EP3694788A1 - Emballages refermables à géométrie de joint d'étanchéité accordable - Google Patents

Emballages refermables à géométrie de joint d'étanchéité accordable

Info

Publication number
EP3694788A1
EP3694788A1 EP18793066.4A EP18793066A EP3694788A1 EP 3694788 A1 EP3694788 A1 EP 3694788A1 EP 18793066 A EP18793066 A EP 18793066A EP 3694788 A1 EP3694788 A1 EP 3694788A1
Authority
EP
European Patent Office
Prior art keywords
layer
seal
film
reclose
facial surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP18793066.4A
Other languages
German (de)
English (en)
Inventor
Vivek KALIHARI
Chuan-Yar LAI
Erica SPIEKERMANN
Cristina Serrat
Marc S. BLACK
Daniel S. WOODMAN
Chad V. Schuette
Piyush Soni
Xiaosong Wu
Daniel W. HIMMELBERGER
Vinita YADAV
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Global Technologies LLC
Rohm and Haas Co
Original Assignee
Dow Global Technologies LLC
Rohm and Haas Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dow Global Technologies LLC, Rohm and Haas Co filed Critical Dow Global Technologies LLC
Publication of EP3694788A1 publication Critical patent/EP3694788A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D33/00—Details of, or accessories for, sacks or bags
    • B65D33/16—End- or aperture-closing arrangements or devices
    • B65D33/18—End- or aperture-closing arrangements or devices using adhesive applied to integral parts, e.g. to flaps
    • B65D33/20—End- or aperture-closing arrangements or devices using adhesive applied to integral parts, e.g. to flaps using pressure-sensitive adhesive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D75/00—Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes, or webs of flexible sheet material, e.g. in folded wrappers
    • B65D75/52—Details
    • B65D75/58—Opening or contents-removing devices added or incorporated during package manufacture
    • B65D75/5855—Peelable seals

Definitions

  • This disclosure relates to packaging articles. More specifically, this disclosure relates to resealable packaging articles and resealable packaging articles including adhesives.
  • the reclosabe packages of the present disclosure are structurally designed to have reclosable seals that can be integrated into the packaging.
  • the reclosable seals involved in packages of the present disclosure are versatile and can be modified to fit a variety of packaging sizes, shapes, and types. Additionally, the reclosable seals may be modified to tune or adjust the opening force and reclose pressure of the seal.
  • the reclosable packages may also include a multilayer film and the walls of the package may include the multilayer film.
  • the package designs additionally allow for the integration of adhesive compositions with relatively low SBC content and improved odor into the reclosable seal.
  • a reclosable package comprises a front wall, a rear wall, and a closure region proximate to an outer edge of the container opposite a bottom of the container.
  • the closure region comprises a plurality of seal regions forming a continuous seal between the front wall and the rear wall across a width of the package and at least one of the seal regions is nonlinear.
  • the closure region further comprises at least one unsealed region defined between the seal regions.
  • FIG. 1A schematically depicts a front view of a closure region of a reclosable package, according to one or more embodiments of the present disclosure
  • FIG. IB schematically depicts a front view of a closure region of a reclosable package, according to one or more embodiments of the present disclosure
  • FIG. 1C schematically depicts a front view of a closure region of a reclosable package, according to one or more embodiments of the present disclosure
  • FIG. 2A schematically depicts a front perspective view of a reclosable package, according to one or more embodiments of the present disclosure
  • FIG. 2B schematically depicts a front perspective view of a reclosable package, according to one or more embodiments of the present disclosure
  • FIG. 3A schematically depicts a front perspective view of a reclosable package, according to one or more embodiments of the present disclosure
  • FIG. 3B schematically depicts a front perspective view of the reclosable package of FIG. 3A after an opening force is applied, according to one or more embodiments of the present disclosure
  • FIG. 4 schematically depicts a cross-sectional view of a reclose film that includes three layers, according to one or more embodiments of the present disclosure
  • FIG. 5 schematically depicts a cross-sectional view of another reclose film that includes 4 layers, according to one or more embodiments of the present disclosure
  • FIG. 6A schematically depicts a cross-sectional view of the reclose film of FIG. 4 adhered to a substrate, according to one or more embodiments of the present disclosure
  • FIG. 6B schematically depicts a cross-sectional view of the reclose film of FIG. 6A in which the reclose film has been initially opened to activate the reclose functionality of the reclose film, according to one or more embodiments of the present disclosure
  • FIG. 6C schematically depicts a cross-sectional view of the reclose film of FIG. 6B in which the reclose film has been reclosed following initial opening of the reclose film, according to one or more embodiments of the present disclosure
  • FIG. 6D schematically depicts a cross-sectional view of the reclose film of FIG. 6C in which the reclose film has been reopened after being reclosed, according to one or more embodiments of the present disclosure
  • FIG. 7A schematically depicts a cross-sectional view of the reclose film of FIG. 6A taken along reference line 7A-7A in FIG. 6A, according to one or more embodiments of the present disclosure
  • FIG. 7B schematically depicts a cross-sectional view of the reclose film of FIG. 7A in which the reclose film has been initially opened to activate the reclose functionality of the reclose film, according to one or more embodiments of the present disclosure.
  • Embodiments of the present disclosure are directed to reclosable packages.
  • Reclosable packages of the present disclosure comprise a front wall, a rear wall, and a bottom of the package.
  • the closure region comprises a plurality of seal regions forming a continuous seal between the front wall the rear wall across a width of the package.
  • a "seal" refers to a closure of two or more items in contact, direct or indirect, that is tight enough to prevent passage of unwanted materials through the point or surface of contact.
  • a seal may be mechanical or chemical in nature.
  • a mechanical seal might consist of two rigid surfaces that are interlocked in such a fashion as to prevent movement of the surfaces and movement between the surfaces, such as zippers, snap lids, or similar devices.
  • Examples of chemical seals include solders, welds, adhesives, or similar substances that use a temperature, pressure, or a combination thereof to introduce a chemical composition that prevents movement of two or more items.
  • the seal encompasses the items in contact, the surface or point of contact, and any other materials that might be at the surface or point of contact.
  • the tightness of a seal may vary; hermetic seals, particle-tight seals, dust-tight seals, water-tight seals, liquid-tight seals, air-tight seals, wet gas-tight seals, or dry gas-tight seals are contemplated.
  • two or more items can be said to be "sealed” together when a surface of contact, direct or indirect, between the items is part of a seal.
  • the seal may be a result of the chemical or mechanical interactions between the items at the surface.
  • two objects can be said to be sealed together.
  • contact can mean either direct contact or indirect contact.
  • Direct contact refers to contact in the absence of intervening material and indirect contact refers to contact through one or more intervening materials. Items in direct contact touch each other. Items in indirect contact do not touch each other, but do touch an intervening material or series of intervening materials, where the intervening material or at least one of the series of intervening materials touches the other. Items in contact may be rigidly or non-rigidly joined.
  • Contacting refers to placing two items in direct or indirect contact. Items in direct contact may be said to directly contact each other. Items in indirect contact may be said to indirectly contact each other. It should be understood that, in some embodiments, when two items are "in contact" with one another, they are in direct contact with one another.
  • polymer refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type.
  • the generic term polymer thus embraces the term “homopolymer” usually employed to refer to polymers prepared from only one type of monomer as well as “copolymer” which refers to polymers prepared from two or more different monomers.
  • block copolymer refers to a polymer comprising two or more chemically distinct regions or segments (referred to as "blocks"). In some embodiments, these blocks may be joined in a linear manner, that is, a polymer comprising chemically differentiated units which are joined end-to-end.
  • a "random copolymer” as used herein comprises two or more polymers where each polymer may comprise a single unit or a plurality of successive repeat units along the copolymer chain back bone. Even though some of the units along the copolymer chain backbone exist as single units, these are referred to as polymers herein.
  • Polyethylene or "ethylene-based polymer” shall mean polymers comprising greater than 50% by weight of units which have been derived from ethylene monomer. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers).
  • Common forms of polyethylene known in the art include Low Density Polyethylene (LDPE); Linear Low Density Polyethylene (LLDPE); Ultra Low Density Polyethylene (ULDPE); Very Low Density Polyethylene (VLDPE); single-site catalyzed Linear Low Density Polyethylene, including both linear and substantially linear low density resins (m- LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE).
  • ethylene/a-olefin random copolymer is a random copolymer comprising greater than 50% by weight of units derived from ethylene monomer.
  • LDPE low density polymer
  • high pressure ethylene polymer or “highly branched polyethylene” and is defined to mean that the polymer is partly or entirely homopolymerized or copolymerized in autoclave or tubular reactors at pressures above 14,500 psi (100 MPa) with the use of free-radical initiators, such as peroxides (see for example US 4,599,392, which is hereby incorporated by reference).
  • LDPE resins typically have a density in the range of 0.916 to 0.935 g/cm.
  • LLDPE includes resin made using Ziegler-Natta catalyst systems as well as resin made using single-site catalysts, including, but not limited to, bis-metallocene catalysts (sometimes referred to as "m-LLDPE") and constrained geometry catalysts, and resin made using post-metallocene, molecular catalysts.
  • LLDPE includes linear, substantially linear or heterogeneous polyethylene copolymers or homopolymers. LLDPEs contain less long chain branching than LDPEs and includes the substantially linear ethylene polymers which are further defined in U.S. Patent 5,272,236, U.S. Patent 5,278,272, U.S.
  • Patent 5,582,923 and US Patent 5,733,155 the homogeneously branched linear ethylene polymer compositions such as those in U.S. Patent No. 3,645,992; the heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698; and/or blends thereof (such as those disclosed in US 3,914,342 or US 5,854,045).
  • the LLDPE resins can be made via gas-phase, solution-phase or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art.
  • MDPE refers to polyethylenes having densities from 0.926 to 0.935 g/cc.
  • MDPE is typically made using chromium or Ziegler-Natta catalysts or using single-site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts.
  • HDPE refers to polyethylenes having densities greater than about 0.935 g/cc, which are generally prepared with Ziegler-Natta catalysts, chrome catalysts or single-site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts.
  • ULDPE refers to polyethylenes having densities of 0.880 to 0.912 g/cc, which are generally prepared with Ziegler-Natta catalysts, single-site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts, and post-metallocene, molecular catalysts.
  • polyethylene-based polymer refers to a polymer that comprises, in polymerized form, refers to polymers comprising greater than 50% by weight of units which have been derived from propylene monomer.
