CA1156812A - Multilayer film - Google Patents

Abstract

MULTILAYER FILM

ABSTRACT OF THE DISCLOSURE
A multilayer film suitable for use in fabricating a trash bag, includes a first outer layer comprising a first heat sealable polyolefin, a second outer layer comprising a second heat sealable polyolefin, and a core layer comprising a blend of a polybutylene homopolymer, and a polypropylene homopolymer or copolymer.

S P E C I F I C A T I O N

Description

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The present inventiDn relates tD a mul~ilayer film, and mDre particul~rly t~ ~ multilayer plastic i.1m su~table fDr use in fabrieating a ~cr~sh b~g.

Generally~ ehPre are a large number Df priDr art plastic films including muleil~yer films ~uitable f~r variDus general ~nd specific applications.
A plastic film suitable for use in fabricating a trash bag must exhibit strong physical prDperties in order tD resist internal and extern21 stresses ~n ~he bag.
Such a bag c~uld ~1s3 be suitable f~r use s ~ cDntainer fDr shipping gD~ds. In additiDn tD resistin~ stresses, it is highly advantageDus if the plastic film is e&sily heat sealable in Drder tD simplify the manufacturing ~peratiDns fDr prPducing the bags. The heat ~ealed ~eams must be strDng and be cApable ~f resisting stresses tendin~t3 bre~k the seams.
The ec~nDmics in prDducing the plastir film must be favDrable and all~w fDr high prDductiDn &peeds.
Generally, le has been fDund in the prl3r ~r~ thfit l~w density pvly~lefin mDnDlayer fl~ms ~dequately s~eisfy many ~f the sequirements f~r ~ fiLm f~r use in Drming tr~sh bsgs. It has been fDund that the u~e ~f 1DW de~sity pDlyDlefin mDnDlayer film f~r lar~e refuse di~pDser b~gs Dften requires ~n lncrease in film gsuge in Drder tD ~aint~in ~atisfactDry physical pr~per~ s. The

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increased film gauge ~ften results ln increased pr3ducti~n CDS~S and ~s ~herefDre cDnsidered undesirable f~r certain applicatiDns .
The instant inve~tion DvercDmes the pri~r ~rt prDblems and prDvides ~ film which can be prDduced ecDnDmically at relatively high speeds and csn be heat sealed tD define str~ng reliable bags.
In accDrdance with the present inventi~n, there is provided a multilayer film suit~ble fDr use in fabricating a trash bag, including a first outer l~yer CDmprising a first heat seal~ble pDlyDlefin, ~ ~ecDnd Du~er layer cDmprising a secDnd heat sealable pDlyDlefi~, and a CDre layer CDmprising ~ blend Df ,B pDlybUt:ylene hDm~7-p~lymer, ~nd a pDlyprDpylene hDmDp~ Der Dr COpDlgmer.
The inventiDn further cDmprises ,a bag fabricated fr Dm th ~ multilayer film.
The present inventiDn also rel~tes t~ ~ method vf prDducing the ~fDrementiDned multilayer film, CDmpriSing the step of cDe~truding said layers thrDugh a single die gap.
It has been determined exper~mentally that the extrusiDn ~f a single l~yer Df the blend Df ~he pDly~utylene hDm~pDlymer and p~lypr~pyleDe p~lymer~ esp2cially fDr l~w mel~ 1DW v~lues, dDes ~Dt res~le in an accept~le film for a film having a thickness o about 1D5 mils or l~ss.

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Thus, a single layer film Df the blend Dr a tws layer thin film havlng a one layer of the blend is unacceptable.
F~r these films, the thickness is n~t unif~rm snd many D
hDles in the film ar~ fDrmed. The appear~nce ~f a hDle ~nterferes with ~he fDrm~tiDn Df ~ "bubble" ~n carrying ~ut the blown film extrusiDn.
The suitable heat sealable pDlyDlefins include c~pDlymers Df ethylene vinyl acetate and e~hyl~ne ethyl acrylates each ~ving C~mDnDmer c3ntents Df frDm ab~ut 0 1% tD 30~/O ~y we;.~ht 2nd ~ r~elt flDW Df fr~m ab~ut 0.3 ~c~
ab~ut 10.0 decigrams per mirlute. Suitable pDlyDlefins fu~her include pD~yethylene h~vîn~ a density of frDm abDut 0.916 tD abDut 0.962 ~rams per eubic centimeter and having 5 melt flow Df frDm ab~u~ 0.1 tD ~bos~t 10 dec igrA ms per minu te .

ferably, the et:hylene vinyl acetate c~31ymer ~nd ethylene ethyl ~cryl~te cDpDlymer each has 8 CDmDnt~mer cDn~cer~t ~f ~om a~t lP/I, t:o abou~c 20~/~, by weight 8nd melt 1~w ~f fr~m abo~lt a3 ltD about 5 decigrams per minute.

