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What is Polyurethane Foam?

what is polyurethane foam

Polyurethane foam is one of the most common types of foam used throughout our day-to-day lives. It is the same type of foam you may find in many sofa cushions and mattresses.

Unlike polyethylene foam which generally has closed cells, you’ll generally find polyurethane foam has open cells. This is what helps make it ideal for comfort, amongst many other things.

What are Polyurethanes?

Polyurethanes are one of the most prominent members of the polymer or plastic family; they are used to create many items we use daily. Such items include foam seating, adhesives, hoses, hard-plastic parts, synthetic fibers and much more.

Polyurethane foam is made by introducing various blowing agents during the process of making polyurethane. These blowing agents cause a chemical reaction inside the material, causing pockets of gas to form within, giving the foam an open cell structure. This material is often used in a variety of soft furnishings, among many other things.

These are just a few examples of areas where you’re likely to find polyurethane foam being used:

And that’s just a few examples. Many of us use polyurethane foam every single day of our lives. There’s a good chance that you often sit on it during the day and sleep on it during the night (depending on your sleep schedule of course).

Open Cell Polyurethane Foam Vs Closed Cell

As you’ll see from the application examples above, polyurethane foam is commonly used as a means to provide comfort.

The majority of us find that it’s much better to sit on something plush than to relax on something solid. If you were given the option between sitting on a large rock or sitting on a foam cushion, which would you choose?

Most of us don’t like the idea of sitting or sleeping on solid surfaces. Even if you prefer a firm feeling foam, it will still have some give. When you sit or lay on a solid surface, your body is put under more pressure has no choice but to conform. This restricts blood supply causing aches, discomfort and sometimes a numb behind.

The reason polyurethane foam conforms to applied pressure is that it has open cells. When the foam is fully formed, the cells are filled with air. When we sit on the foam, we force the air out and restrict its ability to return to the open cells. This is what causes the foam to compress and change shape. When we stand up, the open cells are no longer restricted, air returns and so does the shape.

If a foam is classified as closed-cell it means the majority of its cells retain air (some closed cell foams such as Plastazote are filled with nitrogen, an unreactive gas that is slightly lighter than air). If the gas contained within the cells does not escape, the foam will offer much more resistance. This is why closed-cell foams are popularly used for things like packaging and various pieces of protective equipment.

How is Polyurethane Foam Made?

Put simply, polyurethane foam is made by reacting polyols and diisocyanates together. During the manufacturing process, the foam can be manipulated in various ways to create different types of polyurethane foam. This helps to create materials suitable for a wide array of purposes. You can find an example of this on our memory foam page where we discuss how foam can be manipulated during the manufacturing process.

Foams can be manufactured to feel very firm, very soft or somewhere in between and each type offers its own benefits.

For example, each of us have different preferences when it comes to comfort, so being able to manufacture foam in various different ways is essential. Many people wouldn’t want to sleep on a very hard piece of foam and similarly wouldn’t want to sit on a very soft piece, as it would offer no support.

About Foam Density

Polyurethane foam can have a low density or a high density. High density foams are considered to be of better quality and have an improved lifespan. At GB Foam Direct, our polyurethane foams are high-quality and are classified as high density.

It’s a common misconception that density directly correlates with how firm a foam feels. People often believe that if they need a firm foam they need something with a high density and a low density for a soft foam. This isn’t true. High-density foams can feel soft, medium or hard. Foam density is calculated by the weight of the foam per cubic foot.

For example, if we wanted to measure the density of a certain peice of foam we would take a cubic foot of it (12″, 12″, 12″) and perform the following calculation Weight ÷ Width x Height x Length. This is how we would find the density of a piece of foam.

Polyurethane Foam Cut to Size

We stock a wide range of foam types here including many polyurethane foam grades. By utilising advanced cutting equipment and with the help of our talented foam cutters, we can cut foam to practically any size and shape you need.

Every day, customers turn to us to provide them with the bespoke foam products they need; whether that be for replacement sofa cushions, custom packaging, a unique mattress or something else entirely.

If you require a custom foam product, be sure to check out our foam cut to size page. Here, you’ll be able to choose from our wide collection of common foam shapes. We even offer a custom option if you can’t see the shape you’re after.

If you’re unsure about anything or can’t find what you’re looking for our team of foam experts are always happy to assist.

What Other Types of Foam Exist?

There are many different types of foam and not all are in solid form. Shaving foam, for instance, would be an example of foam that is not solid. Substances that are formed by trapping pockets of gas (whether it be in a liquid or a solid state) are known as foams.

Foam can have an open or closed cell structure. Closed cell foam (such as polyethylene foam) consists of gas pockets that are surrounded by solid material, meanwhile, the gas pockets in open cell foams are interconnected, allowing air to pass in and out of them freely. Other foam types include metal foam, polystyrene, XPS and phenolic foam.

Buy Polyurethane Foam at GB Foam Direct

Whether you need foam cut to size to replace your sofa cushions or require sheets for an upholstery project, we can help. We’ve been supplying high-quality foam products worldwide for more than 45 years.

We have a wide range of foam types to choose from including high-density upholstery foam, packaging foam, acoustic foam, reticulated foam and much more.

Need some help? Feel free to contact us. A member of our team will be happy to assist you with any questions you may have about our services.

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