CA1139513A - Polyvinylidene chloride and ethylene vinyl acetate film and method for making the same - Google Patents
Polyvinylidene chloride and ethylene vinyl acetate film and method for making the sameInfo
- Publication number
- CA1139513A CA1139513A CA000342679A CA342679A CA1139513A CA 1139513 A CA1139513 A CA 1139513A CA 000342679 A CA000342679 A CA 000342679A CA 342679 A CA342679 A CA 342679A CA 1139513 A CA1139513 A CA 1139513A
- Authority
- CA
- Canada
- Prior art keywords
- film
- vinyl acetate
- weight
- polyvinylidene chloride
- ethylene vinyl
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
- C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L27/04—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
- C08L27/08—Homopolymers or copolymers of vinylidene chloride
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/08—Copolymers of ethene
Abstract
POLYVINYLIDENE CHLORIDE AND
ETHYLENE VINYL ACETATE FILM
AND METHOD FOR MAKING THE SAME
ABSTRACT OF THE DISCLOSURE
A film comprises a blend of polyvinylidene chloride copolymer and an ethylene vinyl acetate copolymer having from about 5 to about 18% vinyl acetate content and a melt flow of from about 0.1 to about 1.0 decigram per minute.
S P E C I F I C A T I O N
ETHYLENE VINYL ACETATE FILM
AND METHOD FOR MAKING THE SAME
ABSTRACT OF THE DISCLOSURE
A film comprises a blend of polyvinylidene chloride copolymer and an ethylene vinyl acetate copolymer having from about 5 to about 18% vinyl acetate content and a melt flow of from about 0.1 to about 1.0 decigram per minute.
S P E C I F I C A T I O N
Description
1~2i' ~3~
The inventiorl relates to a meth3d of forming a film and the 'ilm pr3duced by the method. In addition, the invention relates to a bag fabricated from the fiLm.
Generally, p31y~ers and copolymers Df vinylidene chloride have f~und wide use as fi~ms and fi~m layers in multilayer fiLms in connection with packagi~g foodsturfs and other Db~ects. PDlyvinylidene chloride copolymer is ~nown in the art by the term "saran" and is particularly relied upon as an oxygen barrier for p-eserving foodstuffs.
One typical prior art use of a fi~m incorporating a layer of polyvinylidene chloride copolymer is for the prote~tion and storage of primal and subprimal fresh red meat cùt. One kno-wm multilaver film including polyvinylidene chloride copolymer has outer layers of ethylene vinyl acetate copDlymer and a core layer of viQylidene chl~ride copolymer and is fabricated into a bag. The bag i9 heat-shrin~able. Typically, a meat cut is placed inside the bag, the bag is evacuated and clipped closed, and then the bag is he~t-shrunk to form a strong airtight p~ckage.
Such a multilayer film is described in Canadian patent No. 982~23.
Gen~rally, it is know~ that p31y~inylidene chloride copolymer can be produced by either e~ulsion or s~spension polymerization. The suspension method as compared t~ the emulsio~ method usually prDduces a resin which is more stable and possesses a narrower particle size distribution for g~3d ~ree flow properties, and has les~
The inventiorl relates to a meth3d of forming a film and the 'ilm pr3duced by the method. In addition, the invention relates to a bag fabricated from the fiLm.
Generally, p31y~ers and copolymers Df vinylidene chloride have f~und wide use as fi~ms and fi~m layers in multilayer fiLms in connection with packagi~g foodsturfs and other Db~ects. PDlyvinylidene chloride copolymer is ~nown in the art by the term "saran" and is particularly relied upon as an oxygen barrier for p-eserving foodstuffs.
One typical prior art use of a fi~m incorporating a layer of polyvinylidene chloride copolymer is for the prote~tion and storage of primal and subprimal fresh red meat cùt. One kno-wm multilaver film including polyvinylidene chloride copolymer has outer layers of ethylene vinyl acetate copDlymer and a core layer of viQylidene chl~ride copolymer and is fabricated into a bag. The bag i9 heat-shrin~able. Typically, a meat cut is placed inside the bag, the bag is evacuated and clipped closed, and then the bag is he~t-shrunk to form a strong airtight p~ckage.
Such a multilayer film is described in Canadian patent No. 982~23.
Gen~rally, it is know~ that p31y~inylidene chloride copolymer can be produced by either e~ulsion or s~spension polymerization. The suspension method as compared t~ the emulsio~ method usually prDduces a resin which is more stable and possesses a narrower particle size distribution for g~3d ~ree flow properties, and has les~
-2-`
~3~ 2214 inheren~ cDn-aminatiOn. The resins prDduced by the suspension meth~d, h~wever, are cDstly as cD~pared to the emulsiDn resins so that fDr cD~ercial prDduction it is preferable t3 use emulsiDn resins from an ecDnomic point Df view.
Both suspension and emulsion resins present prDblems during the co~mercial pr~duction of films be-cause P~lyvinylidene chloride cDpDlvmers can be degraded by elevated temperatures. For this reason, it is a CDmmOn practice in the art tD blend pDlyvinylidene chloride copolymers with stabilizers, plasticizers, and lubricants tD improve the cD~ercial extrusiDn of polyvinylidene chlDride cDpolymers.
Generally, the extrusion Df a pDlyvinylidene chlDride copolymer pr~duced by the e~ulsiDn meth3d has the fDllowing draw~acksin cDnnection with its use in forming a film:
1) A relatively large number of black particles appear in the extrudate and the cDntinuDus appearance of these particles fre~uently breaks the biDrientation bubble.
2) A periodic slough-D~f of off-colDred extrudate ~ccurs and this results in appearance defects in the film beiLIg prDduced as well as breaks in the bioriellt2tion bubble.
~ 3 12214
~3~ 2214 inheren~ cDn-aminatiOn. The resins prDduced by the suspension meth~d, h~wever, are cDstly as cD~pared to the emulsiDn resins so that fDr cD~ercial prDduction it is preferable t3 use emulsiDn resins from an ecDnomic point Df view.
