US20170113864A1 - Package system and method for inhibiting moisture entry - Google Patents

Abstract

A package system for maintaining the physicochemical integrity of the contents of the package system that includes: an inner bag formed from a gas and/or moisture permeable material, an outer bag formed from an impermeable polymer material, a discharge port that provides access to the interior of the outer bag; and a desiccant or gas scavenging material. The first end of the outer bag sealingly surrounds the exterior wall of the discharge port. The second end of the inner bag is sealed closed and the desiccant or gas scavenging material is disposed in an isolated compartment. The second end of the outer bag is sealed closed to isolate the interior from the environment exterior to the package system.

Description

• This application claims priority from International patent application No. PCT/US2015/022981, filed on Mar. 27, 2015, which claims priority from U.S. provisional application Ser. No. 61/971,003, filed on Mar. 27, 2014, both of which are incorporated herein in their entirety.
FIELD OF THE INVENTION
• The present invention is a package system that maintains the physicochemical integrity of its contents, free-flowing characteristics. In particular, the present invention relates to package systems that prevent the caking of salts used in the manufacture of biopharmaceuticals (e.g., in cell culture production).
BACKGROUND OF INVENTION
• Various salts and buffers are used in the manufacturing operations associated with biopharmaceuticals production (e.g., cell culture production and protein purification). These chemicals are dissolved under sterile conditions to make up a variety of solutions. A common problem with delivering granular solids is that they have a tendency to cake (i.e., joined together to form a mass) due to the presence of moisture in the solid. The moisture can come from two sources, externally and internally. Internal moisture is found on the surface of the salt and it can be released when there are changes in temperature. External moisture enters the package system from the environment exterior to the package system. Caking of solids is a major problem in the industry and attempts to solve this problem include adding anti-caking agents and changing the crystal size. However, none of these attempts have completely solved the problem. The addition of anti-caking agents to packages containing salts is undesirable because the anti-caking agents frequently include compounds that interfere with the pharmaceutical manufacturing process.
• Salts tend to cake together during storage due to migration of free moisture present on the surface of the salt or due to migration of moisture from the outside environment. The mechanism of caking is the result of the formulation of small salt bridges between the particles due to a partial dissolving of the salt contacted by the free moisture. Over time the bridges become stronger and, when a sufficient amount of moisture is present, the product can turn into a solid unusable mass. Temperature changes in the environment help to release free moisture on the surfaces of these materials and caking increases the more the temperature changes.
• A package system that prevents salts from caking is disclosed in U.S. Pat. No. 6,102,198 to Mallinckrodt, which utilizes a moisture permeable bag to allow the moisture to pass from the salts through the bag into the desiccants placed around the bag—either underneath, on top or on the sides of the bag. Any free moisture in the salts or that enters from the outside is trapped (i.e., absorbed) by the desiccants. This system has some drawbacks, including a drum that is expensive and can be difficult for the user to empty. Moreover, with larger drums (60 Kg and above), the moisture removal through the large solid bed is not faster. Typically, these larger systems exhibit clumping in the center and in the areas distant from the desiccant; while the material near the desiccant is clump free, resulting in a partially clumped product.
• Therefore, there is a need for new package systems that can remove free moisture from its contents and prevent caking until the contents of the package have been completely consumed. The system should maintain free flowing (cake free) material uniformity thought the drum/package. The location of the desiccant should be selected so that it cannot migrate or break-up and contaminate the product. The package system should also be designed to provide direct dispensing of the product into a reactor/mixing vessel through a port and permit spectroscopic (Raman spectroscopy) analysis of the product without opening the inner bag and risking product contamination. Additionally, the package system should prevent outside moisture from passing water through the walls of the package into the inside of the package.
SUMMARY OF THE INVENTION
• In accordance with the present invention, a package system for inhibiting moisture entry into the contents of the package and continuous removal of any free moisture in the contents is provided. In a preferred embodiment, the package system has a first end and a second end and comprises, consists of or consists essentially of: an inner bag, an outer bag, a discharge port, a pressure equalizing port and at least one desiccant or gas scavenging material. The inner bag is formed from a gas and/or moisture permeable material and has an interior, a first end and a second end. The outer bag is formed from a gas and/or moisture impermeable polymeric material (e.g., HDPE, various LDPEs, and other similar polymeric materials) and has a first end and a second end. The outer bag is also clear to facilitate rapid identification of the package system's contents by Raman spectroscopy (e.g., a handheld Raman spectrometer).
• The discharge port has an exterior wall that defines an interior passage that provides access to the interior of the outer bag. The pressure equalizing port vents air from the interior of the inner bag, when it is being filled, and allows filtered or inert gas to enter the interior, when the inner bag is being emptied. The desiccant(s) or gas scavenging material can be a moisture or gas absorbing material that can be used safely with pharmaceutical products.
• The inner bag is formed from a layer of a gas and/or moisture permeable material and has a first end, a second end and opposing side edges. The side edges are sealingly attached to the side wall on the interior of the outer bag from the second end of the outer bag. The first end of the inner bag is attached to the interior of the outer bag at a point intermediate the first and second ends of the outer bag or to the exterior wall of the discharge port to form a second compartment. After the first end of the inner bag is sealingly attached to the exterior wall of the discharge port, the first end of the outer bag sealingly surrounds the first end of the inner bag and the entire exterior wall of the discharge port to form an intermediate space (also referred to herein as a first compartment) between the inner bag and the side wall of the outer bag. The outer bag can be comprised of two layers and preferably can be formed as one continuous layer for increased product strength by extruding the outer bag as a tube or sleeve.
• After desiccant(s) and/or gas scavenging material are disposed inside the inner bag (also referred to herein as the second compartment), the second end of the inner bag is sealed closed. The bottom end of the inner bag that contains the desiccant material can be heat sealed or fused along a line that extends horizontally and parallel to the second end of the inner bag. The heat seal is located at least 4 inches above the bottom port, preferably a minimum of 5 inches from the bottom port and most preferably 6 or more inches. The function of this seal is to keep the inner bag containing the desiccant away from the discharge port so that it does not impede the flow of material during emptying operations. After the desiccant material is added to the inner bag, the second ends of the inner and outer bags are sealed closed to isolate the intermediate space from the environment exterior to the package system. The HDPE liner does not include slip agents or block agents; however, an antistatic agent can be added to the HDPE liner to ensure that all of the product is delivered and prevents sticking of the product to the walls due to static buildup.
• In a second embodiment, the first end of the inner bag is sealingly attached to the exterior wall of the discharge port and the first end of the outer bag sealingly surrounds the first end of the inner bag and is sealingly attached around the exterior wall of the discharge port to form an intermediate space (also referred to herein as a compartment or the second compartment) between the inner bag and the outer bag. The desiccant(s) and/or gas scavenging material are disposed in the intermediate space and the second end of the inner bag is sealed closed. The function of this seal at the bottom end of the inner bag is to keep the inner bag from falling to the bottom of the package system and impeding the flow of material through the discharge port during emptying operations. The second end of the outer bag is then sealed closed to isolate the intermediate space (i.e., first compartment) from the environment exterior to the package system. HDPE liner does not include slip agent, or block agents, however an antistatic agent is added to the HDPE liner to ensure that all of the product is delivered and prevents sticking of the product to the walls due to static buildup.
