A leading supplier reports that mattress companies have been selling latex rubber mattresses since the 1920’s. Adding that, “these mattresses were more expensive than innersprings, but lasted considerably longer therefore giving them a better ‘cost per year’ value. Today’s manufacturing processes have allowed suppliers and manufacturers alike to offer new specialty choices. Latex rubber cores and/or toppers are now being used as either the main component or as comfort layers in most top brands in the United States.
It goes without saying that retail sales associates have sold mattresses with latex rubber for years, but if you asked many the basic details and advantages most cannot discuss the basics. The fact is, latex rubber offers various levels of soft and resiliency. This is most simply understood as the gentle supporting push back with a velvet touch. Research shows there are millions looking for alternatives to innersprings. Some may prefer the pro-active (as opposed to re-active) resilient, yet soft push-back that comes from foam rubber.
Latex rubber suppliers claim that any latex mattress, regardless of the process used to make it or the chemical and physical composition of the rubber, offers a sleep surface with unsurpassed comfort and restorative sleep. To help retailers better understand the different types of latex rubber and the way it is formed, we start by outlining the differences between Natural and Synthetic and then move on to the three different formation processes—Talalay, Dunlap and Continuous.
NATURAL VERSUS SYNTHETIC
Natural rubber latex is a polymer that comes in the form of juice (sap or milk) of the tropical rubber tree. Typically grown on plantations in tropical areas such as, Malaysia, Sri Lanka, rubber trees provide a bio-based, truly renewable material that, when the weather permits and it is planted and harvested correctly, can create a vulcanized rubber foam. One plantation recently earned USDA organic certification of its rubber tree sap. Synthetic (Polysyrene-butadiene) rubber latex is a polymer produced from styrene and butadiene and specifically designed to mimic natural rubber. This polymer is produced in water on both batch and continuous production lines. After being polymerized this synthetic latex is stripped of residual reactants and then concentrated for commercial use.
Depending upon the supplier or the marketer, each of these offers superior attributes. Supporters of natural cite the touch and feel, as well as the ecological and renewable nature of the product as superior while, synthetic advocates see consistency of materials, stability, performance, and reliability of source material as a better option.
While the debate of natural to synthetic material continues, one supplier finds that no matter the breakdown, latex rubber is superior to competitive technologies in terms of providing high performance mattress components. This source points out that depending upon the requirements of a mattress manufacturer, latex rubber can be made along a continuum from 95% all-natural rubber composition to a nearly total synthetic rubber that is not polyurethane foam. Another major supplier speculates that 85% of all latex foam rubber in the bedding industry is a blend of natural and synthetic latex. They believe that the correct blend “offers the best of nature and man-made ingredients.”
TALALAY VERSUS DUNLOP
There is considerable debate between latex rubber suppliers over which formation process is the better choice. In the Talalay Process the specified latex compound (natural or synthetic) is injected with air and frothed up to form foam. From there, an aluminum mold is filled part way with the now pourable foam. The mold is sealed and the pressure inside reduced. This decrease in pressure causes air bubbles to expand and the foam redistributes itself evenly causing a uniform density and filling the mold. From here the foam is then frozen inside the mold before carbon dioxide is added to stabilize the rubber in the latex and the foam is heated to vulcanize the rubber. After it cools, the mold is opened and the newly created foam block washed and dried.
During the Dunlop (or standard) Process, the specified latex compound (again natural or synthetic) is injected with air and a gelling agent then frothed to form foam. The gelling agent destabilizes the foam and when the foam is poured, it completely fills the mold. With the mold closed, the foam settles as the rubber destabilizes and the rubber particles coalesce forming a continuous open-cell, solid block of foam rubber. The foam is heated to vulcanize it, then cooled, removed from the molded and washed and dried.
The latex industry’s most common method of production is the Continuous Process. In the continuous process production method, the latex is poured, cured, washed, and dried on a long belt without a mold. This eliminates the air extraction and freezing stages creating, what some argue, a denser latex rubber. This process results in a firm, consistent product. The continuous process, a simplified version of the Dunlop process, produces latex used primarily in mattress base cores, as an economical mattress topper and as a comfort layer in mattress quilting. Within each process the final step includes washing and drying the latex, this increases performance and extends durability. Each of these processes offers a distinct advantage. One states that the Talalay provides a unique feel, uniformity and the ability to reach low densities for easier manufacturing and the advantages of the Dunlop process are shorter production times. Others state favor the density, gauge and consistent feel of the Continuous process.
These are the key variables involved with the manufacturing of latex rubber for mattresses and pillows. Retailers and manufacturers can only gain by learning more about the various technologies and materials used in today’s sleep solutions.
For more information, visit these resources: www.latexco.com, www.latexinternational.com, www.latexgreen.com, nf.arpicorubber.com, www.sapsalatex.com/UK/About-latex/, www.vitafoam.co.uk/latex.html, en.wikipedia.org/wiki/Latex