Both suspension and emulsion resins present prDblems during the co~mercial pr~duction of films be-cause P~lyvinylidene chloride cDpDlvmers can be degraded by elevated temperatures. For this reason, it is a CDmmOn practice in the art tD blend pDlyvinylidene chloride copolymers with stabilizers, plasticizers, and lubricants tD improve the cD~ercial extrusiDn of polyvinylidene chlDride cDpolymers.
Generally, the extrusion Df a pDlyvinylidene chlDride copolymer pr~duced by the e~ulsiDn meth3d has the fDllowing draw~acksin cDnnection with its use in forming a film:
1) A relatively large number of black particles appear in the extrudate and the cDntinuDus appearance of these particles fre~uently breaks the biDrientation bubble.
2) A periodic slough-D~f of off-colDred extrudate ~ccurs and this results in appearance defects in the film beiLIg prDduced as well as breaks in the bioriellt2tion bubble.
~ 3 12214
3) The resin flow in the h~pper f~r the extrusion screw is uneven.
4) Non-cyclic pressure puLsations ~ccur in the extruder and these cause pulsal~iDns in the DUtpUt rate and unstable conditiDns along the extruder screw.
~ ne instant invention D~ercDmes these prDblems and teaches the step ~f mixing, for example, pDlyvinylidene ch~oride cDp~lymer pr~duced by the emulsiDn method with apprDpriate stabilizers, plasticizers, and lubricant al3ng with a selected ethylene vinyl acetate copDlymer.
~hen this mixture is extruded~ for example, as a core layer Df a multilayer film having outer layers Df ethylene vinyl acetate copolymers, the follDwing surprising results occur.
(1) The number Df black particles în the extrudate is decreased alDng with the number Df biorientatiDn bubble breaks.
(2) The extruder head pressure fluctuatio~s are reduced Dr eliminated and this indicates a more stable ~0 melt conditiDn.
(3) A greater Dutput per extruder screw revDlutiDn ratio occurs.
(4) Most ~ilm prDperties dD nDt show a substantial change as cDmpared tD a multilayer film having a core layer with~ut the added ethylene vinyl acetate cDpolvmer~
~.~3~3
~ ne instant invention D~ercDmes these prDblems and teaches the step ~f mixing, for example, pDlyvinylidene ch~oride cDp~lymer pr~duced by the emulsiDn method with apprDpriate stabilizers, plasticizers, and lubricant al3ng with a selected ethylene vinyl acetate copDlymer.
~hen this mixture is extruded~ for example, as a core layer Df a multilayer film having outer layers Df ethylene vinyl acetate copolymers, the follDwing surprising results occur.
(1) The number Df black particles în the extrudate is decreased alDng with the number Df biorientatiDn bubble breaks.
(2) The extruder head pressure fluctuatio~s are reduced Dr eliminated and this indicates a more stable ~0 melt conditiDn.
(3) A greater Dutput per extruder screw revDlutiDn ratio occurs.
(4) Most ~ilm prDperties dD nDt show a substantial change as cDmpared tD a multilayer film having a core layer with~ut the added ethylene vinyl acetate cDpolvmer~
~.~3~3
(5) The oxygen permeability rate of the multilayer film remains almost: unchanged or increases slightly.
(6) The adhesion bet:ween the film layers is improved.
The invention can be used in connection with polyvinylidene chloride copolymer produced by the emulsion or suspension method as well as combinations of the emulsion and suspension resins.
One embodiment of the instant invention is a film comprising from about 60% to about 95% by weight of a polyvinylidene chloride copolymer and from about 5~ to about 40-~ by weight of an ethylene vinyl acetate copolymer containing from about 5% to about 18%
by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigrams per minute. Preferably, the ethylene vinyl acetate copolymer contains from about 5% to about 15% by weight vinyl acetate to provide a more acceptable o~ygen transmission barrier and for economical production.
Another embodiment of the invention is the aforementioned film wherein the polyvinylidene chloride ~21~
~3~ 3 copGlymer is ~rom about 80% to about 95~ by weight and the ethy]ene uinyl acetate cDpDlymer is frDm about 5~l~ to about 20% by weight and cDn~ains frD2 about 5% tD about 15% by weight vinyl acetate so that the total oxygen trans-mission at room temperature of the film is le5s than about 3 cubic centimeter per 100 square inches-24 hours-atmosphexe.
A further embodiment of the invention is the aLDrementioned film wherein the pDlyvinylidene chloride cDpolymer is about 90% by weight and the ethylene vinyl aceta~e cop~lymer is about 10% by weight and contains from about 5% to about 18% by weight vinyl acetate so that the total oxygen transmission at room temperature of the film is about 2.3 CU~DiC centimeter per 100 s~uare inches-24-hours-atmosphere. This e~bDd~ment is particularly suited for film production using ethylene vinyl acetate copolymers which ~ay have variable amounts of vinyl acetate cDntent.
Yet a further embDdiment Df the invention is the afDrementiDned film wherein the ~thylene vinyl acetate copolymer cDntains about 12% vinyl acetate so that the total oxygen transmissi~n at r~om temperature is about 2.4 cubic centimeter per 100 square inches- ~
24 hDurs-atmosphere. This embodiment is particularly suited for film prDduction in which the amount of the ethylene vinvl acetate cDpolymer being used need not be cDntrolled precisely.
Still ~ further embDdiment Df the invention is ame~hod of producing a heat shl}nkable fit~ cDm2rising the steps Df mixing tDgether fr~m about 60~, to about 95% by weight a polyvinylidene chloride copDlymer and fr~m abDut 5% to about 40% by weight of an ethylene vinyl acetate copolymer cDntaining frDm about 5% tD about 18V/G by weight vinyl acetate and having a melt fl3w of from about 0.1 to about 1.0 decigrams per minute, extruding the mlxture, and biaxially Drienting the extrudate.
