JP2006526552A - Plastic container with breakable seal - Google Patents

Abstract

The breakable seal includes first and second thermoplastic polymer layers and a third continuous polymer layer between the first and second polymer layers. The third polymer layer forms a first physical polymer blend with the first layer, and forms a second physical polymer blend with the second layer. The third layer can include a continuous fibrous strip of nonwoven polymer microfibers that melt in the sealing region. A method of manufacturing such a seal and a multi-compartment container including such a seal is disclosed. Food storage and cooking applications and various other end uses are disclosed.

Description

  This international application claims priority as a co-pending application of US patent application Ser. No. 10 / 455,055 “Nonwoven Plastic Pouch Separator” pending on June 5, 2003. In addition, US Provisional Application No. 60 / 511,064, filed Oct. 13, 2003, "Plastic Pouch With Ruptable Sealable Food Storage Storage and Preparation." ) ".

  The present invention relates to a plastic container, such as a pouch, that includes at least one breakable seal, often used to divide the container into a plurality of compartments. The present invention also relates to the application of such pouches to food storage and cooking, and other uses.

  Containers used to store materials that react when brought into contact with each other are known. Such containers include means such as, for example, sealed boundaries or barrier strips to prevent contact between the reactive materials until the reaction product is needed. Seals and barrier strips can separate containers, particularly plastic containers and packages, into a number of separate compartments from which various liquids or mobile reactive components can be isolated. Separating the barrier between the compartments provides a path for the reactive components to mix and react. The reaction may be facilitated by manual manipulation of the flexible package.

  Using multi-compartment plastic packages is known for containing reactive materials containing reactive liquid monomers that require separation from the activated material that converts the liquid monomer into a cured resin material. A typical combination of reactive components includes a liquid polysulfide polymer and a liquid epoxy monomer separated from a stable mixture of amine activators for the epoxy monomer. When mixed, these materials undergo an exothermic reaction to produce a heat-resistant and strong resinous product used as an insulating material.

  US Pat. No. 2,932,385 (Bollmeier et al.) Discloses a multi-compartment plastic package suitable as a container for holding a liquid epoxy monomer composition separated from a liquid polysulfide polymer. Has been. This package includes two sheets of thermoplastic film that are melt bonded along the outer edge of the film and separated into compartments by heat sealing the breaker strip between the films and extending to the melt edge of the film. A sheet is included. The breaker strip is physically weaker than the film and thereby breaks when stressed prior to the fracture of the melt end seal of the plastic package. US Pat. No. 3,074,544 (Bollmeier et al.) Describes several methods of forming multi-compartment packages using various sealing strips.

  Other references for multi-compartment plastic packages include, for example, U.S. Pat. Nos. 2,756,875 (Yochim), 2,916,197 (Detrie et al.). ), 3,809,224 (Greenwood), 4,961,495 (Yoshida et al.) And 5,287,961 (Herran). The '495 Yoshida reference discloses that the compartment can be filled with a medical pharmaceutical substance and mentions food. U.S. Pat. No. 2,971,850 (Barton) discloses other materials stored in multi-compartment plastic containers, and is a breakable membrane for separating the components of the enzyme system. A multi-compartment package is recognized. This package retains enzyme activity prior to membrane breakage and reaction between the enzyme and a suitable substrate material.

  However, there is a need for a breakable seal-forming material that reduces costs, improves consistency, and increases the efficiency of processes used to manufacture multi-compartment plastic storage bags and other containers with increased shelf life. Such seals are ideally suited for food storage and cooking applications and various other end uses.

  The present application describes a meltblown microfiber that can be mixed and / or interacted with pre-isolated contents in a separate compartment of a plastic container that has been separated by application of force and the seal has broken. An exemplary breakable strip seal is disclosed that includes microfibers such as The breakable seal may form a structure that temporarily isolates the contents of the container from the outside environment, or may include a partition to seal together plastic bags, pouches and similar container compartments. Multi-compartment plastic bags or pouches provide suitable containment of two or more materials that, when mixed and / or reacted by contact, provide useful products such as coating materials, encapsulating materials, bonding materials, and the like.

  The exemplary breakable seal is particularly suitable for food applications. Different food ingredients can be sealed in separate compartments of a multi-compartment plastic pouch that functions as a food storage article. In some cases, food filled pouches can be frozen for long-term storage until needed. To cook food for consumption, the pouch is placed in a microwave oven, the food ingredients are irradiated with microwaves, and cooked separately from each other for a first period. During the first period, the vapor pressure in at least one compartment (eg, due to steam) increases gradually to a level at which the breakable seal is broken, mixing different food ingredients present in the compartment near the break seal. Is made. The rupture of the seal is a sign of the end of the first period and the beginning of the second period during which different food ingredients can be cooked together in the pouch as microwaves continue to be irradiated. Turn off microwave irradiation at the appropriate time. This time is the end of the second period. The pouch can be opened by tearing, cutting or otherwise breaking the permanent seal around the pouch. In some cases, the pouch is heated using a method other than microwave cooking, such as a method that utilizes the sun or infrared, or a method that uses convection or heat conduction to place the pouch in boiling water or other heated fluid. be able to. In some cases, the pouch has an inflatable part that can collect the cooked food contents so that the user can ingest the cooked food contents directly from the open pouch with the pouch facing upwards on a flat surface. Can be included.

  In certain food or non-food applications, for example, for applications where heating is not desired, the pouch can be opened by hand manipulation such as squeezing or pulling. Yet another application may utilize a container that includes a molded plastic base and a thin plastic cover sheet sealed to a portion of the plastic base, forming an isolation compartment therebetween.

  An exemplary strip seal includes a substantially single material, such as a meltblown plastic microfiber layer. This is described in U.S. Pat. No. 2,932,385 (Bollmeier et al.), Which joins two films on the opposite side of a breaker strip consisting of a central fibrous section separating the outer film strips. This is different from the description of the breaker strip. The outer film strip includes the same thermoplastic polymer with two films bonded to either side of the breaker strip. This produces a film strip and film seal that is as strong as a seal formed by directly melt sealing one film to another. The fibrous central layer imparts a fragile surface to the breaker strip, which tears along the central surface as the film is pulled. When the breaker strip breaks, the two film strips remain attached to each other film, forming the side of the plastic package or container. According to the reference of '385 (Bollmeier et al.), Another example breaker strip consists of a thin porous paper coated on both sides with a thin continuous layer of polyethylene, Heat sealed to a polyethylene film that forms the outer envelope of the multi-compartment package. The center of the breaker strip paper remains porous and is prone to leakage due to premature rupture and separation due to chemical erosion. Either of these conditions creates an opening between the compartments. Premature rupture leads to undesirable leakage between compartments.

  As noted above, previously known seals are composites having fibrous portions sandwiched between successive layers of a barrier film of substantially the same chemical composition as the thermoplastic sheet film used to form the multi-compartment bag structure. Structure. The exemplary strip seal disclosed herein is a uniform structure formed by cutting a strip from a fibrous web, such as a web composed of meltblown microfibers. In some embodiments, these webs are characterized by an effective diameter of about 2.5 μm to about 7 μm. The effective fiber diameter (EFD) is further defined below, but in this application it is approximately close to the average fiber diameter but slightly larger. In certain embodiments, the web can include fibers having an actual diameter range (on average) of less than a micrometer to about 10 or 20 μm. One method of microfiber formation uses a known process that breaks the high-speed stream of thermoplastic polymer to produce small diameter fibers called meltblown microfibers.

  Exemplary bags, pouches or other containers can use a sheet of composite film laminate having a surface of polyethylene or other thermoplastic heat seal material proximate to the surface of polyethylene terephthalate ("PET") or other reinforcing material. . These sheets are oriented or arranged such that the heat seal material of each opposing sheet is inside the pouch and the reinforcing material is outside the pouch. The breakable strip seal used to separate two adjacent compartments of a plastic pouch can have fibers that have a higher melting point than the thermoplastic heat seal material inside the polymer sheet. In this case, when the heat seal temperature is lower than the melting point of the microfiber, the bond formation between the strip seal and the thermoplastic polymer sheet relies on a thermoplastic material that melts and flows into the gaps of the microfiber strip. A physical polymer blend of thermoplastic material is formed to produce a bonded structure. On the other hand, if the heat seal temperature is at or above the melting point of the microfiber, all or part of the microfiber strip seal will melt as the molten thermoplastic polymer sheet material flows into the gaps in the microfiber strip, again here. Form a physical polymer blend. In either case, a physical polymer blend of microfiber strip and thermoplastic material is produced on one side of the strip, and a physical polymer blend of microfiber strip and thermoplastic material is also produced on the opposite side of the strip. In either case, the original air in the microfiber strip gap is moved or otherwise moved substantially from the coupling area. An exemplary embodiment of a multi-compartment pouch or other container includes a polypropylene microfiber strip seal between polyethylene layers. Polyethylene wets polypropylene microfibers because there is no need to laminate a compatible film of polyethylene on either side of the polypropylene or add polyethylene fibers to the strip seal.

