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Non-iron convenience

Cotton finishing keeps textiles in shape

Ironing? No thanks! This tedious task tops the list of unpopular household chores, right along with scrubbing floors and washing dishes. But people who like to wear cotton can hardly avoid the nuisance of having to iron their clothes. Even cotton goods labeled “easy-care” look better if the owner has taken the trouble of doing some touch-up ironing to smooth out any residual wrinkles in the shirt or trousers.

Now BASF has a new method (patent applied for) that makes ironing less important than ever before: The company’s researchers have developed an especially gentle finishing process for textile manufacture. The BASF process makes cotton fabrics for shirts, dresses, bedlinen or decorative fabrics significantly smoother than conventional methods can. And it does so anew with every laundering cycle. What’s more, textile manufacturers find it easier to apply this process and to control the fabric’s properties during manufacture.

The story

The main weapon against wrinkles in clothes has still been the tried and true iron - much as in great-grandmother’s days. However, textile manufacturers have managed to get much closer to meeting the “non-iron” claim through improved finishing of fabrics. “Consumers insist on this property even after x wash cycles,” says Hans-Gunter Just, manager of Textile Quality Control at German mail order giant Otto Versand.

It is BASF’s aim to make the iron superfluous with a new process for which a patent application has been filed. The company’s researchers have developed a particularly gentle method for the finishing process textiles go through. If fabrics are treated with crosslinkers such as BASF’s Fixapret grades the textiles look uncrumpled and feel especially soft. A cotton shirt without durable press finishing is not a pleasant sight after washing and spin-drying. Crumpled and creased, it’s fit only for the ironing board. But when a cross-linking agent like the Fixapret brands from BASF is added during the cloth finishing process, the fabric acquires dramatically improved qualities including a creaseless look and an especially soft feel. The cross-linking agent reduces water absorption during the wash cycle. As a result, less water remains after spin-drying too. “That’s how we combat the main cause of crease formation,” explains Dr Friedrich Reinert, textiles researcher at BASF. An additional benefit: Garments retain their shape better, shrink noticeably less, are more colourfast and more durable, plus they dry faster. A tip from the BASF experts: It is best to hang the durable press shirt dripping wet on the hanger to dry. Once you put it on to wear, it smoothens out a bit more. So you can leave your iron where you like it best: In the cupboard.

The background

Cross-linking agents keep natural fibres from swelling. The reason for creasing of textiles is readily explained: During the washing process, cotton fibres swell, change their position and fail to return to their original state during drying. A shirt without durable press finishing is then actually hard to iron, and even calendered bedlinen won’t turn out entirely smooth. In the durable press finishing process, the textile web is passed through an immersion bath with at least two substances: A cross-linking agent and the catalyst. In the previously established process - wet cross-linking - the cross-linking agent condenses on the cotton fibre within 20 hours at 30 degrees Celsius. Since sulfuric acid is used as the catalyst, this process is tricky: “The acid destroys the cotton fibre unless optimal parameters are strictly maintained”, explains BASF textile researcher Dr Friedrich Reinert. The need for multiple drying cycles makes this a costly process. And if the residual moisture isn’t exactly at the right level, there’s a substantial risk of producing low-quality merchandise.

As an alternative method, BASF has developed the Advanced Performance (AP) Finish. By using the cross-linking agent Fixapret AP, the condensation time in this method is reduced to just 45 seconds at 130 degrees Celsius. That’s all it takes to achieve the durable press effect. On the one hand, the fibre experiences less swelling during the wash cycle. “On the other, cross-linking creates elastic recovery forces that automatically restore the shape of the textiles after each laundering”, explains Dr Reinert. As a result, the fabric provides the comfortable wear that’s customary for cotton, but it no longer forms wrinkles.

The prospects

Durable press cotton textiles improve the quality of life. Even though the use of synthetic fibres is very common in current fashions, the sensation of pure cotton on the skin is widely preferred. “Cotton textiles will be even more appealing in the future, as new finishes improve quality and add value”, predicts Mr Thomas Pfisterer, global marketing manager of textile chemicals at BASF. “This means future demand will increase for easy-care cotton garments that are more comfortable to wear. Because a durable press shirt improves the quality of life and saves time for the things that really matter. That’s a customer wish textile finishers can now fulfill by using BASF’s AP Finish.”

BASF scientists have also tackled another problem: Textile finishing processes leave a small residue of formaldehyde in the fabric until the first laundering. Experts consider this amount harmless. But the objective is to keep it as low as possible. BASF’s AP Finish ensures absolute compliance with the Oeko-Tex Standard 100.

The Oeko-Tex Standard 100 is a product label issued by respected textile institutions and recognised throughout Europe for dermatologically compatible textiles. In the case of formaldehyde it guarantees values of less than 75 ppm (parts per million), ie. 75 parts of formaldehyde per million parts of textile fabric. “Once the textiles comply with the Oeko-Tex Standard 100, we envisage no further problems”, emphasises Mr Hans-Gunter Just of Otto Versand. “We don’t want any pollutants in our clothes, and every product must meet a set of ecological requirements.” And for those who want to be even safer: The first laundering removes any residual formaldehyde from the fabric, but the durable press effect is preserved.