A scraper on a confectionery-line conveyor wears out within a few weeks, and along with the rubber crumb, something that should not be there ends up in the product. A metal screw guide slides over grain, leaves burrs, and gradually contaminates the flow. Polyurethane solves both problems at once: it is many times more wear resistant than rubber and does not transfer foreign contaminants to the product. This article explains exactly where cast polyurethane replaces rubber and metal in food production and how to select a part for a specific line.
Why Polyurethane Is Displacing Rubber and Metal on Food Lines
The main reason is simple: polyurethane combines wear resistance, hygiene, and oil resistance, which none of the traditional materials offers on its own. Rubber wears quickly and crumbles, metal contaminates the flow with wear particles and rust, rigid plastics crack under impact. Cast polyurethane from TIMOL outlasts standard rubber by roughly 2-5 times in wear resistance while keeping its elasticity and a clean contact surface.
For food production this is a direct economic benefit. Every line stoppage to replace a worn part means lost hours and the risk of idling the whole section. A polyurethane part runs longer between replacements, and its smooth, non-porous surface does not absorb grease or become a breeding ground for microorganisms. An operating temperature from -60 to +100 °C covers almost every process: from freezer chambers to lines with warm sanitary cleaning.
Hygienic Properties: Product Contact Without Risk
Cast polyurethane does not transfer odour or taste to the product and contains no volatile toxic components that could migrate into food. The surface of the part is dense and non-porous, so product residue does not linger on it, and cleaning requires no aggressive agents. This is critical on lines where the grade of the raw material depends on the cleanliness of the contact elements.
The material is not subject to mould or fungus, does not corrode, and does not leave stains on the product as metal can. Fine dust and crumb do not stick to conveyor and screw coatings, and the low coefficient of friction reduces grain damage during transport, preserving its marketable appearance. This is why polyurethane is widely used in the grain, confectionery, flour-milling, and processing sectors, parts for which the factory groups into separate application industries.
Comparison of Materials for Food Equipment
A direct comparison of the numbers shows why polyurethane wins where wear and cleanliness requirements combine. NBR rubber still holds up against oil but wears quickly; UHMW-PE has low friction but is not elastic and deforms under load.
| Property | TIMOL Polyurethane | NBR Rubber | UHMW-PE |
|---|---|---|---|
| Abrasion DIN 53516, mm³ | 38-39 | 80-150 | 15-30 |
| Operating temperature, °C | -60…+100 | -30…+100 | -200…+80 |
| Tensile strength, MPa | 39-87 | 10-25 | 17-45 |
| Density, g/cm³ | 1.05-1.25 | 1.0-1.3 | 0.93-0.95 |
| Rebound elasticity, % | 34-61 | 20-45 | 5-10 |
| Oil resistance | excellent | good | good |
| Impact resilience | high | medium | low |
In abrasion, polyurethane and UHMW-PE are close, but polyurethane is far more elastic: 34-61 % rebound versus 5-10 % for polyethylene. This means a polyurethane part absorbs impacts and returns to shape, whereas UHMW-PE gradually deforms. Compared with NBR rubber, polyurethane wears 2-4 times more slowly while offering better tensile strength.
Exactly Where Polyurethane Works in Food Production
Most often polyurethane is fitted where metal or rubber meets a moving abrasive flow. Scrapers for cleaning sticky product from conveyor belts remove the buildup without scratching the belt or leaving crumb. Linings for hoppers, gravity chutes, and troughs reduce the friction of bulk product against the walls, while the elastic coating dampens grain impact and stops material from sticking in tight spots.
Polyurethane flights and coatings for conveying screws reduce grain damage and extend the assembly’s service life. Rollers, sprockets, and guides run more quietly than metal counterparts thanks to the material’s ability to dampen vibration. Such parts are mostly mounted mechanically: roller coatings are fitted as a ring, lining elements are secured with bolts or flanges with free play so that metal and polyurethane expand independently and the coating does not tear away. Ready-made standard items for these assemblies are collected in the catalogue of polyurethane products.
A separate class of parts is the seals and shock-absorbing elements of packaging and filling machines. Here polyurethane is valued for its combination of resilience and service life: the part holds its geometry under cyclic load and does not crumble, so it does not contaminate the line with wear fragments. In washing equipment and assemblies with frequent sanitation, polyurethane withstands cycles of contact with warm water and cleaning solutions without swelling, unlike many rubbers that gradually lose their shape. This directly affects the dimensional stability of the part over a shift and the frequency of unplanned stoppages.
How to Choose Hardness and Order a Part for the Line
The choice of hardness determines how the part will behave under load. For scrapers and seals, material in the 80-95 Shore A range is usually taken: it is resilient enough to fit tightly against the surface. For rollers and guides under heavy load, harder grades up to 70 Shore D are used. Overall, the hardness range of TIMOL polyurethane spans from 50 Shore A to 70 Shore D, which allows a material to be selected for almost any assembly.
TIMOL engineer’s tip: before ordering a replacement part, give the process engineer not only the dimensions but also a description of the conditions: type of product, temperature, washing regime, and nature of the load. Often the cause of rapid wear in a rubber counterpart is insufficient hardness or poor geometry, not the material itself. Correctly selected hardness delivers a greater gain in service life than simply switching to a more expensive material.
The order is manufactured using the open-casting technology, which allows a part to be cast to a specific dimension or drawing without costly tooling. The technical properties of the material and its application regimes are described in the reference information section.
Conclusion: Cleanliness, Service Life, and Replacement Economics
Polyurethane in food production solves three tasks at once: it is many times more wear resistant than rubber, does not contaminate the product like metal, and dampens impact and vibration, which rigid plastics cannot do. The operating range of -60…+100 °C and hardness from 50 Shore A to 70 Shore D cover most lines, while the open-casting technology allows a part to be made for your assembly. To select a material and calculate the replacement of a worn part, contact a process engineer through the TIMOL factory contacts.