CA1211083A - POUCHES MADE FROM BLENDS OF ETHYLENE-.alpha.-OLEFIN COPOLYMERS AND ETHYLENE-VINYL ACETATE COPOLYMERS - Google Patents
POUCHES MADE FROM BLENDS OF ETHYLENE-.alpha.-OLEFIN COPOLYMERS AND ETHYLENE-VINYL ACETATE COPOLYMERSInfo
- Publication number
- CA1211083A CA1211083A CA000429355A CA429355A CA1211083A CA 1211083 A CA1211083 A CA 1211083A CA 000429355 A CA000429355 A CA 000429355A CA 429355 A CA429355 A CA 429355A CA 1211083 A CA1211083 A CA 1211083A
- Authority
- CA
- Canada
- Prior art keywords
- ethylene
- film
- vinyl acetate
- copolymer
- alpha
- 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
Abstract
ABSTRACT OF THE DISCLOSURE
Pouches containing a flowable material e.g. milk, ice cream mix are disclosed. The sealant film from which the pouch is made, is of a blend of a linear ethylene-C4-C10 .alpha.-olefin copolymer and an ethylene-vinyl acetate copolymer.
The ethylene-C4-C10 .alpha.-olefin has a density of 0.916 to 0.930 g/cm3 and a melt index of from 0.3 to 2.0 dg/min. The ethyl-ene-vinyl acetate copolymer has a weight ratio of ethylene vinyl acetate from 2.2 to 24 and a melt index of from 0.2 to 10 dg/min. The blend has a ratio of linear ethylene-C4-C10 .alpha.-olefin copolymer to ethylene vinyl acetate copolymer of from 1.2:1 to 9:1.
Pouches containing a flowable material e.g. milk, ice cream mix are disclosed. The sealant film from which the pouch is made, is of a blend of a linear ethylene-C4-C10 .alpha.-olefin copolymer and an ethylene-vinyl acetate copolymer.
The ethylene-C4-C10 .alpha.-olefin has a density of 0.916 to 0.930 g/cm3 and a melt index of from 0.3 to 2.0 dg/min. The ethyl-ene-vinyl acetate copolymer has a weight ratio of ethylene vinyl acetate from 2.2 to 24 and a melt index of from 0.2 to 10 dg/min. The blend has a ratio of linear ethylene-C4-C10 .alpha.-olefin copolymer to ethylene vinyl acetate copolymer of from 1.2:1 to 9:1.
Description
POUCHES OF ETHYLENE-~-OLEFIN COPOLYMER/
ETHYLENE-VINYL ACETATE COPOLYMER BLENDS
The invention relates to pouches filled with flow-able materials, e.g. liquids, particularly to pouches made on so-called vertical form and fill machines.
It is well known to package plowable materials, for example, milk, on a so-called vertical form and fill machine.
Using such a machine, a flat wok of synthetic -thermoplastic film is unwound from a roll and formed into a continuous tube, in a tube-forming section by sealing the longitudinal edges of the film together to form a so-called lap seal or a so-called fin seal. The tube thus formed is pulled vertical-lye downwards to a filling station. The tube is then collapse Ed across a transverse cross-section of the tube the post-lion of such cross-section being at a sealing device below the filling station. A transverse heat seal is made, by the sealing device, at the collapsed portion of the tube, thus making an air-tight seal across the tube. The sealing device generally comprises a pair of jaws, and is described more fully hereinbelow. After making the transverse seal, but before the jaws of the sealing device are opened, a priest quantity of material to be packaged e.g. liquid is allowed to enter the tube, at the filling station, and fill the tube upwardly from the aforementioned transverse seal. The tube is then allowed to drop a predetermined distance under the influence of the weight of the material in the tube. The jaws of the sealing device are closed again, thus collapsing the tube at a second transverse section, which is above, usually just above, the air/material interface in the tube.
The sealing device seals and severs the tune transversely at the second transverse section. The material-filled portion of -the tube is now in the form of a pillow shaped pouch.
Thus the sealing device has sealed the top of a filled pouch, sealed the bottom of the next-to-be-formed pouch and US separated the filled pouch from the next-to-be-Eormed pouch, all in one operation.
',~;, One vertical form and fill machine o-f the type described above is a Proposes liquid packaging machine.
A sealing device commonly used is a so-called impulse sealer which has a sealing element mounted in sealing jaws and electrically insulated ~herefromO In operation the sealing jaws are closed and an electrical current is caused to flow through a sealing element e.g. a wire, for a fraction of the time that the jaws are closed. The jaws remain closed during a cooling period in which the seals partially solidify lo before the sealing jaws are opened. The transverse seal thus obtained support the weight of the plowable material e.g.
liquid, in the next-to-be-formed pouch.
A sealing element made of round wire e.g. "piano"
wire about lo to 2.5 mm diameter, electrically insulated lo from a water cooled supporting jaw, may be used but a wire of rectangular cross-section is preferred. These types of seal-in elements may be used for making both -the longitudinal and transverse seals.
The temperature of the sealing element during passage of the electrical current is largely determined by the resistance of the sealing element, the voltage applied across the element, the heat -transfer rate through the film being sealed and the temperature and mass of the jaw of the sealing device. A may be seen, operation of the impulse sealer may affect the seal strength and it is desirable to optimize such operation.
When a liquid is packaged in pouches as described above, the liquid, especially ire aqueous, aids in cooling the transverse seal in the tube after the sealing jaws are open-Ed because of the liquid's relatively high thermal conduct tivity. It appears that the cooling effect of the liquid on the seal takes effect before the weight of the liquid can weaken or rupture the bottom seal.
USE Patent 3 682 767 issued 1979 August 8 to Briton et at, discloses liquid filled pouches made from films of blends of a) 90-50 White of a random copolymer o-f *denotes trade mark.
. .
ethylene and an oleflnic unsaturated monomer e.g. vinyl acetate, which is present in -the amount of 2-10 White of toe copolymer and b) 10-50% ox a linear copolymer of ethylene and a C3-C20 ~olefin of a density of about 0.930 to 0.960 g/cm3.
