Polyurethanes can be hard and brittle or soft and elastic, depending on the manufacturing process used.
The elastomers in particular have a comparatively high tear resistance.
In an expanded form, polyurethane is known as a permanently elastic soft foam (e.g. for sports shoe soles) or as a rigid installation foam. Household sponges made from soft PUR foam. Polyurethane can be easily used to make foams. The special characteristic of PUR foams is that they available both in a workable for for construction sites say or as semi-finished goods (foam in cut form), as well as being able to be produced on site from liquid components or place in or on industrial parts (foaming in-situ, formed-in-place foam, FIPFG). Soft PUR foams are used for extremely diverse purposes, but above all as upholstery material, i.e. for mattresses or seats for furniture or car seats, as carpet backing material, for lining textiles, as cleaning sponges or as filter material.
PUR soft foams are mostly multicellular (open-celled) and are available with a wide range of hardnesses and densities.