Do you ever wonder what is in your mattress? If so, you are not alone. Most consumers want a non-toxic mattress. Many of these want a bed that is chemical free, fiberglass free, and natural and/or organic. Some even want it metal free. Then there are others who are fine with synthetic materials – as long as they are not generally considered toxic.
List of Ingredients
The materials in mattresses can be put into several categories: Fibers, Fire Resistance, Temperature Control, Cushioning, and Support.
While fibers are used in cover materials, they are also used in other parts of a mattress, such as padding, liners, pockets, etc. Both natural and synthetic fibers are common in mattresses. Some are natural-synthetic blends. Here are some of the most used fibers.
Cotton – This is the most common plant fiber. These fibers from the seed pods of Gossypium species have been used in fabrics for thousands of years, beginning in Peru and India. Cotton batting was used for support and cushioning (and cotton fabric as the cover) in early commercial mattresses. The most common bedding uses today are in mattress covers, pillow covers, and sheets. All-cotton mattresses are still being made, such as the Organic Cotton Mattress by White Lotus Home.
Wool – The curly hair of sheep has also been used for thousands of years. Today, wool is used in mattress cover fabrics, top-side cushioning, and fire resistance. The Wool Bed Company makes all-wool mattresses.
Polyester – This is the most common synthetic fiber used in mattresses. It is often in fabric blends, along with cotton and spandex. It mostly contributes durability.
Rayon (Viscose) – This is reconstituted cellulose, which is extracted from wood pulp, liquefied, and extruded as filaments which are spun into threads. A popular wood source for fabric rayon is bamboo.
Lycra (Spandex) – This synthetic fiber is extremely elastic as well as strong. Very small amounts in the thread make it very stretchy.
Linen – Bast fibers are extracted from flax stems by crushing, soaking, and retting (letting softer materials decompose). This process has been used for thousands of years. Linen is a luxury fiber, found in more expensive mattresses.
Federal standards require mattresses to have a certain level of resistance to ignition. Mattress manufacturers have developed several means of meeting these standards.
Chemicals – Fire-retardant chemicals – such as Firemaster 550 (isopropylated triphenyl phosphate and triphenyl phosphate), TDCPP (chlorinated tris), and PBDE (pentabrominated diphenyl ether) – had been mixed into polyurethane foam and memory foam to make them flame resistant. However, these chemicals are no longer in foams since they are toxic. Fire protection now uses flame barriers to keep fire away from the foam. Another chemical, boric acid, can be applied to a liner to make it a fire barrier.
Silica-Infused Rayon – Rayon is naturally flammable, since it is cellulose. However, when infused with silica (the main ingredient of glass), it beads up if burned and forms a non-flammable barrier. It is used in a fire sock around the foam. This is inside the cover, so the sleeper does not come in contact with the silica and no silica dust is released.
Wool – Compressed wool is fire-resistant (at least it slows down the burning), so it is used in the fire socks of several beds, such as the Spindle Mattress.
Many ways have been tried to keep memory foam mattresses cool. The most effective means so far has been ventilation and airflow. However, most mattress manufacturers have resorted to other means, such as gel, phase change materials, graphite, copper or titanium, and moisture-wicking fibers.
Gel – Whether as beads or liquid swirls, gel infused into memory foam or other foams does have an initial cooling effect, since it absorbs heat. However, gel can absorb only so much heat. If the foam is also perforated, heat can be conducted to the pores and transferred to air.
Phase Change Materials (PCMs) – A phase-change material keeps the temperature within a designated range. At the top of the range it absorbs a lot of heat and liquefies. At the bottom of the range it releases heat by solidifying. There is a limit to how much PCMs can cool or warm the mattress. Once they are totally liquid, heat is absorbed slowly.
Graphite (“Diamond” Dust) – Ideally, graphite fibers infused into foam conduct heat away from the sleeping surface. However, the heat has to go somewhere.
Copper or Titanium – Metallic gels with copper or titanium are heat conductive. They have the same limitations as non-metallic gel and graphite.
Moisture-Wicking Fibers – Evaporation is how moisture-wicking fibers cool the top of a mattress. Many natural fibers, such as wool, are naturally moisture-wicking. Extruded fibers can be made to wick moisture by configuring their cross section to make channels.
Very few of us want to sleep on a surface as hard as the floor or a wood board. We want some cushioning firm enough to keep us from bottoming out, but with enough give to make it softer than the floor.
Before mattresses, piles of leaves and small branches were used, followed by woven mats placed on the ground, then pillows big enough to stretch out on. Now we have several cushioning materials, such as fiber batting, down and feathers, latex foam, polyurethane foam, latex-like foam, and memory foam.
Fiber Batting – Early commercial mattresses were filled with cotton and/or wool batting, as are a few brands today. Now these two natural cushioning fibers and polyester fiberfill (aka polyfill) are used in mattress. They are often in the top section of a mattress, usually in the quilting.
Down and Feathers – Feathers have been filling pillows and mattresses for a long time, while down was a luxury material until recently. Very few mattresses today are totally filled with down and feathers. It is more often found in toppers and pillows.
Latex (Foam Rubber) – Natural latex foam (aka foam rubber) was first used in mattresses in 1931. Firestone sold synthetic foam rubber mattresses in the 1950s. Latex is often used with memory foam in the same mattress.
Polyurethane Foam (PU) – PU is made using petroleum-derived polyols. Most foam mattress support cores are PU. The padding in most innerspring mattresses and the comfort and transition layers in foam mattresses and hybrids are PU.
Latex-Like Foam – This is PU which has been modified to have the properties of latex. It has replaced latex in the Casper Mattress and several others.
Memory Foam –The first memory foam mattress was introduced in Sweden in 1991 and in the United States and Canada in 1992. It conforms to the sleeper’s contours for pressure relief. Memory foam is made by adding chemicals to polyurethane foam. It is known for off-gassing and for heat build-up.
Several materials are used in the support cores of mattresses, including very firm foam, steel and titanium, wood, and coir.
Very Firm Foam – The support cores of all-foam mattresses are extra firm foam. Polyurethane is the most common support core in foam mattresses it is usually 1.8-lb. density. Some latex mattresses, including those by Spindle and Pure Talalay Bliss, have latex foam cores. A few memory foam mattresses had extremely-firm memory foam cores.
Steel & Titanium – Innerspring coils and micro-coils are made of steel and/or titanium. These metals are also used in box springs, adjustable beds, and bed frames.
Wood – One company has been making and using wooden coils in their mattresses for over 25 years. VitalWood inserts these into their mattresses’ base foams for zoning. Why wood? To avoid metal coils focusing radio waves on the sleepers. VitalWood also uses wood shavings as a base material in some of their mattresses.
Coir – Coconut husk fiber is called coir, but most often this term is used for the fibers soaked in liquid latex and cured. Mattress manufacturers using coir include VitalWood and Palmpring.
When shopping for a mattress, consider what is in it. Which materials do you prefer, and why?