• The discharge port is used to fill and discharge materials contained in the interior of the inner bag. The first end of the HDPE outer bag forms a seal around the exterior wall of the discharge port. The discharge port is located at the bottom of the packaging system in the HDPE outer bag. The discharge port can have a removable cap for closing and sealing the discharge port. The removable cap isolates the contents of the package system from the outside environment during transportation and storage. The package system can also include a handle attached to the second end of the package system to facilitate the handling of the package system by the user.
• The pressure equalizing port is located near the second end of the package system and has a passage that extends between the interior of the inner bag and the environment exterior to the package system. The passage of the pressure equalizing port contains one or more filter materials that contain at least one desiccant and/or gas scavenging materials, which can selectively prevent moisture or certain gases from entering the interior of the inner bag. The pressure equalizing port can also facilitate the introduction of dry inert gas to blanket the material in the inner bag.
• The gas permeable material of the inner bag is preferably formed from continuous and very fine fibers of randomly distributed and non-directional high-density polyethylene. The gas impermeable material of the outer bag preferably includes a low density or a high density polyethylene. The gas impermeable material can include at least three layers with an inner layer formed from a gas barrier material. In a preferred embodiment, the gas barrier material of the inner layer is an ethylene/vinyl alcohol copolymer or polychlorotrifluoroethene.
• In another embodiment, the package system has a first end and a second end and comprises, consists of or consists essentially of: a first plastic layer, a second plastic layer, a layer of permeable material disposed between the first and second plastic layers, a discharge port, a pressure equalizing port and at least one desiccant or gas scavenging material. The first and second plastic layers are preferably made of substantially gas impermeable plastic, most preferably from HDPE and/or LLDPE, and at least one of the layers is transparent. The permeable inner layer is preferably made of an ethylene/vinyl alcohol copolymer or polychlorotrifluoroethene. The three layers have substantially the same dimensions and the outer edges are aligned and sealed by a well-known method (e.g., heat stamping or ultrasonic welding) to form a bag with first and second compartments separated by the gas permeable layer.
• The first end of the package system is attached to the handle and the pressure equalizing port is located in the first plastic layer near the first end. The discharge port is located in the first plastic layer near the second end. The first compartment is disposed between the first plastic layer and the permeable layer and contains the contents, such as salts used in the manufacture of biopharmaceuticals. The desiccant and/or gas scavenging agent(s) are placed in the second compartment between the second plastic layer and the gas permeable layer. The second compartment is segregated from the first compartment so that the desiccant and/or scavenging agents are isolated from the contents, such that they are not unintentionally poured out with the contents of the first compartment. The pressure equalizing port vents air from the interior of the first compartment, when it is being filled, and allows filtered or inert gas to enter the interior, when the first compartment is being emptied. Optionally, a port can be located in the second plastic layer for adding and removing desiccants and/or gas scavenging agents.
• Another embodiment of the package system includes an outer bag, one or more inner bags and at least one desiccant or gas scavenging material. The outer bag includes a sheet of a gas and/or moisture impermeable polymer material and has an interior. Each of the inner bags includes a sheet of a gas and/or moisture permeable material disposed in the interior of the outer bag and each sheet has a perimetrical edge that is sealingly attached to the sheet of gas and/or moisture impermeable polymer material of the outer bag. The at least one desiccant or gas scavenging material is disposed between each of the sheets of gas and/or moisture permeable material and the sheet of gas and/or moisture impermeable polymer material.
• Preferably, the outer bag can include two sheets of gas and/or moisture impermeable polymer material, each sheet having a perimetrical edge extending along first and second sides and first and second ends. The perimetrical edges of the two sheets are sealed together at least on two sides and one end. More preferably, the sheet of a gas and/or moisture impermeable polymer material is formed as a tube having a first end and a second end. The second end is sealed to form the outer bag.
• Another embodiment of the package system includes an outer bag, one or more inner bags and at least one desiccant or gas scavenging material. The outer bag includes a perimetrical side wall formed from a gas and/or moisture impermeable polymer material. The perimetrical side wall includes in order a front sheet, a first side sheet, a rear sheet and a second side sheet. The outer bag has an interior, a first end and a second end. Each of the one or more inner bags includes a sheet of a gas and/or moisture permeable material disposed in the interior of the outer bag. The sheet has a perimetrical edge that is sealingly attached to the front or rear sheet of gas and/or moisture impermeable polymer material. The at least one desiccant or gas scavenging material is disposed between the sheet of gas and/or moisture permeable material and the sheet of gas and/or moisture impermeable polymer material. The first and second side sheets can have one or more pleats.
• The first end of the outer bag can be sealing closed by a top sheet formed from a gas and/or moisture permeable material and the first end of the outer bag can have a fill port. Preferably, the second end of the outer bag is sealing closed by a bottom sheet formed from a gas and/or moisture permeable material and the second end of the outer bag can have a discharge port.
• Another embodiment of the package system includes an outer bag, one or more inner bags and at least one desiccant or gas scavenging material. The outer bag includes a perimetrical side wall formed from a gas and/or moisture impermeable polymer material. The perimetrical side wall includes, in order, a front sheet, a first side sheet, a rear sheet and a second side sheet. The front, rear and side sheets define two pairs of diagonally opposed corners. The outer bag has an interior, a first end and a second end. The one or more inner bags are disposed in the interior of the outer bag. Each of the inner bags includes two sheets formed from a gas and/or moisture permeable material and has a perimetrical edge. The perimetrical edges of the sheets are sealed together to form one of the one or more inner bags. Each inner bag has an enclosed space and first and second side edges. One side edge of a first inner bag is attached to one of the diagonally opposed corners. The at least one desiccant or gas scavenging material is disposed in the enclosed space of each of the inner bags. The first side edge of a second inner bag is attached to the corner diagonally opposite the first inner bag. At least one member connects the second side edges of the first and second inner bags.
• The first and second side sheets can have one or more pleats. Each of the first and second ends of the outer bag can be sealing closed by a top sheet and bottom sheet, respectively, formed from a gas and/or moisture permeable material. The first end of the outer bag can have a fill port and the second end can have a discharge port. Each of the fill port and the discharge port can have a removable cap for closing the fill port or discharge port and sealingly isolating the interior of the outer bag from the exterior environment.
• For all of the embodiments disclosed above, the ratio of the area of the sheet of gas and/or moisture impermeable polymer material to the area of the one or more sheets of gas and/or moisture permeable material is from about 10:1 to about 2:1. The gas and/or moisture impermeable polymer material of the outer bag can include a low density or a high density polyethylene. The gas impermeable material can include at three or more layers with a middle or interior layer formed from a gas barrier material. The gas barrier material of the middle or interior layer can be an ethylene/vinyl alcohol copolymer or polychlorotrifluoroethene. The layer of gas and/or moisture permeable material is formed from a cloth or continuous and very fine fibers of randomly distributed and non-directional high-density polyethylene.
