Roger Bakowski, Leiter des TPU-Marketings in der Region Europa, Mittlerer Osten, Afrika und Lateinamerika (EMEA/LA) in der Business Unit Polyurethanes bei der Bayer MaterialScience AG The topics we have selected in this, our fifth newsletter, reflect many of the strategic approaches with which we aim to further internationalize and expand our business. For example, we have focused more strongly on the growth market of eastern Europe and, in this connection, have extended our distribution collaboration with ALBIS. Another approach involves new material developments, with which we want to attack established applications for other plastics. For example, the products in our new Desmopan® 98 range are very suitable as substitutes for polyamide 11 and 12. This is also the top story in this newsletter. We are also working specifically with creative, medium-sized companies in the compounding and additives scene. Our aim here is to provide our materials with additional valuable properties and to align our range of products even more specifically to new market requirements and technical trends. On this subject, our newsletter also features the new, permanently conductive transparent TPU from geba’s Desmovit® range and ROWALID IR, the heat-reducing, IR-reflecting pigment from ROWA. As you can see, we are always good for an innovation or two! We think you’ll be surprised and inspired. Pleasant reading! Sincerely,

Ihr Roger Bakowski

Desmopan® 98 range – an economical alternative to polyamide 11 and 12

We already introduced you to the four representatives of our new Desmopan® 98 range in a previous newsletter. In the meantime, several projects with customers have shown that, despite their somewhat higher density, these new products can be an economical alternative to polyamide 11 and 12, and also to polyoxymethylene (POM). While their mechanical and thermal property profiles are comparable, other properties of the Desmopan 98 products – impact strength, elongation at break and ease of application, for example – are even superior. They could therefore be used as substitutes for polyamide 11 and 12 in a number of typical applications, such as the production of screw conveyors, slide rails, slide bearings, gears, rotor blades, switch and housing parts, rollers and roller coverings.

Low stiffening factors, aging-resistant in hot oils

One reason for developing the new polyether-based range of products was the call by many customers for non-reinforced, UV-protected TPU materials with extremely high resistance to hydrolysis and microbes plus excellent low-temperature flexibility and toughness. With a flexural modulus of elasticity of 200 to 1,000 MPa, the four new TPU grades cover a very wide stiffness spectrum. They can be injection-molded, and, in particular, extruded into tubes and flat films {Fig. 1}. The mechanical properties enable them to be used over a wide temperature range. This is attributable to the low stiffening factors ranging from 2.8 to just 1.6, which also means high rebound resilience. Stiff material grades, in particular, are characterized by an aging resistance in hot oils and lubricants that is unusually high for TPU. For example, even after 168 hours in standard test oils at 160 °C, Desmopan® DP 9873DU exhibits barely any swelling and, despite the high thermal stresses, still has good mechanical properties.

Fig. 1

Improved flow properties, more stable production process

The four TPU products are comparable to polyamide 11 and 12 with respect to abrasion resistance and softening behavior, but exhibit better elongation and elongation at break. In most cases, they also have better impact strength. Their melting points and heat resistances are also higher, opening up a wider field of application for parts made from them. Desmopan® DP 9873DU, for example, is heat-resistant from -75 °C to around 105 °C (short-term peaks up to 120 °C), Table 1.

Our TPU construction materials also score heavily with their ease of processing. Their melt flows better than that of polyamides 11 and 12, as is shown in {Fig. 2} with reference to the flow path/wall thickness diagram for Desmopan® DP 9873DU. This means they can also be used to produce thinner wall thicknesses and more delicate part geometries. They also offer greater scope in processing because the processor can lower the melt temperature or the injection pressure. This offers greater economic efficiency through shorter cooling and cycle times and/or greater flexibility in the choice of machines and production planning because smaller injection molding machines can be used. The processing window is wider both for injection molding and for extrusion, making the production process more stable. Fluctuating processing parameters – particularly temperature changes – do not therefore immediately result in manufacturing and quality problems.

Fig. 2

Much greater notched impact strength and elongation at break

Desmopan® DP 9873DU, in particular, proved to be an effective alternative to non-reinforced polyamide 11 and 12. While it has comparable values for the tensile and flexural modulus, tensile stress at break and hardness, its notched impact strength at -30 °C is about twice as high (11 kJ/m2, conditioned, ISO 179/1eA). With a heat distortion temperature of 53 °C (HDT/A, ISO 75), is also noticeably more resistant to heat {Table 1}. Desmopan® DP 9868DU, on the other hand, is ideal as a substitute for plasticizer-modified polyamide 12. Its key advantages are its elongation at break of 272 %, which is around four times higher (conditioned, ISO 527), and its notched impact strength of 16 kJ/m2 at -30 °C, which is about five times higher. Like its three siblings, it does not contain any plasticizers or halogens.

The more flexible Desmopan® DP 9855DU and DP 9864DU grades (56 and 62 Shore D respectively) have a similarly good property profile as the flexible polyamide 12 grades bearing elastomers, though they are more economical because the elastomer modification of the polyamides is comparatively expensive.

We are currently working to reduce the stiffening factors of our new TPU materials in order to further improve the way they behave at low temperatures. One approach here is to use impact modifiers with greater compatibility.

