Fewer sleepless nights for millions of children and their parents, fewer tears, and more convenience – these are the "dry facts" achieved by a special chemical product: superabsorbent polymers, the technological secret behind the worldwide success of disposable diapers.
For the past 25 years, superabsorbents have been manufactured on an industrial scale at a plant in Krefeld, Germany. The small granules can absorb up to 500 times their own weight in liquid to form a gel that, unlike a sponge, retains moisture even under pressure, for example the weight of the baby wearing a disposable diaper. This quality makes superabsorbent polymers a popular choice for a wide range of hygiene articles such as baby diapers as well as feminine hygiene and incontinence products. Evonik is one of the world’s largest producers of superabsorbent polymers, with Krefeld as primary source of superabsorbents for Europe.
The first large-scale production plant for superabsorbent polymers in Krefeld went into operation in 1986. This ushered in the international breakthrough for FAVOR® brand superabsorbents. Research into superabsorbent polymers had begun in Krefeld in the 1970s. Today, FAVOR superabsorbents are used in more than 40 billion diapers every year. Weighing in at about 40 grams, modern diapers are less than half the size and much thinner than those of the 1980s, which weighed more than 100 grams – a real sign of progress. And the research continues. Although a typical diaper is worn only for a few hours, it is expected to fulfill high expectations. That’s why ongoing innovation is a high priority for FAVOR superabsorbents. In close collaboration with leading manufacturers of hygiene articles, researchers, and technicians at the Evonik laboratories are constantly working to develop new and even better superabsorbent polymers and develop the trends of tomorrow.
The current trend is toward less cellulose. The goal is ultra-thin hygiene products that are more comfortable to wear, require less packaging and create less waste. To achieve this, the liquid retention capacity of the polymers must be further increased, for example, or the distribution of moisture must be adapted to meet the precise specifications of the customer even better. Current research is likely to lead to superabsorbents capable of retaining even more liquid, so diapers can be considerably thinner. That means manufacturers need far fewer raw materials, resulting in simplified manufacturing processes and savings on production and transport costs. It is conceivable that diapers will soon look just like normal underwear.
In 1997, a year after the plant in Krefeld opened, a second facility went into operation in Greensboro, North Carolina. Additional facilities followed in 1992 and 1999 in Krefeld, 1993 and 2000 in Greensboro. A plant in Garyville, Louisiana was added in 1996 and one in Rheinmünster, Germany in 2006. In 2011, Evonik entered into a joint venture with Saudi Acrylic Acid Company (SAAC) to manufacture superabsorbent polymers in Saudi Arabia. The facility is scheduled to produce 80,000 tons per year beginning at the end of 2013 and represents an important step for Evonik in the growing Middle East market.
Superabsorbents Made in Krefeld– a quarter century of success
Read more: Polymers 77