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In this post, we answer the questions of whether Polyurethane foams are safe for babies and include other guides on how Polyurethane is made, whether it is waterproof, flammable, a good insulator, history, and more.

Let’s start with the history and invention of Polyurethane;

What Is Polyurethane Foam/ History and Invention

Polyurethanes are polymers made by reacting diisocyanates (methylene diphenyl diisocyanate [MDI] and/or toluene diisocyanate [TDI]) with a range of polyols. They belong to the same family as plastics. Polyurethane can have a solid or open cellular structure. Polyurethanes in an open structure are called polyurethane foam. The foam structure can be rigid or flexible.

The history of polyurethane invention dates back to the 1930s in Germany by Dr. Otto Bayer. This was around the same time baby monitors were invented. During World War II, polyurethane was being used as aircraft coating but in 1954, after the war ended, commercial production of polyurethane foam began.

We encounter polyurethanes daily in our lives, whether we know what they are or not because they are widely used across various industries not only in foam but also in the manufacture of paint, adhesive, spandex, and lycra clothing material.

Polyurethane foam makes the mattress we sleep on, furniture padding, and insulating panels, dishwashing sponges, medical dressing, soundproofing, and more.

How polyurethane foam is made

Polyurethane foam is made from a reaction of diisocyanates (derived from crude oil) and polyols (complex alcohol). The two ingredients are mixed to form hot liquid polyurethane, which is then run through a pipe into a nozzle head. Beneath the nozzle head is a series of rollers upon which waxed paper passes by.

The nozzle jets a fine spray of the hot polyurethane upon the waxed paper, mixing with blasts of carbon dioxide from another nozzle. This causes the polyurethane to expand as it passes along on the conveyor belt, forming a foam strip.

The foam is then trimmed and compressed for it to reach a viable/desired shape. This foam contains numerous tiny gas bubbles trapped in the polyurethane which, if the gas is not released, the resulting material would be rock-hard. To prevent this from happening, the foam is passed through a series of heat lamps to dry, and as it dries, the gas bubbles expand until they burst to leave a spongy, porous material which is the polyurethane foam.

Why is polyurethane foam a good insulator?

Polyurethane foams are used for insulation of wall panels, roof tilting, joining wooden elements, and to seal and sound-insulated partition walls.

The reasons why polyurethane foam is good for insulation include:

  1. Provides excellent thermal insulation

Although it is expensive to invest in at first, it saves you 30% -50 % of heat costs with full investment returns after about 8 years of use, making it highly cost-effective.

  1. Durable

It does not change its mechanical and insulation properties despite the passage of time; neither is it biodegradable.

  1. Impregnating

It protects timber against mold and metal against corrosion

  1. Environmentally safe

Polyurethane foam does not cause dust, crumble, oxidizes but retains its properties throughout. It is also resistant to mold and fungus.

  1. Lightweight

Polyurethane is lighter than mineral wool; hence it doesn’t weigh down building structures much.

  1. Fast installation

Studies have shown that people installing polyurethane foam are able to cover more than double the area, within the same duration as if they were installing mineral wool.

  1. Adhesion

Physical properties of foam enable it to adhere to surfaces while filling any gaps perfectly. It adheres to wood, OSB boards, bricks, concrete, and vapor-permeable foil.

  1. Vapor permeable

Although it seals tight, it allows vapor to permeate.

  1. Provides better air quality inside the building

It forms a barrier against dust and allergens hence promoting cleaner and fresher air quality inside foam-insulated houses.

  1. Easy to use

Unlike mineral wool, polyurethane foam adheres to any surface without needing additional installation tools like nails or strings.

Are polyurethane foam pillows safe?

The chemicals materials used in the manufacture of polyurethane are known to be toxic and According to the United States Environmental Protection Agency (USEPA), exposure to isocyanates can lead to adverse health effects such as skin inflammation, eye, and lung irritation, asthma, and sensitivities.

