US20220194666A1

US20220194666A1 - Magnetically resealable bag and methods of making the same

Info

Publication number: US20220194666A1
Application number: US17/555,380
Authority: US
Inventors: Randall A. Boudouris; Kevin Joseph Harrison; Craig Molter; Thomas Stiers
Original assignee: MagnetNotes Ltd
Current assignee: MagnetNotes Ltd
Priority date: 2020-12-20
Filing date: 2021-12-18
Publication date: 2022-06-23

Abstract

A magnetically resealable bag including a polymer substrate. The polymer substrate including a front panel, a back panel, a closed bottom and an opening. The inside of the opening including a first side strip and a second side strip. The first side strip and second side strip include a layer of a magnetizable composition, and at least one layer of a polymer material arranged to provide a covering over the layer of the magnetizable composition. A top portion of the first side strip is coupled to the inside at the front panel of the bag and a top portion of the second side strip is coupled to the inside of the back panel of the bag, and a bottom portion of the first and second side strip is free of the inside of the opening. The first side strip and second side strip are aligned and permanently magnetized.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/128,113, filed Dec. 20, 2020, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present disclosure relates to a magnetically resealable bag and to methods of making the same, for example, a storage bag having a magnetic closure.
An affordable magnetic re-closure feature has long been desired in the packaging industry. However, this has not yet been practical because of the difficulty and cost of applying traditional magnets to a package.
Additionally, previous magnetically resealable storage bags have been found to lack enough magnetic strength to maintain a sufficient closure, and to ultimately leak ingredients from the magnetically resealable closure.

SUMMARY OF THE INVENTION

In one aspect, the disclosure relates to a magnetically resealable bag, the magnetically resealable bag comprising a polymeric substrate, the polymeric substrate comprising a front panel, a back panel, a closed bottom and an opening, and an inside and an outside, the inside of the opening comprising a first side strip and a second side strip, the first side strip and the second side strip comprising at least one first layer of polymer material and a layer of a magnetizable composition, the magnetizable composition comprising a thermoplastic polymer and magnetizable particles, the at least one layer of polymer material is arranged so as to provide a covering over the layer of the magnetizable composition, a top portion of the first side strip is coupled to the inside of the opening at the front panel of the bag, and a bottom portion of the first side strip is free of the inside of the opening at the front panel of the bag, a top portion of the second side strip is coupled to the inside of the opening at the back panel of the bag, and a bottom portion of the second side strip is free of the inside of opening at the back panel of the bag, and wherein the magnetizable composition of the first side strip and the second side strip are aligned and permanently magnetized so as to form a reopenable and resealable closure.
In another aspect, the present disclosure relates to a magnetically resealable bag, the magnetically resealable bag comprising a polymeric substrate, the polymeric substrate comprising a first side panel, a second side panel, a closed bottom and an opening, and an inside and an outside, the inside of the opening comprising a first side strip and a second side strip, the first side strip and second side strip comprising at least one first layer of polymer material and a layer of a magnetizable composition, the magnetizable composition comprising a thermoplastic polymer and magnetizable particles, a top portion of the first side strip and a top portion of the second side strip comprising the at least one first layer of polymer material and a bottom portion of the first side strip and the second side strip comprising the at least one layer of polymer material and the layer of the magnetizable composition wherein the at least one first layer of polymer material forms a covering over the layer of the magnetizable composition, the top portion of the first side strip is coupled to the inside of the opening at the front panel of the bag, and the bottom portion of the first side strip is free of the inside of the first side panel, and the top portion of the second side strip is coupled to the inside of the opening at the back panel, and the bottom portion of the second side strip is free of the inside of the second side panel, and wherein the first side strip and second side strip are aligned and magnetized so as to form a magnetically reopenable and resealable closure.
Alternatively or additionally to any of the embodiments above the first side strip comprises the magnetizable composition having a plurality of poles having a first leading edge comprising a first pole and the second side strip comprises a plurality of poles having a second leading edge comprising a second pole that is opposite to the first pole.
The magnetically resealable bag of claim 1 wherein the first side strip and the second side strip comprise the at least one first layer of polymer material and a second layer of polymer material.
Alternatively or additionally to any of the embodiments above the at least one first layer of polymer material is different than the second layer of polymer material.
Alternatively or additionally to any of the embodiments above the second layer of polymer material is formed of a more compliant polymer material than the at least one first layer.
Alternatively or additionally to any of the embodiments above the at least one first layer of polymer material comprises polyethylene terephthalate.
Alternatively or additionally to any of the embodiments above the second layer comprises polyethylene.
Alternatively or additionally to any of the embodiments above the top portion of the first side strip and the second side strip are coupled to the inside of the opening of the bag at the second layer.
Alternatively or additionally to any of the embodiments above, the magnetic composition comprises about 70% to about 95% magnetizable particles and about 5% to about 30% by weight polymer material.
Alternatively or additionally to any of the embodiments above, the magnetic composition comprises about 5% to about 30% of at least one polyethylene vinyl acetate.
Alternatively or additionally to any of the embodiments above, the magnetically resealable bag further comprises a removable top portion above the opening of the magnetically resealable bag and the removable top portion is laser scored above the opening to facilitate removal of the top portion of the magnetically resealable bag.
Alternatively or additionally to any of the embodiments above, the closed bottom of the bag is arranged to form a stand-up pouch.
Alternatively or additionally to any of the embodiments above, the polymeric substrate comprises a metalized foil laminated polymer.
Alternatively or additionally to any of the embodiments above, the at least one first layer of polymer material has a thickness of about 1.0 to about 2.0 mils.
Alternatively or additionally to any of the embodiments above, the at least one second layer of polymer material has a thickness of about 0.25 to about 1.0 mils.
Alternatively or additionally to any of the embodiments above, the magnetic layer has a thickness of about 8 to about 30 mils.
Alternatively or additionally to any of the embodiments above, the top portion of the first side strip is coupled to inside of the opening at the front panel of the magnetically resealable bag and the top portion of the second side strip is coupled to the inside of the opening at the bag panel of the bag by a heat seal.
In another aspect, the present disclosure relates to a method of making a magnetically resealable bag, the method comprising heating a magnetizable composition to a temperature at which the magnetizable composition is in flowable form, the magnetizable composition comprising at least one thermoplastic polymer material and magnetizable particles, extruding the magnetizable composition at an elevated temperature to a moving transfer belt or roller with a releasable coating and marrying a heat sealable film downstream to the magnetizable composition, aligning the magnetizable composition while the magnetizable composition is in flowable form, chilling the magnetizable composition, magnetizing the magnetizable composition, forming a first side strip and a second side strip of the magnetizable composition and heat sealing film, and coupling the first side strip and the second side strip to an inside surface of a magnetically resealable bag.
These and other aspects, embodiments and advantages of the present disclosure will become immediately apparent to those of ordinary skill in the art upon review of the Detailed Description and Claims to follow.
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example bag in an open state;