It is more common, commercially, to use film made from a lend containing 70-90% linear ethylene-butene Capella-men having a density of about OWE g/cm3 and a melt index offbeat 0.75 dg/min and 10-30% high pressure polyethylene i.e.
a homopolymer, having a melt index of about 2 to 10 and a density of from 0.916 to 0 7 924 g/cm3. Density is determined by ASTM Procedure D1505-68 and melt index by ASTM Procedure D1238-79 (Condition Eye Such films having a thickness of about 76 micrometers, have been used for making pouches con-twining about 1.3 liters of milk. Pouches made from such film are generally satisfactory from the standpoint of pouch toughness and puncture resistance, but suffer from a tendency to have weak transverse end and/or longitudinal weals even though the operating conditions of the impulse sealer have been optimized. Defective seals may lead to the phenomenon known as leakers in which the plowable material e.g. milk, may escape from the pouch through pinholes which develop at or close to the seal. It has been estimated that leakers account for about 1-2% of the 1.3 lithe milk pouch production.
It has been proposed that increasing the film thickness would overcome the problem of leakers. however, it has been shown that even at film thicknesses of up to about 127 micrometers the percentage of leakers is not substantial-I lye reduced and yet the cost of the unfilled pouch is increase Ed in proportion to the increase in thickness of the film It has been suggested that melt strength, hot tack strength and heat-seal strength would be good measures on which to select films to produce pouches having improved seal integrity and therefore reduce the number of leavers. On these bases, however, it appears that one skilled in the art would not have any reason to believe that other polyolefins or blends of polyolefins perform any better -than the adore-mentioned lend owe linear ethylene-butene copolymer and high pressure polyethylene Surprisingly, however, it has now been found that pouches made from certain film of linear copolymers of ethylene and a C~-Clo ~-olefin, admixed wit ethylene-vinyl acetate copolyrners (EVA resins) jive s~lbstan~
tidally better performance with respect to the problem ox leakers. Indeed, because of this improved performance it is possible to make pouches of film with thinner film than was heretofore possible with the aforementioned film of the blend of ethylene-butene copolymer and high pressure polyethylene.
Accordingly the present invention provides a pouch containing a plowable material, said pouch being made from a sealant lo in tubular form and having transversely heat-sealed ends, said film being made from a blend of a linear ethylene-C4-Clo ~-olefin copolymer and an ethylene vinyl acetate copolymer, said ethylene-C4-Clo ~-olefin copolymer having a density of prom 0.916 to 0.930 g/cm3 and a melt index ox from 0.3 to 2.0 dg/min, said ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate Eros 2.2:1 to 24:1 and a melt index of from 0.2 to 10 dg/min, said blend having a weight ratio of linear ethylene-C4-Clo ~olefin copolymer to ethylene vinyl acetate copolymer of prom 1.2:1 to 9:1.
A preferred blend has a weight ratio of linear ethylene-C4-Clo ~-olefin copolymer to ethylene-vinyl acetate copol~mer of 2.33:1 to 9:1.
In a ureter embodiment the blend ox linear ethyl-ene-C4-Clo ~-olefin copolymer and ethylene vinyl acetate copolymer has admixed therewith from 13 to 18 parts of a high pressure polyethylene having a density in the range ox 0.916 to 0.924 g/cm3 and a melt index in the range of 2 to 10 dg/min per 100 parts of said lends of copolymer.
In another embodiment the ekhylene-C~-Clo a-olefin copolymer is selected from ethylene-butene or ethylene-octene copolymers, especially ethylene-octene copolymer~
In a further embodiment the film has a thickness from 38 to ]27 em, preferably from 51 em to 102 em.
In another embodiment the pouch contains from about 1~25 to 2 liters of a liquid or emulsion and the film thick-news is Eros about 51 to 127 em.
As used herein the term "plowable material" does not include gaseous materials, but encompasses materials which are flcwable under gravity or may be pumped. Such materials include liquids e.g. milk, water, fruit juice, oil, emulsions e.g. ice cream mix, soft margarine; pastes e.g.
meat pastes, peanut butter; preserves e.g. jams, pie fillings marmalade; jellies, doughs; ground meat e.g. sausage meat;
powders e.g. gelatin powders, detergents; granular solids e.g. nuts, sugar; and like materials. The invention is particularly useful for plowable foods e.g. milk.
In a specific embodiment the pouch contains from about 0.1 to 5 liters, particularly from 1 to 2 liters, of a wobbly material. Preferably the plowable material is a liquid, especially milk, water, fruit juice, or an emulsion, e.g. ice cream mix, soft margarine.
The present invention also provides a pouch con-twining a plowable material, said pouch being made from a film in tubular form and having transversely heat-sealed ends, said film comprising being a laminate of a base film and a sealant film, said base film being selected Eros the group consisting of nylon film, polyethylene terephkhalate film, polyvinylidene chloride film, polyvinyl chloride film, polyacrylonitrile film, polystyrene film and saponified ethylene-vinyl acetate film and said sealant film being made from a blend of a linear ethylene-C4-C10 a -oleEin copolymer and a ethylene-vinyl acetate copolymer said ethylene-C4-Clo ~-oleEin copolymer having a density of from 0.916 to 0.930 g/cm3 and a melt index of from 0.3 to I dg/min, said ethylene-vinyl acetate copolymer having a weight ratio of ethylene -to vinyl acetate of from 2.2:1 to 24:1 and a melt index of from 0.2 to 10 dg/min, said blend having a weight ratio of linear ethylene C~Clo ~-olefin coplanar to ethylene-vinyl acetate copolymer of from 1.2:1 to 9:1, said sealant film briny on the inside of the pouch.
In a preferred embodiment the weight ratio of ethylene-C~-C10 a -olefin copolymer to ethylene vinyl acetate copolymer is from 2.33:1 to 9:1.
In another embodiment the blend of ethylene-C4-Clo ~-olefin copolymer and ethylene-vinyl acetate copolymer has admixed -therewith from 13 to 18 parts of a high pressure polyethylene per 100 parts of said blend, said high pressure polyethylene having a melt index in -the range of 2 to 10 dg~min and a density of from 0.916 to O.g24 g/cm3.
In a further embodiment -the base film is selected from nylon 66, nylon 6, nylon 66~6 copolymer, nylon 6/10 copolymer, nylon 6/11 copolymer and nylon 6/12 copolymer.
Preferably the base film is nylon 66~ nylon 6 or nylon 66/6 copolymer.
In yet another embodiment, the base film and the sealant film have a layer of polyvinyldiene chloride (PVDC~
interposed there between In another embodiment the laminate comprises a base film sandwiched between two sealant films.