It is not necessary for the microfiber strip to melt during sealing, but in order to prevent migration of solids or liquids into the seal that will be the impermeable barrier, the seal containing the thermoplastic polymer microfiber is about It has sufficient burst strength of 0.1kg / cm ² (1.45psi) ~ about 1.25kg / cm ² (1.75psi). However, microfiber strip seals break due to moderate hand stress without damaging the thermoplastic sheet or breaking the end seal around the bag.

  The advantage of a meltblown polymer microfiber strip seal is a highly uniform inert material that provides a more reliable and consistent barrier strip seal than the aforementioned breaker strip, which includes a central layer of nonwoven or paper material. The manufacture of such a breaker strip includes at least one additional step of laminating the thermoplastic material on either the nonwoven or paper material before bonding the resulting breaker strip to the thermoplastic polymer sheet during package formation. A complex process is required. The additional processing steps increase the accuracy of inconsistent product performance, leading to waste and high manufacturing costs.

  Meltblown polypropylene microfiber webs are readily available materials that are obtained by a one-step process that is easier to control than the process used to produce a laminate of a polymer film and a nonwoven or paper material. In addition, single layer meltblown polymer microfiber webs with controlled levels of weighing, fiber diameter and porosity can be produced. Single layer strip seals do not have internal flat interfaces that fail due to, for example, premature rupture or separation after chemical erosion. When the sheet material is transparent, the strip seal formed from the meltblown polymer microfiber web is also a visual indication of effective barrier seal formation when the sealed joint changes from opaque to substantially transparent. This is advantageous. The transition from opaque to transparent creates a visible signal for the formation of a barrier seal that provides effective separation between sections of the plastic package.

  A multi-compartment plastic pouch or bag container can be manufactured to include two opposing sheets of a thermoplastic polymer film and at least one meltblown microfiber strip seal. By forming the melt end by heat-sealing the periphery of the end of the film sheet that forms the periphery of the bag, an airtight sealed internal space or skin is generated. A suitably disposed strip seal joined between two opposing sheets by applying heat and pressure, the interior space into first and second adjacent compartments disposed on opposite sides of the strip seal. Divide and form a barrier of material transfer between the first and second compartments.

  Further, the disclosed fibrous strip provides a seal that is ruptureable when sandwiched between heat and pressure between a first thermoplastic polymer layer having a first melting point and a second thermoplastic polymer having a second melting point. give. With the appropriate heat and pressure, material from the first thermoplastic polymer layer flows at least partially to one side of the fibrous strip and proceeds to the gap between the individual fibers of the strip. Similarly, material from the second thermoplastic polymer layer preferably flows at least partially to the opposite side of the fibrous strip and also into the gaps between the individual fibers. This can occur when the melting point of the fibers in the fibrous strip is higher than the first and second thermoplastic polymer materials. An exemplary breakable seal is formed when the first and second thermoplastic polymer materials contact each other through the thickness of the fibrous strip to form a physical polymer blend. Depending on the bonding conditions, the portions of the fibrous strip in the sealing area still contain individual identifiable microfibers or are melted. The presence of individual fibers (or molten fibers) creates a bond or seal that is weaker than a direct seal between the first and second thermoplastic polymer layers. In this way, the applied force tears the seal along the embedded fibrous strip and provides a controlled release along the length of the breakable seal.

  In certain embodiments, the first thermoplastic material flowing to the first major surface of the fibrous strip is considered to form a first boundary layer bonded to the first polymer layer and the fibrous strip. The second thermoplastic material flowing to the second major surface is believed to form a second boundary layer bonded to the second polymer layer. The melting point of the fibers making up the sealing interlayer may be higher than the melting points of the first and second thermoplastic materials and may include a plurality of microfibers having an average effective fiber diameter of about 2.5 μm to about 7 μm. The first boundary layer includes a first portion of a plurality of microfibers surrounded by a first polymer material. The second boundary layer includes a second portion of a plurality of microfibers surrounded by a second polymeric material. The breakable seal can have a frangible interface between the first boundary layer and the second boundary layer. The breakable seal is split at the fragile interface by applying force to separate the first boundary layer from the second boundary layer.

  These and other aspects of the invention will be apparent from the detailed description below. However, the above summary should not be construed as limited to the claimed subject matter, which is defined solely by the appended claims that would be amended during the performance of the procedure.

  Throughout the specification, reference is made to the accompanying drawings, wherein like elements are designated with like reference numerals.

Glossary As used herein, the following terms have the following meanings unless otherwise specified.

  “Microfiber” refers to a fiber having an average diameter of about 20 μm or less, preferably from about 1 μm to about 10 μm.

  “Effective fiber diameter” is a calculated dimension derived from the pressure drop of a known thickness, polymer density and weighed microfiber web known to those skilled in the art.

  “Breakable seal”, “barrier seal” and the like refer to a hermetic seal formed using at least one plastic sheet that allows the closure to be opened without tearing the plastic sheet. In some cases, such seals inject the molten thermoplastic polymer into the space between the microfibers forming the sides of the strip seal and at least two layers of thermoplastic polymer bonded to the sides of the strip seal. And a composite layer including the boundary layer generated by.

  “Strip seal”, “separator strip seal”, “microfibrous strip seal”, “sealing interlayer”, “fibrous strip”, etc. refers to a collection of fibers formed into a long and thin porous layer. , And may optionally include a blown microfiber web that has been converted to a strip form that is used to form a breakable seal between suitable layers of a polymer film or film laminate. This definition also includes strip seals (etc.) embedded between thermoplastic material layers, and the fibers of such strip seals can be partially or fully melted to form physical blends with other polymers, Form shapes other than fibers.

  A “boundary layer” is formed on either side of the barrier seal when molten polymer is injected into the strip seal to provide a polymer-filled side portion of the strip seal upon cooling.

  The “easy to break interface” refers to the central portion of the seal that can be broken. In some cases, the easily breakable interface may be between the boundary layers and may include microfibers that are substantially free of thermoplastic polymer. This provides a relatively fragile interface that is preferentially divided during forced separation of opposing boundary layers. In some cases, the frangible interface can include a portion where the first polymer contacts the second polymer. In some cases, depending on the bonding temperature and pressure dwell time, the molten polymer can substantially fill the interior space of the strip seal. The main portion of the fragile interface may optionally include a microfiber-containing gap between the boundary layers.

  A multi-compartment plastic pouch or bag container as shown at 10 in FIGS. 1 and 2 comprises two opposing sheets 12, 14 of a thermoplastic polymer film and at least one meltblown microfiber strip seal 16 or similar fibrous strip. Can be manufactured to include. Depending on the duration and pressure required for bonding, the polyethylene (or other suitable thermoplastic) layer is melted at a temperature of about 120 ° C. to about 200 ° C. to provide a molten permanent heat seal margin 18a around the edge of the film sheet, 18b and 18c are formed, and an airtight sealed internal space or skin is generated. In FIGS. 1 and 2, such a space is created after formation of the final end seal at the top of the pouch facing the margin 18b. A suitably arranged strip seal 16 bonded between the two film sheets 12, 14 divides the interior space into first and second adjacent compartments 20, 22, respectively, from the first compartment to the second compartment. It becomes a barrier of material transfer to The bonded strip seal 16 forms a breakable barrier seal 16a along the strip seal and has a narrower width than the strip seal itself, as indicated by the dashed line extending along the strip seal 16 of FIG. It is preferable to have. The breakable barrier seal 16a is not retained in a portion that overlaps a heat-sealed margin such as 18b, and if a break occurs at the barrier seal 16a, the peripheral edge seal remains intact and the internal space of the pouch is closed. Note that it will remain. The size and location of the two compartments depends on the location of the strip seal inside the plastic package. Additional strip seals can be placed between the two film sheets to increase the number of compartments in the bag container.

