Molded polyurethane articles having improved flex modulus and impact strength are produced by subjecting a polyurethane-forming reaction mixture which has been introduced into a mold to a static electric field. The polyalkyl ester has a specific viscosity \u03b7spc of between 5 and 30 mlg, measured in chloroform at 25\xb0 C. A hollow barrel of the body allows the launching tunnel and the rear lead shaft to be accommodated successively therein. A locking mechanism may be provided to secure the coiled fiber in the receptacle.