17.5% of the rigid and film plastic consumed in Brazil returns to production as raw material, or roughly 200,000 tonnes per year.

Of this, 60% comes from industrial residue and 40% from urban refuse, according to estimates by the ABREMPLAST (Brazilian Association of Plastic Recyclers).

Lightweight, resistant and practical, rigid plastic composes around 77% of plastic packaging in Brazil, such as soda bottles, recipients for household cleaning and hygiene products and food pots. It is also the basic raw material in drums, textile fibers, tubes and connections, shoes, household electronics, in addition to buckets, household utensils and other products. Brazil consumes 3.9 million tonnes of plastic per year. Of these, approximately 40% has a short life-cycle. The plastic can be reprocessed, generating new plastic ware and energy.

The weight varies from city to city. In Rio de Janeiro, for example, plastic in general accounts for between 5% and 7% of refuse, in Curitiba, 6%.

The Englishman Alexander Parkes produced the first plastic in 1862. Durability and lightweight, plastic quickly became one of the greatest phenomena of the industrial age. However, as most of it was not biodegradable, it also became the target of criticism from environmentalists. Recycling, begun by the plastics industry itself to make up for losses in production, has contributed to reducing the impact on landfills. In addition to the environmental question, in economic terms the waste cannot be justified: by using recycled plastic, energy savings of up to 50% are possible.

Variety of Plastic Resins

There are seven different families of plastics, which are often chemically mutually incompatible. In other words, the mixture of some types could result in defective low-quality material, without the technical specifications needed for its return to production as raw material. The most common rigid plastics on the Brazilian market are:

a) Polyethylene terephthalate (PET), used in soda pop bottles.

b) high-density polyethylene (HDPE), consumed by manufacturers of crates for drinks, buckets, drums, auto parts and other products.

c) Polyvinyl chloride (PVC), common in tubes and connections, and bottles for mineral water and liquid detergents.

d) Polypropylene (PP), used in packaging for pasta and biscuits, margarine tubs, household utensils, among others.

e) Polystyrene (PS), used in the manufacture of household electronics and disposable cups. Cempre has publications available that facilitate the identification of each of these resins.

STRICT SPECIFICATIONS FOR THE MATERIAL

The various kinds of polymers need to be identified and separated for recycling. Some resins are easily identified visually. However, in most cases selection is made by observation of the color of the flame or smoke and the odor whilst being burnt. Standardized symbols used by the manufacturers facilitate the identification of the packaging. (See codification leaflet - Cempre).

CONTAMINATION

The principal contaminants of rigid plastic are fats, organic remains, metallic handles, staples and labels. Impurities of this nature reduce the selling price and require more care in washing before processing. The quality of the material depends on the source of separation: plastic that comes from curbside collection is cleaner than that separated at plants or from dumps. Due to these barriers, recycled plastic is not normally used in packaging that is in direct contact with food or medicine, nor toys or safety parts that require certain technical specifications.

Reduction at source

Over the last 20 years, the average weight of plastic packaging has decreased by around 50%, reducing the impact of its disposal in landfills. With the production of more durable and better quality plastic, re-utilization of used packaging has increased.

Composting

Rigid plastic cannot be used in composting.

Incineration

Plastic is highly combustible, with a calorific value of 18,700 BTUs per kilo, in the case of polyethylene – higher than coal and close to that of fuel oil.

Landfill

Its decomposition in landfills is slow and difficult. One answer, which still does not completely resolve the problem, has been to invest in research into biodegradable plastics, which for the time being are much more expensive than petrochemical resins.

Back to the origins

After being separated, baled and stored, the plastic is milled and washed before returning to industrial processing. After drying, the material is transferred to the agglutinator, shaped like a cylinder, containing rotor blades that spin at high speed and heat the material by friction, turning it into a plastic paste. A small amount of water is then added to cause a sudden cooling, making the molecules contract, increasing its density. The plastic is now in the form of granules and is sent to the structure machine that melts and gives a homogenous appearance to the material, which is then transformed into spaghetti-like strips. In the final stage, the strips of melted material go through a cooling bath, turning them into solids. After being shredded into pellets, these are sold to plastic ware manufacturers, who may mix the recycled material with virgin resin to produce new packaging, parts and utensils. I00% of the material can be used.