Manufacturing Recycled Paper

Manufacturing recycled papers involves a multi stage process that starts with the raw material of waste paper and ends with the final product of a recycled paper that is comparable with virgin fibre papers both technically, aesthetically and on press.

Recycled paper can either be manufactured ‘in-line’ (pulp and paper produced in one process) or recycled pulp can be produced and transported to a paper mill for paper production. For this example we have shown the ‘in-line’ process:

• Raw Materials
• Pulping
• Screening
• De-inking
• Whitening
• Pulp Preparation
• Wet Section
• Pulp Transformation
• Drying
• Coating
• Drying
• Jumbo Reel
• Final Coating

Raw materials

The main raw material used to manufacture recycled paper is waste paper. We use post-consumer waste paper which means it has been used by the customer for its final use. It takes approximately 1.2 tonnes of waste paper to produce 1 tonne of recycled paper. It would take around 2.5 tonnes of wood to produce the equivalent virgin fibre paper.

*based on Cocoon

Pulping

Sorted waste paper is dispersed in water in the pulper to separate fibres, ink and other components.­

*based on Greenfield

Screening

Cyclonic purification allows for complete elimination of all contaminants and non fibrous materials such as:

• Minerals
• Plastics
• Staples
• Dirts

In addition, 99% of ink and glue is removed from the pulp during this process whilst preserving cellulose fibre quality.

De-inking

Ink is extracted from the pulp mix through flotation. Air is blown into the bottom of the tank with soap which creates bubbles; the ‘hydrophobic’ ink particles stick to bubbles that float to the surface, the ink is then skimmed from the surface. 90% of the residue produced by this process is put to agricultural use (composting and spreading), or used as a raw material to produce cement and bricks.

Whitening

Our recycled pulp is producedwithout the use of chlorine; a Process Chlorine Free (PCF) method.

The whitening process uses bio degradable cleaners. Colour is removed from the fibres using sodium hydrosulphate, a reductive bleach. Hydrogen peroxide is used to brighten the fibres and when disposed of it breaks down into water and oxygen.

Pulp Preparation

If the pulp and paper manufacturing process are split – it is at this stage that the pulp will need to be transported to the paper mill – in this case, pulp is dried and cut into bales. For an ‘in-line’ process, the pulp is cleaned, refined and purified in a 97% water mix containing both long and short cellulose fibres.

Wet section

The pulp mix is poured from  the ‘head box’ onto a wire mesh - usually made from nylon - called 'the wire'. The fibres mesh together on the wire whilst water is drained to form the sheet. Water is collected, recycled and ultimately treated prior to being returned to the environment often cleaner than when extracted.

Pulp transformation

As the water drains, the pulp mesh becomes a wet paper base. The paper base is fed into the press section where it is pressed between two absorbent cylinders to extract more water.

Drying (first stage)

Most of the remaining moisture in the paper is evaporated in the drying section as it goes through a set of heated cylinders. The now dry paper web is called the base paper.

Coating

To improve the surface of the base paper, it receives a coating of ‘size’. The sizing material is fed onto rollers from a vat, the sizing is to reduce the papers moisture absorbency.

Drying (second stage)

Having been 'wetted', the base paper goes through another drying stage to eliminate moisture added by the coating.

The Jumbo Reel

At the end of the paper machine, paper is wound onto jumbo reels. By using a flying splice arrangement between reels, the machine speed remains constant. Depending on the product and substance, this reel can weigh 15-20 tonnes.

Final coating

After quality checks and depending on the required finish, the coating(s) are applied on the coating machine. The coating contains a mixture of mineral pigments, binders (synthetic latex etc.) and colour additives.

This reel is then cut down into smaller reels which can be packaged or further cut down and packaged as sheets.