METODO DE PREPARACION DE UNA ESPUMA DE POLIMERO ALQUENILAROMATICO

UN METODO DE PRODUCCION DE UNA PIEZA DE ESPUMA EXTRUIDA DE POLIMERO AROMATICO ALQUENILICO CON UN TAMAÑO CELULAR MEDIO DE 0,05 MM A 3,5 MM, UNA DENSIDAD DE 1,0 LBS/ PIE 3 (16 KG/M3) A 5 LBS/PIE 3 (80 KG/CM3) UN ESPESOR DE SECCION TRANSVERSAL MINIMO DE 0,5 PULGADAS (1,3 CM) Y UN AREA DE SECCION TRANSVERSAL MINIMA DE 8 PULGADAS 2 (52 CM2) COMPRENDE LAS ETAPAS DESCRITAS EN LA INVENCION. A method for producing an alkenyl aromatic polymer extruded foam body having an average cell size of from 0.05 mm to 3.5 mm, a density of from 1.0 lbs/ft (16 kg/m ) to 5.0 lbs/ft (80 kg/cm ), a minimal cross- sectional thickness of 0.5 in (1.3 cm) and a minimal cross-sectional area of 8 in (52 cm ) comprises the steps of: heat plastifying the alkenyl aromatic synthetic resin; introducing the plastified resin into a mixing device; introducing a blowing agent into the mixing device; maintaining a pressure in the mixing device at or above a pressure greater than an equilibrium vapor pressure of the blowing agent in the alkenyl aromatic synthetic resin and blowing agent mixture; passing the mixture through a cooling device; passing the mixture through a die having a given die pressure greater than atmospheric pressure; maintaining a specific defined minimum critical pressure drop between the pressure at the inlet of the mixing device and the inlet of the die. Blowing agents useful in such process are disclosed as well polymer foam bodies made by the process and consistently having improved uniformity of surface quality.