  The overlap region (15 in FIG. 1) of the end of the strip seal 16 where the permanent end seal such as 18b intersects the strip seal is for mechanical reinforcement by being located at the opposite end by the permanent end seal 18b. The presence of the embedded fibrous strip or strip seal 16 forms a seal that is not as weak as the central portion of the barrier seal 16a, but is not as strong as the permanent heat seal margins 18a, 18b, 18c. Such an intermediate strength seal in region 15 can be advantageously used as a pressure relief mechanism. Thus, for example, after the compartments 20, 22 are closed with permanent upper end seals, a first amount of pressure is applied to break the barrier seal 16a. When more pressure is applied (or the pouch temperature is increased), the area 15 and its counterpart on the top of the pouch 10 are relatively small, but provide the expected break point, and the seat 12, 14 or permanent end seals. Through one, the pouch becomes stronger and less predictable. The strength of the overlapping region 15 can be adjusted by changing the sealing conditions (temperature, pressure, downtime, etc.) of the permanent heat seal margin 18b. Prior to sealing the upper and lower end seals, and prior to aligning the narrow or wide portion with the upper and lower ends of the pouch 10, a portion of the fibrous strip or strip seal 16 may be selectively narrowed or widened. It can also be adjusted by doing. This is illustrated in the partial views of FIGS. 1a and 1b, which generate modified overlap regions 15a and 15b, respectively.

  FIG. 1c shows another partial view of a part of the lower permanent end seal 19 formed, for example, by heat sealing a film sheet such as 12 or 14 described above. The end seal may be part of the container embodiment described herein, or may be part of a conventional multi-compartment pouch or other container, or even a conventional single-compartment pouch or container. However, what is included in the seal is a fibrous strip that is large enough to widen the end seal and preferably, but not necessarily, extends slightly beyond the seal into the sealed compartment 21. Or 17 strip seals. The sealed strips are located at opposite ends by a strong permanent seal, but can be broken. The strip seal 17 can thus provide a simple low-cost pressure relief mechanism for virtually any type of plastic container.

  Suitable film materials for multi-compartment plastic packages are selected from the group of film composites comprising polymer films and suitable heat seal layers. Various thermoplastic polymers may be used to form the barrier seal to provide a bonding layer that melts below or near the melting point of the microfibrous strip seal. Suitable materials include, for example, polyolefin polymers such as polyethylene and polypropylene, polyvinyl chloride, and ethylene vinyl acetate, and further polyethylene terephthalate (PET) that melts at higher temperatures than those used during the bonding process. Selected from film composites comprising these materials laminated with a film of polymer capable of providing the desired strength. The reinforcing layer such as PET preferably forms the outer layer or the exterior of the pouch or other container, and is preferably composed of a material having a higher melting point than the thermoplastic material forming the interior of the pouch or container. Alternatively, the reinforcing layer can comprise or consist essentially of metal foil such as, for example, polypropylene, nylon (polyamide), polyethylene naphthalate and other polyesters, fluoropolymers and aluminum foil.

  The production of blown microfiber polymer webs relies on a type of process described by Van Wente in Industrial and Engineering Chemistry Vol. 48, No. 8, 1956, p. Is preferred. US Pat. No. 3,978,185 (Buntin et al.) Is similar but reduces the amount of undesirable coarse “shots” and “beads” of material larger than about 0.3 mm in diameter. Improved methods are described. According to this manufacturing method, various thermoplastic materials including nylon (polyamide), polyolefin, polystyrene, poly (methyl methacrylate), poly (ethylene terephthalate) and polytrifluorochloroethylene are 0.1 μm to 1.0 μm. It is shown that fine microfibers can be obtained. Fiber formation requires the use of an apparatus that is essentially a ram extruder that presses the molten material directly through two rows of narrow orifices into two converging high speed streams of heated air or other suitable gas. The air temperature and polymer melt temperature are adjusted separately as well as the velocity of the air and thermoplastic fluid material streams.

  Resin released from the extruder nozzle at a temperature of about 290 ° C. (550 ° F.) to 430 ° C. (800 ° F.) enters the gas stream as a molten strand of resin, and the gas stream attenuates the fibers. The fiber is formed at a certain point in the gas stream, and the cooling sufficiently proceeds to solidify the resin material. The hot melt resin exits the nozzle and directly enters the two combined air streams so that the maximum amount of attenuation occurs at this point at the outlet. Depending on the exact temperature and speed used, the fiber is cooled to solid form after being carried by the air stream at a distance of about 2.5 cm from the nozzle tip.

The newly formed fiber moves away from the nozzle in a high speed, dispersed turbulent stream. At typical air conditions of about 315 ° C. (600 ° F.) and about 3.5 kg / cm ² (50 psi), this speed is equal to or greater than the speed of sound, ie, about 500 meters per second (1 second). 1600 feet). A movable 16 mesh screen is stripped from the screen as a (non-woven) fiber mat that is collected on a take-up reel with or without the air blast separated from the fiber and densified with a press roll. Provides a surface that gives irregularly attached fibers. The effective fiber diameter (EFD) of the meltblown polymer web, preferably polypropylene web, suitable for the manufacture of the strip seals described herein is preferably about 1-20 μm, preferably 2.5 μm-7 μm, more preferably 4 μm- 6 μm. Polymer webs or fibrous strips composed of microfiber assemblies in a nonwoven layer have been found to be useful for the disclosed applications, and the average (actual) diameter of the fibers in some embodiments is about 4 μm to In other embodiments, it is about 12 μm. An exemplary range of average fiber diameter is considered to be about 1-20 μm, more preferably about 4-6 μm.

  In the original state prior to sealing, the strip seal or fibrous strip is preferably both (1) continuous and (2) porous. This is (1) substantially free of through-openings in the strip and (2) porous due to the interconnect gap space between the fibers. The continuous feature prevents or prevents the softened thermoplastic sheet material from flowing in a direct path across the strip, forming an unblocked island of thermoplastic material and reducing the desired breakability of the seal. However, due to the porous feature, the softened thermoplastic sheet material forms a bent or serpentine path to at least the outer part of the strip seal, and the strip thickness does not melt if the microfibers of the strip do not melt during sealing. Preferably. After sealing, the portion of the strip seal or fibrous strip that extends out of the sealing area remains substantially continuous and porous, as not all heat and pressure is applied in the sealing area. The portion of the strip within the sealing zone remains substantially continuous, and the physical polymer blend (ie, interconnect material structure) along with the adjacent thermoplastic layer, whether the microfiber remains intact or melts during the sealing process. ).

  A preferred combination of microfiber and thermoplastic sheet material is such that when placed in melt contact with each other, they do not join significantly to each other. This prevents the formation of an excessively strong seal bond if both the thermoplastic sheet material and the microfibers in the fibrous strip melt due to bonding conditions. Preferred combinations of microfiber / thermoplastic materials include, but are not limited to, polypropylene / polyethylene, nylon / polyethylene, PET / polyethylene, fluoropolymer / polyethylene, fluoropolymer / polypropylene, nylon / polypropylene and PET / polypropylene. In each combination, the first material refers to the composition of microfibers and the second material refers to the composition of the thermoplastic material layer bonded to the fibrous strip.

  A convenient package for reactive materials, particularly fluid materials and food ingredients, which are stored separately, includes at least two sheets of thermoplastic polymer film bonded to each other along the perimeter. In the present specification, “two sheets” or the like can refer to a single sheet folded on itself. The separation of the two components is done by one or more breakable seals, also referred to herein as strip seals that form a barrier of material transfer between the isolation compartments in the package. The material of the strip seal (ie, the individual fibers that make up the strip seal) generally has a melting point that is close to or higher than the internal thermoplastic film layer used to form the package. By controlled heating of the thermoplastic film layer to the strip seal disclosed herein, the microfiber strip seal at a temperature above the melting point of the thermoplastic film layer but close to or below the melting point of the microfiber seal material. The film layer melt-flows at least initially to the sides. The microfiber strip seal may or may not melt itself depending on the sealing conditions. Upon cooling, the thermoplastic film layer bonds to the microfiber strip seal to provide a breakable seal.

