New Opportunities for Metallocene Polyethylene …

1 6-2 R halle Abstract New Opportunities for Metallocene Polyethylene in Co-Extruded Blown Films Richard W. halle ExxonMobil Chemical Company A new Metallocene Polyethylene (mPE) family (named Enable mPE) has been developed which exhibits the unique combination of LDPE-like processing and mPE film toughness. This new mPE family allows the converter to eliminate LDPE from many of his film formulations significantly improving film properties while maintaining efficient film production. This new mPE family also possesses shrink characteristics similar to fractional melt index LDPE. This unique attribute has led to the development of new high performance shrink films, which combine these mPEs with more traditional mPEs to obtain down-gauged shrink films with excellent toughness and high stiffness.

2 (MD Tensile at Break, MPa)Stiffness (MD 1% Secant Modulus, MPa)Puncture Resistane(Peak Force, N/ m)Dart Impact(g/ m)MD Tear(g/ m)TD Tear(g/ m)Clarity (%)Shrink (TD Betex at 150oC, %)Holding Force (MD, N)New mPE & mPE-1 resin-based coexNew mPE resin-based monoLD-based (MD Tensile at Break, MPa)Stiffness (MD 1% Secant Modulus, MPa)Puncture Resistane(Peak Force, N/ m)Dart Impact(g/ m)MD Tear(g/ m)TD Tear(g/ m)Clarity (%)Shrink (TD Betex at 150oC, %)Holding Force (MD, N)New mPE & mPE-1 resin-based coexNew mPE resin-based monoLD-based coex High clarity coex films (HCF) can also be made by utilizing these new mPEs as core layers with other mPEs. These films have exceptional clarity, heat sealing and toughness and can be utilized in a wide variety of packaging applications, such as lamination films and stand-up pouches.

3 F ilm C la r ity0102030405060708090 New mPEM onolayerNew mPE CoexNew mPE/mPE-1 CoexGloss0510152025 Haze (%)GlossHaze Another application where the unique performance of these new mPEs is employed is in stiff, cast hand wrap film. These resins allow the converter to tailor the strain hardening behavior of his stretch film to achieve more effective stretch wrapping performance. These new mPEs' improved operational stability combined with their excellent film performance has been found to offer sustainability benefits in many applications. Richard HalleSenior Staff EngineerNew Opportunities for Metallocene Polyethylene in Co-Extruded Blown Films Metallocene Polyethylenes - Review Metallocene polyethylenes (mPE) have changed the shape of the PE film industry.

4 Superior toughness as measured by dart drop impact strength and puncture resistance Good clarity, superior heat sealing performance with high hot tack Excellent mPE properties have led to package redesign and downgauging which has translated into source reduction. Several Metallocene Polyethylene families are produced today. Made using different Metallocene catalysts & processes which generate unique sets of performance characteristics Typically mPEs have narrow, uniform composition and/or molecular weight distributions. Many names - Exceed mPE resin (hereafter mPE-1), mLLDPE, mVLDPE, Exact Plastomers, metallocenes Some mPEs have proven to be processing challenges especially on older blown film lines. Narrow MWDs mean higher melt viscosities and greater extruder motor loads.

5 Low melt strength leads to poor bubble stability without LDPE addition, similar to conventional LLDPE. But, adding LDPE to mPEs or LLDPEs to improve processing significantly degrades their film properties. The addition of -olefins (such as butene-1, hexene-1, octene-1) to the polymer chain introduces short-chain branching (SCB) Minimal effect on melt rheology Significant effect on crystallization, solid state structure andresulting properties Long chain branching (LCB) occurs when branch length exceeds ~ 250 carbon atoms Profound effects on melt rheology; shear and extensional viscosity Little effect on crystallization Significant effects on shear-induced crystallization and the development of orientation during film making process which can have significant effects on film properties Enable mPE resin (hereafter New mPE ): New mPE family with easier processing and excellent toughness.

6 Molecular design combines Long Chain Branching (LCB) and a narrow Composition Distribution (CD). Improved melt strength and greater shear thinning offer good bubble stability and greater extruder outputs vs. LLDPE blends. Ability to replace LLDPE/LDPE blends with 100% new mPE offers improved film properties and the ability to of Polyethylene - Composition and Branching-Short chain branching-Varies by composition , LLDPE, mPE-1-Long chain hyper , HP LDPE-New mPEresin family-Low level of LCBNew mPE ProcessingNew mPEsexhibit: Excellent shear thinning behavior High melt strength101001000100001100 Enable 20-10 ( MI, g/cm )C4 LLDPE ( MI, g/cm )LDPE ( MI, g/cm )LDPE / C4 LLDPE (70%/30%)Typical during extrusionViscosity (Pa s)Flow Curve / 190 oC1001000100001000001100 New mPE-MD( MI, g/cm3)New mPE( MI, g/cm3)C4 LLDPE ( MI, g/cm3)LDPE ( MI, g/cm3)Typical during extrusionViscosity (Pa s)Flow Curve / 190 Output2402102601801401601802002202402602 80LD ( , )New mPE(1MI, )NewmPE-MD( MI, )C4LL (1 MI, )Total output (kg/hr) Index (dg/min)Melt Strength (cN)HP-LDPENew mPELLDPEC ommon LDPE operating rangeMelt Strength by Index (dg/min)Melt Strength (cN)

