Abrasion and tear resistance
When it comes to abrasion and tear resistance, it is not news that Stathane polyurethane outperforms rubber. In applications where abrasion is an important factor, Stathane is known to far outperform other materials.

Elasticity and compression
Mechanical components made of Stathane have equal elasticity and strength, so they can be stretched, compressed and returned to their original shape. Plastic or rubber can crack and not return to their original size. In terms of compression, Stathane is also better and has a wider range of hardnesses from 20 Sh A to 85 Sh D to suit all applications.

Temperature resistance
As far as temperature resistance is concerned, Stathane has good heat resistance. It can remain flexible at low temperatures, whereas rubber tends to harden. It is important to note that rubber parts can be more effective than polyurethane parts in very high temperature applications.

Chemical and ozone resistance
Polyurethane parts outperform rubber in terms of chemical and ozone resistance. They retain impressive resistance to oils, greases, fats, hydrocarbons and solvents. Although rubbers have good resistance to organic acids, alcohols, ketones and aldehydes, they are no match for polyurethane when compared to other chemicals. However, due to the diversity of the products, it is advisable to ask us to validate their resistance

Usually produced in aluminium or steel, moulds for the production of polyurethane parts can be expensive and not justified for the production of very small series. Our process requires good temperature resistance in order to maintain the geometry of the part. We develop 3D printed moulds from a high performance resin.

Vulkollan® is a polyurethane elastomer developed after the war by the Bayer company, now Covestro. This system is produced by the reaction of an NDI Desmodur © 15 diisocyanate and a polyol. Being the first of its kind on the market, it had the reputation of being the best polyurethane elastomer, is this still the case?

There is no doubt that for dynamic applications its properties allow it to have a long life and increased performance. However, it is important to define what is meant by dynamic. To simplify, we can consider that dynamic applications are those where the material will have to take a significant point or permanent load with a high operating cycle resulting in internal heating of the material. This heating can be detrimental to the longevity and performance of the material.

Vulkollan also combines the advantage of good abrasion resistance.

The reaction of isocyanates and polyol requires a demanding process control and does not allow for a long shelf life of the material before processing. The high raw material cost and the demanding post-cure cycle of several weeks also make for long production times.

The NDI hardness range is limited to 80 - 95 Sh A. Vulkollan® does not allow for low or high hardnesses in Sh D.

These requirements are significant risks for processors to produce parts that do not meet the desired dynamic requirements.

Are there any alternatives?

TDI + MBOCA systems have long been an economical alternative but never an equivalent to NDI. Moreover, MBOCA is an amine suspected of being carcinogenic and is currently banned from processing in Europe, unless an exemption is granted.

Other TDI + MCDEA Lonzacure® elastomers can be offered for dynamic applications. However, the cost of these elastomers does not allow them to compete effectively with Vulkollan today.

Research into polyurethanes in recent years has led to the development of new MDI-type materials which give very satisfactory results for dynamic applications (see our Strathane U series formulation).

The geometry of the part will also be an important variable in the quality of the parts produced. Good design can reduce heat build-up.

Conclusion

The design of the parts becomes strategic. Where Vulkollan allowed for ease of design, today it is perhaps necessary to think about the geometry of the parts so that the energy absorbed can be better dissipated. Our engineering department is at your disposal to optimise the design of your dynamic parts.