HK1196588A - Method for inserting a first folded film within a second folded film - Google Patents

Description

Method for inserting a first folded film into a second folded film

Technical Field

The present invention relates generally to webs and films. In particular, the present invention relates to a method of inserting one folded film or web into another folded film or web.

Background

Thermoplastic films are common elements in a variety of commercial and consumer products. For example, grocery bags, trash bags, sacks, and packaging materials are products that are typically made from thermoplastic films. In addition, feminine hygiene products, baby diapers, adult incontinence products, and a variety of other products to some extent include thermoplastic films.

Thermoplastic films have a variety of different strength parameters that manufacturers who incorporate thermoplastic film elements into products may attempt to manipulate to ensure that the film is suitable for its intended use. For example, a manufacturer may attempt to increase or otherwise control the tensile strength of a thermoplastic film. The tensile strength of a thermoplastic film is the maximum stress that the film can withstand while stretched before it fails. Another strength parameter that manufacturers may want to increase or otherwise control is tear resistance. The tear strength of a thermoplastic film is the amount of force required to propagate or propagate a crack that has been created in the film. Moreover, manufacturers may want to increase or otherwise control the impact strength of the film.

When forming various products from thermoplastic films, a manufacturer may fold the thermoplastic film in half (or otherwise create a folded film), and use the folded film to produce the products. For example, a manufacturer may create a bag using a folded film. Specifically, the manufacturer may seal the sides of the folded film adjacent the fold. The sealed sides and bottom creases may form three joined sides of the bag.

Unfortunately, conventional methods for combining folded films have various disadvantages that result in undesirable conditions. For example, conventional methods for combining folded films may require handling a significant machine width of the wide web, and a machine direction length of the folded film. In addition, conventional methods used to combine folded films can result in web handling and wrinkle problems, which are undesirable.

Accordingly, there are a number of considerations to be addressed in thermoplastic films and manufacturing processes.

Disclosure of Invention

Embodiments of the present invention provide benefits and/or address one or more problems in the art by way of methods for inserting a folded film into another folded film without first combining unfolded films and then folding them together. In addition, one or more embodiments provide methods for inserting a folded film into another folded film without any folding or unfolding during the insertion process. Thus, one or more embodiments may result in floor space savings during manufacture, thereby resulting in reduced capital costs.

For example, an embodiment of a method for inserting a second folded film into a first folded film may involve advancing the first folded film in a first direction of travel. The method may also involve advancing the second folded film in a second direction of travel that is not parallel to the first direction of travel. Additionally, the method may involve inserting a second folded film between the first half and the second half of the first folded film. Moreover, the method may involve redirecting the second folded film from the second direction of travel to the first direction of travel while between the first half and the second half of the first folded film.

Additionally, a method of producing a multi-layer thermoplastic bag may involve separating a first half and a second half of a first folded film. Further, the method may involve inserting a second folded film between the first half and the second half of the first folded film. The method may also involve changing a direction of travel of the second film while between the first half and the second half of the first folded film.

In addition to the above, a method for inserting a second folded film into a first folded film may involve advancing the first folded film in a first direction of travel in a first plane. The method may additionally involve advancing the second folded film in the first direction of travel in a second plane, and then redirecting the second folded film from the second plane to the first plane. The method may also involve separating the first half from the second half of the first folded film. The method may also involve advancing the second folded film in a second direction of travel between the first half and the second half of the first folded film. Moreover, the method may involve redirecting the second folded film from the second direction of travel to the first direction of travel while between the first half and the second half of the first folded film.

Additional features and advantages of exemplary embodiments of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of such exemplary embodiments. The features and advantages of such embodiments may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary embodiments as set forth hereinafter.

Drawings

In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It should be noted that the figures are not drawn to scale and elements of similar structure or function are generally represented by like reference numerals throughout the figures for illustrative purposes. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 illustrates a process and apparatus for inserting a folded film into another folded film in accordance with an embodiment of the present invention;

FIG. 2 illustrates another process and apparatus for inserting a folded film into another folded film in accordance with embodiments of the present invention;

FIG. 3 illustrates particular elements of an apparatus for insertion of a folded film into another folded film, in accordance with an embodiment of the present invention;

FIG. 4A illustrates a bag comprising a plurality of layers of synthetic pleated film according to one or more embodiments of the invention;

FIG. 4B shows a cross-sectional view of the pouch of FIG. 4A taken along line 4A-4A of FIG. 4A; and

FIG. 5 shows a schematic view of a bag manufacturing process according to one or more embodiments of the invention.

Detailed Description

One or more embodiments of the present invention include methods for inserting a folded film into another folded film without first combining the unfolded films and then folding them together. In addition, one or more embodiments provide a method of inserting a folded film into another folded film without any folding or unfolding during the insertion process. Thus, one or more embodiments may result in floor space savings during manufacture, thereby resulting in reduced capital costs.

In addition, one or more embodiments provide efficient systems and methods for combining folded films. Reducing process steps by eliminating the need to process the omentum may allow for improved reliability, and reduction or elimination of wrinkles in the product(s) being produced. In addition, one or more embodiments can effectively and efficiently combine folded films without sacrificing important material properties of the product, such as tear and puncture resistance.

In addition to the above, the systems and methods of one or more embodiments allow the folded films to undergo different cold forming transitions prior to assembly. For example, one or more embodiments allow a folded film to undergo different incremental stretching or other treatments that can increase the surface area and/or modify the physical properties of the film. After combination, the folded films can be laminated together to form a multilayer film with the same or better properties using less material than a single layer or coextruded multilayer film.

