초록 ▼

An extrusion system utilizes single or tandem extruders and a mixer-cooler to extrude a foamable extrudate through a die in a sealable chamber. The foamable extrudate is shaped and calibrated within the chamber. The die is mounted on the end of a gel tube projecting through a gland seal in a fixed b

An extrusion system utilizes single or tandem extruders and a mixer-cooler to extrude a foamable extrudate through a die in a sealable chamber. The foamable extrudate is shaped and calibrated within the chamber. The die is mounted on the end of a gel tube projecting through a gland seal in a fixed bulkhead forming the upstream end of the chamber. The gel tube and mixer-cooler are mounted on a movable carriage, movement of which may be used to adjust the die with respect to shaping and calibrating equipment inside the chamber. The mixer-cooler achieves a selected narrow range of uniform viscosity of the melt at the die depending on the size of the product and density. The chamber is preferably a vacuum chamber producing low density foams. The product exits the chamber to atmosphere on a continuous basis through a submerged orifice in a water baffle immersion seal. The mixer-cooler enables a large size low density product to be produced with uniform cellular structure without cell collapse or density gradients, as the product is subjected to the pressure and temperature transformations passing from the chamber to atmosphere through the water. The seal includes the submerged orifice with a free wheeling guiding system upstream of the orifice. Immediately ahead of the guiding system, the parameters of the foam extrudate are sensed to control the configuration of the orifice on a continuous basis. Before the extrudate passes into the water baffle seal it moves over a floating dancer roll, the position of which controls a haul-off such as a vacuum belt at the tail end of the system. This avoids pushing on the extrudate.

대표청구항 ▼

[ What is claimed is:] [1.] An extrusion line comprising an extruder feeding a polymer melt to a mixer-cooler for cooling the melt wherein the mix-cooler includes a conical head plenum at each axial end, with a coolant vessel therebetween, and a plurality of mixing tubes extending between such plenu

[ What is claimed is:] [1.] An extrusion line comprising an extruder feeding a polymer melt to a mixer-cooler for cooling the melt wherein the mix-cooler includes a conical head plenum at each axial end, with a coolant vessel therebetween, and a plurality of mixing tubes extending between such plenums through the coolant vessel; a sealable chamber, a fixed bulkhead forming the upstream end of said chamber, a gel tube extending from the mixer-cooler through the bulkhead, a die on the interior of the bulkhead supported by the gel tube, an extrudate shaping mechanism supported on the interior of the bulkhead surrounding the die, and means to adjust the position of the die with respect to the shaping mechanism by axially moving the extruder, mixer-cooler and gel tube as a unit with respect to the bulkhead and shaping mechanism.