CA1068238A - Container, vacuum package, and packaging process - Google Patents
Container, vacuum package, and packaging processInfo
- Publication number
- CA1068238A CA1068238A CA233,760A CA233760A CA1068238A CA 1068238 A CA1068238 A CA 1068238A CA 233760 A CA233760 A CA 233760A CA 1068238 A CA1068238 A CA 1068238A
- Authority
- CA
- Canada
- Prior art keywords
- container
- sealed
- wall
- path
- section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000012858 packaging process Methods 0.000 title abstract description 3
- 239000012530 fluid Substances 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 20
- 230000009975 flexible effect Effects 0.000 claims abstract description 16
- 238000009461 vacuum packaging Methods 0.000 claims abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 230000035699 permeability Effects 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 16
- 238000007789 sealing Methods 0.000 claims description 16
- 238000003466 welding Methods 0.000 claims description 14
- 229920001169 thermoplastic Polymers 0.000 claims description 5
- 239000004416 thermosoftening plastic Substances 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 3
- 230000006854 communication Effects 0.000 claims description 3
- 239000002654 heat shrinkable material Substances 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 8
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 8
- 235000013372 meat Nutrition 0.000 description 6
- 229920001577 copolymer Polymers 0.000 description 5
- 230000014759 maintenance of location Effects 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 4
- -1 cement Chemical class 0.000 description 4
- 238000010276 construction Methods 0.000 description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- 235000015278 beef Nutrition 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- 238000004806 packaging method and process Methods 0.000 description 3
- 235000020989 red meat Nutrition 0.000 description 3
- 230000001755 vocal effect Effects 0.000 description 3
- LGXVIGDEPROXKC-UHFFFAOYSA-N 1,1-dichloroethene Chemical compound ClC(Cl)=C LGXVIGDEPROXKC-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 2
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- YSGQGNQWBLYHPE-CFUSNLFHSA-N (7r,8r,9s,10r,13s,14s,17s)-17-hydroxy-7,13-dimethyl-2,6,7,8,9,10,11,12,14,15,16,17-dodecahydro-1h-cyclopenta[a]phenanthren-3-one Chemical compound C1C[C@]2(C)[C@@H](O)CC[C@H]2[C@@H]2[C@H](C)CC3=CC(=O)CC[C@@H]3[C@H]21 YSGQGNQWBLYHPE-CFUSNLFHSA-N 0.000 description 1
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 101100238304 Mus musculus Morc1 gene Proteins 0.000 description 1
- 241000282337 Nasua nasua Species 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 241000193803 Therea Species 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical group ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
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- 229920001038 ethylene copolymer Polymers 0.000 description 1
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- 229920000578 graft copolymer Polymers 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
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- 229920001155 polypropylene Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 239000012858 resilient material Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
Landscapes
- Packages (AREA)
Abstract
CONTAINER, VACUUM PACKAGE, AND PACKAGING PROCESS
Abstract of the Disclosure The invention disclosed is directed to an improved sealable container which comprises a wall including a wall region having opposed first and second flexible wall portions, a check valve integral with the wall and including an openable port disposed in the wall region, and at least one elongate section of sealed engagement of the first wall portion with the second wall portion. The port and spaced sealed section define a fluid flow path extending from the container exterior adjacent the port to an interior zone of the container, the path being substantially sealable against fluid flow, and the wall being characterized with low permeability respecting water vapor, air, and air components. The con-tainer is highly suitable for maintaining subatmospheric pressure within packages, also disclosed, which may be formed of the container with a product therein. A process for vacuum packaging is further disclosed.
Abstract of the Disclosure The invention disclosed is directed to an improved sealable container which comprises a wall including a wall region having opposed first and second flexible wall portions, a check valve integral with the wall and including an openable port disposed in the wall region, and at least one elongate section of sealed engagement of the first wall portion with the second wall portion. The port and spaced sealed section define a fluid flow path extending from the container exterior adjacent the port to an interior zone of the container, the path being substantially sealable against fluid flow, and the wall being characterized with low permeability respecting water vapor, air, and air components. The con-tainer is highly suitable for maintaining subatmospheric pressure within packages, also disclosed, which may be formed of the container with a product therein. A process for vacuum packaging is further disclosed.
Description
-^ - 1068238 This in~ention relates to a Yacu~m package including a container haYing a sealed flo~ path;to the` containe~! and to a yacuum packaging process.
Nu~erous selecti~el`y ~ented containers are aYailable in the pXior art. See, fox example~ ~etzgex~ U. S. Patent 2,821,338, ~or a description of a container equippe~ with a check val~e closure which is descrihed as aaapted to assume an open position for egress o~ air from the container ~oay to a Yac~um chamber and a closed position for sealing an opening in the body and maintaining a vacuum therein. Metzger disclo~es a7r7~t~ons of his Yalve-equipped container in U. S. Paten and U. S. Patent 2,946,502. The various Metzger Yalves are formed separateIy of the container bodies.
~l U. S. Patent 3,133,691 to Corbett discloses a laybrinth i! lS vent for a thermoplastic bag. In essence, it is said, the labyrinth pro~ides an exhausting passage of considerable length in a relatively small area. The contents, disclosed to be sand-~ like hygroscopic compounds, such as cement, are described as j filling the labyrinth to some extent. After filling the bag and venting air therefrom, external water vapor enters the labyrinth and cures the hygroscopic material therein to thereby `~; seal the labyrinth.
, Yates, U. S. Patent 2,361,344, discloses a package includin~
-: :~
a gas liberating material contained under pressure in a bag of resilient material having a heat-sealed seam provided with a Dormally closed vent which is defined by an elongated unsealed seam portion. The gas pressure within the bag is continuously maintained at least slightly above the external pressure with the opposed walls o~ the Yent normally contacting one another and bein~ held in such contact by the inherent xesiliency of the ba~ material. The Yent hag disclosed b~ ~ates is inherentl~
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of substantially limited utility in ~he vacuum packaging art for reasons including the inherent closing of the vent when the interior bag pressure exceeds the exterior bag pressure, thereby precluding effecti~e vacuumizing through the vent.
However, the prior art has failed to recognize that articles can be simply and efficiently vacuum packaged within a container provided with a check val~e formed integrally with the container, as herein taught.
According to the present invention there is provided a sealable container which comprises: (a) a wall including a wall region having opposed first and second flexible wall portions; (b) a check valve integral :~ with the wall and including an openable port disposed in said wall region;
and (c) an elongate section of sealed engagement of the first wall portion with the second wall portion; said first and second wall portions having ; opposed interior faces that are self-welding such that when the container is subjected to heat, the opposed faces bond to one another to close off the check valve and render the section of sealed engagement indistinguishable from the surrounding walls, said port and sealed section defining a fluid ` flow path extending from the container exterior adjacent the port to an interior zone of the container, said path being substantially sealable against fluid flow, said wall being characterized with low permeability respecting water vapor, air, and air components.
Preferably, there are at least two elongate spaced apart adjacent sections of sealed engagement of the first wall portion with the second wall portion.
, In a preferred embodiment the wall region terminates to an end edge of the wall and the openable port is an unsealed portion of the end edge.
, ~ Generally improved packages may be prepared from :!
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embodiments of the container wherein first transverse ends of two or more adjacent sections of sealed engagement are coterm-; inous with interior surface portions of the container, thereby providing corners or extremities of the container interior, each one of at least two of the sections extending from its first end generally toward the opposite corner. In such ; embodiments, first and second adjacent sealed sections; which may be slightly arcuate or otherwise generally straight, are preferably generally parallel each to the other, each section terminating to a second end disposed preferably diagonally ofthe first end of the other section, the longitudinal extents of the sections being preferably sufficient in length to provide a first elongate portion of the flow path, said path portion extending transversely throughout the path portion from a longitudinal edge of the first sealed section to an opposite longitudinal edge of the second sealed section. These containers preferably include a third elongate section of sealed engage-~, ment of the first wall portion with the second wall portion, the third sealed section being preferably generally parallel to the first and second sealed sections, the third sealed sectionhaving a first end preferably coterminous with a third interior surface portion of the container, the first and third sealed sections being spaced in opposite directions from the second sealed section and providing a generally U-shaped turn portion of the flo~ pat~ about the second end of the second section.
The longitudinal extent of said third sealed section is prefer-ably sufficlent in length to provide a second elongate portion o the flow path extending transversely throughout from a longitudlnal edge of the third sealed section to an opposite 3a longitudinal edge of the second sealed section~
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Desirably, the wall is of thermoplastic composition, at least in the flexible wall portions thereof.
In another preferred embodiment, the container wall has a second wall region adjacent the included wall region set forth above, the second wall region defining the interior zone of the container and being (a) openable for receiving a product into the zone and (b) sealable for retaining the received product and for substantially preventing fluid flow communica-tion of the container interior with the container exterior through the second wall region.
In a highly preferred embodiment, the container wall is an open end bag formed of collapsible tubular sheet material.
Thus the wall may be a generally flat tube of flexible sheet material wherein the tube has first and second opposite ~ -longitudinal folds, a first one of the elongate sections of - sealed engagement extends from the first longitudinal fold toward the second fold and terminates to an opposite end of the first section spaced from the second fold, and a second one of the elongate sections of sealed engagement extends from the second lateral fold toward the first fold and terminates to an ,~; opposite end of the second section spaced from the first fold.
:~
The present container is highly suitable for forming sealed vacuum packages having good vacuum retention properites, without requiring presence of packaged product within the flow path nor dissipation of the product to seal the package.
Thus, the invention also provides a package including a container of the above described type, a product within the container, and gaseous composition at subatmospheric pressure within the container, said path being substantially sealed 3Q against fluid flow and including opposed wall portions in self-:
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) ~,~. -5-; ~, , . ,- . - . .. ,, . . .. . . .. . . . .: . , 1068~38 welding interengagement.
The path may be substantially free of product and pressure sealed, as desired. -In a preferred embodiment of the package, the container includes a sealed second wall region closely ad]acent a substantial portion of the product or article. In this embodiment the wall forms a skin about the product, thereby . . .
forming a vacuum skin package.
; The present invention also provides a process for vacuum packaging, which comprises:
(al receiving a product into the interior zone of a container of the above described type;
, (b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through the port to reduce -the gaseous pressure to subatmospheric pressure substantially *, throughout the container; and 1 (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure ~ithin the container.
As used herein "low permeability respecting water vapor, air and air components" means that the material or member thus characterized is sufficiently resistant to permeation such that subatmospheric pressure within ~ackages including a sheet or film of the material as an enclosing member is sub-stantially maintained for extended periods in gaseous environ-,y C~ ~ -6-.
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.
ments normally encountered in storing and handling the packages. Typically, the gaseous environment is air at a pressure from about 740 to 780 mm. Hg absolute and at a temper-ature from about 0F. to about 120F. -,,1 .. :
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~068238 The present invention will become more appar~nt frQm the followin~ ~etailed d~scription ta~en with the accompanying drawing whereill similar elements al-e identified ~ like numera]s thxoughout. .~ `
In the ~rawing:
FIG. 1 is a plan yie~ illus.trating a container having a check valve formed inte~rally with a wall the~eof and embodyin~ .
the present invention; ~ .
