Polymers and chemicals make their mark in the home

Dean Palmer takes a look at how engineering polymers are playing a vital role in the development of exciting new products for the home consumer market Engineering polymers have been instrumental in the development of a revolutionary design of water filter technology for the home. Take Brita's new 'Elemaris' water filter pitcher, which uses a thermoplastic polyurethane (TPU) from Bayer, 'Desmopan DP 6386A', for the handle and four rounded sections of the base. "Our material was preferred because it is particularly resistant to scratching, abrasion and slipping," said Georg Fuchte, manager Thermoplastic Polyurethanes at Bayer MaterialScience. "It produces soft surfaces that are pleasant to the touch, highly robust and show barely any signs of wear and tear even after many years of use". As well as the water filter pitcher, Brita also fits its 'Atlantis' table water filter with components made from Desmopan DP 638A. According to Fuchte, TPU has a polyether base and is therefore highly resistant to hydrolytic and microbial degradation. It doesn't contain plasticisers or halogens but adheres well to many thermoplastics. It also has high chemical resistance to typical household chemicals such as oils, greases and cleaning agents. The filter pitcher is produced with a two-component lathe tool using hard/soft technology and injection moulding. First, the transparent base of the pitcher is created from hard Styrene Acrylonitrile Copolymer (SAN). Then the soft components made from TPU are moulded using hot runner technology. "Our TPU material has the advantage that its melt solidifies very rapidly," explained Fuchte. "Production is therefore fast and cost effective. It can cut cycle times by up to 35 per cent compared to standard polyether grades of Desmopan." Novel chemical processes are also helping to create new designs of wooden garden chairs. Most wooden garden chairs struggle to satisfy the dual objectives of comfort and durability (particularly when it comes to weather conditions). BASF has developed a patented process - known as 'Belmadur' - to modify pine and beech wood by cross-linking the cellulose molecules, resulting in wood quality that rivals expensive, tropical hardwoods. The wood is much harder and more durable, with excellent dimensional stability, making the material ideal for hard wearing, long lasting flooring, garden furniture, window frames, doors and cladding. Pigment can also be added to the Belmadur solution in order to provide colour throughout the cross-section. Many shades are possible and the pigments can be used to complement and enhance the natural colour of the wood. Design pioneer Thonet is using BASF's Belmadur technology to create a new range of garden cantilever chair made from beech wood - allegedly, the first time a chair made from beech wood can be used outdoors. The chair offers enhanced comfort, unlike conventional wooden slats, and the large seat area does not leave any impressions on the skin. Becker KG in Germany manufactured the backrest and seat of the weatherproof S43 cantilever chair. Becker is Europe's leading supplier of moulded beech and uses Belmadur to manufacture weather-resistant moulded parts from German beech wood. Beech wood is normally rated as durability classification 5, but by applying Belmadur, durability classification 1 was achieved. Pointers * Bayer's Desmopan TPU has a melt that solidifies very rapidly, meaning cycle times can be reduced by up to 35% compared to standard polyether grades of the material * BASF's patented Belmadur technology has helped a garden chair manufacturer develop comfortable, weather-resistant beech wood furniture, with properties that match expensive, tropical hardwoods