Patent GB-748714-A (GB)
Title: Inflatable rubber articles
Inventor: HOGG WILFRID HENRY
IPC: B05D7/22
Filed: 1953-08-21
Abstract: An inflatable rubber article such as a tyre tube or a ball is rendered less permeable to air by coating at least one surface thereof with a reaction product of a polyester and a polyisocyanate. In coating a tyre tube, a mixture of a polyester, a polyisocyanate and a plasticizer may be injected into the tube which is then squeezed between rollers to spread the mixture evenly over the tube wall, the mixture being then allowed to react at room or an elevated temperature.  If desired, accelerators such as triethylamine or urea may be added.  The polyester is preferably obtained by the condensation of a di- or polybasic acid, such as adipic, sebacic or phthalic acid, with a di- or poly-hydric alcohol such as ethylene glycol, polyethylene glycol, glycerol or pentaerythritol.  Suitable polyisocyanates are tolylene diisocyanate, hexamethylene diisocyanate, and di-(p-isocyanatophenyl) methane, and suitable compatible plasticizers are tricresyl phosphate and methyl phthalyl ethyl glycollate used in the proportion of 15 to 17 per cent by volume of the reaction product.  In mixture examples specified, each based on 30 parts by volume of a solution containing 70 per cent by weight of a condensation product of glycerol and adipic acid in butyl acetate, and 12 parts by volume of a solution containing 68 per cent by weight of di-(p-isocyanato-phenyl) methane in xylene, the plasticizer used is (1) 12 parts by volume of tricresyl phosphate, either alone or with 15 parts by volume of butyl acetate or (2) 9 parts by volume of methyl phthalyl ethyl glycollate with 15 parts by volume of butyl acetate.ALSO:An inflatable rubber article such as a tyre tube or a ball is rendered less permeable to air by coating at least one surface thereof, with a reaction product of a polyester and a polyisocyanate.  In coating a tyre tube, a mixture of a polyester, a polyisocyanate and a plasticizer may be injected into the tube which is then squeezed between rollers to spread the mixture evenly over the tube wall, the mixture being then allowed to react at room or an elevated temperature.  If desired, accelerators such as triethylamine or urea may be added.  The polyester is preferably obtained by the condensation of a di- or poly basic acid such as adipic, sebacic or phthalic acid with a di- or polyhydric alcohol such as ethylene glycol, polyethylene glycol, glycerol or pentaerythritol.  Suitable polyisocyanates are tolylene diisocyanate, hexamethylene diisocyanate, and di- (p-isocyanato-phenyl) methane, and suitable compatible plasticizers are tricresyl phosphate and methyl phthalyl ethyl glycollate used in the proportion of 15 per cent to 70 per cent by volume of the reaction product.  In mixtureexamples specified, each based on 30 parts by volume of a solution containing 70 per cent by weight of a condensation product of glycerol and adipic acid in butyl acetate, and 12 parts by volume of a solution containing 68 per cent by weight of di- (p-isocyanato-phenyl) methane in xylene, the plasticizer used is 1) 12 parts by volume of tricresyl phosphate, either alone or with 15 parts by volume of butyl acetate or 2) 9 parts by volume of methyl phthalyl ethyl glycollate with 15 parts by volume of butyl acetate.