Free Redacted Document - District Court of Delaware - Delaware

Case 1:04-cv-01278-KAJ

Document 174-4

Filed 09/27/2005

Page 1 of 9

f

United States Patent
Dallmann et aL [541

{197

[ill , Patent Number: [451 Date of Patent : -

4!572,854
Feb . 25, 1986

MUI nLAYER FILM WITH A GAS AND AROMA BARRIER LAYER AND A PROCESS FOR THE PREPARATION AND APPLICATION THEREOF
Inventors : Herman Dallmann , Wiesbaden; Hans J . Palmer, Walluf, both of Fed . Rep. of Germany

FOREIGN PATENT DOCUMENTS
0062815 3/1982 European Pat. CIEs. . 2931435 2/1981 Fed . Rep. of Germany 3120308 8/1984 Fed. Rep. of Germany , 1567189 10/1976 United Kingdom . 2425839 8/1978 United Kingdom . Primary Examiner--Edith Buffalow Artnrney, Agen6 or Firm---Schwartz, Jeffery, Scbwaab, Mack, Blumenthal a Evans [571 ABSTRACT The invention concerns a multilayer, preferably sealable film, comprising one or more inner layers ; more specifically, ( 1) an inner barrier layer D containing a saponified ethylene-vinyl acetate polymer having 15 to 60 mole % ethylene units and being saponified to at least 90 mole %, and (2) at least one layer immediately adjacent to the surface of the barrier layer D, which layer is an adhesion- promoting layer C and comprises a modified polymer or the modified polyolefin . All layers of the film are oriented at least biaxially, under identical conditions . On one side of the barrier layer D, adjacent to the first adhesion-promoting layer C, a first layer B is located, and an optionally, a sealable layer A, is adjacent thereto . Layer B contains a polypropylene homopolymer and/or a propylene copolymer and/or the material of the layer C and/or the material of the optional layer A. Also disclosed is a process for the preparation of a multilayer film as described, and its use, in particular, in the packaging of oxygen-sensitive goods .

(75]

[731 Assignee-

Hoechst Aktiengesellschaft, Frankfurt am Main, Fed . Rep . of Germany

[21] Appl . No ., 582,552
[22) Filed: Feb. 25, 1986

[30] Foreign Application Priority Data Feb . 23, 1983 [AE] Fed. Rep . of Germany . ...... 3346189 (51] [52] [58]
1561 4 .212,956 4,254,169 4,367, 305 4,400,428

Int . C1.4 . . . . . . . ... . . . . .. ... . . . . . . . ... . . . . . . . . .. . . .. . .. B32B 27/00 U.5. C1 . . . .. . . .. . . . . .. . .. . .. . . .. .. . . . . . . .. . .. . 428/3S;428/349; 428/516; 428/518; 428/520, 156/244 .1I Field of Search . . . . ., . . . .. . .. ... 428/516,349,35,518, 428/520,522 ; 156/244 .11
References Cited

U.S. PATENT DOCUMENTS
7/1980 3/1981 1 / 1983 8/1983 Katsura . ... .. . .. . . . . . . . . . ....... . .. .. ... 525/60 Schroeder . . . .. . . . . . . . . . ....... ... .. . .. 428/35 Satoh et al . ... . . .. . . . . . . . . . . .. . .... . 524/398 Rostnthal . . . .. . .. .. . .... ...... .. . . . . 428/349

30 Claims, 6 Drawing Figures

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Case 1:04-cv-01278-KAJ Document 174-4 Filed 09/27/2005 Page 2 of 9

U.S. Patent

Feb. 25, 1986

4,5'72,854

FIG . I

e c

A

FIG . 2

A W(B+C) D c

FIG. 3
"N" ANN VANN NN

B"' (A+c+ 1 B )

FIG. 4

D

c
e"" (c+ B)

FIG . 5

c

D

FI G. 6 .