FIG. 2 is a perspective view of an alternative embodiment of an example bag in an open state;

FIG. 3 is a side schematic view of an example magnetic strip;

FIG. 4 is a side schematic view of an example polymer strip used as a covering for the magnet;

FIG. 5 is a side view of an example bag in an open state;

FIG. 6 is a side view of an example bag similar to that shown in FIG. 5 in a closed state;

FIG. 7 is a side view of an example bag similar to that shown in FIGS. 5 and 6 in an upside down and closed state; and

FIG. 8 is a block flow diagram illustrating an exemplary method of making a magnetically resealable bag.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include one or more particular features, structures, and/or characteristics. However, such recitations do not necessarily mean that all embodiments include the particular features, structures, and/or characteristics. Additionally, when particular features, structures, and/or characteristics are described in connection with one embodiment, it should be understood that such features, structures, and/or characteristics may also be used connection with other embodiments whether or not explicitly described unless clearly stated to the contrary.
The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.
This disclosure relates in general to magnetic re-closures for packages including flexible packaging such as polymeric bags.
Turning now to the figures, FIG. 1 is a perspective view illustrating an example magnetically resealable bag 10. In this embodiment, the magnetically resealable bag 10, formed in accordance with the present disclosure, is shown in an open state. The magnetically resealable bag 10 includes two sides 12 a and 12 b, a top portion 14, a bottom portion 16, and an opening 20. Opening 20 includes a front panel 21 a having a first side strip 24 a and a back panel 21 b having a second side strip 24 b. The first side strip 24 a and second side strip 24 b each include a layer of magnetic composition and at least one layer of a polymer material. The magnetizable composition includes at least one thermoplastic material or thermoset polymer material and magnetizable particles. The polymer materials and magnetizable particles are described in more detail below. Alternatively, the magnetizable material may include a thermoset material and magnetizable particles.
The first side strip 24 a and second side strip 24 b may be configured such that each include at least one north pole and one south pole to 30 poles for each of the first side strip 24 a and second side strip 24 b. In some instances, the first and second side strips 24 a, 24 b include multipole magnets, each having from 1 to 22 poles per strip or about 4 to 22 poles per strip. For example, an arrangement where first side strip 24 a includes a single magnet having a north pole the second side strip 24 b includes a single magnet having a south pole, for example, those made from neodymium may be formed this way, or an arrangement wherein the first side strip 24 a constitutes a magnet and second side strip 24 b constitutes a magnetic receptive material. The scope of the disclosure is not limited by these arrangements provided that the first side strip 24 a and second side strip 24 b are magnetically attracted to one another.
In some embodiments, the first magnetic strip 24 a may include a leading edge provided with a north pole magnetic orientation, and the second side strip 24 b may include a magnet having a leading edge provided with a south pole magnetic orientation. As a result, when the magnetically resealable bag 10 is closed (not shown), the magnetic orientation of first side strip 24 a and second side strip 24 b are in the proper position so as to magnetically retain the cooperating portions of the magnetically resealable bag 10 adjacent to one another during use. These arrangements are intended as illustrative only, and not as a limitation on the scope of the disclosure. Other arrangements and magnetic orientations not specifically described herein are also contemplated.
The first side strip 24 a and second side strip 24 b thus provide the magnetically resealable bag 10 with a magnetically reopenable and resealable closure 20. These features will be explained in detail below with respect to FIGS. 3 and 4. While bag 10 is depicted as being generally rectangular in shape, with two generally opposing, symmetrical side panels 12 a/12 b, other shapes and configurations are contemplated including configurations that include additional/different side panels, additional/different end regions, different shapes (e.g., polygonal, rounded, oval, irregular, etc.), and the like.
In the embodiment shown in FIG. 1, the magnetically resealable bag 10 is shown having a laser score at 22 a and 22 b to facilitate easy opening of the magnetically resealable bag 10. The magnetically resealable bag could also be provided with a tab, cut, or tear notch (shown in FIG. 2) at the laser score lines 22 a, 22 b to even further facilitate easy opening of the magnetically resealable bag 10.
The top portion 25 of the magnetically resealable bag 10 above the laser score lines 22 a, 22 b may be removed by the consumer.
The magnetically resealable bag 10 may further include a hanger hole 18 at the top portion 25 for hanging the bag on a rack in a store.
FIG. 2 is a perspective view illustrating an alternative example of a magnetically resealable bag 110. In this embodiment, the magnetically resealable bag 110, formed in accordance with the present disclosure, is shown in an open state. The magnetically resealable bag 110 includes two sides 112 a and 112 b, a top portion 114, a bottom portion 116, and an opening 120. The side portions 112 a and 112 b may be heat sealed as shown at 113 a and 113 b respectively. Opening 120 includes a front panel 121 a having a first side strip 124 a and a back panel 121 b having a second side strip 124 b. The first side strip 124 a and second side strip 124 b each include a layer of magnetic composition and at least one layer of a polymer material. The magnetizable composition includes at least one thermoplastic material or thermoset polymer material and magnetizable particles. The polymer materials and magnetizable particles are described in more detail below. Alternatively, the magnetizable material may include a thermoset material and magnetizable particles.