Film material

As a preliminary matter, embodiments of the present invention are described herein primarily with reference to the handling and combining of thermoplastic films or webs. It will be appreciated, however, that a thermoplastic film or web is merely one type of "structure" that a user may handle using the elements, systems, and methods described herein. For example, a user may use embodiments of the present invention to insert one folded layer into another folded layer of not only a thermoplastic film such as this, but also paper, woven or non-woven fabric, or other structures. Accordingly, reference herein to a thermoplastic film or web as such is primarily for descriptive convenience.

The thermoplastic material of the film of one or more embodiments may include, but is not limited to, thermoplastic polyolefins including polyethylene and copolymers thereof, and polypropylene and copolymers thereof. The olefin-based polymer may include: most common ethylene or propylene based polymers such as polyethylene, polypropylene, and copolymers such as Ethylene Vinyl Acetate (EVA), Ethylene Methyl Acrylate (EMA), and Ethylene Acrylic Acid (EAA); or a mixture of such polyolefins.

Other examples of polymers suitable for use as films according to the present invention include elastomeric polymers. Suitable elastomeric polymers may also be biodegradable or environmentally degradable. Suitable elastomeric polymers for the film include poly (ethylene-butene), poly (ethylene-hexene), poly (ethylene-octene), poly (ethylene-propylene), poly (styrene-butadiene-styrene), poly (styrene-isoprene-styrene), poly (styrene-ethylene-butylene-styrene), poly (ester-ether), poly (ether-amide), poly (ethylene-vinyl acetate), poly (ethylene-methyl acrylate), poly (ethylene-acrylic acid), poly (ethylene-butyl acrylate), polyurethane, poly (ethylene-propylene-diene), ethylene-propylene rubber.

Indeed, embodiments of the present invention may comprise any flexible or pliable thermoplastic material that may be formed or drawn into a web or film. Further, the thermoplastic material may comprise a single layer or multiple layers. Examples of multilayer films suitable for use with one or more embodiments of the present invention include extruded multilayer films, films that are laminated together in series, and films that are laminated together partially or intermittently. The thermoplastic material may be opaque, transparent, translucent, or tinted. Furthermore, the thermoplastic material may be breathable or non-breathable.

As used herein, the term "flexible" refers to materials that are capable of flexing or bending, particularly repeatedly, such that they are pliable and yieldable in response to an externally applied force. Accordingly, "flexible" is generally in the opposite sense to the terms inflexible, rigid, or unyielding. Materials and structures that are flexible can thus change shape and structure to accommodate external forces and conform to the shape of objects that are brought into contact with them without losing their integrity. According to another prior art material, web materials are provided which exhibit "elastic-like" properties in the direction of applied tension without the use of added traditional elasticity. As used herein, the term "elastomeric-like" describes the properties of the web material that, when subjected to an applied tension, extend in the direction in which the tension is applied, and when the applied tension is released, the web material returns to some degree to their pre-tensioned state.

In addition to the foregoing, it will be appreciated in light of the disclosure herein that manufacturers may form films or webs for use with the present invention using a variety of techniques. For example, a manufacturer may form a film using conventional flat or cast extrusion or coextrusion that produces single, dual, or multi-layer films. Alternatively, the film may be formed by a manufacturer using a suitable process, such as a blown film process for producing a single layer, double layer, or multilayer film. If desired for a given end use, the manufacturer may orient the film through trapped air bubbles, tenter frames, or other suitable processes. In addition, the manufacturer may thereafter selectively toughen the film.

In one or more embodiments, the film of the present invention is a blown film, or a cast film. Blown films and cast films are formed by extrusion. The extruder used can be a conventional extruder using a die that will provide the desired dimensions. Some useful extruders are described in U.S. Pat. Nos. 4,814,135, 4,857,600, 5,076,988, 5,153,382, each of which is incorporated herein by reference. Examples of the various extruders that may be used in producing the film for use in the present invention may be single screw types modified with respect to blown film dies, air rings, and continuous stripping equipment.

In the blown film process, the mold can be a vertical cylinder with an annular opening. The rollers may pull the molten plastic upward away from the mold. As the film travels upward, the air ring may cool the film. The air outlet may force compressed air into the center of the extruded annular profile, creating a bubble. The air can expand the extruded circular cross-section by many times the die diameter. This ratio is called the "blow-up ratio".

The film may be formed into a folded film or web, such as a c-folded film and web, or a u-folded film or web. Such folded films and webs may be formed by stacking and then cutting annular tubes of film formed using a blown film process. Specifically, the annular tube may be cut in half to form two folded films (which are mirror images of each other). In another process, the folded film may be formed by mechanical folding of the film.

The film of one or more embodiments of the present invention may have a starting dimension of between about 0.1 mil and about 20 mil, suitably from about 0.2 mil to about 4 mil, suitably in the range of about 0.3 mil to about 2 mil, suitably from about 0.6 mil to about 1.25 mil, suitably from about 0.9 mil to about 1.1 mil, suitably from about 0.3 mil to about 0.7 mil, and suitably from about 0.4 mil and about 0.6 mil. In other embodiments, the starting dimension of the film may be greater than about 20 mils. In addition, the starting dimensions of the film of one or more embodiments of the present invention may be non-uniform. Thus, the starting dimension of the film of one or more embodiments may vary along the length and/or width of the film.

It may be useful and advantageous to combine two or more folded films by inserting one folded film into another such that the folded edges of the composite film coincide and the open edges of the folded films coincide. Such films can be used to form multi-layer bags that have no seams along the bottom of the bag. Instead of seams, folds of the film may form the bottom of the bag.

