Patent Publication Number: US-2021188514-A1

Title: Recyclable flexible package with valve for oxygen sensitive products and methods of making the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This utility application claims the benefit under 35 U.S.C. § 119(e) of Provisional Application Ser. No. 62/951,319 filed on Dec. 20, 2019, entitled Recyclable Flexible Package with Valve for Oxygen Sensitive Products and Methods of Making the Same. The entire disclosure of the provisional application is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of Invention 
     This invention relates generally to flexible packages, and more particularly to flexible packages with valves for oxygen sensitive products which can be recycled without having to separate the components making up the packages and methods for making such packages. 
     Description of Related Art 
     Flexible packages formed of sheet materials have been used for many years and have wide acceptance for holding various products, e.g., roasted coffee and other foodstuffs. Such packages are typically constructed so that they form a high barrier to oxygen to protect the contents of such packages from the ravages of oxygen. For example, high barrier packages for products, such as coffee, are typically composed of layers of dissimilar materials such as a combination of polyester, aluminum foil or a vacuum deposited aluminum coating, and polyethylene. Moreover, such packages commonly include a one-way degassing valve to enable gases produced by the coffee within the bag from exiting the bag, through the valve, while preventing oxygen from entering the bag through the valve. While his type of package construction performs very well for coffee preservation it leaves much to be desired from the standpoint of ecology. In this regard, such multilayer mixed plastic and metal composition flexible packages are currently unable to be recycled economically because the individual components making up the packages cannot be separated from one another. 
     Accordingly, a need exists for a high oxygen barrier flexible package with a valve which can be readily recycled. The subject invention addresses that need by providing a flexible package having a degassing valve which is comprised of substantially one thermoplastic material. This allows for easier recycling of the package since there is no need to separate its individual layers and components. 
     Thus, a need exists for a flexible package laminated film exhibiting a higher oxygen barrier value than the sum of the barrier values of its various component layers. The subject invention addresses that need. 
     SUMMARY OF THE INVENTION 
     One aspect of this invention is a recyclable flexible package configured to be located within an ambient atmosphere. The recyclable flexible package comprises an engagement enhancing liquid, a valve, and a hollow body. The valve is configured to be normally in a closed state, but openable to an open state. The valve consists essentially of a first type of thermoplastic material and comprises a movable valve member and a hollow housing including a portion forming a valve seat. The movable valve member is in engagement with the valve seat when the valve is in the closed state. The engagement liquid is interposed between the movable valve member and the valve seat to assist in the engagement of the movable valve with the valve seat. The hollow body is resistant to atmospheric oxygen transmission through it and is formed of a laminated film of flexible material defining an interior chamber configured for holding a product therein. The valve is mounted on the hollow body interposed between the hollow interior and the ambient atmosphere and configured to isolate the hollow interior from the ambient atmosphere when the valve is in the closed state and to enable a gas within the interior chamber to exit through the valve to the ambient atmosphere when the valve is in the open state. The laminated film comprises at least one layer of the first type of thermoplastic material. The first type of thermoplastic material constitutes at least 95% by weight of the recyclable flexible package, whereupon the recyclable flexible package is suitable for recycling without requiring separation of the materials thereof. 
     In accordance with one preferred aspect of the recyclable package of this invention the first material is polypropylene. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film comprises a first layer of oriented polypropylene. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film comprises a layer of non-oriented polypropylene. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film additionally comprises a layer of polyvinyl alcohol. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film additionally comprises a layer of polyester-urethane adhesive. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film additionally comprises a second layer of oriented polypropylene. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film additionally comprises a second layer of polyester-urethane adhesive. 
     In accordance with another preferred aspect of the recyclable package of this invention the laminated film additionally comprises a vacuum deposited aluminum coating. 
     In accordance with another preferred aspect of the recyclable package of this invention the polyvinyl alcohol layer is disposed over the first layer of oriented polypropylene, the polyester-urethane-adhesive layer is disposed over the polyvinyl alcohol layer, the second layer of oriented polypropylene is disposed over the polyester-urethane-adhesive layer, the second layer of polyester-urethane adhesive is disposed over the second layer of oriented polypropylene, and the layer of non-oriented polypropylene is disposed over the second layer of polyester-urethane adhesive. 
