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March 3-5, 2009www.healthpack.net

Building Sterile Barrier System MaterialsOptimizing Cost and Performance

Dhuanne DodrillRollprint Packaging Products, Inc.

Sterile Barrier System Materials• May consist of a single layer

– Many rigid tray structures– Uncoated Tyvek

• More often are composite structures– Layers are used to provide functionality

• Heat-Stable Layer• Barrier Layer• Bulk Layer• Sealant Layer• Bonding Agents

– Adhesives– Tie Layers– Primers

Creating an SBS Material

• Blown Film• Cast Film• Solventless Laminating• Adhesive Laminating• Solution Coating• Extrusion Laminating• Extrusion Coating

Blown Film

Extruder A

Extruder B

Extruder C

Die

Bubble

Collapsing Frame

Winder AWinder B

Blown Film

Blown Film

Extruder A

Extruder B

Extruder C

Die

Bubble

Collapsing Frame

Winder AWinder B

Blown Film

Blown Film• Very economical• Ideal for thermoforming applications• Relatively poor thermal stability• Relatively poor dimensional stability• Limited material choices (low m.i.)• Good balance of mechanical properties (MD vs TD)• Is possible to orient the film

Blown Film• Can have multiple layers• Tie layers used between dissimilar materials

– Modified polyethylene– Modified polypropylene– Typically, maleic anhydride

Cast Film

Extruder

Tenter Frame

Cast Film

Cast Film

Extruder

Tenter Frame

Cast Film

Cast Film

• Economical• Can have multiple layers

– Tie layers used between dissimilar materials• Better optical properties than blown films• Can emboss the surface in line• Stiffer films due to faster quenching• Can orient to improve dimensional stability• Higher processing speeds than blown films

Cast Film

• Standing gauge bands a concern• Higher scrap rates than blown films because

edges must be trimmed• Equipment is more expensive than blown film

lines• More limited range of widths from same die• Requires higher processing temperatures• Much less capacity on cast lines

Laminating & Coating

• Much more versatile than blown or cast film processes

• Create composites of very different materials

Solventless Laminating

Primary Web

Secondary Web

Nip Roll

Finished Web

Adhesive Application


• Solvent-free• Relatively low capital investment and low

energy requirements• Excellent line speeds

Solventless Laminating• Adhesives are expensive and relatively limited in

choice– Two-component urethane

• Residual monomer concerns • Extremely low initial bond strength and shear

strength– requires excellent tension control and balance

• Poor choice for autoclave applications - aliphatic systems

• Poor choice for extreme chemical resistance

Adhesive Lamination

Primary Web

Oven

Chill Roll

Secondary Web

Nip Roll

Finished Web Adhesive Deck

Adhesive Laminating

Adhesive Laminating

• Broad range of adhesive chemistry and performance options available– Acrylic– Polyether Urethane– Urethane– Polyester Urethane– Polyester

• Retained solvents• Adhesives are expensive

Solution Coating

Primary Web

Oven

Chill Roll

Finished Web Adhesive Deck

Solution Coating

• Much more versatile sealant choices than blown or cast films

• Breathable options available• Coatings are expensive

Extrusion Laminating

Die

Primary WebChill Roll

Finished Web

Secondary Web


• Extremely cost effective• Less expensive raw materials• High line speeds• High start-up costs


• Primers may be used to promote adhesion film and extrudate– Polyethylenimine (PEI)– EAA dispersion– Other chemistries similar to adhesives

• Extrudate may have multiple layers– Tie layers may be used to bond extrudate to

film or bond dissimilar materials within the extrudate

Extrusion Coating

Die

Primary WebChill Roll

Finished Web

Extrusion Coating

• Extremely cost effective• One less processing step• New resin combinations available• Coextrusion coating a powerful tool

– Avoids use of coextruded sealant films– Allows the use of inexpensive bulk layers– Allows barriers layers within extrudate– Allows the use of tie layers

Composite Structures


Heat Stable Layer

• Provides thermal and dimensional stabilityAllows the structure to be heat-sealed without sticking or stretching

Heat-Stable Layer

• Common Materials• Oriented polyester (oPET)

• Outstanding dimensional and thermal stability• Excellent tensile strength• Poor stress-flex resistance• Prone to dart tearing• Outstanding abrasion resistance• Used with a sealant web or coating (provides heat

sealability and improves stress-flex, pinhole, and dart-tear resistance)

Heat-Stable Layer

• Common Materials• Oriented polypropylene (OPP)

• Good dimensional and thermal stability (less than oPET)

• Not recommended for gamma or e-beam irradiation

• Excessive shrinkage in autoclave applications (as compared to PET)

Heat-Stable Layer

• Common Materials• Biaxially oriented nylon (BONY or OPA)

• Outstanding cut resistance• Excellent puncture resistance• Good stress-flex and pinhole resistance• Will cross-link and embrittle when irradiated• More expensive than oPET

Heat-Stable Layer

• Common Materials• Cast nylon (NY or PA)

• Outstanding durability• Outstanding stress-flex and pinhole resistance• Outstanding blunt puncture resistance• Difficult to cut• Will cross-link and embrittle when irradiated• More expensive than oPET

Heat-Stable Layer

• Common Materials• Paper

• Breathable, uncoated or with appropriate coatings• Thermally stable• Add bulk• Excellent printing surface• Particulate can be a concern

Heat-Stable Layer

• Common Materials• Tyvek

• Breathable, uncoated or with appropriate coatings• Outstanding strength• Outstanding durability• Outstanding tear resistance• Fair thermal stability• Fair dimensional stability


• Heat-Stable Layer• Barrier Layer

Barrier Layer

• Barrier Webs• Barrier Coatings

Barrier Layer

• Barrier Webs• Aluminum Foil

• 0.001” and above provides ultimate in barrier• < 0.001” pinholes may impact barrier

