Polyurethane is a polymeric material with many applications that is characterized by being formed by more or less intertwined polymer chains, creating from very soft products to completely rigid ones.

These polymers are formed from exothermic polymerization reactions of the two main components: Isocyanate and Polyol. When the reaction takes place inside a mold, we speak of molded polyurethane.

The high adhesive power of polyurethane is a great advantage in many of its applications, but also a disadvantage when it comes to unmolding. Mold release agents are vital products in many sectors of the industry. The product forms a barrier between the mold and the surface of the molded part.

The action of the release agent is so important that it is directly responsible for the appearance and surface properties of the part once it is unmolded. It also affects the production process, repairs, dirt left in the mold and even the work environment.

Concentrol takes care to produce the appropriate release agent for each customer’s needs, as there is no universal release agent and this must be adapted to a large number of variables such as temperature, material and geometry of the mold, cycle time or the surface finish of the pieces.

One of the product families available at Concentrol is the hot-curing flexible polyurethane foam release agent.


Flexible hot curing polyurethane foam

This production process produces foam for seats, backrests, and headrests for cars and other means of transport such as airplanes, buses or trains. You can also make pieces for furniture and the bed sector.

This type of flexible foam production is obsolete, as it requires much higher energy consumption than cold curing. Molds, usually made of steel or aluminum, are heated to 160-180 °C.

The molds have, in most cases, an injection point through which the mixed components are introduced at high or low pressure. At this point in the process, the temperature is about 30 to 40 °C. Once closed, the molds are placed in an oven at 180 °C through a rotating carousel. They spend about 20 minutes in there and 10 more in the rest of the route.

When the mold leaves the oven it opens, it is close to 120 °C and follows the path until, thanks to a mechanical air distribution system and thanks to the application of the release agent, the mold is cooled until the area of placement and injection is at 30 °C.

The release agents used allow a correct curing in both steel and aluminum metal molds. When this is applied, diluted in water, the mold is above 100 °C, the water of the dilution intervenes by cooling the molds.

In general, the finished parts made with this system have a closed leather finish and small pores. The Concentrol product also allows you to include a formulation in the release agent that gives it anti-noise properties, such as that which occurs when we move in a seat, the foam of which is in contact with a metal structure.

The concentrate is applied with air-less systems, as the process temperature allows it; it is not necessary to put air in its application because the mold is at a temperature close to water boiling point.