Preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive

An environmentally friendly urea-formaldehyde resin and lignin technology, applied in adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve problems such as polluting the indoor environment and threatening human health, and achieve improved environmental protection levels. Market application prospects, the effect of mild reaction conditions

Active Publication Date: 2021-04-09
CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, urea-formaldehyde resin will release formaldehyde during use, pollute the indoor environment, and threaten human health

Method used

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  • Preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive
  • Preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive
  • Preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive

Examples

Experimental program
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Effect test

Embodiment 1

[0042] A kind of preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive, comprises the following steps:

[0043] (1) Take sodium lignosulfonate 200g, dissolve it in 300g water, and carry out mechanical stirring to it, configure 40wt.% lignosulfonate aqueous solution, wherein, the ash content of sodium lignosulfonate is 20 %.

[0044] (2) Aspergillus laccase produced by aspergillus with an enzyme activity of 10000U / g is added in an amount of 50U / g to add 1g of laccase to lignin aqueous solution, and 2g of syringic acid methyl is added by 1% of the quality of sodium lignosulfonate esters as mediators. Adjust the pH value of the lignin aqueous solution added with laccase and mediator to 5.0 with formic acid, and react for 4 hours at a water bath temperature of 50° C., stirring continuously during this period. After the reaction is completed, a depolymerized lignin solution is obtained.

[0045] (3) Use sodium hydroxide to adjust the pH value...

Embodiment 2

[0061] A kind of preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive, comprises the following steps:

[0062] (1) Take by weighing sodium lignosulfonate 200g, be dissolved in 600g water, and it is mechanically stirred, configure the lignosulfonate aqueous solution of 25wt.%, wherein, the ash content of sodium lignosulfonate is 20 %.

[0063] (2) The laccase produced by white rot fungus with an enzyme activity of 5000U / g is added to the lignin aqueous solution in an amount of 50U / g, and 2g of laccase is added according to 1% of the quality of sodium lignosulfonate. Lansu as a mediator. Adjust the pH value of the lignin aqueous solution added with laccase and mediator to 4.5 with formic acid, and react for 2 hours at a water bath temperature of 45° C., stirring continuously during this period. After the reaction is completed, a depolymerized lignin solution is obtained.

[0064] (3) Use sodium hydroxide to adjust the pH value of the depo...

Embodiment 3

[0069] A kind of preparation method of lignin modified environment-friendly urea-formaldehyde resin adhesive, comprises the following steps:

[0070] (1) Take by weighing sodium lignosulfonate 200g, be dissolved in 800g water, and it is mechanically stirred, configure the lignosulfonate aqueous solution of 20wt.%, wherein, the ash content of sodium lignosulfonate is 20 %.

[0071] (2) Add 2 g of laccase to the lignin aqueous solution by adding 40 U / g of laccase for textile with an enzyme activity of 4000 U / g, and add 2 g of phenothiazine according to 1% of the quality of sodium lignosulfonate as a mediator. Adjust the pH value of the lignin aqueous solution added with laccase and mediator to 4.7 with formic acid, and react for 3 hours at a water bath temperature of 55° C., stirring continuously during the period, and depolymerized lignin solution is obtained after the reaction is completed.

[0072](3) Use sodium hydroxide to adjust the pH value of the depolymerized lignin s...

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Abstract

The invention discloses a preparation method of a lignin modified environment-friendly urea-formaldehyde resin adhesive. The method comprises the following steps: (1) dissolving lignosulfonate to obtain a lignin solution, and adding a biological enzyme and a mediator into the lignin solution to jointly depolymerize lignin to obtain a depolymerized lignin solution; (2) adjusting the depolymerized lignin solution to be weakly alkaline, and adding a silane coupling agent for grafting reaction to obtain a lignin modified solution; and (3) adding formaldehyde and urea into the lignin modified solution to react so as to obtain the lignin modified environment-friendly urea-formaldehyde resin adhesive. According to the invention, the preparation method of the lignin-modified environment-friendly urea-formaldehyde resin adhesive is mild in reaction condition, environmentally friendly and free of pollutants, graft modification is conducted on ash, copolymerization of lignin, ash particles and urea-formaldehyde resin is achieved, the usage amount of formaldehyde in the urea-formaldehyde resin synthesis process is reduced, and the problems of high formaldehyde release amount, poor environmental friendliness of the urea-formaldehyde resin adhesive and the like are solved.

Description

technical field [0001] The invention belongs to the field of adhesives, in particular to a method for preparing a urea-formaldehyde resin adhesive. Background technique [0002] Lignin is an amorphous polymer composed of phenylpropane units connected by carbon-carbon bonds and ether bonds, and it is also a biomass resource second only to cellulose in nature. Globally, more than 25 million tons of lignin are produced annually by papermaking alone. Although lignin contains a large number of active groups such as phenolic hydroxyl groups, alcoholic hydroxyl groups, carbonyl groups, and carboxyl groups, due to its large molecular weight and high degree of polymerization, there are very few active groups exposed in lignin molecules, resulting in low lignin reactivity and industrialization. Difficult to apply. In addition, the cost of activating lignin by chemical modification and other methods is high, the pollution is large, and the yield is low. The search for a simple, low-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J161/32C08G12/40
CPCC09J161/32C08G12/40
Inventor 刘明杨守禄吴义强卿彦罗莎李贤军李新功李天华田翠花徐康
Owner CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY
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