A rubber scraper wears out in two weeks, a polyamide sleeve cracks under the first impact load, and a steel part rusts and transmits vibration through the entire assembly — this is the typical result of choosing the wrong material. Cast polyurethane solves these problems with abrasion resistance several times higher than standard rubber and a hardness range from 50 Shore A to 70 Shore D. This article explains what cast polyurethane is, how it is structured and where it genuinely outperforms alternatives in industrial conditions.
What Is Cast Polyurethane and How Is It Made
Cast polyurethane is a synthetic elastomer formed by reacting isocyanate with polyol when poured into a prepared mould. The free-casting process produces complex-geometry parts with no restrictions on layer thickness or shape, and the polymer composition is adjusted to the specific application — from flexible seals to rigid liner plates.
Unlike rubber, which is vulcanised under pressure, polyurethane is cast into a mould at atmospheric pressure. This enables non-standard parts reinforced with metal or with profiled surfaces, without expensive press tooling. Free casting is the core technology at TIMOL: it allows rapid production of both standard and unique parts to a customer’s drawing.
After curing, the polymer combines properties of rubber and rigid plastic. Depending on the formulation the same material can be soft and elastic (for seals and dampers) or rigid and abrasion-resistant (for rollers, plates and bushings). This makes cast polyurethane unique — it has no direct analogue among rubber grades or engineering plastics.
Physical and Mechanical Properties of TIMOL Polyurethane
The main technical advantage of cast polyurethane is abrasion resistance. Wear by DIN 53516 standard is 38-39 mm³ — 2 to 5 times better than various rubber grades. Tensile strength of 39-87 MPa allows sustained impact loading without cracking. Rebound elasticity of 34-61% provides damping under dynamic loads.
The working temperature range from -60 to +100 °C is one of the widest among elastomers. Polyurethane retains flexibility and resilience in freezer conditions and does not soften when heated within the stated range — fundamentally different from natural rubber (upper limit +70 °C) or SBR rubber (+80 °C).
Hardness is adjustable from 50 Shore A (soft seals, flexible gaskets) to 70 Shore D (rigid rollers, liner plates, bushings). Density of 1.05-1.25 g/cm³ is six to seven times lower than steel, significantly reducing part weight and simplifying installation.
Comparison of Polyurethane with Rubber, Polyamide and Steel
| Material | Abrasion DIN 53516, mm³ | Working temp, °C | Hardness | Tensile strength, MPa | Density, g/cm³ |
|---|---|---|---|---|---|
| Cast polyurethane (TIMOL) | 38-39 | -60…+100 | 85A-95A | 39-87 | 1.05-1.25 |
| SBR rubber | 100-200 | -40…+80 | 40A - 80A | 8-20 | 0.94-1.10 |
| NBR rubber | 80-150 | -30…+100 | 40A - 90A | 10-25 | 1.00-1.30 |
| Polyamide PA6/PA66 | 30-90 | -40…+100 | 75D - 85D | 60-85 | 1.13-1.15 |
| Carbon steel | — | -40…+500 | 120-250 HB | 370-700 | 7.70-7.90 |
Polyurethane abrasion by DIN 53516 is 38-39 mm³ versus 100-200 mm³ for SBR rubber — rubber wears 2 to 5 times faster under identical conditions. Polyamide looks competitive on abrasion (30-90 mm³) but is brittle under impact and absorbs moisture up to 8%, changing part dimensions. Steel has the highest tensile strength but is six to seven times heavier, corrodes and does not damp vibration.
Engineer’s tip: if the assembly involves impact abrasion, do not judge material by hardness alone. Polyurethane at 60-70 Shore D absorbs the blow thanks to its elasticity, while polyamide of equal hardness (75-85D) will crack on the first sharp load. Before ordering, clarify the wear type — abrasive or impact — as this defines the optimal hardness range.
Applications of Cast Polyurethane: 12 Industrial Sectors
Cast polyurethane covers 12 industrial sectors where parts are exposed to abrasive wear, impact loads or aggressive media. Key sectors include mining, metallurgy, mechanical engineering, oil and gas, railway transport, agriculture, ports, pulp and paper, food processing, printing, tube rolling and light industry.
In real assemblies polyurethane is used for lining buckets, drums and chutes; producing scrapers, rollers, bandages and seals; manufacturing vibrating screen decks, plates and sheets protecting metal surfaces from abrasion. In food and paper industries it is valued for chemical inertness; in printing for dimensional accuracy and stability under cyclic load. Browse the full product range in the polyurethane product catalogue.
Selecting Hardness and Profile for a Polyurethane Part
Hardness defines the balance between flexibility, abrasion resistance and damping properties. For flexible seals, gaskets and shaft seals, 50-70 Shore A provides elastic deformation under pressure with full shape recovery. For linings, plates and scrapers working in abrasive, the upper part of the Shore A range, 80-95 Shore A, is chosen: a firm yet resilient material holds wear better than rigid Shore D, which chips under abrasion.
Part profile and dimensions are determined from a drawing or sample. Free casting reproduces any shape — from thin overlays to massive reinforced plates and rollers. Layer thickness matters: too thin wears out quickly under intense abrasion; excessively thick adds cost without proportional gain in service life. Learn more about our manufacturing services on the services page.
Installation and Maintenance of Polyurethane Products
Bushings and rollers are fitted to shafts with an interference fit; scrapers and plates are bolted or bonded after metal surface preparation (sandblasting followed by degreasing). For seals, precise fit dimensions are critical for leak-tightness and stable operation.
Polyurethane products are much lighter than steel equivalents, so installation and removal are faster with less labour. Detailed surface preparation and installation guidelines are in the reference information section of the TIMOL website.
How to Order a Polyurethane Part from TIMOL
Ordering starts with a technical specification: customer supplies a drawing or sample, describes operating conditions — temperature, load, environment, wear type. TIMOL engineers analyse the assembly, select the polyurethane composition by hardness and strength, and propose the optimal part design. Free casting allows rapid changes and production of single parts or batch quantities. To submit an enquiry or receive consultation, use the TIMOL contact page.