Manufacture of polyurethane foam ball

1. A method for manufacturing a cellular elastomeric polyurethane foam ball which comprises (1) forming a reaction mixture comprising a first composition and a second composition inside a spherical mold, (2) maintaining the reaction mixture inside the mold at reaction conditions including a temperature of from about 60 to about 80° C. for a time sufficient to form a cellular elastomeric polyurethane foam ball inside the mold, (3) removing the formed cellular elastomeric polyurethane foam ball from the mold, and (4) curing the formed cellular elastomeric polyurethane foam ball at a temperature for from about 60 to about 80° C. for a time of from about 60 minutes to about 12 hours, the resulting foam ball having a diameter of from about 59 to about 62 mm, a weight of from about 41 to about 45 g, a bound of from about 150 to about 180 cm when dropped from 254 cm onto horizontal, level concrete, and a forward deformation of from about 5 to about 11 mm, measured by first compressing the ball to a 25.4 mm deformation on each of the three orthogonal axes, then compressing the ball at a rate of 50.8 mm/min until a 1.36 kg load was achieved, increasing the load to 9.53 kg, and measuring the deformation from the 1.36 kg load, said first composition of the reaction mixture comprising at least one isocyanate compound and said second composition of the reaction mixture comprising at least one compound containing a functional group which is reactive with the at least one isocyanate compound of the first composition; a chain extender; at least one catalyst or catalyst mixture comprising a tertiary amine and, optionally, a metal complex, said metal of the metal complex being selected from the group consisting of tin, titanium, zirconium, zinc, bismuth, mercury, iron and combinations thereof; optionally at least one nonionic surfactant; and at least one blowing agent, wherein the chain extender of the second composition comprises an aromatic diamine selected from a group consisting of 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; diethyltoluene diamine; and combinations thereof.

2. The method of claim 1 wherein the isocyanate compound of the first composition is selected from the group consisting of methylene diphenylene diisocyanate; dimer, trimer and allophanate of hexamethylene diisocyanate; toluene diisocyanate; trimer of toluene diisocyanate; and combinations thereof.

3. The method of claim 1 wherein the compound of the second composition containing a functional group which is reactive with the isocyanate compound of the first composition is selected from the group consisting of polytetramethylene ether glycol; alkylene oxide copolymer of ethylene oxide and tetrahydrofuran; polypropylene glycol; polyethylene glycol; and combinations thereof.

4. The method of claim 1 wherein the chain extender of the second composition is a combination of water, and said aromatic diamine.

5. The method of claim 1 wherein the chain extender of the second composition comprises a mixture of 3,5-dimethylthio-2,4-toluenediamine and 3,5-dimethylthio-2,6-toluenediamine.

6. The method of claim 1 wherein the reaction mixture comprises from about 0.05 to about 0.50 wt. % tertiary amine and from about 0 to about 0.50 wt. % metal complex provided by the catalyst or catalyst mixture of the second composition.

7. The method of claim 6 wherein the tertiary amine comprises 1,4-diazabicyclo[2.2.2]octane, and the metal complex is selected from the group consisting of dibutyl tin dilaurate; tinoctoate; a titanium complex; and a bismuth complex.

8. The method of claim 1 wherein the nonionic surfactant of the second composition is selected from the group consisting of polydialkylsiloxane; a copolymer of polydialkylsiloxane; polyalkyleneoxide; a copolymer of polyalkyleneoxide; and combinations thereof.

9. The method of claim 1 wherein the blowing agent of the second composition is selected from the group consisting of water, pentane, carbonic acid and combinations thereof.

10. The method of claim 1 wherein the reaction conditions of step (2) include a time of from about 5 to about 20 minutes.

11. The method of claim 1 wherein the weight ratio of first composition to second composition in the reaction mixture is from about 18/82 to about 24/76.

12. The method of claim 1 wherein the reaction mixture comprises from about 70 to about 82 wt. % compound containing a functional group which is reactive with the isocyanate compound of the first composition; from about 0 to about 6.0 wt. % chain extender; from about 0.1 to about 1.0 wt. % catalyst or catalyst mixture; from about 0 to about 1.0 wt. % nonionic surfactant; and from about 0.2 to about 0.4 wt. % water.