     In accordance with another preferred aspect of the recyclable package of this invention the first layer of oriented polypropylene is approximately 18-microns thick, the polyvinyl alcohol layer is approximately 0.5 microns thick, the polyester-urethane-adhesive layer is approximately 1.9 microns thick, the second layer of oriented polypropylene is approximately 18-microns thick, the second layer of polyester-urethane adhesive is approximately 1.9 microns thick, and the layer of non-oriented polypropylene is approximately 76 microns thick. 
     In accordance with another preferred aspect of the recyclable package of this invention the recyclable flexible package additionally comprises a layer of printing ink interposed between the polyvinyl alcohol layer and the layer of polyester-urethane-adhesive. 
     In accordance with another preferred aspect of the recyclable package of this invention the recyclable flexible package additionally comprises a vacuum deposited aluminum coating interposed between the second layer of oriented polypropylene and the second layer of polyester-urethane adhesive. 
     In accordance with another preferred aspect of the recyclable package of this invention the vacuum deposited aluminum coating is approximately 1 micron thick. 
     In accordance with another preferred aspect of the recyclable package of this invention the recyclable flexible package additionally comprises a layer of a peelable seal material on a portion of the laminated film. The portion of the laminated film forms an inner surface of the hollow body and also forms a mouth of the flexible package. 
     In accordance with another preferred aspect of the recyclable package of this invention the layer of peelable seal is approximately 5 microns thick. 
     In accordance with another preferred aspect of the recyclable package of this invention the recyclable flexible package additionally comprises a filter. 
     In accordance with another preferred aspect of the recyclable package of this invention the portion of the valve forming the valve seat comprises a base, and the movable valve member comprises a flexible septum. 
     In accordance with another preferred aspect of the recyclable package of this invention the hollow housing comprises a cap. 
     In accordance with another preferred aspect of the recyclable package of this invention the engagement liquid comprises polydimethylsiloxane. 
     Another aspect of this invention is a method of making a recyclable flexible package. That method entails forming a hollow body resistant to atmospheric oxygen transmission therethrough of a laminated flexible film defining an interior chamber configured for holding a product therein. The laminated film comprises a layer of oriented polypropylene material, a layer of non-oriented polypropylene material, a layer of polyvinyl alcohol material, and a layer of polyester-urethane adhesive material. A valve is mounted on the hollow body so that the valve is interposed between the hollow interior and ambient atmosphere. The valve comprises components formed of polypropylene material and an engagement liquid. The polypropylene material of the body and the valve constitutes at least 95% by weight of the recyclable flexible package, whereupon the recyclable flexible package is suitable for recycling without requiring separation of the materials thereof. 
     In accordance with one preferred aspect of the method of this invention, the laminated film additionally comprises a second layer of oriented polypropylene material and a second layer of polyester-urethane adhesive material. 
     In accordance with another preferred aspect of the method of this invention, the polyvinyl alcohol material layer is disposed over the oriented polypropylene material layer, the polyester-urethane-adhesive material layer is disposed over the polyvinyl alcohol material layer, the second layer of oriented polypropylene material is disposed over the polyester-urethane-adhesive material layer, the second layer of polyester-urethane adhesive material is disposed over the second layer of oriented polypropylene material, and the layer of non-oriented polypropylene material is disposed over the second layer of polyester-urethane adhesive material. 
     In accordance with another preferred aspect of the method of this invention, a vacuum deposited aluminum coating is interposed between the second layer of oriented polypropylene material and the second layer of polyester-urethane adhesive material. 
     In accordance with another preferred aspect of the method of this invention, a layer of printing ink is interposed between the polyvinyl alcohol material layer and the polyester-urethane-adhesive material layer. 
     In accordance with another preferred aspect of the method of this invention, a layer of a peelable seal material is provided on a portion of the laminated film. The portion of the laminated film forms an inner surface of the hollow body and also forms a mouth of the flexible package. 
     In accordance with another preferred aspect of the method of this invention, the layer of oriented polypropylene material is approximately 18-microns thick, the polyvinyl alcohol material layer is approximately 0.5 microns thick, the polyester-urethane-adhesive material layer is approximately 1.9 microns thick, the second layer of oriented polypropylene material is approximately 18-microns thick, the second layer of polyester-urethane adhesive material is approximately 1.9 microns thick, and the layer of non-oriented polypropylene material is approximately 76 microns thick. 
     In accordance with another preferred aspect of the method of this invention, a vacuum deposited aluminum coating is interposed between the second layer of oriented polypropylene material and the second layer of polyester-urethane adhesive material. The vacuum deposited aluminum coating is approximately 1 micron thick. 