The first side strip 124 a and second side strip 124 b may be configured such that each include at least one north pole and one south pole to 30 poles for each of the first side strip 124 a and second side strip 124 b. In some instances, the first and second side strips 124 a, 124 b include multipole magnets, each having from 1 to 22 poles per strip or about 4 to 22 poles per strip. For example, an arrangement where first side strip 124 a includes a single magnet having a north pole the second side strip 124 b includes a single magnet having a south pole, for example, those made from neodymium may be formed this way, or an arrangement wherein the first side strip 124 a constitutes a magnet and second side strip 124 b constitutes a magnetic receptive material. The scope of the disclosure is not limited by these arrangements provided that the first side strip 124 a and second side strip 124 b are magnetically attracted to one another.
In some embodiments, the first magnetic strip 124 a may include a leading edge provided with a north pole magnetic orientation, and the second side strip 124 b may include a magnet having a leading edge provided with a south pole magnetic orientation. As a result, when the magnetically resealable bag 110 is closed (not shown), the magnetic orientation of first side strip 124 a and second side strip 124 b are in the proper position so as to magnetically retain the cooperating portions of the magnetically resealable bag 110 adjacent to one another during use. These arrangements are intended as illustrative only, and not as a limitation on the scope of the disclosure. Other arrangements and magnetic orientations not specifically described herein are also contemplated.
In this embodiment, each of the first magnetic side strip 124 a and the second magnetic side strip 124 b each include a top portion 140 a and 140 b respectively, and a bottom portion 141 a and 141 b respectively. The bottom portions 141 a and 141 b each include at least one polymer layer and one magnetic layer, while the top portions 140 a and 140 b include at least one polymer layer only. The bottom portions 141 a and 141 b are not coupled to the bag 110, but hang freely therefrom, while the top portions 140 a and 140 b are coupled to the bag 110. The structure of each magnetic side strip 124 a and 124 b will be described in more detail with respect to FIGS. 3 and 4 below.
The magnetically resealable bag 110 may further include a laser score at 122 a and 122 b to facilitate easy opening of the magnetically resealable bag 110. The magnetically resealable bag could also be provided with a tab, cut, or tear notch 123 at the laser score lines 122 a, 122 b to even further facilitate easy opening of the magnetically resealable bag 110.
The top portion 125 of the magnetically resealable bag 110 above the laser score lines 122 a, 122 b may be removed by the consumer.
The magnetically resealable bag 110 may further include a hanger hole 118 at the top portion 125 for hanging the bag on a rack in a store.
In this embodiment bag 110 is shown having a stand-up pouch 142, which is also referred to in the industry as a bottom gusset pouch or Doyen gusset pouch.
FIG. 3 is a partial side view illustrating a coextruded polymeric layer 140 including a first polymer layer 143 and a second polymer layer 145. The first polymer layer 143 is suitably formed from a more compliant polymer material than the second polymer layer 145. This particular arrangement is intended for illustrative purposes only, and not as a limitation on the scope of the present invention.
In some embodiments the first polymer layer 143 is formed from a polyolefin material, for example polyethylene, while the second polymer layer is formed from a copolymer of an ester and an olefin, for example, polyethylene terephthalate. This structure is intended for illustrative purposes only, and not as a limitation on the scope of the present invention.
It that only one layer of a polymer material 143 may be employed to wrap about the magnetic layer, or may include more than two layers of polymer materials.
The polymer layer 143 or layers is wrapped about the magnetic layer 144 and thus configured to form a barrier to and thus prevent the contents, such as food items, contained within the bag from coming into contact with the magnetic layer 144.
The coextruded strip 141 may then be wrapped around a magnetic layer 144 to form a side strip 124 as shown in FIG. 4. The first layer 143 is shown in contact with and coupled to the magnetic layer 144 while the second layer 145 is an outer layer to the magnetic layer 144 and is not in contact therewith. The side strip 124 may be used to form a first side strip 124 a and a second side strip 124 b which will be discussed in more detail with respect to FIGS. 5-7 below.
FIG. 5 is a side view of a magnetically resealable bag 110 in an open state. Bag 110 is shown from the perspective of the first side portion 112 a, and includes a top portion 114, and a bottom portion 116. The opening 120 includes a front panel 121 a having a first side strip 124 a and a back panel 121 b having a second side strip 124 b. The first side strip 124 a and second side strip 124 b each include a top portion 140 a and 140 b respectively, each of which include at least one layer of polymer material, and a bottom portion 141 a and 141 b, each of which include a layer of magnetic composition and at least one layer of a polymer material. The magnetizable composition includes at least one thermoplastic material or thermoset polymer material and magnetizable particles. The polymer materials and magnetizable particles are described in more detail below. Alternatively, the magnetizable material may include a thermoset material and magnetizable particles.