Referring now to the drawings, FIG. 1 illustrates an exemplary process and apparatus for inserting a folded film into another folded film, according to embodiments of the present invention. Specifically, fig. 1 illustrates an insertion process that inserts one folded film 10 into another folded film 20 and produces a multilayer composite 30. As shown, the folded film 10 may include a folded edge 12, an open edge 14, a first half 16, and a second half 18. Similarly, the folded film 20 can include a folded edge 22, an open edge 24, a first half 26, and a second half 28. Thus, as shown, each of the folded films 10, 20 may include a "c", "j", or "u" shaped configuration. Thus, the folded films 10, 20 may be referred to herein as c-folded, j-folded, or u-folded films. c-folded films may include films that are symmetric about their folded edges, while j-or u-folded films may include films that are asymmetric about their folded edges (i.e., one of the halves extends farther than the other half).

Fig. 1 also illustrates the creation of a multilayer composite folded film 30. Creating the multilayer composite folded film 30 includes folding the film 10 with the folded film 10 inserted into the folded film 20. Specifically, the folded film 10 is positioned between the first half 26 and the half 28 of the folded film 20. The resulting multilayer composite folded film 30 has a folded edge 32 and an open edge 34. The folded edges 12 and 22 of the folded films 10 and 20 coincide with the folded edge 32 of the resulting multilayer composite folded film 30. Correspondingly, the open edges 14 and 24 of the folded films 10 and 20 coincide with the open edge 34 of the resulting multilayer composite folded film 30.

As explained in more detail below, the folded film insertion process of the present invention can produce a multilayer composite folded film that can include properties of both the folded film 10 and the folded film 20. Such a combination of the properties of the two synthetic folded films has a beneficial effect in the resulting composite and on products, such as trash or food bags, which are manufactured from the synthetic folded films. In addition, the processes and apparatus disclosed herein may provide benefits in manufacturing processes used to produce synthetic folded films by reducing the time, floor space, and complexity of inserting one folded film into another folded film. The reduction in time, floor space, and complexity used to insert one folded film into another folded film may in turn result in high efficiency and cost savings for the production of the films and products.

To produce the multilayer composite folded film 30, the manufacturer may advance the folded film 20 in the first direction of travel 36. In one or more embodiments, the first direction of travel 36 may be parallel to the machine direction, or in other words, parallel to the direction of the extruded, folded film 20. While traveling in the first direction of travel 36, the manufacturer may separate the first half 26 from the second half 28 of the folded film 20. For example, the folded film 20 may be passed around the spreader bar 38. The spreader bar 38 may unfold the folded film 20. For example, fig. 1 shows that the spreader bar 38 can separate the first half 26 from the second half 28 of the folded film 20, thereby creating a gap between the first and second halves 26, 28. Specifically, the first half 26 of the folded film 20 may pass on one side of the spreader bar 38, and the second half 28 of the folded film 20 may pass on the opposite side of the spreader bar 38.

The spreader bar 38 may be made of cast and/or machined metal, such as steel, aluminum, or any other suitable material. Alternatively, the spreader bar 38 may be coated with a material such as rubber or urethane. Also, the spreader bar 38 may optionally have an air bearing assist or plasma coating to reduce friction. The spreader bar 38 may extend in a direction 40. In one or more embodiments, the direction 40 may be transverse or perpendicular to the first direction of travel 36. Thus, in one or more embodiments, the spreader bar 38 can extend in a direction transverse to the machine direction. The spreader bar 38 can have any configuration that allows for separation of the first and second halves 26, 28 of the folded film 20. For example, as shown in FIG. 1, the spreader bar 38 may have a tapered leading edge. In alternative embodiments, the spreader bar 38 may have a cylindrical or other shape.

Fig. 1 also shows that the manufacturer may advance the folded film 10 in the second direction of travel 42. The second direction of travel 42 may be non-parallel to the first direction of travel 36. For example, in one or more embodiments, the second direction of travel 42 may be transverse or perpendicular to the first direction of travel 36. The manufacturer may also insert the folded film 10 between the separate halves 26, 28 of the folded film 20. For example, the manufacturer may advance the folded film 10 in the second direction of travel 42 between the first half 26 and the second half 28 of the folded film 20.

Once within the folded film 20, the manufacturer may redirect the folded film 10 from the second direction of travel 42 to the first direction of travel 36. Specifically, the folded film 10 may change direction from the second direction of travel 42 to the first direction of travel 36 while between the first and second layers 26, 28 of the folded film 20. For example, the folded film 10 may pass around a turning bar or roller 44. The direction change bar 44 changes the traveling direction of the folded film 10. More specifically, the folded film 10 may initially pass over a first side of the direction change bar 44 and then pass around the direction change bar 44 so the folded film 10 is moved away from a second, opposite side of the direction change bar 44.

It will be appreciated in view of the disclosure herein that the direction change lever 44 can include a variety of different configurations. For example, FIG. 1 shows that the direction change lever 44 can comprise a cylinder. In alternative embodiments, the direction-changing bar 44 may be a flat bar with tapered edges, or may be a roller with a rolling direction to accommodate the direction of travel of the folded film 10. Thus, in the embodiment shown in fig. 1, the direction change lever 44 is rotatable in the clockwise direction. The direction change bar 44 may be made of cast and/or machined metal, such as steel, aluminum, or any other suitable material. Alternatively, the direction change lever 44 may be coated with a material such as rubber or urethane. Also, the direction change lever 44 may optionally have an air bearing assist or plasma coating to reduce friction.

FIG. 1 shows that the direction change bar 44 may be coplanar with the spreader bar 38. The coplanar configuration of the spreader bar 38 and direction change bar 44 may allow the direction change bar 44 to change the orientation of the folded film 10 while within the folded film 20. As also shown in fig. 1, the direction change bar 44 may extend in a direction 46. Direction 46 may extend at an acute angle relative to direction 40. For example, direction 46 may extend at a 45 degree angle relative to direction 40. In other words, the direction change bar 44 may extend at an angle of 45 degrees relative to the spreader bar 38. Thus, the direction change lever 44 can achieve a 90 degree change in the traveling direction of the folded film 10 as the folded film 10 passes over the direction change lever 44. In other words, after passing around the direction-changing bar 44, the folded film 10 may travel in a direction perpendicular to the second direction of travel 42.