     In accordance with another preferred aspect of the method of this invention, a layer of a peelable seal material is provided on a portion of the laminated film. The portion of the laminated film forms an inner surface of the hollow body and also forms a mouth of the flexible package. The layer of peelable seal material is approximately 5 microns thick. 
     In accordance with another preferred aspect of the method of this invention, the oriented polypropylene material layer is coated with polyvinyl alcohol to form the polyvinyl alcohol material layer. Then the layer of polyester-urethane adhesive is applied thereover to form the polyester-urethane adhesive layer, after which additional oriented polypropylene material is applied to the polyester-urethane adhesive layer by the application of heat and pressure to form the second oriented polypropylene material layer, after which additional polyester-urethane adhesive material is applied to an exposed surface of the second oriented polypropylene material layer to form the second polyester-urethane adhesive material layer, after which non-oriented polypropylene material is applied to the second polyester-urethane adhesive material layer to form the non-oriented polypropylene material layer and complete the formation of the laminated film. 
     In accordance with another preferred aspect of the method of this invention, the method additionally comprises additionally winding the laminated film onto a roll or coil. 
     In accordance with another preferred aspect of the method of this invention, the method additionally comprises allowing the laminated film on the roll or coil to cure for a period of time, and then converting it into the recyclable flexible package. 
     In accordance with another preferred aspect of the method of this invention, the method additionally comprises applying printing ink over the polyvinyl alcohol material layer before the layer of polyester-urethane adhesive is applied thereover. 
     In accordance with another preferred aspect of the method of this invention, the method additionally comprises applying a vacuum deposited aluminum coating between the second layer of oriented polypropylene material and the second layer of polyester-urethane adhesive material. 
    
    
     
       DESCRIPTION OF THE DRAWING 
       The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein: 
         FIG. 1  is an isometric view of one exemplary recyclable flexible package constructed in accordance with this invention; 
         FIG. 2  is a cross-section view, taken along line  2 - 2  and showing the construction of the degassing valve forming a portion of the recyclable package of  FIG. 2 ; 
         FIG. 3  is a highly enlarged, but not to scale, cross sectional view taken along line  3 - 3  of  FIG. 1  showing the construction of the laminated film making up the body of the recyclable flexible package shown in  FIG. 1 ; 
         FIG. 4  is a highly enlarged, but not to scale, cross sectional view taken along line  4 - 4  of  FIG. 1  showing the peelable mouth of the recyclable flexible package shown in  FIG. 1 ; and 
         FIG. 5  is a cross-sectional view, similar to  FIG. 3 , but showing an alternative embodiment of a laminated film making up the body of the recyclable flexible package shown in  FIG. 1 ; 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown in  FIG. 1  one exemplary embodiment of a recyclable flexible package  20  constructed in accordance with this invention. The flexible package  20  is configured to include an interior chamber for holding an oxygen sensitive product, e.g., coffee beans, ground coffee, etc., to preserve that product by blocking atmospheric oxygen transmission through the walls of the package. The exemplary package  20  is in the form of a gusseted bag  22  formed of a laminated film  10  ( FIGS. 3 and 4 ) which forms a barrier to the passage of oxygen from the ambient atmosphere into the interior chamber of the bag. A pressure-equalizing, one-way degassing valve  24  is mounted on the bag&#39;s front wall to enable gases produced by the coffee within the bag to exit the bag through the valve  24 . 
     It should be noted at this point that while the bag  22  is shown in the form of a gusseted bag, it may take other constructions and still be within the scope of this invention. By way of example, but not limitation, the bag portion of a package constructed in accordance with this invention may be in the form of a so-called “pillow bag”, a “stand-up pouch” or any other type or style of flexible package. What is important is the thermoplastic material making up the package being of the same type so that the package needn&#39;t be separated for recycling. To that end, as will be described in detail later the bag  22  is formed of a laminated film material which by weight is essentially one type of thermoplastic material, e.g., polyethylene, with the valve being formed of the same type of thermoplastic material. 
