What Is Urethane Insulation?
Urethane insulation is a heat-insulating material made primarily of polyurethane resin.
Urethane insulation is made by forming (foaming) polyurethane resin, which has many independent bubbles inside. Each of these bubbles is filled with a gas that conducts little heat and thus has high heat insulation properties.
Uses of Urethane Insulation
Urethane insulation is used in a wide variety of buildings. In addition to its high thermal insulation properties, urethane insulation is also suitable as a soundproofing material because of its soundproofing properties.
For this reason, it is also used in roofs, walls, and ceilings of agricultural and stockbreeding facilities, as well as in constant-temperature rooms for tobacco drying, which require high temperatures and long drying times. It is also used in ships, plants, and furniture.
Principle of Urethane Insulation
Polyurethane resin, the raw material for urethane insulation, contains both polyisocyanate and polyol that bond together to form a polymer. In urethane insulation, a foaming agent is added, and the heat from the reaction between the isocyanate and polyol vaporizes the foaming agent, creating many small independent bubbles.
Each of these bubbles is then filled with gas derived from the blowing agent, thus achieving a high heat-insulating effect. In addition, since there are many gas-filled bubbles, it is highly effective in absorbing sound, and a soundproofing effect can also be obtained.
Other Information on Urethane Insulation
1. Advantages of Urethane Insulation
The advantage of urethane insulation is that it is a self-adhesive, foam-like material that can penetrate complex shapes and structures, such as uneven surfaces in the construction area, without gaps, and form an insulation layer. Another advantage is that there is little deterioration, and the difference between initial insulation performance and insulation performance after aging is small, so it retains its insulation effect even when it is old.
Urethane insulation is also highly waterproof. This is because each air bubble inside urethane insulation has an independent structure, making it difficult for moisture to penetrate inside the urethane insulation. For this reason, urethane insulation does not lose its insulating effect, even when wet.
2. Disadvantages of Urethane Insulation
The biggest disadvantage of urethane insulation is its high price. There are two types of insulation materials: foam insulation materials such as urethane insulation and fiber insulation materials such as glass wool. The price of urethane insulation is about 1,900 to 2,700 yen per square meter for a sprayed type, and about 3,000 to 4,000 yen per square meter for a ceiling, more than twice the price of glass wool.
Another disadvantage of urethane insulation is that it is difficult to peel off once it has been installed because of its high self-adhesiveness and the fact that it is installed without gaps. In addition, restoration after peeling is also costly.
3. Relationship Between Urethane Insulation and Fire
Because urethane insulation has low fire resistance, in recent years it has become a requirement to install insulation that meets fire resistance standards. Although there is an aspect that “urethane foam insulation is flammable,” it is very rare for urethane foam insulation to be the cause of a fire.
In actual cases of fires, most fires from urethane insulation occur at the construction site. During construction, remodeling, and demolition, there have been instances where sparks or welding burners have ignited due to the use of urethane insulation while various workers were entering and exiting the site.
To prevent fires involving urethane insulation, it is necessary to take firm precautions on site as well as by the occupants. It is important to have a correct knowledge of the material, such as “it is a heat insulator, not a heat-resistant material,” and “it burns even if it is flame retardant,” and to handle it safely.