Preferably, the film of the invention is a heat shrinXable multilayer film cDmprising outer layers of ethylene vinyl acetate cDntaining from about 10% to about 1S% by wei~ht vinyl acetate and having a ~elt ~l~w of Irom about 0.1 to about 1.0 decigram per minute and a core layer comprising from about 60% to about 95% by weight of a polyvinylidene chloride copoiymer and from 5% to about 40% by weight of an ethylene vinyl acetate copolymer containing from about 5% tD about 18% by weight of vinyl acetate and having a melt flow Df from about 0.1 tD about 1.0 decigrams per minute, ~referably,the aforementioned multilayer film consists essentially of the three layers The inventiDn acc~rdingly comprises the several steps and relation of cne Dr more of such steps with respect tD each Df.the others, all as exempliried in the foll~wing detailed disclDsure, and the scope of the applicatiDn of wnich will be indicated in the cla7ms.
Generally, the three layer film of the instant invention has an overall thickness of from about 2 to 3 mils and preferably about 2.4 mils. The biaxial orientation can be carried out in accordance with ~nown methods such as the method described in the U. S~ Patent No. 3,555,60~ to Pahlke. This patent discloses a process in which a polyethylene material defines an isolated bubble maintained by simple nip rollers and the bubble is subjected to heat and radial expansion due to internal pressure near the draw point of the tubing, that is, the point at which the polyethylene material is at or just below its softening point. This process is generally referred to as the "double bubble" method.
Generally, the polyvinylidene chloride copolymer used in the invention comprises at least about 65% by weight polymerized vinylidene chloride and the balance is a polymer of vinyl chloride, acrylonitrile, an acrylate ester such as methyl methacrylate, ox the like.
The film of the invention is preferably biaxially oriented, but it can also be a slot cast film or a blown film prepared by conventional methods.
In accordance with conventional practice, it is understood that additives such as stabilizers, plasticizers, and lubricants can be used for producing the film of the invention ancl it is understood in the specification and the claims that such additives can be present in accord-ance with conventional practice.
Illustrative non-limiting examples of the practice of the invention are set out below. Numerous ~ 3 12214 other examples can easily be evolved in the light of the guiding principles and teachings contained herein.
The examples given herein are intended mainly tD
illus,rate the inventiDn and nDt in any sense tD limit the ~nner in which the inventiDn can be practiced, All percentages and parts stated herein are by weight unless Dtherwise stated.
As used herein, the term l'phr" has the conventional meaning of parts per 100 parts of polymer.
The materials described herein have their properties determined in accordance with the following test methods:
Melt F1DW - ASTM D -1238 Ethylene vinyl acetate copolymer - C~ndition E
PDlybutylene - CDndition E
PDlypropylene-ethylene copolymer - CDndition L
Density ASTM B-1505 The following polymers shown in Table 1 are used in the examples:
~3~q~ 11214 Table 1 Melt Flow Density Polymer dg /min . ~m/ c c - Descrip t ion EVA A 0.3 Ethylene vinyl acetate copolymer; 12% by wt.
vinyl acetate.
EVA B 0.7 Ethylene vinyl acetate copolymer; 18% by wt.
vinyl acetate.
EVA C 0.5 Ethylene vinyl acetate copolymer; 15% by wt.
vinyl acetate.
EVA D 1.0 Ethylene vinyl acetate copolymer; 12% by wt.
vinyl acetate.
EVA E 0.6 Ethylene vinyl acetate copolymer, 9~/O by wt.
vinyl acetate.
EVA F 0.3 Ethylene vinyl acetate copolymer; 5% by wt.
vinyl acetate.
P-E A 12.0 0.899 Polypropylene-ethylene copolymer; typically sold commerci~lly as PP9818 by Diamond Shamrock.
P-B A 2.0 0.91 Polybutylene copolymer;
typically sold commercially as Witron~ 1200 by Witco Chemical Co.
Elastomer A Ethylene-polypropylene copolymer elastomer; typically sold commercially as Vistalon~7 702 by Exxon Chemical Co.
3 1221~
The following polyvinylidene chloride polymers shown in table 2 are used in the examples:
Table 2 Polyvinylidene Chloride Type and Commercial Designatlon by Dow Chemical Company PVDC A Emulsion type, Dow~ 5236.13 PVDC B Emulsion type, Dow~ 925 PVDC C Suspension type; Dow~ 468 PVDC D Suspension type available from Kureha Chemical Co.
The following blends of polyvinylidene chloride copolymers shown in table 3 are used in the examples:
Table 3 Blend 1 100 phr PVDC A
6.75 phr stabilizer, plasticizer, and lubricant Blend 2 100 phr PVDC A
5.0 phr stabilizer, plasticizer, and lubricant Blend 3 100 phr PVDC A
3.0 phr stabilizer and lubricant Blend 4 100 phr PVDC B
6.75 phr stabilizer, plasticizer, and lubricant . . .
~39~3 12214 Table 3 (cDntinued) Blend 5 .
100 phr PVDC B
5.75 phr stabilizer, plasticizer, and lubricant Blend 6 100 phr PVDC B
6.5 phr stabilizer, plasticizer~ and lubricant Blend 7 90 phr PVDC A
10 phr PVDC C
6.75 phr stabilizer, plasticizer, and lubricant Blend 8 90 phr PV~C B
10 phr PVDC D
6.5 phr stabilizer, plasticizer, and lubricant ' .
~ 't~ 3 ~2~14 Examples 1 to 17 Examples 1 to 17 were carri~d out using an emulsion type polyvinylidene chloride copoly~er in a core layer of a three layer fiLm.
The multilayer film consisted essentially of outer layers of ethylene vinyl acetate copolvmer and a core layer as shown in tzble 4.
The multilayer film was produced by convention~l metnods in accordance with the "double bubble" process such ~s described in the U. S. patent no. 3,555,604 to PahlhebY coextrusion of layers through a multilayer tubular die. Reference is also had to the Canadian patent no.
982,923 which teaches a multilayer fiL~ including outer layers of ethylene vinyl acetate and a core layer of vinylidene chloride copolymer.
For the examples 4 to 12, and 17, the thicknesses of the layers were not measured. The layers were controlled to maintain thicknesses about the same as the corresponding layers of the examples 1 to 3, 15 and 16.