Preferably, the pDlyethylene has a density Df fr~m about 0.916 t~ about ~.930 ~ram per cu~ic centimeter ~nd a ~elt fl~w ~f rDm ab~ut 0.1 t~ ~b~ut 6 dec~grams per minute.

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~ r ~he cDre layer, pDlyprDpylene pDlymer h~ving a density Df ~rDm abDut û.89 ~ ~b3ut 0.~1 gram per cubic centimeeer snd ha~,ring ~ ~elt fl~w ~f frDm ElbDut 0.5 tD
~bDut 15 decigrams per minu~e is prefer~ble.
Generally, f~r the c~re layex,the pDlybutylene hDm2p~1ymer has a dens~ty Df frDm ~b~ut 0.90 tD about 0.92 gr~m per cubic centimeter and a melt fl~w Df from ab~u~
0.4 t~ ab~ut 10 decigrams per minute.
Preferably, ~ f the pDlymers used in the 10 - inventi~n are film ~rade.

Generally, the Dverall thickness Df the film ~f the inventiDn can be frDm abDut ~.5 t~ abDut 10 mils.
Preferably, the ~verall thickness i5 fr~m ~bout 1 tD
about 3 mils. The cDre layer is fr~m abDut 10% tD ab~ut 90~/O ~f the Dverall thickness. M~st ~f the strength Df the ~lm is derived ~rDm the core l~yer.

Preferably, the blend ~f the pDIybutylPne hDm~pDlymer end the pDlypr~pylene p~lymer is in equal ~m~unts. The blend can range fr~m about 10% ~ ab~ut 90% ~Dy weight Df ~ne pDlymer with the b~iance bein8 .he 3ther, prefer~bly 2:1 tu 1:2.

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In general, ~arious conventional additlves ~uch as 81ip agents, antibl~cking agents, and pigments can be incorporated in the film of the invention in accordance with the conventional practice.
The properties of the polymers de6crlbed herein as well as the test results reported herein hsve been measured in accordance with the following test methods:
Density: ASTM D-1505 Melt Flow: ASTM D-1238 Polypropylene Polymer - Condition L
Polybutylene Homopolymer - Condition E
Ethylene Vinyl Acetate - Condition E
Polyethylene Polymer - t,ondition E
Puncture Toughness: Genera11y this test includes driving ~ l/2 inch round probe at the rate of 20 inches per minu~e against a sEmple of film. The load a~ puncture is measured along with the area under the load-elongation curve (ener~y).
Tensile Stren~th: AS~M D-882 - Method A
Tensile Energy: Energy of film to fracture f~r ASTM D-~82 - Me~h~d A
Dart Drop: ASTM D-170~ (50% failure~
Heat Seal Strength Test: Two one-inch wide trips of film are ~Paled to each other at a central por~isn and subjected to ASTM D-882 until deiamination or a break occurs.
30 ! Elmendorf Tear: ASTM D-1922 1 l~V

All percentages and parts given herein are by weight unless Dtherwise indicated.
The blDwup ratiD as used herein ls the ratiD Df the flat width Df the bl~wntube Df film tD the exit diameter cf the die.
The drawdDwn rati~ as used herein is the rati~ of the exteri~r g~p Df the die ~nd the thickness Df the drawn film.

IllustrativP, n~n-limiting examples Df ~he prac~ice D the inventi~n are set ~ut belDw. NumerDus Dther examples c~n readily be ev31ved in the light ~f the guiding principles and teachings cDntained herein. The examples given herein are intended tD illustrate the inventiDn and nDt in any sense t~ limit the manner in which the invention can be practiced.
~ able 1 shDws the pDlymers used in the examples herein.