13. A cellular elastomeric polyurethane foam ball manufactured by the method which comprises (1) forming a reaction mixture comprising a first composition and a second composition inside a spherical mold, (2) maintaining the reaction mixture inside the mold at reaction conditions including a temperature of from about 60 to about 80° C. for a time sufficient to form a cellular elastomeric polyurethane foam ball inside the mold, (3) removing the formed cellular elastomeric polyurethane foam ball from the mold, and (4) curing the formed cellular elastomeric polyurethane foam ball at a temperature for from about 60 to about 80° C. for a time of from about 60 minutes to about 12 hours, the resulting foam ball having a diameter of from about 59 to about 62 mm, a weight of from about 41 to about 45 g, a bound of from about 150 to about 180 cm when dropped from 254 cm onto horizontal, level concrete, and a forward deformation of from about 5 to about 11 mm, measured by first compressing the ball to a 25.4 mm deformation on each of the three orthogonal axes, then compressing the ball at a rate of 50.8 mm/min until a 1.36 kg load was achieved, increasing the load to 9.53 kg, and measuring the deformation from the 1.36 kg load, said first composition of the reaction mixture comprising at least one isocyanate compound and said second composition of the reaction mixture comprising at least one compound containing a functional group which is reactive with the at least one isocyanate compound of the first composition; a chain extender; at least one catalyst or catalyst mixture comprising a tertiary amine and, optionally, a metal complex, said metal of the metal complex being selected from the group consisting of tin, titanium, zirconium, zinc, bismuth, mercury, iron and combinations thereof; optionally at least one nonionic surfactant; and at least one blowing agent, wherein the chain extender of the second composition comprises an aromatic diamine selected from a group consisting of 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; diethyltoluene diamine; and combinations thereof.

14. The cellular elastomeric polyurethane foam ball of claim 13 having a weight of from about 41 to about 45 grams; a diameter of from about 59 to about 62 mm; a bound of from about 150 to about 170 cm when dropped from 254 cm onto horizontal, level concrete; a forward deformation of from about 6 to about 8 mm, measured by first compressing the ball to a 25.4 mm deformation on each of the three orthogonal axes, then compressing the ball at a rate of 50.8 mm/min until a 1.36 kg load was achieved, increasing the load to 9.53 kg, and measuring the deformation from the 1.36 kg load: and a return deformation of from about 9 to about 11 mm, measured by first compressing the ball to a deformation of 25.4 mm, reducing the load to 9.53 kg to determine an initial deformation, reducing the load again to 1.36 kg and measuring the difference in deformation.

15. The cellular elastomeric polyurethane foam ball of claim 13 wherein the isocyanate compound of the first composition is selected from the group consisting of methylene diphenylene diisocyanate; dimer, trimer and allophanate of hexamethylene diisocyanate; toluene diisocyanate; trimer of toluene diisocyanate; and combinations thereof.

16. The cellular elastomeric polyurethane foam ball of claim 13 wherein the compound of the second composition containing a functional group which is reactive with the isocyanate compound of the first composition is selected from the group consisting of polytetramethylene ether glycol; alkylene oxide copolymer of ethylene oxide and tetrahydrofuran; polypropylene glycol; polyethylene glycol; and combinations thereof.

17. The cellular elastomeric polyurethane foam ball of claim 13 wherein the chain extender of the second composition is a combination of water and said aromatic diamine.

18. The cellular elastomeric polyurethane foam ball of claim 13 wherein the chain extender of the second composition is comprises a mixture of 3,5-dimethylthio-2,4-toluenediamine and 3,5-dimethylthio-2,6-toluenediamine.

19. The cellular elastomeric polyurethane foam ball of claim 13 wherein the reaction mixture comprises from about 0.05 to about 0.50 wt. % tertiary amine and from about 0 to about 0.50 wt. % metal complex provided by the catalyst or catalyst mixture of the second composition, the metal complex being selected from the group consisting of dibutyl tin dilaurate; tinoctoate; a titanium complex; and a bismuth complex.

20. A tennis ball comprising the cellular elastomeric polyurethane foam ball of claim 14 as a core and felt as covering, said tennis ball having a weight of from 56.70 to 58.47 grams; a diameter of from 65.4 to 68.6 mm; a bound of from 135 to 147 cm when dropped from 254 cm onto horizontal, level concrete; a forward deformation of from 5.59 to 7.37 mm, measured by first compressing the ball to a 25.4 mm deformation on each of the three orthogonal axes, then compressing the ball at a rate of 50.8 mm/min until a 1.36 kg load was achieved, increasing the load to 9.53 kg, and measuring the deformation from the 1.36 kg load; and a return deformation of from 8.89 to 10.8 mm, measured by first compressing the ball to a deformation of 25.4 mm, reducing the load to 9.53 kg to determine an initial deformation, reducing the load again to 1.36 kg and measuring the difference in deformation.