  A breakable seal formed by bonding the plastic film described above to a microfiber strip seal is a pouch, shell or other container material in a nearby compartment during normal handling, shipping and storage operations. It is strong enough to completely separate from a material. The disclosed multi-compartment plastic pouch can maintain multiple seals in a two-component container or in a bag with three or more compartments until needed to mix the separated materials . In some cases, it may be appropriate to start the mixing process by grasping a portion of the film on the opposite side of the strip seal and pulling the film in the opposite direction to break the seal and move the material through the open seal It is. Thorough mixing of the materials can be done by manual manipulation of the flexible plastic package. In other cases it may be appropriate to apply pressure by squeezing one or more compartments to break the seal. Alternatively, the vapor pressure generated within one or both adjacent compartments, such as heating with microwave radiation or other suitable energy form, can be used to break the breakable seal without having to touch the package. . The fluid flow along with the foaming action as occurs during cooking is sufficient to properly mix the materials after breaking the seal between the compartments. From the continuous description of the operation for mixing the separated materials inside the bag container, it is clear that the (permanent) end seal between the sheets of thermoplastic film is stronger than the breakable seal.

  The formation of a heat seal between a portion of a thermoplastic film sheet and a strip seal involves a series of process steps that involve inserting a strip of microfiber web between two sheets of film. This creates a sandwich structure with a narrow strip of microfibers extending between two sheets of film. Each sheet is wider than the microfiber strip, with the end of the sheet overlapping the end of the seal-forming microfiber strip. After the film sheet is bonded to the microfiber strip, a sandwich structure is placed between a pair of heated platens. One or both platens can include separately controlled heating rails aligned with the strip seals, and if desired, the heating rails beyond the width along the parallel edges of the sheet sandwich. Can be included. The rails can be made of metal to have good thermal conductivity, and heat stable like fluoropolymers and silicone rubbers to more evenly distribute the applied pressure within the desired sealing area or zone It may also include an outer layer or cover ring of compatible cushioning material. The location and number of heating rails will vary depending on the specific design of the multi-compartment packaging container or pouch. After closing the heated platen around the sheet structure, application of pressure causes the film layer to bond to the strip seal and melt beyond the width of the sheet along the edge of the sheet. A flat pressure printer produces a bag or pouch having at least one barrier seal that seals along parallel edges and its base and separates a number of compartments. The multi-compartment bag described above has an opening for each compartment for the addition of materials for which temporary separation is desirable. In FIG. 1, the openings of compartments 20 and 22 are shown as 24 and 26, respectively. After the material is placed in each compartment, the open end of the multi-compartment package may be sealed using a second flat pressure printer that includes a heated rail to form a final end seal. The temperature of the end seal formation may be high enough to produce a melted joint at the intersection between the end seal and the strip seal. This type of fusion bond formation provides advantages over known breaker seals that include paper texture. A joint containing a paper strip provides a break point at the temperature at which the paper is scorched.

  In one embodiment, a flat press temperature generally in the range of about 140 ° C to about 150 ° C is used. This temperature range is higher than the melting point of the thermoplastic heat seal layer in contact with the strip seal, but lower than the melting point of the meltblown microfiber strip seal itself. The heating time is generally 2 to 4 seconds depending on the pressure applied to the platen of the flat pressure printing press. By application of suitable heat and pressure, the thermoplastic layer melts, the molten polymer moves to the intersection of the microfibers, and a boundary layer containing a molten polymer that solidifies upon cooling is created on both sides of the seal strip. The thermoplastic polymer flowing from one side of the strip seal contacts the polymer flowing from the opposite side. Efficient bonding between the strip seal and the package film leaves at least the inner part of the strip seal free of thermoplastic polymer and breaks the breakable strip while applying force to the plastic package. Is provided to separate the boundary layer of the strip seal.

  In the preferred embodiment, upper and lower active heated metal rails are used corresponding to breakable bonds. The rail does not have a buffered heat stable material and is heated to a temperature in the range of about 270-310 ° F. This temperature range is sufficient to immediately melt the thermoplastic heat seal layer in contact with the strip seal. The heating time for heating the upper and lower elements is generally 0.5 to 2 seconds. By suitable application of pressure, the melting of the thermoplastic layer and the movement of the molten polymer to the intersection of the sealing intermediate layer first occur. As the sealing cycle continues, the molten thermoplastic material penetrates the fibrous strip or strip seal and contacts each other within the strip seal. In other cases, the molten thermoplastic material penetrates the strip seal, melting its individual microfibers, resulting in a completely molten physical polymer blend, forming a breakable seal. In both cases above, the breachable seal contains polymer material (including polymer material from the inner thermoplastic sheet layer and microfiber) throughout its thickness, and the heat seal area is substantially air-containing. Absent. This process may be performed in a batch mode to form a single breakable seal or a step-and-repeat process that forms a continuous breakable seal used in a continuous container making process.

  A deformation process that forms a heat seal between a portion of a thermoplastic film sheet and a strip seal includes a series of continuous process steps including inserting a strip of meltblown microfiber web between the two sheets of film. It is. This creates a sandwich structure with a narrow strip of microfibers extending between two sheets of film. Each sheet is wider than the microfiber strip, with the end of the sheet overlapping the end of the seal-forming microfiber strip. The film sheet is aligned along the strip seal and bonds to the microfiber strip during the sandwich movement between rollers heated to high temperatures. The duration of contact between the thermoplastic film sheet and the heated roller causes the thermoplastic layer to melt at least enough to produce a boundary layer on either side of the seal strip that contains a molten polymer that solidifies upon cooling. Moves to the intersection of the microfibers. The thermoplastic boundary layers are preferably in contact with one another, and the microfiber layer may or may not be wholly or partially melted in the area of the seal.

  Other means of heating the sealing area of the disclosed breakable seal (or permanent seal) include the use of ultrasonic horns, electromagnetic induction heating and radio frequency heating.

  The continuous sandwich structure formed as described above enters another heat sealing device that creates a perimeter seal by applying heat and pressure along the edges of the overlapping sheets, optionally beyond the sheet structure, For example, a plastic package having two compartments separated by a strip seal as shown in FIGS. 1 and 2 is provided. One end of each compartment remains open for filling with temporarily isolated reactive material, food material or other desired material, then the compartments are closed and the materials are isolated from each other until the breakable seal is broken A heat sealer forms a final melt end seal.

  In the process of forming breachable seals and containers with these seals, individual portions of the seal area may be contacted multiple times by a heated sealing bar. Heating may occur from one side or both sides, or may be done in a manner that heats alternate sides of the seal in a separate contact step, such as a step-and-repeat process similar to that described above. In some cases, container formation, container filling and container final sealing can be performed in a single continuous process, commonly known as forming, filling, and sealing.

  The meltblown microfiber web used to form the preferred strip seal includes a non-woven, fibrous polymer material, preferably a polypropylene homopolymer such as No. 3960 at 230 ° C melt flow rate of about 280-420 g / 10th. Polymers (available from Atofina, Houston, TX). Microfiber webs typically have from about 10 grams per square meter (gsm) to about 30 gsm when using opposing sheet materials each having a thermoplastic heat seal (inner) layer thickness of about 3.5 mils, Preferably it has a basis weight of about 25 gsm. The ideal basis weight for a given application will depend on the thickness of the thermoplastic polymer material that forms the inner layer of the container, the lower the basis weight, the better for the thinner thermoplastic layer. The reverse is also true. Preferred effective fiber diameters and actual fiber diameters are as described above. Such strip seals result in less bumps between the packaging film and other seals, such as end seals. A strip seal having a width of about 1 cm to 1.25 cm and a basis weight of 15 gsm has a thickness before sealing of about 100 μm and a thickness after sealing of about 25 μm (0.001 inch).

  Preferred nonwoven microfiber web materials can be compressed by more than one half in the area of the seal. This outline is shown in FIG. Opposing heat-seal rails 40, 42 are pressed against sheets 44, 46 and strip seals or fibrous strips 48 (shown schematically in each figure) in sealing region 50 to break as described in this application. Form a possible seal. Sheets 44 and 46 preferably include inner thermoplastic layers 44b and 46b and outer reinforcing layers 44a and 46a, respectively. When the heat seal rail applies heat and pressure to the structure, the fibrous strip 48, preferably non-woven microfibers, is compressed in the sealing region 50. If the molten thermoplastic polymer from the inner layers 44b, 46b moves to the opposite fibrous strip and the temperature is low enough that the strip 48 does not melt, the thermoplastic materials are preferably in contact with each other as shown. A surface layer is formed in the strip to be formed. The strip 48 is preferably larger in size than the sealing area 50 so that the end portion 48a of the strip extends away from the breakable seal and extends into the defined compartment 52. A large or stretched fibrous strip that exceeds this sealing area advantageously provides normal manufacturing tolerances in the placement of the fibrous strip relative to the heat seal rail. Unlike the central portion of the strip 48 in the sealing region 50, the end portion 48a of the strip is not in intimate contact with the thermoplastic layers 44b, 46b. Whether or not the fibrous strip 48 is melted in the sealing region 50 during sealing, the observed thickness t2 of the (melted or intact) fibrous strip in the sealing region is generally the end portion 48a. Typically, the relative thickness ratio is about 2-4, substantially less than the observed thickness.