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Table 1 C Dmmer c i~ 1 Melt F1DW Identifica$ion PDlymerd~/min. _~ nd _ a P~E A 2.Q PDlyethyleneDY~ 9 Un~n CRrbide density:Curp~rat1 Dn O . 919 g/cc P-E B 0. l P~lye~hylene dens i ty:
O . 917 ~/cc P-E C 0 ~ 3 PDlyethyleneDGDA 6093 Unibn dens i ty:Carb ide C orp .
~ . 953 ~,/cc P-P A 0.6 P~lypr~pyleneShell 5220, Shell HDmDpDlymerChemic.q 1 CDmpany desls ity:
0 . 905 ~/cc P-P B 3.0 PolyprDpyleneRexene PP 44J3, CopolymerRexene P~lymers CD.
dens i ty:
O.90Q g/c~
P-P C 4.0 PDlyprDpyleneHercules Pr~fax ~531, CDPD1Ymer~ercules Chem CD.
dens i ty:
0.900 g/cc P-P D 7.0 PolyprDpyleneRe~cene PP 4451, Homop~ erRexene P~lymers Co.
de~s ity:
O. 9Q5 ~3/cc ~-P E 12.û PGlypropylenePP 58l8, Di~mDnd Ccp~lymerShamrDC}C Chem, Co.
density:
O 899 g/cc ~c Dntinued) ~ 5~ ~2, 12150 (continued) Commercial Melt Flow Identification Polymerd~/min. De~criv~ and Source _ P-B A 1.0 Polybu~yleneShell 1600, Shell HomopolymerChemical Co.
density:
O. 910 g/cc P-B B 2.1 PolybutyleneShell 1200, Shell density: Chemical Co.
O. 910 g/cc EVA A 1.0 Ethylene DQDA-lB24, ~nion Vinyl AcetateCarbide Corp.
4% vinyl acetate Examples 1 and 2 ~ or Example 1, a multilayer film according to ~he instant invention was produced in accordance with con~entional blown film coextrusion me~hods using a three layer spiral-channel die having a di~eter of 12 inches to fo~m a tube of the film. An EGAN die was used. The exterior die gap was 30 mils. The blowup ratio was about

3:1 and the drawdown ratio was about 20:1.
Three ~eparate ex~ruders were used. Eaeh extruder was supplied with the polymer for for~ing one of ~he layers for the film. Eaeh extruder was arranged to feed a ~eparate ha~nel ~ the three layer die. The multilayer film was e~truded through the ~ingle die gap. While the multilayer film had o~ly three layer~, it is p~ss$ble to ha~e additi~nal layer~ by using additional e~truders and a ~ultil~yer die having B number of channels coIresponding to the ~umber of extruders u6ed.

1~150 Each Df the Duter l~yers was pDlymer P-E A ~nd the cDr~ lsyer was ~n equal blend Df pDlymerS P-P A and P-B B.
The Dverall thickness ~f the re~ulting film was abDut 1.5 mils and the CDre layer thickness w~s abDut 45~/D Df the total film thickness. The inner and ~uter layers had abDut the same thickness.
Example 2 was ~ m~nDl~yer film Df p~lymer P-E A als3 prDduced by a s~ilar bl~wn film pr~cess and subjected 0 ~D similar blDwup and drawdD~ ratiDs.
Ta~le 2 cDmpares ~he physical prDperties ~f the ilms ~f Examples 1 ~nd 2 tD each t)ther and includes ~ypical values f~r 8 typical pri~r art film h~ving a thickness of ~bDut 1.5 mil.
TAble 2 ~Inventi~n) (MDnDlayer) Typical Pri~r PhYsical PrPpertv Example 1 ExamPle 2 Art Film Pun~ TDughness ~ ~ -- 6~3 ~--l~ad (lbc.) Punc~ure T~ughness20.0 4.5 4.8 e~ergy (inch-lbs.) Tensile Strength MD 5700 2400 3100 (lbs . /~n2) TD4700 2~00 1~00 TenslleErergy MD 46 21 20 ~in.-lbs~) TD 40 29 27 Dart Drop (g.) 132 85 90 ~0-.L~ LJV

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~ rDm Table 2~ it is evident that the film of the lnstan~ inventiDn~ Example 1, pDssesses superi~r physical pr~perties wi~h respect tD the mD~ yer film ~f Exa~ple 2 as well as the typical priDr ~rt film.

