Tearable sheet construction
US 3127087 A
Description (OCR text may contain errors)
March 31, 1964 A. T. sPEl-:s
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ARTHURT. SPEES March 31, 1964 A. T. sPEEs 3,127,087
TEARABLE SHEET CONSTRUCTION Filed Sept. '7, 1960 3 Sheets-Sheet 2 FIG.|8 FIG. IQ FIG. 2O
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March 31, 1964 Filed Sept. 7, 1960 ARTHuRTSPEr-:s
@Mq/M nited States Patent 3,127,037 TEARABLE SHEET CONSTRUCTION Arthur T. Specs, 2540 W. '7th St., Los Angeles 5, Calif. Filed Sept. 7, 1960, Ser. No. 54,471 Claims. (Cl. 229-51) This invention has to do generally with means for effectively tearing thermoplastic sheet material along a predetermined line without the aid of an implement or tool and with the construction of tearable sheets and packages.
The invention is generally similar in nature and use to that set forth in my copending application for patent, entitled Tear Strip Means for Plastic Packaging, Serial No. 613,850, filed October 4, 1956, and now Patent No. 2,991,000 and reference is made thereto for a discussion of the use of thermoplastic materials in packaging, and the desirability of having incorporated therein an effective means whereby a package or container of such material can be readily opened in a predetermined region by a simple tearing action. This application, however, is primarily a continuation-impart of my copending application, entitled Tear Tape, Serial No. 691,421, led October 2l, 1957, now Patent No. 2,952,395, and to a lesser extent, a continuation-in-part of said application, Serial No. 613,850.
An object of the invention is to provide a package or container embodying novel means for enabling a person to readily open the package alonga predetermined line or region.
A further object in this connection is to provide novel forms of container construction.
Another object is to provide novel tearable constructions in a sheet material comprised in part at least of thermoplastic material.
More particularly it is an object to provide a novel tearable construction for laminated sheet material comprised of a layer of relatively tough, stretchable material (which may or may not be a synthetic resin of the thermoplastic type) and a layer of a relatively non-stretchable material.
These and other objects will be apparent from the drawings and the description which follow. Referring to the drawings:
FIG. l is a front face view of a bag-type container embodying the invention;
FIG. 2 is an enlarged face View of the upper arrowencircled corner portion of the container of FIG. 1;
FIGS. 3, 4, 5 and 6 are sectional views on lines 3 3, 4 4, 5 5 and 6 6, respectively, of FIG. 2;
FIG. 4a is an enlarged fragmentary View of the central portion of the showing in FIG. 4;
FIG. 5a is an enlarged fragmentary view of the central portion of the showing in FIG. 5;
FIG. 7 is a face View, partly broken away, of the upper portion of the container of FIG. 1, showing the tear tape partially severed;
FIG. 8 is a greatly enlarged fragmentary sectional View on line 3 8 of FIG. 7;
FIG. 9 is a diagrammatic View illustrating one method of making the tear tape;
FIGS. 10, 1l and 12 are sectional views on lines 10-10, 11 11 and 12-12, respectively, of FIG. 9, the views being enlarged for clarity with respect to the thickness dimension of the tape;
FIG. 13 is a face View of the corner of a container similar to that shown in FIG. 1, but showing a moditication;
FIGS. 14 and 15 are views similar to FIG. 13, but showing two other modifications, respectively.