After the folded film 10 passes over the diverter bar 44, the folded film 10 is then positioned between the first and second layers 26, 28 of the folded film 20 (i.e., the folded film 10 has been inserted into the folded film 20), resulting in a multi-layer composite folded film 30. As previously mentioned, the multilayer synthetic folded film 30 has a folded edge 32 and an open edge 34. The folded edges 12 and 22 of the folded films 10, 20 coincide with the folded edge 32 of the resulting multilayer composite folded film 30. Correspondingly, the open edges 14 and 24 of the folded films 10 and 20 coincide with the open edge 34 of the resulting multilayer composite folded film 30.

One or more embodiments may also include an applicator that applies an additive to one or more of the halves 16, 18, 26, 28 of the folded films 10, 20. For example, fig. 1 shows a spreader bar 38, which spreader bar 38 may have an integrated applicator. The integrated applicator may include a plurality of openings 48, and the plurality of openings 48 may dispense or spray the additive onto the inner surface of the folded film 20 as the folded film 20 passes around the spreader bar 38. As explained in more detail below, in an alternative embodiment, a separate applicator may reside between the spreader bar 38 and the direction change bar 44.

In any case, the applicator may apply the additive to one or more of the folded films 10, 20. Such additives may include gums, adhesives, oils, fragrances, or other additives. For example, in one or more embodiments, the applicator may apply glue or another adhesive to the inner surface of the folded film 20 and/or the outer surface of the folded film 10. After inserting the folded film 10 into the folded film 20, the glue may then adhere or laminate the inner surface of the folded film 20 to the outer surface of the folded film 10.

Fig. 1 shows a c-folded film 10 with the c-folded film 10 inserted within another c-folded film 20. In one or more embodiments, the process and apparatus described with respect to fig. 1 may be repeated to combine three or more folded films or one or more folded films with one or more single-layer films. For example, in one or more embodiments, another spreader bar, similar to the spreader bar 38, can separate the first half 16, 26 from the second half 18, 28 of the multilayer composite folded film 30. The manufacturer may then direct the additional film (either the single layer film or another folded film) in the second direction of travel 42. The process may then include inserting an additional film between the first half 16, 26 and the second half 18, 28 of the folded films 10, 20. Once within the first and second halves, the process may include redirecting the third film from the second direction of travel 42 to the first direction of travel 36. Specifically, the third film may pass around a direction change bar similar to the direction change bar 44.

In addition to the above, one or more embodiments may also include abutting the folded edge 12 of the folded film 10 against the folded edge 22 of the folded film 20. For example, FIG. 1 shows that once the folded film 10 is inserted into the folded film 20, the manufacturer can separate the first half 16 from the second half 18 of the folded film 10. For example, the folded film 10 may be passed around a creasing rod 45. The creasing rod 45 may unfold the folded film 10. For example, fig. 1 shows that the tucker bar 45 may separate the first half 16 from the second half 18 of the folded film 10, thereby creating a gap between the first and second halves 16, 18. Specifically, the first half 16 of the folded film 10 may pass on one side of the creasing bar 45, and the second half 18 of the folded film 10 may pass on the opposite side of the creasing bar 45.

The crumple bars 45 may be made of cast and/or machined metal, such as steel, aluminum, or any other suitable material. Alternatively, the crumple bar 45 may be coated with a material such as rubber or urethane. Also, the crumple bar 45 may optionally have an air bearing assist or plasma coating to reduce friction. The crumple bar 45 may extend in the direction 40. The tucker bar 45 may have any configuration that allows separation of the first and second halves 16, 18 of the folded film 10. For example, as shown in fig. 1, the crumple bar 45 may have a tapered leading edge. In alternative embodiments, the crumple bar 45 may have a cylindrical or other shape.

The ends of the crumple bar 45 may include rollers 47. In one or more embodiments, the arm 49 may position the roller 47 downstream of the crumple bar 45. In alternative embodiments, the roller 47 may be in line with the creasing rod 45, or on a separate rod downstream of the creasing rod 45. In any case, the roller 47 may reside between the first and second halves 16, 18 of the film stack 10 separated by the tucker bar 45. The roller 47 may rotate and push the folded edge 12 of the folded film 10 toward the folded edge 22 of the folded film 20. For example, in one or more embodiments, the roller 47 may push or otherwise position the folded edge 12 of the folded film 10 against the folded edge 22 of the folded film 20.

Alternatively, the roller 47 may be coated with a material such as rubber or urethane. Also, the roller 47 may optionally have an air bearing assist or plasma coating to reduce friction. In one or more embodiments, the roller 47 may be configured to ensure that it does not tear or otherwise tear either of the folded films 10, 20. For example, the roller 47 can be spring loaded. Alternatively, or in addition, the sensor may monitor the force exerted by the roller 47 on the folded films 10, 20. The actuator may automatically adjust one or more of the position of the roller 47, the speed of the roller 47, or other parameters in response to the sensor to reduce the likelihood or prevent damage to the film by the roller 47.

Fig. 1 shows an embodiment in which the folded film 10 and the folded film 20 arrive at the process and apparatus in a vertical direction. To reduce manufacturing space, in one or more embodiments, folded film 10 and folded film 20 arrive in a direction other than the vertical direction. For example, fig. 2 shows an apparatus and method for inserting a folded film into another folded film, in which both folded films 10, 20 begin the process by advancing in a first direction of travel 36.

