Biodegradable Plastics: a pragmatic comparison Jim Cairns, EPAS/Environmental Plastics Advisory Services

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Biodegradable Plasticsa pragmatic
comparisonJim Cairns, EPAS/Environmental
Plastics Advisory Services

• 31st Annual RCBC Conference
• Harrison Hot Springs
• June 2, 2005

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Disclaimer

• This is not a sales pitch for
• any specific class of plastic

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EPAS Position

• Responsibly managed, plastics are
• more part of the solution than the problem.

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Degradability of plastics

• Virtually all plastics degradable
• Rate of degradation may be adjusted
• Cost / performance governs selection

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History of biodegradable plastics

• Not a new class of plastics
• Have been around for about 20 years
• Over a decade ago took a nasty knock
• Starch added to conventional plastic was promoted
  as way to go
• Proven to be ineffective, tainted plastics image!
  

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Renewed interest

• Continued growing public awareness
• Potential application to high-volume organic
  discard stream
• Industry giants enter Dupont, Cargill-Dow, BASF,
  Eastman, Proctor Gamble, Novamont,
  Polargruppen.
• Recognize need for performance certification to
  avoid repetition of starch disaster

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Two major types

• Biodegradable Plastics (Bios)
• Made from agricultural sources or fossil fuel
  sources
• One-step bio-degradation
• Oxo-biodegradable Plastics (Oxos)
• Made from conventional fossil fuel sources
• Modified with additives for controlled life
• Two-steps disintegration, then biodegradation

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The Bios overview

• Agricultural sources
• corn -gt starch -gt sugars -gt polyactide polymer
  plastic (PLA)
• Petrochemical sources
• Certain monomers will de-polymerize when wet,
  becoming acids and alcohols which are composted
  by bacterial action
• Higher cost, possibly lower physical performance,
  than conventional or Oxo plastics

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The Bios agricultural sources
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Agricultural Bios closed-loop
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The Bios certification

• Producers represented by Biodegradable Products
  Institute ( BPI) (www.BPIworld.org)
• Meet standards established to assure performance,
  credibility (ASTM 6400, ASTM 6868, EN 13432)
• Completely mineralize to water and carbon dioxide
  under controlled conditions
• BPI members include industry giants (BASF,
  DuPont, etc.)
• Dow has withdrawn from Cargill Dow . Eastman
  has sold Eastar its co-polyester to Novamont

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The Oxos overview

• Petrochemical based plastics
• Modified by use of proprietary chain breakers
  (e.g. TDPATM - Totally Degradable Plastics
  Additive)
• Designed for a controlled lifetime
• Disintegrate then degrade when in adequate
  composting environment
• Less extra financial cost than BPI products

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The Oxos

• Represented by Oxo-biodegradable Plastics
  Institute (OPI) (www.oxobio.org)
• Meet safety and performance standard (ASTM
  D6954-04)
• Disintegrate , may or may not compost, no third
  party pass / fail certification
• OPI membership small relative to BPI.

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Differentiation of ASTM standards

• ASTM 6400/ 6868 EN 13432 (Bios)
• Pass/fail tests for compostability
• Must achieve 60 biodegradation within 180 days
  in specified composting conditions
• certified by third party testing
• ASTM 6954 04 (Oxos)
• A standard testing guide
• Recognizes oxo-biodegradability as a two step
  process
• Disintegration (oxidation) and subsequent
  bio-degradation to compost

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Independent Oxos

• Not represented by OPI
• Also offer controlled life plastic products
• May or may not meet ASTM standards

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Biodegradable plastics markets

• Collection bags for Source-Separated Organics
  (SSO)
• Convenience packaging (paper/plastic, deli,
  blister)
• Disposable cutlery / dishes
• Six pack retention rings

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Biodegradable plastics Potential Benefits

• SSO collection bags avoid negative cosmetic
  impact on composts value
• Disposable products/packaging convenience of
  composting along with organic food residues

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Factors for ConsiderationBio, Oxo, or
conventional?

• Performance (weight / strength)?
• Relative Cost?
• Environmental impacts of ag-based plastic?
• How effectively will Bios / Oxos compost in
  wide variety of composting conditions?
• Potential impacts of Bios/ Oxos on mechanical
  recycling of conventional plastics?
• Potential impacts of Oxo additive residues?

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Environmental Impacts?

• Agricultural expansion (to grow more grain for
  human, animal, bio-fuels, MTBE replacement)?
• Compost value of bios / oxos versus energy
  value of exhausted conventional plastics?
• Might Bios / Oxos promote littering?

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Conclusions

• Many as yet unknown factors.
• Bios and Oxos will enjoy niche markets.
• They may create as many problems as they resolve.
• They are not a panacea.

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The constructive dialogue continues