     As mentioned earlier, the exemplary gusseted bag  22  is formed of a flexible laminated film  10 . In particular it basically comprises a front wall or panel  22 A, a rear wall or panel  22 B, a pair of identical opposed gusseted side walls or panels  22 C, a top end portion  22 D, and a bottom end portion  22 E. The top end portion of the bag terminates in a top marginal edge, while the bottom end portion terminates in a bottom marginal edge. The degassing valve  24  is mounted in the front panel  22 A, although it can be located in the rear panel as well, and is in communication with the interior of the bag, which is in the form of a hollow chamber  12  ( FIG. 2 ) for holding the coffee  14  therein. The valve  24  enables gasses which may be produced by the material(s) (e.g., coffee  14 ) contained within the chamber  12  after the bag is hermetically sealed to vent to the ambient air, without air gaining ingress to the bag&#39;s chamber. 
     In the exemplary embodiment of the package  20  the front panel  22 A, rear panel  22 B, and the two gusseted sides  22 C of the bag are all integral portions of a single sheet or web of the flexible film  10  which has been folded and seamed to form a tubular body. The package has a peelable mouth formed by a line  22 F of conventional peelable seal material located on portions of the inner surface of the walls of the bag adjacent, e.g., slightly below, its top marginal edge and extending across the width of the front and rear panels and the interposed gusseted sides as best seen in  FIGS. 1 and 4 . The peelable seal line  22 F enables the walls of the bag to be readily peeled apart to open the mouth to provide access to the product held within the interior of the bag. The package  20  is arranged to be initially hermetically sealed closed along the peelable seal line  22 F after it has been filled and vacuumized. 
     The lower or bottom end of the bag  22  is sealed closed along a transverse, permanent seam line (not shown) closely adjacent the bottom edge  36 . The permanent seam line is formed using any conventional sealing technique. When the bag  20  is filled, vacuumized, and sealed its particulate contents, e.g., coffee  14 , will be kept isolated from the ambient air by the material barrier properties of the laminated film making up the bag  22 . 
     The degassing valve  24  is best seen in  FIG. 2  and is constructed similar to the valve of U.S. Pat. No. 5,893,461, whose disclosure is specifically incorporated herein, and basically comprises a cap  26 , a base  28 , a movable valve member or septum  30 , and a filter member  32 . The cap and base when connected together form the housing of the valve. The septum  30  is in the form of a flexible disk which is located within the housing. The cap  26  is a generally cylindrical member having a planar circular top wall  26 A and a circular slightly conical side wall  26 B terminating at its bottom in an under-cut annular groove  26 C. The base member  28  is a generally cup-shaped member having a planar circular bottom wall  28 A and a circular sidewall  28 B terminating at its top in an annular flange  28 C. The bottom wall  28 A includes a central opening or hole  28 D having an annular flange extending thereabout and projecting up from the interior surface of the bottom wall  28 A. The annular flange is under-cut on its exterior surface to be received in and mate with, e.g., snap-fit in, the under-cut groove  26 C in the cap  26  to connect the cap to the base and thereby complete the valve&#39;s housing. 
     The entrance to the central opening or hole  28 D in the base  28  is located at the bottom of the bottom wall  28 A and is enlarged to form a ledge on which the filter member  32  is disposed and secured, e.g., glued. The top surface of the base surrounding the central opening or hole  28 D is planar and forms the valve seat  28 E of the valve. A thin layer of polydimethylsiloxane (silicone oil)  34  is interposed between the disk  30  and the valve seat  28 E. As is known, the presence of the oil  34  interposed between the septum and the valve seat serves an engagement enhancing liquid which forms an elastic bond to enhance the engagement of the septum on the valve seat when the valve is in its normally closed state. 
     The flange  28 C of the base serves as the means to secure the valve  24  to the front panel or wall  22 A of the package  20 . To that end, the valve&#39;s flange  28 C is welded or heat sealed about its entire top surface to the inner surface of the front wall  22 A. A pair of small apertures or holes  36  is provided in the front wall of the bag within the bounds of the seal line extending around the flange  26 C. Those apertures are in fluid communication with the interior of the valve located above the septum  30 . The valve is configured to be in a normally closed state, whereupon the underside of the septum  30  contiguous with its outer periphery is in engagement with the valve seat  28 E via the interposed oil  34  to thereby close off the opening or hole  28 D and thus isolate the interior of the bag from the ambient atmosphere. 
     As will be appreciated by those skilled in the art, when the pressure in the interior chamber  12  of the bag is higher than the pressure of the ambient air surrounding the package, as may occur when the coffee within the package degasses, the higher internal pressure will break the elastic bond between the valve seat, the oil  34 , and the septum  30 , allowing the gas within the package to escape in the direction of arrows shown in  FIG. 2  out of the valve and through the holes  36  in the front panel of the bag. 
     In accordance with a preferred embodiment of this invention the cap  26  and base  28  are injection molded of polypropylene, the disk  30  is stamped from a sheet of polypropylene and the filter member  32  comprises a circular disk of non-woven polypropylene. As such one exemplary valve  24  constructed in accordance with this invention is composed of approximately 1,000 milligrams of polypropylene and 4 milligrams of silicone oil, so that the valve constitutes approximately 99.6% polypropylene by weight. 
     Turning now to  FIG. 3  the details of one exemplary laminated film  10  constructed in accordance with this invention to produce the bag  22  will now be described. To that end, the laminated film  10  is constructed and produced as follows. A film layer  10 A of oriented polypropylene having a thickness of approximately 18 microns is first coated with a layer  10 B of polyvinyl alcohol having a thickness of approximately 0.5 microns. Next, an optional layer  10 C of printing ink(s) is/are applied over the polyvinyl alcohol to decorate the package. Next, a layer  10 D of polyester-urethane adhesive having a thickness of approximately 1.9 microns is applied over the printing ink layer, if that layer is used. If the laminated film does not include a layer of printing ink(s), the polyester-urethane adhesive layer  10 D is applied over the polyvinyl alcohol layer  10 B. Next a second layer  10 E of oriented polypropylene having a thickness of approximately 18 microns is applied over the polyester-urethane adhesive layer  10 D, by application of heat and pressure. Next, an optional coating  10 F of aluminum is vacuum deposited on the second layer  10 E of oriented polypropylene. The aluminum coating has a thickness of approximately 1 micron or less and is used to provide a light barrier, oxygen barrier, moisture barrier and static dissipation for the laminated film. Next a second layer  10 G of polyester-urethane adhesive having a thickness of approximately 1.9 microns is applied to the exposed side of the aluminum coating  10 F, if such a coating is used. If, the laminated film doesn&#39;t include the optional aluminum coating, the second layer  10 G of polyester-urethane adhesive is applied to the second layer  10 E of oriented polypropylene. A layer  10 H of non-oriented polypropylene having a thickness of approximately 76 microns is applied over the second layer  10 G of polyester-urethane adhesive to complete the laminated film, which is then wound onto a roll or coil. 
     The coil of laminated film can then be allowed to cure for 5-7 days and then converted into the exemplary gusseted package  20  or any other type of flexible package, with the non-oriented polypropylene of layer  10 H forming the inner surface of the bag  22 . As mentioned above, the inside of the bag may include a peelable seal material at its mouth to enable the mouth to be peeled open. The peelable seal material is in the form of a coating applied in a line  22 F to the area of the laminated film which will form the mouth of the bag. The peelable coating can be made of a variety of known peelable coating materials, and is only applied to about 10% of the exposed side of the oriented polypropylene layer, is approximately 5 microns thick in the coated area and can be applied to the non-oriented polypropylene layer  10 H just prior to the formation of the bag, or during the formation of the bag. 
     In  FIG. 5  there is shown an alternative laminated film  10 ′ constructed in accordance with this invention. The film  10 ′ is constructed similarly to the film  10 , but does not include the optional printing ink layer  10 C and the optional aluminum coating layer  10 F. 
     Flexible packages constructed in accordance with this invention will constitute at least 95% by weight of the thermoplastic, e.g., polypropylene, so that those packages can be recycled without necessitating separating their various plies or layers of the bags or separating the valves from the bags. Moreover, the flexible packages of this invention will still provide excellent resistant to the passage of oxygen therethrough. In this regard, barrier to oxygen of the composite material making up the laminated film of the package this invention has been measured in a laboratory per ASTM D3985 at 0.02 cc/(100 square inches-24 hours) at 23 degrees C. and 0% RH. 
     It must be pointed out at this juncture that the exemplary laminated films as described above are mere some examples of laminated films that can be used to make recyclable flexible packages in accordance with this invention, Thus, such films may make use of more or less layers or plies of various types of materials so long as the laminated film is composed of at least 95% by weight of a single type of thermoplastic material. Moreover, any type or construction of a degassing valve can be used, and need not be constructed like the exemplary valve  24  described above so long as the valve is formed of the same type of thermoplastic as that used in the laminated film and whereby the thermoplastic material constitutes at least 95% by weight of the recyclable flexible package. 
     While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.