The top portions 140 a and 140 b are coupled to the inside surface of the bag. The bottom portions 141 a and 141 b are not coupled to and hang freely from the inside surface of the bag, and form pouches 146 a and 146 b between the first side strip 124 a and second side strip 124 b and the inside surface of the bag. The pouches 146 a, 146 b are configured to trap material 128, which will be discussed in more detail with respect to FIG. 7.
In the embodiment shown in FIG. 5, the top portion 140 a of the first side strip 124 a and the top portion 140 b of the second side strip 124 b each include a first layer of polymer material 143 and a second layer of polymer material 145. The bottom portion 141 a of the first side strip 124 a and the bottom portion 141 b of the second side strip 124 a each include a first layer of polymer material 143 and a second layer of polymer material which is further wrapped about a layer of magnetic material 144.
The first polymer layer 143 is coupled to the inside surface of the of the opening 120 of the bag 110 as shown at the top portion 125 a and 125 b of the front panel 121 a bag 110 and back panel 121 b of the bag. Suitably, the first polymer layer 143 is more compliant that the second polymer layer 145 so as to allow heat sealing of the first polymer layer 143 to the inside surface of the top portions 125 a and 125 b of the bag 110. The top portions 125 a and 125 b of the bag are configured to allow removal by a consumer. This can be facilitated by the addition of laser scoring and/or cuts or tabs at the sides of each of the top portions 125 a and 125 b. Suitable materials for the first polymer layer 143 and the second polymer layer 145 used to form the first side strip 24 a, 124 a and second side strip 24 b, 124 b, according to any of the embodiments above, will be discussed in more detail below.
FIG. 6 illustrates a bag similar to that shown in FIG. 5 in a closed state. The first polymer layer 143 of the top portions 140 a and 140 b of the first side strip 124 a and the second side strip 124 b are coupled to the inside surface of the bag 110, and the second polymer layer 145 is coupled to itself, for example, by heat sealing.
The bottom portions 141 a and 141 b of the first side strip 124 a and the second side strip 124 b are magnetically sealed via the magnetic layer 144 of each side strip 124 a and 124 b.
The top portions 125 a and 125 b can be removed by the consumer as discussed above, leaving a magnetically sealed, and reopenable and reclosable bag.
FIG. 7 illustrates a bag 110 similar to that shown in FIGS. 5 and 6 in an upside down and closed state. As can be seen in this figure, the pouches 146 a and 146 b formed between the bottom portions 141 a and 141 b of the first side strip 124 a and the second side strip 124 b are configured so as to trap material therein. This has been found to both prevent leakage at the magnetic seal when the bag is closed, as well as to strengthen the magnetic seal.
The bag itself according to the disclosure (and/or other bag, container, etc. disclosed herein) may be formed from any suitable polymer material including, for example, durable, recyclable and biodegradable polymer materials. Examples of durable or recyclable polymer materials include, but are not limited to, polyolefins and copolymers or terpolymers thereof, for example, polypropylene and polyethylene including HDPE, MDPE, LDPE and LLDPE, polyesters and copolymers thereof, for example, polyethylene terephthalate (PET), and so forth, and mixtures thereof. An example of a suitable bioplastic or biodegradable material is polylactic acid. Selection of the bag material is not limiting to the scope of the present disclosure.
In some embodiments, the bag may be formed from HDPE or a polyester.
Layers of polymer materials and/or other materials may also be employed. For example, a polyolefin material may be employed as an inner layer, and a polyester material may be employed as an outer layer. This is intended for illustrative purposes only, and not as a limitation on the scope of the present application.
Also, for example, the magnetically resealable bags may be laminated. For example, some bags are formed from a metallized or foil laminated polymer material, for example, an aluminum laminated polymer material.
The magnetically resealable bags may be formed by blown film extrusion of a roll of sheet material as is known in the art. This will be explained in more detail below as well as application of the first side strip and second side strip to the inside of the opening of the magnetically resealable bags. Alternatively, the resealable bags may be formed from paper or paper products or, laminated versions thereof.
The first polymer layer 143 and second polymer layer 145 may be made from any suitable polymer material including, but not limited to, polyolefins including polyethylene and polybutylene, polyesters, polyethers, polyamides, as well as copolymers and terpolymers, and mixtures thereof. As discussed above, suitably, the first polymer layer 143 is formed of a compliant polymer material to facilitate heat sealing of the first polymer layer 143 to the inner surface of the bag. The second polymer layer 145, if included, may be formed from a less compliant polymer material than the first polymer layer 143. Compliance of a polymer material is a term that is well understood in the art.
In some embodiments both a first polymer layer 143 and a second polymer layer 145 are included in the first side strip 24 a, 124 a and the second side strip 24 b, 124 b and the first polymer layer 143 is polyethylene and the second polymer layer 145 is polyethylene terephthalate.
In some embodiments, the thickness of the first polymer layer 143 ranges from about 1.0 mils to about 2.0 mils, and suitably is about 1.5 mils.
In some embodiments, the thickness of the second polymer layer 145 ranges from about 0.25 mils to about 2.0 mils, and suitably is about 0.5 mils.
A heat activated adhesive, pressure sensitive adhesive or other, may be supplied between the first polymer layer 143 and the second polymer layer 145. Optionally a heat activated adhesive, a pressure sensitive adhesive or other, may be applied to the first polymer layer 143 to further strengthen the bond between the first polymer layer 143 and the bag 10, 110.