Case 1:04-cv-01278-KAJ

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Page 3 of 9

4,572,854
2 film laminates, including those with barrier layers comMULTILAYER FILM WITH A GAS AND AROMA prised of an ethylene-vinyl alcohol copolymer. BARRIER LAYER AND A PROCESS FOR THE In accomplishing the foregoing objects, there is proPREPARATION AND APPLICATION THEREOF vided in accordance with the present invention a multi5 layer film which comprises (a) an inner barrier layer D BACKGROUND OF THE INVENTION comprised of a saponified ethylene-vinyl alcohol co-, The present invention relates to a multilayer, prefers- polymer which contains about 15 to about 60 mole % bly sealable laminated film having a barrier layer ethylene units and which is saponified to at least approximately 90%, said inner barrier layer presenting a therein, as well as to a process for its manufacture and lil first surface and a second surface ; (b) on at least one of use . A multilayer film having a barrier layer made of a said first and second surfaces, an adhesion-promoting material such as that used in the present invention is layer C comprised of a modified polyolefin ; and (c) adjacent to said adhesion-promoting layer, a layer B described in German Offenlegungssehrift No . 26 44 209 (equivalent to British Patent Specification No . is comprised of at least one polymer selected from the 1,567,189) . The disclosed film has a multilayer structure group consisting of a propylene homopolymer, a propyincluding a base comprised of polypropylene, an inter- lene copolymer, and said modified polyolefin, wherein mediate layer comprising a modified polyolefin pro- all of the layers of the multilayer film are biaxially orivided on the base film, and a barrier layer to reduce ented under substantially the same stretching condi. oxygen permeability, with a heat seal layer optionally 20 tions applied to the barrier layer . The film is prepared, ac- In addition, there is provided a process for manufaccording to the aforementioned German Offenlegungss- turfing multilayer film which comprises the steps of reproviding at least three separate melts comprising, chrift, by applying to the transversely or longitudinally spectiveiy, (i) a saponified ethylene -vinyl alcohol coaxiaJly oriented polypropylene base film a two-layer polymer which contains about 15 to about 60 mole melt comprising the polymers of the intermediate layer 2 and the barrier layer . The composite film thus obtained .5 ethylene units and which is saponified po at least approximately 90%, (ii) a modified polyolefin, and (iii) is then oriented by stretching it in the transverse direcOne selected from the group consisting of a polypropyltion. The beat sealable layer is applied subsequently, i .e., cue homopolymer, a polypropylene copolymer and said after the preparation of the three-layer composite film, of olefin; (b) oite; and ng said melts to proin a further step and is therefore essentially unoriented . 30 modified p Y and As As a result, different orientation values are obtained for ' ing said multilayer composite thereafter dace a multilayer composite, and bath transversely and transversely stretchthe layers of the base film, the intermediate / barrier longitudinally. layer, and the heat seal layer, respectively . It has now been found that the above-discussed film is BRrEF DESCRIPTION OF THE DRAWINGS frequently incapable of satisfying requirements con- 35 In the drawings, FIGS . 1--6 each show, respectively, cerning gas barrier properties, water resistance, and a cross-sectional view of a different multilayer film oth er p hysica proper t ies, which requirements have t within the present invention . become increasingly stringent . To improve the sliding properties of the film disDETAILED DESCRIPTION OF PREFERRED closed by German Offenlegungsschrsft No . 26 44 209, 40 EMBODIMENTS European Patent Application No . 0 062 815 describes a The multilayer film of the invention has a gas and process to modify the outer sealing layer by means of aroma barrier layer D of the aforementioned copolymer special additives . The disclosed modification of the and additional layers on either side of said layer, Outer sealing layer does not improve the gas barrier wherein at least one of the two surface layers of the properties and water resistance of the film . Further- 45 multilayer film preferably comprises a sealable outer more, the individual layers are not oriented under the layer A . Directly on at least one f the two surfaces of same conditions. the barrier layer D, respectively, h layer C is provided, On the other hand, the existing sealable, multilayer said layer C representing an adhesion-promoting layer films having a barrier layer comprised of ethylene-vinyl 50 consisting essentially or exclusively of adhesion-proalcohol copolymers cannot be produced by extruding muting polymers, or alternatively, comprising a mixture all of the layers simultaneously to obtain an orientation of polymers containing an adhesion-promoting polymer (B', B", B"', B," .) . of all layers by stretching under identical conditions . For the purposes of the following description, one SUMMARY OFTHE INVENTION 55 surface of barrier layer D facing optional sealable outer It is therefore an object of the present invention to layer A will be arbitrarily designated the "first surface improve the physical properties of multilayer film lami- of barrier layer D ." Between optional sealable outer nates, particularly their barrier properties against atmo- layer A and the fast surface of the barrier layer D, a spheric oxygen and aromas, such as flavors, ordors, etc . first layer B is provided which is thicker than layers A It is a further object of the present invention to extend 60 and D and which performs the function of a base or the sealing range of multilayer laminates to which are support . Between the first layer B and the barrier layer applied outer sealing layers. D, the first adhesion-promoting layer C is present . The It is another object of the present invention to pro- thickness of the layer B, which preferably amounts to vide improved multilayer laminates comprising one or about 10 to 20 microns, is essentially responsible for the more barrier layers containing ethylene-vinyl alcohol 65 mechanical properties and dimensional stability of The copolymers . multilayer film, while the thickness of the optional It is yet another object of the present invention to layer(s) A and of layers C and D is relatively small, provide an improved process for producing multilayer primarily because of cost considerations, and is appro-

