CA1192167A - Easy open package having a reclosable feature - Google Patents

Easy open package having a reclosable feature

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Publication number
CA1192167A
CA1192167A CA000405609A CA405609A CA1192167A CA 1192167 A CA1192167 A CA 1192167A CA 000405609 A CA000405609 A CA 000405609A CA 405609 A CA405609 A CA 405609A CA 1192167 A CA1192167 A CA 1192167A
Authority
CA
Canada
Prior art keywords
bag
fold
seal
portions
dead
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
Application number
CA000405609A
Other languages
French (fr)
Inventor
Stephen F. Compton
Milton A. Howe, Jr.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cryovac LLC
Original Assignee
WR Grace and Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by WR Grace and Co filed Critical WR Grace and Co
Application granted granted Critical
Publication of CA1192167A publication Critical patent/CA1192167A/en
Expired legal-status Critical Current

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Abstract

AN EASY OPEN PACKAGE HAVING A
RECLOSABLE FEATURE

Abstract of the Disclosure A pouch or bag constructed from multi-layer thermoplastic film for packaging cheese, luncheon meat and the like. Around the mouth of the bag the lip is folded inwardly, the mouth flattened, and a transverse seal is applied across the bag between the fold line and the folded under edge to close the bag in a seal in which a portion of the outer surface of the bag is sealed to itself thereby providing an easy open seal. Along one-half of the mouth a dead fold element is enclosed within the fold which, when bent, aids in closing the package.

Description

FIELD OF INVENTION
. . _ Thls invention relates to packages for cheese, luncheon meant and the like. Specifically, the invention relates to an easy open seal for such packages and further relates to means to close such packages once they are opened.

BACKGROUND

Cheese, luncheon meat, and similar products and commodities are packaged today in a thermoplastic film which is overwrapped about the article to be packaged and the film is heat sealed to itself to form closure seams.
After the package is heat sealed, it is a problem to open the package without destroying the package and leaving it unsuitable for further use. The problem is compounded because the films for packaging such products as cheese and luncheon meat should be strong and abuse resistant and have desirable gas transmission properties yet at the same time be capable of being opened without destroying the package. Thus, it is a principal object of this invention to provide a closure and seal configuration which is easily opened hy a relatively small opening force and does not destroy the package.
Numerous seal configurations have been proposed in the past which employ easy open features. For example, U.S. Patent 2,963,396 shows an opening and separating feature for a thermoplastic film package wherein a gusset type fold provides grippable pull-apart tabs. U.S. Patent No. 3,536,501 which issued on October 27, 1970 to W. A. Work shows a package in which the edge of the closure flap is folded over so that the outer film layer is sealed to itself. French Patent No. 1,331,100 which was filed January 22, 1962 naming Mme. Beernaert (formerly Germaine Malard) as inventor shows a package with a closure seal in which the edges of the mouth of the receptacle are folded outwardly and then a heat seal is placed through the four layers of film. U.S. Patent No. 3,655,503 r.~

which issued on April 11, 1972 to Hugh E. Stanley and George M. Tbkos shows a package closure seal in which multilayer Eilms are sealed togeth~r and when pulled a~art to cpen the package the outer layer of one film ruptures and delaminates only in the seal area. Another object of the present invention is to provide a package and seal configuration improved over the aforementione~
and other presently available designs.
Another problem encountered in packages for cheese and luncheon meat is that often ~nly a portion of the product is consumed at one time and it is desirable that the package be effectively reclosed ~o protect the remaining portion. Numerous reclosure elements have ~een proposed in the prior art including those disclosed in U. S. Patent No~
4,174,597 which issued November ~0, 1979 to ~ ~ li et al; U. S. Patent No.
4,138,932 which issued Februaly 13, 1979 to Mowli et al; U. S. Patent No. 4,126,085 which issued November 21, 19?8 to Mowli et al and U. S. Patent No. 4,117,934 which issued October 3, ]978 to Mowli et al, all of which emplo~ "twist tie~ elements with dead fold characteristics, i.e., once ~ent or folded the element remlins in its bent shape and d oe s not spr m g back or tend to return to its original shape.
Ihe above cbjects are achieved by the present invention which is better understood by reEerence to the following summQry of the invention, description of the drawings, and detailed description.

