Water and ink absorption

General informations

Several devices at the Physical Testing Laboratory are used to characterise absorption properties of papers and boards, such as absorption capacity and rate, sizing/writing degree, contact angle and surface energy.
The main product types tested are raw materials such as paper, tissue paper, folding boxboard, corrugated board or composites, or finished products such as labels, folding cartons, blister packaging, bags, tissue products, exercise books, note books, etc.
These tests can be performed either after standardised conditioning or after heat-, moisture- or cold-ageing.

Technical Data and Achievements

The following are some of the standards and methods that can be implemented at the Physical Testing Laboratory:

On papers and boards:

• Water-absorption capacity – Cobb method, inaccordance with ISO 535 or NF EN ISO 535.
  The contact time is adapted depending on theassessed materials (between 60s and 1800s)
• Pen writing sizing grade, in accordance with NF Q 03-015: determination or control of the sizing degree.

On tissue papers and products:

• Water-absorption time and water-absorption capacity, basket-immersion test method, in accordance with NF EN ISO 12625-8. This refers to the determination of the water-absorption capacities of a tissue paper or a tissue product. According to the principle described in the standard, sheets of the sample are placed in a cylindrical basket immersed in water. The results are expressed in terms of water-absorption time and water-absorption capacity.
• Resistance to disintegration in water, in accordance with NF Q 34-020. This involves determining the time taken for a toilet paper test piece to disintegrate in specified conditions. The testing method is suitable for all types of toilet paper, with the exception of those used in some specific toilets requiring a particular disposal method.
• Determination of disintegration in water in accordance with ISO 12625-17. This standard is based on the principle laid down in the French standard NF Q34-020, but is applicable to all tissue papers and products and not just to toilet paper. The percentage of material disintegration is determined at specified times.

For all adhesion- or wetting-related issues:

• Measurement of contact angles
• Determination of wetting kinetics
• Calculation of surface energy

Other methods:

• Capillary rise – Klemm method, in accordance with NF ISO 8787
• Water-absorption capacity after immersion in water, in accordance with ISO 5637
• Water absorption, drop test methods, – TAPPI T492 or TAPPI T813 or FEFCO method
• Sizing degree – Stöckigt method, in accordance with JIS P 8122.

Contact angle and surface energy		Water-absorption capacity, basket-immersion test method