Different designations on the same material
Most ergonomic and orthopedic pillow brands (Royal Rest, Core, Sissel and Tempur) are made of a material called flexible polyurethane foam (PUR), which is a very malleable, flexible material and antibacterial or allergy neutral. The cellular structure of the material relieves more evenly and has a sanitary good life. It is thus well suited for the purpose where special adaptation in design or variations in hardness and weight is required. Other layman’s notes appear, for example, foam plastic in everyday speech.
Difference between memory foam and classic foam
Viscoelastic foam, aka memory foam, reacts on temperature fluctuations where cold makes it firm and warmth makes it soften and give way to pressure easier. High resilient foam (HR), aka classic foam or traditional foam material, react very little to temperature and exert constant equal pressure relieving support.
The hardness of the material
Flexible polyurethane can be manufactured in various hardness/firmness: from super soft to very rigid materials. Both materials, viscoelastic and high density foam, which are manufactured in a continuous foaming process called slabstock production, can vary up to +/- 15% in firmness, even if manufactured from the same slabstock of foam. This can cause up to 30% difference in firmness between individual pillows/mattresses and give rise to a different feeling even when it comes to the same brand and batch.
Aging or yellowing foam material
Polyurethane turns yellow as it is exposed to the sun’s UV light. It has no general effect on the nature of the material in general, but in the long run accelerates the aging process in the material. The aging process consists in the material’s cell structure becoming fragile and stiffer which negatively affects the pressure-relieving function in the long run.
Polyurethane has a high energy content and is suitable for energy recovery when carried out in an approved waste incineration plant.
Antibacterial, allergy neutral and hygiene
Flexible polyurethane, both inert and highly elastic, is an allergy-neutral material used for many skin-prone products in many areas and commonly used in sleep ergonomics such as mattresses and pillows. It is a neutral material where mites or bacteria cannot feed on the material. The material is water-resistant but to a varying degree sensitive in its strength in machine washing as the product itself is subject to mechanical influence (machine) and can be torn in pieces but can in most cases be hand-washed and self-drying.