In-mold coating method and apparatus

A method of forming a coating layer on a molded product formed in a split-type mold assembly, which assembly comprises first and second dies supported for movement relative to each other, and an injector means for injecting fluidized coating material, said injector means including a valving rod slidably extending through a supply passage means, defined in the first die, for movement between projected and retracted positions, said injector means being positioned on one side of the first die remote from the second die, said valving rod having first and second ends opposite each other, the first end of said valving rod being coupled with a drive source and the second end of said valving rod confronting the second die through the passage means, said second end of the valving rod being, when the valving rod is moved inwardly of the first die to the retracted position, clear from the passage means to permit the latter to be opened, said valving rod adapted to close the passage means after the valving rod has been moved a predetermined distance from the retracted position toward the projected position, which method comprises the steps of:

• placing a sheet of fiber reinforced thermosetting resin, having a perforation defined therein, on the first die with the second end of the valving rod aligned with and extending through the perforation while the valving rod is held in the projected position;
• moving one of the first and second dies close to the other of the first and second dies to close the mold assembly to heatpress the sheet to complete the molded product having first and second surfaces opposite each other;
• separating the second die from the second surface of the molded product to provide a coating space between the second die and the second surface of the molded product;
• moving the valving rod to the retracted position with the second end of the valving rod clear of the passage means to permit the passage means to communicate with the coating space through the perforation in the molded product, while leaving the perforation in the molded product;
• injecting the coating material into the coating space through the passage means and then through the perforation in the molded product;
• moving the valving rod in the retracted position toward the projected position to close the passage means;
• and
• moving one of the first and second dies close to the other of the first and second dies to form the coating layer on the second surface of the molded product.