FIG. 2 is a partial perspectiYe Yiew illustrating corners 10 of a container interior wherein each. of.two secti~ns of sealed ; engagement of opposea container wall portions is coterminous with an interior corner and extends toward a generally opposite ~ -,,, ^ interior corner;
FIG. 3 is a plan view of an embodiment container ha~ing ~ 15 three generally parallel heat sealed sections;
.~ FIG. 4 is a plan view of a~-~ther embodiment container having slightly arcuate heat sealed sections wi~h a port dis-posed therebetween, . FIGS. 5-7 are plan views illustrating other containers . 20 embodying this invention;
, FIG. 8 is a perspective view generally illustrating a i package including the container of FIG. 3 and embodying the ~ package of the present invention in an aspect thereof;
'1 ` ~ `~ ' ; FIG. 9 is a plan view of the package;
FIG. lO is a sectional view taken along the line lO-lO
,.~g~
in FIG. 9, illustrating a ~tep in the preparation of the package with the check valve in open position for exhausting air; and }~ FIG. 11 is a sectional view similar to FIG. lO, showin~
30 the check valve in closed position.
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~ 7-: ` . . : .. . ', ~ . ' .
1(~682313 Referrin~ now to the drawing,especially FIG. 1 and ~I~. 2, illustxated therein ~s sealable con~ainer 10 for~ed by wall 12 which desirably is characterized ~ith low permea~ility respecting watex Yapor, aix and air components. The ~all includes wall 5 region 14 ha~in~ opposed fixst and second fle~i~le ~7all portions 16 and 18 proYided with elongate space~ apart aajacent sections 24 and 26 of sealed interengagement. Con~eniently, the wall ~ay be of heat seala~le material Wit~l the seals 24 and 26 pro-ided therein by any suita~le heat sealin~ means.
The container includes a check valYe 20 inte~ral with the wall and including openable port 22 disposed in wall region 14.
The port preferably is pro~ided by separate or separable unsealed portions of en~ edge 32 to which the wall region terminates.
The port and spaced sealed sections define a fluid flow path 15 schematically shown by arrows 28 which illustrate flow of fluid, typica~ly gaseous c~mposition, e.g., air, from interior -zone 30 of the container to the container exterior. The path or passage ~ extends from the container exterior adjacent the port to the i interior zone. The path is sealable against fluid flow by any 2a suitable means, e.g., pressureO It is found that the path is sufficiently pressure sealable that upon applicàtion of differ- -ential pressure effected by reducing gaseous pressure within the container to su~atmospheric pressure and e~posing the con-tainer exterior to atmospheric pressure, not only do opposed 25 flexibIe wall portions collapse into interengagement transversely 'i:
of the path, but also the path is thereby sufficiently sealed to maintain the subatmospheric pressure for extended periods.
Generally impro~ed Yacu~m packages may be prepared wherein ~i~ first transYerseend 34 of sealed section 24 is coterminous with i ~ 30 a first intexior surface portion of the container, thereby pro~
-~ ~idin~ corner 36 of the container intexior, and first transvers~
end 38 of sealed section 26 is coterminous with a second interior ~ ~ .
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surface portion of th~ container, thereby proYiding corners 40 and 41 of the`con~àinex interior: Sealed ~ection 24 preferably e~tends fronl its *irst end generall~ toward corner 41 and sealed ~ection 26 pxeferabl~ extends frQm its first end generally toward corner 36. The sealea sections, which ~ay be'slightly arcuate or otherwise'generally strai~
are preferably genexally parallel each to the other r each section terminating to a second transvexse ena disposed pre-ferably diagonally from the first end of thè`other section, the longitudinal extents of the sections being preferably sufficient in length to provide a first elongate portion of '~he flow path, the path portion extending trans~ersely throughout from longitudinal edge 42 of sealed section 24 to opposite longitudinal edge 44 of sealed section 26.
As illustrated in FIG. 3, the container préferably includes third eilongate section 27 of sealed engagement of the wa~l portions 16 and 18t the third sealed section be~ng preferably generally parallel to sealed sections 24 and 26 ana having a first end preferably coterminous with a third interior surface portion of the container at corner 46, sealed sections 24 and 27 being spaced in opposite directions from sealed section 26 and providing a generally U-shaped turn portion of tha flow path about the second end thereof, as schematically illustrated by arrow 29. The longitudinal extent of sealed section 27 is ;2:5:~ pre~ferably sufficient in length to provide a second elongate portion of the flow path extending trans~ersely throughout from a longitudinal edge of the sealed section 27 to an opposite longitudlnal edge of sealed section 26.
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The containers illustrated in FI~. l and ~IG. 3 axe , generally found to be c~aracterized with an e~cellent balance of ease of Yacuumization and sealahility of the check ~alYe.
Two ox moxe of these containers ~ay be effectiYel~ fo~med into S Yacuum packages using simultaneous Yacuumizin~ thereof in the same chamber with ImproYements in eff~sienc~ relati~e to many heretofore known packaging techniques.
It is found that containers substantially identical to the container illustrated in FIG. l except not including at least two sp(aced apart adjacent sections of sealed engagement bordering transversely opposite sides of the flow path are not sufficiently sealable by differential pressure to suitably maintain a vacuum therein without employment of other means for sealing the flow path. Containers illustrated by FIG. 3 and having three or more seals disposed therein for providing a generally U-shaped turn portion ~f the flow path are gen~rally found to be even more effectively sealable trans~ersely of the flow path, as under a pressure differential resulting from vacuumizing and thereafter exposing the vacuumized container to air at atmospheric pressure.
Container lO may be of flattened tubular sheet material wherein opposed wall portions 16 and 18 are closely adjacent ~ one to the other. In general, for commercially acceptable ;~ vacuum packaging speeds using this construction it is critical 25 ~that the minimum distance transversely of the flow path be at least 3/4 inch and preferably at least l inch. For Yacuumizing at higher speed or obtaining higher package Yacuum using any -gi~en evacuation rate, the minimum distance trans~ersely of the flow path is at least l l/4 inches and preferably at least l 3/4 inches.
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In e~bodiment cons~uct;~ns of the present container , . .
, . . ~ , ,~
1~)68Z38 wherein the ~all is of flattened tubular film ox sheet material with one ox morc lat~ral folds, at ieast one of the flo~ ~ath bordering seals prefera~ly extends from a fold, therehy improying sealability of the flow path.
S The present container ~a~ include one ox more arcuate sections of sealed interengagement as illustrated by slightly arcuate heat seals 48 and 5~ formed in generally parallel manner one to the other, thereby sealingly engaging opposed flexible wall portions 54 and 52 of bag 110 tFIG~ 4). The 10 exhaust port may be provided by forming the bag with separated or separable unsealed portions of end edge 56, which may be arcuate as shown and to which the wall region containing .
the arcuate seals terminates, or by pro~iding one or more slits through the bag wall as illustrated, for example, ~y :
15 slit 5g disposed intermediate the seals through flexible wall portion~54. In containers where-in a slit port is provid~d, end 56 may be sealed or open as desired.
Other containers embodying the present inYention are . illustrated by containers 210, 310, and 410 of FIG. 5, FIG. 6 20 and FIG. 7, respectively. These containers may be of the : construction set forth above with reference to the.containers of FIG. 1, FIG. 3 or FIG. 4, except as follows. Container 210 includes two elongate spaced apart adjacent sections 60 and 62, each being of sealed interengagement of opposed flexible wall 25 portions 64 and 66 which may be of one piece flattened tubular 1~ :
construction having lateral edge folds 68 and 70. The container preferably further includes generally L-shaped section 72 of sealed interengagement of the wall portions. The arm of the :~ L disposed transYersely of the container may be generally parallel ` 30 to seals 60 and 62, as sho~n, while the arm of the L disposed longitudinally of the hag is preferably spaced from lateral I, --1 1--- .
~, . ! . ' " ,, -- 106823~3 fold 68 a suitable distance,' e.g. aho~t 1 inch or more to pxoyide a defined flo~ path portion extending su~stantially to the'opposite end of the ~all. Bags thus formed;ma~ be found - ' to aid in substantially preYentin~ residual air pockets in S ,vacuum packages formed thexeof ~ith the ~all closely ab~ut packaged fresh red meat or other pro~ucts.
Container 410 is a vaxiation of container 10, shown in FIG. 1, wherein there is further pro~ided interrupted section 74 - - ' of sealed interengagement of flexible wall portions 16 and 18. `' Seal 74 extending longitudinally of the container or bag from genexally near an end of seal 26 to near opposite openable end 23 provides additional plural definitive flow path portions for aid , -' in evacuating gaseous composition from the container interior during Yacuumizing.
Container 310 (FIG. 6) illustrates an embodiment of the !~' invention wherein the container,,which may be a bag having , l .
openings at opposite ends 80 and 82, is provided with a ' , plurality of longitudinal seals 76 interengaging opposite flex- -ible wall portions 84 and 86. The seals extend from end edge , ~ 2~ 80 having a plurality of ports 88 to which plural flow paths ,' schematically indicated by arrows 90 terminate. Opposite laterally disposed seals 78 terminating to lateral folds of the ' ~ ' ~- container wall may be included ~or further aid in remo~ing air ',or other gaseous composition from the container interior.-- ' 5~ FIG. 8 illustrates package 92 including flexible container 10 '' (FIG.~3) which may~be o~ flexible thermoplastic film and bulky `a~rticle~94 within the container. Substantial portions of the ' -~' article may be closely adjacent portions of the container which -may~be~trAnsparent~as shown for xeady ~isibility of the article.
30~ The~pxessure;of ~le gaseous atmosphere within the container ~ '' is~belo~ the pres'sure on the container exterior, which may be ,~
. . , 106823~
normal atmospheric pres`sure,` and substantially below 760 mm. H~
absolute, if de ired' Th~ container interior may be at any suitable Yacuum leYel. In high ~acuum packa~ing application~
the pxessure ~ay be suhstantiall~ lo~, e.g. less than ~QQ mm. Hg S absolute, ~hile in lo~ Yacu~m applications the interior pressul-e may be, for example, about 720 to about 750 ~m. Hg. absolute.
The container,which may be of generally tubular construction sealed at one end, as for example by clip 96, includes wall portion 16 and oppositely adjacent wall portion 18. The opposed 10 wall portions adjoin one another at opposite edge folds which ;
may be provided by flattening the tubular wall in preparing the container.
The port and the spaced apart heat sealed sections define a fluid flow path extending from an interior zone of the container to the container exterior adjacent the port. The path i~Jdiagrammatically illustrated by the arrows in FIG. 9.
