by Dean Trumbell [Guest Blogger] October 15, 2017 3 min read
The new kid on the block vs. the original specialty bedding product. Interesting question let’s get started to see if we can uncover any definitive answers. Perhaps the best way to do that is to look at each foam type’s unique characteristics. Latex foam is derived from either all-natural latex rubber extracted from rubber trees grown mainly in Southeast Asia or from what is known as synthetic rubber SBR (styrene butadiene rubber) or a combination of both (commonly known as a blended latex). The rubber is generally placed in mold and then taken through a process known as vulcanization which turns the liquid latex into a solid core product. There a two types of vulcanization process, Dunlop and Talalay. Talalay process introduces extreme heat and extreme cold which homogenizes the cell structure which tends to offer a more consistent structure without voids which appear in the form of large air holes in the solid foam core itself. Dunlop process does not use extreme heat and extreme cold in the vulcanization process. Dunlop process is generally thought to be a less technologically sophisticated process, however improvements in this process have also come forward to offer vastly better latex core products than were once produced not that long ago. Generally, the Talalay process produces softer ILDs for surface comfort, while Dunlop produces excellent support layers for deep down support. Latex can be used in all three applications in what I think makes a great mattress. Comfort layers (usually the top 2-3” of the mattress), transitional layers (the middle 2-3” of the mattress) and the support layers (usually the base 6” layer). By using this formula, you can come up with all kinds of interesting feels and options (such as exchanging individual layers without changing the entire mattress). The main characteristic of latex in my opinion is resilience or fast recovery. If you have ever bounced a hard rubber ball, you have observed resilience when the ball bounces up off a hard surface. Latex is denser than most common urethane foams therefore giving great durability to its main characteristic of resilience. In other words, it keeps pushing back for years and years with little noticeable change.
Ok, let’s take a look at the new kid on the block commonly known as memory foam. Viscoelastic foam or memory foam is completely chemically derived. Viscoelastic foam has completely the opposite characteristic of latex (fast resilience). Memory foam has very slow recovery characteristics. I would compare it to a marsh mellow, if you compress it flat it takes a long time for it to return to its original shape. It is an excellent foam type to directly mold to the shape of your body. That is why it is primarily used as a comfort layer (top 2-3”) and some cases transitional layers (middle 2-3”). However, it should never be used for support layers. If too much memory foam is used in a mattress, you get the sensation of falling into a bottomless pit, it just never reaches up to support you. There are many densities and ILDs offered in memory foams. The sweet spot for me lies in between 4 and 5 lb. density with ILDs in the 8-12 range. Again, the higher densities tend to offer better durability over time. Densities below 3 lb. offer very little of the true memory foam feel. However, we are seeing memory foams now being offered even below 2 lb. density, which only offers a story without a result. Memory foam was originally thought to sleep hot due to its closed cell structure, now memory foams are being produced with more open cell structures which offer better surface airflow without giving up much of the slow recovery feel.
And now for my opinion…I love latex for all the aforementioned reasons and will never consider sleeping on a memory foam bed. I feel that memory foam is over hyped for its pressure relieving abilities. Once I compress the initial surface layer of memory foam, I feel like I hit hard spots which in fact causes it to lose pressure relief. The other characteristic that I failed to mention about memory foam is that it is very temperature sensitive and tends to soften up once it is affected by your body temperature. I notice none of this with latex. As for pressure relieving, latex in lower ILDs used in the comfort layer of a mattress, compress but gently pushed back offering superior surface pressure relief, there is simply nothing like it as far as I am concerned.