Head of Business Development TPU in Europe, the Middle East, Africa und Latin America (EMEA/LA) in the Business Unit Polyurethanes of Bayer MaterialScience AG As you will see, our R&D work doesn't focus solely on new areas of application. We have also developed some new products for established markets. Examples include two new TPU grades for drive belts to boost production flexibility. As a treat for keen dancers, we also have a short article about dancing shoes with an innovative TPU heel protector. And it goes without saying that the newsletter includes a potential new application for Desmopan®, too. Initial research indicates that some of our highly transparent TPU materials are suitable for optical applications such as lenses. If we have inspired you, be sure to get in touch! We will help you turn your idea into an actual product. I wish you happy reading! Kind regards,

Ihr Jürgen Hättig

Easy to color – two new TPUs for drive belts

One major application in which the first-class mechanical properties of TPU are widely used is drive belts, including toothed belts for industrial drives and lifting belts for elevators. Desmopan® 392 and 790, two made-to-measure TPU materials, have been successfully established on the market for years. Customer requests recently led us to add two new grades – Desmopan® DP 3392A and DP 3395A – to our product portfolio for this application segment. Their properties are similar to Desmopan® 392 and 790 but they are natural in color rather than white. This makes them very easy to color, which has particular benefits with dark shades. Desmopan® DP 3395A is also a response to customer requests for a grade that is slightly harder than Desmopan® 392 but otherwise comparable.

Numerous advantages over steel cables

Toothed belts and lifting belts have long been made of TPU combined with steel, aramid or Kevlar cords. Virtually all the advantages of TPU come into play here, including its high flexibility, tensile strength, impact strength at low temperatures and excellent adhesion to the cord fabrics. TPU's good wear resistance, limited swelling in water, oils and greases, high resistance to gasoline and many solvents and low aging under the influence of ozone and sunlight are all impressively demonstrated in practice. When good resistance to hydrolysis is required, appropriate TPU grades based on a special carbonate polyol are the material of choice. Desmopan® 790, for example, is highly resistant to hydrolysis and microbial attacks thanks to its unique raw material composition.

Lifting belts highlight TPU's benefits. TPU makes them around a fifth lighter than steel cables, they last two to three times longer, are corrosion-free and also benefit from enhanced safety thanks to a higher load-bearing capacity. What's more, they offer better traction, deliver smoother and quieter operation, enable the use of smaller motors and are subject to significantly less wear.

Tailored product development

We now have four made-to-measure TPU grades for drive belts that are geared to this specific application and therefore differ in many respects from standard ester- or ether-based TPU. One strength is the good flowability of their melts, which also harden only slowly. This enables our TPUs in the belts to anchor themselves very firmly with the tensile members made of steel or synthetic fibers. They can also be used to make complex profiles with narrow tolerances, are easy to weld and run without squeaking. Their good compatibility with numerous backings, tooth coatings and a wide range of adhesives opens up a great many possibilities for modifying belts by applying coatings. Important properties for many applications are their resistance to greases and oils and their low swelling, even at high temperatures. Another point worth highlighting is the particularly good low-temperature flexibility, in some cases at temperatures significantly below -30 °C. The two new TPU grades perform even slightly better in this respect.

We will continue catering to the needs of drive belt manufacturers with new materials. For example, we are planning to develop softer ether- and ester-based TPU material grades.

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Desmopan® grades for elevator- and timing-belts

Physical Properties

TPU for top lifts of dancing shoe-heels

When dancing a lively tango or samba on a dancefloor, having the appropriate footwear is a must. The heels of the shoes are particularly important in this context. They must provide the dancer with a firm grip, look aesthetic and at the same time withstand considerable mechanical strain. The Indaca Group based in Elda near Alicante, Spain, has developed a TPU top lift for the heels of many models of dancing shoes that does just that. Indaca, one of the leading Spanish suppliers of high-quality plastic shoe components for the shoe industry, specifically utilizes the strengths of our ester-based Desmopan® 385 S in its product.

