Method for producing modified wooden material, 5-hmf resinification solution, and modified wooden material

A method of producing a modified wooden material, comprising the steps of:

• 1) impregnating a wooden material with a 5-hydroxymethylfurfural (5-HMF) and 5-HMF-resinification solution comprising an inorganic salt and/or hydrate or anhydride thereof, and/or an organic acid and/or an anhydride or salt that can be formed from the organic acid, which accelerate the polymerization of at least a portion of 5-HMF and/or the adhesion of 5-HMF to the wooden material;
• and
• 2) polymerizing at least a portion of 5-HMF of the 5-HMF resinification solution impregnated into the wooden material in the wooden material and/or adhering that to the wooden material.