Table 4 First Outer Second Outer Core Layer Layer - EVA C Layer - EVA A PVDC Blend EYA
Ex. % Thickness% Thickness % %
1 23.1 58.5 Blend 1 EVA C
95.0 5.0 2 24.3 54.5 Blend 2 EVA B
94.0 6.0 3 24.5 57.1 Blend 3 EVA B
90.0 10.0 4 Blend 4 EVA A
94.0 6.0 Blend 4 EVA A
90.0 10.0 6 31end 4 EVA A
85.0 15.0
The invention can be used in connection with polyvinylidene chloride copolymer produced by the emulsion or suspension method as well as combinations of the emulsion and suspension resins.
One embodiment of the instant invention is a film comprising from about 60% to about 95% by weight of a polyvinylidene chloride copolymer and from about 5~ to about 40-~ by weight of an ethylene vinyl acetate copolymer containing from about 5% to about 18%
by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigrams per minute. Preferably, the ethylene vinyl acetate copolymer contains from about 5% to about 15% by weight vinyl acetate to provide a more acceptable o~ygen transmission barrier and for economical production.
Another embodiment of the invention is the aforementioned film wherein the polyvinylidene chloride ~21~
~3~ 3 copGlymer is ~rom about 80% to about 95~ by weight and the ethy]ene uinyl acetate cDpDlymer is frDm about 5~l~ to about 20% by weight and cDn~ains frD2 about 5% tD about 15% by weight vinyl acetate so that the total oxygen trans-mission at room temperature of the film is le5s than about 3 cubic centimeter per 100 square inches-24 hours-atmosphexe.
A further embodiment of the invention is the aLDrementioned film wherein the pDlyvinylidene chloride cDpolymer is about 90% by weight and the ethylene vinyl aceta~e cop~lymer is about 10% by weight and contains from about 5% to about 18% by weight vinyl acetate so that the total oxygen transmission at room temperature of the film is about 2.3 CU~DiC centimeter per 100 s~uare inches-24-hours-atmosphere. This e~bDd~ment is particularly suited for film production using ethylene vinyl acetate copolymers which ~ay have variable amounts of vinyl acetate cDntent.
Yet a further embDdiment Df the invention is the afDrementiDned film wherein the ~thylene vinyl acetate copolymer cDntains about 12% vinyl acetate so that the total oxygen transmissi~n at r~om temperature is about 2.4 cubic centimeter per 100 square inches- ~
24 hDurs-atmosphere. This embodiment is particularly suited for film prDduction in which the amount of the ethylene vinvl acetate cDpolymer being used need not be cDntrolled precisely.
Still ~ further embDdiment Df the invention is ame~hod of producing a heat shl}nkable fit~ cDm2rising the steps Df mixing tDgether fr~m about 60~, to about 95% by weight a polyvinylidene chloride copDlymer and fr~m abDut 5% to about 40% by weight of an ethylene vinyl acetate copolymer cDntaining frDm about 5% tD about 18V/G by weight vinyl acetate and having a melt fl3w of from about 0.1 to about 1.0 decigrams per minute, extruding the mlxture, and biaxially Drienting the extrudate.
Preferably, the film of the invention is a heat shrinXable multilayer film cDmprising outer layers of ethylene vinyl acetate cDntaining from about 10% to about 1S% by wei~ht vinyl acetate and having a ~elt ~l~w of Irom about 0.1 to about 1.0 decigram per minute and a core layer comprising from about 60% to about 95% by weight of a polyvinylidene chloride copoiymer and from 5% to about 40% by weight of an ethylene vinyl acetate copolymer containing from about 5% tD about 18% by weight of vinyl acetate and having a melt flow Df from about 0.1 tD about 1.0 decigrams per minute, ~referably,the aforementioned multilayer film consists essentially of the three layers The inventiDn acc~rdingly comprises the several steps and relation of cne Dr more of such steps with respect tD each Df.the others, all as exempliried in the foll~wing detailed disclDsure, and the scope of the applicatiDn of wnich will be indicated in the cla7ms.
Generally, the three layer film of the instant invention has an overall thickness of from about 2 to 3 mils and preferably about 2.4 mils. The biaxial orientation can be carried out in accordance with ~nown methods such as the method described in the U. S~ Patent No. 3,555,60~ to Pahlke. This patent discloses a process in which a polyethylene material defines an isolated bubble maintained by simple nip rollers and the bubble is subjected to heat and radial expansion due to internal pressure near the draw point of the tubing, that is, the point at which the polyethylene material is at or just below its softening point. This process is generally referred to as the "double bubble" method.
Generally, the polyvinylidene chloride copolymer used in the invention comprises at least about 65% by weight polymerized vinylidene chloride and the balance is a polymer of vinyl chloride, acrylonitrile, an acrylate ester such as methyl methacrylate, ox the like.
The film of the invention is preferably biaxially oriented, but it can also be a slot cast film or a blown film prepared by conventional methods.
In accordance with conventional practice, it is understood that additives such as stabilizers, plasticizers, and lubricants can be used for producing the film of the invention ancl it is understood in the specification and the claims that such additives can be present in accord-ance with conventional practice.
Illustrative non-limiting examples of the practice of the invention are set out below. Numerous ~ 3 12214 other examples can easily be evolved in the light of the guiding principles and teachings contained herein.
The examples given herein are intended mainly tD
illus,rate the inventiDn and nDt in any sense tD limit the ~nner in which the inventiDn can be practiced, All percentages and parts stated herein are by weight unless Dtherwise stated.
As used herein, the term l'phr" has the conventional meaning of parts per 100 parts of polymer.
The materials described herein have their properties determined in accordance with the following test methods:
Melt F1DW - ASTM D -1238 Ethylene vinyl acetate copolymer - C~ndition E
PDlybutylene - CDndition E
PDlypropylene-ethylene copolymer - CDndition L
Density ASTM B-1505 The following polymers shown in Table 1 are used in the examples:
~3~q~ 11214 Table 1 Melt Flow Density Polymer dg /min . ~m/ c c - Descrip t ion EVA A 0.3 Ethylene vinyl acetate copolymer; 12% by wt.
vinyl acetate.
