▎ 摘　　要

NOVELTY - Preparing furan resin comprises e.g. (i) taking 20-60 pts. wt. lignin, 4-10 pts. wt. maleic anhydride, 6-14 pts. wt. xylitol, 15-55 pts. wt. graphene, 15-55 pts. wt. furfuryl alcohol, 4-10 pts. wt. furanone, 30-80 pts. wt. solid formaldehyde, 0.5-2 pts. wt. coupling agent, 4-12 pts. wt. urea, 0.5-1 pts. wt. metal salt, 2-6 pts. wt. boric acid and 0.1-0.4 pts. wt. benzoic acid; (ii) heating and stirring lignin, maleic anhydride and xylitol in stirrer to prepare modified lignin; (iii) mixing graphene and furfuryl alcohol to obtain graphene dispersant; (iv) stirring solid formaldehyde and urea in reaction kettle, adding boric acid and adjusting pH value with benzoic acid; (v) carrying out catalytic reaction of graphene dispersant and furanone under acidic condition; (vi) adding sodium hydroxide solution to adjust pH, reacting, adding modified lignin and reacting; (vii) cooling, adding coupling agent and stirring; and (viii) adding metal salt and stirring. USE - The method is useful for preparing furan resin. ADVANTAGE - The method: uses solid formaldehyde and furfurone to react and can consume the formaldehyde generated during the production process thus free formaldehyde content of the product is reduced to 0.09%; and adds boric acid to improve the graphitization degree and wear and thermal shock resistance of furan resin with reduced the brittleness and better toughness and bonding strength. DETAILED DESCRIPTION - Preparing furan resin comprises (i) taking 20-60 pts. wt. lignin, 4-10 pts. wt. maleic anhydride, 6-14 pts. wt. xylitol, 15-55 pts. wt. graphene, 15-55 pts. wt. furfuryl alcohol, 4-10 pts. wt. furanone, 30-80 pts. wt. solid formaldehyde, 0.5-2 pts. wt. coupling agent, 4-12 pts. wt. urea, 0.5-1 pts. wt. metal salt, 2-6 pts. wt. boric acid and 0.1-0.4 pts. wt. benzoic acid, the lignin purity is more than 92% chosen from at least one of coniferous, broad-leaved and/or vegetation lignin, the xylitol is chosen from at least one of corn core, rice straw and sugar cane, the solid formaldehyde is paraformaldehyde with low polymerization degree and the content is 90-99.9% and the furanone comprises furfuryl acetone and/or difurfuryl acetone; (ii) taking lignin, maleic anhydride and xylitol, placing in the stirrer, heating to 90-120degrees Celsius and stirring at 90-120degrees Celsius for 15-30 minutes to prepare the modified lignin; (iii) mixing the graphene and furfuryl alcohol to obtain graphene dispersant; (iv) adding the solid formaldehyde and urea into the reaction kettle, starting the stirrer to stir and mix, adding boric acid and adjusting the pH value to 4-5 with benzoic acid; (v) adding the graphene dispersant and furanone under the acidic condition, introducing steam to heat to 20degrees Celsius/10 minutes, heating to 100-120degrees Celsius and carrying out catalytic reaction at 100-120degrees Celsius for 1.5-2.5 hours; (vi) adding sodium hydroxide solution to adjust the pH to 7-9, reacting for 1-2 hours at 80-100degrees Celsius, adding the modified lignin and reacting at 80-90degrees Celsius for 1 hour; (vii) cooling to 50-60degrees Celsius, adding coupling agent and stirring for 25-40 minutes; and (viii) adding metal salt and stirring for 25-40 minutes.