  • These polypropylene materials are generally known in the art.
  • styrenic block copolymer refers to a block copolymer that is produced from the polymerization of styrene monomer and at least one other comonomer.
  • Mw Molecular Weight Distribution
  • Mn Molecular Weight Distribution
  • melt index (I 2 ) is a measure of melt flow rate of a polymer as measured by ASTM D1238 at a temperature of 190°C and a 2.16 kg load.
  • a reclosable package 100 comprises a front wall 110, a rear wall 120, and a bottom 130 of the reclosable package 100.
  • the package may further comprise an outer edge 132 opposite the bottom 130.
  • the bottom 130 may be the bottom edge of the front wall 110 and the rear wall 120 sealed to each other.
  • the bottom 130 may be a wall disposed between the front wall 110 and rear wall 120.
  • the package may further comprise side edges 134 that may be longitudinally sealed.
  • the package further comprises a closure region 150 proximate to the outer edge 132.
  • the closure region 150 comprises a plurality of seal regions 160 and at least one unsealed region 170.
  • a "seal region” 160 is a region in which the front wall 110 and rear wall 120 are sealed together.
  • an "unsealed region,” as used in this disclosure is a region in which the front wall 110 and rear wall 120 are not sealed together.
  • the front wall 110 and the rear wall 120 are spaced apart throughout the entirety of the unsealed region. This gap may comprise space, air, other gases, or other fluids.
  • an unsealed region may comprise areas where the front wall and rear wall are in contact, but not sealed together.
  • the plurality of seal regions 160 may cooperate to form a continuous seal between the front wall 110 and the rear wall 120 extending across a width wi of the reclosable package 100.
  • at least one of the seal regions 160 is nonlinear.
  • “nonlinear” refers to an object that is not a straight line or not in the shape of a straight line. Additionally, as used herein in the context of multiple objects, “nonlinear” may refer to an organization of objects that are not arranged in a straight line.
  • the closure region 150 further comprises at least one unsealed region 170 defined between the seal regions 160.
  • the closure regions 150 of several example, but not intended to be limiting, reclosable packages 100 with various seal geometries are isolated and presented in FIGS. 1A-1C.
  • a plurality of seal regions 160 are disposed within the closure region 150.
  • the closure region 150 extends up to a seal region 160 furthest from the bottom 130, seal region 160a, and down to a seal region 160 closest to the bottom, seal region 160b, across a width w, defined between side edges 134.
  • the closure region 150 further comprises unsealed regions 170 defined between the seal regions 160. Still referring to FIG. 1A, the labeled unsealed region 170 is defined by the upper and lower boundaries of the closure region 150 and the seal regions 160c,160d.
  • the closure region 150 further comprises two or more seal lines 180.
  • a seal line 180 is a linear continuous seal between the front wall 110 and the rear wall 120, across the width w 2 of the closure region 150.
  • the two or more seal lines 180 comprise an upper seal line 182, the seal line 180 farthest from the bottom 130, and a lower seal line 184, the seal line 180 closest to the bottom 130.
  • the at least one nonlinear seal region 160 is disposed between the upper seal line 182 and the lower seal line 184.
  • a theoretical line can be drawn parallel to the bottom 130, through the closure region 150, not intersecting with any seal lines 180 that passes through seal regions 160 and at least one unsealed region 170.
  • the closure region 150 a reclosable package 100 comprises three seal lines 180, one of which is the upper seal line 182 and a second of which is the lower seal line 184.
  • the closure region 150 further comprises a plurality of seal regions 160 and unsealed regions 170 disposed between the upper seal line 182 and the lower seal line 184.
  • a reclosable package 100 comprises a closure region 150 proximate to the outer edge 132 as illustrated in FIG. 1A.
  • a reclosable package 100 comprises a closure region 150 that may comprise two or more seal lines 180.
  • the two or more seal lines 180 may comprise an upper seal line 182 and a lower seal line 184.
  • a plurality of seal regions 160 and a plurality of unsealed regions 170 may be disposed between the upper seal line 182 and the lower seal line 184.
  • a reclosable package 100 may further comprise a border seal 138.
  • the border seal 138 is a contiguous region in which the front wall 110 is sealed to the rear wall 120 that may extend from the seal edge 134 to a border edge 136.
  • the border seal 138 may extend past the bottom 130, surround the bottom 130 and extend along the length of a second seal edge 134.
  • the application of an opening force proximate to the closure region 150 is operable to separate at least part of the front wall 110 from the rear wall 120, breaking the continuous seal between the front wall 110 and the rear wall 120 across a width w 2 of the closure region 150.
  • FIG. 3B in one or more embodiments, after portions of the front wall 110 and rear wall 120 separate along width w 2 , as described herein, the front wall 110 and rear wall 120 remain sealed along the border seal 138.
  • the front wall 110, the rear wall 120, or combinations thereof may comprise a reclose film.
  • the closure region 150 may comprise a strip of reclose film disposed between the front wall 110 and the rear wall 120.
  • a reclose film is a multilayer film comprising at least three layers: an A layer, a B layer, and a C layer.
  • Layer A may be a sealant layer
  • Layer B may be a reclose layer and include the composition disclosed herein and subsequently described
  • Layer C may include a support material, such as a polyolefin or other support material, for example, or may be a sealant layer. Referring to FIG.
  • Layer B is positioned proximal to Layer A with a top facial surface 214 of Layer B in adhering contact with a bottom facial surface 222 of Layer A.
  • a top facial surface 224 of Layer C is in adhering contact with the bottom facial surface 232 of Layer B.
  • the composition of Layer B comprises an ethylene/a- olefin random copolymer, a styrenic block copolymer, a tackifier, and an oil.
  • the adhesive composition of Layer B may also provide the reclose and reopen functionality to the reclose film or reclosable package. Additionally, in some embodiments, the adhesive composition does not negatively affect the quality of the package contents. For example, in one or more conventional reclosable packages, compositions present in the package may impart an unpleasant odor to the package contents. In one or more embodiments, the reclosable package does not affect the aroma, smell, odor, or other olfactory properties of the package contents.
  • the adhesive compositions of the present disclosure include reduced concentrations of styrenic block copolymers compared to conventional reclose films. Therefore, the adhesive compositions of the present disclosure and the multilayer films and packages made therewith may provide reclosability to food packaging films without negatively impacting odor or taste of the package contents.
  • the ethylene/a-olefin random copolymer of the compositions may be a copolymer of ethylene comonomer and at least one a-olefin comonomer (i.e., alpha olefin comonomer).
  • Suitable a-olefin comonomers may include those containing 3 to 20 carbon atoms (C 3 -C 20 a- olefins).
  • the a-olefin comonomer may be a C 3 -C 20 a-olefin, a C 3 -C 12 a- olefin, a C 3 -C10 a-olefin, a C 3 -C8 a-olefin, a C 4 -C 2 o a-olefin, a C 4 -Ci 2 a-olefin, a C 4 -Cio a-olefin, or a C 4 -C 8 a-olefin.
  • the ethylene/a-olefin random copolymer may be a copolymer of ethylene comonomer and one or more co-monomers selected from propylene, 1-butene, 3 -methyl- 1-butene, 1-pentene, 3 -methyl- 1-pentene, 4-methyl-l-pentene, 1-hexene, 1- septene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.
  • the ethylene/a-olefin random copolymer may be a copolymer of ethylene comonomer and 1-hexene comonomer. In one or more embodiments, the ethylene/a-olefin random copolymer may be an ethylene/octene copolymer that may be made from ethylene comonomer and octene comonomer.
  • a weight percent of ethylene monomer units in the ethylene/a-olefin random copolymer may be greater than 50 wt. % in one or more embodiments, or greater than or equal to 55 wt. % in other embodiments, or greater than or equal to 60 wt. % in yet other embodiments, or greater than or equal to 65 wt. % in yet other embodiments.
  • the ethylene/a-olefin random copolymer may include from greater than 50 wt.% to 70 wt.%, from greater than 50 wt.% to 65 wt.%, from greater than 50 wt.% to 60 wt.%, from 55 wt.% to 70 wt.%, from 55 wt.% to 65 wt.%, from 55 wt.% to 60 wt.%, from 60 wt.% to 70 wt.%, from 60 wt.% to 65 wt.%, or from 65 wt.% to 70 wt.% ethylene monomer units.
  • a weight percent of the ⁇ -olefin comonomer in the first polyethylene resin may be less than 50 wt. % in one or more embodiments, or less than or equal to 45 wt. % in other embodiments, or less than or equal to 40 wt. % in yet other embodiments, or less than or equal to 35 wt. % in yet other embodiments.
  • the ethylene/a-olefin random copolymer may have a density of less than or equal to 0.890 grams per centimeter cubed (g/cm ). In some embodiments, the ethylene/a-olefin random copolymer may have a density that is less than or equal to 0.880 g/cm , or even less than 0.87 g/cm . The density of the ethylene/a-olefin random copolymer is measured in accordance with ASTM D792. In one or more embodiments, the ethylene/a-olefin random copolymer may have a density of from 0.850 g/cm 3 to 0.890 g/cm 3.
  • the ethylene/a- olefin random copolymer may have a density of from 0.850 g/cm 3 to 0.880 g/cm 3 , from 0.850 g/cm 3 to 0.870 g/cm 3 , from 0.860 g/cm 3 to 0.890 g/cm 3 , or 0.860 g/cm 3 to 0.880 g/cm 3 .
  • the ethylene/a-olefin random copolymer may have a melting point of less than or equal to 100 degrees Celsius (°C).
  • the ethylene/a-olefin random copolymer may have a melting point of less than or equal to 95°C, less than or equal to 90°C, less than or equal to 80°C, or even less than or equal to 75°C.
  • the ethylene/a-olefin random copolymer may have a melting point of greater than room temperature, such as greater than or equal to 30°C or even greater than or equal to 40°C.
  • the ethylene/a-olefin random copolymer may have a melting point of from 30°C to 100°C, from 30°C to 95°C, from 30°C to 90°C, from 30°C to 80°C, from 30°C to 75°C, from 40°C to 100°C, from 40°C to 95°C, from 40°C to 90°C, from 40°C to 80°C, or from 40°C to 75°C.
