PURPOSE: To improve the crosslinking degree of an olefinic resin in the form of fiber and improve the heat-resistance, abrasion resistance and flexural resistance without deteriorating other characteristics by grafting a silane to an olefinic resin, incorporating the grafted resin with an agent for suppressing the deposition of sticky material and extruding the mixture.

CONSTITUTION: A silane compound is grafted to an olefinic resin such as polyethylene or polypropylene in the presence of a radical generator, the grafted resin is blended with a silanol condensation catalyst and 0.5-2.5wt.% of an agent for suppressing the deposition of sticky material and the mixture is extrusion molded to obtain a monofilament. The crosslinking degree (gel fraction) of the monofilament is increased to ≥55% by treating with hot steam or in a hot water of ≥50°C. The crosslinking degree can be increased without deteriorating the hydrophobicity, the chemical resistance and the surface softness of the olefinic resin and the obtained resin is useful for a washing or polishing brush, a fish shelter, a filtration mesh, etc.