When the container is formed into a package as illustrated in FIG. 8, the path is substantially sealed against fluid flow by collapsed engagement of path-bordering portions of the 20 opposed flexible wall portions. As will become more apparent fxom the description below, the collapsed engagement is effected by applying relatively high pressure to the exterior of the ;~ package, the relative.-y high pressure being greater than the gaseous pressure within the container.
The package 92 may conveniently be formed using a tubular ~ film~container of generally rectangular shape when flattened, c~ and, after 1attening, proYiding heat sealed sections therein as~descrlbed~aboYe. An article to be packaged is inserted within an opened end of the container, which end is thereafter 30 sealed~as by clip 96 or other suitable means such as heat sealin~
or the like, the package 92 which is being formed now appearing as ~illustrated by FIG. 8 and FIG. 9.
-12n-The package heing formed is thereafter inserted into a Yacuum chambex or otKer suitable`zone which ma~ ~e`~aintained at a subatmospheric pressure of, fox example~ frQm a~out lO
to about l~0 ~m. H~ ahsolute`or more, there~ effecting S withdxawal of at least a poxtion of the air or ot~er gaseous environment fxom within the`container through t~e check valYe.
During va~uumi~ation and aix e~haustion or escape the check valve is opened by the greater gaseous pressure within the `"
CQntainer as shown in FIG. lO.
After the internal container pressure is reduced to a suitable value, e.g., from about 10 to about 100 mm. Hg., vacuumization is discontinued as, where a Yacuum chamber is used, by increasing the chamber pressure or removal of the package being formed from the chamber to a zone of higher ~-15 pressure which conveniently may be an environmént of air at standar~ or higher atmospheric pressure. The pressure d~ffer-I ential from without to within the container collapses the ¦ opposing wall portions 16 and 18 into substantially uniform ¦~ engagement resulting in seal-providing engagement of path-20 bordering portions of the opposed wall portions 16 and 18, as shown in`FIG. 11. The resulting package effective]y seals the contained article from air and other gaseous environments .~ ~
j ~ normally encountered in storing, distributing and di~splaying a vaxiety of articles, including b~t not limited to comestibles 2S and durable goods.
In an embodiment wherein the container is of heat-shrinkable sheet material, as may be desired, the package may next be heated to proYide a heat shrunk package. Heat shrinking is a suitable means for aiding in retention of the p~th seal which 3a is effec~ed-by the higher exterior pressure, as may be desired in rough handling applications.
., .~: ~ , ~ . , ` .
,, :
1068Z3~3 The sheet material o~ the container ~ay be o any suitable composition, including paper, metal (e~`g. aluminu~ ~oil~ xesins - ~e~g~ thex~opla~tics) and the like. ~uitahle`the~mo~lastic compositions incl~de for example, poly~ers of ethylene, propylene, - 5 yiny-lidene chloride, ~inyl chIoride, interpolymer~ thereof with other po]ymerizable ~onomers, block pol~mers thereof, graft polymers thereof, ethylene Yinyl alcohol copolymers, and the like. Laminates of two or,more plies are also suitable sheets from which the container and package may be prepared. Suitable laminates include, for example, laminated films or sheets including a polyethylene or polypropylene ply with an adjacent saran ply. A preferred laminate includes two plies of poly-ethylene or an ethylene copolymer (e.g. ethylene ~inyl acetate copolymer) with a saran ply therebetween.
The term saran is applied to a family of thermoplastic resinsj~viz, vinylidene chloride-~polymers, and copolymer~ of vinylidene chloride with other monomers such as -Yinyl chloride, acrylonitrile, methyl methacrylate, acrylates, acrylate esters, vinyl acetate, and the like. Copolymars of Yinylidene chloride 20 with other monomers are generally described in terms of the weight ratio of the monomer units in the ~copolymer Saran, by ` definition, has at least 50 percent Yinylidene chloride.
The inner surfaces of the container wall may be adapted for bonding one to another as by forming the wall of adhesive 25 ~material such as adhesive ethylene vinyl acetate copolymer (EYA) or ; providing a coati~g there~f on a substrate of other packaging material. EYA and other self-welding wall materials are eminently suitable.
The container component of the present package ~ay have an~ suitable wall ~ickness. Films ha~in~ thicknesses of from a~out 0-.5 t-o about 10 mils axe hi~hl~ suita~le.
Although the above description of the container has been , :: ~
~ -14-given principally with reference to a bag foxmed o~ ~lattened tubular sheet materic~l, pouches and other container f~ms are also within the scope o~ the present inyention. It is ~nder-stood that the opposed flexible wall portions of the present container-~ay ~e foxmed of any suitable constr~ction, including a single sheet or fil~ folded on itself ana pro~ided ~ith any suitable seal, e~g. a heat seal, along an end opposite the fold, two superimposed sheets or films heat or otherwise sealed at opposite ends thereof, and the like.
lOPxactice of the present inYention is further illustrated by the following non-limiting examples. The bags used in the `
exa~ples were prepared substantially as next set forth.
A tubular composite laminate ha~ing a transparent flexible wall was prepared by co-extruding through appropriate annular -die lands an inner layer of ethylene Yinyl acetate copolymer (EVA), an intermediate layer of a saran copolymer formed Df about 85 percent by weight of vinylidene chloride units and about 15 percent by weight of vinyl chloride units, and an outer layer of ethylene vinyl acetate copoly~er (EYA~. The co-extru~ion was effected using well known blow extrusion procedures therefor. ~he laminate wall was about two and one half mils in thicknes9 with the various layers having the following approximate thicknesses: the inner EVA layer, one half mil; the intermediate saran layer, one and one half mils;
25~ and the outer EVA layer, one half mil. The inside diameter of the tube was a~out 9 inches. The tubular laminate was passed through the nip of a pair of cooling rolls thereby proYiding a flattened tube about 14 inches in width haYing transYersely opposite~ lateral folds disposed longitudinally of the tube.
30~ - A plurality o~ gene~ally rectangular bags substantially ~ -as illustrated in FIG. 3 wexe proYided by transvexsely s~ering :: :
~ ~ .
~, ~; -15-~ ~ .
the tube alon~ widths thereof spaced about 3Q inches apart . lon~itudinally of the~`tu~e,:~ollo~ed~ ~y proYidin~ eàch seyered :: tube'seg~ent with a set of three elon~ate'transYerse'~enerally strai.ght heat seals a~out 1/16 inch in ~idth'adjacent an open end thexeof using well known heat sealing pxocedures.
EX~mple 1 Referring to FIG. 3, the distance longitudinally of one of the bags from the intermediately disposed heat seal 26 to ~ each of adjacent heat seals 24 and 27 was about 1 inch. The 10 distance i.s referred to hereinafter as X. This bag is referred to hereinafter as Bag A. Each of these seals was about 13 1/4 inches in length, extending from a side fold of the bag and ::
termina'ting to an end disposed at a distance Y of a~out 3/4 ineh from an opposite side fold, as measured generally parallel 15 to the other heat seals. The seal disposed closest to the ' .
nearest~end of the bag was space'd therefrom at a distanc~ of not more than about one inch.
The loading end of the bag, i.e. the end disposed further ~`: from the heat seals, was opened and a top butt beef portion ~ 20 having a m~nimum diameter of approximately 4 inches was inserted therethrough and received into the bag interior zone extending generally from near the loading end to near the opposite ed~e of heat seal 27 (FIG. 3). Thereafter, a region o~ the bag adja~cent;the loading end was provided with a substantially air-tight:seal using a~bag gathering and clip crimping method substantially as~disclosed in U. S. Pat. No. 3,11i,794 to Spolino.
:The~bag~now~having: one unsealed end and the beef portion therein was placed:~in a vacuumizing chamber e~uipped with a si~ht glass, after~which. air was remoYed from the chamber interior in 3~ su icient amount l-sing a Yacuum pump to decrease thè internal chamber:pressure to about 27 inche5 Hg vacuum wi~lin about ,~, . . . ..... .. ....
30 seconds, the chamber pressure quickly decreasin~ to about 21 inches ~Ig yacuum ~nd moxe sl~wly therea~t~x. The Yacuumizing included ~aintainin~ the appxoximate 27 inch Hg yac~ for about 10 seconds. Obser~ation~ made durin~ the ~acuumizing period showed that the interior and flo~ path zones o~ the ha~
initially expanded as the cha~er pressure decreased and thereafter contracted, shbwin~ that air was remo~ed from the bag interior through the port proYided by the openable ~ag end opposite the clipped end of the bag. After the vacuu~izing period, the chamber was opened, exposing the loaded ba~ to room air at approximately 30 inches Hg absolute pressure and resulting in portions of the bag wall collapsing into contact with the top butt and portions of the wall intermediate the flow path defining heat seals collapsing into sealing wall-to-wall in~rengagement-Within a brief period thereafter, the resulting seaLedvacuum package was placed in a bell jar, which thereafter was slowly evacuated until the bag interior expanded to an extent such that substantial portions of the bag wall were released 20 fromPcontact with the top butt. Obseryation of a vacuum guage provided on the bell jar showed that the ohser~ed extent of bag wall release occurred at a bell jar Yacuum o~ about 1 in. Hg.
For measurement purposes the vacuum achieYed in the package of thi-s example was taken as 1 in. Hg., i.e. the bell jar end 25 point vacuum.
The vacuum package made using Bag A is of good Yacuum retention in applications where rough handling is aYoided.
For rough handling, better Yacuum retention results hy pro-viding a further séal, for exa~ple, a high stren~th heat seal, 30~transver~ely of the ~low path after Yacuumization. The vacuumized bag may be exposed to at~ospheric pressure with :
good vacuum rete~ition for relativelv lon~ periods prior to fur~her sealing for rough handling applications.
~, `` 1068Z38 Ex`amples 2 and 3 Th.e`p~ocedure `o~ Example 1 was~repeated using t~o ~ags referred to hereinafter as Bag ~ and Bag C. These bags ~ere substantially the same :as Bag A except that at.least one of ~.
the length. and s.pacing of the heat ~eals 24, 26, and 27 (FIG. 3 were Yari.ed such that the~seal~to-seal distances X and the seal-to-fold distances Y were appxoximately as shown ~elow: ..
BAG X (inch~s? - Y tinches) Bag B l 7/8 ..
Bag C l l/8 l l/4 The results were substan~ially the same, Bags B and C
resulting in packages with approximately l inch Hg Yacuum as . measured using the belljar technique set forth in EXample l.
. ` Examples 4 and 5 j 15 The procedure of Example l was again repeated using two bags r~erred to hereinafter as(:Bag D and Bag E. These hags were substantially the same as Bag A except that the length and spacing of the heat seals 24, 26 and 27 (FIG. 3) were varied such that the seal-to-seal distances X and the seal-to-~`
fold distances Y were approximately as shown below:
BAG X (inches) Y (inches) Bag D l l/4 2 l/4 . , ~ . .
Bag E l l/4 2 l/4 The results:were even:better, Bag D resulting in a 5:~pac~age w1th about 2 inches Hg Yacuum and Bag E resulting in a package~:with between l and 2 inches Hg Yacuum, as determined `.
by~the~bell jar technique set forth in Example l.
