Degraded condensed tannin modified phenolic resin wood adhesive and preparation method thereof

A technology for wood adhesives and condensed tannins, applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesives, adhesive types, etc. Problems such as high cost increase and unsuitable synthesis of phenolic resin adhesives have achieved the effect of high-value and high-efficiency utilization, high industrial feasibility, and rapid curing

Inactive Publication Date: 2020-08-25
NANJING FORESTRY UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the nucleophiles used in the process of acid-assisted degradation of condensed tannins mainly include thiols and active phenolic rings, among which thiols have a pungent odor, and the covalent bonds formed between them and carbocation intermediates It is unstable when the pH value is higher than 8.5, so it is not suitable for the synthesis of phenolic resin adhesives under alkaline conditions
The C-C bond formed between the active phenolic rings and the carbocation intermediate is relatively stable under alkaline conditions, but its large addition will lead to a high cost of degrading condensed tannins, so it cannot be selected as an acid-assisted degradation of condensed tannins nucleophile

Method used

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  • Degraded condensed tannin modified phenolic resin wood adhesive and preparation method thereof
  • Degraded condensed tannin modified phenolic resin wood adhesive and preparation method thereof

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preparation example Construction

[0039] to combine figure 1 , a degraded condensed tannin modified phenolic resin wood adhesive and a preparation method thereof, comprising the following process steps:

[0040] Step 1, acid-assisted degradation of condensed tannins: mix the solvent and furan or furan derivatives uniformly according to the volume ratio of 2:1-4:1, preferably the volume ratio of solvent and furan or furan derivatives is 3:1; use hydrochloric acid Adjust the pH value of the mixed solution so that the concentration of hydrochloric acid is 0.1mol / L to obtain a condensed tannin degradation solution;

[0041] Step 2, mix the condensed tannins and the tannin degradation liquid evenly, when the concentration of the condensed tannins in the tannin mixed liquid is lower than 10g / L, then the preparation amount of the degraded condensed tannins is too low, the consumption of the degradation liquid is large, and the degraded The cost rises; when the concentration of condensed tannins is higher than 40g / L,...

Embodiment 1

[0060] 1) Mix 600ml of methanol solvent and 200ml of 2-methylfuran evenly, adjust the pH value of the mixed solution with hydrochloric acid, so that the concentration of hydrochloric acid is 0.1mol / L, and obtain a condensed tannin degradation solution;

[0061] 2) Take 240g of acacia tannin and add it to the condensed tannin degradation solution;

[0062] 3) Degrade the Acacia tannin mixture at 50°C for 1.5 hours, then quickly add 12g / L sodium carbonate solution to raise the pH value of the tannin mixture to 8-9;

[0063] 4) Rotating the degraded acacia tannin mixture at normal temperature, and then washing it with water for 3-5 times;

[0064] 5) The acacia marzhan tannin washed with water was vacuum-dried at -60° C. for 24 hours to obtain degraded acacia marzhan tannin.

[0065] 6) Add 60g of phenol, 40g of distilled water, and 40g of NaOH solution (40%) into the flask, stir at 40°C for 10min, and the stirring speed is 300rpm;

[0066] 7) Add 95g of the first batch of form...

Embodiment 2

[0073] 1) Mix 600ml of ethanol solvent and 200ml of furan evenly, adjust the pH value of the mixed solution with hydrochloric acid, so that the concentration of hydrochloric acid is 0.1mol / L, and obtain the condensed tannin degradation solution;

[0074] 2) Take 240g of acacia tannin and add it to the condensed tannin degradation solution;

[0075] 3) Degrade the Acacia tannin mixture at 40°C for 2 hours, then quickly add 12g / L sodium carbonate solution to raise the pH value of the tannin mixture to 8-9;

[0076] 4) Rotating the degraded acacia tannin mixture at normal temperature, and then washing it with water for 3-5 times;

[0077] 5) The acacia marzhan tannin washed with water was vacuum-dried at -60° C. for 24 hours to obtain degraded acacia marzhan tannin.

[0078] 6) Add 60g of phenol, 40g of distilled water, and 40g of NaOH solution (40%) into the flask, stir at 40°C for 10min, and the stirring speed is 300rpm;

[0079] 7) Add 95g of the first batch of formaldehyde ...

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Abstract

The invention discloses a degraded condensed tannin modified phenolic resin wood adhesive and a preparation method thereof. The method comprises the following steps that: furan and derivatives thereofserve as nucleophilic reagents, and degradation and activation of condensed tannin are achieved under an acidic condition; and the degraded and condensed tannin, phenol, a formaldehyde solution, an alkaline solution, polyethyleneimine and distilled water are subjected to stirring and reaction, so that the degraded and condensed tannin modified phenolic resin wood adhesive can be obtained. The furan and derivatives thereof are used as the nucleophilic reagents, the condensed tannin is degraded under the assistance of acid; and therefore, the degradation and activation efficiency of the tanninis high, and the degradation speed of the tannin is high; a resin preparation process is simple; the operability of the method is high; the industrialization feasibility of the method is high; and thetannin modified phenolic resin wood adhesive with high bonding strength and high curing speed can be simply and effectively synthesized.

Description

technical field [0001] The invention belongs to the field of wood adhesive preparation, and specifically relates to a degraded condensed tannin modified phenolic resin wood adhesive and a preparation method thereof. Background technique [0002] my country is the world's largest producer of wood-based panels. In 2018, the total production of wood-based panels in my country reached 299 million cubic meters, accounting for more than 50% of the world's total wood-based panel production. The annual consumption of wood adhesives is more than 20 million tons, of which 90% are Thermosetting "aldehyde" resin adhesive. As an important wood industry adhesive, phenolic resin has the advantages of excellent water resistance, dimensional stability, heat resistance and chemical corrosion resistance compared with other resin adhesives. Outdoor wood-based panels such as recombined wood have shown significant advantages in terms of water resistance and weather resistance, and play an importa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G8/28C08G8/10C09J161/14
CPCC08G8/28C08G8/10C09J161/14
Inventor 李炯炯李建章李晓娜李邝夏常磊
Owner NANJING FORESTRY UNIV
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