Abstract: Apparatus and method are described for improved production of foamed bunstock in continuous length. A generally U-shaped moving mold is utilized within which a thermosetting foam mix is deposited and the bunstock is then formed as a continuous block. This moving mold is configured along a critical portion of its length to conform as closely as practical to the inverted mirror image of the profile defined by the characteristic curve of percent of foam rise as a function of time for any selected foam mix composition. A weir arrangement is employed to control the travel of foam mix while this is still highly liquid. The objective is to maintain a condition of hydrostatic balance throughout the body of developing foam from the point of mix lay down to the point of foam gellation.

Abstract: Methods and apparatus are disclosed for continuous mixing of formulations for urethane products. A hydroxyl mixture and isocyanate, the major foam components, are supplied to a mixer. In the mixer, the components are mixed by transverse shearing and agitation means. The degree of agitation is varied along the length of the mixer, which runs at a constant speed, by varying the shearing pin configuration. The flow path through the mixer is arranged to control pressure on the fluid as well as minimize the tendency of internal foam build-up to occur.