Formaldehyde-free binder and use for mineral wool insulation products

A process for manufacturing a formaldehyde-free binder composition comprising the steps of:

• (a) preparing a dispersion of starch, wherein an amount of 95 weight % or more of the starch is water-insoluble native starch, in water at a temperature of 10 to 40° C.;
• and
• (b) contacting the dispersion obtained in step (a) with an acrylic component at a temperature of 10 to 40° C. selected from the group consisting of polyacrylic acid, copolymers of acrylic and maleic acids, copolymers of ethylene-unsaturated moieties containing at least 10 mol % of acrylic acid, maleic acid or maleic anhydride;
• salts of any preceding (co)polymers, curable resins based on the preceding (co)polymers, and mixtures thereof.

A process for producing a mineral wool product containing a cured formaldehyde-free binder comprising

• preparing an aqueous binder composition in the form of a dispersion comprising a) starch, wherein an amount of 95 weight % or more of the starch is water-insoluble native starch;
• and b) one or more acrylic component(s), selected from the group consisting of polyacrylic acid, copolymers of acrylic and maleic acids, copolymers of ethylene-unsaturated moieties containing at least 10 mol % of acrylic acid, maleic acid or maleic anhydride;
• salts of any preceding (co)polymers, curable resins based on any preceding (co)polymers, and mixtures thereof;
• impregnating mineral fibers of the mineral wool product with the aqueous binder composition with a solid content of 4 to 10 weight %;
• and
• curing the aqueous binder composition at a temperature above 100° C.