How Is Memory Foam Made?

The information in this article is for educational purposes only and should not be considered medical advice. [Read our full health disclaimer]

Updated on September 30, 2023

Memory foam is one of the best inventions of the twentieth century. Since NASA first designed it in the 1970s, memory foam has been employed in mattresses, pillows, and even shoes and blankets.

NASA designed memory foam to play the role of a high-tech coating layer for seats that will improve safety for pilots and astronauts due to its shock-absorbing properties. Furthermore, memory foam’s pressure relief and temperature-sensitive properties made it the perfect product for them.

Since memory foam was developed, it has been in various industries, such as the car industry, medical industry, shoe industry, and bedding industry. Memory foam has drastically changed the bedding market in particular as the memory foam mattress became widely popular thanks to its undeniable durability, support, and comfort.

But, the real question is, how is memory foam made? We’ll answer that question and provide you with other interesting facts about memory foam. So, let’s start!

What Is Memory Foam Made Of?

The basic component of memory foam is a polymer, also known as polyurethane, a chemical with large molecules consisting of many small similar subunits that bond together. Polyurethane is an exceptionally common and versatile plastic polymer that’s used for producing a wide range of products and materials. These obviously include mattresses, but also furniture, liquid primers and paints, spray foam, car parts, and insulation.

Memory foam is also known as low-resistance polyurethane foam or viscoelastic polyurethane foam. It’s manufactured by adding various additives and compounds to polyurethane, which change depending on the type of foam that’s being made.

Ultimately, these additives and compounds impact two of the main properties of memory foam: elasticity and viscosity. When it comes to memory foam, “viscous” means that the memory foam takes longer to change shape when it’s under pressure or to transfer energy from one area to another. In this regard, elasticity is the ability of memory foam to contour or stretch but also return to its original shape and size.

The Manufacturing Process of Memory Foam

The memory foam manufacturing process is quite complex and can take up to 8 hours. The process involves mixing polyols, water, isocyanates, and other reactive materials. The most common type of isocyanate, known as diisocyanate, fully dissolves in these highly reactive procedures.

This particular reaction is a process that takes only 5 minutes to complete and results in a liquid-like consistency of the mixture. Afterwards, the resulting liquid is put into molds that make memory foam slabs. This mold mix is dried quite quickly to make the memory foam or memory foam product.

The manufacturing process also involves forcing out air to create the well-known open-cell feature of memory foam, which makes it breathable. 

Then, the memory foam slabs are cooled down, washed, and moved onto conveyor belts. They can be cut into different dimensions and forms of a mattress or other memory foam products.

That being said, polyurethane foam is highly combustible. When it comes in contact with heat, it can burn and cause huge fires of high toxicity. This is why it’s also treated with fire-retardant chemicals such as polybrominated diphenyl ethers (PBDEs) or polybropminated biphenyls (PBBs).

Different mattress manufacturers use different chemicals and formulas, which leads to various properties and densities.

How Does Memory Foam Work?

In the context of mattresses, memory foam uses your body heat to soften and your body weight to mold to your body shape, wrapping you in a relaxing cushion of support. The softest memory foam mattresses consist of several foam layers that vary in thickness and size.

The memory foam mattress firmness is measured in indentation load deflection (ILD). This refers to the bodyweight required to create an indentation on the memory foam mattress.

The density of the memory foam ranges from low (1.5 to 3 pounds or 0.7 to 1.4 kilograms per cubic foot) to medium (4 to 5 pounds or 1.8 to 2.3 kilograms per cubic foot) to high (6 to 8 pounds or 2.7 to 3.6 kilograms per cubic foot). Heavier mattresses have higher memory foam density.

Some memory foam mattresses can weigh more than 100 pounds (45.3 kilograms). Regardless of the mattress weight, the mattress density accounts for the durability, lifespan, and support of the mattress, meaning the denser the mattress, the better. If you’re someone who wants more support from your mattress, then a medium to high-density memory foam mattress is the right choice for you.

Types of Memory Foam

Basically, memory foam comes in three primary types: gel memory foam, open-cell memory foam, and traditional memory foam. Each type of memory foam has its own pros and cons, so let’s learn something more about them.

Traditional Memory Foam

Traditional memory foam is the first type of memory foam that was developed. It’s made from viscoelastic foam. One of the biggest disadvantages of traditional memory foam is the fact that it tends to retain your body heat, making it uncomfortable to sleep on during hot summer nights (or for hot sleepers in general). On the other hand, the next two types of memory foam were designed to resolve this problem.

Open Cell Memory Foam

Open-cell memory foam is made from the same substances as traditional memory foam, but it has a different internal structure. Open-cell structure memory foam has internal pockets, which are open cells that provide better airflow and ventilation throughout your mattress. That, in turn, helps to keep heat away from your body.

Basically, open-cell memory foam mattresses have far less density, which affects the firmness of your mattress and makes it feel less supportive.

Gel Memory Foam

Gel memory foam, also known as gel-infused memory foam, is a type of memory foam that has been pumped full of gel and has two different types. 

Gel memory foam mattresses tend to have higher density due to the gel microbeads that are used in gel memory foam. However, these gel microbeads can cause your memory foam mattress to degrade faster.

Advantages of Memory Foam Mattresses

In a nutshell, the type of mattress you’ll choose depends only on your preferences; some of you prefer a softer mattress while others prefer a firm one. Memory foam mattresses, in particular, tend to be denser and conform to the shape of your body. Here are some of their advantages:

  • Conforms to your body. This is perfect for various sleep positions because the top-layer memory foam of the sleeping surface cradles your natural body curves and offers excellent pressure point relief, which is good for back pain. 
  • Reduces motion transfer. Since memory foam conforms to your body shape, it sort of creates a personal sleep zone, as opposed to natural latex mattresses, which tend to be bouncier. This helps to prevent motion transfer when sleeping with a partner. 
  • Common allergen resistance. Memory foam mattresses are considered to be generally hypoallergenic, as they tend to resist common allergens such as dust mites, allowing you to breathe better and get that good night’s sleep you’ve been craving.

Disadvantages of Memory Foam Mattresses

Just like all the other mattresses, memory foam mattresses have their own downsides. Here are some of them:

  • Heavier. Because of their high density, mattresses made of memory foam can be quite heavier than other types of mattresses. This makes a memory foam mattress harder to move from one place to another.
  • Initial off-gassing. Due to some of the chemicals, including volatile organic compounds (VOC), that mattress manufacturers use during the manufacturing process, some memory foam mattresses have an initial off-gassing even though they are brand new. This is due to the polyurethane core, but don’t worry; it’s not toxic, and over a period of time, this smell will go away.
  • Not waterproof. Memory foam mattresses, as well as memory foam mattress toppers, don’t do well around fluids. You need to be very careful to avoid spilling liquids on your mattress. This can even speed up the degradation of your mattress, and its lifespan will be decreased. It makes it hard to clean, as well.

A Few Words Before You Go…

In the end, it all comes to one thing: different memory foam manufacturers use different processes and components to create a wide variety of memory foam. Narrowing it down to one memory foam product will depend on your needs, preferences, and budget. Look out for seals and certification, such as CertiPUR-US, Oeko-Tex, GOTS (Global Organic Textile Standard), or Greenguard Gold, that guarantee you that you’re making the right choice when choosing a high-quality memory foam mattress. 

Bree Taylor - Lead Editor

Lead Editor

Bree is an interior designer with a passion for helping people improve their sleep quality.

She specializes in creating comfortable and functional bedroom spaces that promote a good night’s rest.

When she’s not testing mattresses or helping people get the best rest possible, Bree loves to travel and explore new cultures.

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