PUR foam production

Breathing dryer on IBC containers with isocyanate and other chemicals

GIEBEL Adsorbers® increase the quality of PUR foam products and reduce production waste. By effectively drying the air, isocyanates, polyols and other chemicals are protected from contamination with water during storage and processing.

Isocyanates and foam production

When polyols are mixed with isocyanates and blowing agents, the polyol reacts with the isocyanate to form PUR (polyurethane foam).
Additives as well as the blowing agent are added to the polyol, so that two components are usually used. Depending on the properties can be adjusted depending on the choice of starting materials. Thus, soft to elastic foams are obtained when long-chain polyols are used, or strongly cross-linked hard foams are obtained when short-chain polyols are used.

Necessity of adsorbers

At a leading international manufacturer of quality products made of flexible polyurethane foam, an …

  • Isocyanate
  • Polyol
  • Amines
  • PU metal catalysts Cosmos 29
  • Flame retardant Celltech 60
  • Diethanolamine
  • Silicone 8266 from Evonik

… found that contact with water from the air leads to undesirable side reactions. This results in the formation of CO2 in the molding compound, which remains trapped in the cured molding material. This property necessitates consistent compliance with the processing conditions, if reproducible service properties are to be ensured in the product. This includes, in particular, the control of air humidity.

Adsorber on IBC with Icocyanate

Trapped CO2 in the final PUR product

During the storage and processing of isocyanates and polyols in an industrial building, the average ambient conditions are 20°C and 70%rh. Thus, the water content is approx. 12g/m³ air. When a complete IBC is emptied in this way, 12ml of water is sucked out of the air and contaminates the substance.

Function breathing dryer on IBC

To protect the IBC contents from moisture, respiration dryers are used, which are screwed directly onto the cover. All the air drawn in is completely dried.

During the extraction of the isocyanate, polyol, silicone, PU metal catalyst or other substances, the air drawn in is dehumidified to an initial 2%rh (average 10%rh). Thus, the air drawn into the IBC contains only contains 1.7g of water per m³ of air (1x IBC unit). This almost completely eliminates the influence of humidity on the isocyanate.

Added Value for Vita Cellular Foams: High Quality for Flexible Foams

The use of GIEBEL adsorbers ensured the production of high-quality PUR flexible foam at a company of the Vita Cellular Foams group. The production waste was reduced and the end product quality was increased. This simple and effective measure to protect the isocyanate could be easily integrated into the existing production without any conversion measures. The result was visible from day one and increased customer satisfaction.