In a further embodiment -the plowable material is an oil, especially vegetable oil or motor oil and the base film it a nylon film.
The present invention also provides, in a process for making pouches filled with a plowable material on a vertical form and fill machine, in which process each pouch is made from a flat web of film by forming a tubular film therefrom with a longitudinal seal and subsequently flatten-in the tubular film at a eeriest position and transversely heat sealing sail tubular film at the flattened position, filling the tubular iamb with a predetermined quantity of plowable material above said first position, flattening the -tubular film above the predetermined quantity of plowable material at a second position and transversely heat sealing said tubular film at the second position, the improvement comprising making the pouches from a flat web of film made from 60 to 90 parts ethylene-C~-Clo -olefin copolymer having a density from 0.916 to 0.930 g/cm3 and a melt index from 0.3 to 2.0 dg/min admixed with 10 to 40 parts ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate of prom 2.2 to 24 and a molt index of from 0.2 to 10 dg/min.
In a preferred embodiment the film web used in the process is made from the blend of the linear ethylene-C4-Clo ~-olefin copolymer and ethylene-vinyl acetate copolymer, blend has admixed therewith from 13 to 18 parts of a high pressure polyethylene having a density in the range of 0.916 to 0.924 g/cm3 and a melt index in the range of 2 to 10 dg/min per 100 parts of said blend.
In another embodiment the ethylene-C4-Clo -olefin is selected from ethylene-butene or ethylene-octene Capella-men, especially ethylene-octene copolymer.
The linear ethylene-C4-Cloa -olefin copolymer use-fur in the present invention may be made from ethylene and an ~-olefin by a process disclosed in Canadian patent 856 137 which issued 1970 November 7 to WOE. Baker, IoC~B~ Saunders and JAM. Stewart. The linear ethylene~C4-Cl~ a-olefin copolymer may also be made by other processes known to those skilled in the art.
The ethylene-C4-Clo ~-olefin copolymer, ethylene-vinyl acetate copolymer and high pressure polyethylene are often available in pellet form.
Blends of the pelleted polymers may be fed into a film exterior and extruded into film form. A preferred film manufacturing method is the so-called blown film process disk closed in Canadian patent 460 963 issued 1949 November 8 to I Fuller. Films may also be made using an internal or external cooling mandrel with the blown film process, as disk closed for example in Canadian patent 893 216 issued 1972 February 15 to M. Boeing and TV Thomas. The internal cool-in mandrel brown film process is preferred. The copolymers, and high pressure polyethylene if present, may be blended prior to feeding to the film extrude hopper, or may be blended at the time of extrusion just prior to melting in the extrude, or alternatively may be melt blended in the extrude.
It will be understood by those swilled in the art that additives e.g. US stabilizers may be added to the ethylene polymers from which pouches of the present invention are made.
The film, after manufacture, is slit longitudinally into appropriate widths. The width determines the diameter of the tube formed on the vertical form and fill machine.
Preferably, film having a thickness of 51 to 127 em in thickness, especially 63 to 76 em in thickness, is used for the pouches of the present invention.
Pouches containing plowable materials may then be formed in the general manner described hereinbeEore on a vertical form and fill machine e.g. Prepay IS-2 or IS-6 liquid packaging machine, using the ethylene-C~-Clo Olin copolymar/ethylene-vinyl acetate copolymer film described herein.
When the film is a single layer or comprises a base film sandwiched between two sealant films, the pouch may have a fin seal or a lap seal. When the film comprises a base film and a sealant film, the pouch has a fin seal, and the sealant film is on the inside of the pouch.
g When the pouch is made from a laminate as described herein before, the transverse sealing device may more advent-ageously comprise two sealing elements and a severing element as described in US patent 1 377 149 granted 1975 April 9 to RYE. Petersen. With such a sealing device two transverse seals are made across the tubular film above and below the transverse sections described hereinhefore and the tubular film is severed between the two transverse seals.
Film laminates as described herein, having nylon, particularly nylon 66, nylon 6 or nylon 66/6 copolymer base film are particularly desirable for packaging oleagenous liquids e.g. cooking oil, motor oil. The nylon film may be cast or oriented.
As indicated herein before examination of melt strength, hot tax strength and heat seal strength data for the linear ethylene-C4-Clo ~-olefin copolymer/ethylene-vinyl acetate copolymer blends used in the present invention leads one skilled in the art to believe that there would be no improvement in the number of leakers with pouches from such blends compared to that experienced with pouches made from a blend of linear ethylene-butene copolymer and high pressure polyethylene. In order to illustrate the lack of correlation between melt strength, hot tack strength and heat seal strength with pouch performance, several samples of films, were taken and melt strength, hot tack strength and heat seal strength were measure. 2 lithe pouches of water were made using such films and the number of leakers determined by means of a drop test. In the drop test the pouches were dropped end-wise 152.4 cm onto a concrete floor.
Melt strength, is the weight of extradite which will remain suspended for a period of 3 minutes from -the orifice of a standard melt index tester (ASTM Procedure D1238-79). Heat seal strength is determined using a peel strength test similar to that used in ASTM Procedure D903 on a sample of film sealed using a Sentinel* heat seal apparatus *denotes trade mark.
Hot tack strength may be determined ho ASTM Procedure ~3706.
TABLE I
Heat Seal Hot Tack smelt Strength Strength %
Strength 12.7mm 25.4mm Seal Film* (g/3mln) 180C 190CFailures A 0.31 2080 300 11.6 B 0.63 2040 300 2.3 C 0.38 2300 300 1.7 D 0.29 1950 800 10.3 E 0.49 1397 500 0.4 Film A is 76 em in thickness and is made from a blend of 85 parts of a linear ethylene-~-butene copolymer having a density of 0.919 g/cm3 and a melt index of 0.75 dg/min and 15 parts of a high pressure polyethylene having a density of 0.918 g/cm3 and a melt index of 8.5 dg/min.
Film B is 76 em in thickness and is made from a blend of 85 parts of the blend of Film A and 15 parts of an ethylene-vinyl acetate coplanar having a melt index of 0.35 dg/min and a vinyl acetate content of 12 wit%.
Film C is 76 em in thickness and is made from a blend of 85 parts of the blend of Film A and 15 parts of an ethylene-vinyl acetate copolymer having a melt index of 0.7 dg/min and a vinyl acetate content of 18 wit%.
Film D is 51 em in thickness and is made from an ethylene-~-octene copolymer having a density of 0.918 g/cm3 and a malt index of 0c84 dg/min~
Film E is 51 em in thickness and is made from the ethylene-~-octene copolymer of Film D and 20 wit% of the ethylene-vinyl acetate of Film B.
Pouches made from Films B, C and F are within the scope of the present invention.
From the values of melt strength, ho-t tack strung and heat seal strength data it would be expected that the ethylene-~-olefin copolymer/ethylene-vinyl acetate copolymer and, optionally, high pressure polyethylene blend film would show little, if any, advantage over the ethylene-butene copolymer/high pressure polyethylene blend film.
The following examples further serve to illustrate the invention.
Example l The following resins and/or resin blends were evaluated for their performance as liquid packaging films:
U. 85 parts of an ethylene-butene coupler having a density of 0.919 g/cm3 and a melt index of 0.75 dg/min blended with lo parts of a high pressure polyethylene having a density of 0.918 g/cm3 and a melt index of 8.5 dg/min;
V. 85 parts of the resin blend in U in turn blend-Ed with 15 parts of an ethylene-vinyl acetate copolymer having a melt index of 0.35 dg/min and a vinyl acetate content of 12 wit%;
W. 85 parts of the resin blend in U in turn blend-Ed with 15 parts of an ethylene-vinyl acetate copolymer having a melt index of 0.7 dg/min and a vinyl acetate content of 18 White.
Pouches made from blend U is not within -the scope of the present invention and exemplifies the prior art.
The resins or resin blends were extruded at a melt temperature of 232C into films of various gauges at 409 kg/hr using a extrude equipped with a 81.3 cm diameter circular die and an internal film cooling mandrel.
The films were processed into 2 lithe pouches, substantially filled with water, using a Prepay IS-6 liquid packaging machine. The pouches were subsequently tested for seal integrity by dropping them from a height of 152.4 cm and determining the percentage seal failures.
% Seal Failures Film Gauge: 51 em 76 em 102 em Blend V 100 11.6 11.3 V 0.9 2.3 2.7 W 1.0 1.7 0.3 Example 2 Resin composition U of Example I above was blended with a number of ethylene-vinyl acetate copolymers (ETA
resins) outlined below and extruded into films 76 us in thickness. The resin blonds were extruded at a melt tempera-lure of 221C, at a rate of 38~6 kg/hr trough a 22.9 cm diameter circular die The films were processed into 1.3 lithe pouches, substantially filled with water, using a Prepay IS-6 liquid packaging machine. The pouches were sub-sequently tested or seal integrity by dropping them from a height of 152.4 cm. and determining the percentage seal failures.
Wit %
EVA resin Vinyl Acetate Melt Index in the EVA % Seal Sample _(dg/min) Resin Failures U~15% EVA I 0.3 12.0 2 U-~15% EYE II 1~2 7.5 40 U+30% EVA II 1.2 7. 5 23 u+a,5~ EVA II 1.2 7.5 5 lo U+30% EVA III 0.8 9.5 38 U~15% EVA IV 3.0 28.0 0 U~15~ EVA V 0.7 18.0 0 U+30% EVA VI 7.0 9.0 7 U-~45% EYE VI 7 . 0 9 . 0 3 U+15% EVA VII 8.0 18.0 5 Example 3 The following resins and/or resin blends were evaluated for their performance as liquid packaging films:
U, 85 parts of an ethylene-butene copolymer having a density of 0. 919 gm/cm3 and a melt index of 0.75 dg/min blended with 15 parts of a high pressure polyethylene having a density of 0. 918 gmfcm3 and a melt index of I 5 dg/min, Y. 85 parts of an ethylene-octene copolymer having a density of 0.918 g/cm3 and a melt index of 0 . 84 dg/min blended with 15 pats of an ethylene-vinyl acetate copolymer having a melt index owe 3 dg/min and containing 2 8 wit% vinyl acetate, Z. 70 parts of an ethylene-octene copolymer having a density of 0.918 g/cm and a melt index of 0.84 dg/min blended with 30 parts of an ethylene-vinyl acetate copolymer having a melt index of I 2 dg/min and containing 7.5 wit%
vinyl acetate.
Pouches made from Blend U it not within the scope of the present invention and exemplifies the prior art.
The resins were extruded at a melt -temperature of 221C at a rate of 38.6 kg/hr. through a 22.9 cm diameter circular die, and the resulting blown film was cooled by an internal cooling mandrel. The films were subsequently processed into 1.3 lithe pouches containing 103 liters of water, using a Prepay IS-6 liquid packaging machine. The pouches were subsequently tested for seal integrity by dropping them from a height of 152.4 cm. and determining the percentage failures.
Blend% Seal Failures Y O
Z O
ETHYLENE-VINYL ACETATE COPOLYMER BLENDS
The invention relates to pouches filled with flow-able materials, e.g. liquids, particularly to pouches made on so-called vertical form and fill machines.
It is well known to package plowable materials, for example, milk, on a so-called vertical form and fill machine.
Using such a machine, a flat wok of synthetic -thermoplastic film is unwound from a roll and formed into a continuous tube, in a tube-forming section by sealing the longitudinal edges of the film together to form a so-called lap seal or a so-called fin seal. The tube thus formed is pulled vertical-lye downwards to a filling station. The tube is then collapse Ed across a transverse cross-section of the tube the post-lion of such cross-section being at a sealing device below the filling station. A transverse heat seal is made, by the sealing device, at the collapsed portion of the tube, thus making an air-tight seal across the tube. The sealing device generally comprises a pair of jaws, and is described more fully hereinbelow. After making the transverse seal, but before the jaws of the sealing device are opened, a priest quantity of material to be packaged e.g. liquid is allowed to enter the tube, at the filling station, and fill the tube upwardly from the aforementioned transverse seal. The tube is then allowed to drop a predetermined distance under the influence of the weight of the material in the tube. The jaws of the sealing device are closed again, thus collapsing the tube at a second transverse section, which is above, usually just above, the air/material interface in the tube.
The sealing device seals and severs the tune transversely at the second transverse section. The material-filled portion of -the tube is now in the form of a pillow shaped pouch.
Thus the sealing device has sealed the top of a filled pouch, sealed the bottom of the next-to-be-formed pouch and US separated the filled pouch from the next-to-be-Eormed pouch, all in one operation.
',~;, One vertical form and fill machine o-f the type described above is a Proposes liquid packaging machine.
A sealing device commonly used is a so-called impulse sealer which has a sealing element mounted in sealing jaws and electrically insulated ~herefromO In operation the sealing jaws are closed and an electrical current is caused to flow through a sealing element e.g. a wire, for a fraction of the time that the jaws are closed. The jaws remain closed during a cooling period in which the seals partially solidify lo before the sealing jaws are opened. The transverse seal thus obtained support the weight of the plowable material e.g.
liquid, in the next-to-be-formed pouch.
A sealing element made of round wire e.g. "piano"
wire about lo to 2.5 mm diameter, electrically insulated lo from a water cooled supporting jaw, may be used but a wire of rectangular cross-section is preferred. These types of seal-in elements may be used for making both -the longitudinal and transverse seals.
The temperature of the sealing element during passage of the electrical current is largely determined by the resistance of the sealing element, the voltage applied across the element, the heat -transfer rate through the film being sealed and the temperature and mass of the jaw of the sealing device. A may be seen, operation of the impulse sealer may affect the seal strength and it is desirable to optimize such operation.
When a liquid is packaged in pouches as described above, the liquid, especially ire aqueous, aids in cooling the transverse seal in the tube after the sealing jaws are open-Ed because of the liquid's relatively high thermal conduct tivity. It appears that the cooling effect of the liquid on the seal takes effect before the weight of the liquid can weaken or rupture the bottom seal.
USE Patent 3 682 767 issued 1979 August 8 to Briton et at, discloses liquid filled pouches made from films of blends of a) 90-50 White of a random copolymer o-f *denotes trade mark.
. .
ethylene and an oleflnic unsaturated monomer e.g. vinyl acetate, which is present in -the amount of 2-10 White of toe copolymer and b) 10-50% ox a linear copolymer of ethylene and a C3-C20 ~olefin of a density of about 0.930 to 0.960 g/cm3.
It is more common, commercially, to use film made from a lend containing 70-90% linear ethylene-butene Capella-men having a density of about OWE g/cm3 and a melt index offbeat 0.75 dg/min and 10-30% high pressure polyethylene i.e.
a homopolymer, having a melt index of about 2 to 10 and a density of from 0.916 to 0 7 924 g/cm3. Density is determined by ASTM Procedure D1505-68 and melt index by ASTM Procedure D1238-79 (Condition Eye Such films having a thickness of about 76 micrometers, have been used for making pouches con-twining about 1.3 liters of milk. Pouches made from such film are generally satisfactory from the standpoint of pouch toughness and puncture resistance, but suffer from a tendency to have weak transverse end and/or longitudinal weals even though the operating conditions of the impulse sealer have been optimized. Defective seals may lead to the phenomenon known as leakers in which the plowable material e.g. milk, may escape from the pouch through pinholes which develop at or close to the seal. It has been estimated that leakers account for about 1-2% of the 1.3 lithe milk pouch production.
It has been proposed that increasing the film thickness would overcome the problem of leakers. however, it has been shown that even at film thicknesses of up to about 127 micrometers the percentage of leakers is not substantial-I lye reduced and yet the cost of the unfilled pouch is increase Ed in proportion to the increase in thickness of the film It has been suggested that melt strength, hot tack strength and heat-seal strength would be good measures on which to select films to produce pouches having improved seal integrity and therefore reduce the number of leavers. On these bases, however, it appears that one skilled in the art would not have any reason to believe that other polyolefins or blends of polyolefins perform any better -than the adore-mentioned lend owe linear ethylene-butene copolymer and high pressure polyethylene Surprisingly, however, it has now been found that pouches made from certain film of linear copolymers of ethylene and a C~-Clo ~-olefin, admixed wit ethylene-vinyl acetate copolyrners (EVA resins) jive s~lbstan~
tidally better performance with respect to the problem ox leakers. Indeed, because of this improved performance it is possible to make pouches of film with thinner film than was heretofore possible with the aforementioned film of the blend of ethylene-butene copolymer and high pressure polyethylene.
Accordingly the present invention provides a pouch containing a plowable material, said pouch being made from a sealant lo in tubular form and having transversely heat-sealed ends, said film being made from a blend of a linear ethylene-C4-Clo ~-olefin copolymer and an ethylene vinyl acetate copolymer, said ethylene-C4-Clo ~-olefin copolymer having a density of prom 0.916 to 0.930 g/cm3 and a melt index ox from 0.3 to 2.0 dg/min, said ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate Eros 2.2:1 to 24:1 and a melt index of from 0.2 to 10 dg/min, said blend having a weight ratio of linear ethylene-C4-Clo ~olefin copolymer to ethylene vinyl acetate copolymer of prom 1.2:1 to 9:1.
A preferred blend has a weight ratio of linear ethylene-C4-Clo ~-olefin copolymer to ethylene-vinyl acetate copol~mer of 2.33:1 to 9:1.
In a ureter embodiment the blend ox linear ethyl-ene-C4-Clo ~-olefin copolymer and ethylene vinyl acetate copolymer has admixed therewith from 13 to 18 parts of a high pressure polyethylene having a density in the range ox 0.916 to 0.924 g/cm3 and a melt index in the range of 2 to 10 dg/min per 100 parts of said lends of copolymer.
In another embodiment the ekhylene-C~-Clo a-olefin copolymer is selected from ethylene-butene or ethylene-octene copolymers, especially ethylene-octene copolymer~
In a further embodiment the film has a thickness from 38 to ]27 em, preferably from 51 em to 102 em.
In another embodiment the pouch contains from about 1~25 to 2 liters of a liquid or emulsion and the film thick-news is Eros about 51 to 127 em.
As used herein the term "plowable material" does not include gaseous materials, but encompasses materials which are flcwable under gravity or may be pumped. Such materials include liquids e.g. milk, water, fruit juice, oil, emulsions e.g. ice cream mix, soft margarine; pastes e.g.
meat pastes, peanut butter; preserves e.g. jams, pie fillings marmalade; jellies, doughs; ground meat e.g. sausage meat;
powders e.g. gelatin powders, detergents; granular solids e.g. nuts, sugar; and like materials. The invention is particularly useful for plowable foods e.g. milk.
In a specific embodiment the pouch contains from about 0.1 to 5 liters, particularly from 1 to 2 liters, of a wobbly material. Preferably the plowable material is a liquid, especially milk, water, fruit juice, or an emulsion, e.g. ice cream mix, soft margarine.
The present invention also provides a pouch con-twining a plowable material, said pouch being made from a film in tubular form and having transversely heat-sealed ends, said film comprising being a laminate of a base film and a sealant film, said base film being selected Eros the group consisting of nylon film, polyethylene terephkhalate film, polyvinylidene chloride film, polyvinyl chloride film, polyacrylonitrile film, polystyrene film and saponified ethylene-vinyl acetate film and said sealant film being made from a blend of a linear ethylene-C4-C10 a -oleEin copolymer and a ethylene-vinyl acetate copolymer said ethylene-C4-Clo ~-oleEin copolymer having a density of from 0.916 to 0.930 g/cm3 and a melt index of from 0.3 to I dg/min, said ethylene-vinyl acetate copolymer having a weight ratio of ethylene -to vinyl acetate of from 2.2:1 to 24:1 and a melt index of from 0.2 to 10 dg/min, said blend having a weight ratio of linear ethylene C~Clo ~-olefin coplanar to ethylene-vinyl acetate copolymer of from 1.2:1 to 9:1, said sealant film briny on the inside of the pouch.
In a preferred embodiment the weight ratio of ethylene-C~-C10 a -olefin copolymer to ethylene vinyl acetate copolymer is from 2.33:1 to 9:1.
In another embodiment the blend of ethylene-C4-Clo ~-olefin copolymer and ethylene-vinyl acetate copolymer has admixed -therewith from 13 to 18 parts of a high pressure polyethylene per 100 parts of said blend, said high pressure polyethylene having a melt index in -the range of 2 to 10 dg~min and a density of from 0.916 to O.g24 g/cm3.
In a further embodiment -the base film is selected from nylon 66, nylon 6, nylon 66~6 copolymer, nylon 6/10 copolymer, nylon 6/11 copolymer and nylon 6/12 copolymer.
Preferably the base film is nylon 66~ nylon 6 or nylon 66/6 copolymer.
In yet another embodiment, the base film and the sealant film have a layer of polyvinyldiene chloride (PVDC~
interposed there between In another embodiment the laminate comprises a base film sandwiched between two sealant films.
In a further embodiment -the plowable material is an oil, especially vegetable oil or motor oil and the base film it a nylon film.
The present invention also provides, in a process for making pouches filled with a plowable material on a vertical form and fill machine, in which process each pouch is made from a flat web of film by forming a tubular film therefrom with a longitudinal seal and subsequently flatten-in the tubular film at a eeriest position and transversely heat sealing sail tubular film at the flattened position, filling the tubular iamb with a predetermined quantity of plowable material above said first position, flattening the -tubular film above the predetermined quantity of plowable material at a second position and transversely heat sealing said tubular film at the second position, the improvement comprising making the pouches from a flat web of film made from 60 to 90 parts ethylene-C~-Clo -olefin copolymer having a density from 0.916 to 0.930 g/cm3 and a melt index from 0.3 to 2.0 dg/min admixed with 10 to 40 parts ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate of prom 2.2 to 24 and a molt index of from 0.2 to 10 dg/min.
In a preferred embodiment the film web used in the process is made from the blend of the linear ethylene-C4-Clo ~-olefin copolymer and ethylene-vinyl acetate copolymer, blend has admixed therewith from 13 to 18 parts of a high pressure polyethylene having a density in the range of 0.916 to 0.924 g/cm3 and a melt index in the range of 2 to 10 dg/min per 100 parts of said blend.
In another embodiment the ethylene-C4-Clo -olefin is selected from ethylene-butene or ethylene-octene Capella-men, especially ethylene-octene copolymer.
The linear ethylene-C4-Cloa -olefin copolymer use-fur in the present invention may be made from ethylene and an ~-olefin by a process disclosed in Canadian patent 856 137 which issued 1970 November 7 to WOE. Baker, IoC~B~ Saunders and JAM. Stewart. The linear ethylene~C4-Cl~ a-olefin copolymer may also be made by other processes known to those skilled in the art.
The ethylene-C4-Clo ~-olefin copolymer, ethylene-vinyl acetate copolymer and high pressure polyethylene are often available in pellet form.
Blends of the pelleted polymers may be fed into a film exterior and extruded into film form. A preferred film manufacturing method is the so-called blown film process disk closed in Canadian patent 460 963 issued 1949 November 8 to I Fuller. Films may also be made using an internal or external cooling mandrel with the blown film process, as disk closed for example in Canadian patent 893 216 issued 1972 February 15 to M. Boeing and TV Thomas. The internal cool-in mandrel brown film process is preferred. The copolymers, and high pressure polyethylene if present, may be blended prior to feeding to the film extrude hopper, or may be blended at the time of extrusion just prior to melting in the extrude, or alternatively may be melt blended in the extrude.
It will be understood by those swilled in the art that additives e.g. US stabilizers may be added to the ethylene polymers from which pouches of the present invention are made.
The film, after manufacture, is slit longitudinally into appropriate widths. The width determines the diameter of the tube formed on the vertical form and fill machine.
Preferably, film having a thickness of 51 to 127 em in thickness, especially 63 to 76 em in thickness, is used for the pouches of the present invention.
Pouches containing plowable materials may then be formed in the general manner described hereinbeEore on a vertical form and fill machine e.g. Prepay IS-2 or IS-6 liquid packaging machine, using the ethylene-C~-Clo Olin copolymar/ethylene-vinyl acetate copolymer film described herein.
When the film is a single layer or comprises a base film sandwiched between two sealant films, the pouch may have a fin seal or a lap seal. When the film comprises a base film and a sealant film, the pouch has a fin seal, and the sealant film is on the inside of the pouch.
g When the pouch is made from a laminate as described herein before, the transverse sealing device may more advent-ageously comprise two sealing elements and a severing element as described in US patent 1 377 149 granted 1975 April 9 to RYE. Petersen. With such a sealing device two transverse seals are made across the tubular film above and below the transverse sections described hereinhefore and the tubular film is severed between the two transverse seals.
Film laminates as described herein, having nylon, particularly nylon 66, nylon 6 or nylon 66/6 copolymer base film are particularly desirable for packaging oleagenous liquids e.g. cooking oil, motor oil. The nylon film may be cast or oriented.
As indicated herein before examination of melt strength, hot tax strength and heat seal strength data for the linear ethylene-C4-Clo ~-olefin copolymer/ethylene-vinyl acetate copolymer blends used in the present invention leads one skilled in the art to believe that there would be no improvement in the number of leakers with pouches from such blends compared to that experienced with pouches made from a blend of linear ethylene-butene copolymer and high pressure polyethylene. In order to illustrate the lack of correlation between melt strength, hot tack strength and heat seal strength with pouch performance, several samples of films, were taken and melt strength, hot tack strength and heat seal strength were measure. 2 lithe pouches of water were made using such films and the number of leakers determined by means of a drop test. In the drop test the pouches were dropped end-wise 152.4 cm onto a concrete floor.
Melt strength, is the weight of extradite which will remain suspended for a period of 3 minutes from -the orifice of a standard melt index tester (ASTM Procedure D1238-79). Heat seal strength is determined using a peel strength test similar to that used in ASTM Procedure D903 on a sample of film sealed using a Sentinel* heat seal apparatus *denotes trade mark.
Hot tack strength may be determined ho ASTM Procedure ~3706.
TABLE I
Heat Seal Hot Tack smelt Strength Strength %
Strength 12.7mm 25.4mm Seal Film* (g/3mln) 180C 190CFailures A 0.31 2080 300 11.6 B 0.63 2040 300 2.3 C 0.38 2300 300 1.7 D 0.29 1950 800 10.3 E 0.49 1397 500 0.4 Film A is 76 em in thickness and is made from a blend of 85 parts of a linear ethylene-~-butene copolymer having a density of 0.919 g/cm3 and a melt index of 0.75 dg/min and 15 parts of a high pressure polyethylene having a density of 0.918 g/cm3 and a melt index of 8.5 dg/min.
Film B is 76 em in thickness and is made from a blend of 85 parts of the blend of Film A and 15 parts of an ethylene-vinyl acetate coplanar having a melt index of 0.35 dg/min and a vinyl acetate content of 12 wit%.
Film C is 76 em in thickness and is made from a blend of 85 parts of the blend of Film A and 15 parts of an ethylene-vinyl acetate copolymer having a melt index of 0.7 dg/min and a vinyl acetate content of 18 wit%.
Film D is 51 em in thickness and is made from an ethylene-~-octene copolymer having a density of 0.918 g/cm3 and a malt index of 0c84 dg/min~
Film E is 51 em in thickness and is made from the ethylene-~-octene copolymer of Film D and 20 wit% of the ethylene-vinyl acetate of Film B.
Pouches made from Films B, C and F are within the scope of the present invention.
From the values of melt strength, ho-t tack strung and heat seal strength data it would be expected that the ethylene-~-olefin copolymer/ethylene-vinyl acetate copolymer and, optionally, high pressure polyethylene blend film would show little, if any, advantage over the ethylene-butene copolymer/high pressure polyethylene blend film.
The following examples further serve to illustrate the invention.
Example l The following resins and/or resin blends were evaluated for their performance as liquid packaging films:
U. 85 parts of an ethylene-butene coupler having a density of 0.919 g/cm3 and a melt index of 0.75 dg/min blended with lo parts of a high pressure polyethylene having a density of 0.918 g/cm3 and a melt index of 8.5 dg/min;
V. 85 parts of the resin blend in U in turn blend-Ed with 15 parts of an ethylene-vinyl acetate copolymer having a melt index of 0.35 dg/min and a vinyl acetate content of 12 wit%;
W. 85 parts of the resin blend in U in turn blend-Ed with 15 parts of an ethylene-vinyl acetate copolymer having a melt index of 0.7 dg/min and a vinyl acetate content of 18 White.
Pouches made from blend U is not within -the scope of the present invention and exemplifies the prior art.
The resins or resin blends were extruded at a melt temperature of 232C into films of various gauges at 409 kg/hr using a extrude equipped with a 81.3 cm diameter circular die and an internal film cooling mandrel.
The films were processed into 2 lithe pouches, substantially filled with water, using a Prepay IS-6 liquid packaging machine. The pouches were subsequently tested for seal integrity by dropping them from a height of 152.4 cm and determining the percentage seal failures.
% Seal Failures Film Gauge: 51 em 76 em 102 em Blend V 100 11.6 11.3 V 0.9 2.3 2.7 W 1.0 1.7 0.3 Example 2 Resin composition U of Example I above was blended with a number of ethylene-vinyl acetate copolymers (ETA
resins) outlined below and extruded into films 76 us in thickness. The resin blonds were extruded at a melt tempera-lure of 221C, at a rate of 38~6 kg/hr trough a 22.9 cm diameter circular die The films were processed into 1.3 lithe pouches, substantially filled with water, using a Prepay IS-6 liquid packaging machine. The pouches were sub-sequently tested or seal integrity by dropping them from a height of 152.4 cm. and determining the percentage seal failures.
Wit %
EVA resin Vinyl Acetate Melt Index in the EVA % Seal Sample _(dg/min) Resin Failures U~15% EVA I 0.3 12.0 2 U-~15% EYE II 1~2 7.5 40 U+30% EVA II 1.2 7. 5 23 u+a,5~ EVA II 1.2 7.5 5 lo U+30% EVA III 0.8 9.5 38 U~15% EVA IV 3.0 28.0 0 U~15~ EVA V 0.7 18.0 0 U+30% EVA VI 7.0 9.0 7 U-~45% EYE VI 7 . 0 9 . 0 3 U+15% EVA VII 8.0 18.0 5 Example 3 The following resins and/or resin blends were evaluated for their performance as liquid packaging films:
U, 85 parts of an ethylene-butene copolymer having a density of 0. 919 gm/cm3 and a melt index of 0.75 dg/min blended with 15 parts of a high pressure polyethylene having a density of 0. 918 gmfcm3 and a melt index of I 5 dg/min, Y. 85 parts of an ethylene-octene copolymer having a density of 0.918 g/cm3 and a melt index of 0 . 84 dg/min blended with 15 pats of an ethylene-vinyl acetate copolymer having a melt index owe 3 dg/min and containing 2 8 wit% vinyl acetate, Z. 70 parts of an ethylene-octene copolymer having a density of 0.918 g/cm and a melt index of 0.84 dg/min blended with 30 parts of an ethylene-vinyl acetate copolymer having a melt index of I 2 dg/min and containing 7.5 wit%
vinyl acetate.
Pouches made from Blend U it not within the scope of the present invention and exemplifies the prior art.
The resins were extruded at a melt -temperature of 221C at a rate of 38.6 kg/hr. through a 22.9 cm diameter circular die, and the resulting blown film was cooled by an internal cooling mandrel. The films were subsequently processed into 1.3 lithe pouches containing 103 liters of water, using a Prepay IS-6 liquid packaging machine. The pouches were subsequently tested for seal integrity by dropping them from a height of 152.4 cm. and determining the percentage failures.
Blend% Seal Failures Y O
Z O
Claims (10)
1. A pouch containing a flowable material said pouch being made from a sealant film in tubular form and having transversely heat-sealed ends, said film being made from a blend of a linear ethylene C4-C10-.alpha.-olefin copolymer and an ethylene-vinyl acetate copolymer, said ethylene C4-C10-.alpha.-olefin copolymer having a density of from 0.916 to 0.930 g/cm3 and a melt index of from 0.3 to 2.0 dg/min, said ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate from 2.2:1 to 24:1 and a melt index of from 0.2 to 10 dg/min, said blend having a weight ratio of linear ethylene-C4-C10-.alpha.-olefin copolymer to ethylene-vinyl acetate copolymer of from 1.2:1 to 9:1.
2. A pouch according to Claim 1 wherein the weight ratio of linear ethylene C4-C10-.alpha.-olefin copolymer to ethylene-vinyl acetate copolymer is from 2.3:1 to 9:1.
3. A pouch according to Claim 2 wherein the blend of linear ethylene C4-C10-.alpha.-olefin copolymer and ethylene-vinyl acetate copolymer additionally contains from 13 to 18 parts of a high pressure polyethylene having a density in the range of 0.916 to 0.924 g/cm3 and a melt index in the range of 2 to 10 dg/min per 100 parts of said blend of copolymers.
4. A pouch according to any one of Claim 1, Claim 2 and Claim 3 wherein the ethylene C4-C10-.alpha.-olefin copolymer is ethylene-.alpha.-butene or ethylene-.alpha.-octene copolymer.
5. A pouch according to Claim 1 wherein the film has a thickness from 38 to 127 µm.
6. A pouch according to Claim 5 wherein the film thickness is from 51 to 127 µm and the pouch contains from about 1.25 to 2 litres of the flowable material.
7. A pouch according to any one of Claim 2, Claim 3 and Claim 6 wherein the flowable material is a liquid or an emulsion.
8. A pouch containing a flowable material said pouch being made from a film in tubular form and having transversely heat-sealed ends, said film comprising a laminate of a base film and a sealant film, said base film being selected from the group consisting of nylon film, polyethylene terephthalate film, polyvinylidene chloride film, polyvinylchloride film, polyacrylonitrile film, polystyrene film and saponified ethylene vinyl acetate film and said sealant film being made from a blend of a linear ethylene C4-C10-.alpha.-olefin copolymer and an ethylene-vinyl acetate copolymer, said ethylene C4-C10 .alpha.-olefin copolymer having a density of from 0.916 to 0.930 g/cm3 and a melt index of from 0.3 to 2.0 dg/min, said ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate of from 2.2:1 to 24:1 and a melt index of from 0.2 to 10 dg/min, said blend having a weight ratio of linear ethylene C4-C10 .alpha.-olefin copolymer to ethylene-vinyl acetate copolymer of from 1.2:1 to 9:1 said sealant film being on the inside of the pouch.
9. A pouch according to Claim 8 wherein the base film is selected from the group consisting of nylon 66, nylon 6, nylon 66/6 copolymer, nylon 6/10 copolymer, nylon 6/11 copolymer and nylon 6/12 copolymer.
10. A pouch according to Claim 8 or Claim 9 wherein the laminate comprises a base film sandwiched between two sealant films.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB82/016101 | 1982-06-02 | ||
| GB8216101 | 1982-06-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1211083A true CA1211083A (en) | 1986-09-09 |
Family
ID=10530801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000429355A Expired CA1211083A (en) | 1982-06-02 | 1983-05-31 | POUCHES MADE FROM BLENDS OF ETHYLENE-.alpha.-OLEFIN COPOLYMERS AND ETHYLENE-VINYL ACETATE COPOLYMERS |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1211083A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5288531A (en) * | 1991-08-09 | 1994-02-22 | The Dow Chemical Company | Pouch for packaging flowable materials |
-
1983
- 1983-05-31 CA CA000429355A patent/CA1211083A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5288531A (en) * | 1991-08-09 | 1994-02-22 | The Dow Chemical Company | Pouch for packaging flowable materials |
| US5364486A (en) * | 1991-08-09 | 1994-11-15 | The Dow Chemical Company | Pouch for packaging flowable materials |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4503102A (en) | Pouches of ethylene-α-olefin copolymer/ethylene-vinyl acetate copolymer blends | |
| US4521437A (en) | Pouches of ethylene/octene-1 copolymer film containing a flowable material | |
| CA2151589C (en) | Pouches of ethylene copolymer film containing a flowable material | |
| EP0743902B1 (en) | Multilayer ethylene copolymer film | |
| AU668879B2 (en) | Pouch for packaging flowable materials | |
| KR100494039B1 (en) | Pouches containing fluent materials, film structures used therein and methods for making such pouches | |
| EP0865361B1 (en) | Novel pouches for packaging flowable materials in pouches | |
| US6117465A (en) | Pouches for packaging flowable materials | |
| AU7246694A (en) | Pouch for packaging flowable materials | |
| GB2121062A (en) | Heat sealable plastics pouches | |
| EP0998388B1 (en) | Pouches for packaging flowable materials | |
| CA1211083A (en) | POUCHES MADE FROM BLENDS OF ETHYLENE-.alpha.-OLEFIN COPOLYMERS AND ETHYLENE-VINYL ACETATE COPOLYMERS | |
| USRE30726E (en) | Polymer film having linear tear properties | |
| WO1999006476A1 (en) | Pouch for packaging flowable materials | |
| GB1592425A (en) | Polymer film having linear tear properties | |
| MXPA98004440A (en) | Novedos bags to pack fluible materials in bol | |
| MXPA99007377A (en) | Pouches for packaging flowable materials | |
| JP2002523310A (en) | Liquid package with improved leak frequency performance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |