Packaging: Plastics

Environmental concerns about EPS

- EPS has been targeted by environmental groups (litter problems with disposal) - numerous attempts to ban usage of EPS food services items in certain states. (mcdonalds clam shell) - few good recycle opportunities

#5: Polypropylene (PP)

- Less dense than PE, and stiffer - Excellent clarity and sparkle - clear or colored - high temp tolerance for hot fills (oven wraps on paperboard cartons. Closure-plastic cups.) Squeezable ketchup bottles: - initial bottle 9 layers of plastic - grew market share, using this plastic bottle would be more expensive than glass - solved a consumer pinch point (tough to get ketchup out of glass bottle) - common structure for chips and pretzels - often a thin layer of aluminum is added to improve barrier - metalized PP

#6: Polystyrene (PS)

- clear food service - foamed expanded material EPS (egg cartons, shaped cushions and packaging materials, foam labels, single use cup trays and plates, clear film)

Application of plastics

- plastics have replaced many metal, glass, paper, and woods packaging. - today, more than 200 million tons of plastic are made each year - the U.S. produces more plastic than steel, aluminum, and copper combined. - plastic encapsulates medicines, ensure sterile surgeries and provide artificial organs and limbs - plastics found in alarm clocks, shower curtains, contact lenses, cell phones, cookware, furniture - even the statue of liberty is coated in a polymer that protects it from corrosion

Major plastics

- polyethylene (PE): LDPE and HDPE - polypropylene (PP) - polyethylene terepthalate (PET) - polystyrene (PS) - polyvinyl chloride (PVC)

many plastics can be easily identified by common names such as...

- teflon - rayon - nylon - velcro - lycra - polar fleece

#3: Polyvinyl Chloride (PVC)

- tough film - excellent clarity-sparkle - non-food, shampoo bottles - thermoformed blisters and clamshells - Food: low O2 barrier-film for red meats, cling wrap - negative influences: almost obsolete in the U.S. for bottle food/beverage. Losing market share to PET.

Plastics History

1843: sap with resin from rubber trees (local population made tool handles, etc.) 1845: cellulose nitrate to replace ivory (billiard balls, first commercial synthetic polymer) 1933: polyethylene (waterproofing electronics in 1930, significant early application was with waterproofing wires for radar and sonar during WWII)

#1: Polyethylene terephthalate (PET)

Characteristics: - excellent clarity/transparency-sparkle (clear or colored) - good tensile strength - can resist internal pressure from carbonizations - all soda bottles up to 3 liters - fair gas barrier

#4: LDPE

Most widely used plastic in packaging. - flexible - transparent - tough and shock resistant - is not soluble: can be used with solvents, relatively inert chemically - moisture resistant, low water vapor permeability - poor barrier to vapors, oil, oxygen, CO2 - low cost - commonly used for bags - bottles - films - bags - closures - pallet stretch wrap for load stabilization - coated or coextruded with other substrates

Raw materials for plastic

Naptha is the primary raw material used to produce synthetic polymers and is derived from petroleum. Natural gas is the second most common raw material. Petrochemicals are produced from these raw materials which are used in the polymerization reactions. Bio-based materials.

#2: high density polyeythylene

The polyethylene family is the most widely used type of plastic. - more dense than LDPE (more mass in less valume) - HDPE is generally more expensive than LDPE - may be clear like LDPE, but often has a translucent, whitem milky appearance. - formed by extrusion molding or thermoforming - typical application: cups, tubs, and bottles - biggest uses is as plastic jugs for milk, fruit juices, and waters

Polymers vs polymers

among naturally occurring polymers are proteins, starches, cellulose, and latex. Synthetic polymers are produced commercially on a very large scale and have a wide range of properties and uses. The materials commonly called plastics are usually synthetic polymers.

thermoset

materials harden when heated or in some cases when they are treated with certain chemicals

thermoplastic

materials soften when heated and hardened again when cooled. This process can be repeated indefinitely

plastic packaging

packaging is the largest market for plastics. More than a third of the major thermoplastics used in the U.S. are used for packaging. Plastic is the fastest growing category in packaging.

Raw material process

petrochemicals, polymerization, plastic, product

definition of plastics

plastics are based on synthetic resins or modified polymers of natural origins.

Soft drinking bottling

soft drink bottlers switched from aluminum and glass to plastic because of: - lower weight - variety of shapes and sizes - less damage and breakage - transparent reduced shelf life of beverages in plastic containers: - 6-8 weeks in PET versus months to a year in glass. - necessary to restructure the entire supply chain to accommodate the change. - drives the need for numerous small bottlers across the country.

Plastics are ______ in the finished state, but can be molded using controlled ____ and _______ at relatively _____ temperatures, compared to glass and metals

solid, heat, pressure, low

growth of plastic packaging

the growth of plastic packaging has accelerated rapidly since the 1970s, largely because of four characteristics of plastics: - low density = weight savings--lower costs of transport - formability: easy to form into shapes (soft or rigid, solid or foam, thin or thick, sheet or film) - strength and damage resistance: lightweight but strong, high resistance to weight ratio. Damage resistance, flexibility. Chemical resistant (relatively inert, no corrosion) - economics: containers generally less expensive than glass or metal. Transportation cost savings. Lower liability claims, damage. Flexibility into and out of market quickly. Can be produced on site where filling occurs.

Plastics are classified into two categories according to their behavior after being molded into the desired shape

thermoplastic and thermosets