The present invention relates to a method for producing fiber or fiber compositions comprising unsaturated bonds. These fibers eliminate dipping and curing process in producing fiber reinforced rubber and the need for the chemicals used during dipping process. These novel yarns, thus, decrease the costs of producing fiber reinforced rubber. The objective of the present invention is to produce fiber comprising unsaturated bonds which do not require treatment with RFL solution and activating chemicals in the fiber reinforced rubber materials. Reinforced rubber production will have lower production, processing and investment costs and will be more environmental friendly since RFL solution and activating chemicals are not used. Fibers with good fatigue and elongation properties can be produced without needing high twisting levels since the unsaturated fibers have higher elongation than the saturated fibers.