Whey as a surface treatment for paper and board to obtain water-repellent properties

Whey has been used for centuries for the surface treatment of various materials. Especially for masonry, whey was used as a coating agent until the beginning of the century and, among others, supposedly increased the plaster holding characteristics. Whey is a by-product in cheese production. A reasonable application of this by-product, beyond its use in animal feed, is therefore of great economic interest.

In different research projects carried out by the the Research Institute, it was possible to confirm the traditionally good water-repellent properties of whey. Based on these studies, a water-repellent effect and/or reduced water absorption through the use of slightly modified whey coating on cardboard could be proven.

Benefits of this technology:

  • Increases the water-repellent properties of paper and board (3-10 fold reduction of the water absorption compared to the initial value)
  • Further utilization of a by-product
  • Use of only slightly modified whey
  • Suitable for low-quality paperboard with high water absorption levels
  • Only minimal change in the original surface colour and structure
  • Ensures breathability
  • Natural material

To avoid that the coated samples must be stored under special conditions for a relatively long time in order to produce a water-repellent effect, a modified whey was developed with an extended shelf life that requires no special storage treatment. The water-repellent properties are lower compared to the original whey, but the efficiency and industrial applicability are improved.

Some research has to be done prior to a possible industrial implementation. While the water-repellent properties are proven, the effectiveness is greatly depending on the composition of the cardboard and the quality of the whey. The raw material (untreated whey) is inconsistent in its composition, for example due to seasonal influences, which in turn results in large fluctuations in the property profile. With further studies as well as with improvements made in the field of full-whey coating, it is expected that the water-repellent effect can be increased. According to the current state of knowledge, however, an optimization is only possible following detailed fundamental research into the mechanism governing the water-repelling effect.

Despite the necessary research effort, following products can be identified as examples for possible areas of application:

  • Coating of cardboard packaging e.g. water-repellent cardboard trays
  • Water- and stain-resistant tiles e.g. for brick buildings
  • Subsequent weather protection of untreated stones
  • Monument conservation according to the Charta of Venice
  • Wood protection with no loss of breathability

Contact and Organization Details

Dr. Johannes Bergmair

Head of Life Science Department,

Austrian Research Institute for Chemistry and Technology (ofi)

Tel. : +43 1 798 1601 976

E-mail: Johannes.bergmair@ofi.at