EVA B 0.7 Ethylene vinyl acetate copolymer; 18% by wt.
vinyl acetate.
EVA C 0.5 Ethylene vinyl acetate copolymer; 15% by wt.
vinyl acetate.
EVA D 1.0 Ethylene vinyl acetate copolymer; 12% by wt.
vinyl acetate.
EVA E 0.6 Ethylene vinyl acetate copolymer, 9~/O by wt.
vinyl acetate.
EVA F 0.3 Ethylene vinyl acetate copolymer; 5% by wt.
vinyl acetate.
P-E A 12.0 0.899 Polypropylene-ethylene copolymer; typically sold commerci~lly as PP9818 by Diamond Shamrock.
P-B A 2.0 0.91 Polybutylene copolymer;
typically sold commercially as Witron~ 1200 by Witco Chemical Co.
Elastomer A Ethylene-polypropylene copolymer elastomer; typically sold commercially as Vistalon~7 702 by Exxon Chemical Co.
3 1221~
The following polyvinylidene chloride polymers shown in table 2 are used in the examples:
Table 2 Polyvinylidene Chloride Type and Commercial Designatlon by Dow Chemical Company PVDC A Emulsion type, Dow~ 5236.13 PVDC B Emulsion type, Dow~ 925 PVDC C Suspension type; Dow~ 468 PVDC D Suspension type available from Kureha Chemical Co.
The following blends of polyvinylidene chloride copolymers shown in table 3 are used in the examples:
Table 3 Blend 1 100 phr PVDC A
6.75 phr stabilizer, plasticizer, and lubricant Blend 2 100 phr PVDC A
5.0 phr stabilizer, plasticizer, and lubricant Blend 3 100 phr PVDC A
3.0 phr stabilizer and lubricant Blend 4 100 phr PVDC B
6.75 phr stabilizer, plasticizer, and lubricant . . .
~39~3 12214 Table 3 (cDntinued) Blend 5 .
100 phr PVDC B
5.75 phr stabilizer, plasticizer, and lubricant Blend 6 100 phr PVDC B
6.5 phr stabilizer, plasticizer~ and lubricant Blend 7 90 phr PVDC A
10 phr PVDC C
6.75 phr stabilizer, plasticizer, and lubricant Blend 8 90 phr PV~C B
10 phr PVDC D
6.5 phr stabilizer, plasticizer, and lubricant ' .
~ 't~ 3 ~2~14 Examples 1 to 17 Examples 1 to 17 were carri~d out using an emulsion type polyvinylidene chloride copoly~er in a core layer of a three layer fiLm.
The multilayer film consisted essentially of outer layers of ethylene vinyl acetate copolvmer and a core layer as shown in tzble 4.
The multilayer film was produced by convention~l metnods in accordance with the "double bubble" process such ~s described in the U. S. patent no. 3,555,604 to PahlhebY coextrusion of layers through a multilayer tubular die. Reference is also had to the Canadian patent no.
982,923 which teaches a multilayer fiL~ including outer layers of ethylene vinyl acetate and a core layer of vinylidene chloride copolymer.
For the examples 4 to 12, and 17, the thicknesses of the layers were not measured. The layers were controlled to maintain thicknesses about the same as the corresponding layers of the examples 1 to 3, 15 and 16.
Table 4 First Outer Second Outer Core Layer Layer - EVA C Layer - EVA A PVDC Blend EYA
Ex. % Thickness% Thickness % %
1 23.1 58.5 Blend 1 EVA C
95.0 5.0 2 24.3 54.5 Blend 2 EVA B
94.0 6.0 3 24.5 57.1 Blend 3 EVA B
90.0 10.0 4 Blend 4 EVA A
94.0 6.0 Blend 4 EVA A
90.0 10.0 6 31end 4 EVA A
85.0 15.0
7 . Blend 4 EVA A
80.0 20.0
80.0 20.0
8 Blend 4 100 . O --
9 Blend 5 EVA A
94.0 6.0 Blend 5 EVA A
90-0 10.~
11 Blend 5 EVA A
85.0 15.0 12 Blend 5 EVA A
80.0 20.0 13 25.0 4.0 Blend 6 -- -100.O
14 24.6 55.0 Blend 6 EVA A
90, O 10 . O
5~3 Table 4 (c~ntinued) First Outer SecDnd Outer Core Laver Layer - EVA C L2yer - EVA A P~3C Blend EV~
Ex. ~/~ Thickness ~c Thickness % . %
__ _ 24.1 54.6 Blend 6 EVA A
65.0 35.0 16 25.4 53.3 Blend 6 EVA A
50.0 50.0 17 Blend 6 EVA A
40.0 60.0 EVA = ethylene vinyl acetate copolymer TDtal film thickness is about 2.5 mils.
Example 18 to 37 Examples 18 tD 37 were carried out by the same method as the examples 1 tD 17 and used a blend of em~lsion and suspension types of p~lyvinylidene chloride p~lymer. Table 5 shows the examples 18 tD 37.
The thicknesses Df the layers Df the examples 33 tD
37 were ccntr311ed tD be about the same as the correspDnding layers Df the examples 18 to 32.
Examples 38 and 39 E~amples 38 and 39 were carried out by the same method as the ex~mples 1 tD 17 except that the example 39 had four layers. Table 6 shows the examples 38 and 39. For the example 38, the first outer layer was EVA C
and for the example 39 the first outer layer was a blend of 40~ by weight of P-E A, 40% by weight of P-B A and 20~ by weight of Elastomer A.
