How is the rolled lip on balloons made?
Each balloon mold is the shape and size of the un-inflated balloon. The molds are arranged into rows and dipped into liquid latex in assembly line fashion. The latex at the top (thin) end of the mold becomes the “lip” when it is rolled down (toward the wide end) by a device which looks like a small motorized brush. As the rows of molds progress down the line, they pass between rotating, cone shaped brushes that are positioned horizontally, one on each side of each row of molds, pointing at the approaching molds. The brushes turn in opposite directions and are positioned so they touch the molds on each side. The point of the brushes start rolling the lip, and the lips continues to form as the row of molds moves along the line from the point to the larger end of the brushes. This occurs while the latex is still uncured, just before it is vulcanized.
