MINERAL REINFORCED COMPOUNDS FORCOMPOSTABLE FILM EXTRUSIONSPE FlexPack ConferenceHouston, TXMarch 1, 2011

Frank A. RuizPresident, Plastimin LLCResearch Consultant, Heritage Plastics, Inc.P.O. Box 271769Flower Mound, TX 75027FrankRuiz@att.net

Development of Film Extrusion Compounds for Packaging Applications

Identify cost requirements

Define critical end-product parameters Mechanical, Optical, Barrier

Evaluate processing requirements vis-à-vis current equipment

Compostable Product Development Impetus

Volume of Solid Waste Generated in U.S. Increasing 70 MM Tons in 1960 229 MM Tons in 2001

Number of Landfills in U.S. is decreasing 7924 in 1988 1858 in 2001 (-77% in 13 years, mostly smaller

operations) Virtually impossible to site new landfills

(NIMBY) Incineration resisted in many areas Recycling rates have been difficult to increase

An Enormous Potential Resource

Limited Composting Done Today

Woodhue Compost Testing

Final Screening at Woodhue

WHAT IS COMPOSTING?A process using thermophilic (heat-loving) bacteria that are naturally-occurring in organic waste

Bacteria grow and consume raw materials under the proper conditions:

High heat (136 – 158 deg F)MoistureOxygenOrganic raw materials

High heat “sterilizes” waste by killing pathogenic bacteria (i.e., the ones that make us sick)

COMPOSTING: WHAT & WHYCompost microorganisms “eat” just about anything organic:

•Yard Waste•Wood trimmings•Food Waste•Carrion/Road Kill•Paper & Waxed (not PE-coated) Linerboard

Compost end product is a valuable soil nutrient and augmentationNew composting facilities opening in US

Encouraged by EPA as a method of landfill diversionRequires less physical “footprint” than landfillNew operation in Brooklyn, NY!

Product Development Impetus

First Major Compostable Film Opportunity:

Develop compostable bags and can liners for:

Organic Waste diversion from grocery stores & restaurants

Yard Waste collection by municipal & private waste haulers destined for composting

Product Development Requirements

Product MUST meet ASTM D 6400: Specification for Compostable Plastics

ASTM D 6400 requires: 90% mineralization to H2O & CO2 in 180

days Fragmentation: 90% to < 2.0 mm Ecologically non-toxic when measured

using ASTM D 6002 or OECD Guideline 208

PE “oxo-degradable” bags after 60 days

Development of Compounds for Trash Bag & Can Liners Commodity Market; Cost Critical;

competition is cheap labor Need high puncture, tear, &

tensile strength combined with high ductility

Clarity not critical (translucent) Not require drying Process on current equipment

Same extruder screw, die, air ring Able to print, heat seal, slit…

Commercially-Available Compostable Resins in N.A. Aromatic/Aliphatic Co-polyester

Easy to extrude, no need to dry Film extremely elastic

Plasticized Starch Blend Easy to extrude, moisture level critical, very

rapid biodegradation Poly-Lactic Acid

VERY moisture sensitive Not suitable by itself for film extrusion &

conversion PHA

Film extrusion difficult without modification

Aliphatic-Aromatic Co-Polyester(A-A copolyester)

Readily available in US from BASF as Ecoflex™ Suppliers of similar grades in Asia not

exporting to N.A.

Does not require drying prior to extrusion

BASF dedicated to the growth of the Market Technical and Marketing Support

Plasticized Starch Blends

Available in US from Novamont Partially based on renewable

resources Require a specific moisture level for

extrusion Novamont helped pioneer and is

dedicated to the growth of the Market

PolyLactic Acid (PLA)

Readily available in US from NatureWorks LLC

Based on renewable resources Moisture Sensitive NatureWorks very dedicated to the

growth of the market Technical and Marketing Support

PolyHydroxy Alkanoates (PHA, PHB)

Available commercially from Telles & Tianen Biologic

Based on renewable resources Telles has started a 50KT/yr. plant in

Clinton, IA Dedicated to the growth of the Market Technical and Marketing Support

* Telles is a J.V. between Metabolix and A.D.M.

Processing Characteristics of Compostable Polymers

Drying of PLA required before extrusion to prevent breakdown to lactic acid

Most co-polyesters also must be dried (except BASF Ecoflex™)

PHA does not require drying except for HT extrusion

Starch blends require proper moisture level for extrusion

Physical Properties of Compostable Polymers

Physical properties Co-polyesters very elastic PLA very rigid PHA rigid to flexible; crystalline surface Modified starch a range of properties Blends offer a range of properties

Temperature Resistance PLA heat resistance – new grades available Co-polyesters poor heat resistance PHA higher heat resistance (MP = 180° C).

