Formaldehyde-free soybean protein based adhesive and preparation method thereof

Abstract

The invention discloses a formaldehyde-free soybean protein based adhesive and a preparation method thereof. The adhesive is prepared from soybean meal, bromelain, bean chitinase, dispersion medium water, sodium periodate, diethylenetriamine, glutaraldehyde diglycidyl ether and a curing agent. According to the formaldehyde-free soybean protein based adhesive obtained with the preparation method, soybean meal molecules are degraded, modified and recombined to form a prepolymer, proteins stretch sufficiently, molecular active groups are increased obviously, reactivity, solubility, water-retention and toughness are improved, and after addition of an elastomer-based curing agent, the prepared adhesive has high flexibility, water-resistant adhesion and stability; the requirement of an artificial board adhesive for water resistance can be met, cost of the adhesive is reduced due to reduction of use quantity of a crosslinking agent, and practicability of the protein based adhesive is guaranteed.

Description

technical field [0001] The invention relates to the technical field of wood-based panel adhesives, in particular to a formaldehyde-free soybean protein-based adhesive and a preparation method thereof. Background technique [0002] my country is short of precious wood resources, but there are abundant plantation forest resources. The wood-based panels prepared by using plantation fast-growing wood and agricultural and forestry processing residues through adhesives are the main raw materials for furniture floors and interior decoration in the living environment. In 2016, The total output of wood-based panels in my country is 320 million cubic meters, accounting for about 50% of the world's total output. Based on the average production of 9 cubic meters of wood-based panels per ton of adhesive, the consumption of wood adhesives in my country in 2015 was about 40 million tons (solid content 50%), of which urea-formaldehyde resin and its modified products accounted for 20% of the ...

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Problems solved by technology

However, urea-formaldehyde resin also has obvious disadvantages, such as poor aging resistance, poor water resistance, and cannot be used to prepare wood-based panels for outdoor use.

[0003] The use of vegetable protein adhesives to prepare wood-based panels can solve the problem of free formaldehyde release from wood-based panels, but there are problems such as poor water resistance and bonding performance, and unstable production. This is because the raw materials used to prepare protein adhesives such as soybean meal and cotton meal 1. Due to poor protein solubility, large particles, and large molecular weight of peanut meal, the modification method of adding an external cross-linking agent cannot modify the matrix, resulting in uneven distribution of the cross-linked structure of the protein adhesive and poor toughness. A large number of weak interface layers and poor water retention capacity. Although the average strength meets the requirements, the bonding quality of different areas of wood-based panels varies greatly, the bonding strength is unstable, and the production efficiency is low.

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