PU (Polyurethane)

Overview

Polyurethane (PU) elastomer occupies a unique position between rigid plastics and conventional rubbers. It can be formulated across a very wide hardness range — from soft, gel-like materials to semi-rigid solids — and consistently delivers higher abrasion resistance than most natural and synthetic rubbers. PU is also notable for its resistance to cuts, tears, and impact damage. It is used in wheels, rollers, conveyor belts, lining plates, bumpers, and wear pads where rubber would wear out too quickly. PU is not a single material but a broad family; properties vary significantly by formulation, hardness, and manufacturing method.

Working properties

• Abrasion resistance

  PU elastomers have outstanding abrasion resistance — significantly better than most rubber grades and comparable to engineering thermoplastics in wear-intensive applications. This is the primary reason PU is specified for lining plates, screen decks, wheels, and conveyor belt covers subject to abrasive wear.

• Hardness range

  PU can be formulated from very soft (Shore A 20) to semi-rigid (Shore D 70+). The appropriate hardness depends on the application — softer grades for vibration absorption and flexible sealing; harder grades for structural load-bearing and wear surfaces.

• Tear and cut resistance

  PU has significantly better tear and cut resistance than most rubbers at equivalent hardness. This extends component life in applications where sharp or angular abrasive particles are present.

• Chemical resistance

  PU is resistant to oils, greases, fuels, and aliphatic hydrocarbons, making it useful in hydraulic and lubrication system seals and components. It is susceptible to attack by hot water, steam, strong acids, alkalis, and many polar solvents — confirm compatibility for your specific environment.

• Temperature limitations

  PU is not suitable for high-temperature service — it softens and loses mechanical properties at relatively modest temperatures compared with engineering plastics. For elevated-temperature or steam applications, other rubber grades are more appropriate.

• Hydrolysis susceptibility

  PU can degrade through hydrolysis (reaction with water) over extended periods, particularly in warm, humid, or wet service. Not all PU formulations are equally susceptible — hydrolysis-resistant grades are available for wet environments.

Typical uses

• Abrasion-resistant lining plates for hoppers, chutes, and cyclones
• Industrial wheels and rollers on trolleys, conveyors, and handling equipment
• Conveyor belt covers and impact bars
• Hydraulic and pneumatic seals and scrapers
• Bumpers, pads, and shock-absorbing mounts
• Screen deck panels and wear surfaces in mineral processing

Things to confirm before ordering

• Hardness — specify the required Shore A or Shore D hardness for the application; this is the single biggest determinant of mechanical behaviour.
• Chemical exposure — confirm the specific fluids, cleaning agents, and environmental conditions the part will contact.
• Temperature — confirm service temperature range; PU is not suitable for continuous elevated-temperature service.
• Wet or submerged service — confirm if hydrolysis-resistant grade is needed for permanently wet applications.
• Form — PU is available as sheet for cutting to profile or as moulded components; confirm which is appropriate.

How does PU (Polyurethane) compare?

• Natural Rubber (NR)

  Natural rubber has excellent dynamic properties (resilience, fatigue resistance) but lower abrasion resistance than PU. NR is better for dynamic sealing and vibration damping; PU is better for wear resistance.

• NBR (Nitrile Rubber) →

  NBR is specifically better in oil and fuel contact at elevated temperatures. PU handles oils but may not match NBR in all high-temperature oil environments.