How is Foam Rubber Made?
Foam rubber uses a chemical additive called `blowing agent` to generate a gas that creates thousands of bubbles in the liquid mixture. The liquid mixture consists of liquid polymers (Polyols, Polyisocyanates), water or colorants. Liquid polymers generate heat when mixed with water, and if we combine different liquid polymers, we can create flexible or rigid foam rubber depending upon the composition.
The blowing agents should be used in an accurate amount as they play a major role in making the foam flexible or rigid. Usually, manufacturers use carbon dioxide gas to make the foam flexible, while hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are used to form a more rigid foam rubber.
Uses of Foam Rubber:
Polyurethane foams are useful in shock absorption and vibration control. These forms are rigid and do not spread when compressed. Some of the major applications include shock absorbers for industrial machinery, hood gaskets in mobile devices, and vibration isolators for different appliances.
Polystyrene foams are strong, light, and moisture resistant. Their high stiffness-to-weight ratio makes them a preferred choice for home and appliance insulation, lightweight product packaging, food packaging, surfboards, automobile parts, etc.
Reticulated foams (extremely open foams, like a net) are useful for filtration. Flexible foam rubber is used in soles and heels, automobile seats, mattresses and pillows. Rigid foam rubbers have their application in refrigerators and freezers.
Sponge rubbers have been used in automotive, marine, public transport, and aviation sectors. Open-cell sponge rubber has its application in gaskets, seals, and protective padding, as it can resist sunlight and UV rays. Closed-cell sponge rubber is useful for cushioning, soundproofing, weather-stripping, thermal insulation, etc.