The versatility of Polyurethanes

There are few products that can compete with polyurethanes in terms of versatility and popularity. From insulation to surf boards, from car airbags to window sealants, polyurethanes are everywhere in our daily lives.

Their growing success and increased use is further boosted by the fact that they are affordable, safe and recyclable, and these qualities make them the product of choice for manufacturers and retailers all over the world. Polyurethanes can meet the highest of consumer expectations, hence their mounting popularity. Unlike some other materials that might perform similar functions, they are not in short supply and can be manufactured according to exact specifications. For example:

  • Manufacturers of mattresses may demand a firmer consistency to the foams they use and polyurethane manufacturers could work with mattress designers to meet these specific requirements.
  • Car manufacturers may be obliged by law to ensure that noise levels inside cars fall below a certain level, and could then work with polyurethane producers to meet required targets. Entire door panels could be made of polyurethanes because of the different forms they can take.

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Case Studies

4 Wrinkle-free Polyurethane Skin for Service Robots [Friday, December 12, 2008]

Bayer MaterialScience AG (BMS) has been awarded the "Polyurethanes 2008" prize for innovation for its work on the "Care-O-bot 3" service robot.

"Care-O-bot 3" is a service robot for the home, conceived by the Fraunhofer Institute. BMS developed an elastic polyurethane skin for the external moving parts, which hardly wrinkles at all when the robot is in motion. "The skin is an intelligent combination of flexible polyurethane foam and polyurethane dispersion frothed foam. It is a completely novel, innovative class of material which, above all else, has great potential for use in the future robotics market", explains Manfred Naujoks, an expert in flexible polyurethane foams who accepted the award on behalf of BMS.

"The result has an extremely attractive look and a pleasantly soft feel. The thickness, density, color and surface texture of the material can be varied to meet the requirements of the respective application", says Dr. Andrea Maier-Richter. Although extremely flexible, the composite material patented by BMS is also very strong and highly resistant to standard cleaning agents and everyday chemicals.

This shows another area in which Polyurethane has been used to improve the efficiency and aesthetics of a product, with the potential for future use in robotics.

Flexible cable bushings with polyurethane gel

The new, intelligent cable sealing system from Hauff-Technik GmbH & Co. KG, Herbrechtingen, seals cables quickly, easily, and reliably.

Within the segments, the highly-flexible polyurethane gel Technogel® envelops the cables and lines, thereby providing excellent sealing properties. This high-performance material, which is based on polyurethane, moulds itself to each cable contour for a lasting perfect fit – and this holds true for even the smallest cable diameters. Moreover, it also boasts outstanding low-temperature flexibility and a high degree of compensation for movement.

This process involves a minimum of effort and eliminates the need to open up the entire system. The different coloured segments can be assigned separately, and spare places can be kept available for retrofit installations. The principle of coloured segments also allows cables to be sorted by function, e.g. data cables.

This area is just one example of the close collaboration between Bayer Material Science and its customers in the development of tailor-made system solutions with polyurethanes.

Polyurethane in this application has increased its performance and functionality.

1 - 0 for polyurethane foams [July 17, 2008]

One-thousand new miniature playing fields in Germany fenced in with metal-faced sandwich panels the German Football Association (DFB) is investing EUR 25 million in the construction of 1,000 miniature playing fields. To ensure the safety of the players and reduce noise for neighbours, the fencing around the fields is made of metal-faced sandwich panels incorporating a polyurethane foam system from Bayer MaterialScience.

Sandwich panels manufactured for this application by Fischer Profil GmbH of Netphen-Deuz, Germany, offer high mechanical strength and good sound absorption. The fencing around the field comprises panels with integrated goals, on which high demands are imposed. They must withstand impacts with players. To suit the needs of neighbours, the material must also function as a sound-absorber. Metal-faced sandwich panels have proven to be the material of choice, made from steel facings and a polyurethane rigid foam core.

Self-supporting polyurethane/metal sandwich panels were originally developed for insulating large facades and roofs in industrial buildings. They have been put to effective use in many segments of the building industry for more than four decades now. When used as a facade, they simultaneously function as a design element and, together with a coloured surface treatment, give designers great creative freedom. The sandwich panels are used in industrial and commercial construction, as well as in cold stores, warehouses, exhibition halls, sports halls, office buildings and transportation buildings (e.g. airports).

This is just another example of the almost unlimited potential for developing new polyurethane applications made possible by the material's versatility.

A material that is very much on track [August 19, 2008]

Better dimensional and weather stability than wood, lighter than concrete Railroad builders are turning increasingly to polyurethane composite marketed under the name Eslon Neo Lumber FFU from SEKISUI CHEMICAL CO. LTD., Tokyo as the material of choice for manufacturing the ties or sleepers that are used to support railroad tracks. The material is noted for the far greater durability of the ties and the correspondingly lower lifecycle costs. In Tokyo, plastic ties have been in service for more than a quarter of a century. They have been laid, for example, under the track for the Shinkansen high-speed train, and the FFU (Fiber reinforced Foamed Urethane) polyurethane ties have now been premiered in Germany.