  • the ethylene/a-olefin random copolymer may have a melt index (I 2 ), which is measured according to ASTM D1238 at 190 °C and 2.16 kg load, of from 0.2 grams per 10 minutes (g/10 min) to 8.0 g/10 min, from 0.2 g/10 min to 5.0 g/10 min, from 0.2 g/10 min to 3.0 g/10 min, from 0.2 g/10 min to 1.5 g/10 min, from 0.2 g/10 min to 1.0 g/10 min, from 0.5 g/10 min to 8.0 g/10 min, from 0.5 g/10 min to 5.0 g/10 min, from 0.5 g/10 min to 3.0 g/10 min, from 0.5 g/10 min to 1.5 g/10 min, from 0.5 g/10 min to 1.0 g/10 min, from 1.0 g/10 min to 8.0 g/10 min, from 1.0 g/10 min to 5.0 g/10 min, from 1.0 g/10 min to 3.0 g/10 min, or from 3.0
  • the ethylene/a-olefin random copolymer may have a melt index (I 2 ) of from 0.2 g/10 min to 8.0 g/10 min. In one or more other embodiments, the ethylene/a-olefin random copolymer may have a melt index (I 2 ) of from 0.5 g/10 min to 1.5 g/10 min.
  • the ethylene/a-olefin random copolymer may have a molecular weight distribution (MWD or Mw/Mn) of from 1.0 to 3.5, from 1.0 to 3.0, from 1.0 to 2.5, from 1.0 to 2.2, from 1.0 to 2.0, from 1.3 to 3.5, from 1.3 to 3.0, from 1.3 to 2.5, from 1.3 to 2.2, from 1.3 to 2.0, from 1.7 to 3.5, from 1.7 to 3.0, from 1.7 to 2.5, from 1.7 to 2.2, or from 1.7 to 2.0.
  • the ethylene/a-olefin random copolymer may have a MWD of from 1.0 to 3.5.
  • Mw is the weight average molecular weight
  • Mn is the number average molecular weight, both of which may be measured by gel permeation chromatography (GPC).
  • the dynamic melt viscosity of the ethylene/a-olefin random copolymer may be measured using Dynamic Mechanical Spectroscopy (DMS), which is described subsequently in this disclosure.
  • the ethylene/a-olefin random copolymer may have a ratio of the dynamic melt viscosity at 0.1 radians per second to the dynamic melt viscosity at 100 radians per second of less than or equal to 20 at a temperature of 110°C as determined by DMS.
  • the ethylene/a-olefin random copolymer may have a ratio of the dynamic melt viscosity at 0.1 radians per second to the dynamic melt viscosity at 100 radians per second of less than or equal to 15 at a temperature of 130°C as determined by DMS. In some embodiments, the ethylene/a-olefin random copolymer may have a ratio of the dynamic melt viscosity at 0.1 radians per second to the dynamic melt viscosity at 100 radians per second of less than or equal to 10 at a temperature of 150°C as determined by DMS.
  • the ethylene/a-olefin random copolymer may be made by gas-phase, solution-phase, or slurry polymerization processes, or any combination thereof, using any type of reactor or reactor configuration known in the art, e.g., fluidized bed gas phase reactors, loop reactors, continuous stirred tank reactors, batch reactors in parallel, series, or any combinations thereof. In some embodiments, gas or slurry phase reactors are used. In some embodiments, the ethylene/a-olefin random copolymer is made in a gas-phase or slurry process such as that described in U.S. Patent No. 8,497,330, which is herein incorporated by reference in its entirety.
  • the ethylene/a-olefin random copolymer may also be made by a high pressure, free-radical polymerization process.
  • Methods for preparing the ethylene/a-olefin random copolymer by high pressure, free radical polymerization can be found in U.S. 2004/0054097, which is herein incorporated by reference in its entirety, and can be carried out in an autoclave or tubular reactor as well as any combination thereof. Details and examples of a solution polymerization of ethylene monomer and one or more a-olefin comonomers in the presence of a Ziegler-Natta catalyst are disclosed in U.S. Pat. Nos. 4,076,698 and 5,844,045, which are incorporated by reference herein in their entirety.
  • the catalysts used to make the ethylene/a-olefin random copolymer described herein may include Ziegler-Natta, metallocene, constrained geometry, single site catalysts, or chromium-based catalysts.
  • Exemplary suitable ethylene/a-olefin random copolymers may include, but may not be limited to, AFFINITYTM EG 8100 ethylene/a-olefin random copolymer and ENGAGETM 8842 ethylene/a-olefin copolymer supplied by The Dow Chemical Company, Midland, MI.
  • the pressure sensitive adhesive composition may include from 30 wt.% to 65 wt.% ethylene/a-olefin random copolymer.
  • the adhesive composition may include from 30 wt.% to 55 wt.%, from 33 wt.% to 65 wt.%, or from 33 wt.% to 55 wt.% ethylene/a-olefin random copolymer.
  • the adhesive composition includes a styrenic block copolymer.
  • the styrenic block copolymer contains from greater than 1 wt. % to less than 50 wt.% styrene.
  • the styrenic block copolymer may include from 10 wt.%styrene to less than 50 wt.% styrene.
  • the styrene monomer may be styrene or a styrene derivative, such as alpha-methyl styrene, 4-methylstyrene, 3,5-diethylstyrene, 2-ethyl-4- benzylstyrene, 4-phenylstyrene, or mixtures thereof.
  • the styrene monomer is styrene.
  • Various olefin or diolefin (diene) comonomers are contemplated as suitable for polymerizing with the styrene.
  • the olefin comonomer may comprise C3-C20 a-olefins.
  • the diolefin comonomers may include various C 4 -C 2 o olefins such as 1,3 -butadiene, 1,3- cyclohexadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-l,3-butadiene, 2-ethyl-
  • styrenic block copolymers may include, but are not limited to, styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene/butylene-styrene block copolymers (SEBS), styrene-isobutylene- styrene block copolymers (SIBS), styrene-ethylene-propylene-styrene block copolymers (SEPS), and mixtures thereof.
  • SIS styrene-isoprene-styrene block copolymers
  • SBS styrene-butadiene-styrene block copolymers
  • SEBS styrene-ethylene/butylene-styrene block copolymers
  • SIBS styrene-isobut
  • styrenic block copolymers may include, but are not limited to, materials commercially available under the tradename "KRATON” such as KRATON D1161, KRATON D1118, KRATON G1657, and the like, available from Kraton Corp., Houston, Texas or materials commercially available under the trade name “Vector” such as 4113A, 4114A, 4213A, and the like, available from Dexco Polymers, Houston, Texas.
  • KRATON such as KRATON D1161, KRATON D1118, KRATON G1657, and the like
  • Vector such as 4113A, 4114A, 4213A, and the like, available from Dexco Polymers, Houston, Texas.
  • the styrenic block copolymer includes less than 50 wt.% styrene.
  • the stryrenic block polymer may include less than or equal to 45 wt.%, less than or equal to 40 wt.%, less than or equal to 35 wt.%, less than or equal to 30 wt.%, or even less than or equal to 25 wt.% styrene.
  • the styrenic block copolymer may have from greater than or equal to 1 wt.% to less than 50 wt.% styrene.
  • the styrenic block copolymer may have from 5 wt.% to less than 50 wt.%, from 10 wt.% to less than 50 wt.%, from 15 wt.% to less than 50 wt.%, from 20 wt.% to less than 50 wt.%, from 1 wt.% to 45 wt.%, from 1 wt.% to 40 wt.%, from 1 wt.% to 35 wt.%, from 1 wt.% to 30 wt.%, from 1 wt.% to 25 wt.%, from 5 wt.% to less than 50 wt.%, from 5 wt.% to 45 wt.%, from 5 wt.% to 40 wt.%, from 5 wt.% to 35 wt.%, from 5 wt.% to 30 wt.%, from 5 wt.% to 25 wt.%, from 5 wt
  • the styrenic block copolymer including less than 50 wt.% styrene may include an amount of non-styrenic copolymer that is sufficient to interact with the tackifier.
  • the styrenic block copolymer may be SIS and the styrenic block copolymer may include from 15 wt.% to 25 wt.% styrene.
  • the styrenic block copolymer may be SIS and may include from 20 wt.% to 25 wt.% styrene.
  • compositions disclosed herein may include from 10 wt.% to 35 wt.% styrenic block copolymer based on the total weight of the composition.
  • the compositions may include from 10 wt.% to 30 wt.% styrenic block copolymer based on the total weight of the composition.
  • the tackifier may be a resin added to the compositions disclosed herein to reduce the modulus and increase the surface adhesion of the compositions compared to the compositions without the tackifier.
  • the tackifier may be a hydrocarbon tackifier.
  • the tackifier may include, but is not limited to, non-hydrogenated aliphatic C5 (five carbon atoms) resins, hydrogenated aliphatic C5 resins, aromatic modified C5 resins, terpene resin, hydrogenated C9 resins, or combinations thereof.
  • the tackifier may be selected from the group consisting of a non-hydrogenated aliphatic C5 resin and a hydrogenated aliphatic C5 resin.
  • the composition may include a plurality of tackifiers.
  • the tackifier may have a density from 0.92 g/cm to 1.06 g/cm .
  • the tackifier may exhibit a Ring and Ball softening temperature of from 80°C to 140°C, from 85°C to 130°C, from 90°C to 120°C, from 90°C to 110°C, or from 91 0 to 100°C.
  • the Ring and Ball softening temperature may be measured in accordance with ASTM E 28.
  • the tackifier may exhibit a melt viscosity of less than 1000 Pascal second (Pa-s) at 175°C.
  • the tackifier may exhibit a melt viscosity of less than or equal to 500 Pa-s, less than or equal to 200 Pa-s, less than or equal to 100 Pa-s, or even less than or equal to 50 Pa-s at 175°C. Further, in some embodiments, the tackifier may exhibit a melt viscosity greater than or equal to 1 Pa-s or greater than or equal to 5 Pa-s at 175°C. In a some embodiments, the tackifier may exhibit a melt viscosity from 1 Pa-s to less than 100 Pa-s, or to less than 50 Pa-s at 175°C. The melt viscosity of the tackifier may be determined using dynamic mechanical spectroscopy (DMS).
  • DMS dynamic mechanical spectroscopy
  • the C5 resin for a "C5 tackifier” may be obtained from C5 feedstocks such as pentenes and piperylene.
  • the terpene resin for a tackifier may be based on pinene and d-limonene feedstocks.
  • suitable tackifiers may include, but are not limited to, tackifiers sold under the tradename PICCOTAC, REGALITE, REGALREZ, and PICCOLYTE, such as PICCOTAC 1100, PICCOTAC 1095, REGALITE R1090, and REGALREZ 11126, available from The Eastman Chemical Company, and PICCOLYTE F-105 from PINOVA.
