What Is Polyurethane and Where Is It Used?

Polyurethane is a polymer formed when organic components create urethane bonds. Many types exist. Most are thermosetting, retaining their solid form without melting even at high temperatures. Thermoplastic polyurethanes, which melt when heated, also exist.

Many polyurethane types have an open-cell structure, giving them a foam-like form whether solid or liquid. Much of the polyurethane we encounter daily is therefore foam, and the term polyurethane foam may be more familiar than polyurethane alone.

There are many kinds of polyurethane foam. The binding material can vary, creating a new compound with each different binder. Most results are almost identical, but patents can lead manufacturers to use different substances, giving each formulation a new name.

Where Is Polyurethane Used?

Polyurethane foams, or PU foams, are among the most versatile materials in construction. They are particularly chosen for insulation, gap filling, thermal and acoustic insulation, bonding and passive fire protection.

Construction today is unimaginable without insulation, making insulating materials a priority. PU foams come in different forms, including cans with one- or two-component products and versions for manual or specialist gun application. Depending on type, they can expand up to 30 times their original volume. Curing occurs through interaction with moisture in the air.

Gap Filling

Polyurethane foams are ideal for gaps and cracks between walls and buildings and for air gaps left around doors and windows during installation. Standard or premium foams suit these tasks. Gun applicators are easy even for non-professionals and particularly recommended for small gaps.

Thermal Insulation and Airtightness

Insulation, especially thermal insulation, retains heat in buildings, protects the environment and saves money. It should never be omitted. Door and window installation inevitably leaves some gaps, which polyurethane foam can fill. Even narrow openings can increase fuel consumption substantially. PU foam prevents heat transfer quickly and at low cost. It expands after application and adheres excellently for an airtight seal. Once cured, it does not deteriorate or break apart, preserving insulation for years and completely blocking airflow.

Specialist polyurethane foams for insulation and airtightness offer high insulation values and low air permeability. They keep interiors warm in winter and cooler in summer, help reduce fuel bills and are very easy to apply.

Sound Insulation

Polyurethane foam between construction layers is an excellent sound-insulation choice. Acoustic PU foams successfully block moderate sound levels such as conversation and music, preventing transmission both indoors and outwards. PU foam is an essential building material for musicians’ studios and homes. All polyurethane foam types are suitable for sound insulation.

Bonding

PU foams can also be used confidently for bonding. Both one- and two-component versions are available. Application needs no specialist space and is quick because the foams cure rapidly. They are environmentally considerate and solvent-free. Use is simple and requires no subsequent cleaning, particularly with a can or gun applicator. They are also more affordable than comparable adhesives while remaining among the strongest.

Fire Protection

Ordinary PU foam cannot be described as non-flammable or as stopping fire spread. Not melting again under heat does not make it non-combustible. Specialist fire-protection PU foams are available. Their fire classification, tested joint and application instructions must govern use. Standard mounting foam must not replace a fire or smoke barrier.

Polyurethane foams play a larger role in life than we might expect, appearing in almost everything from car seats to the memory foam in mattresses and pillows.

In construction, mounting foam fills gaps and cracks around doors and windows. Its durability and resistance to air and water make it useful for joining cold-air pipe sections. Waterproofing and weather resistance are also valuable for placing and bonding roof tiles. It performs similarly well in industrial roof insulation.

Water resistance makes it popular for exterior work in boat and yacht construction and repairs. Air- and moisture-blocking properties also make polyurethane a choice for insulating dry-food stores.

Even the washing-up sponge in your hand may be PU foam. This industrially transformative material is easy to use and affordable. It does not harm the environment; its insulation benefits make it one of the best building materials for the environment over the long term.