  If at least one (preferably both) of the sheets 44, 46 is substantially transparent so that the contents in the compartment are visible to the user, the strip seal formed from the polymeric microfiber nonwoven web is It is also advantageous as a visual indication of effective barrier seal formation when the sealed joint changes from opaque to substantially transparent. Fibrous strips or strip seals tend to be opaque and generally have a white appearance before sealing. This appearance is largely due to the high scattering properties of many reflective surfaces formed by individual microfibers when surrounded by air. This appearance changes to substantially transparent when the fibrous strip forms a normal breakable seal against the transparent sheet. This is because the thermoplastic material of the sheet substantially replaces the air in the sealing area so that the fibers (or molten fiber shape) of the fibrous strip are surrounded by the thermoplastic material. The refractive index of thermoplastics is very close to that of microfibers, so reflections on the surface of the microfibers are greatly reduced, light scattering by the fibrous strip is reduced, and a physical polymer blend of microfiber / thermoplastic material Light can more easily pass through the characteristic sealing area 50. As a result, the closer the refractive index of the microfiber is to that of the thermoplastic material, the more transparent the sealing region 50 becomes. The transition from opaque to transparent creates a visible signal for the formation of a breakable seal that provides effective separation between the sections of the plastic package. The sealing operation is to remove the appearance of the structure from a completely opaque (generally white) strip to at least one, usually two opaque regions (of the strip 16 other than the end portion 48a in FIG. 3 and the seal 16a in FIG. 1). To a substantially clear central region (corresponding to region 50 in FIG. 3 and barrier seal 16a in FIG. 1).

The porosity of meltblown microfiber webs varies depending on the weight and fiber diameter. These features control the flow rate of the molten polymer to the intersection between the microfibers during the bonding process to either side of the packaging film sheet microfiber strip seal. After the heat-sealed container bag is normally formed, the strength of the breakable barrier seal is evaluated using a pressure bag breaker. This test involves expanding the adjacent section on the opposite side of the strip seal to an air pressure at which the meltblown microfiber seal ruptures. A preferred range of seal strength is about 0.21kg / cm ² (3psi) ~ about 0.63kg / cm ² (9psi).

  The strength of individual breakable seals can also be assessed by conventional peel tests such as ASTM F88-00 (standard test method for seal strength of flexible barrier materials) or variations of this test. These test methods are particularly useful when only the breakable seal itself can be used for testing, not the pouch or the entire container.

  Suitable packaging polymer sheets for forming the disclosed bags and pouches include polymer films having a lower melting point than the polymer used to form the meltblown microfiber web. As a preferred example, the multi-compartment bag is also available under the trade name (SCOTCHPAK) 29905, available from 3M Company, St. Paul, Minn. A known film laminate). The film laminate consists essentially of a 86 μm (3.4 mil) thick layer of linear low density polyethylene adjacent to a 14 μm (0.56 mil) thick layer of biaxially oriented polyethylene terephthalate. During the formation of a multi-compartment pouch, the SCOTCHPAK 29905 film is constructed so that the polyethylene layers of both sheets become an inner layer that bonds to the strip seal and forms a barrier seal during heating at about 120 ° C to about 200 ° C. Arrange opposing sheets.

  Various fluid components may be sealed in separate compartments of a multi-compartment package. A typical combination of reactive components for non-food applications includes a liquid polyol resin as the first material and an isocyanate crosslinker as the second material. These materials are reacted to form polyurethane capsules or block compounds. The second combination of reactive components includes a liquid having anhydride functionality and a suitable crosslinker. These two components are reacted to give a polyester encapsulant material. The component materials that react to form the epoxy resin may be stored in a multi-compartment package. In this case, the package separates the liquid epoxy-functional composition from the liquid polymer and amine activator mixture prior to formation of the epoxy resin. To effect the reaction between the resin-forming components, the outer package film is gripped near the central region of one compartment and the film is pulled along the axis of the breakable seal. This breaks the strip seal by fiber separation at the fragile interface between the strip seal boundary layers without damaging the permanent melt end seal of the package. The rupture of the fragile interface mixes the reactive contents of the package. Uniform confusion requires manual manipulation of the package skin to promote the resin formation reaction. Removal of the package corners provides an opening for discharge of the reaction mixture that is dispensed into a stand-by mold or other cavity or vessel where the reaction persists until completion. Instead of removing the corners from the multi-compartment package, a nozzle plug may be incorporated into one of the film sheets to produce the package.

  Additional non-food applications of the disclosed multi-compartment package include flexibility for reacting materials to produce resins for various end uses such as resins for telecommunications systems, particularly encapsulant materials. The use as a container bag is mentioned. According to the chemical resistance test of meltblown microfiber strip seals with different encapsulating resin systems, the multi-compartment package supporting a weight of 1 kg, to the seal during oven aging at a high temperature of 65.5 ° C. (150 ° F.) No damage was shown.

  As mentioned above, the preferred breakable seal disclosed herein is particularly suitable for food applications. Different food ingredients can be sealed in separate compartments of a multi-compartment plastic pouch that functions as a food storage article. In this case, the choice of strip seal and sheet material can be conveniently selected from a number of known polymeric materials that are acceptable for conventional food packaging applications. In some cases, food filled pouches can be frozen for long-term storage until needed. To cook food for consumption, the pouch is placed in a microwave oven, the food ingredients are irradiated with microwaves, and cooked separately from each other for a first period. During the first period, the vapor pressure in at least one compartment (eg, due to steam) increases gradually to a level at which the breakable seal breaks, resulting in different food ingredients present in the compartment near the broken seal. Is mixed. The rupture of the seal is a sign of the end of the first period and the beginning of the second period during which different food ingredients can be cooked together in the pouch as microwaves continue to be irradiated. Turn off microwave irradiation at the appropriate time. This time is the end of the second period. The pouch can be opened by tearing, cutting or otherwise breaking the permanent seal around the pouch. In some cases, the pouch may be heated using a method other than microwave cooking, such as a method that utilizes the sun or infrared, or a method that uses convection or heat conduction to place the pouch in boiling water or other heated fluid. it can. In some cases, the pouch has an inflatable part that can collect the cooked food contents so that the user can ingest the cooked food contents directly from the open pouch with the pouch facing upwards on a flat surface. Can be included.

  In particular, FIG. 4 shows a pouch 30 similar to pouch 10 except that it includes an inflatable gusset portion. For ease of explanation, components that correspond substantially in structure and function to the components of FIGS. 1-2 have been given the same reference numerals with the addition of prime symbols. A pouch 30 is shown before filling the compartments 20 ', 22' with food or other contents and before the final end seal operation to close the openings 24 ', 26'. Unlike the pouch 10 of FIG. 1, which uses a substantially flat sheet, the pouch 30 incorporates folds 32, 34 into one of the compartments 22 ', one or both opposing sheets 12', 14 '. . The folds expand the compartment 22 'to receive the bulk of the combined contents of the compartments 20' and 22 'and form a stable base at one end of the pouch when the pouch is full. In order to maintain a good seal, it is preferred that the strip seal 16 'and thus the barrier seal 16a' also not intersect the fold.

  FIG. 5 shows the multi-compartment pouch 60 in a plan view. Pouch 60 includes a plurality of fibrous strips arranged to form a plurality of compartments isolated in a single pouch. The two film sheets 62, 64 are a breakable seal 66a, 68a, 70a, 72a (formed along the fibrous strips 66, 68, 70, 72 respectively) and heat sealing or other conventional means Are connected through permanent seals 74a-d formed by These seals form isolation compartments 76, 78, 80, 82, 84 and, as can be seen in the drawings, the pair can be fluidly bonded by breaking selected breakable seals. Filling the compartments with the desired contents can be done prior to completing one or more permanent seals, by direct injection into the compartments after pouch formation, or a combination thereof. Overlapping regions 86a-h can be formed as shown to function as a pressure relief mechanism. Note that the fibrous strips 66, 68, 70, 72 may or may not have the same structure. If not the same, strips with different basis weights, fiber diameters, etc. can be selected to provide a breakable seal with the desired set of predetermined seal strengths. Any infusion or dispenser nozzle, dip tube or other device shown at 88 can be provided in compartment 78 and similar devices can be provided in other compartments. Alternatively, compartment 78 may remain free of contents in some embodiments, but breaks other breakable seals and removes the pre-separated contents of compartments 76, 80, 82, and 84. Only after thorough mixing can the puncture seal 68a function as a final dispensing chamber or outlet.