  • compositions disclosed herein may include from 20 wt. % to 40 wt.% tackifier.
  • the compositions may have from 20 wt.% to 35 wt.%, from 20 wt.% to 30 wt.%, from 25 wt.% to 40 wt.%, from 25 wt.% to 35 wt.%, or from 25 wt.% to 30 wt.% tackifier based on the total weight of the composition.
  • the compositions disclosed herein may also include an oil.
  • the oil may include greater than 95 mole % aliphatic carbon compounds.
  • the oil may exhibit a glass transition temperature for the amorphous portion of the oil that is less than -70°C.
  • the oil can be a mineral oil.
  • suitable oils may include, but are not limited to, mineral oil sold under the tradenames HYDROBRITE 550 (Sonneborn), PARALUX 6001 (Chevron), KAYDOL (Sonneborn), BRITOL 50T (Sonneborn), CLARION 200 (Citgo), CLARION 500 (Citgo), or combinations thereof.
  • the oil may comprise a combination or two or more oils described herein.
  • the compositions disclosed herein may include from greater than 0 wt.% to 8 wt.% oil.
  • the compositions may include from greater than 0 wt.% to 7 wt.%, from 3 wt.% to 8 wt.%, from 3 wt.% to 7 wt.%, from 5 wt.% to 8 wt.%, or from 5 wt.% to 7 wt.% oil based on the total weight of the composition.
  • the present compositions may optionally include one or more additives.
  • compositions further comprise one or more additional polymers.
  • Additional polymers include, but are not limited to, ethylene-based polymers and propylene-based polymers.
  • compositions disclosed herein may include from 30 wt.% to 65 wt.% ethylene/a-olefin random copolymer, from 10 wt.% to 35 wt.% styrenic block copolymer, from 20 wt.% to 40 wt.% tackifier, and from greater than 0 wt.% to 8 wt.% oil.
  • the compositions may include from 33 wt.% to 55 wt.% ethylene/a-olefin random copolymer, from 10 wt.% to 30 wt.% styrenic block copolymer, from 25 wt.% to 30 wt.% tackifier, and from 5 wt.% to 7 wt.% oil.
  • the compositions may have an overall density of less than or equal to 0.930 g/cm 3 , or less than or equal to 0.920 g/cm 3. In some embodiments, the compositions may have an overall density of from 0.880 g/cm 3 to 0.930 g/cm 3 , from 0.880 g/cm 3 to 0.920 g/cm 3 , from 0.890 g/cm 3 to 0.930 g/cm 3 , or from 0.89 g/cm 3 to 0.92 g/cm 3 .
  • the compositions may exhibit an overall melt index (I 2 ) of from 2 grams per 10 minutes (g/10 min) to 15 g/10 min.
  • the compositions may exhibit an overall melt index (I 2 ) of from 2 g/10 min to 14 g/10 min, from 2 g/10 min to 12 g/10 min, from 2 g/10 min to 10 g/10 min, from 3 g/10 min to 15 g/10 min, from 3 g/10 min to 14 g/10 min, from 3 g/10 min to 12 g/10 min, from 3 g/10 min to 10 g/10 min, from 5 g/10 min to 15 g/10 min, from 5 g/10 min to 14 g/10 min, from 5 g/10 min to 12 g/10 min, from 5 g/10 min to 10 g/10 min, from 7 g/10 min to 15 g/10 min, from 7 g/10 min to 14 g/10 min, from 7 g/10 min to 12 g/10 min, or from 7 g/10 min to
  • the dynamic melt viscosity may be determined using Dynamic Mechanical Spectroscopy (DMS) at a various testing temperatures and testing frequency.
  • the compositions may exhibit a dynamic melt viscosity of from 1,000 Pa-s to 1,400 Pa-s measured using DMS at a temperature of 190 °C and a frequency of 1 Hz.
  • the compositions may exhibit a dynamic melt viscosity of from 3,200 Pa-s to 4,000 Pa-s measured using DMS at a temperature of 150 °C and a frequency of 1 Hz.
  • the compositions may exhibit a dynamic melt viscosity of from 7,400 Pa-s to 7,800 Pa-s measured using DMS at a temperature of 130 °C and a frequency of 1 Hz.
  • the compositions may exhibit a dynamic melt viscosity of from 12,400 Pa-s to 17,200 Pa-s measured using DMS at a temperature of 110 °C and a frequency of 1 Hz.
  • the compositions disclosed herein may exhibit a melt temperature of less than or equal to 100°C, less than or equal to 90°C, or even less than or equal to 80°C. In some embodiments, the compositions may exhibit a melt temperature of from 60°C to 100°C, from 60°C to 90°C, from 60°C to 80°C, from 70°C to 100°C, or from 70°C to 90°C. In some embodiments, the compositions may exhibit no melting peaks above 100 °C.
  • compositions may exhibit an initial internal cohesion force of less than or equal to 40 newtons/inch (N/in), less than or equal to 37 N/in, less than 35 N/in, or even less than 30 N/in after being heat sealed at a heat sealing temperature of 150 °C.
  • the initial internal cohesion force of the compositions may be determined according to the test method for peel strength described herein.
  • the compositions may exhibit an initial internal cohesion force of from 25 N/in to 40 N/in, from 25 N/in to 37 N/in, from 25 N/in to 35 N/in, from 27 N/in to 40 N/in, from 27 N/in to 37 N/in, from 27 N/in to 35 N/in, from 30 N/in to 40 N/in, from 30 N/in to 37 N/in, or from 30 N/in to 35 N/in after being heat sealed at a heat sealing temperature of 130 °C.
  • the compositions may exhibit a reclose peel adhesion force of greater than or equal to 1.0 N/in after being heat sealed at a heat seal temperature of 150 °C, initially opened, and after experiencing at least 4 reclose-reopen cycles. In some embodiments, the compositions may exhibit a reclose peel adhesion force of greater than or equal to 1.5 N/in, greater than or equal to 2.0 N/in, or even greater than 2.5 N/in after being heat sealed at a heat seal temperature of 150 °C, initially opened, and after experiencing at least 4 reclose-reopen cycles.
  • the compositions may exhibit a reclose peel adhesion force of from 2.0 N/in to 10.0 N/in, from 2.0 N/in to 7.0 N/in, from 2.0 N/in to 5.0 N/in, from 2.5 N/in to 10.0 N/in, from 2.5 N/in to 7.0 N/in, or from 2.5 N/in to 5.0 N/in after being heat sealed at a heat seal temperature of 150 °C, initially opened, and after experiencing at least 4 reclose-reopen cycles.
  • the compositions disclosed herein may be compounded using a single stage twin- screw extrusion process or any other conventional blending or compounding process.
  • compositions disclosed herein may be incorporated into a multilayer film, which may provide reclose functionality to packaging made from the multilayer film.
  • the multilayer film may include at least three layers: a sealing layer forming a facial surface of the multilayer film, a reclose layer in adhering contact with the sealing layer, and at least one supplemental layer in adhering contact with the reclose layer.
  • the sealing layer may seal the multilayer film to a substrate, such as a surface of a container, another flexible film, or to itself, for example.
  • the reclose layer once activated by exerting an initial opening force on the multilayer film, may provide reclose/reopen functionality to the multilayer film.
  • At least one supplemental layer may provide structural support to the multilayer film or may provide an additional sealing layer.
  • the reclose film 200 is illustrated that includes at least three layers: Layer A, Layer B, and Layer C.
  • the reclose film 200 will be described relative to an embodiment having three layers; however, the multilayer film may have more than three layers, such as four, five, six, seven, eight, or even more than 8 layers.
  • the multilayer film may have 4 layers: Layer A, Layer B, Layer C, and Layer D. Reclose films with more than 4 layers are also contemplated.
  • the reclose film 200 may have a film top facial surface 202 and a film bottom facial surface 204.
  • each of the layers A, B, and C may have opposing facial surfaces, such as a top facial surface and a bottom facial surface.
  • top refers to the facial surface of the multilayer oriented toward the Layer A side of the reclose film 200
  • bottom refers to the opposite side of the reclose film 200 oriented away from the Layer A side of the reclose film 200.
  • Layer A may have a top facial surface 212 and a bottom facial surface 214.
  • the top facial surface 212 of Layer A may be the film top facial surface 202 of the reclose film 200.
  • the bottom facial surface 214 of Layer A may be in adhering contact with the top facial surface 222 of Layer B.
  • Layer A is a sealing layer that includes a sealing composition capable of sealing the film top facial surface 202 of the reclose film 200 to a surface of a substrate or to itself.
  • the sealing composition may be a heat sealing composition.
  • the sealing composition may be capable of hermitically sealing the film top facial surface 202 of the reclose film 200 to a surface of a substrate or to itself.
  • the sealing composition may include a polyolefin.
  • the sealing composition of Layer A may include at least one of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra-low density polyethylene (ULDPE), ethylene vinyl acetate (EVA), ionomers, polyolefin elastomers, other sealing composition, or combinations of these.
  • sealing compositions may include, but are not limited to, AFFINITYTM polyolefin elastomer supplied by The Dow Chemical Company, Midland, MI.
  • Layer A does not include the composition previously described in this disclosure.
  • the sealing composition of Layer A has an internal cohesive strength greater than the internal cohesive strength of the composition of Layer B.
  • the sealing composition of Layer A may have an internal cohesion strength that is greater than the internal cohesion strength of the composition of Layer B.
  • the initial opening force causes the sealing composition of Layer A to fail in a direction generally perpendicular to the reclose film 200.
  • Failure of the sealing composition of Layer A may enable the composition of Layer B to cohesively fail in a direction generally parallel to the reclose film 200 to activate the reclose functionality. Therefore, the internal cohesion strength of Layer A may be low enough so that the magnitude of the opening force needed to initially open the reclose film 200 and activate the reclose and reopen functionality is not excessive.
  • Layer B includes the top facial surface 222 and a bottom facial surface 224.
  • the top facial surface 222 of Layer B may be in adhering contact with the bottom facial surface 214 of Layer A.
  • the bottom facial surface 224 of Layer B may be in adhering contact with a top facial surface 232 of Layer C.
  • Layer B is positioned adjacent to Layer A and in adhering contact with Layer B, and Layer B is disposed between Layer A and Layer C.
