Alloy blends of polyurethane and rubber
The present invention relates to a rubber formulation suitable for making barrier articles, such as inflatable sports balls or bicycle tubes, that resist the passage of gases, such as air, particularly as applicable to tennis balls, and more particularly to the rubber formulation which contains substantially amorphous, millable polyurethane alloyed with natural and/or synthetic rubbers.
1 . A barrier article comprising:
a) a millable polyurethane; and
b) a rubber alloyed with said millable polyurethane.
2 . The barrier article of claim 1 wherein said barrier article has an oxygen permeability not greater than (5.5 cm 3 cm/cm 2 ·s·Pa)10 −13 at 25° C.
3 . The barrier article of claim 1 wherein said barrier article has a resilience greater than 20 percent.
4 . The barrier article of claim 1 wherein said barrier article has a tensile strength greater than 500 Psi.
5 . The barrier article of claim 1 , wherein the millable polyurethane is derived from polytetramethylene ether glycol (PTMEG).
6 . The barrier article of claim 1 , wherein the rubber is selected from the group consisting of polyisoprene, polybutadiene and blends of polyisoprene and polybutadiene.
7 . The barrier article of claim 6 , wherein the rubber is polyisoprene.
8 . The barrier article of claim 7 , wherein the polyisoprene is natural or synthetic.
9 . The barrier article of claim 1 further comprising a clay component.
10 . The barrier article of claim 1 further comprising one or more additives selected from the group consisting of barium sulfate density filler, silicon dioxide, zinc oxide, zinc stearate, sulfur, N-tert-butyl-2-benzothiazole sulfenamide, phthalate ester process oils, diphenyl guanidine, benzothiazyl disulfide, zinc chloride/MBTS complex or a combination thereof.
11 . The barrier article of claim 1 , comprising at least 10% by weight of millable polyurethane.
12 . The barrier article of claim 1 , comprising between at least 10% and about 70% by weight of millable polyurethane.
13 . The barrier article of claim 1 , comprising between at least 10% and about 40% by weight of millable polyurethane.
14 . The barrier article in accordance with claim 1 , wherein the article is selected from the group consisting of inflatable balls, inflatable ball bladders, inner tubes and tubeless tires.
15 . The barrier article of claim 1 wherein the article is selected from the group consisting of a tennis ball, soccer ball bladder, volleyball bladder, basketball bladder, American football bladder, rugby ball bladder, and a bicycle inner tube.
16 . A tennis ball comprising:
a) a millable polyurethane; and
b) a rubber alloyed with said millable polyurethane.
17 . The tennis ball of claim 16 wherein the millable polyurethane and rubber alloy has an oxygen permeability not greater than (5.5 cm 3 cm/cm 2 ·s·Pa)10 −13 at 25° C.
18 . The tennis ball of claim 16 wherein the millable polyurethane and rubber alloy has a resilience greater than 20 percent.
19 . The tennis ball of claim 16 wherein the millable polyurethane and rubber alloy has a tensile strength greater than 500 Psi.
20 . The tennis ball of claim 16 , wherein the millable polyurethane is derived from polytetramethylene ether glycol (PTMEG).
21 . The tennis ball of claim 16 , wherein the rubber is selected from the group consisting of polyisoprene, polybutadiene and blends of polyisoprene and polybutadiene.
22 . The tennis ball of claim 21 , wherein the rubber is polyisoprene.
23 . The tennis ball of claim 22 , wherein the polyisoprene is natural or synthetic.
24 . The tennis ball of claim 16 wherein clay is present in the rubber in an amount up to 50% by weight of the rubber.
25 . The tennis ball of claim 16 further comprising one or more additives selected from the group consisting of barium sulfate density filler, silicon dioxide, zinc oxide, zinc stearate, sulfur N-tert-butyl-2benzothiazolesulfenamide, phthalate ester process oils, diphenyl guanidine, benzothiazyl disulfide, zinc chloride/MBTS complex or a combination thereof.
26 . The tennis ball of claim 16 , comprising at least 10% by weight of millable polyurethane.
27 . The tennis ball of claim 16 , comprising between at least 10% and about 40% by weight of millable polyurethane.