Polyurethane material for two and three piece golf balls and method

A golf ball comprising:

• a core comprising a center and thread layer wherein said core has a diameter of about between 1.48″ and 1.62″;
• and,
• a cover comprising:
• (a) a polyurethane prepolymer comprising:
• (1) a diisocyanate;
• and,
• (2) a polyol;
• and,
• (b) a curing agent comprising:
• (1) dimethylthio-2,4-toluenediamine;
• and,
• (2) diethyl-2,4-toluenediamine.

A golf ball comprising:

• a center having a diameter of about 1.42″ and comprising 100 PPHR high cis Polybutadiene rubber, 20 PPHR Zinc Acrylate salt, 24.5 PPHR Barium Sulfate, 6 PPHR Zinc Oxide, 3 PPHR Zinc Stearate and 2.1 PPHR 1,1-Di-(tert-butylperoxy)-3,3,5-trimethyl cyclohexane (40% active);
• a thread winding layer comprised of polyisoprene rubber and having a thread size of 0.017″×5/64″ so that the thread layer thickness is about 0.08″ and the combination of the core and thread windings has a diameter of about 1.58″;
• and,
• a cover comprising 100 PPHR of prepolymer (TDI @ 6% NCO and PTMEG), 13.2 PPHR of a curative comprising Ethacure® 100 and Ethacure® 300 at a 50:50 ratio and, 2.3 PPHR pigment so that the overall ball diameter is about 1.68″.

A method of preparing a golf ball having urethane cover comprising the steps of:

• providing two matingly engageable mold halves, a first and second mold half, with at least one cavity situated within a face of each mold half;
• filling said at least one mold cavity in each mold half with a polyurethane prepolymer comprising a diisocyanate, a polyol and a curing agent comprising a slow-reacting diamine and a fast reacting diamine via a mixhead;
• transporting said two mold halves with a conveyor belt;
• arresting movement of said two mold halves on said conveyor belt with at least one guide rail and an end stop;
• positioning said first mold half below a core loading apparatus;
• securing a core to said core loading apparatus;
• positioning said core loading apparatus to align said core over a center of said at least one cavity of said first mold half;
• lowering said core into said polyurethane prepolymer situated in said at least one cavity of said first mold half so that one half of said core is submerged in said polyurethane prepolymer;
• releasing said core from said core holding apparatus;
• positioning a mold holding apparatus over said first mold half;
• lowering said mold holding apparatus over said first mold half;
• grasping said first mold half with said mold holding apparatus;
• raising said first mold half with said mold holding apparatus;
• inverting said first mold half with said mold holding apparatus;
• positioning said first mold half over said second mold half so that said at least one cavity in said first mold half is aligned with said at least one cavity in said second mold half;
• lowering said first mold half onto said second mold half;
• securing said first mold half to said second mold half such that a second half of said core is submerged in said polyurethane prepolymer situated in said at least one cavity of said second mold half;
• curing said polyurethane prepolymer;
• releasing said first mold half from said second mold half;
• removing a golf ball comprising said core and a cover comprised of polyurethane formed from said polyurethane prepolymer.