• For long term storage of the package system with product inside the inner bag, an over bag is placed over the primary bag and heat sealed closed. The over bag serves as a moisture barrier and further isolates the product in the package system from moisture. The over bag can be composed of a Mylar®-type material (i.e. a layer of polyester or polyethylene terephthalate (PET) film) that has a very low moisture transmission rate.
BRIEF DESCRIPTION OF THE FIGURES
• The preferred embodiments of the package system of the present invention, as well as other objects, features and advantages of this invention, will be apparent from the accompanying drawings wherein:
• FIG. 1 is a side view of a first embodiment of the package system of the present invention.
• FIG. 2 is a side view of the embodiment of the package system inFIG. 1 showing the outer bag and inner bag.
• FIG. 3 is a side view of the embodiment of the package system inFIG. 1 showing the inner and outer.
• FIG. 4 is a side view of the embodiment of the package system inFIG. 1 showing the outer bag with a transparent panel and window for viewing the contents.
• FIG. 5 is a perspective view of the pressure equalizing port and filter system of the package system shown inFIG. 1.
• FIG. 6 is a perspective view of the cap and locking ring for the pressure equalizing port shown inFIG. 5.
• FIG. 7 is a top view of the locking ring for the pressure equalizing port shown inFIG. 5.
• FIG. 8 is a side view of the embodiment of the package system inFIG. 1 showing the handle.
• FIG. 9 is a side view of a second embodiment of the package system having two compartments separated by a gas permeable layer attached to the discharge port.
• FIG. 10 is a front view of the package system shown inFIG. 9 with the handle removed to show the relationship of the three layers that form the package system.
• FIG. 11 is a front view of the package system shown inFIG. 9 enclosed in an over bag.
• FIG. 12 is a photograph of the package system after testing in a stability chamber.
• FIG. 13 is a photograph of a prior art package system after testing in a stability chamber.
• FIG. 14 a side view of a third embodiment of the package system having an outer bag formed by two plastic sheets and a plurality of inner bags formed on the interior surface of the outer bag.
• FIG. 15 a side view of a fourth embodiment of the package system having an outer bag formed by two plastic sheets and two inner bags with one side of each inner bag attached to the edge of the outer bag and the opposing sides joined by a pair of members.
• FIG. 16 a side view of a fifth embodiment of the package system having an outer bag formed by five plastic sheets—a front sheet, a rear sheet, a pair of side sheets and a bottom sheet—and two inner bags with one side of each inner bag attached to the opposing corner edges of the outer bag and the opposing sides joined by a pair of members.
• FIG. 17 a side view of a sixth embodiment of the package system having an outer bag formed by six plastic sheets—a front sheet, a rear sheet, a pair of side sheets, a bottom sheet and a top sheet—and two inner bags with one side of each inner bag attached to the opposing corner edges of the outer bag and the opposing sides joined by a pair of members. The bottom sheet has a discharge port.
• FIG. 18 a side view of a seventh embodiment of the package system having an outer bag formed by six plastic sheets—a front sheet, a rear sheet, a pair of side sheets, a bottom sheet and a top sheet—and two inner bags formed on the interior surface of the outer bag.
• FIG. 19 is a photograph of a drum with the third embodiment of the package system shown inFIG. 14 inside the drum with material in the packaging system.
• FIG. 20 is a photograph of a drum with the third embodiment of the package system shown inFIG. 14 inside the drum with no material in the packaging system.
• FIG. 21 a side view of an eighth embodiment of the package system having an outer bag formed and an inner bags formed near the top of the bag on the interior surface of the outer bag.
DETAILED DESCRIPTION OF THE INVENTION
• The present invention is a package system that reduces the caking of products contained in the package system, preferably salts, due to moisture. Prevention of solids from clumping requires active removal of the free moisture from the material during shipping and storage. The package utilizes a moisture barrier film that prevents the migration of outside moisture through the walls of the package and into the inside of the package and removes free moisture present in the package. Caking is prevented by removing excess water covering all particles even when they are packed in a bulk package. The package system removes excess moisture in the crystals. In one embodiment, the package system includes a gas, vapor, and/or moisture permeable inner bag that contains the product and a moisture and/or gas impermeable outer bag that encloses the inner bag and creates an intermediate space between the inner bag and the outer bag. The key to preventing caking of the product due to moisture is keeping the inner bag at the correct moisture and gas level and capturing any free moisture or gas that may be released by the product (e.g., salts) as a result of temperature changes in the environment. Moisture is uniformly removed from the product by forming the inner bag using a gas permeable material that transmits moisture (i.e., water vapor) through the wall of the bag to the intermediate space. The intermediate space contains materials that absorbs moisture, oxygen and/or selected gasses (e.g., HCl). The space can also be filled with an inert gas.
• As used herein, the term “outer bag” refers to the enclosed structure formed by the impermeable, exterior walls of the package system. The term is used interchangeably with the term “first compartment.”
• As used herein, the term “inner bag” refers to the enclosed structure inside the outer bag of the package system that has at least one wall formed by a permeable material and receives the desiccant. The term is used interchangeably with the term “second compartment.”
• As used herein, the term “layer” refers to one or more layers of polymeric material that are formed into a single layer structure. The layers can be formed from the same polymer or different polymers. With regard to the permeably layer, the layer or layers can be formed from a polymer or from a woven cloth or synthetic material.
• As used herein, the term “impermeable” refers to a material through which substances, such as liquids or gases, cannot pass or can only pass in very small amounts.
• As used herein, the term “permeable” refers to a material through which substances, such as liquids or gases (including water vapor), can pass freely but substantially prevents the passage of solid materials.
• As used herein, the term “desiccant” refers to a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its vicinity. The desiccants are preferably pre-packaged solids that adsorb water. In preferred embodiments, the desiccant material is clay, molecular sieves, or silica. Most preferably, the desiccant material is composed of molecular sieves, which exhibit moisture removal capacity at elevated temperatures to provide moisture removal over a wide range of temperatures.
• As used herein, the term “unit” refers to a quantity of desiccant, which will absorb a set percentage of its weight at certain levels of humidity. For this disclosure, one “unit” is approximately equal to one ounce.
• As used herein, the terms “fused” or “fusion” refer to a method of sealing two or more layers of polymeric materials together by applying heat at a temperature above the highest melting point of the two or more polymeric materials. Ultrasonic welding is one method of fusion. When the two or more layers of polymeric materials cool, they are sealed together in the areas where the heat was applied.
• As used herein, the terms “gusset,” “pleat,” “pleated” or “accordion fold” refer to a diamond-shaped or triangular side wall configuration, formed by folding the plastic sheet that forms the side wall of a bag by doubling the sheet back upon itself and securing it in place at the top and bottom. In a folded condition, the pleats lay together and the bag is substantially flat with the front of the bag contacting the rear. In an unfolded condition, the pleated side walls separate and the volume of the bag increases. In preferred embodiments, the pleats in the side walls extend along the top and bottom walls of the bag so that the bag forms a six-sided structure when the pleats are completely unfolded.