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Page 4 of 9

4,572,854
4 priately between about 1 micron and 3 microns (FIG . degree of at least about 90 mole %, preferably higher I). than about 96 mole % and in particula r approximately n In one embodiment, layers B and C comprise a com- 99 mole 90 . These copolymers include, for example, mon, homogeneous layer combining both of their thick- ethylene-propylene-vinyl alcohol copolymers and reacnesses, which layer (B') contains both the polymers of 5 tion products of ethylene-vinyl alcohol copolymers layer H and the polymers of the layer C (FIG . 2) . with lower aldehydes or ketones, as described, for exIn another embodiment, layer A and the first layer B ample, in German Offenlegungsschrift No . 29 31 035 are comprised of the same polymer mixture and form a and U .S . Pat· No . 4,212,936 . single layer which combines both of their thicknesses, The ethylene-vinyl alcohol copolymers may contain Layer B in this case ($") also has heat sealing proper- 10 water during extrusion, preferably in amounts of about ties. The aforementioned polymer mixture includes the I to 10% by weight . But to obtain a high orientation heat sealing polymer material of layer A and the polyeffect and, thus, a good gas barrier, it is preferable to mers of layer B (FIG . 3). have a water content less than 5%, preferably less than In yet another embodiment, only a single layer B"' is 3 .5%, and in particular, less than 2% by weight or appresent on the first surface of the barrier layer D, which 15 proaching zero . These values should be obtained espelayer is both heat-sealable and is attached with sufficient cially during the manufacturing of the film, immediately strength to barrier layer U . For this embodiment, a prior to the stretching process. mixture of polymers is used which includes the adheThe barrier layer D comprised of ethylene-vinyl al . lion-promoting material of the layer C and the heatcohol copolymers may contain monomer, oligomer, or sealing material of the layer A, and optionally, the poly- 20 polymer substances to improve its stretchability (i .e., to mers of layer B . The thickness of the single layer correinfluence crystallinity). The amount added in each case sponds to the total thickness of the alternative threeis controlled b the substances' compatiblyersuctofhelayrsA,BndC(FIG y (t .e ., he . 4) . the capacity for being worked in and mixed ) with the In still another embodiment, only a single layer B" . 25 principal component, and by the effect on the oxygen which includes C and 13, is found on barrier layer D barrier. Examples of such substances are compounds Heat-sealing is not used in this embodiment (FIG . S) . containing hydroxyl and/or carbonyl groups, such as The layers present on the opposite side of the barrier layer D, hereinafter designated the "second surface of trimethylolpropane, neopentyl glycol, and polyethylene glycol, and in particular substances which have D," include, for example, a layer each of A, D . and C, __ and are provided in configurations similar to those de- 30 barrier properties of their own, such as polyvinyl alcoscribed for the aforementioned embodiments of the first hols or polyamides . Mixtures of ethylene-vinyl alcohol surface of the barrier layer D (FIG. 6). Thus, combina- copolymers and about 0 .5 to 50% by weight of polyvitions provided in the second surface of D of the layers nyl alcohol with a hydrolysis degree higher than about A, B, and C; A and B' (B contains adhesion-promoting 80, in particular higher than or equal to about 88 mole material); and B" (B contains preferably heat sealing 35 %, and a viscosity of from about 0 .4X 10-2 o about .4x10-2 material) and C are all within the scope of the present 4 X 10-2 Pas, in particular from about 0 to I X 10-2 Ira .s, are preferred. invention . Polyamides are compatible with ethylene-vinyl alcoIt is preferable, however, for certain applications to hol copolymers over the entire miscibility range and -T eliminate the second sealable layer A and, possibly, the second layer B from the second surface of D . In such a 40 therefore are readily worked in. Such mixtures (blends) have already been described in European Patent Applicase, a sealable surface may be produced on the second cation No. 00 63 006. The films produced from them, surface only at a later time, i .e ., after extrusion . This however, are not oriented . Of the different polyamides may be accomplished, for example, by partial- or fullavailable, the 6,12- and 6,6-copolyamides with a softensurface application effected by the printing-on of a sealable layer comprised of specially formulated polyole- 45 ing point of less than about 210" C . are especially suitable . Preferably, about 10 to 60% by weight and even fims. At temperatures below 100' C., this layer is prefermore preferably about 10 to 20% by weight of a polyably sealable against itself and against other sealable mer or copolymer are added. layers comprised of polyolcl-ans . This printed-on sealThe mixing ratio is chosen so that the film is readily able layer may be located on the existing layer C or 13, or it may be applied subsequently to a sealable outer 5o stretchable biaxially at the selected stretch parameters, with the gas barrier being unaffected, or being only layer A, if, for example, it should be discovered that the slightly affected . layer A is not particularly advantageous for a given Initial extruded granules may be prepared from the special use . An ethylene-vinyl acetate copolymer is granulated mixture of the polymers by known means . suitable as the preferred principal component for the printed-on sealable layer, since 9t permits the mainte- 55 Preferably, the mixtures of granules are processed directly, for example, with an extrusion screw having an nance of relatively low sealing temperatures i .e ., under especially good homogenizing effect, i .e., a screw with 100° C . Alternatively, compounds that are adhesive at a shear portion. even lower temperatures, such as natural rubber, may be used as additional components or as other principal The barrier layer D comprised of ethylene-vinyl alcomponents . The additional components impart a seal- 60 cohol copolymers may contain further additional addiing capability to the printed-on layer against layers of tives in the form of monomers, oligomers or polymers the same material with the application of pressure only . which promote adhesion to adjacent layers . Examples Such adhesives are known, for example, as pressure- of such additional substances are graft-modified polysensitive adhesives or contact adhesives . olefins, ethylene-acrylic acid copolymers, ionomers, The barrier layer D serves as a gas barrier, in particu- 65 and olefin copolymers . lar an oxygen or aroma barrier, and is comprised of an In place of one barrier layer, the film may contain ethylene-vinyl alcohol copolymer with an ethylene several oriented barrier layers which are preferably content of about 15 to 60 mole % and a saponification connected by an adhesion-promoting layer .