30 ~
; -18-.
~x~n~les_ 6 and 7 The procedure of Example l was again repeated using two bags referxed to hereinaftex as Bag F and ~a~ ~. These ba~s were substantially the same as Bag ~ except that the length and spacin~ of the heat seals 24, 26 and 27 ~IG. 3~ were varied such that the seal~to-seal distances X and the seal-to-fold distances Y were approximately a~ shown below:
BAG X (inches) Y (ihches) .
Bag F 2 l/8 l l/2 Bag G 2 l/4 2 3/8 The results were even better than the results o~tained for Bag D, Bag F resulting in a vacuum package with about 4 inches Hg vacuum and Bag G resulting in a ~acuum package with about 7 inches Hg vacuum, as determined by the bell jar technique of Example l.
~ Examples 8 through 10 The procedure of Example l was again repeated using three bags referred to hereinafter as Bag H, Bag I, and Bag J. These bags were generally the same as Bag A except that the heat seals 24, 26, and 27 (FIG. 3) were varied such that the distances Xl ~: and X2 f~om the intermediately disposed heat seal 26 to one of the two adjacent heat seals 24 and 27 and to the other one of ~: the heat seals 24 and 27, respectively, and the distance Y were -:
approximately as follows:
B~ X1 (inches) ~ (inches) - Y (inches) Bag H 2 l/4 l 3/4 l l/2 .. -.
Bag I 2 l/4 l 3/4 3 Bag J 2 l/4 l 7/8 3 These bags were found eminentl~ suitable for vacuum ::: :
packa~ing, Bag H resulting in a good ~acuum package wi.th about
Nu~erous selecti~el`y ~ented containers are aYailable in the pXior art. See, fox example~ ~etzgex~ U. S. Patent 2,821,338, ~or a description of a container equippe~ with a check val~e closure which is descrihed as aaapted to assume an open position for egress o~ air from the container ~oay to a Yac~um chamber and a closed position for sealing an opening in the body and maintaining a vacuum therein. Metzger disclo~es a7r7~t~ons of his Yalve-equipped container in U. S. Paten and U. S. Patent 2,946,502. The various Metzger Yalves are formed separateIy of the container bodies.
~l U. S. Patent 3,133,691 to Corbett discloses a laybrinth i! lS vent for a thermoplastic bag. In essence, it is said, the labyrinth pro~ides an exhausting passage of considerable length in a relatively small area. The contents, disclosed to be sand-~ like hygroscopic compounds, such as cement, are described as j filling the labyrinth to some extent. After filling the bag and venting air therefrom, external water vapor enters the labyrinth and cures the hygroscopic material therein to thereby `~; seal the labyrinth.
, Yates, U. S. Patent 2,361,344, discloses a package includin~
-: :~
a gas liberating material contained under pressure in a bag of resilient material having a heat-sealed seam provided with a Dormally closed vent which is defined by an elongated unsealed seam portion. The gas pressure within the bag is continuously maintained at least slightly above the external pressure with the opposed walls o~ the Yent normally contacting one another and bein~ held in such contact by the inherent xesiliency of the ba~ material. The Yent hag disclosed b~ ~ates is inherentl~
.3.:
~ --2--:`f- :
,, -106823~
of substantially limited utility in ~he vacuum packaging art for reasons including the inherent closing of the vent when the interior bag pressure exceeds the exterior bag pressure, thereby precluding effecti~e vacuumizing through the vent.
However, the prior art has failed to recognize that articles can be simply and efficiently vacuum packaged within a container provided with a check val~e formed integrally with the container, as herein taught.
According to the present invention there is provided a sealable container which comprises: (a) a wall including a wall region having opposed first and second flexible wall portions; (b) a check valve integral :~ with the wall and including an openable port disposed in said wall region;
and (c) an elongate section of sealed engagement of the first wall portion with the second wall portion; said first and second wall portions having ; opposed interior faces that are self-welding such that when the container is subjected to heat, the opposed faces bond to one another to close off the check valve and render the section of sealed engagement indistinguishable from the surrounding walls, said port and sealed section defining a fluid ` flow path extending from the container exterior adjacent the port to an interior zone of the container, said path being substantially sealable against fluid flow, said wall being characterized with low permeability respecting water vapor, air, and air components.
Preferably, there are at least two elongate spaced apart adjacent sections of sealed engagement of the first wall portion with the second wall portion.
, In a preferred embodiment the wall region terminates to an end edge of the wall and the openable port is an unsealed portion of the end edge.
, ~ Generally improved packages may be prepared from :!
;.i D
embodiments of the container wherein first transverse ends of two or more adjacent sections of sealed engagement are coterm-; inous with interior surface portions of the container, thereby providing corners or extremities of the container interior, each one of at least two of the sections extending from its first end generally toward the opposite corner. In such ; embodiments, first and second adjacent sealed sections; which may be slightly arcuate or otherwise generally straight, are preferably generally parallel each to the other, each section terminating to a second end disposed preferably diagonally ofthe first end of the other section, the longitudinal extents of the sections being preferably sufficient in length to provide a first elongate portion of the flow path, said path portion extending transversely throughout the path portion from a longitudinal edge of the first sealed section to an opposite longitudinal edge of the second sealed section. These containers preferably include a third elongate section of sealed engage-~, ment of the first wall portion with the second wall portion, the third sealed section being preferably generally parallel to the first and second sealed sections, the third sealed sectionhaving a first end preferably coterminous with a third interior surface portion of the container, the first and third sealed sections being spaced in opposite directions from the second sealed section and providing a generally U-shaped turn portion of the flo~ pat~ about the second end of the second section.
The longitudinal extent of said third sealed section is prefer-ably sufficlent in length to provide a second elongate portion o the flow path extending transversely throughout from a longitudlnal edge of the third sealed section to an opposite 3a longitudinal edge of the second sealed section~
.~
. ,1 .
r~
~; ~. ~4~
Desirably, the wall is of thermoplastic composition, at least in the flexible wall portions thereof.
In another preferred embodiment, the container wall has a second wall region adjacent the included wall region set forth above, the second wall region defining the interior zone of the container and being (a) openable for receiving a product into the zone and (b) sealable for retaining the received product and for substantially preventing fluid flow communica-tion of the container interior with the container exterior through the second wall region.
In a highly preferred embodiment, the container wall is an open end bag formed of collapsible tubular sheet material.
Thus the wall may be a generally flat tube of flexible sheet material wherein the tube has first and second opposite ~ -longitudinal folds, a first one of the elongate sections of - sealed engagement extends from the first longitudinal fold toward the second fold and terminates to an opposite end of the first section spaced from the second fold, and a second one of the elongate sections of sealed engagement extends from the second lateral fold toward the first fold and terminates to an ,~; opposite end of the second section spaced from the first fold.
:~
The present container is highly suitable for forming sealed vacuum packages having good vacuum retention properites, without requiring presence of packaged product within the flow path nor dissipation of the product to seal the package.
Thus, the invention also provides a package including a container of the above described type, a product within the container, and gaseous composition at subatmospheric pressure within the container, said path being substantially sealed 3Q against fluid flow and including opposed wall portions in self-:
:.,, :
~1;
,~ ,~ .
) ~,~. -5-; ~, , . ,- . - . .. ,, . . .. . . .. . . . .: . , 1068~38 welding interengagement.
The path may be substantially free of product and pressure sealed, as desired. -In a preferred embodiment of the package, the container includes a sealed second wall region closely ad]acent a substantial portion of the product or article. In this embodiment the wall forms a skin about the product, thereby . . .
forming a vacuum skin package.
; The present invention also provides a process for vacuum packaging, which comprises:
(al receiving a product into the interior zone of a container of the above described type;
, (b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through the port to reduce -the gaseous pressure to subatmospheric pressure substantially *, throughout the container; and 1 (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure ~ithin the container.
As used herein "low permeability respecting water vapor, air and air components" means that the material or member thus characterized is sufficiently resistant to permeation such that subatmospheric pressure within ~ackages including a sheet or film of the material as an enclosing member is sub-stantially maintained for extended periods in gaseous environ-,y C~ ~ -6-.
.. ... i . :. :
. .. . . . . . .
.
ments normally encountered in storing and handling the packages. Typically, the gaseous environment is air at a pressure from about 740 to 780 mm. Hg absolute and at a temper-ature from about 0F. to about 120F. -,,1 .. :
i :
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~068238 The present invention will become more appar~nt frQm the followin~ ~etailed d~scription ta~en with the accompanying drawing whereill similar elements al-e identified ~ like numera]s thxoughout. .~ `
In the ~rawing:
FIG. 1 is a plan yie~ illus.trating a container having a check valve formed inte~rally with a wall the~eof and embodyin~ .
the present invention; ~ .
FIG. 2 is a partial perspectiYe Yiew illustrating corners 10 of a container interior wherein each. of.two secti~ns of sealed ; engagement of opposea container wall portions is coterminous with an interior corner and extends toward a generally opposite ~ -,,, ^ interior corner;
FIG. 3 is a plan view of an embodiment container ha~ing ~ 15 three generally parallel heat sealed sections;
.~ FIG. 4 is a plan view of a~-~ther embodiment container having slightly arcuate heat sealed sections wi~h a port dis-posed therebetween, . FIGS. 5-7 are plan views illustrating other containers . 20 embodying this invention;
, FIG. 8 is a perspective view generally illustrating a i package including the container of FIG. 3 and embodying the ~ package of the present invention in an aspect thereof;
'1 ` ~ `~ ' ; FIG. 9 is a plan view of the package;
FIG. lO is a sectional view taken along the line lO-lO
,.~g~
in FIG. 9, illustrating a ~tep in the preparation of the package with the check valve in open position for exhausting air; and }~ FIG. 11 is a sectional view similar to FIG. lO, showin~
30 the check valve in closed position.
~3 ~ ,~
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~ 7-: ` . . : .. . ', ~ . ' .
1(~682313 Referrin~ now to the drawing,especially FIG. 1 and ~I~. 2, illustxated therein ~s sealable con~ainer 10 for~ed by wall 12 which desirably is characterized ~ith low permea~ility respecting watex Yapor, aix and air components. The ~all includes wall 5 region 14 ha~in~ opposed fixst and second fle~i~le ~7all portions 16 and 18 proYided with elongate space~ apart aajacent sections 24 and 26 of sealed interengagement. Con~eniently, the wall ~ay be of heat seala~le material Wit~l the seals 24 and 26 pro-ided therein by any suita~le heat sealin~ means.
The container includes a check valYe 20 inte~ral with the wall and including openable port 22 disposed in wall region 14.
The port preferably is pro~ided by separate or separable unsealed portions of en~ edge 32 to which the wall region terminates.
