Patent ID: 11891410
Assignee: UPM-KYMMENE CORPORATION
Field: Biotechnology (Chemistry)
Classification: CPC C | IPC C

Claim 20:
21. A high-pressure laminate obtainable by a method comprising:
forming a binder composition by
a) dissolving lignin into an aqueous composition, which includes a compound selected from the class of phenols, while keeping the temperature of the composition at 0-60° C. and the pH of the composition at a pH value of 4-9.5, the lignin being kraft lignin,
b) subsequently allowing the dissolved lignin from step a) to react with the compound selected from the class of phenols and to react with alkali, wherein the alkali comprises a hydroxide of an alkali metal, while keeping the temperature of the composition at 60-100° C. and the pH of the composition at a pH value of 6-9.5 for alkalating lignin, and
c) adding a cross-linking agent to the composition formed in step b), mixing the crosslinking agent and the composition formed in step b) to form a mixture, and heating the mixture at a temperature of 60-100° C. while keeping the pH of the composition at a pH value of 6-9.5 for polymerizing the lignin, the compound selected from the class of phenols, and the crosslinking agent;

impregnating at least two layers of Kraft paper with the binder composition; and
fusing together the impregnated layers of Kraft paper under heating and pressure to form the high-pressure laminate.