Method for preparing aldehyde-free veneer boards by biological oil starch adhesives

Abstract

The invention relates to a method for preparing aldehyde-free veneer boards by biological oil starch adhesives and belongs to the field of artificial board production. The method comprises the steps of biological oil starch adhesive preparation: vacuum filtration and reduced pressure distillation method are adopted for carrying out pretreatment on biological oil; wild cassava starch is added into water, starch emulsion and concentrated hydrochloric acid are prepared, after the temperature is raised, oxidants of persulfate are then added, and acidolysis oxidized starch emulsion is prepared through reaction; the biological oil is added into the emulsion, polyving akohol solution is added, then, alkali liquor and oxalic acid are repeatedly and alternately added; and then, borax is added until the viscosity reaches the requirements, and main agents of biological oil starch adhesives are obtained; and aldehyde-free veneer board preparation: single boards are dried and are subjected to adhesive coating at two sides by adopting the prepared adhesives, the single board blank assembly is carried out according to the odd layer principle and in a mode that the fiber directions of adjacent single boards are mutually vertical, the veneer boards are pressed and manufactured under the hot pressing curve, and the aldehyde-free veneer boards are obtained. The preparation process is simple, and the intensity of the prepared veneer boards reaches the requirements of II type veneer boards.

Description

technical field [0001] The invention belongs to the field of wood-based panel production, and relates to a method for preparing formaldehyde-free plywood, in particular to a method for preparing formaldehyde-free plywood from biological oil starch adhesive. Background technique [0002] The adhesive used in plywood is an important factor in determining the quality, cost and environmental performance of plywood. At present, traditional three-aldehyde adhesives (urea-formaldehyde resin adhesives, phenolic resin adhesives, and melamine resin adhesives) are mostly used in the preparation of plywood, of which urea-formaldehyde resin adhesives are mainly used, but the adhesives will release formaldehyde, which is harmful to human health; Adhesive raw materials are heavily dependent on fossil resources and are not renewable. With the improvement of consumers' awareness of environmental protection and the stricter restrictions on harmful substances in relevant laws and regulations,...

AI Technical Summary

Problems solved by technology

CN102152345A provides a method for producing formaldehyde-free plywood with vegetable protein adhesives. The bonding strength and water resistance of plywood prepared by this method can meet the technical index requirements of urea-formaldehyde resins, but various auxiliary materials need to be added in the preparation process of vegetable protein adhesives. In order to meet the requirements, the plant protein separation process is relatively complicated

CN101323762A provides a kind of starch and polyvinyl alcohol (PVA) blending, adding complexing agent and crosslinking agent worth starch-based adhesive main agent, using polyisocyanate as curing agent, the prepared adhesive can replace urea-formaldehyde resin, and can be used in Preparation of formaldehyde-free plywood, but polyisocyanate is highly volatile, which pollutes the production environment, and the amount of polyisocyanate added is too high, resulting in high cost of plywood

CN101157833A has invented cornstarch as the main raw material to prepare the main agent of starch-based water-based polymer-isocyanate adhesive, adding curing agent polyisocyanate to obtain a formaldehyde-free starch-based adhesive, which can be used for the preparation of formaldehyde-free plywood, but this The main raw material of the adhesive is edible cornstarch, which is likely to cause a shortage of resources, and the large-scale promotion is limited

CN101857787A provides a method for modifying composite modified starch emulsion by using synthetic bio-oil phenolic resin to prepare starch-based adhesive. This adhesive can be used for the preparation of formaldehyde-free plywood, but the ratio of bio-oil phenolic resin in the adhesive is relatively high. And there is free phenol in the adhesive, which has certain pollution to the environment

CN102010678A provides a bio-oil-phenol-starch resin prepared by polymerizing modified starch, phenol and bio-oil, and then adding the prepared starch-based cross-linking agent to obtain a formaldehyde-free adhesive, which contains certain A large amount of phenol will pollute the environment; the price of oxidizing agent added in the process of starch denaturation is high, resulting in high cost of adhesive

CN101805568A provides a method of using starch and bio-oil as the main raw materials, performing compound denaturation on starch and then reacting with refined bio-oil, then adding a certain auxiliary agent, and esterifying it with oxalic acid to obtain the main agent of the adhesive, and finally adding a curing agent The adhesive obtained can be used for the preparation of formaldehyde-free plywood, but the cost of the adhesive is high and the preparation process is relatively complicated, which is not conducive to popularization and application

Images