A new diaper based exclusively on wood raw materials. That is the goal in the research project WooDi, in which SCA is cooperating with the pulp and paper association Södra Cell AB and Chalmers University of Technology.
Today’s diapers contain both fiber raw material as well as other components produced from fossil oil. Superabsorbents, for example, are oil-based plastic materials that revolutionized the diaper market at the end of the 1980s. Replacing this with wood-based material is a major challenge that the researchers in WooDi (wood-based diapers) are now tackling.
“The requirement is to create a structure of cellulose fibers so that today’s absorbent capacity is retained,” says Torgny Falk, SCA’s project leader for WooDi.
Stronger fibers
He explains that a diaper’s absorption core today comprises pulp fibers that are fluffed. The main task of the so-called fluff pulp is to disperse the liquid in the diaper. The superabsorbents lock in the liquids.
Torgny Falk, SCA's project leader for WooDi.
“To remove the superabsorbents, we want to attempt to further develop a somewhat modified cellulose that has higher absorption capacity and better capability to retain the liquid in the structure. This involves, for example, making the wood fiber stronger and stiffer. The project will run for four years and then we hope to have a finished proposal for how the fibers can be produced to provide for the retained performance of the diaper,” relates Torgny Falk.
Long-term sustainability
If the project is successful, there still remains a lot of work to start operational production. At the earliest in six to seven years Torgny believes that we can see an exclusively wood-based diaper on the market. As a sub-goal, he sees the possibility of reducing the proportion of oil-based superabsorbents in the diaper and increasing the amount of cellulose fiber.
“The main focus is to develop a product that is environmentally as sustainable as possible and in this context renewable material from the forest industry plays a key role,” contends Torgny Falk.
FACTS
SEK 35 M over four years
The WooDi research project is managed by Chalmers University of Technology in cooperation with SCA Hygiene Products and Södra Cell AB. Both companies are investing SEK 7.5 M each over a four-year period. The government agency Vinnova is supporting the project with an additional SEK 20 M.
Diaper holds two liters
In laboratory tests, today’s diaper has demonstrated the ability to absorb up to two liters of a salt solution. However, urine is a more complex liquid, which contains many different types of salts that affect absorption performance. A diaper on a child normally fills with up to one half liter of urine.
Text: Susanna Lidström