  • Layer B comprises the compositions previously described in this disclosure that include the ethylene/a-olefin random copolymer, styrenic block copolymer, tackifier, and oil.
  • Layer C includes the top facial surface 232 and a bottom facial surface 234.
  • the top facial surface 232 of Layer C may be in adhering contact with the bottom facial surface 224 of Layer B.
  • the bottom facial surface 234 of Layer C may comprise the film bottom facial surface 204 of the reclose film 200, such as when the reclose film 200 includes three layers.
  • the bottom facial surface 234 of Layer C may be in adhering contact with a top facial surface of a subsequent layer.
  • the bottom facial surface 234 of Layer C may be in adhering contact with a top facial surface 242 of Layer D.
  • Layer C may be a structural layer that may provide strength and stiffness to the reclose film 200.
  • Layer C may include a polymer or copolymer comprising at least an ethylene monomer, such as, but not limited to high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), or combinations of these.
  • Layer C may include LLDPE.
  • Layer C may include other polymer film materials, such as nylon, polypropylene, polyesters such as polyethylene terephthalate (PET) for example, polyvinyl chloride, other thermoplastic polymers, or combinations of these.
  • Layer C may include additional structural materials, such as nylon for example.
  • Layer C may be a sealant layer that includes any of the sealant compositions previously discussed in relation to Layer A.
  • the reclose film 200 may be a flexible film, which may enable the reclose film 200 to conform its shape to seal to various substrates and substrate surfaces.
  • Additional supplemental layers may be added to the bottom facial surface 234 of Layer C to impart any of a number of properties to the multilayer film.
  • a reclose film 300 that includes four layers is schematically depicted.
  • reclose film 300 may include Layer A, Layer B, Layer C, and Layer D.
  • Layer A may again be the sealing layer
  • Layer B may be the reclose layer in adhering contact with the sealing layer (Layer A).
  • the reclose film 300 depicted in FIG. 5 includes at least two supplemental layers; Layer C and Layer D.
  • Layer C may have the top facial surface 232 in adhering contact with the bottom facial surface 224 of Layer B.
  • the bottom facial surface 234 of Layer C may be in adhering contact with the top facial surface 242 of Layer D.
  • the bottom facial surface 244 of Layer D may be the film bottom facial surface 204 of the reclose film 300.
  • the bottom facial surface 244 of Layer D may be in adhering contact with the top facial surface of another supplemental layer.
  • Each of the supplemental layers may include different materials or combinations of materials that provide different properties to the reclose film 300, such as structural support, insulating properties, moisture resistance, chemical resistance, tear or puncture resistance, optical properties, sealing capability, gas permeability or impermeability properties, friction resistance, other properties, or combinations of these.
  • Layer C may include materials that provide structural support to the multilayer film
  • Layer D may include a sealing composition, such as the sealing compositions previously described for Layer A, to enable sealing of the film bottom facial surface 204 of the reclose film 300 to a second substrate.
  • Layers C and D, as well as other supplemental layers included to the bottom portion of the reclose film 300 may provide a plurality of other functionalities to the reclose film 300.
  • each of the plurality of layers may be coextruded to form the reclose films 200, 300.
  • the reclose films 200, 300 may be produced using a blown film process.
  • the reclose films 200, 300 may be produced using cast film processes.
  • Other conventional processes for producing multilayer films may also be employed to produce the reclose films 200, 300.
  • the reclose film 200 may be initially sealed to a surface 252 of a substrate 250.
  • the substrate 250 may be a rigid substrate, such as a rigid container made from plastic, metal, glass, ceramic, coated or uncoated cardboard (e.g., fiberboard, paperboard or other rigid structure made from wood pulp), other rigid material, or combinations of these.
  • the substrate 250 may be a non-rigid or flexible substrate, such as a polymer film, metal foil, paper, natural or synthetic fabric, other flexible substrate, or combinations of these.
  • the substrate 250 may include another multilayer polymer film.
  • the substrate 250 may be the reclose film 200 itself, such as by folding the reclose film 200 and sealing the reclose film 200 to itself or by providing two separate sheets or webs of the reclose film 200.
  • the reclose film 200 may be sealed to the surface 252 of the substrate 250 by contacting the top facial surface 212 of Layer A with a surface 252 of the substrate 250 and applying heat, pressure, or a combination of heat and pressure to the reclose film 200 to seal the Layer A, which is the sealing layer of the reclose film 200, to the surface 252 of the substrate 250.
  • Layer A of the reclose film 200 may be heat sealed to the substrate 250.
  • Heat sealing may be accomplished by conventional heat sealing processes which may be operated at heat sealing temperatures of greater than about 130°C.
  • Layer A of the reclose film 200 may be heat sealed to the surface 252 of the substrate 250 at a heat sealing temperature of from 100°C to 180°C.
  • the heat sealing temperature may be from 100°C to 160°C, from 100°C to 150°C, from 120°C to 180°C, from 120°C to 160°C, from 120°C to 150°C, from 130°C to 180°C, from 130°C to 160°C, or from 130°C to 150°C.
  • only a portion of Layer A of the reclose film 200 is sealed to the surface 252 of the substrate 250 to form a sealed region 254.
  • the portions of the reclose film 200 in which Layer A is not sealed to the surface 252 of the substrate 250 may define an unsealed region 256 of the reclose film 200.
  • Layer A of the reclose film 200 is not sealed to the surface 52 of the substrate 250 and may be free to move in a direction normal to the surface 252 of the substrate 250 so that Layer A of the reclose film 200 is spaced apart from the substrate 250 in the unsealed region 256.
  • the reclose film 200 in the unsealed region 256, may be spaced apart from the substrate 250 to define a volume between the reclose film 200 and the substrate 250.
  • the unsealed region 256 may provide a tab 258 that may enable a force to be exerted on the reclose film 200 relative to the substrate 250.
  • the sealed regions 254 may exhibit a seal integrity sufficient to prevent passage of particulates between the multilayer film 200 and the substrate 250 in the sealed region 254. In other embodiments, seal integrity of the sealed regions 254 may be sufficient to prevent passage of liquids between the multilayer film 200 and the substrate 250 in the sealed region 254. In still other embodiments, seal integrity of the sealed regions 254 may be sufficient to prevent passage of moisture between the multilayer film 200 and the substrate 250 in the sealed region 254. In still other embodiments, seal integrity of the sealed regions 254 may be sufficient to prevent passage of are between the multilayer film 200 and the substrate 250 in the sealed region 254.
  • a bond strength between the bottom facial surface 214 of Layer A and the top facial surface 222 of Layer B may be greater than a cohesive strength of the adhesive composition of Layer B.
  • a bond strength between the bottom facial surface 224 of Layer B and the top facial surface 232 of Layer C may be also be greater than an internal cohesion strength of the adhesive composition of Layer B.
  • the bond strength of the top facial surface 212 of Layer A to the surface 252 of the substrate 250 may be greater than an internal cohesion strength of the composition of Layer B. Therefore, the sealing composition of Layer A does not provide reclose functionality to the reclose film 200.
  • the reclose film 200 does not exhibit reclose functionality until after an initial opening force is applied to the reclose film 200 to separate a portion of the reclose film 200 from the substrate 250.
  • the reclose functionality of the reclose film 200 may be activated by applying an initial opening force Fl on the reclose film 200.
  • the initial opening force Fl may be applied in a direction generally perpendicular to the film top facial surface 202 of the reclose film 200.
  • the initial opening force Fl may be greater than a threshold force, at which separation of the reclose film 200 occurs to activate the reclose functionality.
  • the initial opening force Fl may be sufficient to cause Layer A to fail at an interface 260 between the sealed region 254 and the unsealed region 256 of the reclose film 200.
  • the initial opening force Fl for the reclose film 200 may be less than or equal to about 40 newtons/inch (N/in), less than less than or equal to 37 N/inch, less than or equal to 35 N/inch, or even less than or equal to 30 N/inch after being heat sealed at a heat sealing temperature of 150°C.
  • the initial opening force Fl may be determined according to the Peel Adhesion Test as described herein.
  • the initial opening force Fl of the multilayer film may be determined according to the test method for peel strength described herein at the heat sealing temperature of 130°C.
  • the initial opening force Fl for the reclose film 200 may be from 25 N/inch to 40 N/inch, from 25 N/inch to 37 N/inch, from 25 N/inch to 35 N/inch, from 27 N/inch to 40 N/inch, from 27 N/inch to 37 N/inch, from 27 N/inch to 35 N/inch, from 30 N/inch to 40 N/inch, from 30 N/inch to 37 N/inch, or from 30 N/inch to 35 N/inch after the multilayer film is heat sealed at a heat sealing temperature of 130°C.
  • Layer A ruptures at an interface 260 of the sealed region 254 and the unsealed region 256.
  • Layer A may rupture in a direction from the bottom facial surface 214 to the top facial surface 212 of Layer A (e.g., generally perpendicular to the film top facial surface 202 or in the +/-Z direction of the coordinate axis of FIG. 5B).
  • the internal cohesion strength of the composition of Layer B is less than the initial opening force and less than the bond strengths between the top facial surface 222 of Layer B and the bottom facial surface 214 of Layer A, and between the bottom facial surface 224 of Layer B and the top facial surface 232 of Layer C.
  • Layer B in the sealed region 254 cohesively fails in a direction generally parallel to the film top facial surface 202.
  • Cohesive failure of Layer A results in a first portion 262 of the composition of Layer B coupled to the bottom facial surface 214 of Layer A and a second portion 264 of the composition of Layer B coupled to the top facial surface 232 of Layer C.
  • the composition of Layer B covers both the top facial surface 232 of Layer C and the bottom facial surface 214 of Layer A.
  • the portion of Layer A in the sealed region 254, including the opened portion of the sealed region 254, remains sealed to the substrate 250 (i.e., the top facial surface 212 of Layer A remains sealed to the surface 252 of the substrate 250 in the sealed region 254, including the opened portion).
  • the sealed region 254 may bounded by the unsealed region 256 on one side of the sealed region 254 and a second unsealed region 257 on the other side of the sealed region.
  • the initial opening force Fl may cause Layer A to rupture at the interface 260 of the sealed region 254 and the unsealed region 256 in a direction generally perpendicular to the film top facial surface 202, as previously described in relation to FIG. 6B. As shown in FIG.
  • the opening force Fl may cause Layer B to cohesively fail in a direction generally parallel to the film top facial surface 202, as previously described.
  • the initial opening force Fl may cause Layer A to rupture again at the second interface 261 between the sealed region 254 and the second unsealed region 257.
