Enhanced EVOH for Improved Orientability and Shrink

PVdC Alternative for High Barrier Meat & Cheese Packaging

Presented by:

Gene MedlockSenior Research EngineerKuraray America – EVAL Business Unit

OutlineOutline

Introduction to EVOH

Barrier Shrink Bag Application Overview

New EVOH Technology for PVdC Alternative

Results of PVdC Benchmarking Evaluations

Conclusions

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EVOH is a random copolymer ofEVOH is a random copolymer of

EthyleneEthyleneand and

VinylVinyl--AlcoholAlcohol

mol% ethylene contentmol% ethylene content

Introduction to EVOHIntroduction to EVOH

2424 M100M1002727 L171L1713232 F101/F171/F104F101/F171/F1043535 C109C1093838 H171H1714444 E105/E171E105/E1714848 G176G176

Higher formability/orientabilityHigher formability/orientability

Higher Gas BarrierHigher Gas Barrier

(CH(CH22--CHCH22))mm (CH(CH22--CH)CH)nn

OHOH

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Oxygen Transmission Rate of EVOH vs. Various Other Polymers

EVOH – 32 mol%EVOH – 44 mol%PVDC copolymer (Extrusion Grade)O-PAO-PETHDPECPPPCLDPEEVA

0.41.52.6

38.054.0

2300.03000.05000.0

10000.018000.0

OTR (20oC, 65%RH)POLYMER

Units : cm3・20μm / m2・day・atm

Oxygen PermeabilityOxygen Permeability

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EVOH Resin ApplicationsEVOH Resin Applications

FlexibleBottles Formed

Automotive PFT Agri-chem Bottles

Under floor Heating PipeCosmetics

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Barrier Shrink Bag StructuresBarrier Shrink Bag Structures

PO/PVdC/PO

PO/PA/PO

PO/PA/EVOH/PA/PO

PO/EVOH/PO

Vast majority of boneless and bone-in meat pkg. & cheese

pkg.

Very small % of bone-in

meat structures

Small % of boneless meat and cheese

structures

No commercial structures

(boneless only)

Development of alternative films and processing technology for barrier shrink

bags is accelerating…

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Volume of Barrier Resin Used in Shrink FilmsVolume of Barrier Resin Used in Shrink Films

PVdC

EVOHEVOH

25,150 MT

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Applications for EVOH in Shrink FilmsApplications for EVOH in Shrink Films

EU

Current commercial shrink film structures are EVOH/PACurrent commercial shrink film structures are EVOH/PA

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Unique Challenges in Double Bubble Film ProcessUnique Challenges in Double Bubble Film Process

Performance targets include:Orientability

High orientation ratioLow resistance to deformation

Shrink propertiesHigh shrink ratio at low temp

Oxygen BarrierTo meet required shelf life

Thermal stability Significantly better than PVdC

Thermally induced dehydrochlorination at temperatures very near processing temperatures Brown color

First bubbleFirst bubble

CoolantCoolant

DieDie

CoolingCoolingDeviceDevice

ExtruderExtruder

PreheaterPreheater

HeaterHeater

Second bubbleSecond bubble

AnnealingAnnealingunitunit WinderWinder

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4. Shrink in hot water shower tunnel

5. Chilling (water bath)

6. Put in box

3. Vacuum pack and seal1. Cut beef

2. Put beef in bag

Meat Packaging ProcessMeat Packaging ProcessProcess: Vacuum packaging Shower tunnel Water quenching

80oC – 3 sec10

Target for New DevelopmentTarget for New DevelopmentBarrier and Shrink Property of Commercial Product

20

30

40

50

60

70

80

1 10 100

OTR(cc/m2.day.atm @20C-85%RH)

Shr

ink

ratio

(% a

s A

rea

@80

C-1

0sec

)

PVDC Structure

EVOHstructure

Improved

Shrink

Target for Development:• Improve shrink property• Preserve barrier property

Target for Development:• Improve shrink property• Preserve barrier property

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New DBS (Double Bubble Shrink) TechnologyNew DBS (Double Bubble Shrink) TechnologyDevelopment grade of DBS EVOH technology is XEP-1232

Enhanced 38 mol % EVOH using new technology

Structure-properties of new DBS technologyThermal analysisEvaluation of viscoelastic propertiesBiaxial orientation tests

Monolayer filmsConstant and increasing strain rate tests

Shrink performanceOxygen barrier properties

Evaluations were conducted to compare XEP-1232 vs.

