VACUUM STORAGE BAG

BACKGROUND OF THE INVENTION

[0001] Flexible plastic bags are used for a variety of purposes including storing food items, either temporarily in the case of packaging snacks or long term as in the case of freezer storage. Plastic bags of this style are typically made from one or more sheets of flexible plastic material arranged to provide an interior volume that is accessible through an opening. To close the opening after insertion of food items, interlocking closure strips may be provided about the rim of the opening. Likewise, the plastic material comprising the rim may be heat sealed together or glued together with a pressure sensitive adhesive to more permanently seal the opening. [0002] One common problem that occurs with such bags is that after the opening has been sealed, latent air may remain trapped in the interior volume. In addition to undesirably increasing the overall size of the bag, the trapped air can cause spoilation or dehydration of the stored food items. Further, in freezer storage applications, the trapped air can contribute to freezer burn of the stored food items.

BRIEF SUMMARY OF THE INVENTION

[0003] The invention provides a vacuum storage bag made with flexible plastic sidewalls of an air permeable material or materials. To improve manufacturability of the bag and provide adequate toughness for use in vacuum applications, the sidewall materials can include multiple plies or layers of air permeable materials including a heat sealable innermost layer and a tougher and stronger, outwardly situated, gas permeable layer. An example of a material sufficient for the heat sealable inner layer includes low density polyethylene and an example of a material suitable for the stronger gas permeable layer includes high density polyethylene. Though such materials are not truly gas impermeable, they provide sufficient resistance to air penetration to adequately maintain a vacuum state acceptable for food storage. [0004] When the two sidewalls of the storage bag are overlaid and arranged to provide an interior volume, the heat sealable inner layers of the sidewalls can be

[0005] joined together by a heat sealing operation to form the closed edges of the bag. The stronger layer, which may not be as susceptible to forming heat seals, provides sufficient toughness to resist destructive deformation or stretching of the bag while under vacuum. For example, in absence of the stronger layer, stretching of the sidewalls about stored food items during evacuation may cause the bag to develop small holes or tears thereby compromising the vacuum.

[0006] An advantage of the inventive vacuum storage bag is that manufacture of the bag is facilitated by having heat sealable inner layers as part of the sidewall. Another advantage is that the stronger, outer layer provides sufficient toughness to preclude destructive deformation of the sidewalls and resist the ingress of air into the interior volume. Another advantage is that the invention provides a vacuum storage bag that can be made from relatively low cost, gas permeable materials. These and other features and advantages of the invention will be apparent from the foregoing drawings and detailed description of the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a perspective view of a vacuum storage bag designed in accordance with the teachings of the invention, the bag having flexible sidewalls of an air permeable plastic material.

[0008] Figure 2 is a cross-sectional view taken along line A-A of the vacuum storage bag of Figure 1 showing the plies or layers of the flexible sidewalls including a heat sealable inner layer and a stronger, outwardly situated, air permeable layer.

[0009] Figure 3 is another cross-sectional view taken along line A-A of the vacuum storage bag of Figure 1 showing another possible arrangement of the layers of the flexible sidewalls.

[0010] Figure 4 is another cross-sectional view taken along line A-A of the vacuum storage bag of Figure 1 showing another possible arrangement of the layers of the flexible sidewalls.

[0011] Figure 5 is a front perspective view of a one-way valve element for attachment to the vacuum storage bag of Figure 1.

[0012] Figure 6 is a rear perspective view of the one-way valve element of Figure

5.

[0013] Figure 7 is a cross-sectional view taken along line B-B of the one-way valve element of Figure 5.

[0014] Figure 8 is an exploded view of another embodiment of a one-way valve element for attachment to the vacuum storage bag of Figure 1.

[0015] Figure 9 is an exploded view of another embodiment of a one-way valve element for attachment to the vacuum storage bag of Figure 1.

[0016] Figure 10 is a cross-sectional view taken along line C-C of Figure 1 through the vacuum storage bag having a textured portion and an embodiment of the one-way valve element engaging a nozzle of a vacuum source, the sidewalls of the bag collapsed together and an air flow path indicated.

[0017] Figure 11 is a detailed view as taken about circle D of Figure 1 of an embodiment of a textured portion on an inner surface of a sidewall of the flexible plastic bag.

[0018] Figure 12 is a detailed view as taken about circle D of Figure 1 of another embodiment of a textured portion formed as a plurality of grooves disposed into an inner surface of the sidewall.

[0019] Figure 13 is a detailed view as taken about circle D of Figure 1 of another embodiment of a textured portion formed as a plurality of protuberances disposed on an inner surface of a sidewall.