  FIG. 6 is a plan view showing another multi-compartment pouch 90. The pouch 90 is similar in many respects to the pouch 60 except that the two pouches 90 are arranged so that the two fibrous strips cross each other. The two film sheets 92, 94 are permanent seals formed by mesh and heat sealing of crossed breakable seals 96a, 98a (formed along the fibrous strips 96, 98, respectively) or other conventional means. 100a-d. These seals form the isolation compartments 102, 104, 106, 108 and can be fluidly coupled in pairs by breaking selected breakable seals. Compartment filling can be performed as described above. Overlapping regions 110a-d are formed as shown.

  FIG. 7 shows a plan view of a multi-compartment pouch 120 that includes a series of combinations of two breakable seals and one permanent seal that separates the two compartments to provide unique mixing capabilities. In the pouch 120, the opposing thermoplastic sheet includes a net of breachable seals 122a, 124a (formed along the fibrous strips 122, 124, respectively), a permanent seal 124a-d along the perimeter of the pouch, and a breakable. These are joined through a permanent seal 124e connecting the various seals, and compartments 126 and 128 are formed. Selectively break one of the seals that can be broken (eg, by applying stabilizing pressure to the upper seal 122a, the lower seal 124a with one hand, and squeezing one of the compartments with the other hand), and the other Fluid communication is made between the compartments by breaking the breakable seals (e.g., by manually applying a stabilizing pressure to the upper seal 122a while squeezing one of the compartments 124a). By alternately pinching one of the open breakable seals and the other, or substantially closing the other, true circulation of the combined fluid material is made between the chambers.

  In the embodiment of FIG. 7, two separate relatively short fibrous strips need to be placed and aligned. In an alternative embodiment, a single long fibrous strip can be used as shown in FIGS. 7a and 7b. In FIG. 7a, the fibrous strip 140 has a central narrowed portion 140a. To form a seal between the compartments, a straight sheet seal bar with a (uniform) width between the end of the strip 140 and the central portion 140a is used. In this way, the fibrous strip is sized larger at the end than the sealing area (vertical dashed line), forming a breakable seal. However, in the central portion of the portion 140a, the fibrous strip is smaller in size than the sealing area and a permanent seal is formed by direct contact of the upper and lower sheets of thermoplastic sheet material on at least one side of the strip portion 140a. In FIG. 7b, the width of the fibrous strip 144 is uniform, but creating a non-uniform sealing area 146 using a non-uniform width heat seal bar connected to a breakable seal at both ends of the permanent seal. A central permanent seal is also obtained.

  FIG. 8 shows a schematic cross-sectional view of the multi-compartment container 150. The container 150 is similar to other disclosed embodiments except that the flexible flexible plastic sheet is a relatively rigid molded plastic base 152. Cover sheet 154 may be selectively bonded to base 152 by seals 156a, 156b, 156c, one or all of which may be a breakable seal formed of the disclosed fibrous strip.

  FIG. 9 shows a single compartment pouch 160 in plan view. A breakable seal 162a is provided along one end and a permanent seal 164a-c is provided along the other end. Similar to the embodiment described above, the width of the fibrous strip 162 is increased so that a portion of the strip extends beyond the sealing area corresponding to 162a. The breakable seal 162a provides a convenient opener and the contents of the compartment 166 are made available to the user.

Applications Containers incorporating the disclosed breakable seals can be used in a variety of end uses. Reactive chemicals and food storage and preparation have already been described. The food use includes not only frozen foods heated in a microwave oven or the like, but also storage-stable foods and refrigerated foods. Food applications also include beverage products. Other two or three component reaction systems are also contemplated and cover categories such as adhesives, coatings and fillers.

  Other uses are in the medical field. For example, a multi-compartment pouch can be designed such that when a breakable seal breaks, two or more components are mixed and cured in a short time. Prior to curing, the pouch can cover the body part and, for example, become a support for an injured foot and be cured into a casting to provide support and protection. As a related example, a similar but smaller multi-compartment pouch can be designed, and after mixing the ingredients, before curing, the pouch is placed in the user's ear and when it is cured, it becomes a shape, and a hearing aid custom developed product Used for. In other medical applications, a specific amount of drug can be mixed and dispensed in a multi-compartment pouch to dispense the desired concentration of drug. In some cases, such a pouch can incorporate a hang tab and be used as an intravenous (IV) dispensing bag.

  A useful application in the dental field is mixing pad replacement. With a pre-weighed amount of reagent used for filling the cavity, a multi-compartment pouch can be used to open the breakable seal and then mix in the pouch. Once thoroughly mixed, the pouch can be opened and used for the intended application. Another useful application in the dental field is the creation of impression materials. Multi-compartment pouches can hold reagents used to make dental impression materials and the like. A convenient separate package can be created, eliminating the need to weigh reagents.

  Yet another application is the indicator field. In this application, a multi-compartment pouch can give the user information about conditions such as temperature and pressure to which the pouch is exposed. The break indicator thus created can inform the user of shocks and temperature limits. The pouch can also be used as a seam breaking indicator.

  In the cosmetic field, one useful application is hair color. Multi-compartment pouches can be held separately until components such as developers and color creams are used. Compared to the current method of adding the color cream component contained in the tube to the developer bottle and shaking the open bottle with the finger in the hole, the components can be easily mixed in the pouch. The disclosed multi-compartment pouch can also eliminate the risk of handling only the color cream ingredients that irritate the skin and eyes. In such a case, a spout that can be easily applied to the hair can be incorporated into the pouch. Facial mud is another useful cosmetic application. Multi-compartment pouches can hold mud components such as liquids (milk and water), clays and powder isolates until the breakable seal is broken and the product is mixed and applied.

  Still other uses of the disclosed containers with breakable seals include food or drug mixtures, two-component hot or cold packs, analytical test (releasable) perishable two-component test mixtures, soaps or disinfectants. Disposable hand towels, disposable dental whitening packs, two-component cleaning compounds for dental or other use, complete salad ingredients, partitioned baking ingredients, various food packaging, meat / dipping juice combinations, meat / liquid flavors / Combination of noodles, sauce mixed after heating ingredients, two-component juice pouch, endothermic chemical for cooling, pasta and sauce, rice / chicken / vegetable combination, cleaning fabric with peroxide on one side, carpet or stain cleaner Heated cleaning liquid to be soaked, 2 component or more customization Cosmetics, personal care with special effects such as fizz shampoo, peroxide / colorant hair color, customizable hand lotion / fragrance, kaleidoscope, educational toys using color, built-in chemical experiment kit, borax / Two-component slime toys, chemical coolers and heaters, such as combinations of wood bonds, floaters, light sources, car body fillers, curable paint systems, dissolvable bag retention hardeners, custom pigment dispensing, putty and body fillers , Self-expanding sheets, oxygen-producing components made from fish-permeable oxygen-permeable sheet materials, packaging foam materials, packaging materials in which gas is generated by a combination of acids and bases, two-component foam systems, impact, temperature and pressure Break indicator, seam break indicator and my Something like a black bag valve.

Compartment Design Features The containers disclosed herein can incorporate a variety of design features. For example, a pump spray device can be incorporated into a multi-compartment pouch. In this case, a combined mixture can be dispensed by inserting a dip tube and spray atomizer into one of the compartments. The dip tube can be extended to the bottom of one compartment and when the breachable seal is opened, the two separate components can be mixed around the dip tube to be uniform. The solution can be dispensed using a spray atomizer pump similar to a hair spray dispenser except that a multi-compartment pouch is used.

  The disclosed pouch or container can also incorporate an atomizer / venturi nozzle to dispense the mixed contents of the pouch. The dip tube extends to the bottom of the pouch where the atomizer / venturi device is sealed around the applicator. Pressurized air is connected to the nozzle and the contents of the pouch are sucked out through the atomizer and the contents can be uniformly applied on the selected substrate.

  The disclosed pouch or container can incorporate a pull head or tab as an aid to opening. For example, two pull heads can be secured on opposite sides of the pouch or near a breakable seal. When pulled in the opposite direction, the seal can be easily opened to mix the separate contents. The pull head or tab may include a heat-sealable polyethylene film tab bonded directly to the outside of a higher bond strength pouch than the breakable seal itself.