• The package system must also protect the product and maintain the integrity of the product, e.g., keeping the product sterile, dry, and clump free. It was discovered that placing moisture removing material between an inner bag and an outer bag resulted in a moisture deficient area surrounding the product that eliminated product clumping. Package systems that were previously used had the moisture removing agent on top of the product and often experienced clumping. Additionally, some materials are sensitive to oxygen and need to be maintained in an inert oxygen free environment. Another feature of the package system is that the product can be dispensed directly into the reactor system without contacting the outside environment and affecting the integrity of the product. This is preferably accomplished using a discharge port on one end of the package system, preferably about fl-inches in diameter, and a pressure equalizing port located at the other end of the package system. The pressure equalizing port allows filtered air or an inert gas to enter the package system as the product is removed to prevent a vacuum from forming and to ensure continuous flow of the product.
• In a preferred embodiment, the package system has an inner bag surrounded by an outer bag. The inner bag has a first end that is connected to a discharge port and an inner wall formed from a gas permeable material that extends from the discharge port to a sealed second end. The first end of the outer bag is joined to the first end of the inner bag around the discharge port and a surrounding outer wall extends co-extensively with the inner wall to form an intermediate space around the inner bag. A desiccant or other moisture absorbing material (gas or oxygen absorbing materials may also be added) is placed in the intermediate space and then the second end of the outer bag is sealed over the second end of the inner bag. The second end of the package system (i.e., the second ends of the inner and outer bags) can be attached to a handle that can be used for transporting, hanging or securing the package system and its contents during use or storage.
• A pressure equalizing port can be located near the second end of the package system to provide a passage between the interior of the inner bag and the outside environment. The pressure equalizing port can be connected to an inert gas source, such as nitrogen, at a low pressure to maintain an “inert gas blanket” between the contents of the inner bag and the outside environment. Alternatively, the pressure equalizing port can be connected to a filter system that allows the interior of the inner bag to “breathe” the air from the outside environment. The filter system can be formed by a cylindrical tube and can contain one or more filters that filter out moisture, oxygen and/or other gasses that could potentially contaminate the product in the package system. Preferably, the filter material includes at least one desiccant or gas scavenging material. The end of the filter opposite the pressure equalizing port can be sealed with a locking cap, which is used when the package system is being shipped or stored. When the contents of the package system are being removed through the discharge port, the cap on the filter system is removed so that outside air can enter the filter system and pass through the pressure equalizing port to facilitate the delivery of the package system contents.
• The package system includes an inner bag formed from a moisture permeable, porous material layer, such as a cloth or Tyvek®, and an outer bag formed from a non-porous layer, e.g., any one of several different polyethylenes. The preferred permeable materials have water vapor permeation properties. The porous material layer allows water vapor to pass in order to prevent moisture build-up in the inner bag that contains the product. The cloth is typically produced by weaving or knitting textile fibers, such as wool, cotton or a similar fiber or threads made from polymeric materials. Tyvek® is the preferred material for the porous layer and it is manufactured by E. I. Du Pont De Nemours and Company, Wilmington Del. Tyvek® is formed using continuous and very fine fibers of high-density polyethylene, preferably 100 percent high-density polyethylene, that are randomly distributed and non-directional. These fibers are first flash spun, then laid as a web on a moving bed before being bonded together by heat and pressure—without the use of binders, sizers or fillers. By varying both the lay-down speed and the bonding conditions, the flashspun layer can be engineered to form either soft-structure or hard-structure Tyvek®.
• A portion of the inner bag wall can be transparent so that the contents of the inner bag can be viewed through the wall of the transparent or semi-transparent outer bag. The transparent portion of the inner bag wall does not have to be gas permeable and can be formed by a panel or by a window. Such windows or panels are commonly used in the packaging industry so that the contents can be viewed and one of ordinary skill in the art would be familiar with the methods used to form such transparent portions.
• The package system has an outer bag with an outer bag structure, also referred to herein as the exterior film structure. In particular, the present invention relates to exterior films structures made of copolymers of polyethylene; although polypropylene films can also be used. For the purposes of this disclosure, the terms “polyethylene film” or “polyethylene layer” are intended to include any one of the types of polyethylene that are disclosed below, as well as multi-layer films that contain two or more types of polyethylene, e.g., a layer of high density polyethylene and a layer of low density polyethylene.
• Polyethylene is the name for a polymer whose basic structure is characterized by the chain —CH₂CH₂)_n. Polyethylene homopolymer is generally described as being a solid, which has a partially amorphous phase and partially crystalline phase with a density of between 0.915 to 0.970 g/cm³. The relative crystallinity of polyethylene is known to affect its physical properties. The amorphous phase imparts flexibility and high impact strength while the crystalline phase imparts a high softening temperature and rigidity.
• Unsubstituted polyethylene is generally referred to as high density homopolymer and has a crystallinity of 70 to 90 percent with a density between about 0.96 to 0.97 g/cm³. Most commercially utilized polyethylenes are not unsubstituted homopolymer but instead have C₂-C₈alkyl groups attached to the basic chain. These substituted polyethylenes are also known as branched chain polyethylenes. Also, commercially available polyethylenes frequently include other substituent groups produced by copolymerization. Branching with alkyl groups generally reduces crystallinity, density and melting point. The density of polyethylene is recognized as being closely connected to the crystallinity. The physical properties of commercially available polyethylenes are also affected by average molecular weight and molecular weight distribution, branching length and type of substituents.
• People skilled in the art generally refer to several broad categories of polymers and copolymers as “polyethylene.” Placement of a particular polymer into one of these categories of “polyethylene” is frequently based upon the density of the “polyethylene” and often by additional reference to the process by which it was made since the process often determines the degree of branching, crystallinity and density. In general, the nomenclature used is nonspecific to a compound but refers instead to a range of compositions. This range often includes both homopolymers and copolymers.
• For example, “high density” polyethylene (HDPE) is ordinarily used in the art to refer to both (a) homopolymers of densities between about 0.960 to 0.970 g/cm³and (b) copolymers of ethylene and an alpha-olefin (usually 1-butene or 1-hexene), which have densities between 0.940 and 0.958 g/cm³. HDPE includes polymers made with Ziegler or Phillips type catalysts and is also said to include high molecular weight “polyethylenes.” In contrast to HDPE, whose polymer chain has some branching, are “ultra high molecular weight polyethylenes” which are essentially unbranched specialty polymers having a much higher molecular weight than the high molecular weight HDPE.
• Hereinafter, the term “polyethylene” will be used (unless indicated otherwise) to refer to ethylene homopolymers as well as copolymers of ethylene with alpha-olefins and the term will be used without regard to the presence or absence of substituent branch groups.
• Another broad grouping of polyethylene is “high pressure, low density polyethylene” (LDPE). The polyethylene industry began in the 1930s as a result of the discovery of a commercial process for producing LDPE by Imperial Chemical Industries, Ltd. researchers. LDPE is used to denominate branched homopolymers having densities between 0.915 and 0.930 g/cm³as well as copolymers containing polar groups resulting from copolymerization, e.g. with vinyl acetate or ethyl acrylate. LDPEs typically contain long branches off the main chain (often termed “backbone”) with alkyl substituents of 2 to 8 carbon atoms.
• In the 1970s, a new grouping of polyethylene was commercialized—Linear Low Density Polyethylene (LLDPE). Only copolymers of ethylene with alpha-olefins are in this group, LLDPEs are presently recognized by those skilled in the art as having densities from 0.915 to 0.940 g/cm³. The alpha-olefin utilized is usually 1-butene, 1-hexene, or 1-octene and Ziegler-type catalysts are usually employed (although Phillips catalysts are also used to produce LLDPE having densities at the higher end of the range).
