Demethylated lignin-based resorcinol-phenol-formaldehyde resin adhesive and preparation method thereof

A technology based on resorcinol and demethylation, applied in adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve the problem of high curing temperature of phenolic resin and high cost of resorcinol , low lignin activity and other problems, to achieve the effect of increasing phenolic hydroxyl content, good economic value, and simple production process

Active Publication Date: 2017-09-19
NANJING UNIV OF TECH
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Problems solved by technology

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a preparation method of a demethylated lignin-based resorcinol-phenol-formaldehyde resin adhesive, which can solve the problem of lignin activity. Low cost, high cost of resorcinol, high curing temperature and long curing time of phenolic resin, etc.

Method used

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  • Demethylated lignin-based resorcinol-phenol-formaldehyde resin adhesive and preparation method thereof

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Effect test

Embodiment 1

[0027] Enzymatic lignin demethylation pretreatment: add 50g of enzymatic lignin to sodium sulfide aqueous solution (dissolve 9g sodium sulfide in 100g water), turn on the stirring paddle to fully dissolve lignin, then heat up to 100°C, add 5g Sulfur, 40g of n-dodecylmercaptan and 2g of sodium borohydride, reacted for 180min, diluted with water after the reaction and adjusted the pH value to 2, centrifuged to obtain demethylated lignin, washed with water until neutral, and dried in a lyophilizer to obtain Pure demethylated lignin with a yield of 90%.

Embodiment 2

[0029] Alkali lignin demethylation pretreatment: Add 50g of alkali lignin into sodium sulfide aqueous solution (5g of sodium sulfide dissolved in 100g of water), turn on the stirring paddle to fully dissolve lignin, then raise the temperature to 90°C, add 3.5g of sulfur , 30g of n-dodecylmercaptan and 3g of sodium borohydride, reacted for 60min, diluted with water after the reaction and adjusted the pH value to 2, centrifuged to obtain demethylated lignin, washed to neutrality and put into a freeze dryer to dry to obtain pure The yield of demethylated lignin was 87%.

Embodiment 3

[0031] Enzymatic lignin demethylation pretreatment: add 50g of enzymatic lignin to sodium sulfide aqueous solution (12.5g of sodium sulfide dissolved in 100g of water), turn on the stirring paddle to fully dissolve lignin, then raise the temperature to 110°C, add 2.5g of sulfur, 50g of n-dodecanethiol and 0.5g of sodium borohydride, react for 120min, add water to dilute and adjust the pH value to 2 after the reaction, centrifuge to obtain demethylated lignin, wash with water until neutral and put it into a freeze dryer Dry in medium to obtain pure demethylated lignin with a yield of 88%.

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Abstract

The invention discloses a demethylated lignin-based resorcinol-phenol-formaldehyde resin adhesive and a preparation method thereof. The preparation method comprises the steps: add lignin into an aqueous solution of sodium sulfide, raising the temperature to be 90 to 110 DEG C, adding sulfur, N-dodecyl mercaptan and sodium borohydride, conducting thermal reaction for 1 to 3 hours, preparing demethylated lignin; dissolving an alkali catalyst in water, raising the temperature to be 60 to 65 DEG C, adding phenol and a formaldehyde aqueous solution, stirring and mixing heating to 85 to 95 DEG C, and reacting for 1 to 1.5 hours; cooling a mixed solution to 60 to 75 DEG C, adding alkaline catalyst aqueous solution, adding the demethylated lignin, and carrying out an initial polycondensation reaction at 60 to 75 DEG C for 1 to 1.5 hours; adding a resorcinol aqueous solution, carrying out the second polycondensation reaction at 60 to 75 DEG C for 1 to 2 hours, and cooling to room temperature to obtain a product. According to the invention, the lignin is demethylated at first to increase the content of phenolic hydroxyl groups in the lignin, and the high active resorcinol is added. The prepared adhesive has low curing temperature, short curing time, good performance and low cost. The replacement rate of demethylated lignin to the resorcinol is 30 to 50%.

Description

technical field [0001] The invention relates to the technical field of adhesive preparation, in particular to a demethylated lignin-based resorcinol-phenol-formaldehyde resin adhesive and a preparation method thereof. Background technique [0002] Structural glulam is a kind of engineered wood formed by curing adhesives, which is one of the forms of modern wood structures. Structural glulam is the basic material for the construction of glulam structures, and plays an important role in wood structure construction. It has the following advantages: (1) Renewable raw materials, green and environmentally friendly; (2) Light in weight, easy to assemble and disassemble and transport; (3) High degree of industrialization and convenient construction; (4) Diversified design and functions; (5) Strong Corrosion resistance, so it can be widely used in wooden structure houses, large space structures and wooden bridges, towers and other building structures. [0003] At present, woodworki...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G8/28C08G8/22C08G8/10C09J161/14C08H7/00
CPCC08G8/10C08G8/22C08G8/28C08H6/00C09J161/14
Inventor 应汉杰蒋忠艳朱晨杰唐成伦甘涛邓彤
Owner NANJING UNIV OF TECH
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