Manufacture of paper

Paper is made up of millions of lint, which come from plants, which we call FIBERS. Currently, most papers are made from the trunk of trees cultivated.

Brazil produces pulp and paper exclusively from forests planted with eucalyptus and pin us.

In 1840, a German named Keller had the idea of ​​grinding the wood in a mill to extract the fiber. This produced the first pulp of wood. The has made great strides since then, especially in recent years. The five main phases of paper making, however, remain unchanged:

Manufacture of paper

Chip Cutting

Eucalyptus, at age 7, is ready to be cut. After cutting, the logs are peeled and chopped into chips. The bark is recovered and used, such as fuels, to produce steam and electricity

Pulp Manufacturing

The wood is made mainly of cellulosic fibres adhered to each other with a "glue" called lignin. To convert wood to pulp, lignin needs to be removed. The most common processes are:

• Mechanical process: The pulp is obtained by milling the trunks with water and steam. This type of pulp is used to, for example, produce newsprint.

• Chemical Process: Usually called the "KRAFT" process, which in German it means "STRONG". In this process, the chips are mixed with and high-pressure cookers in huge pressure vessels called digesters. The combined action of chemicals and heat dissolves the lignin and separates it from the fiber. Papers made of chemical pulp are very strong. They are used, for example, to make bags of stores and supermarkets.

Bleaching
For the manufacture of certain types of paper, the pulp must be bleached. For this, chemicals that dissolve or eliminate lignin (natural of fibers). The resulting pulp is not only whiter, but also has a tendency to yellow over time.

Sheet formation

When the pulp reaches the inbox of the paper machine, its water ratio is 97%. The mixture is poured in the form of a fine, uniform jet a movable screen called the forming screen. The filtering action of this forming screen, combined with a vacuum system, extracts most of the water contained in the forming a sheet of paper. The sheet is pressed between rollers to remove more water and then passes through the drying section where it comes in contact with cylinders are usually heated with steam, extracting most of the remaining water by evaporation. At the end of the machine, the paper is rolled in rollers, which are rewound and segmented into smaller rollers, following to the conversion or finishing section.

Finishing

It is the step of cutting, packaging and packaging the paper. The bobbins are cut on A4 sheets, etc. depending on the use that will be made of the paper.