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, Examples 39 4, and 5 were carried DUt in an ende~vDr ~ cDmpare the physical prDper~ies ~f films ~f the instant inventi~n f~r different pDlyprDpylene p~lymers.
~ilms were prDduced fDr the Ex~mples 3, 4, and 5 in accDrdance with the prDcess ~f Example 1 and with the same Duter l~yers and the same rat:iD fDr the blend except that an Egan die having a diameter Df 8 inches and ~n exterior gap ~f 35 mils was used. The pDlypr~pylene pDlymer f~r each of the examples 3 4, and 5 is shDwn in Table 3 along with the measured physical prDperties. Each ~f the films fDr the Examples 3, 4 &nd 5 had an Dverall ~hic~ness of &b~ut 1.5 mil ~nd the ~hickness Df each layer was abDut equal tD e~ch Dther. FDr e~ch ~ilm, the blDwup rati~ w~s abDut 4:1 and the drawdDwn ratiD was ab~ut 35:1.5.

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T~ble 3 Phys ica 1 Examp l e 3 ~ ExamP 1 e 5 PDlypr3pylene polymer in core layer P P A P-P IB P-P C
Puncture TDughness 9.7 6,.9 4.7 l~ad (lbs. ) Puncture TDughness 13.3 5.~ 4.8 energ (in.-lbs . ) Tens ile Strength MD 4000 4100 3700 (lbs./in.2) l'D 3800 3000 3200 S Dme var ia t i Dn in the pr Dper t ie s D f the f i lm D f Example 3 as c~mpared tD the film of Ex&mple 1 is evider-t perhaps due t~ the different blDwup and drawdDwn ratiDs.
Fr3m Table 3, it can be seell that the film of E~ample 3 had the best physical prDperties. Fr~m Table 1, it can be seen tha~ p~lymer P-P ~,has a lower melt f1DW
as e~mpa~ed tD PD1YmerS P~P B and P-P C Qnd is preferable.
~'7 ' _ E~amples 6 a~d 7 were carried ~ut ~n Drder tD
cDmp~re the physic~1 prDperties Df films fDr different cDre lager ehicknesses. ~he films ~r ~he ~:xamples 6 and 7 ~?ere prDduced ln ~ccDrd~nce with the prDce~ used f~r pr~duc ing the films Df the E~amples 3 ~ 5 ~ e~ch Df ~he e films ~ncluded l~yer6 h~ving the ~une pol~rmer as in the ilm Df the E:~a~ple 1. ~ble 4 sh~ws 8 c~mparison between the ilms ~f the Ecamples 6 ~nd 7.

~ 2 Table 4 _ Physical PrDperties Example 6 Example 7 CDre thickne~s as ~/~ 4 cf Dver~ll thickness 5% 33%

Puncture Toughness 9.O 9.7 lDad (lbs.) Puncture T~ughness 20.0 13.3 energy ~in./lbs.) Tensile Stren~th (lbs./in.2) MD 5700 4000 Table 4 shDws that the core layer provides impr~ed physical pr3perties f~r an increased thickness.

~xamples 8 and 9 Examples 8 and 9 were eRrried ~ut in Drder to ecmpare films having different am~unts of polypropylene pDlymer in the eore l~yer. The films fDr the Examples 8 a~d 9 were pr~duced in ace~rdance with the prDcess used f DS the films ~f the Examples 3 ~c 5.

Table 5 Physic~l Pr~perties ~ ~
% Df P-P A in 50% 67%
C Dre layer Puncture Toughness lDad (lbs.) 9,7 6.0 Punc ture T~ughness energy (in.-lbs.)13.3 6.6 Dart Dr~p (g,) 132 52 From Table S, it can be seen that increasing the amDunt Df pDlypropylene pDlymer in the CDre layer reduces the impact prDperties Df the film Df the inventi~n.

Examples 10 and 11 Examples 10 snd 11 were carried DUt in order t~
compare the physical properties ~f tW3 films which hsve the ~ame fir5t Duter layers ~nd cDre layers ~nd different ~ecDnd Duter layers- FDr this purpDse~ tWD films were made in accordance with the prQcess Df the Examples 3 tD 5 with each film having a thickness Df abDut 3.0 mils instead o~ 1.5 mll ~nd having l~yer thickness in the r~tlD of 1:~:3. F~r each film, the first Du~er l~yer was pDlymer P~E A ~nd the cQre l~yer was ~n equ~l blend ~f the p~lymer P-~ B and P-B A. FDr the Example 10, ~he ~ecDnd ~uter l~yer was pDlymer P-E A ~nd f~r ~he ~xample 11~ the secDnd ~uter l~yer was an equal blend ~f ~he pDlymers P-E A
and EV~ A.