• In the 1980s, yet another grouping of polyethylene came into prominence—Very Low Density Polyethylene (VLDPE), which is also called “Ultra Low Density Polyethylene” (ULDPE). This grouping like LLDPEs comprise only copolymers of ethylene with alpha-olefins, usually 1-butene, 1-hexene or 1-octene and are recognized by those skilled in the art as having a high degree of linearity of structure with short branching rather than the long side branches characteristic of LDPE. However, VLDPEs have lower densities than LLDPEs. The densities of VLDPEs are recognized by those skilled in the art to range between 0.860 and 0.915 g/cm³.
• Various types of polyethylene resins have long been used to produce films having different properties. These polyethylenes have been used alone, in blends and with copolymers in both monolayer and multi-layer films for packaging applications for such food products. In the food industry, greater use of centralized processing of foods in conjunction with increased handling and long distance transportation have increased the demand for packaging films having superior properties.
• In the packaging industry, films are known to use coextruded, extrusion coated or laminated films which utilize such compositions as LLDPE, nylon, polyester, copolymer of vinylidene chloride (PVDC), ethylene-vinyl acetate copolymer (EVA) and ionomers.
• It is generally known that selection of films for packaging pharmaceutical products includes consideration of one or more criteria such as puncture resistance, cost, sealability, stiffness, strength, printability, durability, barrier properties, machinability, optical properties such as haze and gloss, flex-crack resistance and government approval for contact with pharmaceutical products. The type of polyethylene selected for use in the present invention and the thickness of the film (or layer for a multi-layer film) will depend on these considerations, as well as the size of the inner and outer bags and the estimated weight of the product.
• The outer bag is made from a plastic film that can be transparent or semi-transparent and can have one or more layers formed by well-known extrusion, co-extrusion and/or lamination processes. Preferably, at least one of the film layers is a structural layer and includes polyethylene, most preferably high or low density polyethylene. The structural layer(s) are intended to provide strength and impact resistance, to support the articles in the inner bag and to prevent the outer bag from rupturing. When the film includes multiple layers, it can have a gas barrier layer that prevents oxygen from passing through the film.
• The preferred construction for a multiple layer film includes a gas barrier layer disposed between two structural layers of polyethylene. The gas barrier layer can be made from ethylene/vinyl alcohol copolymer (EVOH) and polychlorotrifluoroethene (PCTFE or PTFCE). Other materials used in gas barrier layers of films for the food industry can also be used and are well known to one skilled in the art.
• The multi-layer films can also have one or more ethylene polymer-based adhesive layers disposed between the gas barrier layer and the outer structural layers. In addition, the outer bag structure can have an outer heat seal layer that includes an ethylene copolymer, such as ethylene vinyl acetate copolymer, for bonding the opposite sides of the outer bag together and for bonding the inner bag to the outer bag.
• The inner and outer bags are bonded together along the edges on at least three sides by a fusion bond. The fusion bond can be formed by ultrasonic welding of the layers to another at their registered edges, using a Branson ultrasonic welder (Branson Products, Inc., Danbury, Conn.) or other suitable ultrasonic welding tool. The bonded layers of the inner bag and the outer bag are joined at their edges on three sides to define an enclosed interior volume inside the inner bag for containment of a product article therein, e.g., a pharmaceutical and an intermediate space between the inner bag and the outer bag and an open side. The intermediate space can contain a desiccant for the absorption of moisture or other materials for absorbing oxygen, carbon dioxide or other gases that may be discharged by the product contained in the inner bag.
• After the inner and outer bags are formed with the first ends connected to the discharge port and the inner and outer bags defining an intermediate space, a desiccant or oxygen scavenging agent, such as sodium sulfite (Na₂SO₃), can be placed in the intermediate space. The inner and outer bags are then sealed on the second ends to isolate the intermediate space from the outside environment. However, the gas permeable wall of the inner bag allows gasses and water vapor to pass from the interior of the inner bag to the intermediate space. Thus, the intermediate space is isolated from gasses in the outside environment but is accessible to any gasses that may form in the interior of the inner bag.
• In one embodiment, the one or more inner bags are attached to one or more interior surfaces of the outer bag and extend lengthwise for a portion of or the entire length of the sidewall. The outer bag is formed from two moisture and gas impermeable plastic sheets that are sealed together along the perimetrical edges on at least three sides. The two plastic sheets have exterior surfaces and interior surfaces that face each other when the two sheets are sealed to form a bag. Prior to sealing the two sheets together, one or more sheets of permeable material are attached to the interior surface(s) of one or both of the sheets that form the outer bag to form one or more inner bags. Preferably, the sheets of permeable material are rectangular in shape and three of the edges are fused to the interior surface of the outer bag. A desiccant material is then added to the inner bag and the fourth side is sealed closed so that the desiccant material is enclosed between the interior surface of the outer bag and the sheet of permeable material.
• The length and width of the outer bag are selected to provide a bag with a desired capacity, as measured by either weight or volume. The construction of the two impermeable sheets that form the outer bag can vary depending on the capacity of the bag and the material that will be placed in the bag. For example, the sheets of the outer bag wall can be formed from different types of plastics and have one layer or multiple layers of different materials with the same or different thicknesses. The permeable sheet(s) that forms the inner bag(s) have lengths and widths that are selected based on the dimensions of the outer bag. The most important consideration in the design of the inner bags is that they provide moisture adsorption throughout the entire bag. In preferred embodiments, the length of the inner permeable sheet is from about 40% to 90% of the length of the outer bag, preferably from about 60% to 90% and the width of the inner sheet is from about 10% to 50% of the width of the outer bag, preferably from about 10% to 30%. When multiple inner sheets are attached to the interior surface(s) of the outer bag wall(s), the ratio of the area of the interior surface of the outer bag walls to the area of the inner sheets is between 10:1 and 2:1, most preferably about 4:1.
• In another embodiment, the inner bag is formed by two sheets with three or more sides and a perimetrical edge that is sealed to enclose the desiccant inside. One of the sides of the inner bag is attached to the interior surface of the outer bag and the inner bag extends outwardly from the attached edge into the interior of the outer bag. The side of the inner bag opposite the side that is attached to the interior wall of the outer bag can be attached to the opposite side of the outer bag by one or more members, such as a strap or elongated strip made of the plastic. The plastic can be any plastic that would be suitable for use in the outer bag, e.g., polyethylene, propylene, etc. The member is attached to the side of the inner bag and the opposite side of the outer bag so that there is a minimum amount of slack and the unattached side of the inner bag extends towards the middle of the outer bag. When the outer bag is filled with a material, the material contacts both sides of the inner bag and provides the maximum surface area for the desiccant to absorb any moisture in the material through the permeable sheets that for the inner bag.
• In a preferred embodiment, the inner bag is formed from two sheets of permeable material with a desiccant material inside. When the outer bag is formed, one of the side edges of the inner bag is disposed between the side edges of the outer bag as the side edges of the outer bag are sealed together. At the same time, the distal end(s) of one or more members is/are attached to the unattached side of the inner bag is/are sealed between the side edges on the opposite side of the outer bag. The member is taut so that the inner bag extends towards the center of the outer bag. In a more preferred embodiment, the side edge of an inner bag is sealed between the side edges of the outer bag on each side of the outer bag. The unattached sides of the two inner bags are attached by one or more taut members so that the inner bags extend inwardly.
