light and providing openings in the wrapping film adjacent the handle strip that would allow one to grip over the handle;film wrapping the bundle having the bonded strip over the bundle so that the strip is enclosed by the wrapping film; andheat shrinking the film wrapped article causing the strip to seal to the film wrapped article.

2. The process according to claim 1, further comprising: bonding the handle strip to the wrapping film by passing the handle strip film and the wrapping film in an overlapping relationship through the laser unit; andreceiving the bonded handle strip and wrapping film directly to the laser perforator unit that provides openings.

3. The process according to claim 1, further comprising: electrostatically bonding the handle strip to the wrapping film with the static unit that includes a ground strap or bar and having a static probe receiving current and housed in an open-ended insulator sleeve, wherein the ground strap or bar are configured in a directly overlapping configuration.

4. The process according to claim 3, further comprising: overlapping a strip bonded wrapping film during film wrapping the article whereby the strip is sandwiched between two layers of wrapping film so that heat shrinking seals the strip to both layers of film.

5. The process according to claim 4, wherein the strip bonded film is perforated to provide a predetermined length of film for wrapping the article.

6. The process according to claim 1, wherein the wrapping film and strip are made of the same material and are heat shrinkable.

7. The process according to claim 1, wherein a flap of the strip bonded wrapping film is pushed on a conveyor.

8. The process according to claim 1, further comprising: forming a vertical curtain by joining a strip bonded wrapping film with a wrapping film.

9. The process according to claim 8, further comprising: pushing a bundle through the vertical curtain and cutting the film with a hot sealing blade that joins the cut films to form the vertical curtain.

10. The process according to claim 1, whereing the heat shrinking seals at least 80% of the film handle to the wrapping film.

11. The process according to claim 3, wherein the static probe receives 20 KV@150 uA direct current from a power unit, further comprising: electrostatically bonding the handle strip to the wrapping film by applying 20 KV@150 uA current to either the handle strip film or the wrapping film.

12. The process according to claim 3, further comprising: receiving the handle strip film and the wrapping film in the static unit on a heat shrinking film wrapping machine, wherein the ground strap or bar is bonded to a frame of the heat shrinking film wrapping machine.