1. Conventional 38 mol% EVOH and

2. PVdC (polyvinylidene chloride)12

Thermal Analysis Thermal Analysis

Conventional 38 mol% EVOH

DBS EVOH

DBS EVOH Technology reduces Tm and Tc by ~25°CTg reduced by ~10°C

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1.0E+07

1.0E+08

1.0E+09

1.0E+10

-50 0 50 100 150Temperature (oC)

E' (

Pa)

Conv. 38 mol% EVOH

DBS EVOH

Viscoelastic PropertiesViscoelastic Properties

Improved viscoelasticity

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Biaxial Orientation Stretch EvaluationBiaxial Orientation Stretch EvaluationInstrumented Simultaneous Biaxial Orientation

Orientation Ratios (equi-biaxial): 2X2, 3X3, 4X4 and max (>5X5)Strain rate: 5 meter/minTemperatures: 80oC, 90oC and 100oCn = 3

EVOH materialsConventional 38 mol% grade EVOHDBS EVOH gradeSample specimens produced via cast film extrusion

PVdC materialCopolymer of vinylidene chloride and methyl acrylateSample specimens produced via 2-step compression molding process using raw PVdC powderSamples conditioned just prior to testing to reverse secondary crystallization

Conditioning method: Re-heat films in hot press at 175oC for 45 seconds, followed immediately by quick quenching in cold water

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BiBi--Axial Stretch TestAxial Stretch Test

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Key Biaxial Orientation Stretch Test ResultKey Biaxial Orientation Stretch Test Result

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BiBi--Axial Orientation Inflation EvaluationAxial Orientation Inflation EvaluationInstrumented biaxial orientation by inflation

Orientation ratio: up to 4X4 (approximation) Strain rate (variable): up to 300 %/s Temperatures: 80oC, 90oC n = 3

EVOH materialsConventional 38 mol% grade EVOHDBS EVOH gradeSample specimens produced via cast film extrusion

PVdC materialCopolymer of vinylidene chloride and methyl acrylateSample specimens produced via 2-step compression molding process using raw PVdC powderSamples conditioned just prior to testing to reverse secondary crystallization

Conditioning method: Re-heat films in hot press at 175oC for 45 seconds, followed immediately by quick quenching in cold water

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Laser to Measure Inflated Specimen Height

Stress Engineering Services (SES) – Cincinnati, OHBi-axial inflation test for acquiring stress vs. strain and strain-at-failure data for plastic films over a range of strain rates

BiBi--Axial Inflation TestAxial Inflation Test

1. Flat specimen is clamped to test structure and pressurized

2. As specimen is inflated, the height of “bubble” is measured to calculate strain

3. Stress is calculated in the material using measured pressure in bubble and formula for thin walled pressure vessel

4. Assumption is spherical deformation

5. Air pressure (strain rate) adjusted by pressure regulator controlled by voltage proportional controller

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BiBi--Axial Inflation TestAxial Inflation Test

Samples are heated by elements on the underside of fixture

Thermocouple and controller control the heat of plateSpecimen is allowed time to reach specified test temperature

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Key Biaxial Inflation Test ResultKey Biaxial Inflation Test Result

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Shrink TestingShrink TestingAnalysis of oriented monolayer specimens from bi-ax stretch evaluationOriented film shrinkage measured at 80°C and 90°C

Shrink bath time = 3 seconds

Specimen size: 4” square for 4X4 (cut from center of oriented film)

Made pre-shrink gauge profile

Measure dimension of post shrink specimensn = 4

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Key Shrink Result Key Shrink Result

DBS EVOH shrink72% at 80oC shrink temp83% at 90oC shrink temp

PVdC yielded no shrink at 80 or 90oCPossibly due to secondary crystallization in stretch testPO/PVdC double bubble film yields shrink 65 – 85%

Samples from 80Samples from 80ooC C -- 4x4 Orientation4x4 Orientation

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Oxygen Barrier PropertiesOxygen Barrier PropertiesOTR (cm3.20μm/m2.day) at 20°C

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ConclusionsConclusionsNew DBS EVOH offers significantly improved orientability

New DBS EVOH also provides high shrink-ability at low temperatures, comparable to PVdC

DBS EVOH yields good preservation of barrier properties despite reduction in crystallinity

DBS technology may be utilized in other barrier applications where improved formability or orientability is required

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AcknowledgementsAcknowledgementsKuraray Co., LTD.

Hiroyuki ShindomeTakeyuki IgarashiShinji Tai

Stress Engineering ServicesDiana BrownRay Newman

IMI CNRCNathalie ChapleauMichel Carmel

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Thank you

PRESENTED BY

Gene MedlockSenior Research EngineerKuraray America EVAL Business Unitgdm@kai.us.com

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