• In another embodiment of the package system, the outer bag is three dimensional (“3-D”). Instead of being formed from two sheets of plastic, the outer bag is formed from four, five or six plastic sheets. In the four-sheet design, the outer bag has a front sheet, a rear sheet and two side sheets that have gussets or pleats. In a preferred embodiment of the four-side design, the front, rear and two side sheets are extruded in the form of a sleeve or tube and then pressed into the desired four-sided shape. The top and bottom edges of the side walls are gathered together and the bottom edges of the front and rear sheets are sealed. After the outer bag is filled with material, the top edges of the front and rear sheets are sealed to close the outer bag. When the outer bag is filled with material, the gussets/pleats unfold and increase the capacity of the outer bag. The five-sheet design is similar to the four-sheet design and includes a rectangular bottom sheet that is connected to the bottom of the front sheet, the rear sheet and the two side sheets. The five-sheet design can be made using a sleeve or tube as described above for the four-sheet design and the bottom sheet added or the front, rear and bottom sheets can be formed from a single sheet and folded prior to attaching the side sheets. The six-sheet design is similar to the five sheet design with a top sheet that connects to the top of the front sheet, the rear sheet and the two side sheets. The six-sheet design can be made using a sleeve or tube or a single sheet for three or four sides as described. In all of the 3-D designs, a discharge port can be located near the bottom of the outer bag and a fill port and/or a vent port can be located near the top of the outer bag.
• The inner bag(s) for the 3-D designs are similar to the inner bags for the outer bag pillow design with a side edge of one or more inner bags attached to the interior surface of the outer bag. Most preferably, the side edges of the inner bags are sealed between the edges formed when the front sheet and rear sheet are attached to the side sheets. One or more members can be used to connect two inner bags attached to diagonally opposing corners of the outer bag.
• The package system is now described with reference to the accompanying drawings,FIGS. 1-8, to further describe the features.FIG. 1 shows thepackage system10 that includes: aninner bag12, anouter bag14 with a compartment orintermediate space13 therebetween, adischarge port16 withcap18 and lockingring20 and ahandle22. Adesiccant24 is disposed in theintermediate space13 between the inner andouter bags12,14. Also shown is apressure equalizing port26 connected to afilter system28 with acap30 and lockingring32.
• FIG. 2 shows a side view of thepackage system10 in which the bottom of theinner bag12 is attached to the interior surface of theouter bag14 intermediate the first and second ends of theouter bag14. Preferably the point where the bottom of theinner bag12 attaches to the interior surface of theouter bag14 is at least 4 inches from thedischarge port16, more preferably 5 inches and most preferably 6 or more inches.FIG. 3 shows theinner bag12 with the bottom end attached to the interior of theouter bag14 and the other end open. In between the inner andouter bags12,14 is theintermediate space13 that receives the desiccant24 (FIG. 1) and any gas scavenging materials.FIG. 4 is similar toFIG. 3 and it shows an embodiment in which theinner bag12 formed by asection12aof gas permeable material, apanel12band awindow12c. Typically, the gas permeable material that forms theinner bag12 is non-transparent and prevents the contents from being viewed through the transparentouter bag14. Thepanel12band thewindow12care transparent and can be formed from materials that are not gas permeable. The methods for forming transparent openings in otherwise non-transparent plastic bags are well known to those skilled in the art.
• FIG. 5 shows thepressure equalizing port26 andfilter system28. Thefilter system28 can include one or more desiccants and or gas scavengingfilter materials34,36,38 that filter moisture and undesired gases to prevent them from entering the interior of theinner bag12. Thecap30 and lockingring32 as shown inFIGS. 6 and 7 are secured to thefilter system28 when thepackage system10 is transported or stored.FIG. 8 shows the handle that is attached to thepackage system10 opposite the discharge port16 (FIG. 1).
• FIGS. 9 and 10 show a second embodiment of thepackage system110 that includes: a firstouter plastic layer112 and a secondouter plastic layer114 disposed on either side of a gas and moisturepermeable layer115 to form afirst compartment111 and asecond compartment115. Ahandle122 is attached to the first end and adischarge port116 is located near the second end. One ormore desiccant packets124 are disposed in thesecond compartment113 between the gaspermeable layer115 and thesecond plastic layer114. Also shown is apressure equalizing port126 connected to afilter system128. The gaspermeable layer115 separates the desiccant124 from theproduct125 in thepackage system110 but allows moisture and gasses to pass through.
• FIG. 11 shows an embodiment similar to the second embodiment shown inFIGS. 9 and 10 wherein thebag system110 includes an overbag150. Theouter bag112 is placed inside the overbag150 for additional protection from gas and/or moisture contaminating the contents of theouter bag112 and for physical protection from damage that may occur during transportation. The overbag150 can be made from Mylar® or a polymer material such as LDPE or HDPE. Aseal152 at the top of the overbag150 isolates the contents from the exterior environment.
EXAMPLESExample 1
• A model test bag was produced by heat sealing a multi-layer bag, which included an interior layer made of Tyvek® that provides a vapor transmission wall disposed between two outer layers made of substantially gas and moisture impermeable HDPE. The top edges of the three layers were aligned in registration and the interior Tyvek® layer extended to a point intermediate the first and second ends of the two outer layers. The bottom and two side perimetrical edges of the outer layers of HDPE were sealed together to form a first compartment and the perimetrical edges on the bottom and two sides of the Tyvek® layer were sealed to the first outer HDPE layer to form a second compartment. One kg of the test salt was placed in the first compartment from the top end of the bag on one side of the Tyvek® layer and the desiccant material was placed on the other side (five ⅙ clay type desiccants from Desicare) of the Tyvek® layer in the second compartment. The perimetrical edges of the three layers on top side of the bag were sealed to close the system and isolate the product on one side of the Tyvek® wall from the desiccant on the other side so that the test salt was in contact with the vapor transmission wall. Model salts such as sodium acetate trihydrate, sodium chloride, potassium nitrate, dextrose and mannitol were placed in individual bags. The bags were monitored and after 90 days it was determined that the package system prevents the test salts from caking.
Example 2
• A lab study was carried out to demonstrate the ability of the package system to maintain materials in the free-flowing state. In addition, tests were performed to compare the package system to a prior art single use bag. The new package system bag was filled with 11.3 kg of free-flowing sodium chloride and the end cap, clamp and clip were placed on the bag. Another standard single use bag without the compartment for the desiccant (i.e., the Flowmor™ technology) was filled with same amount of free-flowing sodium chloride and sealed in the same manner. Both bags were placed side by side in a stability chamber at 40° C. and 75% RH. Both bags were tested after 32 days; the sodium chloride in the package system (see the photograph inFIG. 12) was free flowing and cake free. The material in the prior art bag (see the photograph inFIG. 13) was caked and not free-flowing.
Example 3
• Studies were carried out under high moisture conditions (40° C., 90% RH) on the bags, to study moisture infusion rates into the wall of the bag. A bag was placed in the stability chamber with a weighed eight units of desiccant (approximately 8 ounces); the cap and clip were placed on the bag and sealed. The desiccant, after 96 hours, gained 6.5 grams of water, which showed that the desiccant would be used up in 30 days at this water vapor transmission rate. The bag was then placed in a Mylar® bag (or any suitable bag with low moisture vapor transmission rate) and heat sealed. The vapor transmission rate was significantly increased and the test results showed an expected shelf life of over 400 days.
Example 4
• The purpose of this study was to test the ability of the bags to deliver a cohesive powder that has poor flow characteristics in small qualities. The first test material was L-Glutamine; 240.0 g of the material was added to the bag. The bag was sealed with an end cap, clamp, and clip. The powder was then delivered to a weighted container. The amount delivered was 238.0 g, giving a 99% recovery of the material. The study was repeated with a large quantity of material 9.1 kg of sodium chloride, recovered 9.1 kg near 100% recovery.