In some embodiments, a heat activated adhesive is employed that is not tacky or soft to the touch. Heat activated adhesives may be thermoplastic or thermoset. Such polymer materials used in these adhesives include polyolefins and copolymers and terpolymers thereof, and block copolymer based adhesives.
One of ordinary skill in the art is well versed in the selection of such adhesive material. This is not limiting to the scope of the present disclosure.
Optionally, the first polymer layer 143 may be substituted with a paper substrate, with a heat activated adhesive on both sides of the paper substrate to allow heat sealing of the paper substrate to the magnetic layer 144. In this instance, biodegradable polymer may be employed to form the magnetic layer. Certified biodegradable polymer materials are described in more detail below.
The magnetizable composition forming the magnetic layer 144 of the first side strip 24 a, 124 a and second side strips 24 b, 124 b suitably includes about 70 wt-% or more of the magnetizable particles as to have a sufficient attractive force for practical uses. However, it is usually impractical to employ more than 95 wt-% of the magnetizable particles because of production concerns, and also because of the difficulty of retaining more than this in the binder material. Furthermore, including more than about 95 wt-% of the magnetic material may lead to a rougher surface.
Suitably, the magnetizable composition comprises about 70 wt-% to about 95 wt-% of the magnetizable particles and about 5 wt-% to about 30 wt-% of at least one polymer material. In some embodiments, the magnetizable composition comprises about 80 wt-% to about 90 wt-% of the magnetizable particles and about 10 wt-% to about 20 wt-% of at least one polymer material. In some embodiments, the magnetizable composition comprises about 84 wt-% to about 90 wt-% polymer material and about 16 wt-% to about 10 wt-% magnetizable particles.
The thermoplastic material, often referred to in the industry as a thermoplastic binder, suitable for use in the process of the present disclosure may include any polymeric material that is readily processable with the magnetic material on, for instance, the thermoplastic or hot melt processing equipment as described in detail below. Such thermoplastic materials include both thermoplastic elastomers and non-elastomers or any mixture thereof.
The thermoplastic composition may be selected based on, for one, the type of printable substrate which is being used, and the adhesion obtained between the thermoplastic composition and the printable substrate.
Examples of thermoplastic elastomers suitable for use herein include, but are not limited to, natural and synthetic rubbers and rubbery block copolymers, such as butyl rubber, neoprene, ethylene-propylene copolymers (EPM), ethylene-propylene-diene polymers (EPDM), polyisobutylene, polybutadiene, polyisoprene, styrene-butadiene (SBR), styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-isoprene-styrene (SIS), styrene-isoprene (SI), styrene-ethylene/propylene (SEP), polyester elastomers, polyurethane elastomers, to mention only a few, and so forth and mixtures thereof. Where appropriate, included within the scope of this disclosure are any copolymers of the above described materials.
Examples of suitable commercially available thermoplastic elastomers such as SBS, SEBS, or SIS copolymers include KRATON® G (SEBS or SEP) and KRATON® D (SIS or SBS) block copolymers available from Kraton Polymers; VECTOR® (SIS or SBS) block copolymers available from Dexco Chemical Co.; and FINAPRENE® (SIS or SBS) block copolymers available from Atofina.
Some examples of non-elastomeric polymers include, but are not limited to, polyolefins including polyethylene, polypropylene, polybutylene and copolymers and terpolymers thereof such as ethylene vinyl acetate copolymers (EVA), ethylene n-butyl acrylates (EnBA), ethylene methyl (meth) acrylates including ethylene methyl acrylates (EMA), ethylene ethyl (meth) acrylates including ethylene ethyl acrylates (EEA), interpolymers of ethylene with at least one C₃to C₂₀alphaolefin, polyamides, polyesters, polyurethanes, to mention only a few, and so forth, and mixtures thereof. Where appropriate, copolymers of the above described materials also find utility herein.
Examples of polymers useful herein may be found in U.S. Pat. No. 6,262,174 incorporated by reference herein in its entirety. Polymeric compositions exhibiting high hot tack have been found to be particularly suitable for use herein. Hot tack is a term of art known to those of ordinary skill.
Examples of commercially available non-elastomeric polymers include EnBA copolymers available from such companies as Atofina under the tradename of Lotryl® available from Arkema in the King of Prussia, Pa., from ExxonMobil Chemical in Houston, Tex. under the tradename of Escorene™, from DuPont de Nemours & Co. in Wilmington, Del. under the tradename of Elvaloy®; EMA copolymers available from ExxonMobil Chemical under the tradename of Optema™; EVA copolymers are available from DuPont′ under the tradename of Elvax® and from Lyondell Blassell in Houston, Tex. under the tradename of Ultrathene® to name only a few.
Polyolefins or polyalphaolefins can be employed herein, or copolymers or terpolymers thereof. Examples of useful polyolefins include, but are not limited to, amorphous (i.e. atactic) polyalphaolefins (APAO) including amorphous propylene homopolymers, propylene/ethylene copolymers, propylene/butylene copolymers and propylene/ethylene/butylene terpolymers; isotactic polyalphaolefins; and linear or substantially linear interpolymers of ethylene and at least one alpha-olefin including, for instance, ethylene and 1-octene, ethylene and 1-butene, ethylene and 1-hexene, ethylene and 1-pentene, ethylene and 1-heptene, and ethylene and 4-methyl-1-pentene and so forth. In some embodiments, a small amount of another polymer may be used in combination with the polyalphaolefin such as maleic anhydride grafted polymers which have been used to improve wetting and adhesion. Other chemical grafting can be used, but maleic anhydride is by far the most common. Usually only a few percent in grafting (1-5%) are used and most tend to be ethylene or propylene copolymers.
