Patent ID: 6042764
Filing Date: 2000-03-28
Classification: B29C,Y10S,Y10T

Abstract:
A method of producing a three-dimensional shaped plastic foam part, comprising the steps of(a) mixing plastic foam granules having at least one property selected from the group consisting of a predetermined range of sizes and different hardness in a predetermined mixing ratio to obtain a mixture of the plastic foam granules, mixing the mixture of the plastic foam granules with a liquid primary material until the granules are coated with the liquid primary material and a mixture of coated plastic foam granules is obtained,(b) storing the mixture of the coated plastic foam granules in an intermediate storage tank,(c) conveying a preset quantity of the stored coated plastic foam granules from the intermediate storage tank to a mold cavity of a mold closed on all sides,(1) the stored coated plastic foam granules having been weighed to provide a quantity thereof which is between 3% and 15% above the quantity required to fill the mold cavity, and(2) the weight of the stored coated plastic foam granules having been so controlled that it corresponds exactly to that of the quantity to fill the mold,(d) reducing the volume of the mold cavity at least in partial regions thereof after it has been filled with the mixture of coated plastic foam granules,(e) triggering a reaction of the liquid primary material by applying pressure and heat until a continuous cellular structure of plastic foam has been formed and the plastic foam granules have been interconnected by the cellular structure of plastic foam after the volume of the mold cavity has been reduced at least in partial regions thereof,(f) venting gaseous reaction media from the mold cavity through openings in the sides of the mold, and(g) removing the three-dimensional shaped part from the mold cavity.