  • Layer A may rupture in a direction generally perpendicular to the film top facial surface 202.
  • Initial opening of the reclose film 200 activates the reclose functionality of the multilayer film resulting in the first portion 262 of the composition of Layer B on the bottom facial surface 214 of Layer A and the second portion 264 of the composition of Layer B on the top facial surface 232 of Layer C.
  • the first portion 262 of the composition of Layer B may be returned into contact with the second portion 264 of the composition of Layer B and a reclose pressure F2 may be applied to the reclose film 200 in the sealed region 254.
  • the reclose pressure F2 may be applied to the reclose film 200 in a direction generally perpendicular to the film bottom facial surface 204.
  • the reclose pressure F2 may be sufficient to cause the first portion 262 and the second portion 264 of the composition of Layer B to re-adhere to reform Layer B.
  • the reclose pressure F2 may be less than or equal to 40 N/inch, less than or equal to 30 N/inch, less than or equal to 20 N/inch, or even less than or equal to 10 N/inch.
  • Applying the reclose pressure F2 to the multilayer film causes the first portion 262 and the second portion 264 of the composition of Layer B to re-adhere. Re-adherence of the first portion 262 and the second portion 264 of the composition to form a contiguous Layer B , may reseal the sealed region 254 of the multilayer film.
  • the reclose film 200 may be reopened by applying a reopen force F3 to the reclose film 200.
  • Reopen force F3 may be applied to the multilayer film in a direction generally perpendicular to the film top facial surface 202.
  • the reopen force F3 may be applied by gripping the reclose film 200 in the unsealed region 256 and pulling the reclose film 200 away from the substrate 250.
  • Application of the reopen force F3 may cause the composition of Layer B to cohesively fail in a direction parallel to the film top facial surface 102.
  • the reopen force F3 may be sufficient to cause the composition of Layer B to cohesively fail.
  • reopen force F3 may be greater than or equal to 1 N/inch, greater than or equal to 1.5 N/inch, greater than or equal to 2.0 N/inch, greater than or equal to 2.5 N/inch, or even greater than or equal to 3 N/inch for the reclose film 200 heat sealed to the substrate 250 at a heat seal temperature of 130°C.
  • the reopen force F3 may be determined according to the Peel Adhesion Test described herein.
  • the reclose film 200 may be subjected to multiple cycles of reopening and reclosing. After multiple reopen/reclose cycles, the reclose film 200 may exhibit a reopen force F3 of greater than or equal to 1.5 N/inch, greater than or equal to 2.0 N/inch, greater than or equal to 2.5 N/inch, or even greater than 3.0 N/inch.
  • the reclose film 200 which is initially heat sealed to the substrate 250 at a heat seal temperature of 130°C, may exhibit a reopen force F3 after at least four reopen/reclose cycles of greater than 2.0 N/inch.
  • the reclose film 200 may exhibit a reopen force of from 2.0 N/inch to 10.0 N/inch, from 2.0 N/inch to 7.0 N/inch, from 2.0 N/inch to 5.0 N/inch, from 2.5 N/inch to 10.0 N/inch, from 2.5 N/inch to 7.0 N/inch, or from 2.5 N/inch to 5.0 N/inch after being heat sealed at a heat seal temperature of 130°C, initially opened, and after experiencing at least 4 reclose-reopen cycles.
  • the rear wall 120 of a reclosable package 100 comprises a reclose film.
  • the interior surface of the rear wall 120 may comprise the top facial surface 212 of Layer A.
  • the exterior surface of the rear wall 120 may comprise a bottom facial surface 234 of Layer C.
  • Layer B is disposed between Layer A and Layer C with a top facial surface 214 of Layer B in adhering contact with a bottom facial surface of Layer A 222 and a top facial surface 224 of Layer C is in adhering contact with the bottom facial surface 232 of Layer B.
  • the top facial surface 212 of Layer A may be sealed to the exterior surface of the front wall 110.
  • the application of an opening force to the rear wall 120 in a direction away from the front wall 110 is operable to cause the cohesive failure of Layer B, separating a portion of the rear wall 120 from the front wall 110.
  • the cohesive failure of Layer B after the cohesive failure of Layer B, at least part of Layer B is disposed on the front wall 110 and at least part of Layer B is disposed on the rear wall 120.
  • the front wall 110 and the rear wall 120 of the reclosable package 100 comprise a reclose film.
  • the exterior surface of the front wall 110 may comprise the top facial surface 212 of Layer A ⁇ .
  • the interior surface of the front wall 110 may comprise a bottom facial surface 234 of Layer Q.
  • Layer Bi is disposed between Layer Ai and Layer Ci with a top facial surface 214 of Layer Bi in adhering contact with a bottom facial surface 222 of Layer Ai and a top facial surface 224 of Layer Ci is in adhering contact with the bottom facial surface 232 of Layer Bi.
  • the front wall 110 of the reclosable package 100 comprises a reclose film.
  • the exterior surface of the front wall 110 may comprise the top facial surface 212 of Layer A 2 .
  • the interior surface of the front wall 110 may comprise a bottom facial surface 234 of Layer C 2 .
  • Layer B 2 is disposed between Layer A 2 and Layer C 2 with a top facial surface 214 of Layer B 2 in adhering contact with a bottom facial surface 222 of Layer A 2 and a top facial surface 224 of Layer C 2 is in adhering contact with the bottom facial surface 232 of Layer B 2 .
  • Layer Ai may be in adhering contact with Layer A 2 .
  • the application of an opening force proximate to the closure region 150 is operable to cause the cohesive failure of either Layer Bi or Layer B 2 , separating a portion of the rear wall 120 from the front wall 110.
  • the closure region 150 comprises a reclose film disposed between the rear wall 120 and the front wall 110.
  • both the Layer A and the Layer C may be sealant layers.
  • a top facial surface 212 of the Layer A may be in adhering contact with the interior surface of the rear wall 120 and a bottom facial surface 234 of Layer C may be in adhering contact with the exterior surface 112 of the front wall 110.
  • Layer B is disposed between Layer A and Layer C with a top facial surface 214 of Layer B in adhering contact with a bottom facial surface 222 of Layer A and a top facial surface 224 of Layer C is in adhering contact with the bottom facial surface 232 of Layer B.
  • the application of an opening force proximate to the closure region 150 is operable to cause the cohesive failure of either Layer Bi or Layer B 2 , separating a portion of the rear wall 120 from the front wall 110.
  • seal regions 160 may be formed by the selective application of heat, pressure, or both to areas of the closure region 150. For example, applying heat, pressure, or both to an area or areas of the closure region 150 may result in a seal region 160 being formed in the area or areas. Conversely, an unsealed region 170 or regions may develop in areas of the closure region 150 where heat or pressure were not applied. In one or more embodiments, heat, pressure, or both may be applied in a repeating geometric pattern within the closure region 150 to form a repeating geometric pattern of seal regions 160.
  • the application of an opening force is operable to separate at least part of the front wall 110 from the rear wall 120, breaking the continuous seal between the front wall 110 and the rear wall 120 across a width wi of the reclosable package 100.
  • an opening force is applied proximate to the closure region 150, at least part of the front wall 110 is separated from the rear wall 120.
  • the front wall 110 and rear wall 120 may be separated across the entire width w, however, the front wall 110 and rear wall 120 are still sealed together throughout the border seal 138.
  • contacting the front wall 110 to the rear wall 120 proximate to the closure region 150 and applying a closing pressure proximate to the closure region 150 is operable to reform the seal between the front wall 110 to the rear wall 120 across the width w 2 of the closure region 150.
  • the magnitude of the opening force required to separate at least part of the front wall from the rear wall is largely dependent on the seal geometry of the closure region 150.
  • the magnitude of the opening force required can be tuned.
  • the magnitude of the closing pressure required to reform the seal between the front wall 110 and rear wall 120 across a width Wi,w 2 is also largely dependent on the seal geometry of the closure region 150.
  • the magnitude of the closing pressure required can be tuned.
  • the closure region 150 comprises a repeating geometric pattern of seal regions as shown in FIGS. 1A-1C.
  • the repeating geometric patterns may include, but are not limited to, triangles, quadralaterals, trapezoids, parallelagrams, rhombi, pentagons, hexagons, tessellating polygons, other polygons, circles, ovoids, ellipses, spirals, shapes comprising right angles, or combinations thereof.
  • any imprint, emboss, design, trademark, emblem, or icon may be incorporated into the closure region 150 and defined by a plurality of seal regions 160, unsealed regions 170, or both. It should be understood, that by making modifications to the seal bar, a machining component that applies heat, pressure, or both to the closure region 150, and pattern or design of seal regions 160 or unsealed regions 170 may be incorporated into the closure region 150.
  • the area fraction of seal regions 160, Xs is defined as the total combined area of all seal regions 160 divided by the total area of the closure region 150.
  • the area fraction of unsealed regions 170, Xu is defined as the total combined area of all unsealed regions 170 divided by the total are of the closure region 150.
  • the seal fraction as defined as the ratio of the Xs to the Xu. The seal fraction is always a positive number and as the seal fraction increases so does the initial opening force required to break the continuous seal.
  • the walls of the reclosable package comprise a flexible film.
  • the film may be formed by any conventional means known in the art including, but not limited to, blown film extrusion, cast film extrusion, or other extrusion techniques known in the art.
  • the forming of the film further utilizes coextrusion, a process in which multiple layers of material may be extruded simultaneously.
  • coextrusion applications multiple layers of different types of material may be extruded simultaneously. Techniques of coextrusion may be applied to any conventional methods known in the art including, but not limited to blown film extrusion or cast film extrusion.
  • the film after the film is formed, but before it is incorporated into a package, the film may be laminated. In other embodiments, the film is not laminated prior to the formation of the package.
  • FIGS. 2A-3B illustrate only a few examples of reclosable package designs that can incorporate the reclosable film and compositions according to embodiments of the present disclosure.
  • a person of ordinary skill in the art can readily identify other package types, shapes, and sizes in which the reclosable film and composition disclosed herein may be incorporated.
  • the reclosable film and/or compositions may be incorporated into package shapes and sizes for which zippers or other mechanical means have been used to provide reclosability to the package.
  • the reclosable films and compositions may be incorporated into a broad range of package types and shapes that include at least one flexible film.
  • Examples of these packaging types may include, but are not limited to tray packaging; pouch packaging such as pillow pouches, vertical form fill and seal (VFFS) packaging, horizontal form fill and seal packages, stand-up pouches, or other pouches; bags; boxes; or other type of packaging.
