| abstract |
Colored expanded polyurethane foam articles are made by simultaneous discharging of measured amounts of isocyanate A, a suitable resin B, and a color pigmented liquid C into a mixing chamber in which is situated a rapidly rotating mixer. The mixed charge resulting flows by gravity into the lower section of an article mold. A mating upper section has a bleed hole through the top and is clamped onto the lower section until the resulting foam has risen and set. The mold sections are unclamped and the article ejected from the lower mold section by striking on an ejector pin slidably mounted in the bottom of the lower mold. Apparatus for mixing and delivering this charge of urethane foam to the mold typically includes a mixing head to simultaneously deliver the two liquids A and B to the mixing chamber to be mixed and discharged into a mold. By simultaneously adding the color pigmented liquid C to this chamber through a supply conduit and the mixing head, a uniformly colored charge can be obtained. To change colors, only the supply conduit for liquid C is detached, the head flushed out and a second supply conduit C is attached to the head. |