122~!, ~3~
Table ~
First Outer SecDnd Outer CDre Layer Layer - EVA C ~ayer - EVA A F~DC Blend EVA
Ex. % Thickness ~/c Thickness_ _ % v/
18 25.5 57.9 Blend 7 EVA B
g5 5 19 24.2 54.9 Blend 8 EVA B
24.2 54.9 Blend 8 EVA C
21 24.2 54.9 Blend 8 EVA A
22 24.6 55.3 Blend 8 --23 23.8 54.6 Blend 8 EVA B
24 23.8 54.6 31end 8 EVA B
23.8 54.6 Blend 8 EVA C
26 23.9 54.6 Blend 8 EV~oC
27 24.0 55.1 92 EVA8 A
28 25.1 54.1 90 .10 29 25.1 54.1 88 EVA2A
23.7 54.6 85 E~A15A
31 23.7 54.6 Blend 8 ~V2AoA
L__14 3 ~
Table5 (cDntinued) First C~ter SecDnd ~uter _ C _e_~yer _ ~ayer - EVA C laver - E~rA ,~ PVDC Blend E~A
Ex. % ~hickness ~/= Thickrless % %
32 23.4 55.0 Blend 8 EVA C
33 . Blend 8 EVA A
34 Blend 8 EVA A
Blend 8 EVA D
36 Blend 8 EVA E
37 Blend 8 EVA F
go 10 EVA = ethylene vinyl acetace c~p~lymer TDtal film thickness is ab~ut 2.5 mils.
q~
Table 6 .; Second First First Outer Layer CDre L~yer Second Core Layer Outer Layer EVA A EVA P~DC Blend EVA
Ex. 7 Thickness ~/~ Thickness ~/O Thickness % %
O _ _ - 38 25.254.2 -- Blend 7 E~A B
39 23.941.5E~A C Blend 7 EVA B
11.~ 95 5 . . : . .
EVA = ethylene vinyl acetate cop~lymer TDtal film thickness is abDut 3 mils.
Test Results The films of the tnree sets Df examples, that is, examples 1 to 17, 18 tD 37, 38 and 39 were tested for variDus pr~perties and the results ~f these tests are given in the tables 7, 8, 9. For sDme ex~mples, s~me of the parameters were nDt measured and conse~uently, are not shown.
Several bags were formed by conventi3nal methods from various films and Dund to be satisfactDry.
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x The examples surprisingly show that blends of the polyvinylidene chloride copolymer and ethylene vinyl acetate copolymer of the invention provide acceptable levels of permeability for use in connection with the storage of food stuff.
Typically, a three layer film including a core layer of a blend of the invention having from about 5% to about 20% by weight ethylene vinyl acetate copolymer con-taining from about 5% to about 15% by weight vinyl acetate has total oxygen permeability at room temperature of less than about 3 cubic centimeter per 100 square inches-24 hours-atmosphere.
A three layer film including a core layer of a blend of the invention having about 10% by weight ethylene vinyl acetate copolymer containing from about 5% to about 18~ by weight vinyl acetate exhibits a total oxygen permeability at room temperature of about 2.3 cubic centimeter per 100 square inches-24 hours-atmosphere.
A three layer film including a core layer of a blend of the invention having from about 5% to about 40%
by weight ethylene vinyl acetate copolymer containing about 12% by weight vinyl acetate exhibits a total oxygen permeability at room temperature of about 2.4 cubic centimeter per 100 square inches 24-hours-atmosphere.
~39~3 12214 T~e oxygen permeability ~f the multilayered films is determined by the pDlyvinylidene chloride copoly~er and etkylene vinyl acetate copoly~er layer.
We wish it tD be understood that we do nDt desire to be limited to the exact details ~f construction shown and described, fo. DbviDus m3difications will occur to a person skilled in the art.
Having tnus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:
94.0 6.0 Blend 5 EVA A
90-0 10.~
11 Blend 5 EVA A
85.0 15.0 12 Blend 5 EVA A
80.0 20.0 13 25.0 4.0 Blend 6 -- -100.O
14 24.6 55.0 Blend 6 EVA A
90, O 10 . O
5~3 Table 4 (c~ntinued) First Outer SecDnd Outer Core Laver Layer - EVA C L2yer - EVA A P~3C Blend EV~
Ex. ~/~ Thickness ~c Thickness % . %
__ _ 24.1 54.6 Blend 6 EVA A
65.0 35.0 16 25.4 53.3 Blend 6 EVA A
50.0 50.0 17 Blend 6 EVA A
40.0 60.0 EVA = ethylene vinyl acetate copolymer TDtal film thickness is about 2.5 mils.
Example 18 to 37 Examples 18 tD 37 were carried out by the same method as the examples 1 tD 17 and used a blend of em~lsion and suspension types of p~lyvinylidene chloride p~lymer. Table 5 shows the examples 18 tD 37.
The thicknesses Df the layers Df the examples 33 tD
37 were ccntr311ed tD be about the same as the correspDnding layers Df the examples 18 to 32.
Examples 38 and 39 E~amples 38 and 39 were carried out by the same method as the ex~mples 1 tD 17 except that the example 39 had four layers. Table 6 shows the examples 38 and 39. For the example 38, the first outer layer was EVA C
and for the example 39 the first outer layer was a blend of 40~ by weight of P-E A, 40% by weight of P-B A and 20~ by weight of Elastomer A.
122~!, ~3~
Table ~
First Outer SecDnd Outer CDre Layer Layer - EVA C ~ayer - EVA A F~DC Blend EVA
Ex. % Thickness ~/c Thickness_ _ % v/
18 25.5 57.9 Blend 7 EVA B
g5 5 19 24.2 54.9 Blend 8 EVA B
24.2 54.9 Blend 8 EVA C
21 24.2 54.9 Blend 8 EVA A
22 24.6 55.3 Blend 8 --23 23.8 54.6 Blend 8 EVA B
24 23.8 54.6 31end 8 EVA B
23.8 54.6 Blend 8 EVA C
26 23.9 54.6 Blend 8 EV~oC
27 24.0 55.1 92 EVA8 A
28 25.1 54.1 90 .10 29 25.1 54.1 88 EVA2A
23.7 54.6 85 E~A15A
31 23.7 54.6 Blend 8 ~V2AoA
L__14 3 ~
Table5 (cDntinued) First C~ter SecDnd ~uter _ C _e_~yer _ ~ayer - EVA C laver - E~rA ,~ PVDC Blend E~A
Ex. % ~hickness ~/= Thickrless % %
32 23.4 55.0 Blend 8 EVA C
33 . Blend 8 EVA A
34 Blend 8 EVA A
Blend 8 EVA D
36 Blend 8 EVA E
37 Blend 8 EVA F
go 10 EVA = ethylene vinyl acetace c~p~lymer TDtal film thickness is ab~ut 2.5 mils.