SUMM~RY OF THE INVENTION

In one aspect the present invention is a method of making an easy cpen package having an int2gral dead fold element comprising the steps of:
(a) prcvidLng a side seal bag constructed of flexible therm~plastic film material, said film having at least tw~ layers, said bay having an open end and a closed e~d;

(b) removing corner portions of said bag adjacen-t to said end opening so that two extended lip por-tions are :Eormed;
(c) a-ttaching a strip-like dead fold elemen-t to an inner surface of at leas-t one of said extended lip portions;
(d) folding said extended lip portions into said end opening so as to surround and encompass said dead fold element within the fold of the lip portion -to which the element is attached, said folds bringing portions of the outer surface of the bag into direct contact;
(e) flattening and heat sealing said folded li.p portions to enclose said dead fold element within its respective fold and to close said bag, said heat seal being -transverse across the width of the bag and being located bètween the fold line and the edge of inwardly folded lips, said folds providing grippable tabs for pulling said folds apart to open said bag, the rupture strength of -the outer layer being greater than -the bond strength between the outer layer and the layer adjacent thereto whereby when the -tabs are gripped and pulled apart the outer layer first ruptures then delaminates -to the end of the folded lip por-tion to open said bag; and, (f) filling said bag with a product prior to -the application of the heat seal in step (e) whereby an easy open package with a reclosable dead fold closure element is provided.
In another aspect, the present invention is a package having a reclosable feature comprising:
(a) a bag constructed from a multi-layer thermoplastic packaging film, said film having at leas-t two layers, said bag having a closed end and a mouth end;
(b) an inward fold of the lip of the mouth of said bag, said fold being along a line so that por-tions of the ou-ter surface of said bag are in direct contac-t;
,~

(c) a product wi-thin the bag;
(d) a transverse heat seal across -the width of the bag, said seal being located between the fold line and the edge of the folded under lip, said outer surface portions being sealed together by said seal said folds providing grlppable tabs which can be pulled apart to open said bag, -the rupture strength of the outer layer being greater than the bond strength between the outer layer and the layer adjacent thereto whereby when the tabs are gripped and pulled apart the outer layer first ruptures then delaminates to the end of the Lolded lip portion to open said bag; and, (e) a strip-like dead-fold element located within and enclosed by one of said folds along approximately one-half of said mouth whereby after said bag is opened it may be closed by bending said dead-fold element.
DESCRIPTION OF DRAWINGS
Attached here-to and made a part of this disclosure are the drawings showing principal features of the subject invention and in which:
Figure 1 is an exaggera-ted schematic representation of the seal area showing rupture of one outer layer and delamin-ation thereof from an adjacent layer;
Figure 2 is a cross-section in exaggerated detail of one embodiment of the package of the present invention;
Figure 3 is a top view of the embodiment shown in Figure 2;
Figure ~ is a top view of a flattened bag prior -to being provided with a dead-fold element and final seal; and, Figure 5 is a top view of a flattened bag ready to receive a product before final sealing.
PREFERRED EMBODIMENT
Referring first to Figure 2 a product 6 which may be cheese or luncheon meat is shown enclosed by mul-t.ilayer film F.
The receptacle made from multilayer film F can be formed in several different manners and may be -Sa-called a bag, pouch, package, etc. In ~he preferred embodiment a seamless tube of the three-layer film F is c:Losed at one end by end seal 13 which forms the bottom of bag or receptacle R. The receptacle is loaded with product 6 and, to close the loaded receptacle, an inward fold is made at its open end or mouth along line 12 wherein edges 9 and 10 are folded under so that they mate or coincide when the bag mouth is flattenecl. In the flattened condition a heat seal i8 applied by compressing the four layers of material in the seal area region A. All of the surfaces in contact in seal Region A will be sealed to each other. This configuration leaves separable tabs 4 and 5 which may be gripped by the fingers to pull tlle seal apart. When this occurs rupture and delamination shown in Figure 1 occurs.
In Figure 1 seal area A represents the seal which actually closes the opening to the receptacle or bag R. The seal is designated seal S in Figures 1 and 2. When tabs 4 and 5 are grasped between the fingers and pulled apart a delamination occurs at the beginning of the seal S in the area A as shown in Figure 1 and the delamination between layer 3 and its adjacent layer 2 continues to the edge E of the film so that opening 20 now provides access to the interior of the bag through the ruptured outer layer 3 of film F-1 of tab 4 and through the delamination between layer 3 and its adjacent layer 2 which continues to the edge of the film E. From this opening the product 6 may be removed and reinserted into the bag.
Referring to Figure 19 it is seen that the film F from which the bag is formed is a three-layer film having inner layer 1, middle or adjacent layer
2 and outer layer 3. (In Figure 2 it can be seen that outer layer 3 is on the outside of the bag.) A preferred three-layer film is that disclosed in U.S.
Patent No. 4,278,738 which issued on July 14, 1981 to Harri J. Brax et al.
Relating the Brax et al film to the layers to Figure 1, inner layer 1 is ~:192~