Focus on eastern Europe – collaboration with ALBIS extended

We are in the process of expanding our successful 40-year collaboration with ALBIS PLASTIC GMBH. The Hamburg-based distributor and compounder will now also distribute our Desmopan® products in Russia, Romania, Croatia, Serbia, Slovakia, the Czech Republic and Slovenia. ALBIS has proved over the years to be an effective distributor for us because they are able to regularly supply product to the customers quickly and flexibly within only 24 hours from their 35 warehouse sites. We can also rely on ALBIS to have competent local technical service that extends from material selection and mold design through to processing and start of production.

In addition, ALBIS also performs the compounding of tailored, customer-specific TPU products formulated on the basis of our Desmopan®. One example of this are the metallic grades from the ALCOM® range of system compounds. The portfolio is rounded off by a broad selection of color and functional batches designed specifically as colorants and additives for Desmopan®. They are based in part on our TPU.

ALBIS has long served us as a distributor in Germany, the Benelux countries, Switzerland, Austria, Scandinavia, the UK, Ireland, France, Poland and Spain. The company is regarded in Europe as one of the leading distributors and compounders of engineering thermoplastics.

Fig. 3, from www.desmopan.de , „Service“, „Kooperationen“, „ALBIS SERVICE GMBH“

Transparent and permanently antistatic – TPU compound with FDA approval

The geba Group has extended its range of electrically conductive Desmovit® LFC TPU compounds with a new transparent grade. Products made of Desmovit® LFC transparent can be approved by the U.S. Food and Drug Administration and are thus suitable for use in the medical and food sectors. Desmovit® (www.desmovit.eu) is the trade name for thermoplastic polyurethanes (TPU) containing reinforcing agents and other additives produced by the geba Group and Bayer MaterialScience AG. All the Desmovit® compounds are based on our Desmopan®.

Permanently conductive, excellent mechanical performance, free choice of color

One particular strength of the new product is that the conductivity additive is integrated permanently into the polymer matrix. Parts made from it are therefore electrically conductive not only on the surface but through their entire structure. Consequently, this conductivity is retained throughout the life of the part, even if it is subjected to abrasive stresses. In contrast, the antistatic behavior of other commercial conductive TPU compounds relies on additives that migrate to the surface of the product and only then develop their antistatic effect, which, however, deteriorates considerably over the course of time.

Another advantage of the new material is that the incorporation of the conductivity additive does not impair the mechanical performance of the TPU. The customary benefits of TPU, such as its high abrasion and tear resistance, are therefore retained in application Further compounding – for example with UV stabilizers – does not lead to any significant impairment or loss of the permanently antistatic behavior and does not therefore affect the approval for use in food technology. A wide range of colors can be selected.

Advantages in medical and food technology

Conveyor hoses are one possible application in food technology. This is where the material’s high abrasion resistance comes into its own, as it ensures that the food product being transported does not become contaminated with particles or additives. In the past, other TPU hose materials frequently resulted in contamination with such things as carbon black or other additives. The high transparency of the new TPU compound also permits permanent visual inspection of the material being transported, thus production problems can be recognized at an early stage and countermeasures enacted quickly. The excellent conductivity of the material is demonstrated, for example, by the fact that conveyor hoses produced from it conform to the technical rules for operational safety (TRBS) 2153 “Avoidance of ignition risks resulting from electrostatic charges.”

Fig. 4

Fig. 5

IR-reflecting pigments – “cool” additives for keeping your cool while driving

Hot summer days are not necessarily a pleasure if you are driving a car, because the infrared radiation in the sunshine can really heat up the surfaces of plastic components in the interior, such as the dashboard. Help is on the way thanks to an innovative additive developed by the ROWA GROUP. ROWA GROUP is a medium-sized, international family-owned company, with which we have enjoyed a long and fruitful partnership, particularly in the development of master batches. ROWALID IR is a range of special pigments that, when incorporated as additives into thermoplastic parts, reflect a large proportion of the infrared (IR) light in the sun’s rays. Consequently, car interior components do not heat up as much. For example, samples produced from an ester-based TPU Desmopan® colored deep black and frequently used in car interiors remain around 10 °C cooler in standard long-term IR radiation tests when ROWALID IR pigments are used {Fig. 6}. This result is all the more remarkable because black parts absorb more IR radiation and thus more heat than light-colored parts.

So far, the temperature-reducing behavior of the pigments has been proven not only in TPU, but also in TPO, PP, ABS, ABS+PC, PMMA and PVC. The additives can be combined with all colors, including transparent ones. Their “cooling” effect also has the advantage that the plastic parts are less subject to deformation in the heat of the sun, and also have greater stiffness and strength. Furthermore, the service life of the parts increases because the thermal stress (aging) is more moderate.

We see strong application potential for ROWALID IR in our TPU grades for car interiors {Fig. 7}, which are used for the production of e.g. instrument panels, trays or components in the upper part of center consoles. That also applies to our soft-touch TPU grades. Their tactile properties are unaffected by the addition of the IR-reflecting pigments.

Fig. 6

Fig. 7