What is Foam?

By definition industrial foam is an engineered, polymer-based material designed for high performance industrial applications that require structural support, insulation, padding or even soundproofing. The development of polyurethane chemistries leads to the emergence of industrial foam. Initially polyurethane foam was used in World War II in aircraft. Since then, foam has come a long way with formulations turning foam into a lightweight, flexible material that can be used in a wide variety of applications.

Categories For Foam

Typically, foam is categorized as open cell, like the foam in a mattress, or closed cell, like rubber floor mats. Open cell foams are softer and more breathable. Closed cell foams are stronger and mostly used for insulation and moisture resistance. Most foams start with a base polymer of either polyurethane, polystyrene, polyvinylchloride or polyethylene. Picking the right material to use is dependent on the application.

Polyurethane foam is the most versatile and well-used type of foam. Expanded polyurethane is a lightweight open cell foam that is best for when different shapes are needed. Ester-based polyurethane has a smaller cell structure, which helps make it more rigid and supportive to give shock absorption. Ether-based polyurethane has a large cell structure for more airflow and moisture permeability. Reticulated polyurethane is a porous foam as the cell membrane and impurities are removed, it is good at filtering and absorbing liquids (think sponges).

Polystyrene and polyethylene are types of closed cell foam. Polystyrene is a closed cell foam that is lightweight and rigid. It is good for insulation and shipping products, especially if they have to be temperature controlled. Beaded polyethylene is ideal for shipping and packaging sensitive products as well as good for insulating. Crosslinked polyethylene foam is thicker than beaded polyethylene but is also non-abrasive and resistant to chemicals.

Polyvinyl Chloride (PVC) plastisol foam is another type of close cell foam. In the flooring industry, it serves as a cushioning underlayer in luxury vinyl tiles providing comfort and sound dampening. t is also extensively used in artificial leather and coated fabrics, where it creates a soft, padded surface for upholstery, automotive interiors, handbags, and apparel. In wallcoverings, embossed PVC foam gives decorative wall panels their textured, cushioned appearance. The foam is also found in gaskets and seals for packaging and construction applications.

How Foam Formation Works

Understanding foam formation is critical when manufacturing foam as it affects product performance, process efficiently and the overall formulation success. Foam formation occurs when gas is dispersed into a liquid and stabilized by surfactants. The surfactants help to reduce surface tension and form protective films around bubbles. The films, along with viscosity and elasticity, help to determine how stable the foam is and how long it will last.

Types of Foam Processing

There is several processing methods used to generate foam. Mechanical foaming involves mixing or agitating the system to incorporate air into a liquid. Chemical foaming relies on reactions that release gas into the formulation. Typically blowing agents are used to achieve this. Chemical foaming allows for more control over the cell size, density and expansion but requires more balance with the formulation.

Foam Production

Producing foam happens in a couple of ways. One is extrusion foam production. This process involves melting a plastic resin and mixing it with foaming agents to force the blend through a die. This helps to create a lightweight, cellular structure that is then cooled and shaped. Molding foam production involves injecting or pouring expandable materials like polyurethane into a mold to create detailed foam material. Continuous slab stock foam production contains liquid polyurethane components that are mixed and dispensed onto a conveyor to rise and solidify into endless foam blocks like mattress and furniture.

Blowing Agents

Blowing agents are essential to foam formation. When added to foam the blowing agents create the cellular structure as the agents expand the material making the foam lighter and creating voids that turn into bubbles. There are physical blowing agents and chemical blowing agents. Physical blowing agents are gases or liquids like nitrogen or cyclopentane. These are typically used when low-density foam is needed, for example insulation. When a medium to high density foam is needed or if using injections or extrusion machines to create the foam chemical blowing agents are preferred. Chemical blowing agents are typically isocyanates or azodicarbonamide. Azodicarbonamide is mostly used in PVC Plastisol foam because it is cost effect and helps to release a large amount of gas to create the foam.

Other Key Components

Other key components include surfactants, catalysts, flame retardants and various other additives. Below are some of the additional products used in manufacturing foam:

Polyethylene Glycols – especially for polyurethane foams as they are used as a surfactant and stabilizer.

Tin Catalysts – these help to accelerate the reaction between the polyols and isocyanates.

Castor Oil, Silicone Oil, Soybean Oil – the oils act as polyols in the formulation and help to strengthen the foam structure.

Plasticizers – polyurethane and polyvinyl chloride foam uses plasticizers to help with flexibility and durability. Common plasticizers used are DOA, ESO, DOTP, DINP and DOP.

Flame retardants – are used to help make the foam fire resistant. TCPP, TEP and ATO are the most used.

Example Formulations

General Flexible Polyurethane Foam

A standard flexible slabstock polyurethane foam formulation — suitable as a starting point for cushioning, seating, and padding applications.

• 100 grams Polyol (e.g. polyether triol, MW ~3000)
• 52 grams TDI 80/20 (toluene diisocyanate, ~105 index)
• 3.5 grams Distilled water (blowing agent)
• 0.3 grams Amine catalyst (e.g. TEDA)
• 0.2 grams Tin catalyst (e.g. stannous octoate / T-9)
• 1.5 grams Silicone surfactant (cell stabilizer)
• 5 grams Auxiliary physical blowing agent (optional, e.g. methylene chloride)

PVC Foam Formulation (Plastisol-Based)

A standard flexible slabstock polyurethane foam formulation — suitable as a starting point for cushioning, seating, and padding applications.

• 100 phr PVC Resin – Suspension Grade (Base Polymer)
• 50-70 phr DINP (Plasticizer)
• 3-8 phr Azodicarbonamide (blowing agent)
• 1-3 phr Zinc Oxide (Activator)
• 2-4 phr Barium-Zinc stabilizer (Heat Stabilizer)
• 10-30 phr Calcium Carbonate (Filler)
• 2-5 phr Titanium Dioxide (Whitening/opacity)

Conclusion

Industrial foam has evolved into a highly-engineered material that is essential across many applications. It’s performance depends on the precise combination of base polymers, blowing agents, and additives, as well as careful control of processing conditions. By managing factors like surface tension and gas generation, manufacturers can tailor properties such as strength, flexibility, density, and insulation. This makes foam formulation a deliberate design process rather than simply creating lightweight material. As industries demand higher performance and efficiency, industrial foam will continue to be a key area for innovation and sustainability.