Polyurethane is a type of plastic – more specifically, a group of polymers. It’s a chemical substance that’s essential to several Habasit products and to many of the objects that we see and use in everyday life.
Polyurethane is a highly flexible material – it has a variety of useful properties, including great durability to both heat and wear. It is easy to color, can be combined with other materials – such as glass and many kinds of additives, and can be produced in different forms and textures. Clothes, shoes, floors, sponges, paint, furniture and insulation are just some of its uses. One reason for this is that polyurethane can be hard or soft, thus making it suitable for a wide range of products.
Polyester based TPU and its properties
Thermoplastic urethane – TPU – comes in two variants: polyester and polyether based. The former is highly flexible (even at low temperatures), highly durable, and highly resistant to oil and grease. Polyester based TPU is almost hydrophobic in nature, effectively repelling grease, oil and other liquids.
As a result, polyester conveyor belts are widely used throughout the food industry in particular. In addition to conveyor belts, Habasit uses polyester based TPU in timing belts and round belts. Profiles and cleats are easy to apply to all types of TPU belts.
Polyether based TPU and its properties
Polyether based TPU absorbs water, although only in miniscule amounts. The only consequence of this is the possibility of a reversible growth in dimension. Polyether base TPU is somewhat less abrasion resistant when compared with polyester based TPU, but it’s also more resistant to heat and chemicals, making it easy to clean.
As is the case with polyester based TPU’s, conveyor belts with a polyether based TPU top layer are popular in a variety of industries, especially the food industry. Unlike other Habasit conveyor belts, our Cleandrive monolithic belts made from polyether based TPU are completely cast in plastic without any fabric layers or coating. Aramid threads inside the cast prevent the belt from expanding when absorbing liquids. Profiles and cleats are easy to apply to polyether based TPU belts as well.
Cross-linked polyurethane is less flexible than thermoplastic polyurethane – but very durable
An exception to the far-reaching flexibility of thermoplastic urethane is cross-linked polyurethane or PU. This is a type of urethane that has been chemically treated to be particularly strong and resilient. As it is not thermoplastic, it will not mold, melt, or otherwise be affected unless by extreme heat or pressure.
PU is often used as a thin top layer on conveyor belts that transport very heavy, hard and/or sharp products, and in facilities where the physical impact of the product on the conveyor belt is very forceful. Cross-linked PU can withstand temperatures of up to 250 °C.
Choosing the right kind of polyurethane belt for your application
Before ordering or installing a new belt for your application or conveyor, it’s important to make sure that the belt can handle the conditions in your facility. If this is not done properly, it could lead to damage not just of the belt, but to products and other equipment as well.
For more information about our belts and their properties, contact your local Habasit office or visit the Habasit website. You’ll also find plenty of other interesting articles here on the Habasit Expert Blog.