Claims
- 1. A pouch containing a flowable material, said pouch having transversely sealed ends, having a tear initiation locus adjacent at least one of the transversely sealed ends, said pouch being made with a transversely tearable film laminate, said film laminate comprising a machine direction oriented linear low density polyethylene film, a sealant film laminated onto at least one side of said oriented film, the sealant film having an Elmendorf tear in the machine direction of at least about 2 g/.mu.m, and the selection of said oriented film and said sealant film being made on the basis that:
- KX>(1-Y)
- Wherein
- K is a factor defined as (1-Y/Y.sub.r) and empirically determined so as to make the above expression true for laminates which will tear more easily and consistently in the transverse direction than in the machine direction and false for other laminates, said factor depending on the properties of the oriented film and the sealant film,
- X is the thickness of all layers of sealant film in micrometer,
- X.sub.e,uns/r/ is the thickness of all layers of sealant film in micrometers at which there is a change in the tearing property of the laminate from the machine direction to the transverse direction,
- Y=(MD.sub.c)/(TD.sub.c)
- MD.sub.c is the Elmendorf tear strength, in the machine direction, of the oriented film, measured in grams, and
- TD.sub.c is the Elmendorf tear strength, in the transverse direction, of the oriented film, measured in grams.
- 2. A pouch according to claim 1 wherein the oriented film is made from a polymer selected from the group consisting of at least one ethylene/C.sub.4 -C.sub.10 .alpha.-olefin copolymer having a density of from 0.900 to 0.940 g/cm.sup.3 and blends of such copolymer with a second polymer, selected from a homopolymer of ethylene and a copolymer of ethylene and vinyl acetate, said second polymer having a density of from 0.910 to 0.940 g/cm.sup.3, said blend having up to 70 wt. % of said second polymer.
- 3. A pouch according to claim 1 wherein the machine direction oriented linear low density polyethylene film is an ethylene/octene copolymer film.
- 4. A pouch according to claim 1 wherein the oriented film has a density of from 0.916 to 0.924 g/cm.sup.3.
- 5. A pouch according to claim 1 wherein the oriented film has been oriented in the machine direction at a draw ratio of from 1.5 to 6.5.
- 6. A pouch according to claim 1 wherein at least one of the films in the laminate is metallized or coated with a barrier coating.
- 7. A pouch according to claim 1 wherein the tear initiation locus is selected from a slit, a perforation, a nick, a thinning in the laminate and a tear tape applied to the laminate.
- 8. A pouch according to claim 1 wherein there is a heat-sealed area at or adjacent to one of the transverse seals at a corner of said pouch, said heat-sealed area joining the so-called front and back walls of said pouch and having a slit or perforation therein extending from the free edge of the heat sealed area.
- 9. A pouch according to claim 1 wherein there is a small compartment adjacent one of the transverse heat seals, and separated from the portion of the pouch containing the flowable material by a heat seal which joins the so-called front and back walls of said pouch, said compartment having therein a slit or perforation substantially parallel to said transverse heat seal.
Priority Claims (1)
Number |
Date |
Country |
Kind |
8828349 |
Dec 1988 |
GBX |
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Parent Case Info
This is a division of application Ser. No. 07/445,774, filed Dec. 4, 1989 now U.S. Pat. No. 5,091,241.
US Referenced Citations (10)
Foreign Referenced Citations (5)
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460963 |
Nov 1949 |
CAX |
764942 |
Aug 1967 |
CAX |
856137 |
Nov 1970 |
CAX |
893216 |
Feb 1972 |
CAX |
61-167550 |
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JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
445774 |
Dec 1989 |
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