• FIG. 14 shows the third embodiment of thepackage system210 having anouter bag214 formed by twoplastic sheets218,220 (i.e., the pillow case design) and a plurality ofinner bags212. Theinner bags212 are formed from asheet213 of moisture permeable material that is placed on the interior surface222 of theouter bag214, filled withmoisture absorbing desiccant224 and then sealed along theperimetrical edge217. Theouter bag214 is formed from two moistureimpermeable plastic sheets218,220 that are sealed together along the side edges226,228 and thebottom edges230. Material is added to thepackaging system210 through the opening in the top and, after theouter bag214 is filled, the twoplastic sheets218,220 that form the front and rear of theouter bag214 are sealed closed.
• FIG. 15 shows the fourth embodiment of the package system310 having anouter bag314 formed by twoplastic sheets318,320 (i.e., the pillow case design) and twoinner bags311,312. Theinner bags311,312 are formed from two, preferably rectangular,sheets313,315 of moisture permeable material that are filled withmoisture absorbing desiccant324 and then sealed together along the perimetrical edges317. When theouter bag314 is formed, one of the side edges319 of eachinner bag312 is disposed between the side edges326,328 of the two moistureimpermeable plastic sheets318,320 and sealed together so that theside edge319 of theinner bag312 is attached to theinterior surface322 of theouter bag314. When twoinner bags312 are sealed to the opposing side edges316,328 of theouter bag314, theunattached sides321 of theinner bags312 can be tautly connected by one ormore members332 to keep theinner bags312 in the central portion of theouter bag314. After the side edges326,328 of theouter bag314 are sealed, the bottom edges330 are sealed together. Material is added to the packaging system310 through the opening in the top and, after theouter bag314 is filled, the twoplastic sheets318,320 that form the front and rear of theouter bag314 are sealed closed.
• FIG. 16 shows the fifth embodiment of thepackage system410 having anouter bag414 formed by five moisture impermeable plastic sheets—afront sheet418, abottom sheet419, arear sheet420 and a pair ofside sheets434,436 (i.e., the 3-D design)—and twoinner bags411,412. Theinner bags411,412 are formed from two, preferably rectangular,sheets413,415 of moisture permeable material that are filled withmoisture absorbing desiccant424 and then sealed together along the perimetrical edges417. When theouter bag414 is formed, one of the side edges419 of eachinner bag412 is disposed between theside edge426,428 of the front or rear moistureimpermeable plastic sheets418,420 and theedge435,437 of one of theside walls434,436 in diagonally opposing corners and sealed together so that theside edge419 of theinner bag412 is attached to theouter bag414. When twoinner bags412 are sealed to the opposing side edges426,428 of theouter bag414, theunattached sides421 of theinner bags412 can be tautly connected by one ormore members432 to keep theinner bags412 in the central portion of theouter bag414. After the side edges426,428 of the front andrear sheets418,420 are sealed to the side edges435,437side walls434,436, thebottom sheet419 is sealed to the bottom. Preferably, thefront sheet418,bottom sheet419 andrear sheet420 are formed from a single sheet of plastic that is folded to form the three sections.
• Theside walls434,436 can have folds orpleats438,440 extending from the top to the bottom that fold over to allow theouter bag414 to be in a collapsed configuration, with the front sheet contacting the rear sheet, when thepackaging system410 is being stored or transported. When theouter bag414 is filled, thepleats438,440 unfold and theouter bag414 expands to its maximum capacity. Material is added to thepackaging system410 through the opening in the top and, after theouter bag414 is filled, the twoplastic sheets418,420 that form the front and rear of theouter bag414 are sealed closed.
• FIG. 17 a side view of a sixth embodiment of thepackage system510 having anouter bag514 formed by six moisture impermeable plastic sheets—afront sheet518, abottom sheet519, arear sheet520, a pair ofside sheets534,536, and a top sheet542—and twoinner bags512 made of moisture permeable material with one side of each inner bag attached to the opposing corner edges of theouter bag514 and the opposingsides521 joined by a pair ofmembers532. The top sheet542 has afill port544 and thebottom sheet519 has adischarge port516. Eachport516,544 can be provided with a cap (seeitem18 inFIG. 1) to seal theport516,544 when theouter bag514 is filled with material. Thepackaging system510 shown inFIG. 17 is similar to thepackaging system410 shown inFIG. 16 with the addition of the top sheet540 and fill port5442. Theouter bag514 has twoinner bags512 filled withdesiccant524 and sealed around the edges517. One side edge of eachinner bag512 is attached to diagonally opposing corners of theouter bag514. The opposingsides521 of theinner bags512 are tautly connected by twomembers532 that keep theinner bags512 positioned in the central portion of theouter bag514.
• FIG. 18 shows the seventh embodiment of the package system610 having anouter bag614 formed by five moisture impermeable plastic sheets—afront sheet618, abottom sheet619,rear sheet620 and a pair ofside walls634,636 (i.e., the 3-D design)—and twoinner bags612. Theinner bags612 are formed from asheet613 of moisture permeable material that is placed on theinterior surface622 of theouter bag614, filled withmoisture absorbing desiccant624 and then sealed along theperimetrical edge617. Material is added to the packaging system610 through the opening in the top of theouter bag614 and, after theouter bag614 is filled, the twoplastic sheets618,620 that form the front and rear of theouter bag614 are sealed closed.
• FIG. 19 is a photograph of adrum248 with the third embodiment of thepackage system210 shown inFIG. 14 with material in theouter bag214 contacting theinner bags212.
• FIG. 20 is a photograph of thedrum248 with the third embodiment of thepackage system210 shown inFIG. 14 with aninner bag212 and anouter bag214 and no material in thepackaging system210.
• FIG. 21 shows the eighth embodiment of thepackage system710 having anouter bag714 formed by twoplastic sheets718,720 (i.e., the pillow case design) and an inner bag712. The inner bag712 is formed from asheet713 of moisture permeable material that is folded over and sealed along theperimetrical edge717 to form a pouch. After desiccant is added, the inner bag712 can be sealed along the top edge with the top edge of theouter bag714 so that the side walls of the inner bag712 are exposed to the interior of theouter bag714. In another embodiment, the inner bag712 can be sealed to the interior surface near the top of theouter bag714 on three sides, filled withmoisture absorbing desiccant724 and then sealed along theperimetrical edge717. Preferably, the inner bag712 is positioned lengthwise across the top of theouter bag714. Theouter bag714 is formed from two moistureimpermeable plastic sheets718,720 that are sealed together along the side edges and the bottom edges. Thebag714 can also be extruded as a sleeve or tube. However, the method used to form the bag is not a limitation of the present invention. Aport716 at the bottom of thebag714 can be used for filling or emptying thebag714. Material can also be added to thepackaging system710 through an opening in the top and, after theouter bag714 is filled, the twoplastic sheets718,720 that form the front and rear of theouter bag714 are sealed closed. Ahandle722 can be attached to the top of theouter bag714 to facilitate transporting thepackage system710.
Example 53-D Bags to be Used in Drum Configuration
• The bags currently in use are produced using a simple pillow design wherein the ends and bottom are sealed to produce a bag. This design limits the fill capacity and the ability to add a surround desiccant system. One embodiment of the bags of the present invention has a 3-D bag design with front and rear walls and pleated or accordion side walls that allow the bag to expand and fill will product similar to a square bag. The 3-D bag design for drums is a four wall square bag as shown inFIG. 18. Theouter bag614 is composed of LDPE and the perimetrical edges of a sheet ofTyvek®613 are welded to theinterior surface622 of theouter bag614 to form aninterior bag612, which is filled with adesiccant material614 before all of theedges617 are sealed to theinterior surface622 of theouter bag614. The configuration of theouter bag614 can be cube-shaped to fit a traditional round drum or it can have a rectangular block shape to fit a custom rectangular drum or box.
• Thus, while there have been described the preferred embodiments of the present invention, those skilled in the art will realize that other embodiments can be made without departing from the spirit of the invention, and it is intended to include all such further modifications and changes as come within the true scope of the claims set forth herein.