q~
Table 6 .; Second First First Outer Layer CDre L~yer Second Core Layer Outer Layer EVA A EVA P~DC Blend EVA
Ex. 7 Thickness ~/~ Thickness ~/O Thickness % %
O _ _ - 38 25.254.2 -- Blend 7 E~A B
39 23.941.5E~A C Blend 7 EVA B
11.~ 95 5 . . : . .
EVA = ethylene vinyl acetate cop~lymer TDtal film thickness is abDut 3 mils.
Test Results The films of the tnree sets Df examples, that is, examples 1 to 17, 18 tD 37, 38 and 39 were tested for variDus pr~perties and the results ~f these tests are given in the tables 7, 8, 9. For sDme ex~mples, s~me of the parameters were nDt measured and conse~uently, are not shown.
Several bags were formed by conventi3nal methods from various films and Dund to be satisfactDry.
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x The examples surprisingly show that blends of the polyvinylidene chloride copolymer and ethylene vinyl acetate copolymer of the invention provide acceptable levels of permeability for use in connection with the storage of food stuff.
Typically, a three layer film including a core layer of a blend of the invention having from about 5% to about 20% by weight ethylene vinyl acetate copolymer con-taining from about 5% to about 15% by weight vinyl acetate has total oxygen permeability at room temperature of less than about 3 cubic centimeter per 100 square inches-24 hours-atmosphere.
A three layer film including a core layer of a blend of the invention having about 10% by weight ethylene vinyl acetate copolymer containing from about 5% to about 18~ by weight vinyl acetate exhibits a total oxygen permeability at room temperature of about 2.3 cubic centimeter per 100 square inches-24 hours-atmosphere.
A three layer film including a core layer of a blend of the invention having from about 5% to about 40%
by weight ethylene vinyl acetate copolymer containing about 12% by weight vinyl acetate exhibits a total oxygen permeability at room temperature of about 2.4 cubic centimeter per 100 square inches 24-hours-atmosphere.
~39~3 12214 T~e oxygen permeability ~f the multilayered films is determined by the pDlyvinylidene chloride copoly~er and etkylene vinyl acetate copoly~er layer.
We wish it tD be understood that we do nDt desire to be limited to the exact details ~f construction shown and described, fo. DbviDus m3difications will occur to a person skilled in the art.
Having tnus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:
Claims (30)
1. A film comprising from about 60% to about 95%
by weight of a polyvinylidene chloride copolymer and from about 5% to about 40% by weight of an ethylene vinyl acetate copolymer containing from about 5% to about 18%
by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigram per minute.
by weight of a polyvinylidene chloride copolymer and from about 5% to about 40% by weight of an ethylene vinyl acetate copolymer containing from about 5% to about 18%
by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigram per minute.
2. The film of claim 1, wherein said ethylene vinyl acetate copolymer contains from about 5% to about 15% by weight vinyl acetate.
3. The film of claim 1, wherein said polyvinylidene chloride copolymer is from about 80% to about 95% by weight and said ethylene vinyl acetate copolymer is from 5% to about 20% by weight and contains from about 5% to about 15% by weight vinyl acetate.
4. The film of claim 1, wherein said polyvinylidene chloride copolymer is about 90% by weight and said ethylene vinyl acetate copolymer is about 10% by weight.
5. The film of claim 1, wherein said polyvinylidene chloride copolymer is from about 60% to about 95% by weight and said ethylene vinyl acetate copolymer contains about 12% by weight vinyl acetate.
6. The film of claim 1, wherein said film is a multilayer film having coextruded layers.
7. The film of claim 6, comprising outer layers of ethylene vinyl acetate copolymer containing from about 10%
to about 15% by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigram per minute.
to about 15% by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigram per minute.
8. The film of claim 7, comprising said outer layers and a core layer comprising from about 60% to about 95% by weight of 2 polyvinylidene chloride copolymer and from about 5% to about 40% by weight of an ethylene vinyl acetate copolymer containing from about 5% to about 18% by weight of vinyl acetate and having a melt flow of from about 0.1 to about 1. 0 decigrams per minute.
9. The film of claim 7, wherein the overall thickness is from about 2 to about 3 mils.
10. The film of claim l, wherein said polyvinylidene chloride copolymer is an emulsion type.
11. The film of claim 1, wherein said polyvinylidene chloride copolymer is a suspension type.
12. The film of claim 1, wherein said polyvinylidene chloride copolymer is a blend of emulsion and suspension types.
13. A method of producing a film comprising the steps of mixing together from about 60% to about 95% by weight of a polyvinylidene chloride copolymer and from about 5% to about 40% by weight of an ethylene vinyl acetate copolvmer containing from about 5% to about 18% by weight vinyl acetate and having a melt flow of from about 0.1 to about 1.0 decigram per minute; and extruding the mixture to form said film.
14. The method of claim 13, wherein said ethylene vinyl acetate copolymer contains from about 5% to about 15% by weight vinyl acetate.
15. The method of claim 13, wherein said polyvinylidene chloride copolymer is from about 80%
to about 95% by weight and said ethylene vinyl acetate copolymer is from 5% to about 20% by weight and contains from about 5% to about 15% by weight vinyl acetate.
to about 95% by weight and said ethylene vinyl acetate copolymer is from 5% to about 20% by weight and contains from about 5% to about 15% by weight vinyl acetate.
16. The method of claim 13, wherein said polyvinylidene chloride copolymer is about 90% by weight and said ethylene vinyl acetate copolymer is about 10% by weight.