The port and spaced sealed sections define a fluid flow path 15 schematically shown by arrows 28 which illustrate flow of fluid, typica~ly gaseous c~mposition, e.g., air, from interior -zone 30 of the container to the container exterior. The path or passage ~ extends from the container exterior adjacent the port to the i interior zone. The path is sealable against fluid flow by any 2a suitable means, e.g., pressureO It is found that the path is sufficiently pressure sealable that upon applicàtion of differ- -ential pressure effected by reducing gaseous pressure within the container to su~atmospheric pressure and e~posing the con-tainer exterior to atmospheric pressure, not only do opposed 25 flexibIe wall portions collapse into interengagement transversely 'i:
of the path, but also the path is thereby sufficiently sealed to maintain the subatmospheric pressure for extended periods.
Generally impro~ed Yacu~m packages may be prepared wherein ~i~ first transYerseend 34 of sealed section 24 is coterminous with i ~ 30 a first intexior surface portion of the container, thereby pro~
-~ ~idin~ corner 36 of the container intexior, and first transvers~
end 38 of sealed section 26 is coterminous with a second interior ~ ~ .
, ,.,~
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~ -8~
i .~ .
~: .. . . ... . .. . .. .
surface portion of th~ container, thereby proYiding corners 40 and 41 of the`con~àinex interior: Sealed ~ection 24 preferably e~tends fronl its *irst end generall~ toward corner 41 and sealed ~ection 26 pxeferabl~ extends frQm its first end generally toward corner 36. The sealea sections, which ~ay be'slightly arcuate or otherwise'generally strai~
are preferably genexally parallel each to the other r each section terminating to a second transvexse ena disposed pre-ferably diagonally from the first end of thè`other section, the longitudinal extents of the sections being preferably sufficient in length to provide a first elongate portion of '~he flow path, the path portion extending trans~ersely throughout from longitudinal edge 42 of sealed section 24 to opposite longitudinal edge 44 of sealed section 26.
As illustrated in FIG. 3, the container préferably includes third eilongate section 27 of sealed engagement of the wa~l portions 16 and 18t the third sealed section be~ng preferably generally parallel to sealed sections 24 and 26 ana having a first end preferably coterminous with a third interior surface portion of the container at corner 46, sealed sections 24 and 27 being spaced in opposite directions from sealed section 26 and providing a generally U-shaped turn portion of tha flow path about the second end thereof, as schematically illustrated by arrow 29. The longitudinal extent of sealed section 27 is ;2:5:~ pre~ferably sufficient in length to provide a second elongate portion of the flow path extending trans~ersely throughout from a longitudinal edge of the sealed section 27 to an opposite longitudlnal edge of sealed section 26.
~: 3Q ~' `'~' _ ' ..
~- ` ' `"
The containers illustrated in FI~. l and ~IG. 3 axe , generally found to be c~aracterized with an e~cellent balance of ease of Yacuumization and sealahility of the check ~alYe.
Two ox moxe of these containers ~ay be effectiYel~ fo~med into S Yacuum packages using simultaneous Yacuumizin~ thereof in the same chamber with ImproYements in eff~sienc~ relati~e to many heretofore known packaging techniques.
It is found that containers substantially identical to the container illustrated in FIG. l except not including at least two sp(aced apart adjacent sections of sealed engagement bordering transversely opposite sides of the flow path are not sufficiently sealable by differential pressure to suitably maintain a vacuum therein without employment of other means for sealing the flow path. Containers illustrated by FIG. 3 and having three or more seals disposed therein for providing a generally U-shaped turn portion ~f the flow path are gen~rally found to be even more effectively sealable trans~ersely of the flow path, as under a pressure differential resulting from vacuumizing and thereafter exposing the vacuumized container to air at atmospheric pressure.
Container lO may be of flattened tubular sheet material wherein opposed wall portions 16 and 18 are closely adjacent ~ one to the other. In general, for commercially acceptable ;~ vacuum packaging speeds using this construction it is critical 25 ~that the minimum distance transversely of the flow path be at least 3/4 inch and preferably at least l inch. For Yacuumizing at higher speed or obtaining higher package Yacuum using any -gi~en evacuation rate, the minimum distance trans~ersely of the flow path is at least l l/4 inches and preferably at least l 3/4 inches.
.
In e~bodiment cons~uct;~ns of the present container , . .
, . . ~ , ,~
1~)68Z38 wherein the ~all is of flattened tubular film ox sheet material with one ox morc lat~ral folds, at ieast one of the flo~ ~ath bordering seals prefera~ly extends from a fold, therehy improying sealability of the flow path.
S The present container ~a~ include one ox more arcuate sections of sealed interengagement as illustrated by slightly arcuate heat seals 48 and 5~ formed in generally parallel manner one to the other, thereby sealingly engaging opposed flexible wall portions 54 and 52 of bag 110 tFIG~ 4). The 10 exhaust port may be provided by forming the bag with separated or separable unsealed portions of end edge 56, which may be arcuate as shown and to which the wall region containing .
the arcuate seals terminates, or by pro~iding one or more slits through the bag wall as illustrated, for example, ~y :
15 slit 5g disposed intermediate the seals through flexible wall portion~54. In containers where-in a slit port is provid~d, end 56 may be sealed or open as desired.
Other containers embodying the present inYention are . illustrated by containers 210, 310, and 410 of FIG. 5, FIG. 6 20 and FIG. 7, respectively. These containers may be of the : construction set forth above with reference to the.containers of FIG. 1, FIG. 3 or FIG. 4, except as follows. Container 210 includes two elongate spaced apart adjacent sections 60 and 62, each being of sealed interengagement of opposed flexible wall 25 portions 64 and 66 which may be of one piece flattened tubular 1~ :
construction having lateral edge folds 68 and 70. The container preferably further includes generally L-shaped section 72 of sealed interengagement of the wall portions. The arm of the :~ L disposed transYersely of the container may be generally parallel ` 30 to seals 60 and 62, as sho~n, while the arm of the L disposed longitudinally of the hag is preferably spaced from lateral I, --1 1--- .
~, . ! . ' " ,, -- 106823~3 fold 68 a suitable distance,' e.g. aho~t 1 inch or more to pxoyide a defined flo~ path portion extending su~stantially to the'opposite end of the ~all. Bags thus formed;ma~ be found - ' to aid in substantially preYentin~ residual air pockets in S ,vacuum packages formed thexeof ~ith the ~all closely ab~ut packaged fresh red meat or other pro~ucts.
Container 410 is a vaxiation of container 10, shown in FIG. 1, wherein there is further pro~ided interrupted section 74 - - ' of sealed interengagement of flexible wall portions 16 and 18. `' Seal 74 extending longitudinally of the container or bag from genexally near an end of seal 26 to near opposite openable end 23 provides additional plural definitive flow path portions for aid , -' in evacuating gaseous composition from the container interior during Yacuumizing.
Container 310 (FIG. 6) illustrates an embodiment of the !~' invention wherein the container,,which may be a bag having , l .
openings at opposite ends 80 and 82, is provided with a ' , plurality of longitudinal seals 76 interengaging opposite flex- -ible wall portions 84 and 86. The seals extend from end edge , ~ 2~ 80 having a plurality of ports 88 to which plural flow paths ,' schematically indicated by arrows 90 terminate. Opposite laterally disposed seals 78 terminating to lateral folds of the ' ~ ' ~- container wall may be included ~or further aid in remo~ing air ',or other gaseous composition from the container interior.-- ' 5~ FIG. 8 illustrates package 92 including flexible container 10 '' (FIG.~3) which may~be o~ flexible thermoplastic film and bulky `a~rticle~94 within the container. Substantial portions of the ' -~' article may be closely adjacent portions of the container which -may~be~trAnsparent~as shown for xeady ~isibility of the article.
30~ The~pxessure;of ~le gaseous atmosphere within the container ~ '' is~belo~ the pres'sure on the container exterior, which may be ,~
. . , 106823~
normal atmospheric pres`sure,` and substantially below 760 mm. H~
absolute, if de ired' Th~ container interior may be at any suitable Yacuum leYel. In high ~acuum packa~ing application~
the pxessure ~ay be suhstantiall~ lo~, e.g. less than ~QQ mm. Hg S absolute, ~hile in lo~ Yacu~m applications the interior pressul-e may be, for example, about 720 to about 750 ~m. Hg. absolute.
The container,which may be of generally tubular construction sealed at one end, as for example by clip 96, includes wall portion 16 and oppositely adjacent wall portion 18. The opposed 10 wall portions adjoin one another at opposite edge folds which ;
may be provided by flattening the tubular wall in preparing the container.
The port and the spaced apart heat sealed sections define a fluid flow path extending from an interior zone of the container to the container exterior adjacent the port. The path i~Jdiagrammatically illustrated by the arrows in FIG. 9.
When the container is formed into a package as illustrated in FIG. 8, the path is substantially sealed against fluid flow by collapsed engagement of path-bordering portions of the 20 opposed flexible wall portions. As will become more apparent fxom the description below, the collapsed engagement is effected by applying relatively high pressure to the exterior of the ;~ package, the relative.-y high pressure being greater than the gaseous pressure within the container.
The package 92 may conveniently be formed using a tubular ~ film~container of generally rectangular shape when flattened, c~ and, after 1attening, proYiding heat sealed sections therein as~descrlbed~aboYe. An article to be packaged is inserted within an opened end of the container, which end is thereafter 30 sealed~as by clip 96 or other suitable means such as heat sealin~
or the like, the package 92 which is being formed now appearing as ~illustrated by FIG. 8 and FIG. 9.
-12n-The package heing formed is thereafter inserted into a Yacuum chambex or otKer suitable`zone which ma~ ~e`~aintained at a subatmospheric pressure of, fox example~ frQm a~out lO
to about l~0 ~m. H~ ahsolute`or more, there~ effecting S withdxawal of at least a poxtion of the air or ot~er gaseous environment fxom within the`container through t~e check valYe.
During va~uumi~ation and aix e~haustion or escape the check valve is opened by the greater gaseous pressure within the `"
CQntainer as shown in FIG. lO.
After the internal container pressure is reduced to a suitable value, e.g., from about 10 to about 100 mm. Hg., vacuumization is discontinued as, where a Yacuum chamber is used, by increasing the chamber pressure or removal of the package being formed from the chamber to a zone of higher ~-15 pressure which conveniently may be an environmént of air at standar~ or higher atmospheric pressure. The pressure d~ffer-I ential from without to within the container collapses the ¦ opposing wall portions 16 and 18 into substantially uniform ¦~ engagement resulting in seal-providing engagement of path-20 bordering portions of the opposed wall portions 16 and 18, as shown in`FIG. 11. The resulting package effective]y seals the contained article from air and other gaseous environments .~ ~
j ~ normally encountered in storing, distributing and di~splaying a vaxiety of articles, including b~t not limited to comestibles 2S and durable goods.
In an embodiment wherein the container is of heat-shrinkable sheet material, as may be desired, the package may next be heated to proYide a heat shrunk package. Heat shrinking is a suitable means for aiding in retention of the p~th seal which 3a is effec~ed-by the higher exterior pressure, as may be desired in rough handling applications.
., .~: ~ , ~ . , ` .