  • the reclosable films and compositions may be incorporated into primary packaging or secondary packaging, such as overwraps, bags, or other secondary packaging.
  • Other packaging types, shapes and sizes having the reclosable film and/or compositions disclosed herein are also contemplated.
  • the reclosable packaging disclosed herein may be used to package food products, beverages, consumer goods, personal care items, or other articles.
  • Food products that may be packaged using the reclosable packaging disclosed herein may include particular food products, such as sugar, spices, flour, coffee, or other particulates; solid food products; such as meats, cheeses, snacks, vegetables, baked goods, pet food, pasta, or other solid food products; liquid food products, such as but not limited to milk, soup, beverages, or other liquid food products; and/or bulk food items such as but not limited to rice, dog food, flour or other grains, or other bulk food items.
  • Consumer goods that may be packaged using the reclosable packaging may include but are not limited to consumer electronics, hardware, toys, sporting goods, plastic utensils, autoparts, batteries, cleaning supplies, software packages, salt, or other consumer goods.
  • the reclosable packages disclosed herein may also be incorporated into post-consumer storage bags, such as food storage bags or freezer bags. A person of ordinary skill in the art can recognize many other potential uses for the reclosable packaging disclosed herein.
  • compositions of the following examples and comparative examples were compounded using a single stage twin-screw extrusion process.
  • the compounding operation is performed on a Century- ZSK-40 45.375 length-to-diameter ratio (L/D) ( Eleven Barrels) extruder using one screw design with one oil injector, in barrel 4.
  • L/D length-to-diameter ratio
  • the extruder has a maximum screw speed of 1200 rpm.
  • the polymers and the PICCOTAC tackifier were fed into the main feed throat of the extruder.
  • the HYDROBRITE 550 process oil is added through an injection port at barrel 4.
  • the compound is pelletized using an underwater Gala system, which is equipped with a 12 hole (2.362 mm hole diameter) Gala die with 6 holes plugged, and a 4 blade hub cutter. Soap and antifoam were added to the water bath as needed to prevent clumping. The pellets were collected and dusted with 2000 ppm POLYWAX 2000 (available from Baker Hughes), and then dried under nitrogen purge for 24 hours. Screw speed is set at 180 RPM for all the samples.
  • Temperature profile is set as follows: 100 °C (zone 1), 100 °C (zone 2), 180 °C (zone 3), 180 °C (zone 4), 160 °C (zone 5), 160 °C (zone 6), 110 °C (zone 7), 110 °C (zone 8), 90 °C (zone 9), 90 °C (zone 10), and 90 °C (zone 11), with a die temperature of 140 °C.
  • Table 1 below includes properties of commercial polymers used in the Examples that follow.
  • VECTOR® 4113 A Melt Index (I 2 ) g/10 Density (g/cc) Supplier
  • Example 1 Example Composition
  • a composition according to the present disclosure was made by combining 43.4 wt.% ethylene/a-olefin random copolymer, 20 wt.% styrenic block copolymer, 30 wt.% tackifier, and 6.6 wt.% mineral oil.
  • the ethylene/a-olefin random copolymer was ENGAGETM 8842.
  • the styrenic block copolymer was VECTOR 4113 A styrene-isoprene triblock copolymer, which had a styrene content of 18 wt.%, and a diblock content of 42 wt.%.
  • the tackifier was PICCOTAC 1100 C5 tackifier available from Eastman Chemical Company.
  • the tackifier has a ring and ball softening point of 100 °C and a Mw of 2900.
  • the mineral oil was HYDROBRITE 550 mineral oil available from Sonneborn and exhibited a density of 0.87 g/cm and paraffinic carbon content of about 70 wt.%.
  • Example 1 The individual constituents of the composition of Example 1 were compounded according to the previously described single stage twin-screw extrusion process. The composition of Example 1 was then tested for density, melt index (I 2 ) at a temperature of 190 °C and a load of 2.16 kg, and melt flow rate at a temperature of 230 °C and a load of 2.16 kg. The results for the density, melt index (I 2 ), and melt flow rate for the composition of Example 1 are provided below in Table 2. Comparative Example 2: Comparative Adhesive Composition Formulated with Olefin Block Copolymer
  • Comparative Example 2 a comparative adhesive composition was produced using an olefin block copolymer in place of the ethylene/a-olefin random copolymer of Example 1.
  • the composition of Comparative Example 2 included 43.4 wt.% olefin block copolymer, 20 wt.% of the styrenic block copolymer, 30 wt.% tackifier, and 6.6 wt.% mineral oil.
  • the olefin block copolymer was INFUSETM.
  • the styrenic block copolymer, tackifier, and mineral oil in Comparative Example 2 were the same as described above for Example 1.
  • Comparative Example 2 The individual constituents of Comparative Example 2 were compounded using the previously described single stage twin-screw extrusion process.
  • the composition of Comparative Example 2 was tested for density, melt index (I 2 ) at a temperature of 190 °C and a load of 2.16 kg, and melt flow rate at a temperature of 230 °C and a load of 2.16 kg.
  • the results for the density, melt index (I 2 ), and melt flow rate for the composition of Comparative Example 2 are provided below in Table 2.
  • Comparative Example 3 Comparative Adhesive Composition Formulated with a Lesser Amount of Olefin Block Copolymer.
  • Comparative Example 3 a comparative adhesive composition was produced using an olefin block copolymer in place of the ethylene/a-olefin random copolymer of Example 1.
  • the composition of Comparative Example 3 included less olefin block copolymer and more styrenic block copolymer compared to the composition of Comparative Example 2.
  • Comparative Example 3 was prepared to investigate the effect of increasing the amount of the styrenic block copolymer in the adhesive composition.
  • the composition of Comparative Example 3 included 33.4 wt.% olefin block copolymer, 30 wt.% of the styrenic block copolymer, 30 wt.% tackifier, and 6.6 wt.% mineral oil.
  • the olefin block copolymer was INFUSETM 9107.
  • the styrenic block copolymer, tackifier, and mineral oil were the same as described above for Example 1.
  • Comparative Example 3 The individual constituents of Comparative Example 3 were compounded using the previously described single stage twin-screw extrusion process.
  • the composition of Comparative Example 3 was tested for density, melt index (I 2 ) at a temperature of 190 °C and a load of 2.16 kg, and melt flow rate at a temperature of 230 °C and a load of 2.16 kg.
  • the results for the density, melt index (I 2 ), and melt flow rate for the composition of Comparative Example 3 are provided below in Table 2.
  • Comparative Example 4 a commercially available pressure sensitive adhesive composition marketed as providing reclose capability to multilayer film compositions was obtained.
  • the commercially available composition comprised a styrene-isoprene-styrene block copolymer, hydrocarbon tackifier, and talc.
  • the commercially available composition did not include a polyethylene component, such as a polyethylene/a-olefin copolymer.
  • the commercially available adhesive composition was tested for density, melt index (I 2 ) at a temperature of 190 °C and a load of 2.16 kg, and melt flow rate at a temperature of 230 °C and a load of 2.16 kg. The results for the density, melt index (I 2 ), and melt flow rate for the composition of Comparative Example 4 are provided below in Table 2.
  • Comparative Example 5 Comparative Adhesive Composition Formulated with Styrenic Block Copolymer, Tackifier, and Oil
  • Comparative Example 5 a comparative adhesive composition was produced using a styrenic block copolymer without the ethylene/a-olefin random copolymer of Example 1.
  • the composition of Comparative Example 5 included 64.3 wt.% styrenic block copolymer, 30 wt.% tackifier, and 6.6 wt.% mineral oil.
  • the styrenic block copolymer was VECTOR® 4213A SIS triblock/SI diblock copolymer.
  • the tackifier and mineral oil were the same as described above for Example 1.
  • Comparative Example 5 The individual constituents of Comparative Example 5 were compounded using the previously described single stage twin-screw extrusion process.
  • the composition of Comparative Example 5 was tested for density, melt index (I 2 ) at a temperature of 190 °C and a load of 2.16 kg, and melt flow rate at a temperature of 230 °C and a load of 2.16 kg.
  • the results for the density, melt index (I 2 ), and melt flow rate for the composition of Comparative Example 5 are provided below in Table 2.
  • Comparative Example 6 Comparative Adhesive Composition Formulated with EVA and Styrenic Block Copolymer
  • Comparative Example 6 a comparative adhesive composition was produced using an ethylene- vinyl acetate copolymer (EVA) in place of the ethylene/a-olefin random copolymer of Example 1.
  • the composition of Comparative Example 6 included 20.0 wt.% EVA, 43.4 wt.% styrenic block copolymer, 30 wt.% tackifier, and 6.6 wt.% mineral oil.
  • the EVA was ELVAX® ethylene- vinyl acetate copolymer having 9 wt.% vinyl acetate.
  • the styrenic block copolymer, tackifier, and mineral oil were the same as described above for Example 1.
  • Comparative Example 6 The individual constituents of Comparative Example 6 were compounded using the previously described single stage twin-screw extrusion process.
  • the composition of Comparative Example 6 was tested for density, melt index (I 2 ) at a temperature of 190 °C and a load of 2.16 kg, and melt flow rate at a temperature of 230 °C and a load of 2.16 kg.
  • the results for the density, melt index (I 2 ), and melt flow rate for the composition of Comparative Example 6 are provided below in Table 2.
  • Example 7 Comparison of Properties of the Compositions of Example 1 and Comparative Examples 2-6
  • Table 2 which is provided below, includes the density, melt index (I 2 ), and melt flow rate for the composition of Example 1 and the adhesive compositions of Comparative Examples
  • Table 2 Properties of the composition of Example 1 compared to the properties of the adhesive compositions of Comparative Examples 2-4
  • Example 1 The composition of Example 1 and the adhesive compositions of Comparative Examples 2, 3, 5, and 6 were additionally tested using DSC to determine the melting curves of the compositions, from which the crystallization temperatures (Tc °C), melt temperature (Tm °C), glass transition temperature (Tg °C), heat of crystallization (AHc joules/gram (J/g)), and heat of melting (AHm J/g) for each composition, in accordance with the testing procedure previously described herein. These properties are provided below in Table 3.
