Bio-based polyelectrolyte complex compositions with increased hydrophobicity comprising fatty compounds

A method of treating materials selected from fiber based materials, textiles, woven and nonwoven materials the method comprising:

• a) applying to said materials an emulsion or dispersion binder composition comprising a biobased polyelectrolyte complex (PEC) composition suitable as a binder, wherein said PEC composition comprises a cationic biopolymer, an anionic biopolymer, an acid, a preservative and one or more fatty compounds, wherein,
• the net charge of the PEC composition is cationic,
• the charge ratio of the anionic biopolymer and the cationic biopolymer is ≤1,
• the cationic biopolymer is chitosan, wherein chitosan has a degree of deacetylation being 66-100%,
• the anionic biopolymer is a polyanion derived from nature,
• the acid is a Brønsted acid and/or a Lewis acid, wherein the Brønsted acid is selected from any organic and/or inorganic acids, wherein the Lewis acid is selected from any cationic mono- or multivalent atom,
• the weight ratio between cationic biopolymer and anionic biopolymer is 1:0.1 to 1:20,
• the weight ratio between the cationic biopolymer and acid is 1:0.01 to 1:30,
• the pH is less than 7,
• the one or more fatty compounds comprises one or more of sunflower oil, soy bean oil, tall oil, corn oil, rapeseed oil, coconut oil and palm oil and wherein the weight ratio of PEC:fatty compound in said PEC composition is from 1:0.5 to 1:1;
• and
• b) obtaining both an increase in a hydrophobicity of the materials and an increase in at least one mechanical property of the materials selected from dry strength, wet strength, tensile stiffness and tensile softness.