Examples of suitable certified biodegradable polymer materials include, but are not limited to polylactic acids or polylactides, polyhydroxyvalerate/hydroxybutyrate, and mixtures thereof.
Thermoset polymer materials may also be employed which are cured in a variety of manners such as moisture cure, radiation cure, two-part chemical reactions, heat, and so forth to form substantially insoluble or infusible materials. Such materials are well known in the art.
Thermoset polymers crosslink and/or polymerize by energy or by chemical means and by a wide variety of mechanisms including, but not limited to, moisture cure, thermal and radiation cure, condensation, free radical systems, oxidative cures, etc. as well as combinations thereof.
Some examples of suitable thermoset materials include, but are not limited to, polyurethanes, polyureas, polyurethane/polyurea hybrids, epoxies, acrylics, polyesters, (meth)acrylates, cyanoacrylates, silicones (polysiloxanes), polyolefins and copolymers thereof such as ethylene vinyl acetate copolymers, rubbers including rubbery block copolymers, etc.
Each of class of thermoset material may come in a variety of different systems, including, for example, one and two part systems, and radiation curing systems such as radiation (e.g. UV) curing systems, moisture cure, etc.
In some embodiments, the magnetic composition includes a multicomponent epoxy or urethane thermoset composition. The thermoset polymer compositions may also be employed in combination with magnetic receptive particle materials.
In some embodiments, the thermoset polymer composition is cured using electron beam (e-beam) radiation. Crosslinking of polymer based products via e-beam radiation improves mechanical, thermal and chemical properties. Specifically, thermal resistance to temperature degradation and aging and low temperature impact resistance are improved.
Tensile strength, modulus, abrasion resistance, resistance to creep, stress crack resistance, resistance to high pressure, and so forth are increased.
Polymers which are commonly crosslinked using the electron beam irradiation process include polyvinyl chloride (PVC), thermoplastic polyurethanes and elastomers (TPUs), polybutylene terephthalate (PBT), polyamides/nylon (PA66, PA6, PA11, PA12), polyvinylidene fluoride (PVDF), (meth)acrylates, polymethylpentene (PMP), polyethylenes (LLDPE, LDPE, MDPE, HDPE, UHMWPE), and ethylene copolymers such as ethylene-vinyl acetate (EVA) and ethylene tetrafluoroethylene (ETFE). Some of the polymers utilize additives to make the polymer more readily irradiation crosslinkable.
The above thermoset materials may include monomers, dimers, oligomers and polymers, as well as combinations thereof as is known to those of ordinary skill in the art.
Other suitable additives can be employed in the magnetizable composition as well such as antioxidants and processing aids. One of ordinary skill in the art is knowledgeable as to hot melt additives.
The magnetizable composition may include any suitable magnetizable particles including, but not limited to, various types of ferrites, strontium, neodymium, samarium and cobalt.
In some embodiments, neodymium, strontium ferrite or samarium cobalt or some combination thereof is employed.
Magnetic materials which are particularly suitable for use herein include the ferrites having the general formula (M²⁺O₆Fe₂O₃) MFe₁₂O₁₉where M represents Ba or Sr.
Other examples of magnetic materials suitable for use herein include a rare earth-cobalt magnet of RCO₅where R is one or more of the rare earth elements such as Sm or Pr, yttrium (Y), lanthanum (La), cerium (Ce), and so forth.
Other specific examples of magnetic materials include, for instance, manganese-bismuth, manganese-aluminum, and so forth.
The viscosity of the magnetizable composition may range from about 5000 cPs to about 500,000 cPs.
The above lists are intended for illustrative purposes only, and not as a limitation on the present disclosure. It is within purview of those of ordinary skill in the art to select other polymers without departing from the scope of this disclosure.
The polymer material and the magnetizable particles can be added to and melted in mixer or an extruder, or can be supplied in the form of pre-made pellets.
The magnetic strength of the finished product is a function of the amount of magnetic material or powder in the mix, the surface area, thickness, and method of magnetization (e.g. whether it is aligned or not).
Coating thicknesses of the magnetic layer may range from about 8 mils to about 30 mils.
The method of the present disclosure is not limited to any particular magnetic material, and the scope of the disclosure is therefore not intended to be limited as such. While the above described materials find particular utility in the process of the present disclosure, other materials which are readily permanently magnetized may also find utility herein.
The magnetizable composition is heated to a temperature at which it is molten or flowable using any suitable hot melt or thermoplastic equipment. The mixture is then supplied to a melt pump or small extruder via any suitable means such as an auger.
In its simplest form, the method of forming the magnetically resealable bag includes heating a magnetizable composition to a temperature at which the magnetizable composition is in flowable form, the magnetizable composition comprising at least one thermoplastic polymer material and magnetizable particles, extruding the magnetizable composition at an elevated temperature to a moving transfer belt or roller with a releasable coating and marrying a heat sealable film downstream to the magnetizable composition, aligning the magnetizable composition while the magnetizable composition is in flowable form, chilling the magnetizable composition, magnetizing the magnetizable composition to form a first magnet and a second magnet, forming a first side strip and a second side strip of the magnetizable composition and heat sealing film, and coupling the first side strip and the second side strip to an inside surface of a magnetically resealable bag.