FIG. 16 is a View similar to FIG. 1 showing a container of bag-like form, formed of a single sheet of ther- 3,l27,087 Patented Mar. 3l., 1964 moplastic material and embodying another form of my tear tape;
FIG. 17 is a sectional view on line 17 17 of FIG. 16;
FIG. 18 is a sectional view on line 13 13 of FIG. 16, but on a larger scale;
FIG. 19 is a View similar to FIG. 18, but showing a different application of the tear strip;
FIG. 20 is an enlarged sectional view through the type of tear tape shown in FIG. 19, with the sheet material to which it is applied shown modified;
FIG. 21 is an enlarged face view of the upper left corner portion of FIG. 16;
FIG. 22 is a face View of a bag-type container embodying another form of the invention;
FIGS. 23 and 24 are sectional views on lines 23 23 and lines Ztl- 24, respectively, of FIG. 22, the thickness of the material being exaggerated;
FIG. 25 is a view similar to FIG. 22 but showing a modified construction;
FIGS. 26 and 27 are sectional view on lines 26 26 and 27 27 respectively, of FIG. 25, but on a larger scale;
FIG. 28 is a view similar to FIG. 22, but showing another form of the invention;
FIG. 29 is a sectional view on line 29 29 of FIG. 28;
FIG. 30 is a plan view of a pouch or bag-type container embodying a modification;
FIGS. 3l and 32 are sectional views on line 31-31 and 32-32, respectively, of FIG. 30, but on a larger scale and with the thickness of the material exaggerated;
FIG. 33 is a fragmentary sectional View through a single sheet of thermoplastic material to which tear strip means has been applied;
FIG. 34 is a view similar to FIG. 33 showing another application; and
FIG. 35 is a fragmentary face view of the upper corner portion of the container of FIG. 22 partially torn open, the torn portion being shown in perspective.
More particularly describing the invention, in FIG. 1 I show a container 11 of bag-like form comprising a front sheet 12 and a rear sheet 14. The sheets have been shown as consisting of two layers of material forming a laminated construction in which the inner layer is formed of a thermoplastic material, such as polyethylene, and the outer layer of a non-thermoplastic material. Numerals 12A and 14A designate the inner layer of sheets 12 and 14, respectively, while numerals 12B and 14B, the outer layers.
The container 11 is sealed around its margins in the region outwardly of the broken line 15 in FIG. l by the application of heat and pressure, whereby the two inner layers 12A and 14A of the two sheets 12 and 14 are united in such region, designated 16.
In FIG. l, I show the forward sheet 12 of the container provided with a somewhat V-shaped cut-out portion or recess 18. In a continuous process of manufacture, holes 18 may be punched in the sheet material and, subsequently, after the bags or containers have been formed with the tear tape incorporated, the material, which is then doubled, comprising the front and rear sheets 12 and 14, as it appears in FIG. 1, may be cut along the lines 20 providing half of the hole portion 1S (recess 18), in each of the front sheets of adjacent bags or containers.
In order to provide means for readily and effectively opening the forward sheet 12 of the container, I provide a laminated tear strip which is designated generally 24. This is united with the inner side of sheet 12 and extends to project into the area of the cut-out or recess 18, providing a pull-tab portion 25. The tear tape is formed of an inner core or layer of a exible, relatively strong, stretch-resistant, non-thermoplastic material, designated 27 and outer covering layers 28 and 2S' of a thermoplastic material which may be the same as the material of layer 12A of sheet 12, or may be another material compatible therewith.
In the form of the invention shown in FIGS. 1 to 12 presently being described, the core or inner layer 27 of the tape is shown divided into three sections, namely, an inner or central section 27a and marginal sections 2711. These are shown separated byslits or lines of parting 30 extending longitudinally of' the tape. The tape 24 is lapplied to the inner surface of the sheet 12 by the application of heat and pressure, whereby the tape is thereby actually united with the thermoplastic inner layer 12a of sheet 12; In the region of the recess 18, the marginal sealing area 16 follows the outline of the recess 18, providing a sealed area 16a, and when the bag or container is sealed or formed in this region the tear tape 24 is sealed to and united with both the inner and outer sheets 12 and 14 so that a hermetically sealed joint is achieved in the region where the tape passes through the container to the outside thereof. At its other end the tape is also sealed between the sheets 12 and 14 in the sealed area 16.
It should be noted that there is a fusion of the thermoplastic layers 12A and 14A of the package and layers 218 and 28 of the tear tape around and into intimate contact with the lateral edges of the core of the tear tape 27 in the regions 31 as best shown in FIG. 4A thereby effecting a fluid-tight seal where the tape passes from the interior to the exterior of the package.
