Patent Application
20220194666
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.
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.
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,
The first side strip 24a and second side strip 24b 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 24a and second side strip 24b. In some instances, the first and second side strips 24a, 24b 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 24a includes a single magnet having a north pole the second side strip 24b 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 24a constitutes a magnet and second side strip 24b constitutes a magnetic receptive material. The scope of the disclosure is not limited by these arrangements provided that the first side strip 24a and second side strip 24b are magnetically attracted to one another.
In some embodiments, the first magnetic strip 24a may include a leading edge provided with a north pole magnetic orientation, and the second side strip 24b 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 24a and second side strip 24b 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 24a and second side strip 24b 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
In the embodiment shown in
The top portion 25 of the magnetically resealable bag 10 above the laser score lines 22a, 22b 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.
The first side strip 124a and second side strip 124b 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 124a and second side strip 124b. In some instances, the first and second side strips 124a, 124b 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 124a includes a single magnet having a north pole the second side strip 124b 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 124a constitutes a magnet and second side strip 124b constitutes a magnetic receptive material. The scope of the disclosure is not limited by these arrangements provided that the first side strip 124a and second side strip 124b are magnetically attracted to one another.
In some embodiments, the first magnetic strip 124a may include a leading edge provided with a north pole magnetic orientation, and the second side strip 124b 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 124a and second side strip 124b 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 124a and the second magnetic side strip 124b each include a top portion 140a and 140b respectively, and a bottom portion 141a and 141b respectively. The bottom portions 141a and 141b each include at least one polymer layer and one magnetic layer, while the top portions 140a and 140b include at least one polymer layer only. The bottom portions 141a and 141b are not coupled to the bag 110, but hang freely therefrom, while the top portions 140a and 140b are coupled to the bag 110. The structure of each magnetic side strip 124a and 124b will be described in more detail with respect to
The magnetically resealable bag 110 may further include a laser score at 122a and 122b 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 122a, 122b 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 122a, 122b 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.
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
The top portions 140a and 140b are coupled to the inside surface of the bag. The bottom portions 141a and 141b are not coupled to and hang freely from the inside surface of the bag, and form pouches 146a and 146b between the first side strip 124a and second side strip 124b and the inside surface of the bag. The pouches 146a, 146b are configured to trap material 128, which will be discussed in more detail with respect to
In the embodiment shown in
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 125a and 125b of the front panel 121a bag 110 and back panel 121b 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 125a and 125b of the bag 110. The top portions 125a and 125b 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 125a and 125b. Suitable materials for the first polymer layer 143 and the second polymer layer 145 used to form the first side strip 24a, 124a and second side strip 24b, 124b, according to any of the embodiments above, will be discussed in more detail below.
The bottom portions 141a and 141b of the first side strip 124a and the second side strip 124b are magnetically sealed via the magnetic layer 144 of each side strip 124a and 124b.
The top portions 125a and 125b can be removed by the consumer as discussed above, leaving a magnetically sealed, and reopenable and reclosable bag.
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 24a, 124a and the second side strip 24b, 124b 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 24a, 124a and second side strips 24b, 124b 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 C3 to C20 alphaolefin, 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) MFe12O19 where M represents Ba or Sr.
Other examples of magnetic materials suitable for use herein include a rare earth-cobalt magnet of RCO5 where 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.
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 24a, 124a and the second side strip 24b, 124b.
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 24a, 124a and the second side strip 24b, 124b 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 24a, 124a and one which forms the second side strip 24b, 124b are then mounted onto unwind stands on the bag forming line.
The first side strip 24a, 124a and second side strip 24b, 124b 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 24a, 124a and the second side strip 24b, 124b 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 24a, 124a and second side strip 24b, 124b 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.
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.
| Number | Date | Country | |
|---|---|---|---|
| 63128113 | Dec 2020 | US |
