Polyurethane (PU) Foam 

What is Polyurethane Foam?

Polyurethane Foam is a soft, low-density foam (although high density PU foam options are available). The foam is a polymer that is composed of organic units joined by urethane links, resulting from the reaction between polyols and diisocyanates.

The primary components of polyurethane foam include:

• Polyols: polyether or polyester-based compounds that determine the foam’s flexibility and resilience.
• Diisocyanates: typically, TDI (Toluene Diisocyanate) or MDI (Methylene Diphenyl Diisocyanate), which react with polyols to form the urethane bonds.

Polyurethane foam is produced through a process called polymerization, where polyols and diisocyanates are mixed with catalysts, surfactants, and blowing agents. The reaction generates heat and gas, creating a foam that can be molded into various shapes and sizes. The foam is then cured to stabilize its structure. Blowing agents are also used to create the foam’s cellular structure by producing gas during the reaction.

The Strengths of Polyurethane Foam:

• Range of Densities: from very low to high, affecting the foam’s hardness and durability.
• Flexibility: the foam varies from soft and cushioning to rigid and structural.
• Resilience: it can return to its original shape after compression.
• Thermal Insulation: it has excellent insulating properties, making it ideal for temperature control applications.
• Chemical Resistance: it’s resistant to many solvents and chemicals, though susceptibility varies with formulation.
• Versatility: can be formulated to be flexible or rigid, catering to a wide range of applications.
• Comfort: excellent cushioning properties for comfort and protection. It’s also nonabrasive.
• Lightweight: high strength-to-weight ratio.
• Durability: long-lasting with good wear resistance.

The Drawbacks of PU Foam

• Cost: can be more expensive than other foams.
• Sensitivity to UV Light: susceptible to degradation when exposed to sunlight.
• Flammability: requires the addition of flame retardants to meet UL 94 safety standards.