A biocide resin composition that includes one or more solutions of selected melamine-formaldehyde, urea-formaldehyde, phenol-formaldehyde, melamine-urea-formaldehyde, and phenolic resins, and more than one copper salt soluble in aqueous systems and melamine-formaldehyde, urea-formaldehyde, and phenolic solutions. Copper salts are of the copper citrate, copper lysinate, copper gluconate, copper salicylate, copper phthalocyanine, copper chelate, copper oxalate, copper acetate, copper methionine, copper tartrate, copper glycinate, copper picolinate, copper aspartate, ammoniacal copper complexes, EDTA (ethylenediaminetetraacetic acid)-copper complexes, copper glycolate, copper glycerate, copper ascorbate type and, in general, copper salts of the organic type, R—Cu, R1-Cu—R2, where R, R1, and R2 can be alkyl chains (C3-C18) with one or more acid, aldehyde, ester, ether, hydroxyls, amino, or others groups in its structure.