Low-pressure polyurethane fabrication is most often selected for relatively low-volume production applications. Typical low-pressure applications are footwear and CASE (Coatings, Adhesives, Sealants and Elastomers). Low-pressure equipment is also used where very high viscosities or disproportionate viscosities between chemicals do not allow for a good mix using high-pressure impingement mixing equipment. Low-pressure is also selected when four to six -- or more -- chemical streams need to be heated, agitated, degassed, blended and mixed.
The mix head and dispense lines are also flushed with a solvent or one of the chemical streams whenever the flow of mixed material is interrupted, and the pot life or gel time of the formulation being processed approaches its limit.