an ethylene-vinyl acetate copolymer which has been cross linked by irradiation and has a thickness of approximately l.5 mils; middle layer 2 is a copolymer of vinylidene chloride having a thickness of approximately 0.2 mils; and outer layer 3 is a crossl:inked ethylene vinyl acetate copolymer having a thickness ofapproximately 0.7 mils. The vinyl acetate content in the ethylene-vinyl acetatecopolymers is approximately 10% and the vinylidene chloride copolymer is a copolymer of vinylidene chloride and vinyl chloride in a mixture of 10% suspension polymerized and 90% emulsion polymerized copolymers. The emulsion polymerized copolymer consists of about 70% vinylidene chloride and 30% vinyl chloride and the suspension polymerized copolymer consists of about 80% vinyl:idene chloride and 20% vinyl chloride.
Using the film described above, which is available in a seamless tube so that an end seal 13 can be applied to close the bottom of the bag, the top of the bag when folded in a configuration shown in Figure 2 have the appearance shown in Figure 3 when laid flat. In this position, a heat seal can be applied across the width of the bag in area A. The width of the seal is one-eighth inch to one-quarter inch in width and can be applied by a sealing unit such as those made by the Vertrod Corporation of Brooklyn, New York or by any other heat seal unit as these are well known in the art.
A pressure of approximately twelve kilograms per centimeter is preferred and thesealing unit is set such that the temperature at the interfaces where sealing occurs is in the range of 225F to 300F. In a laboratory arrangement the totalsealing time consists of approximately 0.6 seconds for preheating the seal bars,0.3 seconds for the heated welding time as the pressure is applied to the area A, and approximately 0.1 seconds for release time. In a production operation the seal bars do not have time to cool and the preheat time will drop to approximately 0.1 second for a total sealing time of approximately 0.5 seconds.
A seal according to the foregoing will keep the package intact and ~9~ 7 will resist abuse yet the seal can be readily opened by grasping the tabs 4 and 5 of Figure 2 and pulling the~ apart whereupon one of the layers 3 as ln Figure 1 ruptures and delaminates to film edge E-1 or E-2. DelaminatLon i.s observed to occur rather than rerupture of the outer layer 3.
A reclosure feature is provided which can be a "twist-tie" strip or any piece of wire or other material which has dead-fold characteristics. Strip 7 is located within one of the end folds as shown in cross section in Figure 2 or in the top view in Figure 3. The dead-fold strip 7 can be inserted by simply punching a hold as indicated by the dotted lines 21 in Figure 2 and inserting the dead-fold strip into the hole. After the bag has been opened, it can be readily closed by rolling up the said bag material in the area 23 as one rolls up the used end of a tube of toothpaste and then crimping or bending the dead-fold strip to hold the roll of film material 23 secure.
Another method of providing a reclosure feature is shown in Figures 4 and 5. In Figure 4 a side seal bag or receptacle R is shown which has been formed by folding a sheet of film in its center and sealing it along its sides by heat seals 26. At the open end of the bag the corners are removed by cutting along dotted lines 27. When the corners are removed two opposed lips are formed which may readily be folded inside the bag. When the upper lip is folded in dead fold strip 7 having an adhesive surface is laid upon and secured to the upper surface of the lower lip afterwhich the lower lip is folded inwardly. The bag now has the configuration shown in Figure 5 with the edges F of the lips coinciding inside the bag, the lips having been folded along fold line 12. The bag is now ready to receive a product and when filled a transverse heat seal is applied in the area A
which closes and seals the bag with portions of the outer surface of the bag being sealed to itself in the area A. Film segments may be removed at 24 by punching or cutting. The removal of these segments tends to relieve the stress on the side seals when the fold tabs are pulled apart and direct the stress to seal area A to open the package.

