Multi-layered lignocellulosic molded bodies with low formaldehyde emissions

摘要

Multi-layered lignocellulosic molded bodies comprising A) a middle layer or multiple middle layers containing lignocellulosic particles, said layer/layers obtained through the use of a binder (a) and B) a cover layer or multiple cover layers containing lignocellulosic particles, said layer or layers obtained through the use of a binder (b), wherein a binder (a) is selected from the group consisting of (a1) formaldehyde resins and (a2) an organic isocyanate with at least two isocyanate groups; wherein binder (b) contains the following components: an aqueous component (I) comprising (i) a polymer A constructed of the following monomers: a) 70 to 100 wt.-% of at least one ethylenically unsaturated mono and/or dicarboxylic acids (monomer(s) A1 ) and b) 0 to 30 wt.-% of at least one other ethylenically unsaturated monomers that differs from monomers A1 (monomer(s) A2) and optionally (ii) a low molecular weight cross-linking agent comprising at least two functional groups selected from the group of hydroxy, carboxylic acid and derivatives thereof, primary, secondary and tertiary amine, epoxy, aldehyde and optionally a component (II) as an aqueous dispersion comprising one or more polymer(s) M constructed from the following monomers: a) 0 to 50 wt.-% of at least one ethylenically unsaturated monomer containing an epoxide group and/or at least one hydroxyalkyl group (monomer(s) M1), and b) 50 to 100 wt.-% of at least one other ethylenically unsaturated monomer that differs from monomer M1 (monomer(s) M2) and optionally conventional additives as component (III) and wherein binder (b) contains formaldehyde traps in case binder (a) contains a formaldehyde resin.