As shown in fig. 2, the guide roller 50 guides the folded film 10 in the first traveling direction 36. Similarly, the auxiliary guide rollers 52 may guide the folded film 20 in the first direction of travel 36. Each of guide rollers 50, 52 may extend in direction 40. The guide rollers 50, 52 may each have a generally cylindrical shape. The guide rolls 50 and 52 may be made of cast and/or machined metal, such as steel, aluminum, or any other suitable material. The guide rollers 50 and 52 are rotatable in corresponding directions about parallel axes of rotation.

Guide roller 50 and folded film 10 may reside out of plane with guide roller 52 and folded film 20. For example, fig. 2 shows that guide roller 50 may reside vertically above guide roller 52. It will be appreciated that running the folded films 10, 20 vertically on top of each other can reduce the footprint of the folded film assembly apparatus. In an alternative embodiment, guide roll 50 and folded film 10 may reside in the same plane as guide roll 52 and folded film 20.

After passing from the roller 50, the manufacturer may redirect the folded film 10 from the first direction of travel 36 to the third direction of travel 54. Specifically, the folded film 10 is redirected from the first direction of travel 36 to the third direction of travel 54 by passing around a direction change bar or roller 56. The direction change lever 56 can change the traveling direction of the folded film 10 in a manner similar to that of the direction change lever 44. Further, the direction changing lever 56 may have a configuration similar to that of the direction changing lever 44. More specifically, the folded film 10 may initially pass over a first side of the direction change bar 56 and then pass around the direction change bar 56 so the folded film 10 is moved away from a second, opposite side of the direction change bar 56.

Fig. 2 shows that the direction change lever 56 may be coplanar with the guide roller 50. Further, the direction change bar 56 may reside out of plane with the direction change bar 44. For example, fig. 2 shows that the direction change lever 56 may reside vertically above the direction change lever 44.

Fig. 2 also shows that the direction-changing lever 56 can extend in the direction 58. Direction 58 may extend at an acute angle relative to direction 40. For example, direction 58 may extend at a 45 degree angle relative to direction 40. In other words, the direction change lever 56 may extend at an angle of 45 degrees with respect to the guide roller 50. In one or more embodiments, the direction change bar 56 may extend in a direction 58 perpendicular to the direction 46, with the direction change bar 44 extending in the direction 46. In any case, the direction-changing lever 56 can effect a change in the direction of travel of the folded film 10 as the folded film 10 passes over the direction-changing lever 56, so that the folded film 10 travels in a direction perpendicular to the first direction of travel 36 after passing around the direction-changing lever 56.

One or more orientation rollers may then direct the folded film 10 to the same plane as the folded film 20. For example, FIG. 2 shows that the orientation roller 60 can redirect the folded film 10 from a planar to a vertical plane. Specifically, the orientation roller 60 may redirect the folded film 10 from traveling in a horizontal plane to a vertical plane. The orientation roller 60 may extend in a direction 62 perpendicular to the direction 40. In addition, the direction roller 60 may be located in the same plane as the direction change lever 56.

After passing from the orientation roller 60, the folded film 10 may pass around another orientation roller 64. The orientation roller 64 may redirect the folded film 10 from a planar to a vertical plane. Specifically, the orientation roller 64 may redirect the folded film 10 from traveling in a vertical plane to a horizontal plane. As shown in fig. 2, the orientation roller 64 may direct the folded film 10 into the second direction of travel 42. The orientation roller 64 may extend in the direction 62. In addition, the direction roller 64 may be located in the same plane as the direction change lever 44.

The manufacturer may then insert the folded film 10 between the separate halves 26, 28 of the folded film 20, as described above. Once within the folded film 20, the manufacturer may redirect the folded film 10 from the second direction of travel 42 to the first direction of travel 36. In particular, the folded film 10 may pass around a direction-changing bar or roller 44, as described above. After the folded film 10 passes over the diverter bar 44, the folded film 10 is then positioned between the first and second layers 26, 28 of the folded film 20 (i.e., the folded film 10 has been inserted into the folded film 20), resulting in a multi-layer composite folded film 30.

As shown in fig. 2, the folded edge 12 and the open edge 14 of the folded film 10 may change sides within and during the process. As the folded film 10 travels in the first direction of travel 36, the folded edge 12 is at the "front" of fig. 2 and the open edge 14 is at the "rear" of fig. 2. As the folded film 20 travels in the first direction of travel 36 on the other hand, the folded edge 22 is at the "back" of fig. 2 and the open edge 24 is at the "front" of fig. 2. Thus, the folded film 10 and the folded film 20 may enter the apparatus in opposite orientations. By passing around the orientation rollers 60, 64 and the direction change bar 44, the open edge 14 of the folded film 10 can be changed to the "front" of FIG. 2, and the folded edge 12 can be changed to the "rear" of FIG. 2. As the multilayer composite folded film 30 emerges from the apparatus and process, the folded edge 12 of the folded film 10 coincides with the folded edge 22 of the folded film 20, and the open edge 14 of the folded film 10 coincides with the open edge 24 of the folded film 20.

The system and apparatus of fig. 2 does not include the crumple bar 45 and the roller 47. It will be appreciated in view of the disclosure herein that the tucker bar 45 and the roller 47 may be added to the system and apparatus of fig. 2, and/or any of the other devices, systems, and methods described herein. For example, in one or more embodiments, the system and apparatus of fig. 2 may include a crumple bar 45 and a roller 47, the crumple bar 45 and roller 47 being positioned downstream of the direction change bar 44.