,, :
1068Z3~3 The sheet material o~ the container ~ay be o any suitable composition, including paper, metal (e~`g. aluminu~ ~oil~ xesins - ~e~g~ thex~opla~tics) and the like. ~uitahle`the~mo~lastic compositions incl~de for example, poly~ers of ethylene, propylene, - 5 yiny-lidene chloride, ~inyl chIoride, interpolymer~ thereof with other po]ymerizable ~onomers, block pol~mers thereof, graft polymers thereof, ethylene Yinyl alcohol copolymers, and the like. Laminates of two or,more plies are also suitable sheets from which the container and package may be prepared. Suitable laminates include, for example, laminated films or sheets including a polyethylene or polypropylene ply with an adjacent saran ply. A preferred laminate includes two plies of poly-ethylene or an ethylene copolymer (e.g. ethylene ~inyl acetate copolymer) with a saran ply therebetween.
The term saran is applied to a family of thermoplastic resinsj~viz, vinylidene chloride-~polymers, and copolymer~ of vinylidene chloride with other monomers such as -Yinyl chloride, acrylonitrile, methyl methacrylate, acrylates, acrylate esters, vinyl acetate, and the like. Copolymars of Yinylidene chloride 20 with other monomers are generally described in terms of the weight ratio of the monomer units in the ~copolymer Saran, by ` definition, has at least 50 percent Yinylidene chloride.
The inner surfaces of the container wall may be adapted for bonding one to another as by forming the wall of adhesive 25 ~material such as adhesive ethylene vinyl acetate copolymer (EYA) or ; providing a coati~g there~f on a substrate of other packaging material. EYA and other self-welding wall materials are eminently suitable.
The container component of the present package ~ay have an~ suitable wall ~ickness. Films ha~in~ thicknesses of from a~out 0-.5 t-o about 10 mils axe hi~hl~ suita~le.
Although the above description of the container has been , :: ~
~ -14-given principally with reference to a bag foxmed o~ ~lattened tubular sheet materic~l, pouches and other container f~ms are also within the scope o~ the present inyention. It is ~nder-stood that the opposed flexible wall portions of the present container-~ay ~e foxmed of any suitable constr~ction, including a single sheet or fil~ folded on itself ana pro~ided ~ith any suitable seal, e~g. a heat seal, along an end opposite the fold, two superimposed sheets or films heat or otherwise sealed at opposite ends thereof, and the like.
lOPxactice of the present inYention is further illustrated by the following non-limiting examples. The bags used in the `
exa~ples were prepared substantially as next set forth.
A tubular composite laminate ha~ing a transparent flexible wall was prepared by co-extruding through appropriate annular -die lands an inner layer of ethylene Yinyl acetate copolymer (EVA), an intermediate layer of a saran copolymer formed Df about 85 percent by weight of vinylidene chloride units and about 15 percent by weight of vinyl chloride units, and an outer layer of ethylene vinyl acetate copoly~er (EYA~. The co-extru~ion was effected using well known blow extrusion procedures therefor. ~he laminate wall was about two and one half mils in thicknes9 with the various layers having the following approximate thicknesses: the inner EVA layer, one half mil; the intermediate saran layer, one and one half mils;
25~ and the outer EVA layer, one half mil. The inside diameter of the tube was a~out 9 inches. The tubular laminate was passed through the nip of a pair of cooling rolls thereby proYiding a flattened tube about 14 inches in width haYing transYersely opposite~ lateral folds disposed longitudinally of the tube.
30~ - A plurality o~ gene~ally rectangular bags substantially ~ -as illustrated in FIG. 3 wexe proYided by transvexsely s~ering :: :
~ ~ .
~, ~; -15-~ ~ .
the tube alon~ widths thereof spaced about 3Q inches apart . lon~itudinally of the~`tu~e,:~ollo~ed~ ~y proYidin~ eàch seyered :: tube'seg~ent with a set of three elon~ate'transYerse'~enerally strai.ght heat seals a~out 1/16 inch in ~idth'adjacent an open end thexeof using well known heat sealing pxocedures.
EX~mple 1 Referring to FIG. 3, the distance longitudinally of one of the bags from the intermediately disposed heat seal 26 to ~ each of adjacent heat seals 24 and 27 was about 1 inch. The 10 distance i.s referred to hereinafter as X. This bag is referred to hereinafter as Bag A. Each of these seals was about 13 1/4 inches in length, extending from a side fold of the bag and ::
termina'ting to an end disposed at a distance Y of a~out 3/4 ineh from an opposite side fold, as measured generally parallel 15 to the other heat seals. The seal disposed closest to the ' .
nearest~end of the bag was space'd therefrom at a distanc~ of not more than about one inch.
The loading end of the bag, i.e. the end disposed further ~`: from the heat seals, was opened and a top butt beef portion ~ 20 having a m~nimum diameter of approximately 4 inches was inserted therethrough and received into the bag interior zone extending generally from near the loading end to near the opposite ed~e of heat seal 27 (FIG. 3). Thereafter, a region o~ the bag adja~cent;the loading end was provided with a substantially air-tight:seal using a~bag gathering and clip crimping method substantially as~disclosed in U. S. Pat. No. 3,11i,794 to Spolino.
:The~bag~now~having: one unsealed end and the beef portion therein was placed:~in a vacuumizing chamber e~uipped with a si~ht glass, after~which. air was remoYed from the chamber interior in 3~ su icient amount l-sing a Yacuum pump to decrease thè internal chamber:pressure to about 27 inche5 Hg vacuum wi~lin about ,~, . . . ..... .. ....
30 seconds, the chamber pressure quickly decreasin~ to about 21 inches ~Ig yacuum ~nd moxe sl~wly therea~t~x. The Yacuumizing included ~aintainin~ the appxoximate 27 inch Hg yac~ for about 10 seconds. Obser~ation~ made durin~ the ~acuumizing period showed that the interior and flo~ path zones o~ the ha~
initially expanded as the cha~er pressure decreased and thereafter contracted, shbwin~ that air was remo~ed from the bag interior through the port proYided by the openable ~ag end opposite the clipped end of the bag. After the vacuu~izing period, the chamber was opened, exposing the loaded ba~ to room air at approximately 30 inches Hg absolute pressure and resulting in portions of the bag wall collapsing into contact with the top butt and portions of the wall intermediate the flow path defining heat seals collapsing into sealing wall-to-wall in~rengagement-Within a brief period thereafter, the resulting seaLedvacuum package was placed in a bell jar, which thereafter was slowly evacuated until the bag interior expanded to an extent such that substantial portions of the bag wall were released 20 fromPcontact with the top butt. Obseryation of a vacuum guage provided on the bell jar showed that the ohser~ed extent of bag wall release occurred at a bell jar Yacuum o~ about 1 in. Hg.
For measurement purposes the vacuum achieYed in the package of thi-s example was taken as 1 in. Hg., i.e. the bell jar end 25 point vacuum.
The vacuum package made using Bag A is of good Yacuum retention in applications where rough handling is aYoided.
For rough handling, better Yacuum retention results hy pro-viding a further séal, for exa~ple, a high stren~th heat seal, 30~transver~ely of the ~low path after Yacuumization. The vacuumized bag may be exposed to at~ospheric pressure with :
good vacuum rete~ition for relativelv lon~ periods prior to fur~her sealing for rough handling applications.
~, `` 1068Z38 Ex`amples 2 and 3 Th.e`p~ocedure `o~ Example 1 was~repeated using t~o ~ags referred to hereinafter as Bag ~ and Bag C. These bags ~ere substantially the same :as Bag A except that at.least one of ~.
the length. and s.pacing of the heat ~eals 24, 26, and 27 (FIG. 3 were Yari.ed such that the~seal~to-seal distances X and the seal-to-fold distances Y were appxoximately as shown ~elow: ..
BAG X (inch~s? - Y tinches) Bag B l 7/8 ..
Bag C l l/8 l l/4 The results were substan~ially the same, Bags B and C
resulting in packages with approximately l inch Hg Yacuum as . measured using the belljar technique set forth in EXample l.
. ` Examples 4 and 5 j 15 The procedure of Example l was again repeated using two bags r~erred to hereinafter as(:Bag D and Bag E. These hags were substantially the same as Bag A except that the length and spacing of the heat seals 24, 26 and 27 (FIG. 3) were varied such that the seal-to-seal distances X and the seal-to-~`
fold distances Y were approximately as shown below:
BAG X (inches) Y (inches) Bag D l l/4 2 l/4 . , ~ . .
Bag E l l/4 2 l/4 The results:were even:better, Bag D resulting in a 5:~pac~age w1th about 2 inches Hg Yacuum and Bag E resulting in a package~:with between l and 2 inches Hg Yacuum, as determined `.
by~the~bell jar technique set forth in Example l.
30 ~
; -18-.
~x~n~les_ 6 and 7 The procedure of Example l was again repeated using two bags referxed to hereinaftex as Bag F and ~a~ ~. These ba~s were substantially the same as Bag ~ except that the length and spacin~ of the heat seals 24, 26 and 27 ~IG. 3~ were varied such that the seal~to-seal distances X and the seal-to-fold distances Y were approximately a~ shown below:
BAG X (inches) Y (ihches) .
Bag F 2 l/8 l l/2 Bag G 2 l/4 2 3/8 The results were even better than the results o~tained for Bag D, Bag F resulting in a vacuum package with about 4 inches Hg vacuum and Bag G resulting in a ~acuum package with about 7 inches Hg vacuum, as determined by the bell jar technique of Example l.
~ Examples 8 through 10 The procedure of Example l was again repeated using three bags referred to hereinafter as Bag H, Bag I, and Bag J. These bags were generally the same as Bag A except that the heat seals 24, 26, and 27 (FIG. 3) were varied such that the distances Xl ~: and X2 f~om the intermediately disposed heat seal 26 to one of the two adjacent heat seals 24 and 27 and to the other one of ~: the heat seals 24 and 27, respectively, and the distance Y were -:
approximately as follows:
B~ X1 (inches) ~ (inches) - Y (inches) Bag H 2 l/4 l 3/4 l l/2 .. -.
Bag I 2 l/4 l 3/4 3 Bag J 2 l/4 l 7/8 3 These bags were found eminentl~ suitable for vacuum ::: :
packa~ing, Bag H resulting in a good ~acuum package wi.th about
2 in:ches Hg vacuu~, Bag I xesulting in a better Yacuum package with about 4 inches Hg ~acuum, and Bag J resulting in an .
~ 19- .
106823~ `
even better Yacuum pac~age wi~l abollt 5 inches Hg Yacuum, as detexmined by the bell jar technique of E~ample 1.
