Lignin-phenol-urea-formaldehyde co-condensation resin adhesive and preparation method

Abstract

The invention provides a lignin-phenol-urea-formaldehyde polycondensated resin adhesive and a preparation method. The preparation method is carried out by means of controlling addition and condensation reaction step by step, and comprises the following steps: firstly, reacting first-batch urea with a first-batch formaldehyde solution in an alkaline medium to obtain a first-stage reaction product; reacting the first-stage reaction product with lignin in an alkaline medium to obtain a second-stage reaction product; reacting the second-stage reaction product with phenol and a second-batch formaldehyde solution in the alkaline medium to obtain a third-stage reaction product; reacting the third-stage reaction product with a third-batch formaldehyde solution in the alkaline medium to obtain a fourth-stage reaction product; and reacting the fourth-stage reaction product with a second-batch urea in the alkaline medium to obtain the adhesive. The strength of the prepared adhesive can meet the strength requirement on national I-class plates, the emission amount of the formaldehyde meets the E0-level limit requirement, the addition ratio of the lignin is high, the preparation method is low, and thus great economic and social significance can be achieved.

Description

technical field

[0001] The invention relates to the field of wood adhesive preparation, in particular to a lignin-phenol-urea-formaldehyde co-condensation environmentally friendly resin adhesive and a preparation method thereof. Background technique

[0002] The world produces about 150-180 million tons of industrial lignin every year, and most of these industrial lignins are used as heat sources, and less than 1% are reused as useful chemical products, which not only causes environmental pollution, but also damages valuable resources. a great waste. For the pulp and paper industry and related biorefining enterprises, the unreasonable use of lignin by-products will lead to a great waste of the remaining production capacity of the enterprise, affecting the overall efficiency and sustainable development of the enterprise. As a phenolic compound with a huge content in nature, lignin is regarded as a potential substitute for petrochemical resources. A large number of researcher...

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