Fig. 3 illustrates another embodiment of an apparatus for inserting a first folded film into a second folded film. The apparatus of fig. 3 is similar to the apparatus of fig. 2, albeit oriented vertically. It will be appreciated in view of the disclosure herein that the vertical orientation of the apparatus of fig. 3 may further reduce the footprint of the apparatus and save manufacturing space. As shown in FIG. 3, in one or more embodiments, the spreader bar 38, the direction change bar 44, the guide roller 52, and the orientation roller 64 are positioned in the same vertical plane. The direction change lever 56 and the guide roller 50 are positioned in a second vertical plane that is horizontally offset from the first vertical plane.

Fig. 3 omits the folded film 10 and the folded film 20 to make the illustrated elements more easily visible and understandable. Line 66 shows the path of the folded film 10 and line 68 shows the path of the folded film 20. Line 70 on the other hand illustrates the path of the multilayer composite folded film 30.

Fig. 3 shows guide rollers 50 and 52, which guide rollers 50 and 52 receive the folded film 10 and the folded film 20, respectively. The guide roller 50 may guide the folded film 10 along a path 66 to the direction change bar 56. The guide roller 52 may guide the folded film 20 along a path 68 to the spreader bar 38. The apparatus may also include brackets or struts 71, 72 that support one or more of the rollers or rods 38, 44, 56, 74 with the brackets or struts 71, 72. For example, fig. 3 shows that the support column 71 can support the direction-changing lever 56. Similarly, the support post 72 may support the spreader bar 38, the direction change bar 44, and the applicator 74.

As previously mentioned, one or more embodiments may include an applicator positioned between the spreader bar 38 and the direction change bar 44. For example, fig. 3 shows an applicator 74, which applicator 74 is positioned in line with the spreader bar 38 and the direction-changing bar 44, and is positioned between the spreader bar 38 and the direction-changing bar 44. Similar to the integrated applicator in the spreader bar of fig. 1, the applicator 74 may apply the additive to one or more of the halves 16, 18, 26, 28 of the folded films 10, 20. Such additives may include gums, adhesives, oils, fragrances, or other additives. For example, in one or more embodiments, the applicator may apply glue or another adhesive to the inner surface of the folded film 20. After inserting the folded film 10 into the folded film 20, the glue may then adhere or laminate the inner surface of the folded film 20 to the outer surface of the folded film 10.

In an alternative embodiment, the apparatus may include one or more applicators that apply the additive to the folded film 10. For example, a pair of applicators may extend above and below the folded film 10 and spray the additive onto the outer surface of the folded film 10. In one or more embodiments, the apparatus can include such an applicator between the directional roller 64 and the direction change bar 44.

1-3, it is possible that one or more embodiments of the invention may include some, all, or additional elements shown in FIGS. 1-3. For example, fig. 3 shows that the orientation roller 60 may be omitted. Specifically, the orientation roller 64 may receive the folded film 10 after the folded film 10 leaves the direction change bar 56. The orientation roller 64 may then direct the folded film to the direction change bar 44.

In further additional embodiments, one or more orientation rollers and direction change levers may transition the folded film 20 to the same plane as the folded film 10. This is in contrast to FIG. 2, which shows one or more orientation rollers and direction-changing levers that transition the folded film 10 to the same plane as the folded film 20. Such variations and alternative constructions are consistent with and contemplated by the present invention. Moreover, such alternative configurations may accommodate devices of various sizes consistent with the present invention, and devices and/or processes employed in different and various situations. Accordingly, the elements and descriptions herein should not be read as limiting, and all variations and embodiments consistent with this description are to be considered within the scope of the invention.

It will be appreciated in view of the disclosure herein that the multilayer synthetic folded film may form part of any type of product made from or including thermoplastic film. For example, grocery bags, trash bags, sacks, packaging materials, feminine hygiene products, baby diapers, adult incontinence products, sanitary napkins, bandages, food storage bags, food storage containers, heat wraps, masks, wipes, hard surface cleaners, and a variety of other products can include a multilayer synthetic folded film. By inserting one folded film into another, a multilayer composite folded film can be produced that includes beneficial, but possibly different, properties of each of the individual folded films of the multilayer composite folded film. Trash bags and food storage bags may be particularly beneficial with the multilayer synthetic folded film of the present invention.

Referring to FIG. 4A, in an embodiment of the present invention, the multilayer synthetic folded film 30 shown in FIG. 1 may be included in a bag construction. The bag 100 may include a bag body 102, the bag body 102 being formed from one piece of multi-layer synthetic folded film. The bag bottom 112 may coincide with the folded edge 32 of the multilayer composite of folded films. The side seams 110 and 120 may bond the sides of the bag body 102 together to form a semi-enclosed container having an opening 140 along the open edge 114 (which corresponds to the open edge 34 of the multi-layer synthetic folded film 30). The bag 100 also optionally includes a closure device 150, the closure device 150 being disposed adjacent the open edge 114 for sealing the top of the bag to form a fully enclosed container or reservoir. The bag 100 is suitable for containing and protecting a wide variety of materials and/or objects. Closure device 150 may include a flap, adhesive tape, hem and crease closure, interlocking closure, slide closure, zipper closure, or other closure structure known to those skilled in the art for closing bags.

As represented by fig. 4B, folding the first halves 16, 26 of the films 10, 20 may form a first sidewall 152. The second half 18, 28 of the folded films 10, 20 may form a second sidewall 154. The seal may engage the edges (i.e., the folded edges 32) of the first and second halves 16, 26, 18, 28 adjacent the bottom of the bag. The combination of the properties of the folded films 10, 20 in the pouch created from the multi-layer synthetic folded film 30 may increase tear and impact strength and may help prevent the pouch created from the multi-layer synthetic folded film 30 from tearing and losing its contents.

Fig. 5 shows an exemplary embodiment of a manufacturing process 200 for inserting a folded film into another folded film and producing a plastic bag therefrom. According to this process, the folded film 10 is unwound from the winding roll 201 and guided along the direction of travel 36. The direction of travel 36 may be in the machine direction. The second folded film 20 is unwound from the roll 202 and guided in the direction of travel 36.