  The disclosed pouch or container can include a conventional pressure relief valve. As the contents of the pouch are heated and steam is released, the pouch begins to expand. When the pressure in the pouch reaches the set point of the conventional relief valve, the valve opens and steam escapes from the pouch and maintains the pressure within the normal range to prevent the pouch from bursting. Such a relief valve can be added to the fragile overlap region described above.

Experimental A two-component bag formed by heat sealing a strip blown polypropylene web strip seal to the center of a polyethylene bag was obtained using either ASTM-F88-00 or ASTM-F2054-00. The strength of the barrier seal was determined. The first test (ASTM-F88-00) measures the seal strength of a flexible barrier bag. The burst strength measurement uses internal pressurization in a fixed plate as described in the second test method (ASTM-F2054-00).

A. Comparison of blown microfiber (BMF) barrier and effective fiber diameter (EFD) For this comparison, the bag dimensions were 19.7 cm wide and 11.4 cm long. A bag containing a longitudinal barrier strip was made with the Klockner-Ferromatic Bag Maker, model number LA III. The process was conducted at a temperature of about 135 ° C. to about 150 ° C., a dwell time setting of about 2 seconds to about 4 seconds, and a mechanical pressure setting of 1.54 to 1.97 kg / cm ² (22-28 psi) mechanical pressure setting. Pressure press operation was included. The bags of Examples 1-12 were ruptured using an ARO 2600 pressurized air rupture machine with a flow rate setting of 9.0. Examples 1-6 in Table 1 show that at a fixed temperature, the barrier burst strength increases with increasing effective fiber diameter.

  Examples 7-12 in Table 2 show that at fixed temperatures, the barrier burst strength increases with increasing effective fiber diameter and decreasing basis weight. Comparison of the results in Table 1 and Table 2 shows that the barrier burst strength increases as the sealing temperature increases.

B. Blow Microfiber (BMF) Barrier Weighing Comparison For this comparison (Examples 13-23), the bag size was 25.4 cm wide and 26.7 cm long. Bags were made with the Klockner-Ferromatic Bag Maker, model number LA III. The process included a flat press operation with a pause time setting of about 2 seconds to about 4 seconds. The mechanical pressure setting was 1.54 to 1.97 kg / cm ² (22 to 28 psi). During bag manufacture, the supply of strip seal webs between film sheets was optionally supplied mechanically using a barrier strip unwinder or manually. The bag was ruptured using an ARO 2600 pressurized air rupture machine.

  Table 3 shows that at a fixed temperature, the barrier seal burst strength increases with increasing effective fiber diameter and decreasing the microfiber web weigh. Table 4 shows that the bags formed using the machine-feed strip seal differed in burst strength from those produced using the manual feed technique. This difference is likely due to the difference in tension of the strip seal being supplied.

  In the following sections C to I, the samples were sealed and tested in the following manner.

  Heat Seal Description: A seal of heat seal material was made with a Packrite (Racine, WI) model R robot jaw sealer with a 12 inch long sealing rail. The sealer was equipped with heated upper and lower brass rails with a sealing width of 3/16 of an inch. This device had thermocouple feedback to control the temperature of the sealing rail and digital control of the sealing time. The pressure was controlled by air pressure with a clamping cylinder. Specific examples of sealing conditions are given for each example.

  Breakable Seal Test: ASTM F88-, except that when recording peel values for a breakable seal, a peel test was performed on the length of the breakable seal and a rail separation speed of 5 inches / minute was used. It was generated using the same test method as 00. The value recorded for the breakable seal strength is the average of three trips of peeled and separately bonded samples. The value for the control sample is a single peel value.

  The control material annotated for each example refers to a listed heat seal material that is sealed directly to itself without the fibrous strips listed in the sealing region.

C. Effect of seal temperature on breakable seal strength Conditions used:
Heat Seal (Thermoplastic) Film—Scotchpack ES241 consisting essentially of a 0.56 mil PET reinforced layer and a 3.44 mil LLDPE heat seal (thermoplastic) layer.
Fibrous strip material-Polypropylene (PP) homopolymer blown microfiber (BMF) substantially similar to Atofina 3960, but with a small amount of additives that are not problematic for the purposes of this application. The effective fiber diameter was 4.4 microns and the basis weight was 25 grams per square meter (gsm).
Sealing conditions
Rest time = 1.0 sec Sealing pressure = 40 PSI
Sealing temperature = (variable)

  In this set of data, the sealing force is initially very low because the sealing temperature is not high enough to melt the thermoplastic to form a bond. "Tear" means that the seal was strong enough to tear the sheet without seal failure. This can be seen from the bond value of the control sample. The published melting point of the sealing resin is 255 ° F. As the temperature rises, the thermoplastic material flows well during bonding and the sealing force increases. At a temperature of 270 ° F., under this condition, the seal is clear (ie transparent, which is trapped in the breakable seal area) because the thermoplastic polymer seal from each side of the seal contacts through the nonwoven fibrous strip. Is substantially free of air). The seal value continues to increase until the thermoplastic material begins to flow excessively at high temperatures and the flow path pressure in the sealing region begins to extrude the thermoplastic material out of the sealing region, and the two beads at the end of the sealing region or bond And the peel value of the seal is reduced.

D. Effect of sealing down time on breakable seal strength Conditions used:
Heat seal film-(same as section C)
Fibrous strip material-(same as section C)
Sealing conditions
Pause time = (variable)
Sealing pressure = 40 psi or 80 psi
Sealing temperature = 300 ° F

  In this set of data, the seal strength (represented by the peel force) at the lowest pause time is low because the pause time is insufficient to effectively heat and melt the thermoplastic sealing layer. If the rest time is longer than this, the seal strength reaches a relatively constant value and can be used for container applications.

E. Effect of sealing pressure on breakable seal strength Conditions used:
Heat seal film-(same as section D)
Fibrous strip material-(same as section D)
Sealing conditions
Pause time = 2 seconds Sealing pressure = (variable)
Sealing temperature = 300 ° F

  According to Table 8, the seal strength gradually increases over the indicated pressure range, and all breakable seal strength values are in the usable range.

F. Effect of fiber strip basis weight on breakable seal strength Conditions used:
Heat seal film-(Same as Section E)
Fibrous strip material-polypropylene homopolymer BMF, type Atofina # 3960. The actual optically measured fiber diameter is 12 microns. Stock weighs 5, 15, 20 and 30 gsm. Fibrous strip materials were stacked to obtain effective basis weights of 10, 40 and 60 gsm.
Sealing conditions
Rest time = 1 second Sealing pressure = 40 psi
Sealing temperature = 300 ° F

  According to this data, the peel value of the breakable bond is too high at the low basis weight of the fibrous strip material. At higher basis weights, the peel value is in the usable range. As the basis weight increases further, the ability to create a transparent seal with a 1 second downtime is lost.

G. Effect of different thermoplastic heat sealing films on ruptureable seal strength Conditions used:
Heat seal film (see table)
ES33-SCOTCHPAK ES33 containing 0.56 mil PET and 3.44 mil Primacor 3330 ethylene acrylic acid copolymer
ES26- 3.8 mil PET and SCOTCHPAK ES26 containing 2.0 mil Elvax 3185 ethylene vinyl acetate
ES241-SCOTCHPAK ES241 described in Section C
Nylon / PE-3 mil nylon and 2.25 LLDPE
Fibrous strip material-(same as section E)
Sealing conditions
Downtime = (see table)
Sealing pressure = 40 psi
Sealing temperature = (see table)

  This data shows that an effective breakable seal can be made with various thermoplastic heat seal films. Depending on the structure of the heat seal film, different sealing conditions need to be used to obtain a suitable peelable seal peel value.

H. Effect of different sealing strip materials on breakable seal strength Conditions used:
Heat seal film-(Same as Section F)
Fibrous strip material-(various, see table)
Sealing conditions
Rest time = 1.0 seconds Sealing pressure = 40 psi
Sealing temperature = 300 ° F

  Various purchased nonwoven web materials were tested for the ability to make a breakable seal with suitable seal strength. Some were found. In Example 61, the seal is permanent because it is the same polymer in the fibrous strip and the thermoplastic bonding layer. Example 63 also shows this effect of high peel values for PE in a fibrous strip structure. In Example 64, the fibrous strip had a three-layer SMS (spun-bond / meltblown / spunbond) where each layer was composed of polypropylene (PP). Other blown microfibers and SMS structures had values in the preferred peel value range.