E~amples ll thro~gh l5 ~-The proceduxe o~ ~xample l ~as again repeated using 5 five bags xeferred to hereinafter as Ba~ K, Bag L, Ba~ M, Bag N, and Bag ~. Th~se ba~s were substantially the same as Bag A except that the heat seals 24, 26, and 27 (FIG. 3) were varied such that the dîstances X and Y were as shown below:
B X -(inches)Y (inches~
Bag K l/2 l/4 Bag L l/2 3/8 Bag M l/2 3~4 Bag N 1j2 ~ l/2 ; 15Bag O l/2 l 1/4 One of the heat seals 24, 26 and 27 (FIG. 3~ of Bag K
suddenly unsealed during the time of rapidly decreasing pressure in the vacuumizing period, thereby reducing the ease of sealing the flow path of the bag. The package formed using Bag L
included air under essentially no partial ~acuum. Bag M, Bag N and Bag O each containing air under slight?y more than zero and substantially less than one inch Hg ~acuum as measured by the bell jar technique of Example l, while suitable for packaging applications requiring not more than minimal vacuum ~were judged unsuitable for high speed commercial Yacu~m , packaging of air-degradable products.
` Example 16 Bags o the present inYention were prepared substantially ; as set forth in the aboYe description immediately preceding Example l except that, prior to flattening,the inside diameter of the tube was about 6 l/2 inches. After flattening, se~ering ~ : ~
and pro~iding heat seals 24, 26 and 27 (FIG. 3) the generally rectangular bags measured about 10 inches in width and about -~0-10~8238 20 inches in length. The distance X from heat seal 26 to each of seals 24 and 27 ~as a~out one inch, each of the seals measuring about 1/16 inch'in thickness longitudinally of the bag and e~tendiny about 9 inches ,fxo,m the coIrespondin~ side fold and terminatin~ to a seal end disposed at a distance Y
of about one inch fro~ the'opposite'si~e fold, as measured generally parallel to the other heat seals.
These bags were tested for suitability in vacuum packaging ; fresh red meat using the following procedure except where otherwise indicated. A relatively fresh beef sirloin tip having minimum diameter greater than one inch waB inserted into each bag through an end of the bag opposite the end containing ' the three generally parallel hea* seals followed by proYiding an air~tight seal nea~ the loading end as in Example 1.
Thereafter the bags were chamber vacuumized to a chamber pressure I of abo~t 29 inches Hg vacuum which was maintained for a ~rief ; period, followed by applying atmosphéric pressurç to the bag ~ exterior,s through a valve provided with the cha,mber. The bags ,l were observed to expand, contract and collapse into contact 2a with the meat substantially as in Example 1. Thereafter, with ~, the exception of one bag, each of the various bags were heat '1~'.
sealed transversely of its flow path from one to another of ,~ its parallel heat seals using well known heat sealing procedures.
,, ~
One of the packages was heat shrunk by immersing the bag in hot water for a brief period effective for shrinkage. The vacuum level in each bag was estimated from observations of the extent of bag collapse about the packaged meat.
Observations of the meat vacuum packaged in each of the bags made at the elapsed tLmes indicated below showed that the ba~s were eminentl~ suitable in meat color retention pxoperties ; for extended periods. Data for these bags appears in Ta~le I
f~ hereof.
', -21-` ` `` ~068238 TABLE 1 ~
APP~OXI~L~TE APPROXIMATE POST-VACUUMIZING
BAG VAC W M ` STOI~GE TIME . `COLOR ~REAq~MENT
~ . . . . . . . . ......... ..
AA ~odexate ~ `8 to 24 h~uxs 8.5 Heat sealed transYersely of flow path 13B 2~0derate --do-- 8.5 --do--CC la~Y --do-- 7.5 --do--DD moderate 8 to 24 hours 8 heat shrunk flow path region EE --do-- --do-- 7.5 heat sealed transversely of flow path FF --do-- --do-- 7.5 --do--GG moderate 10 days 8 --do--HH --do-- 10 days 8--8.5 --do-- `:
, ..
NOTE: In the abo~e table, moderate Yacuum is ahout 2 inches Hg or more vacuum and low vacuum is fro~:.a~,Jout 1 to less than 2 Inches Hg vacuum.
Thefnumerical color values w~re assigned using a well-known color rating scale for fresh red meat whereln better color is indicated by higher numbers, 7 to 10 bèing generally accepted in the art as commercially suitable. Each of the packaged meat portions was severed from a larger portion of 25~ approximately double its size. The residual sub-portions were ;vacuum packaged using conventional procedures for paired color c mparison~at the same elapsed times shown in Table I. The observed~colors were substantially the same for the two meat "`' ~ portions~ of each pair. ~
The~walls~of~the~cQntainers in Examples 1 through 16 supra were characterlzed~with 10w~permeability respecting water vapor, air and air co~pon~ents.
~068Z38 In other embodiments, the sealable container described above may be provided with only one section of sealed engagement of the first and second wall portions.
In greater detail, the container may be substantially the same as container 10 (see FIGS. 1 to 3 and the correspond- -ing verbal description) with only one of the seal sections 24, 26 and 27 included. In other embodiments of such containers of this aspect, the container may be substantially the same : `
as container 110 (see FIG. 4 and its accompanying verbal description) with only one of the seal sections 48 and 50 present, substantially the same as container 410 (see FIG. 7 and the verbal description given above with reference thereto) with only one of the seal sections 24 and 26 present, with or without the seal sections 74, and variations of these latter `
two embodiments wherein the transverse ,, 'I .
~; , i '.
, ~
~ 22a-106823~
seal or the end edge 56 is substantially straight. Preferably tlle sole path-defining seal sec~ion is disposed proximatc the port, e~g. spaced from t}le port about 0.001 to about one inch or a distance equal to about 0.01 to abou~ lO percent of a length of the container. Especially 5 preferred in this aspect are containers which are open end bags formed ~' of collapsible tubular sheet ~aterial, preferably bags in fla~tened tubular form.
The containers of this aspect are highly suitable for forming other embodiments of the present pac~age for applications wherein suitable post-evacuation.sealing of the fluid flow path may be effected without need for ~ore than one path-defining sealed section.
In another aspect, the present process for vacuum packaging may be carried out using containers of the latter described aspect of th~
present container.
It is understood that the foregoing detailed descript,ion is given merely byiway of illustrationland that numerous variations may be made therein ~ithout departing from the spirit or scope of the present invention.
:.
~ 22b-: :
~ 19- .
106823~ `
even better Yacuum pac~age wi~l abollt 5 inches Hg Yacuum, as detexmined by the bell jar technique of E~ample 1.
E~amples ll thro~gh l5 ~-The proceduxe o~ ~xample l ~as again repeated using 5 five bags xeferred to hereinafter as Ba~ K, Bag L, Ba~ M, Bag N, and Bag ~. Th~se ba~s were substantially the same as Bag A except that the heat seals 24, 26, and 27 (FIG. 3) were varied such that the dîstances X and Y were as shown below:
B X -(inches)Y (inches~
Bag K l/2 l/4 Bag L l/2 3/8 Bag M l/2 3~4 Bag N 1j2 ~ l/2 ; 15Bag O l/2 l 1/4 One of the heat seals 24, 26 and 27 (FIG. 3~ of Bag K
suddenly unsealed during the time of rapidly decreasing pressure in the vacuumizing period, thereby reducing the ease of sealing the flow path of the bag. The package formed using Bag L
included air under essentially no partial ~acuum. Bag M, Bag N and Bag O each containing air under slight?y more than zero and substantially less than one inch Hg ~acuum as measured by the bell jar technique of Example l, while suitable for packaging applications requiring not more than minimal vacuum ~were judged unsuitable for high speed commercial Yacu~m , packaging of air-degradable products.
` Example 16 Bags o the present inYention were prepared substantially ; as set forth in the aboYe description immediately preceding Example l except that, prior to flattening,the inside diameter of the tube was about 6 l/2 inches. After flattening, se~ering ~ : ~
and pro~iding heat seals 24, 26 and 27 (FIG. 3) the generally rectangular bags measured about 10 inches in width and about -~0-10~8238 20 inches in length. The distance X from heat seal 26 to each of seals 24 and 27 ~as a~out one inch, each of the seals measuring about 1/16 inch'in thickness longitudinally of the bag and e~tendiny about 9 inches ,fxo,m the coIrespondin~ side fold and terminatin~ to a seal end disposed at a distance Y
of about one inch fro~ the'opposite'si~e fold, as measured generally parallel to the other heat seals.
These bags were tested for suitability in vacuum packaging ; fresh red meat using the following procedure except where otherwise indicated. A relatively fresh beef sirloin tip having minimum diameter greater than one inch waB inserted into each bag through an end of the bag opposite the end containing ' the three generally parallel hea* seals followed by proYiding an air~tight seal nea~ the loading end as in Example 1.
Thereafter the bags were chamber vacuumized to a chamber pressure I of abo~t 29 inches Hg vacuum which was maintained for a ~rief ; period, followed by applying atmosphéric pressurç to the bag ~ exterior,s through a valve provided with the cha,mber. The bags ,l were observed to expand, contract and collapse into contact 2a with the meat substantially as in Example 1. Thereafter, with ~, the exception of one bag, each of the various bags were heat '1~'.
sealed transversely of its flow path from one to another of ,~ its parallel heat seals using well known heat sealing procedures.
,, ~
One of the packages was heat shrunk by immersing the bag in hot water for a brief period effective for shrinkage. The vacuum level in each bag was estimated from observations of the extent of bag collapse about the packaged meat.
Observations of the meat vacuum packaged in each of the bags made at the elapsed tLmes indicated below showed that the ba~s were eminentl~ suitable in meat color retention pxoperties ; for extended periods. Data for these bags appears in Ta~le I
f~ hereof.
', -21-` ` `` ~068238 TABLE 1 ~
APP~OXI~L~TE APPROXIMATE POST-VACUUMIZING
BAG VAC W M ` STOI~GE TIME . `COLOR ~REAq~MENT
~ . . . . . . . . ......... ..
AA ~odexate ~ `8 to 24 h~uxs 8.5 Heat sealed transYersely of flow path 13B 2~0derate --do-- 8.5 --do--CC la~Y --do-- 7.5 --do--DD moderate 8 to 24 hours 8 heat shrunk flow path region EE --do-- --do-- 7.5 heat sealed transversely of flow path FF --do-- --do-- 7.5 --do--GG moderate 10 days 8 --do--HH --do-- 10 days 8--8.5 --do-- `:
, ..
NOTE: In the abo~e table, moderate Yacuum is ahout 2 inches Hg or more vacuum and low vacuum is fro~:.a~,Jout 1 to less than 2 Inches Hg vacuum.
Thefnumerical color values w~re assigned using a well-known color rating scale for fresh red meat whereln better color is indicated by higher numbers, 7 to 10 bèing generally accepted in the art as commercially suitable. Each of the packaged meat portions was severed from a larger portion of 25~ approximately double its size. The residual sub-portions were ;vacuum packaged using conventional procedures for paired color c mparison~at the same elapsed times shown in Table I. The observed~colors were substantially the same for the two meat "`' ~ portions~ of each pair. ~
The~walls~of~the~cQntainers in Examples 1 through 16 supra were characterlzed~with 10w~permeability respecting water vapor, air and air co~pon~ents.
