| 摘要 |
There are disclosed an apparatus and a method for continuously embossing synthetic plastic sheet material with precisely formed embossments in patterns repeating along the length thereof. The apparatus includes a movable polished belt upon which the sheet material is carried, and a series of molds are placed on the sheet material. As the sheet material and molds are advanced in steps through the apparatus, presses clamp the molds and belt against opposite surfaces of the sheet material and raise the temperature of the assembly to embossing temperature for the resin to cause the resin to flow into the mold cavities, and volatiles at the interface are dissolved in the resin. After the embossing step, the clamping pressure is released and this permits limited shrinkage of the mold and sheet material. At subsequent stations, controlled temperature reduction is effected, and limited shrinkage is permitted after the clamping pressure is released at each station and as the material and molds move to the next station. Mold distortion is thus avoided and the embossments remain precisely formed. |