In FIG. 2 the tab portion 25 of the tape is shown provided with a pair of inclined slits 32, which cut through the outer marginal portions of the tape substantially to the slits 30. Consequently, when the tab is grasped andpulled forwardly and to the right, as shown in FIG. 7, the tape readily begins to part or tear along the slits inwardly of the slits 32 and carries with it the overlying portion of the front sheet 12, providing a slot 34 in the front of the container. It `will be apparent that in the tearing operation the portions of sheet 12 bordering slot 34 are strongly reinforced against stretching and tearing by the two marginal portions 27B and 27B of the tear tape 24, which remain secured to the sheet 12'. Since the inner core or layer 27 is much stronger than the front sheet 12, the latter readily gives Way and is precisely torn as the tear tape is pulled. v
While it is not essential that I utilize a tear tape such L as` that designated 24 having the slits 30 andthe inner layer or core, and in lieu thereof may use a tape which is merely scored or in which the core is so woven or processed at the time of manufacture that it has a tendency to tear readily longitudinally as opposed to other directions, I prefer to use the. construction previously outlined and in FIGS. 9-12 I show a simple method of making such a tape. Referring to these figures, in FIG. 9 I show the tape 24 which may be assumed to be traveling during processing in the direction of the arrow shown thereon. The tape is originally formed of three layers, namely, the inner layer 27 of flexible, non-thermoplastic, substantially non-stretchable, relatively strong material, and the two outer layers of thermoplastic material, these being designated 2S and 28. The three layers are laminated by any conventional process by which this is done in the art. As the tape proceeds in the direction of the arrow it is slit into three longitudinally extending strips designated 40, 41 and 42, as by means of cutters 43. Subsequently, heated rollers 44, or other means is used to apply heat and pressure, thereby re-uniting the segments of the outer layers as best shown in FIG. 12 so that only the core or inner layer 27 is left divided into its three component strips 27A, 27B and 27B. After the outer layers of the tape have been re-united over the slits 30, fully enclosing and sealing the slitted areas, the resulting Vtape is applied to the Ysheetmaterial 12 by heat and pressure and across the center of opening 18. The tape is then cut, as by knives 45, to produce the slits 32 previously referred to. Following this, the rear sheet 14 is brought into place behind the front sheet 12 and the two united or sealed together in the aforementioned regions 16 and 16A, the rear surface or layer of the tape being sealed to sheet 14 in the region 16A and at the other end thereof.
If desired the tab end -25 of the tape may be releasably anchored to the rear sheet 14'of the container by heatsealing or by application of an adhesive in the region 48 (FIG. l2), thereby preventing the accidental dislodgment of the tab and possible premature opening of the container.
Referring now to FIG. 13, I show a modification wherein the tape, `designated 24A, is similar to the tape 24 previously described, except that the slits extending longitudinally of the core or inner layer of the tape here designated as 30A, terminate short of the end of the tape in the regions 52 where they intersect or substantially intersect slits 53 which extend through the entire body of the tape and serve to define a wide tab portion 54.
In FIG. 14, I show another modilication wherein the tear tape, here designated by numeral 24B, is shown provided with a tab portion 57 of reduced width and corresponding in width to and being a continuation of only the central section of the tape.
Referring now to FIG. 15, -I show the upper left-hand corner of a package or container designated 60, which is generally similar to that shown in FIG. l except that it is not provided with the recess 18 heretofore described. lIn this form of the invention the tear tape, which is designated by numeral 24C, extends to the edge 62 of the container and a pull-tab portion `63 is yformed by the provision of the interrupted slits 62 extending diagonally inward from the edge 62 in a converging direction to intersect or nearly intersect with the longitudinal slits 30 of the tear tape. Thus, both the front and rear sheets of the container, as well as a tab portion of the tear tape in the region defined by the slits 64, form a pull-tab for the tape. The interrupted slits 64 serve to hold the pull-tab segments in position until used in opening the package and guard against premature opening. When the tab is pulled the front sheet is cleanly sheared as previously described in connection with the `description of FIGS. 1-7; however, since in this case the tab is also formed in part by the rear sheet of the package, the rear sheet of the package necessarily tears approximately along line i65 as the tab is pulled.