Other materials which can be suitably used in the present invention are polyethylene and ethylene-vinyl acetate copolymers in general for the mater:ial for the outer layer and for the material of the adjacent layer materials can be selected from the group consisting of nylon, vinylidene chloride copolymers, propylene homopolymers and copolymers;
and, cross-li.nked polyethylene and ethylene-vinyl acetate copolymers.
The ch:ief criterion is that the tensile strength or rupture strength of the outer layer is greater than the bond strength between layers 2 and
3. Likewise, the bond strength between layers 2 and 3 has to be less than the rupture or tensile strength of adjacent layer 2 or of the combination of layers 1 and 2.
Other folding configurations are possible within the scope of the present invention as long as the fold results in outer layer 3 being sealed to itself in a face-to-face relationship so that when the rupture occurs there is delamination to a nearby or adjacent edge of the film resulting in an access opening to ehe interior of the package.
Having thus described my invention, I claim:

Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of making an easy open package having an integral dead fold element comprising the steps of:
(a) providing a side seal bag constructed of flexible thermoplastic film material, said film having at least two layers, said bag having an open end and a closed end;
(b) removing corner portions of said bag adjacent to said end opening so that two extended lip portions are formed;
(c) attaching a strip-like dead fold element to an inner surface of at least one of said extended lip portions;
(d) folding said extended lip portions into said end opening so as to surround and encompass said dead fold element within the fold of the lip portion to which the element is attached, said folds bringing portions of the outer surface of the bag into direct contact;
(e) flattening and heat sealing said folded lip portions to enclose said dead fold element within its respective fold and to close said bag, said heat seal being transverse across the width of the bag and being located between the fold line and the edge of inwardly folded lips, said folds providing grippable tabs for pulling said folds apart to open said bag, the rupture strength of the outer layer being greater than the bond strength between the outer layer and the layer adjacent thereto whereby when the tabs are gripped and pulled apart the outer layer first ruptures then delaminates to the end of the folded lip portion to open said bag; and, (f) filling said bag with a product prior to the application of the heat seal in step (e) whereby an easy open package with a reclosable dead fold closure element is provided.
2. The method of claim 1 including the step of punching out portions of the folds at the fold line adjacent the side seal to reduce stress on said side seals.
3. The method of claim 1 wherein the outer surface layer of said film is selected from the group consisting of poly-ethylene and ethylene vinyl acetate copolymers.
4. An easy open package having a reclosable feature com-prising:
(a) a bag constructed from a multi-layer thermo-plastic packaging film, said film having at least two layers, said bag having a closed end and a mouth end;
(b) an inward fold of the lip of the mouth of said bag, said fold being along a line so that portions of the outer surface of said bag are in direct contact;
(c) a product within the bag;
(d) a transverse heat seal across the width of the bag, said seal being located between the fold line and the edge of the folded under lip, said outer surface portions being sealed together by said seal said folds providing grippable tabs which can be pulled apart to open said bag, the rupture strength of the outer layer being greater than the bond strength between the outer layer and the layer adjacent thereto whereby when the tabs are gripped and pulled apart the outer layer first ruptures then delaminates to the end of the folded lip portion to open said bag; and, (e) a strip-like dead-fold element located within and enclosed by one of said folds along approximately one-half of said mouth whereby after said bag is opened it may be closed by bending said dead fold element.
5. The package of claim 4 wherein said bag is a side seal bag having corner portions removed from the mouth end of the bag.
CA000405609A 1981-08-21 1982-06-21 Easy open package having a reclosable feature Expired CA1192167A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US29515881A 1981-08-21 1981-08-21
US295,158 1981-08-21

Publications (1)

Publication Number Publication Date
CA1192167A true CA1192167A (en) 1985-08-20

Family

ID=23136480

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000405609A Expired CA1192167A (en) 1981-08-21 1982-06-21 Easy open package having a reclosable feature

Country Status (3)

Country Link
JP (1) JPS5841058A (en)
AU (1) AU8495582A (en)
CA (1) CA1192167A (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60103939A (en) * 1983-11-11 1985-06-08 水井 睦祥 Posture display apparatus
JP6891390B2 (en) * 2015-08-17 2021-06-18 凸版印刷株式会社 Packaging bag

Also Published As

Publication number Publication date
AU8495582A (en) 1983-02-24
JPS5841058A (en) 1983-03-10

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