71% of the overall volume of corrugated cardboard consumed in Brazil is recycled. In the American market, corrugated cases have a 21% content of recycled paper. Many cases have a brown color in their layers. Some of them, however, utilize a white layer, known as "mottled white", made up by white office paper recycled.

The value of corrugated cardboard varies a lot according to the region and the preparation of the material after being separated from the waste.

Many Countries encourage paper recycling, stimulating the installation of depuration plants that are able to start the processing and furnish bales of secondary cellulose to be used in any paper factory whatsoever, which is not required to have a special equipment to prepare the pulp from the parings. In Brazil, there are no such initiatives.

The material is easy to collect in large commercial volumes, being easily identified when blended with other sorts of paper. Thus, its processing cost is relatively low.

Corrugated cardboard is used primarily in cases for the transportation of products to factories, warehouses, offices and households. Usually called paperboard, though the term is not technically correct, that material has a middle layer between its outer layers, undulated, in the shape of an accordion.

Brazil has recycled 1.6 million tons of corrugated paper per year. The National production of paper in 1999 was 6 million tons.

In São Paulo, paper and paperboard - including corrugated cardboard - correspond to 18.8% of the waste. In the United States, in 1997, corrugated cardboard constituted 12,2% of the weight of the urban waste before recycling, totaling 23.9 million tons.

The recycling of secondary fibers is as old as the discovery of paper itself, in the year 105. Since that time, used paper may be reconverted in pulp to generate low quality products, such as the core of paperboard boxes, cards and packaging paper.

orrugated cases have been recycled by large package manufacturers for a long time. That demand produced a volume of paper that is sufficient to justify the investment in equipment to prepare the material to be negotiated with paper scrap collectors.

As the interest in recycling increased, the amount of cases made with the recycled material also increased - one ton of paper parings may prevent the chopping of 10 to 12 trees in reforested commercial plantations. And the manufacture of paper with the use of parings wastes 10 to 50 times less water than the traditional process, which utilizes virgin cellulose, besides reducing the energy consumption in 50%.

CONTAMINATION

The products that contaminate paper are wax, plastic, oil stains, soil, wood splinters, strings, ropes, metal, glass, among others. An equally limiting factor is the blend with the so-called yellow corrugated case, made up by recycled fibers that have lost their original resistance. The contaminant materials cannot exceed 1% of the volume and the total loss in reprocessing may not exceed 5%. The excess of dampness changes the paper features, causing its recycling to be difficult.

STRICT RAW MATERIAL SPECIFICATIONS

The paints used in the manufacture of cardboard may technically cause its recycling to be unfeasible. The same thing takes place if the corrugated cardboard has undergone an anti-dampness treatment with resins non-soluble in water. The output of the recycling process depends on the material pre-processing - separation, cleaning, pressing - performed by the parings collector.

Reduction at source

Corrugated cardboard cases usually don't weigh too much. In the last 10 years, manufacturers got to reduce the weight between 10% and 15%. The need to make compression, piling, and rupture tests to ensure the material's resistance limits their ability to reduce the weight. The use of recycled fibers in a larger quantity may increase the weight of corrugated cardboard cases, causing them to be more resistant.

Composting

If it is adequately cut, corrugated cardboard is easily decomposed. Blended with other residues, it becomes a source of nitrogen to the microorganisms.

Incineration

The material is easily flammable, with a 7.047 BTUs per kilogram heating power, compared to the 4.500 BTUs of the urban waste as a whole.

Landfills

The material degrades slowly in landfills.

Back to the origins

Forwarded by paper collectors to the paper industries, the material is disaggregated in the "hidrapulper", a sort of giant blender that separates the fibers, turning them into a homogenous mixture. Then, by means of screens, impurities such as adhesive tapes and metals are removed.

In the case of corrugated cardboard, opposite to the office paper's, there is no need to apply techniques of thorough cleaning, paint removal, bleaching or special washes.

With the best quality fibers one manufactures the paper cover placed on the outer surface of the cardboard. The low quality ones are used in the manufacture of the lining for the inner surface of the cases. And the lowest quality ones are used to produce the corrugated middle layer, by means of a machine called "corrugator".