3



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4,572,854
V

5

The adhesion-promoting layers C may advanta. very different requirements concerning sealing propergeously contain a graft-modified olefin homopolymer ties, combinations of copolymers and/or terpolymers or copolymer, a partially saponified ethylene-vinyl alwith polymers, low molecular resins and polydiorcohol copolymer with a low degree of saponification, ganosiloxanes are preferably used . The density of the or mixtures thereof with other polyolefins . Particularly 5 sealing layer polymers is preferably within a range of preferred are polypropylene homopolymers or copoly. about 0.89 to about 0.96 g/cm3, the melt index within mers graft-modified with carboxylic acids or their anhyabout 0.1 to about 16 g/]0 min . and 2.16 kg/cmz (DIN drides . 53735), and the softening point within about 60° to The polymer of layer B may be comprised of a propyabout 180' C . (DIN 1995-44), and particularly preferalene homopolymer or copolymer with a melting point 10 bly between approximately 80' and 140° C . of about 140' C . or higher, preferably about 150° C . or The layer thickness of a sealable outer layer A is higher. Examples of suitable polymers for layer B are preferably within about 0 .1 micron to about 10 microns, isotactic polypropylenes with a heptane soluble propor . particularly preferably within about I micron to about 3 tion of 15% by weight or less, ethylene copolymers microns . with propylene and an ethylene content of up to 15% 15 As described above, sealable layers may subsequently by weight, and copolymers of propylene with butene, be applied on one or both sides to the other layers, i .e ., pentene, hexene, heptene, octene, and/or other olefins . after coextrusion : Preferably, the sealable layers have a Mixtures of the above-mentioned copolymers may also sealing-onset temperature lower than that of layer A, be used.. The melt flow index (MF'I) of the polypropylor, alternatively, seal under the effect of pressure alone. ene polymers advantageously used in this context is 20 These sealing layers, which after the preparation of the within a range of about 0.5 g/10 min . to about 8 g/10 film may preferably 'be applied in a single working step min. at 230' C . and 2 .16 kp/cmx (DIN 53735). The during the printing of the film, may have layer thick- . polypropylene polymers may contain additives , such as nesses of about 0 .1 micron to about 10 microns, preferastabilixers, pigments, and low molecular weight , combly about 0.1 micron to about 5 microns. ' patible resins or polymers. 25 These heat sealable layers , deposited from solutions Of the additive pigments, those lending the film a or dispersions, may contain as principal components pearly lustre are preferred . Examples of such pigments acrylates, ethylene-vinyl acetate copolymers, or ionoare titanium dioxide, calcium carbonate , and silicon mers, and the cold -sealing layers may contain natural dioxide. The pigment particle size is preferably within a rubber latex . They may also contain, similarly to layer range of about 0 .1 micron to about 20 microns, the 30 A, additives such as lubricants and slip- and antiblockamount added preferably in the range of about 1 to ing-agents. To improve adhesion to the film and abraabout 25% by weight . Examples of low molecular, sion-resistance, the layers may be anchored on the film compatible resins are petroleum resins, terpene resins, by means of an adhesion-promoter, for example, one and natural oil resins obtained in the cracking of naphcontaining polyurethane. A corona treatment of the tha or gas oil . The resins may be' hydrated and/or modi- .35 film is in many cases sufficient to improve the adhesion fled by the introdtiction o special monomers prior to of this additional layer or layers . polymerization . The films provided with cold - sealable layers are prefThe working-in of the resins to prepare mixtures to erably coated on the reverse side with a dehesive laccomprise layer B is effected by convenional methods . quer, i .e ., with an anti-adhesive agent . Examples of The amount of resin added is controlled by its effect on 40 suitable dehesive lacquers are those comprised of polyoptical properties and stretchability, More than 20%a by amines or vinyl-containing siloxanes , which may also be weight with respect to the propylene polymers is not cross-linked . necessary for processing reasons, for example, with low The multilayer film according to the present invenmolecul ar resins, such as terpene resins . tion, when stretched at least biaxially, preferably has a The film is preferably sealable, while the sealable 45 total thickness of about 10 to about 100 microns, preferlayers on either side of barrier layer D may have differ- ably about 15 to about 35 microns, wherein the major cut thicknesses and compositions . part of the thickness is made up by B layer(s) . The optionally but preferably present scaling-layer The film according to the present invention produced polymer of layer A is advantageously comprised of at by coextruding layers B, C, D, C (B optional), or A, B, least one polymer selected from the group consisting of 50 C, D, C, (B and A optional) and then stretching, at least a homopolymer or a copolymer of an olefin, preferably biaxially, has an excellent gas- and aroma barrier capacan alpha-olefin, an ionomer, a mixture of these or of ity in comparison with a nonoriented film stretched at different polyolefns, and an ethylene-propylene-C,, high temperatures or high atmospheric humidities, toterpolymer, where C . denotes an alkylene monomer gether with good mechanical properties . It is therefore having n carbons, n being an integer ranging between 4 55 outstandingly suitable for the packaging of oxygen-senand 10. Preferably, the sealable outer layer A is com» sitive food, luxury, e .g., tobacco, and pharmaceutical prised of a low or high density ethylene homopolymer items . or an ethylene copolymer . Especially preferred are By the addition of pigments such as calcium carbonethylene-propylene copolymers and ethylene-propy- ate to the polymers of the layers B or C, at) opaque film lene-butylene terpolymers, wherein the ethylene con- 60 is obtained, tent is preferably from about 0 .1 to about 15% by Providing the multilayer film of the present invention weight and the butylene content is within about 1 to with low temperature sealing or cold-sealing layers about 2010 by weight. opens up new fields of application, for example, in the To improve its sealing capability, scratch resistance packaging of temperature-sensitive luxury items . and running safety in high speed packaging machines, 65 The control of gas permeability by means of layer the sealing layer polymer of layer A may contain conthickness, formulation, and degree of stretching, toventional additives, such as low molecular resins and gether with the provisions of a wide sealing range, lubricants, slip and antibloeking- agents. To optimize the permit other industrial applications . Examples are the