7 HP-LDPENew mPELLDPEC ommon LDPE operating rangeMelt Strength by RheotensLLDPE/LDPE Blend ReplacementReplacing LLDPE/LDPE blends with New mPE offers improved film properties, the ability to downgauge, and business simplificationLDPEEXTRUDERSLLDPEEXTRUDER SMECHANICAL PROPERTIESPROCESSABILITYE xceed mPEmPE-1 LLDPE-rBlendsLLDPE-rBlendsLDPE-rBlendsLD PE-rBlendsLDPELDPELDPE-r (75% LDPE + 25% LLDPE)LLDPE-r (25% LDPE + 75% LLDPE)NewmPELLDPELLDPEC8C6C4 As a LLDPE/LDPE blend replacement, New mPEoffers improved dart impact, MD tear, and tensile strength Melt temperatures reduced from 224 oC for the 75:25 blend to 202 oC at same melt index Improved bubble stability has potential for increased outputC8-LLDPE/LDPE (75:25)New mPE0000000100200700130035025070 Tensile @Break MD (MPa)1% Secant Modulus MD (MPa) Elmendorf Tear MD (g) Elmendorf Tear TD (g)Dart Drop A (g) Puncture Force (N) Clarity (%) 50 micron filmNew mPE vs LLDPE/LDPE BlendsHot tack curve 0246810121416100110120130140150 Temperature ( C)N/30 mmPerformance Enhancement of mPE FilmsmPE-1/New mPEblends offer significant property improvement versus mPE-1/LDPE formulations:9 Impact: Significant improvement (up to 300%)9MD tear: Significant improvement (up to 300%)9 Tensile strength (MD and TD): Significant improvement9 Hot tack: Higher hot tack peak Broader hot tack window9 Optical properties.

8 Similar clarity Similar gloss0000000500200010010025040080 Toughness MDTensile at Break (N) Stiffness (MD 1% Secant Modulus, N) Puncture Resistance (Peak Force, N) Clarity (%)Gloss (at 45 deg) Dart Impact Resistance (g)Elmendorf MD (g)Core Layer CompositionMelt Index (g/10mins)Density (g/cm3)mPE-1 / LDPE FilmPure mPE PE Films for Enhanced PerformancePhotos used are representative of potential product applications only Meet specific performance requirement Barrier properties High strength, tear Improved sealability Better stiffness/toughness balance High gloss surfaces for printing Reduce cost Reduce amount of expensive polymers Down-gauge with same properties Reduce number of process steps Reduce need for lamination Reduce waste Incorporate recycle layersAdvantages of coex vs monolayer blendsStretch FilmCollation Shrink FilmHigh Clarity CoexClassic High Clarity Coex FilmsConsumer ResinProducer FilmConverters Brand ownersand packersRetailersMIDDLE / BULK LAYER:StrengthOUTSIDE LAYER.

9 Surface propertiesGlossPrintabilityINSIDE Meltindex (g/10 min)Haze (%)Improved opticalsCommon perception : High Clarity LDPE gradesrequired to make a High Clarity Film Introduction mPE resins in the mid 90 s formed the basis for development of high strength clarity coex films and other coex innovations Combining core layer of ZN-LLDPE with skins of LDPE improves overall film performance100% mPE-1 Film25 mRough surface =Poor optical propertiesA : 100% mPE-1C : 100% mPE-1B : 60% mPE-1 40%HDPEHCF (high clarity, high stiffness) Technology30 mExxonMobil s High Clarity, High Stiffness Technology ( % )Haze (%)GlossMonomPE-1 HCFM onolayer mPE-1 Film mPE HCF Technology delivers excellent opticals together with high stiffnessGood optical properties Critical for point-of-sale merchandising High clarity/low haze for see-through packaging High gloss for sharp reverse printingHigher stiffness while maintaining toughness Easier handling film on packaging lines Increases packaging speed Easier to cut Less drape over the edges Stiff films increase package appeal more body to provide luxury feeling Downgauging leads to more sustainable flexible filmsmPE HCF Films Translate into Improved PackagingPhotos used are representative of potential product applications onlyClear.

10 Stiff HCF Coex Films based on New mPEEnable 20-10 Enable 27-05 Enable 20-10 g/cc, MI g/cc, MI50 micron, mm die gap, BURNew mPE-1 New mPE-2 New mPE-1 New mPE-1 g/cc, MINew mPE-2 g/cc, MI50 micron, mm die gap, BURNew mPECoexNew mPE High Clarity Coex density New mPEin the core improves optical performance with a substantial increase in stiffnessMono vs Coex0102030405060708090100monocoex024681 01214 ClarityGloss (45o)HazeClarity and Gloss (%)Haze (%)New mPE-1 New mPE-1 g/cc, MI50 micron, mm die gap, BURNew mPEMonolayerNew mPE-1 New mPE-2 New mPE-1 New mPE-1 g/cc, MINew mPE-2 g/cc, MI50 micron, mm die gap, BURNew mPECoexNew mPEMonolayerTensile @ Break MD (MPa)551% Secant Modulus MD (MPa)233 Elmendorf Tear MD (g)330 Elmendorf Tear TD (g)930 Dart Drop A (g)560 Haze (%) mPECoexTensile @ Break MD (MPa)581% Secant Modulus MD (MPa)301 Elmendorf Tear MD (g)360 Elmendorf Tear TD (g)835 Dart Drop A (g)320 Haze (%)