Page 27 - Plastcs News August 2017

FEATurES

A carbon footprint is historically defined as the total set and formed into the desired bottles. This final process
of greenhouse gas emissions caused by an individual, represents about eight percent of a plastic bottle's carbon
event, organisation, or product, expressed as carbon footprint. Given that production of plastic resin is usually
dioxide equivalent. In most cases, the total carbon the major contributor to the carbon footprint of a plastic
footprint cannot be exactly calculated because of bottle, recycling can reduce the carbon dioxide and other
inadequate knowledge of and data about the complex greenhouse gasses by an estimated 30 to 70 percent.
interactions between contributing processes, especially
which including the influence on natural processes storing For practical purposes, recycled PET (washed flakes from
or releasing carbon dioxide. For this reason, Wright, post-consumer PET bottles) can be used for making any of
Kemp, and Williams, have suggested to define the carbon the following products.- Fiber Fill FF, Spinnminf Fiber, PoY,
footprint as: A measure of the total amount of carbon Sheet, Non Woven, Monofilament, Masterbatch,Straps,
dioxide (CO2) and methane (CH4) emissions of a defined Bottle
population, system or activity, considering all relevant Fiber fill denotes applications where short fibers are used
sources, sinks and storage within the spatial and temporal to fill cushions, pillows etc.
boundary of the population, system or activity of interest.
Calculated as carbon dioxide equivalent using the relevant Polyester Staple Fiber (PSF) is further used in making a
100-year global warming potential (GWP100). wide range of fabrics (clothing, upholstery etc.)
The Pacific Institute, US based non-profit research PoY (partially oriented yarn) is another type of polyester

organization, estimates that the energy used in the yarn that is used to produce texurized yarn that goes
production and use of plastic bottles, such as water bottles, into making fabrics. Even though all these products are
is equivalent to filling the plastic bottles one-quarter feasible from recycled PET, there are some technical issues
full with oil. oil affects global warming by producing that dictate the use pattern. The washed flakes typically
high quantities of greenhouse gases when it is burned. have an internal viscosity (IV) in the range of 0.6-0.75.
The manufacture of one pound of PET -- polyethylene PET used for making bottles, sheets, masterbatch etc.,
terephthalate -- plastic can produce up to three pounds of has to have a higher IV. This gap (in IV of washed flakes
carbon dioxide. Processing plastic resins and transporting and bottles) can be bridged by subjecting the washed
plastic bottles are major contributors to a bottle's flakes to an additional step (of solid state polymerization,
carbon footprint. The Beverage Industry Environmental which increases the molecular weight of the polymer and
Roundtable estimates that one 500-milliliter (0.53 quarts) hence the IV of the resulting material). This involves an
plastic bottle of water has a total carbon footprint equal additional cost.
to 82.8 grams (about 3 ounces) of carbon dioxide. In India, washed flakes are typically (95% of all washed

As we know Energy is needed to convert the plastic flakes) used to make POY, FF, PSF, sheets, non-woven.
resin into plastic bottles. Plastic resin, such as PET resin,
is melted and injected into a mold, and then heated

27 Aug ust 2017 | Plastics News