Cold-pressed mats of lignocellulosic material having improved cold tack and a process for their production

A cold-pressed mat of a lignocellulosic material having a Push Off Test extension equal to at least 85% of that of a mat made with a urea-formaldehyde resin, which is produced at ambient temperature by a process comprising:

• (a) separately adding each component of a binder system comprising:
• (i) a polymeric derivative of diphenylmethane diisocyanate or a prepolymer of a polymeric derivative of diphenylmethane diisocyanate having an NCO functionality of from 2.2 to 3.3 and a viscosity of from 25 to 2,000 mPas
• and
• (ii) at least one aqueous dispersion of a material having adhesive or tackifying characteristics when contacted with lignocellulosic material to the lignocellulosic material;
• (b) blending each of the components of the binder system and the lignocellulosic material until the lignocellulosic material is sufficiently coated with the binder system components that the lignocellulosic material can be formed into a mat;
• (c) forming the coated lignocellulosic material into a mat;
• and
• (d) applying sufficient pressure to the mat at ambient temperature to form a mat having a desired thickness.