Railroad ties must be able to withstand high mechanical loads and must also be dimensionally stable and weather-resistant over a long period to comply with the conditions for safe rail operation and low maintenance costs. Frequent temperature changes, radiation and moisture start to affect wooden ties after a relatively short time, and repairing the wooden track involves a considerable amount of material, time, organization and cost. In comparison polyurethane ties have an estimated service life of at least 50 years. With considerably longer maintenance cycles and associated cost benefits for the railroad operator, individual ties can be replaced quickly and accurately, helping to lower construction costs even further.

The flexural strength of the polyurethane ties is also very much higher than that of wood, even after 15 years, the material is also suitable for the construction of high-speed tracks.

The polyurethane material looks like wood and combines all the positive properties of the natural product with those of a modern composite product. The polyurethane ties can be processed in the same way as timber, and compared with concrete, the polyurethane material weighs much less and boasts the reproducible evenness that is important with turnouts. The polyurethane ties are also very suitable for bridges due to their lightweight and they can be manufactured in virtually any desired length and cross-section up to a current maximum of 9.60 meters.

The ecological compatibility of the polyurethane ties is also an advantage. As a rule, ties that have already been in service can be reused, or can be recycled in the same way as the production scrap.

The polyurethane system based on long-fiber reinforced Baydur® 60 integral skin foam comes from Sumika Bayer Urethane Co., Ltd., the Japanese polyurethane systems house in Bayer MaterialScience's global BaySystems® network.

Polyurethane in railroad ties, increases durability, safety and decreases cost.

Wheelchairs and wheelbarrows run smoothly on tires made of polyurethane foam [April 08, 2008]

No more flat tires

The British company Greentyre, has developed and designed tires that aren't affected by sharp objects or long periods of inactivity. The tires are made of micro-cellular polyurethane foam based on a Bayflex® system from Bayer MaterialScience. Products made of this innovative material are longer-lasting and much lighter than solid rubber tires.

To manufacture the tires, the mould is filled with a liquid reaction mix before being rotated during the foaming process. This ensures that the material is distributed very evenly across the whole tire circumference, which means that the tires will run very smoothly.

The material is virtually solid at the tire's outer circumference, and its even surface makes for excellent rolling properties. Thanks to the tire's good aging and weathering resistance, it retains its true-running properties in the long term, even when it remains in one position under a heavy load for an extended period of time and becomes compressed on one side. And the high elasticity of the micro-cellular material ensures that the tire’s rolling resistance is almost as good as that of an air-filled tire.

However, this tire technology is not just useful for leisure activities and gardening – it is also ideal for wheelchairs. The Greentyre Company has designed a very special wheelchair for disabled people. One key feature of the sophisticated design concept is its modular structure, which enables users to choose from an array options to meet individual clinical need and the type of use. If required, the wheels can also be removed at the touch of a button. Additionally, the wheels are equipped with ergonomic hand rims also made of polyurethane. The special feature of these hand rims is that they do not get sharp edges through wear and are pleasantly warm to the touch. The wheelchairs’ adjustable arm rests are also padded with this polyurethane foam. It seems that the versatility of this elastomeric cellular material knows no bounds.

This is just another example of the ever increasing versatility of polyurethane.

Lightweight stage sections thanks to polyurethane sandwich composite

Back complaints resulting from heavy lifting could soon be a thing of the past as the Dutch company Triple-E Lichtgewicht Meubilair B.V. in Winsum is now offering lightweight stage sections under the name “Flax-Deck” with external dimensions of 0.75 by 1.50 meters and a weight of only 16.5 kilograms. The low weight of the stackable and compact sections is due to a sandwich structure based on the Baypreg® polyurethane spray system from Bayer MaterialScience.

Generally lightweight and extremely stiff

Composite sandwich materials are generally lightweight and extremely stiff. The highly versatile stage sections consist of a light rigid foam core reinforced top and bottom with flax mats to absorb tensile forces, thereby increasing the strength of the composite. The sandwich structure can withstand a concentrated load of up to 150 kilograms. Its surface is protected by a highly abrasion-resistant and robust plastic layer.

Excellent adhesion

During production, the fiber mats made out of natural flax are first impregnated on both sides with the dual-component polyurethane system using a spray process. The mats and the expanded polystyrene (EPS) core are then put together to form a sandwich and inserted into a preheated mold. This highly economical, one-step production process creates a permanently stable, extremely robust and rigid structure capable of withstanding high mechanical loads. This is due in no small measure to the polyurethane system’s excellent adhesion to various materials.