• EVOH• Excellent oxygen barrier• Humidity will significantly reduce barrier

• PCTFE (Aclar)• Excellent moisture barrier

• Polyacrylonitrile (Barex)• Good oxygen barrier

Barrier Layer

• Barrier Coatings• Polyvinylidene Chloride (PVdC)

• Good oxygen and moisture barrier• Contains chlorine

• Polyvinyl Alcohol (PVOH)• Excellent oxygen barrier• Moisture sensitive

• Aluminum metallization• Excellent oxygen and moisture barrier

• Silicon Oxide (SiOx) and Aluminum Oxide (Al2O3)• Excellent oxygen and moisture barrier

Barrier Layer


• Heat-Stable Layer• Barrier Layer• Bulk Layer

Bulk Layer

• Used to make the structure feel sturdier• Provides a cushioning effect when sealing• Inexpensive resins used

– LDPE most common


• Heat-Stable Layer• Barrier Layer• Bulk Layer• Sealant Layer

Sealant Layer

• Films– Weld Seal– Peelable Seal

• Heat Seal Coatings– Weld Seal– Peelable Seal

Sealant Layer

• Films– Polyethylenes:

Density (g/cc)Very Low Density Polyethylene (VLDPE) 0.890 - 0.915

Low Density Polyethylene (LDPE) 0.915 - 0.925

Medium Density Polyethylene (MDPE) 0.926 - 0.940

High Density Polyethylene (HDPE) 0.941 - up

Sealant Layer


As density increases (low to high)• Sealing temperature increases• Tensile strength increases• Stiffness increases• Hardness increases• Barrier properties increase• Chemical resistance increases

Sealant Layer


As density decreases (high to low)• Sealing range increases• Elongation increases• Stress-flex resistance increases• Elasticity increases• Impact strength increases

Sealant Layer


• Linear (e.g. LLDPE, LMDPE)

Sealant Layer


• Linear (e.g. LLDPE, LMDPE)• Higher melt points (15 - 25° higher)• Better chemical resistance• Better durability

• Impact strength• Puncture resistance

• Stronger seals (to itself)

Sealant Layer


• Metallocenes (e.g. mLLDPE, mPE)• Single site metallocene catalyst yields lower

molecular weight distribution than traditional multi-site catalyst

BC

D

A

A

A

Multi-site Catalyst

Single-site Catalyst

Sealant Layer


• Metallocenes (e.g. mLLDPE, mPE)• Low extractables• Lower seal initiation temperature• Better hot tack• Superior tensile strength• Higher elongation• Better durability

• Puncture• Impact

Sealant Layer

• Films– Polyethylenes Copolymers:

• Ethylene Vinyl Acetate (EVA)– Most range from 2% - 24% vinyl acetate– As VA content increases

» Sealing and softening temperature decrease» Impact strength increases» Flexibility increases» Stress-flex properties increase

– Less crystalline than equivalent LDPE– Less chemical resistance than LDPE

Sealant Layer

• Films– Polyethylene Copolymers:

• Ethylene-Methyl Acrylate (EMA)• Ethylene-Ethyl Acrylate (EEA)• Ethylene Acrylic Acid (EAA)

Sealant Layer

• Films– Ionomers (Surlyn)

• Low sealing temperature• High seal strength• Good hot tack• Ability to seal through contaminants• Good oil and grease resistance• Good impact strength• Good puncture resistance• Excellent formability

Sealant Layer

• Films– Ionomers (Surlyn)

Derived from ethylene-methacrylic acid copolymers

• Zinc cation– Best for product high in alcohol or water content– Provide adhesion to foil

• Sodium cation– Better hot tack– Better resistance to oil and grease

Sealant Layer

• Films– Polypropylene (CPP)

• Homopolymers– High melt point (Approx. 330°F)– Excellent temperature resistance– Used for autoclave sterilization– Good chemical resistance– More stiff and brittle than PE– Less crystalline than PE

Sealant Layer

• Films– Polypropylene (PP)

• Random Copolymers– Contain 1 - 5% ethylene molecules randomly inserted

into the polymer backbone– Lower melting point (approx. 300°F)– More flexible– Better impact resistance– Easier to heat seal than homopolymer PP– Better performance at cold temperatures than

homopolymer PP

Sealant Layer

• Films– Polypropylene (PP)

• Impact Copolymers– Contain elastomers like ethylene/propylene rubbers– Strong heat seal strength– More flexible– Better impact resistance

Sealant Layer

• Films– Amorphous Polyester (APET)

• Excellent chemical resistance• Chemically “clean”• High temperature resistance

– Dry heat sterilization

• Seals to polar materials

Sealant Layer

• Heat Seal Coatings– Vinyl Acetate (VA)– Ethylene Interpolymers– Polypropylene (PP)– Polyester (APET)– Ionomer (Surlyn)

Sealant Layer

• Seal Types– Weld Seals: Seal like materials together– Peelable Seals: Controlled incompatibities

between polymer materials

Bonding Agents• Adhesive• Primers• Tie Layers• Chemistry of Bonding Agent Dependent Upon:

– Type of material to be bonded– Product to be packaged– Type of package– Method of sterilization– Bond strength requirements– Elasticity of bond– Chemical resistance– Federal regulations– Environmental issues– Manufacturing equipment and process requirements

Making the Best Choice

• Product to be packaged• Type of sterile barrier system• Packaging equipment• Sterilization method• Width “sweet spot”• Volume

March 3-5, 2009www.healthpack.net

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optimizing cost and performance dhuanne dodrill · optimizing cost and performance dhuanne dodrill...

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