COMPOSTABLE PACKAGINGAPPLICATION DEVELOPMENT PROCESS

Market is growing rapidly (50%/yr) as more institutions initiate organic waste diversion (airports, malls, stadiums, office buildings, golf courses)

Base product on compostable polymers Blend polymers and mineral(s) to

achieve desired end-use properties Utilize low levels of additives if

necessary to improve processing without sacrificing D 6400 Certification

Product Development Strategy

Formulate polymer blends to achieve intermediate properties, processability

Utilize Heritage Plastics polymer mineral reinforcement technology to modify co-polyester film properties Increase Stiffness Improve Productivity, Convertability Improve Bag Aesthetics Reduce Cost

Any additives must not interfere with composting process

All ingredients must have no potential for bioaccumulation or plant uptake

Product Development Synergy

Test compounded blends at Heritage Bag Company Utilize film extrusion & conversion

expertise Support desire to enter market

Adapt rate of degradation Rapid for organic waste diversion Slower for fresh-cut grass and yard

trimmings Result: Compounded blends of

Biodegradable polymers & either talc or calcium carbonate

Compostable Product DevelopmentBench-Scale Compost Testing – Atlanta, GA

Compostable Product DevelopmentBench-Scale Compost Testing

Development of Compounds for Compostable Film Extrusion

Work to date has yielded two commercial compostable film extrusion grades:

Compound A: A-A-copolyester, poly-lactic acid, talc (Biotuf™ 970)

Compound B: A-A-copolyester, poly-hydroxyalkanoate, & calcium carbonate (Biotuf™ 978)

Development of Compounds for Compostable Film Extrusion

Compound A: A-A-copolyester base poly-lactic acid added to increase

stiffness talc added to increase stiffness, bubble

stability, film antiblocking, reduce cost 2500ppm slip

Development of Compounds for Compostable Film Extrusion

Compound B: A-A-copolyester base poly-hydroxyalkanoate for stiffness,

mineralization rate increase, bio-based content

calcium carbonate to increase bubble stability, film antiblocking, reduce cost

Developed in partnership with Telles/Metabolix

Extrusion of Compostable Film Compounds

Melt temperatures 160 – 180 ° C (320 – 360° F) Cooler than LLDPE or HMW-HDPE, similar to LDPE PHA begins to thermally decompose > 180° C

Minimize shear and residence time (PHA) Resins & Compounds are Polar:

Effective “purge” agents Higher tendency to stick to metal (i.e. screw root) Conventional PE slip agents less effective

Purge & start up line with 2 – 4 MI LDPE to minimize scrap

Processing of Compostable Resins

Extruder Type * 65mm GF 65mm GF 65mm GF

Extruder RPM 70 70 70

Die Size, mm 225 225 225

Die Gap, mm 1.5 1.5 1.5

Melt Temp °C (°F)

216 (420) 160 (320) 170 (340)

Output Rate, kg/ hr. (lb.hr)

218 (480) 180 (396) 170 (374)

Blown Film Extrusionof Compostable Compounds

Extruder = 65 mm grooved-feed, 24/1 L/D GP dual purpose screw (LLD & HMW-

HDPE) Die = 225 mm Die gap = 1.5 mm Compound A extensional rheology

(bubble) similar to LDPE Compound B extensional rheology

(bubble) similar to LLDPE (run “In the Pocket”)

Extrusion of Compostable ResinsCompound A B

Extruder Profile:

Barrel Profile, °F 280/290/300/300 340/320/300/300

Adapter/Die, °F 320/320 340/340

Process Conditions:

Extruder RPM 70 70

Head Pressure, psi 3400 3200

Melt Temp °C (°F) 160 (320) 170 (340)

Output Rate, kg/ hr. (lb.hr) 180 (396) 170 (374)

Co-PET/PLA/TalcCompostable Compound Extrusion

Co-PET/PHA/CaCO3Compostable Compound Extrusion

Properties of Compostable Films

Compound Type Compound A Compound B C-6 LLDPE

Film Thickness, mils

1.2 1.2 1.2

Dart Impact, g 350 240 280

Elmendorf Tear, g MD 320 250 280

TD 180 700 480

Properties of Compostable Films

Compound Type Compound A Compound B C-6 LLDPE

Film Thickness, mils

1.2 1.2 1.2

Tensile Strength @ yield, psi

MD 2000 No defined yield

1500

TD 2100 1700 1600

Tensile Strength @ break, psi,

MD 4500 4000 5500

TD 3800 3280 4500

Compostable Product Certification

Films biodegrade >90% in <180 days Films satisfy the requirements of ASTM

D6400–04: Standard Specification for Compostable Plastics: Compound A at 3 mils and below Compound B at 14 mils and below

Certified by BPI

Compound B @ 0.25 mm Hot Composting Test at OWS

Jan. 08, 2010 XS

Compound B @ 0.35 mm Hot Composting Test at OWS

Jan. 08, 2010 XS

Advantages of Compostable Bags and Liners

Certification by Biodegradable Products Institute required for Composter evaluation (not acceptance!)

Allows Pre- and post-consumer food waste diversion with minimal health hazard and odor

Provide tear and puncture resistance similar to PE products in use

Lifting strength and load capacity necessary for wet refuse

• Environmental• Higher renewable materials content • Faster Composting (More rapid mineralization)

• Reduce resistance to film at compost facilities• (Not for fresh cut grass)

• Greater D6400 maximum thickness Rating 0.35mm• Potential Bio-Energy Production - Anaerobic Digestion

with sufficient PHA content

•Logistical• Domestically-sourced material (Telles)• Non-petroleum Feedstock ($ stability)

Characteristics of PHA containing compostable compound

Characteristics of PHA containing compostable compound

Film Properties Commercial Film Processing Rates Excellent Dart and Tear strength MD strain hardening yields high load capacity Bag Shelf Life approximately 12 mos.

Summary Compounded blends of available compostable

polymers yields compostable film formulations Mineral addition improves product performance and

lowers cost Proper ratios of resins and minerals key to

obtaining desired processing characteristics and end product properties Different compounds may require equipment

modifications to equipment configuration and/or process conditions

Look to supplier for guidance More commercial composting = more

opportunity for compostable packaging Will require labeling & consumer education