  • Example 1 and the adhesive compositions of Comparative Examples 2, 3, 5, and 6 were additionally testing using DMS to determine the dynamic melt viscosity ( ⁇ * millipascal seconds (mPa-s)) at 150 °C, the ratio of the dynamic melt viscosity at 0.1 radians per second to the dynamic melt viscosity at 100 radians per second at a temperature of 150 °C ( ⁇ * ratio at 150 °C), and the storage modulus (G' @ 25 °C dyne/cm ) for each composition, according to the DMS testing procedure previously described herein.
  • the results of the DMS testing are provided below in Table 3.
  • the composition of Example 1 was tested two times, and the results reported in Table 3 below as Ex. 1-A and 1-B.
  • the composition of Examples 1-A and 1-B exhibited a lower crystallization temperature and melt temperature profile compared to the adhesive compositions of Comparative Examples 2, 3, 5, and 6.
  • lower crystallization and melting temperatures may reduce or prevent secondary crystallization of the constituents of the composition, which increases the cohesive strength of the composition. Increased cohesive strength may provide lower opening force for the composition and more tackiness, which increases the reclose force.
  • the lower crystallization and melting temperatures of the composition of Example 1 (Ex. 1-A, 1-B) may reduce or prevent secondary crystallization of the composition, thereby increasing the cohesive strength of the composition compared to the compositions of Comparative Examples 2, 3, 5, and 6.
  • the lower crystallization and melting temperatures of the composition of Example 1 enables the composition of Example 1 to exhibit a greater reclose force compared to the compositions of Comparative Examples 2, 3, 5, and 6.
  • the dynamic melt viscosity ratio ( ⁇ * ratio) at 150 °C for the composition of Examples 1-A and 1-B were less than the dynamic melt viscosity ratios of Comparative Examples 2, 3, 5, and 6.
  • a lower dynamic melt viscosity ratio translates to more consistent behavior in response to different shear rates, such as the different shear rates experienced by the film layer during film fabrication (e.g., blown film extrusion) or sealing conditions.
  • the compositions of Comparative Examples 2, 3, 5, and 6 have greater dynamic melt viscosity ratios, and therefore it is expected to be harder to maintain a stable bubble during blown film extrusion if shear rate changes.
  • the adhesive layer made from the compositions of Comparative Examples 2, 3, 5, and 6 could thin out to a greater extent with increases in sealing pressure, which would reduce the thickness of the adhesive layer and reduce the amount of adhesive composition to enable cohesive peeling through the adhesive and packaging resealing.
  • the composition of Examples 1-A and 1-B, which exhibited a reduced dynamic melt viscosity ratio of the compared to the compositions of Comparative Examples 2, 3, 5, and 6, is less sensitive to changes in shear rates, and therefore, the compositions of Examples 1-A and 1-B may be easier to process into the multilayer film and provide more consistent performance over a range of sealing temperatures and pressures compared to the compositions of Comparative Examples 2, 3, 5, and 6.
  • Example 8 Multilayer Films with the Compositions of Example 1 and Comparative Examples 2- 4
  • Example 8 each of the composition of Example 1 and adhesive compositions of Comparative Examples 2 and 3 were used to make a multilayer film to evaluate the reclose properties of the compositions.
  • the multilayer films were five-layer films made using blown film extrusion and included Layer A, Layer B, Layer C, Layer D, and Layer E.
  • Layer A was a seal layer comprising 98.4 wt.% DOW LDPE 5004i, 1.0 wt.% AMPACET 10063 antiblock masterbatch available from Ampacet Corporation, and 0.6 wt.% AMPACET 10090 slip masterbatch available from Ampacet Corporation.
  • Layer B included the composition of Example 1 or one of the adhesive compositions of Comparative Examples 2-4.
  • Layers C, D, and E all included identical layers of 100 wt.% DOWLEX 2038.68G LLDPE.
  • Table 4 The formulations for each multilayer film of Example 8 are provided below in Table 4.
  • Extruder 5 [0131] The multilayer films of Example 8 and shown in Tables 4 and 5 are of good integrity. These multilayer films of Example 8 are flexible films, formed from only coextrudable polymer formulations. These multilayer films can be used for packaging products, and can be processed on conventional film converting equipment.
  • Comparative film 8D was a commercially-available multilayer film believed to have been made by a blown film process at conditions typical in the blown film industry.
  • the film 8D included a pressure sensitive adhesive layer that was found to include primarily an SIS block copolymer.
  • the film 8D was found to not include a polyethylene copolymer of any kind.
  • Each of the multilayer film 8 A, and comparative films 8B, 8C, and 8D of Example 8 were adhesively laminated to a 48 gauge biaxially oriented polyethylene terephthalate (PET) (available from DuPont Teijin) using MORFREE 403A (solventless adhesive) and co-reactant C411 (solvent- less adhesive) both of which are available from the Dow Chemical Company, Midland MI, to form a final laminate film structure (sealant/PSA/core (3 layers)/solventless adhesive/PET).
  • the multilayer films of Example 8 were tested for initial peel strength and reclose peel strength according to the peel adhesion test previously described herein.
  • the reclose peel strength for each film was measured at time intervals after the initial opening peel strength.
  • the result for the initial peel strength and subsequent reclose peel strengths for each of film 8A, and comparative films 8B, 8C, and 8D are provided below in table 6.
  • the peel strength measurements are in units of newtons per inch (N/in) in Table 6 below.
  • film 8 A which included the composition of Example 1, exhibited an initial peel strength 34.7 N/in at a heat seal temperature of 130 °C. After being heat sealed at a temperature of 130 °C and initially opened, film 8 A exhibited a reclose peel adhesion of at least 2.5 N/in through four reclose cycles and a reclose peel adhesion of greater than 2.0 N/in after at least 7 reclose cycles. At a sealing temperature of 150 °C, the initial peel adhesion strength of film 8A was 40.5 N/in and the reclose peel adhesion strength was greater than 3 N/in after four reclose cycles and greater than 2.0 after at least 7 reclose cycles.
  • Comparative film 8D which was made with the adhesive composition of Comparative Example 4 that included mostly a styrene block copolymer, exhibited an initial peel strength 18.7 N/in at a heat seal temperature of 150 °C. After being heat sealed at a temperature of 150 °C and initially opened, comparative film 8D exhibited a reclose peel adhesion of less than 1.0 N/in through four reclose cycles and negligible reclose peel adhesion of less than 0.1 N/in after at least 7 reclose cycles.
  • initial peel strength of 40.5 N/in of the film 8A made with the composition of Example 1 was substantially higher than the initial peel strength of the comparative film 8D that included the styrene block copolymer pressure sensitive adhesive (PSA) of Comparative Example 4.
  • Film 8A also exhibited a substantially greater reclose peel strength after 4 cycles and 7 cycles compared to the comparative film 8D that included the styrene block copolymer PSA of Comparative Example 4.
  • Comparative film 8B included the adhesive composition of Comparative Example 2 for Layer B.
  • the adhesive composition of Comparative Example 2 included 43.4 wt.% of an ethylene/a-olefin block copolymer and 20 wt.% styrenic block copolymer.
  • the film 8 A included the composition of Example 1, which comprised 43.4 wt.% of the ethylene/a-olefin random copolymer.
  • the difference in composition between the composition of Example 1 and the adhesive composition of Comparative Example 2 is the substitution of the ethylene/a- olefin random copolymer in Example 1 for the ethylene/a-olefin block copolymer used in Comparative Example 2.
  • film 8 A which included the composition of Example 1
  • Comparative film 8B which included the adhesive composition of Comparative Example 2
  • film 8 A resulted in a lower initial peel strength compared to the initial peel strength of comparative film 8B.
  • the reclose peel strength of film 8 A after 4 cycles and after 7 cycles was comparable to the reclose peel strength of comparative film 8B that included the adhesive composition of Comparative Example 2.
  • the results measured after heat sealing at 150 °C exhibited a similar comparative relationship to the films prepared at a heat sealing temperature of 130 °C.
  • film 8A and comparative film 8B indicate that the film 8 A requires a lesser initial opening force compared to comparative film 8B, but would provide equivalent reclose performance. Therefore, film 8A would be easier to initially open compared to comparative film 8B, but would provide equivalent reclose strength to comparative film 8B.
  • Comparative film 8C included the adhesive composition of Comparative Example 3, which included only 33.4 wt.% of the ethylene/a-olefin block copolymer and 30 wt.% styrenic block copolymer.
  • Layer B of comparative film 8C had an increased proportion of styrenic block copolymer and decreased amount of ethylene/a-olefin block copolymer compared to Layer B of comparative film 8B and film 8A.
  • increasing the amount of the styrenic block copolymer in Layer B reduces the initial peel strength of the comparative film 8C compared to the initial peel strength of film 8A.
  • film 8A that included the composition of Example 1 in Layer B may provide better reclose performance compared to the comparative film 8C, which included an increased amount of styrenic block copolymer in Layer B.
  • Film 8A has a lesser amount of styrenic block copolymer in Layer B compared with comparative films 8C and 8D. Therefore, film 8A may provide reclose functionality to food packaging without impacting the odor and/or taste of the food products packaged therein.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wrappers (AREA)
  • Packages (AREA)
  • Bag Frames (AREA)
  • Cartons (AREA)
  • Closures For Containers (AREA)

Abstract

La présente invention concerne des emballages refermables, comprenant une paroi avant, une paroi arrière et une région de fermeture à proximité d'un bord extérieur d'un récipient à l'opposé d'un fond du récipient. La région de fermeture comporte une pluralité de régions d'étanchéité formant un joint d'étanchéité continu entre la paroi avant et la paroi arrière sur une largeur de l'emballage, et au moins l'une des régions d'étanchéité est non linéaire. La région de fermeture comporte en outre au moins une région non scellée délimitée entre les régions d'étanchéité. Dans certains emballages refermables, l'application d'une force d'ouverture à proximité de la région de fermeture permet de rompre le joint d'étanchéité continu entre la paroi avant et la paroi arrière sur une largeur de l'emballage. La géométrie de joint d'étanchéité peut être accordée en vue de régler l'amplitude de la force d'ouverture requise.
EP18793066.4A 2017-09-22 2018-09-20 Emballages refermables à géométrie de joint d'étanchéité accordable Withdrawn EP3694788A1 (fr)

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WO2019060531A1 (fr) 2019-03-28
TW201914925A (zh) 2019-04-16
US20200354112A1 (en) 2020-11-12
JP2020534220A (ja) 2020-11-26
BR112020005570A2 (pt) 2020-10-06
MX2020003154A (es) 2020-07-29
AR113126A1 (es) 2020-01-29

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