[0020] Figure 14 is a perspective view of another embodiment of the flexible bag having a textured portion along a side edge and a one-way valve element.

[0021] Figure 15 is a perspective view of another embodiment of the flexible bag having a textured portion provided with a T-shape and a one-way valve element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Now referring to the drawings, wherein like reference numbers refer to like features, there is illustrated in FIG. 1 a vacuum storage bag 100 made of flexible materials that can be used for the vacuum storage of food items. In the illustrated embodiment, the storage bag 100 includes a first sidewall 102 and an opposing second sidewall 104 overlaying and joined to the first sidewall so as to provide an interior volume 106. Accordingly, each of the first and second sidewalls 102, 104 has a

respective inner surface 108, 109. To join the first and second sidewalls 102, 104 together, heat seals are formed along a first side edge 110, a parallel second side edge 112, and a closed bottom edge 114 that extends between the first and second side edges 102, 104. To access the interior volume 106, an opening 116 is provided by allowing the portions of the first and second sidewalls 102, 104 corresponding to the top edge opposite the closed bottom edge 114 to remain unjoined. Due to the four orthogonal sides, the storage bag 100 has a generally rectangular shape. However, in other embodiments, the storage bag can have any other suitable shape or size. [0023] To releasably close the opening 116 after insertion of an item for storage, there can be attached to the first and second sidewalls 102, 104 and parallel to the open top edge respective first and second fastening strips 120, 122. The first and second fastening strips 120, 122 can be formed from extruded, flexible thermoplastic and extend between the first and second side edges 110, 112. As will be appreciated by those of skill in the art, the first and second fastening strips 120, 122 can engage to form a seal which closes the normally open top edge 116. Of course, in other embodiments or in combination with the interlocking strips, other methods such as the use of pressure sensitive or cold seal adhesives such as those disclosed in U.S. Patent No. 6,149,304, herein incorporated by reference in its entirety, heat-sealing, or cling can be employed to seal the opening 116.

[0024] To evacuate air trapped in the interior volume 106 after sealing closed the opening 116, in the illustrated embodiment, a one-way valve element 130 is attached to the first sidewall 102 and communicates with the interior volume. The one-way valve element 130 is capable of opening to allow entrapped air to escape from the enclosed interior volume 106 and of closing to prevent the ingress of environmental air. Evacuation through the valve element 130 can be accomplished by squeezing the first and second sidewalls together or by using a vacuum source. As explained in more detail below, to promote evacuation through the one-way valve element, an inner surface of at least one sidewall can include a textured portion to provide air flow paths toward the valve element. While the valve element and the textured portion provide one manner of evacuating air from the interior volume, in other embodiments,

other evacuation methods can be utilized that, for example, operate with and during the sealing of the opening.

[0025] In accordance with an aspect of the invention, to improve manufacturability and durability of the storage bag, the flexible sidewalls can be made from a gas permeable, multilayered material. More specifically, as illustrated in FIG. 2, the sidewalls 102, 104 can be made from a multilayered web or sheet that includes at least a first, innermost layer 140 of heat sealable material and a second, outwardly situated layer 142 of a stronger, gas permeable material. For example, the inner heat sealable layer can be comprised of air permeable low density polyethylene (LDPE) or of linear low density polyethylene (LLDPE) while the tougher outwardly disposed layer can be comprised of air permeable high density polyethylene (HDPE). [0026] Characteristically, low density polyethylene has a lower density, lower tensile strength and lower melt temperature but is more flexible and pliable than high density polyethylene. For example, low density polyethylene can have a density of between about 0.91 grams per cubic centimeter (g/cc) to about 0.94 g/cc, a melt temperature of about 120 ⁰ C, and a tensile strength of about 7670 PSI in the machine direction and 6670 PSI in the cross-direction. High density polyethylene can have a density of between about 0.94 g/cc to about 0.96 g/cc, a melt temperature of about 135 ⁰ C, and a tensile strength of about 11,999 PSI in the machine direction and 9600 PSI in cross-direction.

[0027] Referring to FIGS. 1 and 2, the heat sealable inner layer facilitates manufacture of the storage bag 100 by allowing first and second inner surfaces 108, 109 of the respective sidewalls 102, 104 to be joined together by the heat seals formed along the first and second side edges 110, 112 and the closed bottom edge 114. Additionally, the flexible characteristic of the heat sealable layer may enable the storage bag to maintain sufficient flexibility in freezer applications in comparison to the relatively tougher material of the air permeable, outwardly disposed layer. The relatively stronger, outwardly disposed, air permeable layer 142, though not as susceptible to forming heat seals, provides sufficient toughness and strength to the storage bag to resist destructive stretching and deformation during evacuation. Additionally, the tougher, higher strength, material can better endure the conditions

that may be encountered during freezing, storage, or transportation than the heat sealable layer alone.

