A manufacturing method for a seamless manmade leather ball comprising an inflatable ball bladder having a binding yarn or cloth thereon peripherally wrapped to form a reinforcement layer, protrudingly made with an air charging inlet, wherein the manufacturing method further comprises:
- injecting, extruding, or hot compressing a soft bioplastic resin or manmade leather to form an upper and lower hemisphere shaped thin cover each having a middle seam edge;
- enclosing the inflatable ball bladder into the upper and lower hemisphere shaped thin covers to form a sphere;
- placing said sphere into a first curing mold, where said first curing mold comprises two hemisphere shaped molds capable of opening and closing in a vertical direction, said first curing mold further comprising a temperature heating control device operative to adjust the temperature applied by said first curing mold;
- pressing to combine said first curing mold under a medium temperature suitable to soften any resin content of said hemisphere shaped thin covers to paste the middle seam edges between the upper and lower hemisphere shaped thin covers to form an integrated unit;
- continuing to press first curing mold until the inside surfaces of said hemisphere shaped thin covers are pasted and fused onto the periphery of said ball bladder to form an initial blank;
- subsequently removing and placing said initial blank in a second curing mold, said second curing mold further comprising a temperature heating control device operative to adjust the temperature applied by said second curing mold;
- raising the temperature of said second curing mold to a high temperature suitable to induce a curing condition for any resin content of said initial blank and a complete pasting of said thin covers at the external periphery thereof to form a waterproof layer upon said initial blank;
- subsequently placing said blank with waterproof layer, into a forming mold capable of opening and closing in a vertical direction, said forming mold adapted to apply a low temperature suitable to impress designs upon the blank with waterproof layer, said designs further comprising any combination of:
- preformed shaping blocks or convex distributed seams;
- pressing the forming mold upon said blank with waterproof layer to form a seamless base body impressed with designs of reverse shape or reverse concavity with respect to the designs adapted by said forming mold;
- subsequently applying a cortex treatment to the surface of said seamless base body, said cortex treatment comprising any combination of:
- soaking, spray coating, smearing, or leather film wrapping the surface of said seamless base body;
- subsequent to the application of the first and second curing molds, impressing serpentine or convex-concave shaped lines arranged to allow connecting seams of the blank with waterproof layer to be hidden among the lines by said forming mold;
- and
- smoothing out the connecting seams of the blank with waterproof layer after treatment by said forming mold.