~.~ S6 ~2 Table 6 ~hows ~ comparison between the measured physical propertie~ of the films ~f the Examples ~ and 11.
This ~h~ws the superiority ~f the blen~ used~in Exa~ple 11 ' ' 85 a heat sealing layeY.

Table 6 _ Physical ~pertiesExample 10 ~ E~

Dart Dr~p (g.)315 241 Puncture T~ughness 10.0 9~6 l~ad (lbs.) 1~ Puncture T~ughness` 12.2 9.8 energy ~in.-lbs.) Elmendurf Tear (g~) MD 1046 ~3 .TD 1024 1386 Tensile s~rength (l~S./in, ) MD 3300 3900 ~eat Seal Streng~h Test (lbs.) 3.5 5 o6 ~a~
Examples 12, 139 14 ~nd i5 were earried DUt ~n ~rder t~ cDmpare the physical pr~perty Df films h~ving di~ferent blends fDr the cDre layers. A film having ~ thickne~s of 3.0 mils and a ra~i~ Df layers Df 1:2:3 was prDduced ln accordance with ~he proee~s ~f the Examples 3 tD 5. ~he ~uter l~yers of eaeh ~f the films ~ere ~he pDlymer P-E A ~nd the c~re l~yers were a ~lend Df P-P B and P-B A with t~e r~tiD ~f P~P B:P-B A as shDwn ~able 7~

- . 12150 Tab 1 e 7 ___ Physical Ex~mple Example ~xample Example PrDperties 12 13 14_ 15 ~p B:P-B A 0:100 20:80 35:65 S0:50 Dart Drop (g.) 34~ 272 230 315 Puncture T~ughness 11.1 8.6 9.1 10.0 lDad (lbs.) Puncture TDughness 11,4 10.8 9.B 12.2 energy (in.-lbs.~

Elmendorf Te~r ~-) MD 1202 ~23 526 1046 - -TD 15~0 1101 lQ93 1027 Tensile S~ ength (lbs./in. ~ MD 3200 3400 3400 3300 Heat Seal Streng~h 2.9 4.5 "
~lbs.) The film Df the Example 12 tended t~ delaminate during the heat seal ~trength test ~ that a .
6~re ~f 100% pDlybutylene is unacceptable. The f~lm ~f the Example 13 perf~rmed be~ter than he film ~f ~he Example 12 during the Heat Sezl Strength Test and the films uf the Examples 14 and 15 showed s~me del~mina~iDn during the Heat Seal St~eng~h Tes~. Previ~us tests f~r c~mparRble ilms havi~g a thickness Df abDut 1O5 mils ~hDwed delamination.

les 16~ 17 _nd 18 Example~ 16, 17 and 18 were carried ~ut S~
further CDmpare films h~ing c~re layer~ with different ble~ds. EaEh ~iL~ h~vlng ~ thic~Dess ~f 1.~ nd ~16~
., ) U

rati~ Df layers ~f 1:1:1 was prDduced in accDr~ance with the prDcess Df the Examples 3 ~D 5. The Duter layers fDr the ilms were pDlymer P-P B while the core layers were blends Df pDlymers P-P B and P-B A with the ratiD ~f P-P B:P-B A as shDwn in Table 8.

Table __ Physical Dperties Example 16 ~ Example 18 P-P B:~ B A 50:50 67:33 lOû:û
-- Dart Dro~ (g.) 84 90 less ~han -50 Puncture T~ughness5.3 5.2 __ load (lbs.) Puncture T~u~hness 4.6 3.8 ,_ energy ~in.-lbs.~
Elmendorf Tear -) MD 330 370 less than 20 TD 1090 880 __ Tensile s ~ ength (lbs./in. ) MD 4070 4300 __ TD3100 3~00 The films ~f the Examples 16 ana 17 were ~DQd ~eress the film Df the Example 18 was very ps~r. ~us, cDre l&yer c~f 100% pDlypropylerle is n~t ~atisfac~cDr~
~t ~11.