FIG. 8 is a block flow diagram of an exemplary method of forming a bag according to the present disclosure. As shown in FIG. 8, the magnetizable composition is mixed and formed into pellets in a separate process. The pellets are then melted and extruded at a temperature of about 375° F. until molten. The molten magnetizable composition is then passed through a slot die and formed into a hot strip onto the side of a transfer belt or carrier material, such as a Teflon or Teflon coated transfer belt to form the magnetic layer 144.
The first layer 143 of the polymer strip 140 is applied downstream to both sides of the magnetic layer 144 to encapsulate the magnetic layer 144 therein. This assembly will form both the first side strip 24 a, 124 a and the second side strip 24 b, 124 b.
A second polymer layer 145 may be already coupled to or simultaneously married to the first polymer layer 143.
The magnetic layer 144 may be applied to the first polymer layer 143 at a temperature of about □□□°□F to 400° F.
The width of each layer that forms the first strip 24 a, 124 a and the second side strip 24 b, 124 b may range from ⅛ inch to 2 inches.
This assembly is then conveyed to and passed through a chill roller/magnetizer to permanently magnetize the magnetic layer 144.
A rare earth magnet can be used to magnetize the material used to form the magnetic layer 144. The magnetizer can be between two poles per inch and twenty-six poles per inch. The magnetizer may be built around a drum and internally cooled. The coated material may be maintained at peak magnetizing temperatures using a heat tunnel or other suitable means of supplying heat. The magnetizer may, for example, be formed from neodymium or samarium cobalt. In some embodiments, the operating temperature of the magnetizer should not exceed 225° F.
In some embodiments a chill roll that is wrapped in magnets such as neodymium magnets is employed. Strontium ferrite and samarium cobalt may also be employed alone or in combination with neodymium magnets. Other examples of suitable magnets include, but are not limited to, neodymium ferrite, barium ferrite, and lead ferrite. The molten magnetizable composition may be aligned, chilled and magnetized in a single step as it winds around the chill roll.
The assembly is then transfer wound onto spools. Two spools, one which forms the first side strip 24 a, 124 a and one which forms the second side strip 24 b, 124 b are then mounted onto unwind stands on the bag forming line.
The first side strip 24 a, 124 a and second side strip 24 b, 124 b are pulled into the bag making machine and heat sealed onto the inner surface of each side of a preformed bag.
The first side strip 24 a, 124 a and the second side strip 24 b, 124 b may be heat sealed to the inner surface of a magnetically resealable bag 10, 110 at a temperature ranging from about 200° F. to about 450° F. depending on how fast the bag line is running. Line speeds may range from about 50 feet/minute to about 1000 feet/minute, suitably greater than about 80 feet/minute to about 500 feet/minute.
The sides and/or bottom of the bag may then be passed to heat sealing stations to heat seal the sides and/or bottom of the bag to form for example, a stand up bag or pouch.
This method is intended for illustrative purposes only. Other methods of bag forming may be employed herein. For example, in some methods, the first side strip 24 a, 124 a and second side strip 24 b, 124 b including the magnetic layer 144 and the first polymer layer 143 may optionally be extruded and applied directly to the surface of a bag substrate or a preformed bag, rather than transfer coating as described in the embodiment above.
The finished product is then boxed and shipped to various food suppliers.
Those spools are then conveyed to a bag forming line, and the sides and bottom of the bag are heat sealed to make stand up bags or pouches.
The magnetically resealable bags formed according to the present disclosure may be employed for storage of any of a variety of items as well as for prepackaged food products such as chips, crackers, nuts, candies, cereal, frozen foods such as frozen fruits and vegetables and so forth. This list is intended for illustrative purposes only, and not as a limitation on the scope of the present disclosure.
The description provided herein is not to be limited in scope by the specific embodiments described which are intended as single illustrations of individual aspects of certain embodiments. The methods, compositions and devices described herein can comprise any feature described herein either alone or in combination with any other feature(s) described herein. Indeed, various modifications, in addition to those shown and described herein, will become apparent to those skilled in the art from the foregoing description and accompanying drawings using no more than routine experimentation. Such modifications and equivalents are intended to fall within the scope of the appended claims.
U.S. Pat. No. 7,501,921 is incorporated herein by reference herein in its entirety. U.S. Pat. No. 7,128,798 to Boudouris et al., U.S. Pat. No. 7,338,573 to Boudouris et al., U.S. Pat. No. 7,501,921 to Boudouris et al., US Patent Application No. 2006/0165880 to Boudouris et al., and US Patent Application No. 2017/0275056 A1 are all incorporated herein by reference.
All published documents, including all US patent documents and US patent publications, mentioned anywhere in this application are hereby expressly incorporated herein by reference in their entirety. Any copending patent applications, mentioned anywhere in this application are also hereby expressly incorporated herein by reference in their entirety. Citation or discussion of a reference herein shall not be construed as an admission that such is prior art.
While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

Claims

What is claimed is:

1. A magnetically resealable bag, the magnetically resealable bag comprising:

a polymeric substrate, the polymeric substrate comprising a front panel, a back panel, a closed bottom and an opening, and an inside and an outside;

the inside of the opening comprising a first side strip and a second side strip;

the first side strip and the second side strip comprising at least one first layer of polymer material and a layer of a magnetizable composition, the magnetizable composition comprising a thermoplastic polymer and magnetizable particles, the at least one first layer of polymer material is arranged so as to provide a covering over the layer of the magnetizable composition;

a top portion of the first side strip is coupled to the inside of the opening at the front panel of the bag, and a bottom portion of the first side strip is free of the inside of the opening at the front panel of the bag;

a top portion of the second side strip is coupled to the inside of the opening at the back panel of the bag, and a bottom portion of the second side strip is free of the inside of opening at the back panel of the bag; and

wherein the magnetizable composition of the first side strip and the second side strip are aligned and permanently magnetized so as to form a reopenable and resealable closure.

2. The magnetically resealable bag of claim 1, wherein the first side strip comprises the magnetizable composition having a plurality of poles having a first leading edge comprising a first pole and the second side strip comprises a plurality of poles having a second leading edge comprising a second pole that is opposite to the first pole.

3. The magnetically resealable bag of claim 1 wherein the first side strip and the second side strip comprise the at least one first layer of polymer material and a second layer of polymer material.

4. The magnetically resealable bag of claim 3, wherein the at least one first layer of polymer material is different than the second layer of polymer material.

5. The magnetically resealable bag of claim 4, wherein the first layer of polymer material is formed of a more compliant polymer material than the at least one first layer.

6. The magnetically resealable bag of claim 1, wherein the at least one first layer of polymer material comprises polyethylene.

7. The magnetically resealable bag of claim 3, wherein the second layer comprises polyethylene terephthalate.

8. The magnetically resealable bag of claim 3, wherein the top portion of the first side strip and the second side strip are coupled to the inside of the opening of the bag at the second layer.

9. The magnetically resealable bag of claim 8, wherein the top portion of the first side strip and the top portion of the second side strip are coupled to the inside of the opening of the bag with the at least one first layer of polymer material.

10. The magnetically resealable bag of claim 1, wherein the magnetic composition comprises about 70% to about 95% magnetizable particles and about 5% to about 30% by weight polymer material.

11. The magnetically resealable bag of claim 1, wherein the magnetically resealable bag further comprises a removable top portion above the opening of the magnetically resealable bag and the removable top portion is laser scored above the opening to facilitate removal of the top portion of the magnetically resealable bag.

12. The magnetically resealable bag of claim 1, wherein the closed bottom of the bag is arranged to form a stand-up pouch.

13. The magnetically resealable bag of claim 1, wherein the polymeric substrate comprises a metallized foil laminated polymer.

14. The magnetically resealable bag of claim 1, wherein the at least one first layer of polymer material has a thickness of about 1.0 to about 2.0 mils.

15. The magnetically resealable bag of claim 3, wherein the at least one second layer of polymer material has a thickness of about 0.25 to about 1.0 mils.

16. The magnetically resealable bag of claim 1, wherein the magnetic layer has a thickness of about 8 to about 30 mils.

17. A magnetically resealable bag, the magnetically resealable bag comprising:

a polymeric substrate, the polymeric substrate comprising a first side panel, a second side panel, a closed bottom and an opening, and an inside and an outside;

the first side strip and second side strip comprising at least one first layer of polymer material and a layer of a magnetizable composition, the magnetizable composition comprising a thermoplastic polymer and magnetizable particles;

a top portion of the first side strip and a top portion of the second side strip comprising the at least one first layer of polymer material and a bottom portion of the first side strip and the second side strip comprising the at least one layer of polymer material and the layer of the magnetizable composition wherein the at least one first layer of polymer material forms a covering over the layer of the magnetizable composition;

the top portion of the first side strip is coupled to the inside of the opening at the front panel of the bag, and the bottom portion of the first side strip is free of the inside of the first side panel; and

the top portion of the second side strip is coupled to the inside of the opening at the back panel, and the bottom portion of the second side strip is free of the inside of the second side panel; and

wherein the first side strip and second side strip are aligned and magnetized so as to form a magnetically reopenable and resealable closure.

18. The magnetically resealable bag of claim 17, wherein the top portion of the first side strip is coupled to inside of the opening at the front panel of the magnetically resealable bag and the top portion of the second side strip is coupled to the inside of the opening at the bag panel of the bag by a heat seal.

19. The magnetically resealable bag of claim 17, wherein the first side strip and the second side strip comprise the at least one first layer of polymer material and a second layer of polymer material.

20. A method of making a resealable package, the method comprising:

a) heating a magnetizable composition to a temperature at which the magnetizable composition is in flowable form, the magnetizable composition comprising at least one thermoplastic polymer material and magnetizable particles;

b) extruding the magnetizable composition at an elevated temperature to a moving transfer belt or roller with a releasable coating and marrying a heat sealable film downstream to the magnetizable composition;

c) aligning the magnetizable composition while the magnetizable composition is in flowable form;

d) chilling the magnetizable composition;

e) magnetizing the magnetizable composition to form a first magnet and a second magnet;

f) forming a first side strip and a second side strip of the magnetizable composition and heat sealing film; and

g) coupling the first side strip and the second side strip to an inside surface of a magnetically resealable bag.