The folded film 10 may be selectively passed between the first and second intermeshing rollers 204, 206 to expand the folded film 10. Similarly, the folded film 20 may selectively pass between the third and fourth intermeshing rollers 208, 210. Expanding the folded film 10, 20 may modify and/or increase one or more of the physical properties of the folded film 10, 20 and/or increase the surface area of the folded film 10, 20 and/or decrease the dimensions of the folded film 10, 20. In addition, expanding the folded films 10, 20 may provide the folded films 10, 20 with a visible pattern that may be used to notify the customer that the folded film 10 has been treated to improve one or more properties.

The intermeshing rolls 204, 206, 208, 210 can be machine-direction ring rolls, cross-direction ring rolls, diagonal-direction ring rolls, Structured Elastic Like Film (SELF) rolls, embossing rolls, or other intermeshing rolls. Intermeshing rollers 204, 206, 208, 210 may be arranged with their longitudinal axes perpendicular to the machine direction. Additionally, the intermeshing rollers 204, 206, 208, 210 may rotate about their longitudinal axes in opposite rotational directions. In various embodiments, motors may be provided that supply rotational power to the intermeshing rollers 204, 206, 208, 210 in a controlled manner. The ridges and/or teeth of the intermeshing rollers 204, 206, 208, 210 may stretch the folded film 10, 20 as the folded film 10, 20 passes between the intermeshing rollers 204, 206, 208, 210.

A number of U.S. patents have been issued for expanding thermoplastic films and laminates. An early example of patented technology that discloses a method of expanding a film is U.S. Pat. No.5,296,184. Other related patents relating to incremental stretching of thermoplastic films and laminates include U.S. Pat. Nos. 6,265,045, 6,214,147, 6,013,151, 5,865,926, 5,861,074, 5,851,937, 5,422,172, 5,382,461, 5,518,801, 6,139,185, 6,150,647, 6,394,651, 6,394,652, 6,513,975, 6,695,476; and U.S. patent application publication nos. 2004/0134923 and 2006/0093766.

Additionally or alternatively, for incremental stretching, the process 200 may include orienting the folded films 10, 20. For example, process 200 may include Machine Direction Orientation (MDO) of the folded film by passing the folded film between two pairs of smooth rollers. The nip of the first pair of rollers, which are running at a relatively slow speed, can pinch the folded film 10, 20. The nip of the second pair of rollers downstream of the first pair then pinches the folded film 10, 20, which second pair of rollers is operating faster than the first pair. Because of the difference in operating speeds, the film between the roller pairs must either stretch or break to accommodate the difference.

The ratio of the roll speeds will generally determine the amount of film stretch. For example, if the first pair is operating at 100 feet per minute (fpm) and the second pair is operating at 300fpm, the film will stretch to approximately three times its original length. The MDO process stretches the film continuously only in the Machine Direction (MD). The MDO method is used to create MD oriented films. Optionally, the process 200 may include tentering the folded films 10, 20. Most simply, the tentering process involves grasping the side portions of the film and stretching it laterally.

In any event, it will be recognized in view of the disclosure herein that one or more embodiments of the process and apparatus for inserting a folded film into another folded film may allow for independent stretching or orientation of the folded films 10, 20. Thus, the process 200 may include folding the film 10 to different degrees of stretch or orientation, or using different techniques in addition to the stretching or orientation of the folded film 20. Combinations of films of different orientation and/or type or degree of stretch may allow for rebalancing or other modification of film properties. In one or more embodiments, the resulting properties of the multilayer synthetic folded film 30 may be additional or otherwise enhanced based on the different properties of each of the folded films 10, 20.

During the manufacturing process 200, the folded films 10, 20 may also pass through nip roller pairs 212, 214, 216, 218. Nip rollers 212, 214, 216, 218 may be suitably arranged to pinch the folded films 10, 20. Nip rollers 212, 214, 216, 218 may facilitate and accommodate folding of the films 10, 20.

The insertion operation 220 may then insert the folded film 10 into the folded film 20. The inserting operation 220 may combine the folded films 10, 20 using any of the apparatus and methods described herein above with respect to fig. 1-3. In one or more embodiments, the inserting operation 220 can also laminate the folded films 10, 20 together (i.e., when the inserting operation 220 includes an applicator that applies glue or other adhesive to one or more of the folded films 10, 20).

Optionally, the process 200 may include a separate lamination operation 222. The laminating operation 222 may continuously or intermittently laminate the folded films 10, 20 together. By verb, "lamination" is meant the attachment or bonding (by means of, for example, adhesive bonding, pressure bonding, ultrasonic bonding, corona lamination, etc.) of two or more separate fabricated film articles to each other, thereby forming a multilayer structure; by the term "laminated" is meant a product produced by the attachment or bonding just described. Thus, in one or more embodiments, the laminating operation 222 can include laminating the folded films 10, 20 together by passing the folded films 10, 20 through a machine-direction ring roll, a cross-direction ring roll, a diagonal-direction ring roll, a SELF roll, an embossing roll, or other intermeshing rolls.

The processing equipment may also process the multi-layer composite folded film 30 after the multi-layer composite folded film 30 emerges from the inserting and/or laminating operations 220, 222 in order to produce the finished bag. Specifically, the draw tape operation 224 may insert the draw tape 226 into the composite folded film 30 at the open edge 34. In addition, the sealing operation 228 may form the parallel side edges of the finished bag by forming heat seals 230 between adjacent portions of the multilayer synthetic folded film 30. The heat seals 230 may be incrementally spaced along the multilayer composite folded film 30. The sealing operation 228 may use a heating device, such as a heating knife, to form the heat seal 230.