In FIGS. 16 to 18 and in FIG. 21, I show another form of the invention which is designed particularly for use in connection with a sheet 70 of single-thickness thermoplastic material. The sheet 70 is shown shaped to form a container 71, which is folded at 72 and 73 upon itself and heat-welded or united along a seam 74. The lateral margins are shown sealed in the regions 75 by heat and pressure. In this instance, the tear tape, which is designated generally by numeral 78, is shown as comprising a laminated two-layer tape comprising one layer 79 of thermoplastic material which is united to the inner surface of the sheet 70, and another layer 80 which comprises 4the center-strip 80A, and two marginal strips 80B of non-thermoplastic, non-stretchable, relatively strong material. In this `form of the invention, the tape extends out to the edge 82 of the container and has a tab end 83 defined by slits 84 at the margin of the sheet. The tab end may be formed in any of the ways previously described. Since the sheet 70l is reinforced by sections 80B of the tape, the portion of the sheet overlying the center section of 4the tape is readily torn out when the tape is pulled.
yIn FIG. 19, I show a modification wherein the tear tape, designated 78A, is similar to the tape 78, but placed on the outside of the container. A portion (not shown) is left -free at one end of the tape to act as a tab and this may be formed as in FIG. 2, FIG. 13, or FIG. 14. In operation, when the central portion of the tape is pulled,
it serves to sever the sheet of the container along lines coincident with the slits 85 in the non-thermoplastic layer `86 of the tape. In this connection, should the material of the container be exceptionally thick or strong, it may be weakened in the region of the tape by causing a thinner section to occur at this region as the tape is applied by heat and pressure, as indicated at 90 in FIG. 20.
Referring now to FIGURES 22-24, I show a container 100 formed of two sheets, 101 and 102, each of which is a laminate and comprises an inner layer 103 of thermoplastic material, such as polyethylene, and an outer layer 104 of non-thermoplastic material. The sheets are joined a-t the areas 105 marginal to their edges by the application of heat and pressure, providing a completely sealed package.
In FIGS. 1712 to 24 I show a simplied construction of a tearable means incorporated in the sheets and this comprises a line of slits 107 in each of the outer nonthermoplastic layers of the sheets, the line of slits of sheet 101 registering with the line of slits in sheet 102. The method of `forming the slits or line of slits 107 in each sheet consists of slitting a sheet of the material completely through both layers 103` and 104 and subsequently closing the slits in the layer 103 by means of heat and pressure thereby to restore the sheet 103 substantially to its original condition. This is essentially the same as the method employed in connection with the making of the tear strips previously described. The line of slits 107 may be formed as a single long slit but here I prefer an intermittently slitted or perforated line. In its broader aspects the invention embodies weakening the non-thermoplastic layer by means other than as shown and described herein.
To open the package 100 it is only necessary to grasp the package above and below the line of slits 107 and tear it inwardly from one edge along the line 107 as shown in FIG. 35.
In FIGS. 25-27 I show a somewhat modiiied package construction wherein a package 110 is formed of two sheets which are the same as the previously described sheets 101 and 102, and, where the parts are the same as in the FIGS. 22-24, they are correspondingly numbered in FIGS. 25-27 except for the addition of the suix A. Across one sealed margin 105A of the sheets I provide a lightly or imperfectly joined area 111. In this form of the invention the line of slits in the outer layers of the sheets, here designated 107A, includes a section 112 which is in the region of the imperfectly joined area 111 and includes a diagonal section 114 which passes through an unsealed corner portion of the package and then through the sealed marginal area 105A. With this construction the package may be torn open initially along line 114 and then along line 112 through section 111. This opens the package at the corner, then, if desired, the package may be opened completely across the top merely by separathig the two sheets in the imperfectly sealed area 111 remaining inwardly of the line of slits 112.