In 2004, a US Law took effect, requiring all mattresses to be flame resistant. Because polyurethane foam is extremely flammable, manufacturers resulted in treating the foam with flame retardant chemicals and adding to the toxicity. Flame retardant chemicals are volatile and persist in the environment causing harm to people and animals according to USEPA.

Catalysts such as benzene or toluene used during manufacture can cause sensitivity, irritation, and blurry vision.

Generally, these volatile organic compounds are released from polyurethane foams during manufacture in high amounts and at home in minimal quantities, especially when the products are new. Think of the odor that hits you when you first unwrap a new mattress? But studies show that the release of these VOCs decreases over time.

Polyurethane mattresses and pillows are chemical-ridden, but they are regulated and accredited by CertiPUR-US to make sure they meet standards for content, emissions, and durability.

CertiPUR-US certified polyurethane foam mattresses and pillows are approved as safe, but natural eco-friendly alternatives are even much safer.

Are polyurethane foam mattresses safe?

While Polyurethane mattresses and pillows are full of chemicals, they are heavily regulated to ensure safety and are accredited by CertiPUR-US to make sure they meet standards for content, emissions, and durability. CertiPUR-US certified polyurethane foam mattresses and pillows are approved as safe, but natural eco-friendly alternatives are even much safer.

Is polyurethane foam flammable?

The chemical composition of polyurethane foam makes it flammable that is why some manufactures treat their polyurethane foam products with flame retardant chemicals.

Is polyurethane foam waterproof?

Polyurethane only repels water to a certain extent, but it never entirely repels it, so it is not 100% waterproof.

Can polyurethane foam be washed?

Polyurethane can be washed by submerging it in water and gently pressing it down, or running water over it until it is clean. You can also use detergents because they do not affect it. However, an aggressive washing method like machine wash would destroy the physical cell structure causing the foam to rip. Also, it is advisable to air dry it as opposed to using the drier because the heat from the drier could damage it as well.

Can polyurethane foam be recycled?

Polyurethane foam is made from polyurethane, a thermoset resin, made by mixing two parts to form a chemical chain that is irreversible. Hence polyurethane foam cannot be recycled.

Does polyurethane foam contain latex?

Polyurethane foam does not contain latex, but it can be made to have similar properties as latex. Latex is made from sap trees, while polyurethane is a polymer made from a reaction of diisocyanates with polyols.

How to make polyurethane foam at home

Supplies

  • Mold
  • Mold-release spray
  • Large, disposable container
  • Stirring stick
  • Two-part urethane liquids
  • Safety gear: goggles and a respiratory mask

Put on the goggles to protect your eyes and mask to keep you from inhaling toxic chemicals.

Procedure 

Solid Foam 

Step 1

Choose a mold to the foam you wish to make. Solid foam takes the shape of the object.

Step 2

Spray the mold-release spray all over the mold and allow the spray to dry for 24 hours before adding the foam liquid.

Step 3

Pour out the two urethane liquid in equal measure in a large disposable container and stir the mixture using the stirring stick.

Step 4

Pour the liquid into the mold within 15 minutes of mixing the liquid. The foam will start to set within 15 minutes.

Step 5

Keep the mold in a room with a temperature of about 70℉ to allow the foam to cure. Colder temperatures will prevent the foam from curing properly.

Step 6

Remove the foam from the mold after 24 hours.

Flexible foam

Step 1

Choose a mold to the foam you wish to make. Solid foam takes the shape of the object.

Step 2

Spray the mold-release spray all over the mold and allow the spray to dry for 24 hours before adding the foam liquid.

Step 3

Pour out the two parts of urethane foam mixture in a ratio of 28 parts hardener and 72 parts of urethane foam liquid. Mix the two parts together using the stirring rod until they start to expand.

Step 4

Pour the foam into the mold and leave some room for expansion. In 15 minutes the foam should be fully expanded.

Step 5

Keep the mold under room temperature of at least 70℉ and allow the foam to cure for 24 hrs.

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