Preparation method and application method of formaldehyde-free protein-based wood adhesive

Abstract

The invention discloses a preparation method a formaldehyde-free protein-based wood adhesive. According to the invention, fresh plant stems and leaves are added into water, and are crushed and press-filtrated, such that a juice is obtained; soybean meal and separated animal protein or separated vegetable protein are sieved by using a sieve of 60 to 300 meshes; the meshed materials are stirred with water according to a ratio of 0-1:1-0:5-15, until a crude protein content of the mixture is 7 to 20%; the mixture is placed in a reactor, and is stirred for 30min to 5h under a temperature of 45 to 65 DEG C and a pH value of 8.5 to 13.5, such that the mixture is subject to a reaction; when the temperature is reduced to 35 to 45 DEG C, the fresh plant stem and leaf juice obtained through the press-filtration step is added to the mixture of protein and water while stirring, wherein the juice takes 0.1% to 50% of the weight of the mixture; the content of adhesive mass crude protein is controlled, that when the adhesive is used in a plywood, the content is 11 to 13%, and when the adhesive is used in a fiber board, the content is 5 to 7%; the pH value of the material is regulated to 7.5 to 10.5, and the material is stirred for 15 to 45min; 0.00 to 0.50% of a preservative is added, and polyphenol is blended. The adhesive provided by the invention is not polluted by free formaldehyde, volatile phenols, isocyanate or synthetic resin. A conflict of protein denaturation and hydrolysis can be regulated by using a heat denaturation technology. When denaturation is finished, the reaction temperature and the pH value can be reduced instantly. With the invention, the produced artificial plates satisfy an international standard of II grade plates. After the plates are boiled for 4 hours by boiled water with a temperature of 100 DEG C, adhesive failure is not occurred.

Description

technical field [0001] The invention belongs to the technical field of wood bonding, and in particular relates to a preparation method and a use method of a wood adhesive. technical background [0002] In recent years, the development of green and environmentally friendly wood adhesives using biomass as the basic raw material has received more attention. Protein-based wood adhesives are the most promising type. However, compared with trialdehyde gum, the most urgent problems to be solved for bean gum are the competition between raw materials and food and feed; the product has high consistency and low viscosity; and its water resistance is relatively weak. In terms of protein glue research, some meaningful work has been done on expanding raw protein resources, improving soybean protein denaturation technology, and improving the bonding strength of protein glue. For example, China’s authorized patent CN10049149C promotes applicable protein raw materials to single-cell protei...

AI Technical Summary

Problems solved by technology

However, compared with trialdehyde gum, the most urgent problem to be solved for bean gum is that there is a competitive relationship between raw materials and food and feed; the product has a large consistency and low viscosity; water resistance is relatively weak, etc.