Non-slip and cushioning

The top lift is manufactured using injection-molding and placed over the actual heel, so that the sides of the heel are partially covered. Thanks to our TPU, the resulting heel tread has significantly more grip than heels made from other thermoplastics. In addition, it stabilizes the foot. The dancer benefits in terms of both safety and precision when executing a rapid spin. The TPU cushions the dance steps acoustically and mechanically. In doing so, the pleasure of dancing is not interrupted by the "clattering" of the heels. Breaking of the heel, which frequently occurs in the case of heels made from "hard" thermoplastics, is effectively prevented thanks to the cushioning effect. Wooden dancefloors or floors made from other sensitive floor coverings also benefit, as our TPU, with a hardness of 85 Shore A, is so soft in comparison to other thermoplastics that the heels do not scratch the wooden surface.

Transparent and durable

The significantly high level of transparency of the TPU material used for manufacturing the protecting top lifts, gives the actual heel and its design greater visibility. The TPU can also be painted, so that for some models of shoe the color of the heel is highlighted. Moreover, the dancers can enjoy their shoes for longer. The excellent mechanical properties of our TPU, such as its abrasion resistance, tensile strength and tear propagation resistance, ensure the heels have a long lifespan.

For more information regarding Indaca products and services, visit: www.indaca.com.

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Transparent with low dispersion – TPU for optical applications

We have recently been giving an increasing amount of thought to whether our transparent TPU grades could be suitable for making optical components. We have carried out some initial research, collaborating with partners in some cases.

Low chromatic aberration required

One key factor is the dispersive behavior of TPU grades when exposed to light from the visible wavelength range. Dispersion indicates how the refraction of light depends on its wavelength and/or color. With lens optics, for example, this phenomenon is responsible for colored edges around images of bright objects – an image error referred to as chromatic aberration. The smaller the dispersion, the less pronounced the chromatic aberration and the sharper the images that can be generated with the relevant optical systems, such as lenses. The absolute Abbe number is used to measure dispersion in the visible light range.

Six TPU grades of varying hardness

The research revealed that several of our highly transparent TPU grades have Abbe numbers of between 31 and 34 (see table). This makes them more or less comparable with other transparent thermoplastics that – like polycarbonate, for example – have already become established in the production of optical components. The Desmopan® grades listed in the table could therefore in principle be suitable for optical applications. They are all UV stabilized and are based on either polyester or polyether diols. Five material grades with hardnesses of 50 to 65 Shore D are available. They are suitable for applications that require a certain degree of stiffness. Desmopan® DP 3695 AU, on the other hand, is a softer grade with a hardness of 95 Shore A. One key advantage of our TPUs is the absence of stress cracks. They are also unbreakable, unlike materials such as PMMA.

Suitable for injection molding

Our TPU grades satisfy the relevant processing requirements, too. Properties such as good flowability and easy mold removal should make them suitable for the cost-effective manufacture of optical components – a conclusion confirmed by initial processing tests for optical applications. We will report on the progress of this research in due course.

New Desmopan® application brochure

We have updated our application brochure for Desmopan®. The new edition, entitled “Desmopan® – A high-tech material sets trends” can be downloaded from our TechCenter www.desmopan.de in the English section by clicking the button under “New product brochures”. A printed version is also available in both English and German from your field sales contact. The brochure provides a concise, richly illustrated overview of the most important and most recent applications for our TPU materials and explains the strengths of Desmopan® in the respective applications. Service elements are also covered, indicating how we support our customers at every stage from the product idea and material selection to component development and the start of production.

Desmopan application brochure

Upcoming events

We are taking part in various events and trade shows in the next few months. Come and visit us!

Fakuma

Together with other Bayer MaterialScience business units, we will be showcasing innovative and sustainable developments for plastics processors from October 18 to 22, 2011 at this year's Fakuma in Friedrichshafen. Stand B4-4206 in Hall B4 will focus on global megatrends such as climate protection, mobility, technology and health care. Innovations include new soft grades of Desmopan® for hard/soft technology.

Technomer 2011

On November 10, 2011 our TPU expert Mathias Lauter will deliver a lecture at the Technomer symposium in Chemnitz on Desmopan® DP 9855DU, DP 9864DU, DP 9868DU and DP 9873DU – hard thermoplastic polyurethanes with a high load-bearing capacity that excel in demanding extrusion applications.