~ 5 Examples 19 nd ~0 Ex~mples 19 ~nd 20 were carried DUt ln Drder tD
CDmpare the physical prDperties of two f~ms having core layers with diff~rent pDlybutylene hDmDpolymers.
Ihe films for the Examples l9 and 20 were m~de in accordance with the process Df the film ~f the Example 15, The film for the Example 19 was similar tD the film ~f the Example 15 and the film for the Example 20 used P-B B
fDr the cDre layer. The physical prDperties for the -- Example~s l9 and 20 are shown in Table 9. Each film had - _ B thickness of about 3.0 mils.

Table Physical Properties ~x~ 19 Polybutylene H~mopolymer P-B A P-B B
D~rt Drop ~.) 315 211 Puncture TDughness10.0 10.5 lDad (lbs.~
Puncture Tou~hness energy 12 . 2 1~ . 4 ZO (in.,olbs . ) ELmen~Drf Tear (g.~ MD 1046 763 TD lG27 1015 Tensile S~rength (lbs./in ) MD 3300 3300 . ~2150 ~'S~

The film Df the Ex~mple 19 exhibits s~mewhat better physical prDpertieS than the film Df the Example 20 SD that it 6hDWS that the lDwer value ~f ~elt fl3w f~r the pDlybutylene is preferable.
Examples 21, 22, and 23 Examples 21, 22, and 23 were carried Dut in Drder tD c~mpare the physical pr3perties Df films having different layer ratiDs. Films fDr the Examples 21, 22, and ~3 were made with 3uter layers Df pDlymer P-E A and c~re layers ~f a blend Df equal ~mDunts ~f pDlymers P-P B and P B B. The same prDcess as described fDr the Examples 3 ~ 5 was used, but the rati~ Df the layers fDr the respective films was as sh~wn in Table 10. The fi.lm thickness fDr each example was ab~ut 1.5 mils.
Table 10 Physical ~ ~ Example 22 Example 23 RatiD Df 1 yers 1:1:1 2:1:2 3~

Dart Drvp (~.~ 88 84 88 Puncture TDughness 5 3 5.2 5.2 l~d (lbs,) P~cture Toughnes s 4 . 6 3 . ~ 4 . O
enelgy (in.-lbs.) ElmendDrf Tear (g~) ~D 330 ~20 210 TD lOgO 8gO 910 Tensile Strength (lbs./in.~3 MD 4~70 3800 3500 TD 3100 2800 ~800 ~19~
I

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The Example 21 had the gre~test cDre thickness and als~ had ~he best physieal prDperties.
~: n~le~ d ~-Examples 24 and 25 were carried GUt ~n DrdPr tDmeasure the physical properties of tWD films made in acc~rd~nce with the Example 19 but with the blDwup Tatios as shDwn in T~ble 10. Each film had ~ thickness DI 3.0 mils.

Table lO

Physical 10 Properties Example ~4 Example 25 ____ Blow Up Ratio 3.0 4 0 Dart ~rDp (g,) 211 214 Puncture ~Dughness 10~1 10.5 lDad (lbs.

Puncture TDughness 12.1 12.
energy (in.~lbs.) E~mendorf Tear (g.~ MD 615 763 T~nsile StIeng~h ~lbs./in.2~ MD 3200 3300 The fiLm Df the Example 7.5 with the higher blowup ~at~ exhib~ted ~omewha~ better physleal pr~per~ies and is prefer~ble, -2~-~ 12150 I wish i~ to be ~nderstood that I do not desire to be limitPd to the exact details of construction shown and described 3 for obvious modifications will occur to a person skilled in the art.

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Claims (30)

WHAT IS CLAIMED IS:

1. A multilayer film suitable for use in fabri-cating a trash bag, includes a first outer layer comprising a first extruded heat sealable polyolefin; a second outer layer comprising a second extruded heat sealable polyolefin;
and an extruded core layer comprising a blend of a poly-butylene homopolymer having a melt flow of from about 0.4 to about 10.0 decigrams per minute, and a polypropylene homopolymer or compolymer having a melt flow of from about 0.5 to about 15.0 decigrams per minute.

2. The multilayer film of claim 1, wherein at least one of said polyolefins comprises polyethylene having a density of from 0.916 to 0.962 gram per cubic centimeter and having a melt flow of from 0.1 to 10.0 decigrams per minute.

