Novel tennis ball

Abstract

Tennis ball which comprises an elastomeric polyurethane foam having a ball shape and a density of 250-800 kg/m 3 , which foam is covered with a textile material.

1 . Tennis ball which comprises an elastomeric polyurethane foam having a ball shape and a density of 250-800 kg/m 3 , which foam is covered with a textile material and which foam has been prepared by reacting an aromatic polyisocyanate and a polyol comprising at least 30% by weight of a polyol having a level of unsaturation of at most 0.03 meq/g and using a blowing agent, wherein the polyol having a level of unsaturation of at most 0.03 meq/g is selected from polyester polyols, polyoxypropylene polyols, polyoxyethylene polyoxypropylene polyols, polyoxyethylene polyols, polyoxybutylene polyols, polyoxyalkylene polyols comprising oxybutylene groups together with oxyethylene and/or oxypropylene groups, polyoxyalkylene polyester polyols and mixtures of such polyols with the proviso that the use of a polyoxyethylene polyoxypropylene polyol having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, as the only polyol having a level of unsaturation of at most 0.03 meq/g is excluded. 
     
     
         2 . Tennis ball according to  claim 1  wherein the polyol has an average nominal functionality of 2-4 and an average molecular weight of 1000-8000. 
     
     
         3 . Tennis ball according to  claim 1  wherein the polyol is selected from polyester polyols, polyoxybutylene polyols, polyoxyalkylene polyester polyols and mixtures of these polyols and mixtures of the aforementioned polyols with polyoxyethylene polyoxypropylene polyols having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, in a weight ratio of the aforementioned polyols:this polyoxyethylene polyoxypropylene polyol of 1:99 to 99:1. 
     
     
         4 . Process for preparing a tennis ball according to  claim 1  comprising making a ball-shaped elastomeric polyurethane foam by putting an aromatic polyisocyanate, a polyol comprising at least 30% by weight of a polyol having a level of unsaturation of at most 0.03 meq/g and a blowing agent into a ball-shaped mould and by allowing these ingredients to form the elastomeric polyurethane foam, removing the foam from the mould and covering the foam with a textile material, wherein the polyol having a level of unsaturation of at most 0.03 meq/g is selected from polyester polyols, polyoxypropylene polyols, polyoxyethylene polyoxypropylene polyols, polyoxyethylene polyols, polyoxybutylene polyols, polyoxyalkylene polyols comprising oxybutylene groups together with oxyethylene and/or oxypropylene groups, polyoxyalkylene polyester polyols and mixtures of such polyols with the proviso that the use of a polyoxyethylene polyoxypropylene polyol having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, as the only polyol having a level of unsaturation of at most 0.03 meq/g is excluded. 
     
     
         5 . Process according to  claim 4  wherein the polyol has an average nominal functionality of 2-4 and an average molecular weight of 1000-8000. 
     
     
         6 . Process according to  claim 4  wherein the polyol is selected from polyester polyols, polyoxybutylene polyols, polyoxyalkylene polyester polyols and mixtures of these polyols and mixtures of the aforementioned polyols with polyoxyethylene polyoxypropylene polyols having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, in a weight ratio of the aforementioned polyols:this polyoxyethylene polyoxypropylene polyol of 1:99 to 99:1. 
     
     
         7 . Tennis ball according to  claim 2  wherein the polyol is selected from polyester polyols, polyoxybutylene polyols, polyoxyalkylene polyester polyols and mixtures of these polyols and mixtures of the aforementioned polyols with polyoxyethylene polyoxypropylene polyols having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, in a weight ratio of the aforementioned polyols:this polyoxyethylene polyoxypropylene polyol of 1:99 to 99:1. 
     
     
         8 . Process for preparing a tennis ball according to  claim 2  comprising making a ball-shaped elastomeric polyurethane foam by putting an aromatic polyisocyanate, a polyol comprising at least 30% by weight of a polyol having a level of unsaturation of at most 0.03 meq/g and a blowing agent into a ball-shaped mould and by allowing these ingredients to form the elastomeric polyurethane foam, removing the foam from the mould and covering the foam with a textile material, wherein the polyol having a level of unsaturation of at most 0.03 meq/g is selected from polyester polyols, polyoxypropylene polyols, polyoxyethylene polyoxypropylene polyols, polyoxyethylene polyols, polyoxybutylene polyols, polyoxyalkylene polyols comprising oxybutylene groups together with oxyethylene and/or oxypropylene groups, polyoxyalkylene polyester polyols and mixtures of such polyols with the proviso that the use of a polyoxyethylene polyoxypropylene polyol having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, as the only polyol having a level of unsaturation of at most 0.03 meq/g is excluded. 
     
     
         9 . Process for preparing a tennis ball according to  claim 3  comprising making a ball-shaped elastomeric polyurethane foam by putting an aromatic polyisocyanate, a polyol comprising at least 30% by weight of a polyol having a level of unsaturation of at most 0.03 meq/g and a blowing agent into a ball-shaped mould and by allowing these ingredients to form the elastomeric polyurethane foam, removing the foam from the mould and covering the foam with a textile material, wherein the polyol having a level of unsaturation of at most 0.03 meq/g is selected from polyester polyols, polyoxypropylene polyols, polyoxyethylene polyoxypropylene polyols, polyoxyethylene polyols, polyoxybutylene polyols, polyoxyalkylene polyols comprising oxybutylene groups together with oxyethylene and/or oxypropylene groups, polyoxyalkylene polyester polyols and mixtures of such polyols with the proviso that the use of a polyoxyethylene polyoxypropylene polyol having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, as the only polyol having a level of unsaturation of at most 0.03 meq/g is excluded. 
     
     
         10 . Process according to  claim 5  wherein the polyol is selected from polyester polyols, polyoxybutylene polyols, polyoxyalkylene polyester polyols and mixtures of these polyols and mixtures of the aforementioned polyols with polyoxyethylene polyoxypropylene polyols having an oxyethylene content of 50-90% by weight, calculated on the weight of the polyol, in a weight ratio of the aforementioned polyols:this polyoxyethylene polyoxypropylene polyol of 1:99 to 99:1.