Floor board and method for manufacturing such floor boards

A floor board comprising a substrate having side edges and a decorative surface layer applied to said substrate, said substrate comprising MDF or HDF material at at least one of said side edges,

• wherein said at least one side edge is treated with an impregnation agent;
• said at least one side edge together with a side edge opposite thereto forming a first pair of opposite side edges of said substrate;
• wherein said floor board further comprises a second pair of opposite side edges;
• wherein said floor board at said first pair of opposite side edges comprises mechanical coupling parts allowing to couple said floor board at the respective edges with a similar floor board such that, in a coupled condition, said floor board and said similar floor board become locked both in a direction perpendicular to the plane formed by the coupled floor boards, as well as in a direction perpendicular to said edge and in said plane;
• wherein said mechanical coupling parts are basically shaped as a tongue and a groove, wherein said groove is delimited by an upper groove lip and a lower groove lip, and wherein said tongue and groove are provided with additional locking elements for creating said locking in the direction perpendicular to said edge and in said plane;
• and
• wherein in said coupled condition, said lower groove lip is bent-out and pushes on said tongue to thereby push the coupled floor boards towards each other;
• wherein both side edges of said first pair of opposite side edges are treated with said impregnation agent;
• wherein said mechanical coupling parts comprise a profiled contour;
• a penetration depth of said impregnation agent as measured perpendicularly to said profiled contour being larger than 0.8 millimeter, or larger than 2 millimeters along the entire contour, or always larger than 10 percent of a thickness of the substrate;
• wherein said decorative surface layer is formed from at least one or more paper layers treated with a thermosetting resin;
• or at least one or more wood veneer layers;
• wherein said impregnation agent at least penetrates the substrate immediately below said decorative surface layer.