What is HR foam?

HR is the term that defines high resilience polyurethane foam (HR - high resilience) used in rest ambit. 


The HR is a flexible foam that is formed mainly by the chemical reaction of two compounds, a polyol and an isocyanate, but formulating needs and supports multiple variants and additives. This reaction releases a gas (carbon dioxide) which are the bubbles that are formed in the internal structure of the final core.

HR classification

During rest, the criterion used to differentiate the various HR foam is density. 


The density is usually expressed in kilograms per cubic meter (kg/m3). The density is vital because the flexible polyurethane consists of maerial and voids (bubbles generated by the CO2 from the reaction).


The strength of flexible polyurethane is independent of its density. There may be low density foam and firm surface or high-density, soft surface. Therefore terms of "high density" or "low density" don't exist.


On the other hand there is a difference between "firmness" and "support" terms. Firmness is a measurement of the polyurethane surface characteristics. Support is the ability to "push" against a weight whilethe foam in not deformed. The higher density foams prevent the foam from collapsing under the weight of the body in final applications. 


Density is often used to compare the different foams, but only serves as a comparison when talking about foams with the same composition, since different formulas give us different characteristics. In some foams we look for the longest, in other cheaper price, or breathability, insulating ability, ease of shaping or shape, lightness, and so on. 

HR in our rest

HR is used routinely as a complement of viscoelastic mattresses based on providing a firmer base to enhance the effects of memory foam (the viscosity by itself does not provide a sufficiently strong support for our body). 


Although HR is also used as single core mattresses. Mattresses with high firmness, with a great transpirability, aging resistance and resistance to humidity and high temperature high. 


Currently, there is a variation on the conventional HR polyurethane foams. Evotex, presents great progress towards the welfare, comfort and relaxation.