Adhesive for fiber board and preparation method of adhesive

Abstract

The invention discloses an adhesive for a fiber board and a preparation method of the adhesive. The p-tert-butylcatechol is taken as a crosslinking agent to produce dimethylol urea and a urea resin molecule through connection, and a urea resin is synthesized through an acid-neutral-acid-neutral-acid process, so that the molecule of the adhesive is evenly increased, a benzene ring structure is introduced into the molecular structure, the resin curing crosslinking density and rigidity of the urea resin are improved, the capability of capturing free formaldehyde is improved, the bonding strength is very high, and the formaldehyde emission is very low. The adhesive has the advantages that the unconventional p-tert-butylcatechol is used to produce a quinone structure under the actions of a catalyst and an oxidizing agent, the acid-neutral-acid-neutral-acid process is used to gradually increase the molecular chain of the urea resin and finally form a network structure, the formed resin is low in molecular weight and high in reaction activity, the basic procedure is close to the conventional process, the process is simple, the operation is simple, and the existing equipment is not transformed.

Description

technical field [0001] The invention relates to an adhesive and a preparation method thereof, in particular to a urea-formaldehyde resin adhesive used for preparing fiberboards and a preparation method thereof. Background technique [0002] With the improvement of people's living standards and the continuous and stable development of construction, decoration, packaging and other industries, the output of fiberboard in my country has grown rapidly. In 2014, the total output of fiberboard in my country was 69 million m3, a year-on-year increase of 6.4%, of which the use of urea-formaldehyde resin and its modified products accounted for more than 90% of the total output. Urea-formaldehyde resin adhesives are widely used in the fiberboard industry due to their incomparable advantages over other resins, such as sufficient raw materials, low price, good water solubility, and light color of the adhesive layer. But urea-formaldehyde resin also has obvious disadvantages. In addition...

AI Technical Summary

Problems solved by technology

For example: 1) Although the use of low molar ratio modified urea-formaldehyde resin adhesive can effectively reduce the formaldehyde emission of the product, the bonding strength of the product is often reduced, which cannot meet the requirements of use; and it can lead to prolonged curing time and reduced production efficiency; 2) in urea-formaldehyde Adding a formaldehyde scavenger to the resin adhesive can effectively reduce the release of free formaldehyde, but at the same time reduce the bonding strength of the product; at the same time, the price of the general formaldehyde scavenger is much higher than that of the urea-formaldehyde resin adhesive, and its addition increases the product cost and reduces product competition. 3) After-treatment of wood-based panels, these post-treatment methods not only make the fiberboard manufacturing process complicated, but also require a huge investment in post-treatment equipment, and the production cost is significantly increased; 4) Using other environmentally friendly adhesives, such as isocyanate adhesives, leads to man-made The cost of board production increases and the difficulty of the production process increases, which is unacceptable to both enterprises and users; the use of ordinary protein adhesives to prepare fiberboards has low bonding strength, high water expansion rate, easy to mold, and poor sizing performance

In summary, although the above measures can effectively reduce the release of free formaldehyde in the preparation of wood-based panels, they also bring about other problems such as reduced bonding strength and high production costs, which cannot be popularized.

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