Polyurethane glue single-component neutral color.

Polyurethane prepolymer, which is obtained by reacting at least one aromatic polyisocyanate having symmetrical substitution in respect of NCO groups and at least one aromatic polyisocyanate having asymmetric substitution in respect to NCO groups, the ratio of aromatic polyisocyanate having symmetrical substitution in respect of NCO groups, or the ratio of the mixture formed by two or more of these aromatic polyisocyanates, greater than the proportion of the aromatic polyisocyanate , having asymmetric substitution in respect of NCO groups or greater than the proportion of the mixture of two or more such aromatic polyisocyanates and at least one polyol having an OH functionality greater than 2, 5 and a molecular weight of 1,000 or below this value and at least one polyol with a less than 2, 5 OH functionality and a molecular weight of 1,000 or in top of this value.