~068Z38 In other embodiments, the sealable container described above may be provided with only one section of sealed engagement of the first and second wall portions.
In greater detail, the container may be substantially the same as container 10 (see FIGS. 1 to 3 and the correspond- -ing verbal description) with only one of the seal sections 24, 26 and 27 included. In other embodiments of such containers of this aspect, the container may be substantially the same : `
as container 110 (see FIG. 4 and its accompanying verbal description) with only one of the seal sections 48 and 50 present, substantially the same as container 410 (see FIG. 7 and the verbal description given above with reference thereto) with only one of the seal sections 24 and 26 present, with or without the seal sections 74, and variations of these latter `
two embodiments wherein the transverse ,, 'I .
~; , i '.
, ~
~ 22a-106823~
seal or the end edge 56 is substantially straight. Preferably tlle sole path-defining seal sec~ion is disposed proximatc the port, e~g. spaced from t}le port about 0.001 to about one inch or a distance equal to about 0.01 to abou~ lO percent of a length of the container. Especially 5 preferred in this aspect are containers which are open end bags formed ~' of collapsible tubular sheet ~aterial, preferably bags in fla~tened tubular form.
The containers of this aspect are highly suitable for forming other embodiments of the present pac~age for applications wherein suitable post-evacuation.sealing of the fluid flow path may be effected without need for ~ore than one path-defining sealed section.
In another aspect, the present process for vacuum packaging may be carried out using containers of the latter described aspect of th~
present container.
It is understood that the foregoing detailed descript,ion is given merely byiway of illustrationland that numerous variations may be made therein ~ithout departing from the spirit or scope of the present invention.
:.
~ 22b-: :
Claims (34)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A sealable container which comprises: (a) a wall including a wall region having opposed first and second flexible wall portions;
(b) a check valve integral with the wall and including an openable port disposed in said wall region; and (c) an elongate section of sealed engagement of the first wall portion with the second wall portion;
said first ant second wall portions having opposed interior faces that are self-welding such that when the container is subjected to heat, the opposed faces bond to one another to close off the check valve and render the section of sealed engagement indistinguishable from the surrounding walls, said port and sealed section defining a fluid flow path extending from the container exterior adjacent the port to an interior zone of the container, said path being substantially sealable against fluid flow, said wall being characterized with low permeability respecting water vapor, air, and air components.
(b) a check valve integral with the wall and including an openable port disposed in said wall region; and (c) an elongate section of sealed engagement of the first wall portion with the second wall portion;
said first ant second wall portions having opposed interior faces that are self-welding such that when the container is subjected to heat, the opposed faces bond to one another to close off the check valve and render the section of sealed engagement indistinguishable from the surrounding walls, said port and sealed section defining a fluid flow path extending from the container exterior adjacent the port to an interior zone of the container, said path being substantially sealable against fluid flow, said wall being characterized with low permeability respecting water vapor, air, and air components.
2. The container of claim 1 including at least two elongate spaced apart adjacent sections of sealed engagement of the first wall portion with the second wall portion.
3. The container of claim 2 wherein a first transverse end of a first one of said sections of sealed engagement is coterminous with a first interior surface portion of the container, thereby providing a first corner of the container interior, and a first transverse end of a second one of said sections of sealed engagement is coterminous with a second interior surface portion of the container, thereby providing a second corner of the container interior, said first section extending from its first end generally toward said second corner, and said second section extending from its first end generally toward said first corner.
4. The container of claim 3 wherein each of said first and second sealed sections extends from its first transverse end in generally parallel manner to the other and terminates to a second end of the section, each of said second ends being disposed diagonally of the first end of said another section, the longitudinal extents of the sections being sufficient in length to provide a first elongate portion of the flow path, said path portion extending transversely throughout the path portion from a longitudinal edge of said first sealed section to an opposite longitudinal edge of said second sealed section.
5. The container of claim 4 wherein said sealed sections extending from said transverse ends are generally straight.
6. The container of claim 5 wherein said sealed sections axe slightly arcuate.
7. The container of claim 3 including a third elongate section of sealed engagement of the first wall portion with the second wall portion, said third sealed section being generally parallel to said first and second sealed sections, said third sealed section having a first end coterminous with a third interior surface portion of the container, said first and third sealed sections being spaced in opposite directions from the second sealed section and providing a generally U-shaped turn portion of the flow path about said second end of said second section.
8. The container of claim 7 wherein the longitudinal extent of said third sealed section is sufficient in length to provide a second elongate portion of the flow path, said second path portion extending transversely throughout from a longitud-inal edge of said third sealed section to an opposite longitud-inal edge of said second sealed section.
9. The container of claim 7 wherein said first, second and third sealed sections are generally straight.
10. The container of claim 1 or 2 wherein said wall portions are of thermoplastic composition.
11. The container of claim 2 wherein the wall is an open end bag formed of collapsible tubular sheet material.
12. The container of claim 2 wherein the wall is a generally flat tube of flexible sheet material, said tube having first and second opposite longitudinal folds, a first one of said elongate sections of sealed engagement extends from said first longitudinal fold toward said second fold and terminates to an opposite end of said first section spaced from said second fold, and a second one of said elongate sections of sealed engagement extends from said second lateral fold toward said first fold and terminates to an opposite end of said second section spaced from said first fold.
13. The container of claim 1, 2 or 12 wherein said wall region terminates to an end edge and the openable port is an unsealed portion of said end edge.
14. The container of claim 1, 2 or 12 wherein said path is pressure sealable.
15. The container of claim 12 wherein said first and second elongate sealed sections are generally parallel each to the other, the longitudinal extents of the sections being sufficient in length to provide a first elongate portion of the flow path, said path portion extending transversely throughout the path portion from a longitudinal edge of said first sealed section to an opposite longitudinal edge of said second sealed section.
16. The container of claim 15 wherein said wall region terminates to an end edge and the openable port is an unsealed portion of said end edge, said sealed sections being generally parallel to said end edge.
17. The container of claim 16 including a third elongate section of sealed engagement of the first wall portion with the second wall portion, said third sealed section being generally parallel to said first and second sealed sections, said third sealed section extending from said first fold, said first and third sealed sections being spaced in opposite directions from the second sealed section and providing a generally U-shaped turn portion of the flow path about said second end of said second sealed section.
18. The container of claim 17 wherein the longitudinal extent of said third sealed section is sufficient in length to provide a second elongate portion of the flow path, said second path portion extending transversely throughout from a longitud-inal edge of said third sealed section to an opposite longitud-inal edge of said second sealed section.
19. The container of claim 2 wherein the wall has a second wall region adjacent said included wall region, said second wall region defining said interior zone of the container and being (a) openable for receiving a product into said zone and (b) sealable for retaining the received product and for sub-stantially preventing fluid flow communication of the container interior with the container exterior through said second wall region.
20. The container of claim 12 wherein the wall has a second wall region adjacent said included wall region, said second wall region defining said interior zone of the container and being (a) openable for receiving a product into said zone and (b) sealable for retaining the received product and for substantially preventing fluid flow communication of the con-tainer interior with the container exterior through said second wall region.
21 A package comprising the container of claim 1, a product within the container, and gaseous composition at sub-atmospheric pressure within the container, said path being substantially sealed against fluid flow and including opposed wall portions in self-welding interengagement.
22. A package comprising the container of claim 2, a product within the container, and gaseous composition at sub-atmospheric pressure within the container, said path being substantially sealed against fluid flow and including opposed wall portions in self-welding interengagement.
23. A package comprising the container of claim 11, a product within the container and gaseous composition at sub-atmospheric pressure within the container, said path being substantially sealed against fluid flow and including opposed wall portions in self-welding interengagement.
24. A package comprising the container of claim 12, an article within the container with the second wall region closely adjacent a substantial portion of the article, and gaseous com-position at subatmospheric pressure within the container, said path being substantially sealed against fluid flow and including opposed wall portions in self-welding interengagement.
25. A package comprising the container of claim 19, an article within the container with the second wall region closely adjacent a substantial portion of the article, and gaseous com-position at subatmospheric pressure within the container, said path being substantially sealed against fluid flow and including opposed wall portions in self-welding interengagement.
26. A package comprising the container of claim 20, a product within the container, and gaseous composition at sub-atmospheric pressure within the container, said path being substantially sealed against fluid flow and including opposed wall portions in self-welding interengagement.
27. The package of claim 21 or 26 wherein the path is substantially free of product.
28. The package of claim 21, 22 or 23 wherein the path is pressure sealed.
29. The package of claim 24, 25 or 26 wherein the path is pressure sealed.
30. A process for vacuum packaging Which comprises (a) receiving a product into the interior zone of the container of claim 1, 2 or 11;
(b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through said port to reduce the gaseous pressure to subatmospheric pressure substantially throughout the container; and (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure within the container.
(b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through said port to reduce the gaseous pressure to subatmospheric pressure substantially throughout the container; and (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure within the container.
31. A process for vacuum packaging which comprises (a) receiving a product into the interior zone of the container of claim 12, 19 or 20;
(b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through said port to reduce the gaseous pressure to subatmospheric pressure substantially throughout the container; and (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure within the container.
(b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through said port to reduce the gaseous pressure to subatmospheric pressure substantially throughout the container; and (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure within the container.
32. The container of claim 2 wherein the wall is of heat-shrinkable material.
33. A process for vacuum packaging which comprises (a) receiving a product into the interior zone of the container of claim 32;
(b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through said port to reduce the gaseous pressure to subatmospheric pressure substantially throughout the container; and (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure within the container;
(d) and thereafter heating the container wall to shrink the wall tightly about the product.
(b) placing the container with the received product in a subatmospheric pressure zone and exhausting gaseous composition from within the container through said port to reduce the gaseous pressure to subatmospheric pressure substantially throughout the container; and (c) while the interior container pressure is reduced, sealing the path by applying relatively high gas pressure on the exterior of the container to collapse a first path-bordering portion of one of said wall portions into self-welding sealing engagement with a second path-bordering portion of the other wall portion, said exterior gas pressure being high relative to the gas pressure within the container;
(d) and thereafter heating the container wall to shrink the wall tightly about the product.
34. A package comprising the container of claim 32, a product within the container and gaseous composition at subatmospheric pressure within the container, said path being substantially sealed against fluid flow, the wall being heat-shrunk closely about the product.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52838674A | 1974-11-29 | 1974-11-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1068238A true CA1068238A (en) | 1979-12-18 |
Family
ID=24105479
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA233,760A Expired CA1068238A (en) | 1974-11-29 | 1975-08-19 | Container, vacuum package, and packaging process |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1068238A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5701996A (en) * | 1994-05-17 | 1997-12-30 | Idemitsu Petrochemical Co., Ltd. | Snap-fastener bag |
-
1975
- 1975-08-19 CA CA233,760A patent/CA1068238A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5701996A (en) * | 1994-05-17 | 1997-12-30 | Idemitsu Petrochemical Co., Ltd. | Snap-fastener bag |
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