How are Memory Foam Mattresses Made?
These pieces of memory foam may seem simple, but there’s actually a fair amount of complex science at work.
The basis for memory foam is a polymer made of polyurethane. First developed in the 1950s, this foam is produced by combining water and hydrocarbons or halocarbons into a polyurethane mixture.
Different isocyanates and reacting agents are added to the polymer to create modern memory foam to alter its density and viscosity. The mixture is whipped into a froth and poured into a mold, where a heat reaction causes it to bubble and produce foam.
This mixture is infused with gas or blowing agents or vacuum-sealed to create an open-cell matrix. This matrix is what gives memory foam its ability to bounce back after compression. The polymer-to-air ratio determines the product’s density and how well it responds to body heat and pressure.
The foam is cooled, heated again, and left to cure for several hours or a few days. After curing, the foam is no longer reactive. It is rinsed and inspected before being cut into a mattress.
Different Types of Memory Foam
Used to produce a consistently plush, soft mattress, there are four main varieties of memory foam: traditional, open-cell, gel-infused, and plant-based.
Traditional iterations are made with petroleum-based products. These are usually the easiest to produce and the least expensive. They also tend to absorb heat more than other foam options.
Open-cell memory foam has the same essential components as its traditional counterpart but with a different structure. It contains pockets, or cells, that promote ventilation and airflow to release heat.
The first open-cell mattresses were significantly less dense and thus less supportive. However, manufacturers have since found ways to address that problem.
Yost developed gel-infused memory foam in 2006 as a means to reduce heat retention. However, it didn’t become popular until 2011.
Manufacturers now have a few ways to infuse gel into the foam. Some pour liquid gel on the top or bottom of the foam layer to create a barrier between layers. Others infuse the foam with gel beads to produce a cooling effect. The cooling gel is made with thermal or “phase-changing” materials. If you’re looking for a memory foam mattress that will help you sleep cooler, a gel mattress may be right for you.
A fourth variety is plant-based memory foam, which replaces petroleum-based ingredients with those made from plant-derived oils. These are usually favored for their eco-friendliness, but some manufacturers claim they can also improve breathability and reduce heat retention. These foams may be free of chemicals, such as CFCs, phthalates, PBDEs, and formaldehyde, often present in traditional foams.
The Pros and Cons of Memory Foam Mattresses
The best memory foam mattresses can provide a host of benefits, but they aren’t for everyone. Here are some pros and cons to consider:
Pros of Memory Foam
Body-contouring and pressure relief are memory foam’s hallmark features. The foam responds to your body temperature and pressure, conforming to your unique shape. This means less strain on areas like the neck, hips, and shoulders. Putting excessive stress on these areas can cause discomfort and sleep difficulties.
People with arthritis or joint pain may find memory foam especially beneficial for its pressure relief.
Sufficient spinal support is crucial in a mattress. Without it, you’re more likely to experience aches, pains, and stiffness during the night and when getting up in the morning. This is particularly true for anyone with musculoskeletal conditions or chronic pain. Memory foam, which is typically medium-firm, provides the necessary support to keep the spine in alignment.
Less Motion Transfer & Noise
If you sleep with a partner or child, you might have difficulty getting adequate shuteye if they tend to toss and turn. Memory foam isolates motion well, meaning you won’t be stirred when your partner shifts positions or your child climbs into bed in the middle of the night.
Similarly, memory foam can be quieter than some beds, like innerspring, which tend to groan and squeak when someone moves or gets up.
Cons of Memory Foam
The biggest complaint sleepers have about memory foam is its tendency to absorb heat. It’s no surprise since the material is specifically designed to respond to body heat, but it can be uncomfortable, particularly if you tend to sleep hot already, and may disrupt your sleep. The good news is many manufacturers have combatted this issue with solutions like cooling materials and built-in air channels for air circulation and temperature regulation. You can also buy cooling toppers or pads to accompany a traditional memory foam mattress.
Some people appreciate the feeling of sinking into bed, but others feel constricted by the layers of foam, especially couples during sex. Less resilient mattresses may also consistently have deep indentations where the sleeper lies, making it a less ideal choice for people who tend to switch up sleeping positions. Almost all memory foam mattress will produce this effect, but some manufacturers offer mattresses with firmness levels designed to counteract this effect.
In the early days, memory foam, like many products, was produced with potentially harmful chemicals, such as formaldehyde. They also give off small amounts of volatile organic compounds (VOCs) from polyurethane foam and other chemicals found in flame retardants.
Nowadays, mattresses are made with far fewer harsh chemicals. However, memory foam is not as eco-friendly as some materials like natural latex.
What to Look for in a Memory Foam Mattress
The main feature to look for in a memory foam mattress is cooling technology. Gel and open-cell varieties are generally the best memory foam mattresses because they tend to run cooler. Many manufacturers utilize additional technologies and cooling layers or air channels, to provide enhanced temperature regulation. Whatever the method, look for memory foam mattresses that boast superior cooling properties.
If you’re concerned about the chemicals used in memory foam, take a look at the specific materials used in the mattress’s production, and look for “non-toxic” options. Most high-quality manufacturers, however, have eliminated harmful chemicals from their process and voluntarily submit their materials for neutral, third-party testing to ensure that their products are safe to use. The Federal Trade Commision has even cracked down on companies falsely claiming to be free of VOCs.
If supportiveness, including edge support, is of particular concern, be sure to read reviews to ensure the mattress provides sufficient support. While memory foam typically gets good marks in this area, some lower-quality products may not hold up and will sag over time.