Patent ID: 7985780

Claim:
A cylindrical molding comprising a cellular polyurethane elastomer wherein said cellular polyurethane elastomer is the reaction product of (i) a prepolymer having isocyanate groups and which is based on (a) methylenediphenyl diisocyanate, and (b1) polyetherdiol having a molecular weight of from 1500 g/mol to 3000 g/mol and which is based on propylene oxide and/or ethylene oxide; with (ii) a crosslinking component comprising (b2) polyetheralcohol having a nominal functionality with respect to isocyanates of from 2 to 3 and a molecular weight of from 1500 g/mol to 6000 g/mol and which is based on propylene oxide and/or ethylene oxide, (c2) diol having a molecular weight of from 62 g/mol to 499 g/mol, (d) water, and (e) catalysts; wherein (b1) and (b2) have an average polyol molar mass of from 3000 g/mol to 3700 g/mol, said average polyol molar mass M (Polyol) being calculated according to the following formula: M _ ⁡ ( Polyol ) = ( M b ⁢ ⁢ 11 · m b ⁢ ⁢ 11 + … + M b ⁢ ⁢ 1 ⁢ ⁢ n · m b ⁢ ⁢ 1 ⁢ n ⁢ ) · W p + ( M b ⁢ ⁢ 21 · m b ⁢ ⁢ 21 + … + M b ⁢ ⁢ 2 ⁢ ⁢ n · m b ⁢ ⁢ 2 ⁢ ⁢ n ) · W v ( m b ⁢ ⁢ 11 + … + m b ⁢ ⁢ 1 ⁢ ⁢ n ) · W p + ( m b ⁢ ⁢ 21 + … + m b ⁢ ⁢ 2 ⁢ ⁢ n ) · W v wherein M (Polyol) is average polyol molar mass in g/mol M b11 (or M b1n ) is molar mass of polyol b11 (or polyol b1n) in the prepolymer (i) in g/mol M b11 (or M b1n ) is mass fraction of polyol b11 (or polyol b1n) in the prepolymer (i) in g/g W P : is mass fraction of the prepolymer (i) in the cylindrical molding in g/g M b21 (or M b2n ): is molar mass of polyol b21 (or polyol b2n) in the crosslinking component (ii) in g/mol m b21 (or m b2n ): is mass fraction of polyol b21 (or polyol b2n) in the crosslinking component (ii) in g/g W V : is mass fraction of the crosslinking component (ii) in the cylindrical molding in g/g wherein said cellular polyurethane elastomers have a density, according to DIN EN ISO 845, of from 300 to 900 kg/m 3 ; a tensile strength, according to DIN EN ISO 1798, of greater than or equal to 2.0 N/mm 2 ; an elongation at break, according to DIN EN ISO 1798, of greater than or equal to 200%; and a tear propagation resistance, according to DIN ISO 34-1 B (b), of greater than or equal to 8 N/mm.