Perforation operation 232 may form perforations 234 in heat seal 230 using a perforation device, such as a perforation knife. The perforations 234 along with the folded edge 32 may define individual pockets 238, and these individual pockets 238 may be separated from the modified synthetic folded film 30. A roll or reel 240 may be wound with the modified synthetic folded film 30, embodiment finished bags 238 for packaging and dispensing. For example, the roll 240 may be placed into a box or bag for sale to a customer.

In other embodiments, the multilayer synthetic folded film 30 may be cut into individual pouches along the heat seal 230 by a cutting operation 236. In another embodiment, the multilayer synthetic folded film 30 may be folded one or more times prior to the cutting operation 236. In yet another embodiment, the side sealing operation 228 may be combined with the cutting and/or perforating operations 232, 236.

It will be recognized in light of the disclosure herein that process 200 described with respect to fig. 5 can be modified to omit or augment various actions, or to alter the order of various actions, as desired. For example, two or more separate films or folded films may be inserted within the folded film 20 during the inserting operation 220. In one or more additional embodiments, the folded films 10, 20 may not be oriented or stretched. In still further embodiments, the multilayer synthetic folded film 30 may be oriented or stretched.

Embodiments of the present invention may also include a method of inserting a folded film into another folded film. At least one embodiment of the method is described below with reference to the elements and figures of fig. 1-5. Of course, as a preliminary matter, one skilled in the art will recognize that the methods explained in detail herein can be modified to create a wide variety of configurations using one or more elements of the present invention. For example, various acts of the described methods may be omitted or augmented, and the order of the various acts of the described methods may be changed, as desired.

For example, a method according to one or more embodiments of the present invention may involve advancing the folded film 20 in a first plane in a first direction of travel 36. The method may also involve advancing another folded film 10 in a second plane in the first direction of travel 36. The first and second planes may be offset vertical planes or vertically offset horizontal planes.

The method may also involve redirecting the folded film 10 from a first plane to a second plane. For example, the method may involve redirecting the folded film 10 from the first direction of travel 36 to another direction of travel 54, the other direction of travel 54 being perpendicular to the first direction of travel 36. In particular, the method may involve passing the folded film 10 around a direction change bar 56. The method may then involve passing the folded film 10 around one or more directional rollers 60, 64, the one or more directional rollers 60, 64 redirecting the folded film from the first plane to the second plane, and from the direction of travel 54 to the direction of travel 42, the direction of travel 42 being opposite the direction of travel 54.

The method may additionally involve separating the halves of the folded film 20. For example, the method may involve passing the folded film 20 around the spreader bar 38. Specifically, the first half 26 may pass on one side of the spreader bar 38, while the second half 28 of the folded film 20 may pass on the opposite side of the spreader bar 38. Optionally, the method may also involve directing the additive out of the spreader bar 38 and onto the folded film 20.

The method may also involve inserting the folded film 10 into the folded film 20. For example, the method may involve advancing the folded film 10 between the first half 26 and the second half 28 of the folded film 20. The method may also involve redirecting the folded film 10 from the direction of travel 42 to the direction of travel 36 while between the first half 26 and the second half 28 of the folded film 20. For example, the method may involve passing the folded film 10 around a direction-changing bar 44, the direction-changing bar 44 being located between the first half 26 and the second half 28 of the folded film 20.

1-5 and the corresponding text, therefore, expressly represent, describe, or otherwise provide various systems, elements, apparatuses, and methods for inserting a folded film into another folded film to create a multilayer composite folded film. These apparatus and methods can insert a folded film into another folded film to create a multilayer composite folded film that has the beneficial effect of the properties of the two folded films.

There are several advantages associated with multilayer synthetic folded films created in accordance with one or more embodiments of the present invention. The methods and apparatus described herein allow for independent cold forming of each folded film or ply. The methods and apparatus described herein result in floor space savings during manufacture, thereby resulting in reduced capital costs. The methods and apparatus described herein disclose a simpler process design than previously available, resulting in better reliability due to the reduction of required process steps, and fewer wrinkles in the resulting product(s) because individual folding and unfolding of the web is not required. Because the methods and apparatus described herein may reduce the time and complexity used to insert a folded film into another folded film, manufacturers may reduce the cost of their products if they use one or more of the methods and apparatus described herein. These cost savings can be significant.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (10)

1. A method for inserting a second folded film into a first folded film, the method comprising:

advancing a first folded film in a first direction of travel;

advancing a second folded film in a second direction of travel that is non-parallel to the first direction of travel;

inserting a second folded film between the first half and the second half of the first folded film; and

the second folded film is redirected from the second direction of travel to the first direction of travel while the second folded film is between the first half and the second half of the first folded film.

2. The method of claim 1, further comprising separating the first half and the second half of the first folded film prior to inserting the second folded film between the first and second halves of the first folded film.

3. The method of claim 2, further comprising passing the first folded film around a spreader bar.

4. The method of claim 3, further comprising directing the additive out of the spreader bar and onto the first folded film.

5. The method of claim 1, further comprising applying an additive to one or more of an inner surface of the first folded film or an outer surface of the second folded film.

6. The method of claim 1, wherein the first and second folded films are c-folded films.

7. The method of claim 1, further comprising

Advancing a third folded film in a second direction of travel;

inserting a third folded film between the first half and the second half of the first folded film; and

the third folded film is redirected from the second direction of travel to the first direction of travel while the third folded film is between the first half and the second half of the first folded film.

8. The method of claim 7, wherein the third folded film is a monolayer film.

9. The method of claim 1, wherein the second direction of travel is perpendicular to the first direction of travel.

10. The method of claim 1, further comprising advancing the second folded film in the first direction of travel over the first folded film before advancing the second folded film in the second direction of travel.