Stock preparation

The stock in the blend chest contains the correct balance of fibre chosen to give the paper the desired properties.

Chemical fibres have always passed a number of refiners before they land up in the blend chest. Sometimes mechanical fibres, too, are treated in a refiner: they are post refined.

After the blend chest the stock is forwarded to the last stock chest: the machine chest. On the way to the machine chest there is a final regulation of the stock consistency.

If dry strength agent is added it is often brought to the stock in the machine chest. If rosin size is used, alum, too, may be found in the stock. The other chemicals are often added a bit later.

Source: Metso