Mattress Construction Blog Series – Memory Foam

History of Memory Foam

In 1966 Ames Research Center, under contract with NASA developed a new foam that would handle abuse at higher gravitational forces and stay comfortable (tolerable) for astronauts and pilots on higher speed aircraft and developing space vehicles.  This material was referred to as “slow spring back foam” and was primarily a polyurethane foam with additional chemicals to increase the viscosity of the foam, slow the rebound of the formation. 

This foam softened with normal body temperatures and would conform and mold to body impressions quickly.  One of the significant contributing scientists, Charles Yost, began calling it Temper foam due to this property.  

This earlier version of memory foam was adopted by the medical field for use in X-Ray beds for its comfort and warming feel.  Upon seeing pluses in its conformity to human body impressions, it was then used in wheelchair cushions and beds for bedridden patients.  Research had shown that memory foam eliminated bed sores and contact bruising due to its conforming properties.  The heat retention property was also seen as a plus and help in healing for many bed-ridden patients.  

It was not until the early 1990’s that memory foam was used in consumer mattresses.  By then, Tempur-Pedic had been developing mattresses for the medical field for several years and had developed a better longer lasting version of memory foam for the consumer market.  Consumers adopted the new technology quickly, loving the body molding properties and the significant reduction in body pressure points on these new mattresses.  Issues began though when consumers tired of the heat retaining properties of memory foam.  These new beds were far from perfect for the hotter sleeping public.  

Other companies began to develop their versions of memory foam and at much cheaper costs.  The original manufacturer had been manufacturing in the medical field and had developed foams at costs associated with the medical demands and standards, these cheaper developed foams were quite competitive and caught up quickly in sales.

By 2006 a third generation of memory foam had been developed with gel infused memory foam.  This newer version reduced heat significantly.  Other materials follow suit quickly, gel capsules which would change states from solid to liquid when faced with body heat, phase change materials which would funnel heat away from the body.  Materials such as Aloe, Soy, and even Charcoal were infused in memory foam for different property additions like odor reduction, heat wicking, and other wanted reactions.

Memory Foam Differences

Not all memory foam is the same.  Older versions suffered from heat retention, making it hard to sleep on warmer nights.  

Memory foam is measured in Density and IFD (Indentation Force Deflection).  Density refers to weight per pounds per cubic foot.  IFD refers to force (in pounds) necessary to make a 1-inch dent in a measured sample of memory foam.  

Both measurements are accurate to a point. However, differences in Density can throw off IFD measurements when IFD is being used as a measurement for firmness or softness of memory foam.  Basic knowledge of memory foam averages is a good gauge for knowing quality.  Memory foam averages between 1.5lb/ft3 to 8lb/ft3.  A good density memory foam mattress will contain a 5lb/ft3 memory foam layer.  Generally, memory foam mattress toppers weigh in with densities of 3 to 4lb/ft3.  

A high-density mattress will have better compression ratings over the life of the bedding. A lower-density one will have a slightly shorter life due to the compression that takes place after repeated use. Keep these ratings in mind when shopping for an all memory foam mattress.

Mattress Construction

Memory foam mattress construction is based on different layers for comfort.  A base layer of high-density foam is used for support purposes on the lowest layer of any mattress.  Next layers can consist of several different densities of memory foams, memory foam hybrid mixes, latex foams, and many other comfort layers.  

Keep in mind the term “Memory Foam Mattress” does not mean that the entire mattress is constructed of memory foam.  Memory foam mattresses require a strong base foam for support of its body molding effects. Expect anywhere for 2 to 4 inches of different combinations of memory foam densities in most mattresses.  Using such combinations allows for customization of soft to firm feel of the mattresses.  

Conclusion

Memory foam is an excellent comfort layer in any mattress.  An important note must be made of densities used though, as this determines the longevity of the foam and the mattress itself.  

Many companies have marketed their memory foam mattresses as quality mattresses for the consumer looking for cheaper pricing.  While they can provide a very low price, they also are providing a mattress which may cost you much more in the long run.  Consider replacement would be quicker, estimate 3 to 4-year lifespan in a “value” online mattress.  Consider backaches due to longevity issues of cheaper foam.  Consider most that you are buying a mattress that you will be sleeping on for 7-8 hours a night and you haven’t even had a chance to feel it.  

Shop smart, research your products, deal with a reputable team, and enjoy the experience of shopping for your new bed.  At Sleep Well we are fond of saying that there is no time limit placed on you when you are laying on one of our beds, just lay there and get to feel if this mattress is the right one for you.  Rest assured, we’ve research our memory foam densities, and we are quite familiar with our manufacturers.

Please read through our other blogs on mattress comfort layers for further information on your next sleep purchase!  If you have any questions or comments, please feel free to leave them in the comment box below.

*sources – Wikipedia -https://en.wikipedia.org/wiki/Memory_foam, PFA.org -http://www.pfa.org/intouch/new_pdf/hr_IntouchV1.2.pdf