Plastic Applications

• High Density Polyethylene (HDPE)

  • Low cost
  • Easy processibility
  • Good moisture barrier
  • Low oxygen, hdyrocarbon, flavor barrier
  • Soft
  • Opacity/Translucent/Milky White Appearance
  • Blow molded bottles - food, medical, cosmetics, chemicals
  • Fluorination
  • Bags
  • Industrial packaging, dairy crates
  • Tubs (PP becomes brittle at low temperatures)
  • Screw Caps
• Low Density Polyethylene (LDPE)

  • Low cost
  • Easy processibility
  • Good moisture barrier
  • Low oxygen barrier
  • Lowest softening point - heat sealability
  • Elongation
  • Scuff resistance (soft)
  • Films and bags
  • Garbage bag
  • Shrink film
  • Sealing layer
  • Squeezable bottles
  • Snap-on closures
• Linear Low-Density Polyethylene (LLDPE)

  • Stretch film
• Metallocene Polyethylene (mPE)

  • Greater tensile
  • 10x dart impact
  • Produces better heat seals
  • High CoF
  • Difficult to process
  • Expensive
• Polypropylene (PP)

  • Isotactic PP - regular PP usually for Packaging
  • Atactic PP - gummy PP, adhesive base
  • Similar to PE in terms of some characteristics (barrier, cheap, easily processed, etc.)
  • Has higher softening point
  • Has better cold flow resistance
  • Has better clarity
  • UV-sensitive
  • Has excellent live hinge
  • Unoriented PP becomes brittle at low temperatures
  • CPP is sealable
  • OPP is not heat sealable
  • BOPP
  • Used as coatings to provide liquid holdout
  • PP film and bags
  • EBM
  • Injection molded and thermoformed (trays, tubs)
• Polystyrene (PS)

  • Ethylene + benzene = ethyl benzene, and then converted to styrene which is then polymerized to polystyrene
  • PS, EPS, HIPS, OPS
  • Optical properties are very good
  • Dimensional stability
  • Good printing
  • Good chemical against food
  • Poor barrier, physical strength, solvent resistance
  • Cosmetics, jewelry boxes
  • Thermoformed or injection molded
  • Clamshell
  • EPS - good insulation and cushioning
• Polyethylene Terephthalate (PET)

  • Condensation polymerization
  • Thermoplastic or thermoset
  • PET/PETE, OPET, PETG, rPET, aPET, CPET, VMPET
  • PETG- can be EBM'ed
  • PET resins are subject to hydrolytic breakdown
  • AA (acetaldehyde)
  • Highest tensile strength
  • Low elongation
  • High melting point
  • Excellent grease/oil barrier
  • Good printing characteristics
  • High use temperature, high impact strength, high scuff resistance
  • Dimensional stability
  • Not sealable
  • Generates static
  • Poor package openability
  • PET is more expensive than POF
• Polyvinyl Chloride (PVC)

  • PVC alone is brittle, hard, has low thermal stability, unusable
  • Additives are used
  • Plasticizers soften PVC
  • High impact strength, good scuff resistance, good dimensional stability
  • Excellent opticals
  • Sensitive to heat
  • Other properties change depending on the additives
  • Highly plasticized PVC have cling
  • Superior heat shrink properties
  • EBM bottles
  • Self-extinguishing
  • Blister shells
  • Targeted by environment groups
• Polyvinylidene Chloride (PVDC)

  • Expensive
  • Limited to films and coatings. It is not made into dimensional parts
  • Saran
  • Excellent moisture and gas barrier in a single material
• Polyvinyl Acetate (PVA/PVAC)

  • glue adhesive
  • if close to PVA, usually used as hot melt adhesive
• Ethylene-vinyl Acetate (EVA/EVAL)

  • copolymer of PVA and PE
  • If close to PE, LDPE properties, stretch wrapping
• Polyamide (PA)

  • Tough
  • Resist abrasion, puncturing, impact, cracking
  • Not heat sealable
  • Poor slip properties and water vapor barrier
  • Nylon
  • Condensing diamine and dibasic (nylon 66)
  • Polymerization of amino acids (nylon 6)
  • Way higher mechanical properties and oxygen barrier than nylon 6 or 66
  • Films, oriented
  • Unoriented nylon 6 - vacuum packaging of cheese and meat products
  • If nylon is oriented, it cannot be thermoformed (also true for PP)
  • Nylon used for abrasive products like coffee granules
  • MXD6 is used as an oxygen barrier layer in PET bottles for beer
• Polyvinyl Alcohol (PVAL/PVOH)

  • Water-soluble
  • Water soluble like pouches like in detergent products
  • Theoretically has the highest oxygen barrier, but because of its water soluble properties, it is impractical to use
• Ethylene acid copolymers and Ionomers

  • EEA - films, coatings, adhesive

  Ionomer (Surlyn)

  • best sealing layer that can seal through fats or oils
  • expensive
• Cellophane

  • is based on wood cellulose and not on petrochemicals
  • Superior dead fold properties and machinability
  • Generates lower static
  • Cost and performance cannot compete
• Epoxies

  • Adhesives and coatings
• Polycarbonate (PC)

  • made from carbonic acid and bisphenol-A (BPA)
  • Highest impact strength of packaging plastics
  • Returnable and large water bottles
  • High cost
• Polyacrylonitrile copolymer (PAN)

  • barex
  • only resin marketed for packaging purposes
  • offers excellent resistance to aggressive solvents
• Polyurethane (PU/PUR)

  • Foam in place
• Polyethylene Naphthalate (PEN)

  • Hot fill and retort applications
  • blocks out UV completely
  • has potential to replace glass in critical applications
  • very expensive
• Styrene-Butadiene

  • K-resin
  • Tough but soft, clear, easily processed
  • Poor gas barrier, UV sensitive, low resistance to solvents
• Polytetrafluoroethylene (PTFE)

  • Teflon
  • low coefficient of friction
  • Inert
  • used for packaging machinery
• Chlorotrifluoroethylene (CTFE)

  • Aclar
  • has the highest moisture barrier of packaging polymers
  • tolerate cryogenic temperatures and ionizing radiation
  • expensive
• Bioplastics

  • Polylactide (PLA)
  • Sometimes mistaken as PS
  • easily thermoformed at low temperatures
• Thermoset plastics

  • phenol-formaldehyde and urea-formaldehyde
  • very good for solvent resistance
  • used for specialty closures and applications
  • doesn't develop sink marks
• ABS- acrylonitrile-butadiene-styrene

  • tough, high impact
  • polyacetals, polysulfones
• PVA is usually used for adhesives like sticks for glue gun