The demand for high performance polyurethanes is on the rise in heavy process industries. However, the proliferation of next-generation polyurethanes creates challenges in the selection of the best material for any particular application.
A — The Alternatives
The composition of polyurethane is not always the same. For instance, isocyanates form one part of the prepolymer and affect the cure characteristics of the polyurethane. The main alternative high performance polyurethanes are either diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI) while alternatives also include hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI).
While functionally they have the same performance properties, the latter two exhibit specific characteristics such as inhibition of yellowing in parts that will be exposed to sunlight.
Polyols also contribute to the function of polyurethane: in particular polyether polyols produce Shore A and Shore D hardness systems that depending on additives used, deliver high tear strength and superior abrasion resistance; polyester polyols are combined isocyanates to form Shore A hardness with outstanding elongation characteristics. The formulation and processing temperature decide the final polyurethane type. Hybrids of these create even further alternatives.
B — The Benefits
The new high-performance polyurethanes help create high heat, high impact, high modulus products as well as systems that can withstand exposure to gouging, cutting, chemicals, oils and solvents. Some MDI polyurethanes are now FDA-approved for dry food contact and suitable for parts that come in contact with oats, wheat and cereals.
However, the real benefits can be observed when compared to traditional steel lining systems. Simplicity of installing polyurethane is one such benefit; when compared to steel that requires labour intensive construction and welding, a polyurethane lining system is lightweight and can be glued or bolted on. Significantly lower noise levels not only improve employee working conditions, but also the general environment especially when operations are located close to residential areas.
C - Your Choice
Selecting a polyurethane lining should be based on the different conditions present in every bulk handling site. For instance, abrasion resistance should be prioritised if it is the primary requirement, followed by hardness, elongation, impact strength or ability to handle a load or high temperature.
Kinder & Co's K-Superline polyurethane is a unique purpose-engineered polyurethane designed to meet the particular demands of heavy process bulk handling, and available in six colours depending on its sliding abrasion and level of elasticity, impact angle and resistance, plus suitability for lump size. By correctly matching specific requirements against K-Superline characteristics, one can find an easy and genuine replacement for steel wear liners.
With the recent advances in chemistries, a next-generation of thermoset polyurethanes now offers new options other than steel for moulding durable flow materials. Offering unique combinations of performance characteristics such as excellent tear strength, high resistance to abrasion, as well as high impact strength, polyurethane makes good business sense.
Observing that Australia has a reputation for being an early adopter of new technologies, Neil Kinder, managing director at Kinder & Co calls upon manufacturers to utilise the benefits of high performance polyurethanes to their advantage.