In FIGS. 28 and 29 I show another application wherein a package 120 which is formed of sheets 101B and 102B are sealed in the region 105B. In this form of the invention the line of slits, here designated 107B is provided across and in the area of the sealed marginal area 105B except for a central section 121 wherein the line dips below or inwardly of the sealed marginal area 105B. When this package is opened, as by tearing off the portion above the line of slits, a central opening is provided in the packge. The versatility of the construction will be apparent from the FIGURES 22, 25 and 28 which are merely indicative of the numerous constructions which can be employed. It is to be understood that, although I have shown sheets of two layers only, the basic construction is applicable to laminated sheets comprised of several layers in which case the non-thermoplastic layers remain cut or perforated while the thermoplastic layers are closed or resealed.
In FIGS. 30-32 I show another application of the principles heretofore set forth. In these iigures numeral designates a pouch or bag-type package comprising one wall formed of a sheet 131 comprising an inner layer of thermoplastic material 132 and an outer layer of nonthermoplastic material 133 together with a second wall comprising a sheet 135 having inner and outer layers 136 and 137, respectively, of thermoplastic material and an intermediate layer 138 of non-thermoplastic material. The package is closed by a marginal heat-sealed region 140. In a central area designated 141 I provide a plurality of slits 142 which, for convenience, are shown as defining a plurality of rectangular areas 143. The slits in the intermediate layer can best be made by cutting the entire sheet material through all three layers and subsequently restoring the inner and outer layers by application of heat and pressure. I then provide a tear strip 145 consisting of an inner layer 146 of a thermoplastic material which is united by heat and pressure to the layer 137 directly over any one of the areas 143. The inner side of sheet 131 may be provided with a non-thermoplastic barrier 148 to facilitate application of the strip 145 and prevent unwanted sealing of the inner surfaces of the two opposed walls of the package should the strip be applied after the package is formed. When strip 145 is pulled sections of the inner and outer layers 136 and 137 and a section 143 of the intermediate layer are torn as a unit from the package. By providing a plurality of sections 143, it is an easy matter to apply the tear strip 145 without requiring care to insure registration.
When it is possible to exert a pulling force in opposite directions in the plane of a sheet, or where it is possible to tear a single sheet from the edge the constructions shown in FIGS. 33 and 34 are suitable. Referring iirst to FIG. 33, this construction consists of a tear strip 150 applied to a single-layer sheet 151 of thermoplastic material. The strip 150 is a laminate and may comprise an inner layer 152 of a thermoplastic material united with the sheet 151 and an outer layer of non-thermoplastic material 153. The latter is provided with a slit or series of slits 154 along which the sheet is torn.
In FIG. 34, the thermoplastic sheet to be torn is reinforced on opposite sides of a line or narrow region along which the tear is to be eiected in much the same manner as shown in FIG. 33. However, here a reinforcing strip 161 is applied on each side of the sheet, each strip having an inner layer 162 of thermoplastic material and an outer layer 163 of non-thermoplastic material. The strips are aligned so that their adjacent edges are substantially in the same plane along any given line thus reinforcing the sheet and enabling it to be torn along the region designated 164.
It will be apparent that the various constructions shown and described are based upon the principle of reinforcing the ordinarily stretchable thermoplastic layer or sheet on opposite sides of a line or area to be torn. In some cases it is convenient to do this by the addition of a tear tape such as shown in FIGS. l-21 and FIGS. 3l and 32, in others it is feasible to accomplish this by the addition of a reinforcing strip or strips as shown in FIGS. 33 and 34, while in othere it is feasible to accomplish this by weakening the already present relatively non-stretchable non-thermoplastic layer of a laminate sheet as shown in FIGS. 22-29. Throughout the speciiication and claims I make reference to the terms thermoplastic and nonthermoplastic. I intend this in a relative sense in that the non-thermoplastic sheet be one which is not fusible in the same temperature range as the thermoplastic sheet, but might well be fusible at a temperature substantially above the temperature at which the so-called thermoplastic sheet becomes fusible.
