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CN-121991612-A - Lignin adhesive, preparation method and application thereof

CN121991612ACN 121991612 ACN121991612 ACN 121991612ACN-121991612-A

Abstract

The invention relates to the technical field of adhesives, in particular to a lignin adhesive, a preparation method and application thereof. The preparation method of the lignin adhesive comprises the following steps of S1, mixing a component a with 5-hydroxymethylfurfural to obtain a eutectic solvent, wherein the component a comprises choline chloride and/or betaine, and S2, uniformly mixing the eutectic solvent with lignin, and heating for polymerization reaction to obtain the lignin adhesive. The lignin adhesive has higher bonding strength to the poplar board and the phyllostachys pubescens board at room temperature, and the cementing piece after the lignin adhesive is solidified has excellent water resistance and boiling resistance. The preparation method is simple to operate, raw materials are completely derived from biomass, phenol and formaldehyde are not contained, and the preparation method is environment-friendly and has a wide application prospect in the field of wood bonding.

Inventors

  • YAN LIFENG
  • ZHAN BOXIANG

Assignees

  • 中国科学技术大学

Dates

Publication Date
20260508
Application Date
20260320

Claims (10)

  1. 1. The preparation method of the lignin adhesive comprises the following steps: S1, mixing a component a with 5-hydroxymethylfurfural to obtain a eutectic solvent, wherein the component a comprises choline chloride and/or betaine; S2, uniformly mixing the eutectic solvent and lignin, and heating to perform polymerization reaction to obtain the lignin adhesive.
  2. 2. The preparation method according to claim 1, wherein in the step S1, the molar ratio of the component a to the 5-hydroxymethylfurfural is 1:1-3.
  3. 3. The method according to claim 1, wherein in step S1, the mixing temperature is 80 to 100 ℃ and the mixing time is 10 to 30 min.
  4. 4. The preparation method according to claim 1, wherein in the step S2, the mass ratio of the eutectic solvent to lignin is 1:0.3-0.7; the lignin comprises at least one of straw lignin, rice hull lignin and corncob lignin.
  5. 5. The method according to claim 1, wherein in step S2, the homogenized raw material further comprises a catalyst; the catalyst is an alkaline catalyst and comprises at least one of sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate.
  6. 6. The preparation method according to claim 5, wherein the mass of the catalyst is 0-1% of the total mass of the eutectic solvent and lignin.
  7. 7. The preparation method according to claim 1, wherein in the step S2, the temperature of the uniform mixing is 80-100 ℃ and the time is 5-10 min.
  8. 8. The method according to claim 1, wherein in the step S2, the polymerization reaction is performed at 120 to 180 ℃ for 0.5 to 6 hours.
  9. 9. The lignin adhesive prepared by the method of any one of claims 1 to 8.
  10. 10. Use of the lignin adhesive according to claim 9 as a wood adhesive.

Description

Lignin adhesive, preparation method and application thereof Technical Field The invention relates to the technical field of adhesives, in particular to a lignin adhesive, a preparation method and application thereof. Background The adhesive is widely applied to the market, especially in furniture which people often contact. The adhesives commonly used in the market are mainly urea-formaldehyde resin and phenolic resin adhesives, and the two adhesives contain free formaldehyde, and the preparation process is complex and the cost is high. In order to solve the problem of formaldehyde release caused by the traditional petroleum-based phenolic resin and urea-formaldehyde resin adhesives, the development of green and nontoxic alternative adhesives by using renewable biomass resources has become a research hot spot. The prior art uses lignin to replace phenol in traditional phenolic resin, but most adhesives using lignin need to be modified variously due to low self-reactivity of lignin or partially replaced by lignin. In this way, the process is complicated, and the process cost is increased. Moreover, most adhesives in the related art continue to use formaldehyde to react with lignin, and some use less toxic furfural or glyoxal to replace formaldehyde. The use of low toxicity aldehydes instead of formaldehyde is indeed environmentally friendly, but the overall performance is still to be improved. In order to realize the direct and efficient utilization of lignin, researchers often adopt bio-based aldehyde compounds (such as vanillin, ethyl vanillin and the like) to replace formaldehyde, and the bio-based aldehyde compounds and the lignin undergo a polymerization reaction to prepare the adhesive. However, the water resistance, especially the durability against boiling water digestion, of most bio-based aldehyde-lignin adhesive systems still cannot meet the use requirements under high humidity or outdoor environments, which severely restricts their application in practical engineering. Disclosure of Invention In view of the above, the technical problem to be solved by the invention is to provide a lignin adhesive, a preparation method and application thereof, wherein the lignin adhesive has higher bonding strength to poplar boards and moso bamboo boards at room temperature, and an adhesive joint piece after the lignin adhesive is cured has excellent water resistance and boiling resistance. The invention provides a preparation method of lignin adhesive, which comprises the following steps: S1, mixing a component a with 5-hydroxymethylfurfural to obtain a eutectic solvent, wherein the component a comprises choline chloride and/or betaine; S2, uniformly mixing the eutectic solvent and lignin, and heating to perform polymerization reaction to obtain the lignin adhesive. Preferably, in the step S1, the molar ratio of the component a to the 5-hydroxymethylfurfural is 1:1-3. Preferably, in step S1, the temperature of the mixing is 80-100 ℃ and the time is 10-30 min. Preferably, in the step S2, the mass ratio of the eutectic solvent to the lignin is 1:0.3-0.7; the lignin comprises at least one of straw lignin, rice hull lignin and corncob lignin. Preferably, in step S2, the uniformly mixed raw materials further include a catalyst; the catalyst is an alkaline catalyst and comprises at least one of sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate. Preferably, the mass of the catalyst accounts for 0-1% of the total mass of the eutectic solvent and lignin. Preferably, in step S2, the temperature of the uniform mixing is 80-100 ℃ and the time is 5-10 min. Preferably, in the step S2, the polymerization reaction temperature is 120-180 ℃, and the polymerization reaction time is 0.5-6 hours. The invention also provides the lignin adhesive prepared by the preparation method. The invention also provides an application of the lignin adhesive as a wood adhesive. The preparation method provided by the invention is simple to operate, raw materials are completely derived from biomass, phenol and formaldehyde are not contained, and the preparation method is environment-friendly and has a wide application prospect in the field of wood bonding. The lignin adhesive has higher bonding strength to the poplar board and the phyllostachys pubescens board at room temperature, and the bonding strength is far more than the national standard of the phenolic resin wood adhesive (the bonding strength is more than or equal to 0.7MPa (GB/T14732-2017)). The cementing piece cured by the lignin adhesive has excellent water resistance and boiling resistance, and the performance of the cementing piece is far superior to most of the biological-based adhesives on the market at present. Specifically, the adhesive test sample after the lignin adhesive is solidified can still maintain higher strength retention rate after being soaked in water for 24 hours, and shows excellent water resistance. After the glue joint sample solidif