Claims (30)

We claim:

1. A package system for maintaining the physicochemical integrity of the contents of the package system, the package system comprising:

an outer bag comprising a sheet of a gas and/or moisture impermeable polymer material, the outer bag having an interior;

one or more inner bags, each inner bag comprising a sheet of a gas and/or moisture permeable material disposed in the interior of the outer bag, the sheet having a perimetrical edge, wherein the perimetrical edge is sealingly attached to the sheet of gas and/or moisture impermeable polymer material of the outer bag; and

at least one desiccant or gas scavenging material, wherein the desiccant material is disposed between each of the sheets of gas and/or moisture permeable material and the sheet of gas and/or moisture impermeable polymer material.

2. The package system according toclaim 1, wherein the outer bag comprises two sheets of gas and/or moisture impermeable polymer material, each sheet having a perimetrical edge extending along first and second sides and first and second ends, and wherein the perimetrical edges of the two sheets are sealed together at least on two sides and one end.

3. The package system according toclaim 1, wherein the sheet of a gas and/or moisture impermeable polymer material is formed as a tube having a first end and a second end, and wherein the second end is sealed to form the outer bag.

4. The package system according toclaim 1, wherein the ratio of the area of the sheet of gas and/or moisture impermeable polymer material to the area of the one or more sheets of gas and/or moisture permeable material is from about 10:1 to about 2:1.

5. The package system according toclaim 1, wherein the layer of gas and/or moisture permeable material is formed from a cloth or continuous and very fine fibers of randomly distributed and non-directional high-density polyethylene.

6. The package system according toclaim 1, wherein the gas and/or moisture impermeable polymer material of the outer bag comprises a low density or a high density polyethylene.

7. The package system according toclaim 1, wherein the gas impermeable material comprises at least three layers with a middle layer formed from a gas barrier material.

8. The package system according toclaim 7, wherein the gas barrier material of the middle layer is an ethylene/vinyl alcohol copolymer or polychlorotrifluoroethene.

9. A package system for maintaining the physicochemical integrity of the contents of the package system, the package system comprising:

an outer bag comprising a perimetrical side wall formed from a gas and/or moisture impermeable polymer material, the perimetrical side wall comprising in order a front sheet, a first side sheet, a rear sheet and a second side sheet, the outer bag having an interior, a first end and a second end;

one or more inner bags, each inner bag comprising a sheet of a gas and/or moisture permeable material disposed in the interior of the outer bag, the sheet having a perimetrical edge, wherein the perimetrical edge is sealingly attached to the front or rear sheet of gas and/or moisture impermeable polymer material; and

at least one desiccant or gas scavenging material, wherein the desiccant material is disposed between the sheet of gas and/or moisture permeable material and the sheet of gas and/or moisture impermeable polymer material.

10. The package system according toclaim 9, wherein the first and second side sheets have one or more pleats.

11. The package system according toclaim 9, wherein the second end of the outer bag is sealing closed by a bottom sheet formed from a gas and/or moisture permeable material.

12. The package system according toclaim 9, wherein the second end of the outer bag has a discharge port.

13. The package system according toclaim 9, wherein the first end of the outer bag is sealing closed by a top sheet formed from a gas and/or moisture permeable material.

14. The package system according toclaim 9, wherein the first end of the outer bag has a fill port.

15. The package system according toclaim 9, wherein the ratio of the area of the perimetrical side wall of gas and/or moisture impermeable polymer material to the area of the sheets of gas and/or moisture permeable material is from about 10:1 to about 2:1.

16. The package system according toclaim 9, wherein the layer of gas and/or moisture permeable material is formed from a cloth or continuous and very fine fibers of randomly distributed and non-directional high-density polyethylene.

17. The package system according toclaim 9, wherein the gas and/or moisture impermeable polymer material of the outer bag comprises a low density or a high density polyethylene.

18. The package system according toclaim 9, wherein the gas impermeable material comprises at least three layers with a middle layer formed from a gas barrier material.

19. The package system according toclaim 18, wherein the gas barrier material of the middle layer is an ethylene/vinyl alcohol copolymer or polychlorotrifluoroethene.

20. A package system for maintaining the physicochemical integrity of the contents of the package system, the package system comprising:

an outer bag comprising a perimetrical side wall formed from a gas and/or moisture impermeable polymer material, the perimetrical side wall comprising in order a front sheet, a first side sheet, a rear sheet and a second side sheet, wherein the front, rear and side sheets defining two pairs of diagonally opposed corners and wherein the outer bag having an interior, a first end and a second end;

one or more inner bags disposed in the interior of the outer bag, each inner bag comprising two sheets formed from a gas and/or moisture permeable material and having a perimetrical edge, wherein the perimetrical edges of the sheets are sealed together to form one of the one or more inner bags, each inner bag having an enclosed space and first and second side edges, wherein one side edge of a first inner bag is attached to one of the diagonally opposed corners; and

at least one desiccant or gas scavenging material, wherein the desiccant material is disposed in the enclosed space of each of the inner bags.

21. The package system according toclaim 20, wherein the first side edge of a second inner bag is attached to the corner diagonally opposite the first inner bag, and wherein at least one member connects the second side edges of the first and second inner bags.

22. The package system according toclaim 20, wherein the first and second side sheets have one or more pleats.

23. The package system according toclaim 20, wherein each of the first and second ends of the outer bag is sealing closed by a top sheet and bottom sheet, respectively, formed from a gas and/or moisture permeable material.

24. The package system according toclaim 20, wherein the first end of the outer bag has a fill port and the second end has a discharge port.

25. The package system according toclaim 20, wherein each of the fill port and the discharge port has a removable cap for closing the fill port or discharge port and sealingly isolating the interior of the outer bag from the exterior environment.

26. The package system according toclaim 25, wherein the ratio of the area of the perimetrical side wall of gas and/or moisture impermeable polymer material to the area of the sheets of gas and/or moisture permeable material of the one or more inner bags is from about 10:1 to about 2:1.

27. The package system according toclaim 20, wherein the layer of gas and/or moisture permeable material is formed from a cloth or continuous and very fine fibers of randomly distributed and non-directional high-density polyethylene.

28. The package system according toclaim 20, wherein the gas and/or moisture impermeable material of the outer bag comprises a low density or a high density polyethylene.

29. The package system according toclaim 20, wherein the gas impermeable material comprises at least three layers with a middle layer formed from a gas barrier material.

30. The package system according toclaim 29, wherein the gas barrier material of the middle layer is an ethylene/vinyl alcohol copolymer or polychlorotrifluoroethene.

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