Silicones for Textiles

Thanks to their excellent properties, silicones are widely used in the textile industry. Water-repellent treatment causes rain to run off in little beads. Yet the fabric can still breathe, so sufficient air still reaches the skin. Pigment prints only really come into their own when silicones are used. They also prevent felting of wool, as well as being used as softeners.

For a long time, woolen threads were etched with chlorine so that they would not felt. The use of silicones has now eliminated emissions of chlorinated organic compounds. The silicones also confer a soft hand on the wool.		Surface treatment with silicones can yield textiles which are water-repellent but nevertheless breathable. This is accomplished with long-chain siloxanes that bond via amino groups on the fiber. The hydrophobic organic groups are located on their backs. - See also Hydrophobic properties of silicone fluids", video (wmv or mov) and flash animation.		Impregnation with water-repellent keeps the interior of the tent dry and optimally air-conditioned because of the material’s air permeability. Fibers metallized with aluminum soon cause the air in tents to become stuffy . In addition, the silicones withstand even the most extreme temperature conditions.

When colored textile fabrics are treated with silicones, their colors look more vivid. The silicones render the surface smoother and light is reflected less diffusely.		Impregnation with silicone lubricant has smoothed the surface of the sewing thread. The thread can now be processed much more easily than an untreated thread.

Another important application of silicones for textiles is as softeners. Long-chain polydimethylsiloxanes with amino-functional side groups are best suited for this purpose. The amino groups anchor the silicone to the fiber by way of attractive electrostatic forces. Interfiber friction is reduced in this way, producing the desired softener effect. Silicone applied as a microemulsion can penetrate into the fiber, making it stronger and increasing its volume.

For towels, the hydrophobic property of silicones is undesirable. Towels should of course be soft and fleecy, but they must be able to absorb sufficient moisture. In order to satisfy both requirements, the silicones used here have a cyclohexyl group attached to the amino group. These silicones are also characterized by good heat resistance, which is important for industrial drying.

Siliconized textile coatings on tenting, protective clothing, sports clothing and airbags have to meet extremely tough requirements. Textile coatings are therefore tailored jointly by our globally active WACKER team and our customers from the textile industry. ELASTOSIL^® silicone rubber grades are often used for this application. The silicone rubber is usually applied to the fabric by roll-coating or extrusion.