HIGH-RIGIDITY ROAD AND PACKAGE MADE FROM SUCH BOARD Russian patent published in 2002 - IPC

FIELD: manufacture of high-rigidity boards and packages. SUBSTANCE: board consists of center part surrounded by at least one (preferably 1 to 3) outer layers on either side. Surface density of board ranges from 100 to 300 g/sq. m, bending strength factor at least 25Hm⁶/kg³, preferably 30-60Hm⁶/kg³ and Scott bond z- strength at least 100 J/sq. m. Central part of board mainly consists of chemical thermomechanical pulp at density of 200 to 450 kg. cu. m; central part has 55 to 80% of total surface density of board. Outer layers have tension resistance factor of 7.0 to 9.5 kg. Nm/g; they mainly consists of chemical pulp. EFFECT: possibility of producing board possessing combination of rigidity, surface density and z-strength; reduced power requirements. 9 cl, 2 tbl