Urea resin and production thereof

Abstract

A urea resin and its production are disclosed. The procedure is carried out by taking low-mol ratio methyl aldehyde and urea as raw materials, adding urea into methyl aldehyde by 4 times, activating methyl aldehyde at 50+-5 degrees C for 15-25mins before adding urea for first time, and adding into ammonia water to have rear-treatment after adding urea for fourth time to obtain final product. It is simple and cheap, has no any modifier and dewatering.

Description

technical field [0001] The invention relates to a urea-formaldehyde resin and a preparation method thereof, in particular to a urea-formaldehyde resin for wood-based panels and a preparation method thereof. Background technique [0002] With the continuous improvement of people's living standards, decoration and purchase of new furniture have become common things in people's lives. Various types of wood-based panels are often used in decoration and furniture manufacturing, such as plywood, blockboard, medium-density fiberboard, particle board, etc., and most of these wood-based panels use formaldehyde-based adhesives, mainly urea-formaldehyde resin adhesives, which generally have the problem of formaldehyde release. , often become the chief culprit of formaldehyde pollution in indoor air. [0003] Formaldehyde is a highly toxic substance, and it ranks second on the list of priority control of toxic chemicals in my country. Formaldehyde is irritating to the eyes, mucous mem...

AI Technical Summary

Problems solved by technology

For example, 1) Although the use of a low molar ratio modified urea-formaldehyde resin adhesive can effectively reduce the formaldehyde emission of wood-based panel products, the bonding strength of the product is often reduced, which cannot meet the requirements; and the curing time of the adhesive is prolonged, and the production efficiency is reduced; 2) Using other environmentally-friendly adhesives, such as isocyanate adhesives, often increases the production cost of wood-based panels, which is difficult for enterprises and users to accept; 3) Adding formaldehyde scavenger to the urea-formaldehyde resin adhesive for wood-based panels can effectively reduce the free of wood-based panels. formaldehyde emission, but often reduce the bonding strength of wood-based panels at the same time; in addition, the price of general formaldehyde capture agents is often much higher than that of urea-formaldehyde resin adhesives, and its addition increases product costs and reduces product competitiveness; 4) for wood-based panels Carry out aftertreatment, disclose a kind of manufacturing process of E1 / EO grade environment-friendly wood-based panel in the invention patent application of publication number CN1526528A adopt ammonia gas vacuum method, disclose a kind of reducing man-made in the utility model patent of publication number CN2394770Y Although these measures can effectively reduce the release of free formaldehyde from wood-based panels, the investment in post-processing equipment is often large.