It should also be pointed out that while the invention has been shown and described with reference to thermoplastic sheet material, either singly or laminated with other layers, it will be apparent that the essence of the invention is applicable for providing a tearable region across a tough, normally difiicult-to-tear sheet of material which is not thermoplastic as where such a material, having once been severed or cut, is capable of being restored substantially to its original condition by means other than heat fusion, as, for example, by chemical means, such as by application of a suitable solvent.
The relative strength of the non-thermoplastic sheet along the tear line can be controlled by suitably proportioning the perforate and non-perforate sections. Also, if required, the strength of the thermoplastic sheet can be increased in the region along the tear line by addition of material thereto in the form of a bead or strip of thermoplastic material.
it may further be pointed out that a removable tear strip can be provided in one sheet of a package by providing two parallel tear lines, such as tear line MP7 in FIG. 22, and having these terminate at one edge of the package to provide a pull tab in much the same manner as shown in FIGS. 1 and 2. It will be apparent from this and the previous description that various changes and modifications can be made in the invention without departing from the scope thereof as set forth in the claims which follow.
l. A container formed of sheet material comprising a laminate of at least one thermoplastic layer and one non-thermoplastic layer, said container being formed to provide juxtaposed walls joined at one margin of the container, said juxtaposed walls each having a tearable line section from said one margin of the container inwardly thereof with the tearable line section of one wall in registration with the tearable line section of the other wall, each tearable line section comprising a weakened section of said non-thermoplastic layer.
2. In a tearable construction for a sheet lof stretchable plastic or the like, a pair of stretch-resistant reinforcement sheet element strips integrally united with said sheet on the surface thereof, said pair of elements being disposed to leave a narrow unreinforced region of said sheet therebetween whereby said sheet may be readily torn in the region of said unreinforced region by relative movement of said reinforcement elements away from each other.
3. The construction set forth in claim 2 wherein said reinforcement elements are disposed on opposite sides of said sheet and have their adjacent edges disposed substantially in a common plane.
4. In a tearable' construction for a sheet of stretchable thermoplastic material or the like, comprising a strip of laminate having at least one thermoplastic layer and one non-thermoplastic layer, said thermoplastic layer being united with said sheet, and said non-thermoplastic layer being substantially weakened along a given line.
5. A readily tearable construction in a normally difficult-to-tear flexible laminate sheet suitable for packaging andthe like, comprising at least one layer of a relatively stretchable, difficult-to-tear material and a layer of a relatively non-stretchable material bonded thereto, said sheet being characterized by a weakened line section across a portion at least of said layer of non-stretchable material.
6. The construction set forth in claim 5 in which the weakened line section across a portion of said layer of non-stretchable material is formed by perforations through said layer.
7. The construction set forth in claim 5 in which the layer of relatively stretchable, difiicult-to-tear material is a plastics of the thermoplastic type and in which the other layer is of a material which is not thermoplastic.
8. In a tearable construction for a laminate sheet having a first layer of stretchable material and a second layer of relatively nonstretchable material bonded thereto, the improvement comprising a weakened area formed in said second layer by a plurality of interruptions in the continuity of said sheet, and a tear strip united with said first layer in a region overlying the weakened area of the second layer.
9. The construction set forth in claim 8 in which the material of said first layer is a plastics of the thermoplastic type, and in which said tear strip has a surface of similar material united with said first layer overlying the weakened area of the second layer.
10. The construction set forth in claim S in which said laminate sheet has a third layer of a stretchable material and said second layer is sandwiched between said first and third layers.
References Cited in the file of this patent UNITED STATES PATENTS 2,226,181 Ridderstrom Dec. 24, 1940 2,476,564 Rosen July 19, 1949 2,554,160 Von Gunten May 22, 1951 2,866,589 Zacker Dec. 30, 1958 2,891,713 ONeil June 23, 1959