Q. What is Polyurethane (PU) Injection Molding?
A. Polyurethane (or PU) Injection Molding refers to the mixing of materials (poly, isocyanates and a raising agent). Materials can be produced with a wide variety of characteristics ranging from flexible to firm rigidity with composition from porous to dense. Materials that are as different as inte-gral skin and rigid foam are created from the same process.
Q. What is integral skin?
A. Urethane foams that are formed with integral skins range from soft and flexible types to impact-absorbing grades. Color can be added, but since the material yellow on aging, black is most practical for the surface color.
If other colors are required, coatings are recommended. The tough, high-density, integral skin is formed against the mold surface and the low-density core is produced by a blowing agent - usually a fluorocarbon.
Q. What is rigid foam?
A. Rigid foams are polymers typically used for cushions. The cells of rigid foam are about the same size and uniformity as those of flexible foam, but rigid foams usually consist of 90% closed cells. For this reason, water absorption is low.