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4,572,854 7 S wrapping of synthetic plastic piping for heating purMFI of 10 g/10 min, a density of 0.89 g/cm3 and a poses and the like , in order to reduce the oxygen permemelting point of 153 ' C . ; and (4) for layer D a mixture ability. of an ethylene -vinyl alcohol copolymer with an ethylTo produce the films of the present invention by ene content of 42 molar % and a saponification degree means of coextrusion, successively flanged distributor 5 of 99.5 mole % and 30 % by weight of a polyvinyl alcosystems may be coupled with a T-slot die . The layout of hol with a hydrolysis degree of 88 mole %, was prethe distributor systems, together with the number of pared by coeztrusion . The melt was extruded from a channels of the die, depends on the composite structure slot die with a width of 280 mm, a slot width of 1 .8 mm, desired . and a die temperature of 23 0 " C, onto a chill roll with a The production of a seven-layer film is appropriately 10 surface temperature of 10' C ., and was laid onto the carried out with the use of a three-layer die . In the case chill roll by means of a suction box and pinning (electric of a symmetric frlm structure, the melts of the polymers wire discharge) . The runout velocity of the chill roll for layers B . C, and D may be extruded through the was 4 .6 m/min . The film was next stretched with rolls center channel and the melts for the outer sealing layers longitudinally by a factor of 3 .8 with a roll temperature A simultaneously through the outer channels"onto a 15 of 130° C . and at an air temperature of 122' C. in a chill roll. stenter transversely by a factor of 7 . The surface temperature of the chill roll is preferably The resulting biaxially-stretched, 40 micron-thick below room temperature . The side of the melt facing film had a gas barrier layer of 1 .2 microns, and an oxyaway from the chill roll may be cooled additionally by gen permeability of 5 .8 cm3.d·bar at 20' C . and 0% means of air blowers . 20 relative humidity (r .F.).
The biaxial stretching of the film may be performed

