METHOD OF PRODUCING LIGNIN-PHENOL-FORMALDEHYDE RESIN Russian patent published in 2024 - IPC C08F2/04 C08G8/08 C08G8/28 

FIELD: chemical or physical processes.

SUBSTANCE: invention relates to a method of producing lignin-phenol-formaldehyde resin. Disclosed is a method of producing lignin-phenol-formaldehyde resin by mixing phenol, formaldehyde and a lignin-containing substance in an alkaline medium, lignin-containing substance used is sodium lignosulphonate, phenol, sodium lignosulphonate and alkali are dosed into the reactor, then the reaction mixture is heated to 100–130 °C and held for 1–3 hours, then the mixture is cooled to 30–50 °C, then formalin is dosed and the reaction mixture is heated to 70–80 °C and held for 1–6 hours, then the temperature of the mixture is cooled from 1 to 15 °C and maintained for another 1 to 5 hours; wherein phenol, formalin and alkali are dosed in molar ratio as 1:(1.4–2.5):(0.02–0.2), respectively, sodium lignosulphonate is also prepared in amount of 0.1 to 25% of the total weight of the prepared phenol, formalin and alkali.

EFFECT: obtaining lignin-melamine-phenol-formaldehyde resin, which provides high strength and water resistance of the adhesive joint.

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