3. The multilayer film of claim 2, wherein said polyethylene has a density of from 0.916 to 0.930 gram per cubic centimeter and a melt flow of from 0.1 to 6.0 decigrams per minute.

4. The multilayer film of claim 1, wherein at least one of said polyolefins comprises a copolymer of ethylene ethyl acrylate or ethylene vinyl acetate, said one polyolefin having a comonomer content of from about 1% to about 30% by weight and having a melt flow of from about 0.3 to about 10.0 decigrams per minute.

5. The multilayer film of claim 4, wherein said one polyolefin has a comonomer content of from about 1% to about 20% by weight and a melt flow of from about 0.3 to about 5.0 decigrams per minute.

6. The multilayer film of claim 1, wherein said polypropylene homopolymer or copolymer has a density of from about 0.89 to about 0.91 gram per cubic centimeter.

7. The multilayer film of claim 1, wherein said polybutylene homopolymer has a density of from about 0.90 to about 0.92 gram per cubic centimeter.

8. The multilayer film of claim 1, wherein said blend comprises from about 10% to about 90% by weight of said polybutylene homopolymer and from about 90% to about 10% by weight of said polypropylene homopolymer or copolymer.

9. The multilayer film of claim 1, wherein the weight ratio of said polybutylene homopolymer to said polypropylene homopolymer or copolymer is from about 1:2 to about 2:1.

10. The multilayer film of claim 9, wherein the weight ratio is about 1:1.

11. The multilayer film of claim 1, wherein the thickness of said film is from about 0.5 to about 10 mils.

12. The multilayer film of claim 11, wherein the thickness of said film is about 1.5 mils.

13. The multilayer film of claim 1, wherein the thickness of said film is about 3.0 mils.

14. The multilayer film of claim 1, consisting essentially of said first outer layer, said second outer layer, and said core layer.

15. A bag fabricated from the multilayer film of claim 1.

16. A method for producing a multilayer film, comprising the steps of supplying to three separate extruders respectively first and second heat sealable polyolefins, and a blend of polybutylene homopolymer, and a polypropylene homopolymer or copolymer with each extruder feeding a separate channel of a multilayer die and extruding through a single die gap a multilayer film including first and second outer layers of said first and second polyolefins, respectively, and a core layer including said blend.

17. The method of claim 16, wherein at least one of said polyolefins comprises polyethylene having a density of from 0.916 to 0.962 gram per cubic centimeter and having a melt flow of from 0.1 to 10.0 decigrams per minute.

18. The method of claim 17, wherein said poly-ethylene has a density of from 0.916 to 0.930 gram per cubic centimeter and a melt flow of from 0.1 to 6.0 decigrams per minute.

19. The method of claim 16, wherein at least one of said polyolefins comprises a copolymer of ethylene ethyl acrylate or ethylene vinyl acetate, said copolymer having a comonomer content of from about 1% to about 30%
by weight and having a melt flow of from about 0.3 to about 10.0 decigrams per minute.

20. The method of claim 19, wherein said copolymer has a comonomer content of from about 1% to about 20% by weight and a melt flow of from about 0.3 to about 5.0 decigrams per minute.

21. The method of claim 16, wherein said poly-propylene homopolymer or copolymer has a density of from about 0.89 to about 0.91 gram per cubic centimeter and a melt flow of from about 0.5 to about 15.0 decigrams per minute.

22. The method of claim 16, wherein said poly-butylene homopolymer has a density of from about 0.90 to about 0.92 gram per cubic centimeter and a melt flow of from about 0.4 to about 10.0 decigrams per minute.

23. The method of claim 16, wherein said blend comprises from about 10% to about 90% by weight of said polybutylene homopolymer and from about 90% to about 10%
by weight of said polypropylene homopolymer or copolymer.

24. The method of claim 16, wherein the weight ratio of said polybutylene homopolymer to said polypropylene homopolymer or copolymer is from about 1:2 to about 2:1.

25. The method of claim 24, wherein the weight ratio is about 1:1.

26. The method fo claim 16, wherein the thickness of said film is from about 0.5 to about 10 mils.

27. The method of claim 16, wherein the thickness of said film is about 1.5 mils.

28. The method of claim 16, wherein the thickness of said film is about 3.0 mils.

29. The method of claim 16, further comprising the step of fabricating a bag from a portion of said film.

30. The method of claim 29, wherein said bag is fabricated by heat sealing.