EXAMPLE 2 simultaneously or in steps . In the preferred biaxial, step wise stretching process, stretching is initially carried The experiment described in FAample I was repeated out longitudinally by means of heated rolls and transwith the difference that the barrier layer was comprised versely thereafter with a stenter and then the film is 25 of a mixture of (a) an ethylene-vinyl alcohol copolymer heat-set Stretching temperatures are within the usual with an ethylene content of 29 molar %a, a saponificarange for polypropylene film . The longitudinal stretchtion degree of 99 .9 molar %, and a melting point of 188' ing temperature is appropriately within a range of about C.; and (b) 2D% by weight of a copolyamide with a 80' to about 150' C ., preferably within about 110' to melting point of 196' C, and a density of 1 .14 g/cm3 . about 130 ° C.; the transverse stretching temperature (air 30 The film thus obtained was stretched longitudinally temperature of the transverse stenter is advantageously by rolling at a temperature of 135' C . by a factor of 4.4 from about 100' to about 170' C ., preferably from about and by means of a stenter at 120" C . by a factor of 6 and 110' to about 130' C. heat treated at an air temperature of 160' C . in the set The longitudinal and transverse stretch ratios are condition. usually between 2 and 5, preferably between 3 and 5 for 3$ The resulting, oriented, clear film had a thickness of the longitudinal stretch ratio and from about 3 to 12, 28 microns, a barrier layer of0 .8 micron , and an oxygen preferably 6 to 10, for the transverse stretch ratio . permeability of 12.5 cm3/m2-d .bar at 93%n r.F. To optimize mechanical properties and the oxygen EXAMPLE 3 -","barrier properties, longitudinal stretching of the film may be carried out in two steps, or the longitudinal 40 The experiment described in Example 1 was repeated transverse stretching may be followed, prior to thermowith the difference that the barrier layer was comprised --fixing, by an additional longitudinal stretching, of a mixture of (a) an etbylene-vinyl alcohol copolymer Stretching is followed by a heat treatment in the with an ethylene content of 32 mole % and a saponificathermo-fixed or stress-relieved state in a temperature tion degree of 99 .6 mole % ; and (b ) 5% by weight of range of about 100' to about 180° C., preferably about 45 neopentyl glycol. 140' to about 175' C . Thus, the post-stretching heat The film obtained in this manner was stretched by treatment generally is at a temperature between about means of a roll stretch installation at 135' C_ by a factor 100' C, and a temperature less than the melting point of of 3 .2 in the longitudinal direction and subsequently at the material comprising barrier layer D or, if it is pres128' C. in a stenter by a factor of 5 .4 in the transverse ent, layer B. This heat treatment , also characterized as 50 direction . thermo- fixing , may be eliminated when the shrinkability The resulting 17 micron-thick film had a barrier layer of the film during heating is to be maintained . of 1 .1 micron and an oxygen permeability of 6 .9 The examples described below are illustrative only, cm3/m2-d-bar at 93 % rX, and do not restrict the scope of the present invention . EXAMPLE 4 All measurements of oxygen permeability were per- 55 formed with an OXTRAN 100 instrument of Matern A multilayer film, comprising (1) a mixture for layer Controls, Inc. B of polypropylene with a MFI of 9 g/10 mitt. at 230' C., 5 kp/cm2 and 20 % by weight of a terpene resin with EXAMPLE 1 a melting point of 125' C . ; ( 2) for layer C a polypropylA film sealable on both sides, comprising (1) an ethy- 60 ene modified with carboxylic acid anhydride with a lene-propylene copolymer for layer A having an ethyl density of 0 .9 g/cm3, a MFI value of 4 .7,S/10 min . (D ene content of 4 .1%, a MFI of 22 .4 g/l0 min, at 230' 1235-65 T), and a melting point of 165' C . ; and (3) an C./5 kp /cm2, and a melting point of 143' C. ; (2) for ethylene - vinyl copolymer for layer D with an ethylene layer B a mixture of a polypropylene with a MFl of 9 content of 42 mole % and a saponification degree of g/10 m in. at 230' C./ 5 kp/cm2 and a melting point of 65 99 .9 mole W was produced by coextrusion with a slot 162' C. and 20% by weight of a terpene resin with a die having a width of 480 mm and a slot width of 1 mm melting point of 125' C. ; (3) for layer C a polypropylene onto a chill roll with a diameter of 600 min and a surface modified with a carboxylic acid anhydride, having a temperature of IT C ., running at a circumferential ve-