[0028] In the embodiment illustrated in FIG. 2, the sidewalls 102, 104 are comprised of the heat sealable layer 140 and the outwardly disposed higher strength layer 142 in direct contact with each other. Hence, the heat sealable layer 140 provides the inner surface 108, 109 of the sidewalls 102, 104, and the outwardly disposed higher strength layer 142 provides the outer surfaces 144 of the sidewalls. To produce the multilayered sidewall material, the heat sealable layer and the higher strength layer can be co-extruded together. Furthermore, while in the illustrated embodiment the heat sealable layer and the higher strength layer are shown in direct contact, in other embodiments a third gas permeable layer can be disposed between the two for, as an example, facilitating attachment of the heat sealable layer and the higher strength layer together.

[0029] In various embodiments, each sidewall can have an overall thickness 146 between the inner and outer surfaces as shown in FIG. 2. The thickness of each sidewall can be about 2.5 mils (0.001 inches) (0.0254 mm) or greater. For example the thickness can range from about 2.5 mils (0.001 inches) (0.0254 mm) to about 3.5 mils (0.0035 inches) (0.089mm). The inner heat sealable layer can comprise between about 5% to about 50% of the total thickness of each sidewall and the outwardly disposed strengthening layer can comprise the remainder.

[0030] Referring to FIG. 3, in other embodiments, the first and second sidewalls 152, 154 of the storage bag 150 can be made from a multilayered sheet having three or more air permeable layers. For example, the sidewalls may include an inner layer 156, a middle layer 158 and an outer layer 160. The inner heat sealing layer 156 may be similar to the inner layer 140 noted herein. The outwardly disposed, high strength layer 158, may be similar to layer 142 noted herein. The outer layer 160 may be an air permeable, outer protective layer. The outer layer 160 can be comprised of low density polyethylene, linear low density polyethylene (LLDPE), or ultra low density polyethylene (ULDPE). These materials have sufficient flexibility, as compared to high density polyethylene, to contribute to the overall flexibility of the sidewall and to provide the outer surface of the sidewalls with scratch resistant characteristic. In the

embodiment illustrated in FIG. 3, the inner layer 156 and the outer layer 160 can each comprise about 25% of the overall thickness of the sidewall and the middle layer 158 can comprise the remaining 50%. In other embodiments, the inner layer 156 may be in the range of 5% to 40% of the overall thickness of the sidewall, the middle layer 158 may be in the range of 90% to 20% of the overall thickness of the sidewall and the outer layer 160 may be in the range of 5% to 40% of the overall thickness of the sidewall.

[0031] Also shown in FIG. 3 is another manner in which the closed bottom end 164 can be formed. Rather than heat sealing two separate sheets or webs of material together, the storage bag 150 can be formed by folding a single sheet in half to form the two opposing sidewalls 152, 154. Thus, the closed bottom end 156 is formed as a continuous fold and no heat sealing of the bottom end is required. [0032] Referring to FIG. 4, there is illustrated another embodiment of a storage bag 170 in which each sidewall 172, 174 is made from different sheets having a different number of layers. For example, the first sidewall 172 includes both a heat sealing layer 176 and a high strength layer 178. The second sidewall 174 likewise includes the heat sealing layer 176 and high strength layer 178 but also includes an outer protective layer 180. The inner layer 176 may be similar to the inner layer 140 noted herein. The layer 178 may be similar to layer 142 noted herein. The outer layer 180 may be similar to layer 160 noted herein.

[0033] The one-way valve element attached to the storage bag can be any suitable one-way valve element. For example, referring to FIGS. 5, 6, and 7, the one-way valve element 200 for use with a storage bag of any of the foregoing types can include a rigid valve body 210 that cooperates with a movable disk 212 to open and close the valve element. The valve body 210 includes a circular flange portion 214 extending between parallel first and second flange faces 220, 222. Concentric to the flange portion 214 and projecting from the second flange face 222 is a circular boss portion 218 which terminates in a planar boss face 224 that is parallel to the first and second flange faces. The circular boss portion 218 is smaller in diameter than the flange portion 214 so that the outermost annular rim of the second flange face 222 remains exposed. The valve body 210 can be made from any suitable material such as a

moldable thermoplastic material like nylon, HDPE, high impact polystyrene (HIPS), polycarbonates (PC), and the like.

[0034] Disposed concentrically into the valve body 210 is a counter-bore 228. The counter-bore 228 extends from the first flange face 220 part way towards the boss face 224. The counter-bore 228 defines a cylindrical bore wall 230. Because it extends only part way toward the boss face 224, the counter-bore 228 may form within the valve body 210 a planar valve seat 232. To establish fluid communication across the valve body 210, there is disposed through the valve seat 232 at least one aperture 234. In the illustrated embodiment, a plurality of apertures 234 are arranged concentrically and spaced inwardly from the cylindrical bore wall 230. [0035] To cooperatively accommodate the movable disk 212, the disk is inserted into the counter-bore 228. Accordingly, the disk 212 may be smaller in diameter than the counter-bore 228 and has a thickness as measured between a first disk face 240 and a second disk face 242 that is substantially less than the length of the counter-bore 228 between the first flange face 220 and the valve seat 232. To retain the disk 212 within the counter-bore 228, there is formed proximate to the first flange face 220 a plurality of radially inward extending fingers 244. The disk 212 can be made from any suitable material such as, for example, a resilient elastomer. [0036] Referring to FIG. 7, when the disk 212 within the counter-bore 228 is moved adjacent to the fingers 244, the valve element 200 is in its open configuration allowing air to communicate between the first flange face 220 and the boss face 224. However, when the disk 212 is adjacent the valve seat 232 thereby covering the apertures 234, the valve element 200 is in its closed configuration. To assist in sealing the disk 212 over the apertures 234, a sealing liquid can be applied to the valve seat 232. Furthermore, a foam or other resilient member may be placed in the counter-bore 228 to provide a tight fit of the disk 212 and the valve seat 232 in the closed position.

[0037] To attach the valve element 200 to the first sidewall, referring to FIG. 7, an adhesive can be applied to the exposed annular rim portion of the second flange face 222. The valve element 200 can then be placed adjacent the exterior surface of the first sidewall with the boss portion 218 being received through the hole disposed into

the sidewall and thereby pass into the interior volume. Of course, in other embodiments, adhesive can be placed on other portions of the valve element, such as the first flange face, prior to attachment to the sidewall.

[0038] In other embodiments, the one-way valve element can have a different construction. For example, the one-way valve element can be constructed from flexible film materials.

[0039] Referring to FIG. 8, a flexible one-way valve element 310 can include a flexible, circular base layer 312 that cooperates with a correspondingly circular shaped, resilient top layer 314 to open and close the valve element. The top and bottom layers can be made from any suitable material such as, for example, a flexible thermoplastic film. Disposed through the center of the base layer 312 is an aperture 316, thus providing the base layer with an annular shape. The top layer 314 is placed over and adhered to the base layer 312 by two parallel strips of adhesive 318 that extend along either side of the aperture 316, thereby covering the aperture with the top layer and forming a channel. The base layer 312 is then adhered by a ring of adhesive 320 to the flexible bag 300 so as to cover the hole 308 disposed through the first sidewall 302.

[0040] When a pressure differential is applied across the valve element by, for example, placing the nozzle of an evacuation device adjacent the first sidewall 302 about the valve element, the top layer 314 can be partially displaced from the base layer 312 thereby exposing the aperture 316. Air from the interior volume 306 can pass through the hole 308 and aperture 316 and along the channel formed between the adhesive strips 318 where the removed air enters the evacuation device. When the suction force generated by the evacuation device is removed, the resilient top layer 314 will return to its prior configuration covering and sealing the aperture 316. The valve element 310 may also contain a viscous material such as an oil, grease, or lubricant between the two layers in order to prevent air from reentering the bag. In another embodiment, the base layer 312 may also be a rigid sheet material. [0041] Illustrated in FIG. 9 is another embodiment of a valve element 410 that can be attached to the flexible plastic bag 400. The valve element 410 is a rectangular piece of flexible thermoplastic film that includes a first end 412 and a second end 414.

The valve element 410 is attached to the first sidewall 402 so as to cover and seal a hole 408 disposed through the first sidewall. The valve element 410 can be attached to the sidewall 402 by patches of adhesive 418 placed on either side of the hole 408 so as to correspond to the first and second ends 412, 414. When the nozzle attached to an evacuation device is placed adjacent the first sidewall 402 about the valve element 410 or the sidewalls are squeezed together, air from the interior volume 406 displaces the flexible valve element 410 so as to unseal the hole 408. After evacuation of air from the interior volume 406, the valve element 410 will again cover and seal the hole 408.

[0042] As mentioned above with reference to FIG. 1, to improve evacuation of air from the vacuum storage bag 100, at least one of the sidewalls 102, 104 may include a textured portion 500 on the inner surface 108, 109 thereof. Referring to FIG. 10, the textured portion 500 includes a plurality of alternating raised peaks 502 and recesses 504 that are formed into the inner surface. When the valve element 130 is engaged to the nozzle 506 of a vacuum source to evacuate the interior volume 106 such that the first and second sidewalls 102, 104 collapse adjacent to each other, the raised peaks 502 contact the valve element 130 thereby providing clearances that function as evacuation passages within the recesses 504. Accordingly, the recesses 504 allow air, indicated by arrow 508, from within the interior volume 106 to continually access the valve element 130 and thus the textured portion 500 prevents clogging of the valve element.

[0043] The textured portion can be produced by any suitable method including, for example, embossing or coining the air permeable sheet material used to produce the bag sidewalls. Because embossing the sheet material may reduce the thickness of the sheet material in certain areas, it may be necessary to start with a thicker sheet and then manufacture or process the sidewalls to the desired finished thickness. [0044] The vacuum source connected to the nozzle 506 in FIG. 10 can be any suitable vacuum source including, for example, hand-operated pumps, mechanical pumps, water aspirators, oral suction, and the like. Alternatively, the flexible bag can be evacuated by forcibly collapsing the flexible sidewalls together.

[0045] In the embodiment illustrated in FIG. 11, the peaks 502 can be formed along the crests of a first plurality of raised ridges 510 that extend along the inner surface. The first plurality of ridges 510 can be arranged parallel to and spaced-apart from each other. The recesses 512 are therefore defined within the clearances between the ridges 502. In the illustrated embodiment, a second plurality of parallel ridges 516 extends along the inner surface normal to and intersecting the first plurality of ridges 510 to form a grid-like pattern. In another embodiment, the recesses can be formed within a grid- like pattern of grooves disposed into the inner surface, thus forming the raised peaks as a series of protuberances separated by the grooves. For example, in the embodiment illustrated in FIG. 12, a first and a second plurality of grooves 522, 524 are disposed into the textured portion 500 and are arranged orthogonally to each other. The grooves 522, 524 define a plurality of raised portions 526 that are square in shape. Air can communicate along the grooves 522, 524 between the raised portions 526 even after the sidewalls have been collapsed together. In another embodiment illustrated in FIG. 13, the textured portion 500 can include protuberances 530 having smaller, circular shapes that are randomly dispersed along the inner surface 109 that are segregated from each other by arbitrarily-shaped recessed spaces 532 therebetween. Of course, the textured portion can have any other suitable shape, such as diamond-shaped ridges or grooves, horizontally arranged ridges or grooves, vertically arranged ridges or grooves, patterned or random curved- shaped ridges or grooves, etc.

[0046] Referring back to FIG. 1, the textured portion 500 can be provided over substantially the entire second inner surface 109 between the first and second side edges 110, 112 and between the closed bottom edge 114 and fastening strips 120, 122. Moreover, the first inner surface 108 of the first sidewall 102 can likewise be provided with a textured portion. A benefit of providing the textured portion throughout the bag is that the recesses extend over the inner surface and are interconnected with one another. Accordingly, air at any location within the interior volume 106 can access the valve element 130 along the interconnected recesses even as the opposing first and second sidewalls 102, 104 collapse together, thereby preventing air in the interior volume from becoming trapped.

[0047] Of course, in other embodiments, the textured portion need not be provided over substantially the entire inner surface. For example, in the embodiment illustrated in FIG. 14, the textured portion is provided as a relatively narrow, vertical strip 540 along the first edge 110 of the second sidewall 104 arranged to correspond to the location of the valve element 130. The remainder of the second inner surface is formed as a substantially smooth portion 542. An advantage of providing the textured portion as a narrow strip 540 adjacent the smooth portion 542 is that food items stored in the interior volume 106 are less likely to contact the textured portion, and are therefore less likely to retain unsightly impressions upon removal from the bag 100. In another embodiment illustrated in FIG. 15, the textured portion is provided as a T- shape 550 having a horizontal strip 552 and an intersecting vertical strip 554. The horizontal strip 552 extends between the first and second side edges 110, 112 while being spaced-apart from the bottom edge 114. The vertical strip 554 extends between the bottom edge 114 and the horizontal strip 552 while being spaced-apart from the first and second side edges 110, 112. Accordingly, the T-shape textured portion 500 can extend substantially throughout the interior volume 106 between the opposing side edges 110, 112 and the top and bottom edges 114, 116 while still providing substantially smooth portions 556, 558.

[0048] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0049] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were

individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0050] Preferred embodiments of this invention are described herein, including the best mode known to the inventor(s) for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor(s) expect skilled artisans to employ such variations as appropriate, and the inventor(s) intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.