I. Effect of sealing configuration on breakable seal strength Conditions used:
Heat seal film-(Same as Section H)
Fibrous strip material-(same as section G)
Sealing conditions
Pause time = (variable, see table)
Sealing pressure = 40 psi
Sealing temperature = 300 ° F

  In Table 12, “tape layer” refers to the layer of 3M60 PTFE film (2 mil PTFE tape) used to cover the sealing rail. The data in Table 12 shows that various heat rail configurations can be used to produce breakable seals with appropriate peel values. This includes heating the seal from one or both sides and having one or both sealing rails covered with a tape layer.

Food Examples In these examples, different combinations of food ingredients were filled into adjacent compartments of a two-compartment plastic pouch. A pouch was constructed using a film laminate sheet similar to the SCOTCHPAK 29905 sheet described above, but with a chain low density polyethylene layer constructed from Dow Chemical Co. Dowlex 2035LLDPE. . Prior to filling the compartment with food, the pouch was substantially the design shown in FIGS. A strip seal composed of a meltblown polypropylene web with a width of about 12 mm and slit was used. Pouches were manufactured with the Klockner-Ferromatic Bag Maker, model number LA III. The size of the pouch is about 25.4 cm (10 inches) wide, the size of “2 people” is about 26.7 cm (10.5 inches) in length, and the size of “one person” is about 16.5 cm (6 inches). .5 inches). After filling the substantially equal-sized compartments with the selected food ingredients, the open end of the pouch was sealed at the end, and the resulting food preservation article was placed in the freezer compartment of a conventional refrigerator-freezer. Then, for testing, remove the fully frozen food storage item from the freezer and immediately place it in a General Electric model number JES1339WC001 turntable microwave oven with an output rating of 1.53 kW and turn the range on at the “high” setting I made it. The compartment vapor pressure was increased and the time at which the breakable seal broke due to internal vapor pressure was recorded. In all cases, the pouch end seal remained intact and the food ingredients could be cooked for an additional period of time after the barrier seal broke.

F1 cheese ravioli / red sauce (one serving)
In this example, one section of the pouch was filled with about 221 g of cheese-filled ravioli pasta, and multiple sections were filled with about 119 g of tomato sauce. These ingredients were cooked separately for about 2 minutes and 27 seconds before observing breakage of the barrier seal. The contents of the pouch were cooked together for another 35 seconds before the microwave was turned off. The pouch was removed from the oven and opened. The food had good softness and both components were hot.

F2 noodles / square-cut chicken and vegetables (one serving)
In this example, about 119 g of frozen noodle dough was filled in one section of the pouch, and about 51 g of chopped pre-cooked chicken and about 61 g of uncooked vegetables were filled in the other section. These ingredients were cooked separately (separating the noodles from chicken and vegetables) for about 1 minute 51 seconds, and then the barrier seal was observed for breakage. The contents of the pouch were cooked together for another 33 seconds before turning off the microwave. The pouch was removed from the oven and opened. All ingredients in the food were hot. The vegetables had good crunchy (not stretched) softness, but the noodles were dry and had a hard side.

F3 noodles / square-cut chicken, vegetables and white sauce (one serving)
In this example, about 119 g of frozen noodle dough was filled in one section of the pouch, and about 51 g of chopped pre-cooked chicken, about 61 g of uncooked vegetables and about 109 g of white sauce were filled in the other section. These ingredients were cooked separately (separating the noodles from chicken, vegetables and sauce) for about 1 minute 52 seconds before observing breaks in the barrier seal. The contents of the pouch were cooked together for an additional 10 seconds before the microwave was turned off. The pouch was removed from the oven and opened. The food had hot and cold parts. The noodles were dry and had a hard side.

F4 Rice / Square-cut chicken and vegetables (for two)
In this example, one section of the pouch was filled with about 238 grams of cooked rice and the other section was filled with about 102 grams of chopped pre-cooked chicken and about 122 grams of uncooked vegetables. These ingredients were cooked separately (separate rice from chicken and vegetables) for about 5 minutes and 13 seconds before observing breakage of the barrier seal. We cooked the contents of the pouch together and turned off the microwave. The pouch was removed from the oven and opened. All ingredients in the food were hot. The vegetables had good softness (not stretched), and the rice also had good softness.

F5 rice / cut chicken, vegetables and white sauce (for two)
In this example, one section of the pouch was filled with about 238 grams of cooked rice and the other section was filled with about 102 grams of chopped pre-cooked chicken, about 122 grams of uncooked vegetables and about 218 grams of white sauce. These ingredients were cooked separately (separate rice from chicken, vegetables and sauce) for about 6 minutes 19 seconds before observing barrier seal rupture. We cooked the contents of the pouch together and turned off the microwave. The pouch was removed from the oven and opened. The food had hot and cold parts.

  Further practice of food examples. In one example, cheese was placed in one compartment and nacho chips were placed in the other compartment. In another example, cheese was placed in one compartment and a large soft pretzel was placed in the other compartment. In these cases, the barrier seal broke again from the vapor pressure without breaking the pouch end seal in the compartment. After cooking, when all the food ingredients were well heated, the resulting food had good quality and taste.

  Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and purpose of this invention, and this invention is not considered to be limited to the illustrative embodiments defined herein. .

FIG. 5 is a plan view of a pouch including a seal that can be broken before filling the individual compartments with suitable contents and an end that seals the closed pouch. It is a fragmentary top view of the edge part vicinity of the deformation | transformation embodiment of FIG. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. It is a general | schematic expanded sectional view of the edge part of the breakable seal | sticker. FIG. 2 is a plan view of a pouch similar to FIG. 1 except that an inflatable portion is incorporated into one of the compartments. 1 is a plan view of a multi-compartment pouch that includes multiple breakable seals that form three or more compartments. 1 is a plan view of a multi-compartment pouch that includes crossed microfiber strip seals that form multiple breakable seals in a four-compartment pouch. FIG. 6 is a plan view of a two-compartment pouch incorporating a combination breakable seal and a permanent seal to improve mixing characteristics. FIG. 8 is a partial plan view of the modified embodiment of FIG. 7. FIG. 2 is a schematic cross-sectional view of a container having a molded rigid plastic base and a cover sheet bonded together with at least one breakable seal. FIG. 5 is a plan view of a single compartment pouch incorporating the disclosed breakable seal as an opening.

Claims (16)

First and second thermoplastic polymer layers;
A third continuous polymer layer disposed between the first and second polymer layers;
A breakable seal comprising
The first and third polymer layers form a first physical polymer blend;
A breakable seal wherein the second first and third polymer layers form a second physical polymer blend.   The seal of claim 1, wherein the third continuous polymer layer comprises a fibrous strip comprising non-woven microfibers.   The first and second physical polymer blends define a seal region of the breakable seal, and the third continuous polymer layer includes an end portion spaced from the seal region. The seal according to 1.   A container comprising the seal according to claim 1. A container comprising a first thermoplastic sheet sealed to a second member along at least one permanent seal and at least one breakable seal to define a first compartment within the container;
A container in which a continuous fibrous strip containing microfibers is disposed between the first sheet and the second member to form the breakable seal.   The container according to claim 5, wherein the second member includes a second thermoplastic sheet.   The container according to claim 5, wherein the first thermoplastic sheet includes an inner thermoplastic layer and an outer reinforcing layer.   The container of claim 5, wherein the container includes a second compartment, and the breakable seal separates the first and second compartments.   The container according to claim 4 or 5, wherein the container holds a food product.   A food storage article comprising the container of claim 8 and further comprising a first food ingredient sealed in the first compartment and a second food ingredient sealed in the second compartment.   The food storage article of claim 10, wherein one of the first and second compartments includes an inflatable portion. Providing the food storage article according to claim 10;
Heating the food storage article until the breakable seal is broken by vapor pressure in at least one of the first and second compartments;
How to cook food containing.   13. The method of claim 12, wherein the pouch further includes an end seal around it that does not break when the breakable seal breaks. Providing first and second transparent thermoplastic sheets;
Disposing a continuous fibrous strip comprising non-woven microfibers between the first sheet and the second sheet to form a multilayer structure;
Applying sufficient heat and pressure to the multilayer structure in a sealing region to form the breakable seal;
A method of manufacturing a breakable seal comprising:   15. A method according to claim 14, wherein the applying step provides a transparent breakable seal.   The method of claim 14, wherein the fibrous strip is larger in size than the sealing area.

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