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4,572,854 10 9 locity of 4.5 m/min. The film was conducted from the A sample of this film was sealed in an instrument chill roll to a three-roll stand running at 4 .5 m/min . and (Brugger Co .) with a 5 cm long, 12 cm wide sealing jaw froni there to a heated roll stretch installation . having 8 grooves, at 0 .5 s and 0.5 M.Pa . 'The film thus obtained was subsequently stretched The sealed joint strength measured after sealing of longitudinally by a factor of 3 at a temperature of 120°, 5 the layers against each other was 1 .5N/15 mm after 8 C . by means of rolls and in the transverse direction with days and I .9NI15 mm after storage for 6 weeks at room a stenter by a factor of 6, at 110' C . temperature. No string formation occurred upon the The resulting clear, biaxially-oriented film had a opening of the sealed joint . thickness of 33 microns, a gas barrier of 1 .1 micron, and What is claimed is : an oxygen permeability of 16 cm3/mLd ·b ar at 93% r .F. 10 1 . A multilayer film which comprises : (a) an inner barrier layer D comprised of a saponified EXAMPLES ethylene-vinyl alcohol copolymer which contains The experiment described in Example 4 was repeated about 15 to about 60 mole % ethylene units and with a mixture for the barrier layer of (1) an ethylenewhich is saponified to at least approximately 90%, vinyl alcohol copolymer with an ethylene content of 32 I5 said inner barrier layer presenting a first surface mole %, a saponification degree of 99.6 mole %, and a and a second surface; melting pint of 182" C ., and (2) 20% by weight of a (b) on at least one of said first and second surfaces, an copolyamide with a melting point of 204' C. adhesion-promoting layer C comprised of a modiThe film was stretched by a factor of 3 .1 at 131' C. by 20 fied polyoleftrt ; and rollers in the longitudinal direction and at an air temper(c) adjacent to said adhesion-promoting layer , a layer ature of 130° C . in a stenter transversely by a ,factor of H comprised of at least one polymer selected from 9 .5 and heat treated in the set condition at 150° C. the group consisting of a polypropylene homopolyThe resulting biaxially-stretched, clear filth had a mer, a propylene copolymer , and said modified thickness of 18 microns, a barrier layer of 1 .2 micron, 25 polyolefin, and an oxygen permeability of I I =3/m2-d-bar at 93% wherein all of the layers of said multilayer film are r.F. coextruded to form a multilayer composite , which is then biaxially oriented under substantially the same EXAMPLE 6 stretching conditions to form said multilayer film . The experiment described in Example 4 was repeated 30 2 . A multilayer film as in claim 1 , further comprising with the difference that for the barrier layer D a mixture a sealable layer A adjacent to at said layer l3. 3. A multilayer film as in claim 2 ;, wherein said layer was used of an (a) ethylene-vinyl alcohol copolymer with an ethylene content of 42 mole %, a saponification A and said layer B comprise a single layer compHsed of degree of 99,9 mole %, and a melting point of 162' C . ; a blend of the polymer components for said layers A and (b) 30% by weight of a polyvinyl alcohol with . a 35 and B . hydrolysis degree of 89 mole % . The film was stretched 4. A multilayer film as in claim 1, wherein said layer at 130' C . longitudinally by a factor of 2 .5 and at 120' C . C and said layer B comprise a single layer comprised of transversely by a factor of 7,5 . a blend of the polymer components of said layers C and The resulting clear, - biaxially-oriented film had a B. 5. A multilayer film as in claim 2, wherein said seal . thickness of 45 microns, a barrier layer of 1 .6 micron, 40 and an oxygen permeability of 15 .9 cm3/m2-d ·bar at able layer A comprises at .least one polymer selectedd from the group consisting of a homopolymer or a co93% r.F. polymer of an alpha-olefin ; an ionomer; a mixture of EXAMPLE 7 different polyolefins; and an ethylene-propylene-Ca Onto the film described in Example 6, 4 .3 g/cm2 of a 45 terpolymer where C,, denotes an alkylene monomer having n carbons, n being an integer ranging between 4 heat sealing lacquer comprised of an ethylene-vinyl and 10. acetate copolymer was applied by means of gravure6, A multilayer film as in claim 5, wherein said sealprinting. Following the sealing of a sample in a sealing apparaable layer A comprises an ethylene copolymer or an tus (Sentinel type) at a pressure of 0 .5 N/cm2 and a 50 ethylene-propylene-butylene terpolymer wherein the ethylene content is within the range of about 0 .l % and heating time of 0 .5 seconds, the following sealed joint about 15 % by weight and the butylene content is within strengths were obtained : the range of about 1% to about 20% by weight . 7 . A multilayer film as in claim 1, wherein each of Scaling Layer against Layer against 55 said first surface and said second surface of inner barrier Ternperatum Layer Side A of film layer D is provided with an adhesion -promoting layer C 60` C. 3 .3 N/15 nun 2.2 N115 mm adjacent thereto and a layer B adjacent to each layer C, so, C. 3,3 N/15 mm 2.3 N/15 mm respectively. too' C. 4.5 N115 mm 2 .2 N115 mm 8, A multilayer film as in claim 7, further comprising 6o a sealable layer A adjacent to each layer k3, respectively. EXAMPLE 8 9. A multilayer film as in claim 1, further comprising The film described in Example 6 was corona treated, a sealable outer layer facing at least one of said first then coated with (i) 0,5 g/cm2 of an adhesion promoter surface and said second surface of said inner barrier based on polyurethane and, following the evaporation 65 layer D. of the solvent with (ii) 2 g/cm2 (solids) of a cold-sealing 10, A in ultilayer film as in claim 9, wherein said seal . dispersion having a viscosity of 12 s (Ford-measuring able outer layer is adjacent to an adhesion-promoting cup 4 mm, 100 cm3, at room temperature . layer C.



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Document 174-4

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Page 8 of 9

4,572,854
12 11 . A multilayer film as in claim 9, wherein said seal 21. A multilayer film as in claim 1, wherein said layer . able outer layer comprises at least one polymer selected B further comprises finely distributed, solid pigment, from the group consisting of an ethylene-vinyl acetate particles in an amount ranging between about 1% and copolymer, an acrylate, and an ionomer. about 25% by weight, the size of said particles ranging 12. A multilayer film as in claim 10, wherein said 5 between about 0 .1 and 20 microns . layers C and A comprise a single layer, comprised of a 22 . A multilayer film as in claim 2, wherein said sealblend of the polymer components of said layers C and able layer A comprises at least one additive selected A. from an antistatic agent, a slip agent, a lubricant, and an 13. A multilayer film as in claim 8, wherein said layers antiblocking agent. C, B, and A provided on said first surface comprise a 10 23 . A multilayer film as in claim 1, further comprising single layer and said layers C, B, and A provided on said a low-temperature sealable layer applied to at least a second surface comprise a single layer . portion of one outer surface of said film, said low-tern14 . A multilayer film as in claim 1, wherein said inner perature sealable layer having a sealing-onset temperabarrier layer D comprises a mixture of an ethylene-vinyl tore lower than the sealing-onset temperature of said alcohol copolymer with about 0 .5 to about 50% by 15 sealable layer A . weight of a carbonyl-containing polymer . 24. A multilayer film as in claim 23, wherein said 15 . A multilayer film as in claim 14, wherein said low-temperature sealable layer comprises an ethylenecarbonyl-containing polymer is selected from the group vinyl acetate copolymer as its principal component . consisting of a polyamide and a copolyamide . 25. A multilayer film as in claim 23, wherein said 16. A multilayer film as in claim 15, wherein said 20 low-temperature sealable outer layer is pressure-sealacarbonyl-containing polymer comprises a copolyamide ble. having a melting point of less than 210° C. 26. A multilayer film as in claim 24, wherein said 17 . A multilayer film as in claim 1, wherein said inner low-temperature sealable layer comprises a natural rubbarrier layer D includes a hydroxyl group-containing ber latex= oligomer or polymer . 25 27 . A multilayer film as in claim 1, wherein said inner 18. A multilayer film as in claim 17, wherein said barrier layer D comprises at least two individual layers . inner barrier layer D includes at least one member se28 . A multilayer film as in claim 27, wherein said Iected from the group consisting of trimethylolpropy- individual layers are separated by an adhesion-promotlene, neopentyl glycol, and polyethylene glycol . ing layer therebetween. 19. A multilayer film as in claim 1, wherein the modi- 30 29. A packaged article, comprising the article to be Pied polyolefim of said adhesion-promoring layer C cornpackaged surrounded by a package comprised of the prises a graft polymer. multilayer film as defined by claim 1. 20 . A multilayer film as in claim 1, wherein said layer 30 . A multilayer film as in claim 1, wherein said layers B further comprises at least one low-molecular, miscible are coextruded at a die temperaure Q£ about 230' G
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Case 1:04-cv-01278-KAJ

Document 174-4

Filed 09/27/2005

Page 9 of 9

UNITED STATES PATENT AND TRADEMARK OFFICE

CERTIFICATE OF CORRECTION
ATENT NO . DATED INVENTOR( S)
P

4,572,854 Feb . 25, 1985 Hermann, Dallmann & Hans J . Palmen

It is certified that error appears in the above - identified patent and that said Letters Patent is hereby corrected as shown below : Title pages

[751 inventors : Her:mann Dallmann, Wiesbaden ; Hans J . Palmen, Walluf, both of Fed . Rep . of Germany [22) Filed : Feb . 22, 1984

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Signed and
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Attest:

DONALD J . QUIGG Attesting Offleer C* w+wh&fM" Of a a.d TP"dawrkr