17. The method of claim 13, wherein said polyvinylidene chloride copolymer is from about 60% to about 95% by weight and said ethylene vinyl acetate co-polymer contains about 12% by weight vinyl acetate.
18. The method of claim 13, wherein said film is a multilayer film and the layers of said film are coextruded.
19. The method of claim 18, wherein the outer layers of said film are ethylene vinyl acetate copolymer containing from about 10% to about 15% by weight vinyl acetate and having a melt flow of from about 0.1 to about l.0 decigram per minute.
20. The method of claim 19, wherein said film includes a core layer comprising from about 60% to about 95% by weight of a polyvinylidene chloride copolymer and from about 5% to about 40% by weight of an ethylene vinyl acetate copolymer containing from about 5% to about 18%, by weight of vinyl acetate and having a melt flow of from about 0,1 to about l.0 decigrams per minute.
21. The method of claim 19, wherein the overall thickness is from about 2 to about 3 mils.
22. The method of claim 13, wherein said polyvinylidene chloride copolymer is an emulsion type.
23. The method of claim 13, wherein said polyvinylidene chloride copolymer is a suspension type.
24. The method of claim 13, wherein said polyvinylidene chloride copolymer is a blend of emulsion and suspension types.
25. The film of claim 1, wherein said film is biaxially oriented.
26. The film of claim 1, wherein said film is a slot cast film.
27. The film of claim 1, wherein said film is a blown film.
28. The method of claim 13, further comprising the step of biaxially orienting said film.
29. The method of claim 13, wherein said film is formed by the slot cast method.
30. The method of claim 13, further comprising the step of forming a blown film.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US67379A | 1979-01-03 | 1979-01-03 | |
| US000,673 | 1979-01-03 |
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| Publication Number | Publication Date |
|---|---|
| CA1139513A true CA1139513A (en) | 1983-01-18 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000342679A Expired CA1139513A (en) | 1979-01-03 | 1979-12-27 | Polyvinylidene chloride and ethylene vinyl acetate film and method for making the same |
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| Country | Link |
|---|---|
| JP (1) | JPS55108442A (en) |
| AR (1) | AR218188A1 (en) |
| AU (1) | AU535896B2 (en) |
| BR (1) | BR8000002A (en) |
| CA (1) | CA1139513A (en) |
| DE (1) | DE2952653C2 (en) |
| DK (1) | DK2080A (en) |
| FR (1) | FR2445845A1 (en) |
| GB (1) | GB2038861B (en) |
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| US4362834A (en) * | 1979-12-26 | 1982-12-07 | The Dow Chemical Company | Extrusion-grade vinylidene chloride copolymer compositions and films prepared therefrom |
| US4360489A (en) | 1981-02-02 | 1982-11-23 | The Dow Chemical Company | Process for adding magnesium oxide to film forming vinylidene chloride copolymer compositions |
| AU584276B2 (en) * | 1986-02-27 | 1989-05-18 | Dow Chemical Company, The | Blends of vinylidene chloride copolymers and olefin copolymers and films produced therefrom |
| WO1996034050A1 (en) * | 1995-04-27 | 1996-10-31 | Kureha Chemical Industry Co., Ltd. | Vinylidene chloride copolymer resin composition, film produced therefrom, extrusion process for the composition, and process for producing the film |
| JP6999384B2 (en) * | 2017-11-30 | 2022-01-18 | 株式会社クレハ | Vinylidene chloride-based resin film, packed packaging using it, and its manufacturing method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4112181A (en) * | 1961-12-05 | 1978-09-05 | W. R. Grace & Co. | Method for preparing a film of vinylidene chloride polymer |
| US3565975A (en) * | 1969-07-03 | 1971-02-23 | Dow Chemical Co | Vinylidene chloride polymer compositions |
| US3713965A (en) * | 1970-12-28 | 1973-01-30 | Dow Chemical Co | Non-blocking packaging film comprising an ethylene-vinyl acetate copolymer blended with a fatty acid amide and calcium carbonate |
| US4031162A (en) * | 1971-03-30 | 1977-06-21 | W. R. Grace & Co. | Polymer film with narrow molecular weight distribution and saran and laminates thereof |
| GB1385196A (en) * | 1971-06-23 | 1975-02-26 | Grace W R & Co | Process for the production of laminates |
-
1979
- 1979-12-27 JP JP16949079A patent/JPS55108442A/en active Pending
- 1979-12-27 CA CA000342679A patent/CA1139513A/en not_active Expired
- 1979-12-28 DE DE19792952653 patent/DE2952653C2/en not_active Expired
- 1979-12-31 GB GB7944634A patent/GB2038861B/en not_active Expired
-
1980
- 1980-01-02 DK DK2080A patent/DK2080A/en not_active Application Discontinuation
- 1980-01-02 SE SE8000019A patent/SE8000019L/en not_active Application Discontinuation
- 1980-01-02 BR BR8000002A patent/BR8000002A/en unknown
- 1980-01-02 FR FR8000035A patent/FR2445845A1/en active Granted
- 1980-01-02 AU AU54277/80A patent/AU535896B2/en not_active Expired - Fee Related
- 1980-01-03 AR AR27953480A patent/AR218188A1/en active
- 1980-01-04 NZ NZ19251380A patent/NZ192513A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB2038861B (en) | 1983-05-11 |
| BR8000002A (en) | 1980-09-23 |
| AR218188A1 (en) | 1980-05-15 |
| NZ192513A (en) | 1982-08-17 |
| AU5427780A (en) | 1980-07-10 |
| FR2445845B1 (en) | 1983-12-09 |
| JPS55108442A (en) | 1980-08-20 |
| GB2038861A (en) | 1980-07-30 |
| FR2445845A1 (en) | 1980-08-01 |
| DK2080A (en) | 1980-07-04 |
| AU535896B2 (en) | 1984-04-12 |
| DE2952653A1 (en) | 1980-07-10 |
| SE8000019L (en) | 1980-07-04 |
| DE2952653C2 (en) | 1982-06-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |