Description
Urea-formaldehyde resin (UF), also known as urea-formaldehyde resin, is the polycondensation of urea and formaldehyde under the action of a catalyst (alkaline or acidic catalyst) to form an initial urea-formaldehyde resin, and then forms an insoluble and infusible final phase under the action of a curing agent or additive. Thermosetting resin. [1] Cured urea-formaldehyde resin is lighter in color than phenolic resin, translucent, resistant to weak acids and weak alkali, has good insulation properties, excellent wear resistance, and is cheap. It is the most commonly used variety among adhesives, especially in In the manufacturing of various artificial boards in the wood processing industry, urea-formaldehyde resin and its modified products account for about 90% of the total adhesive usage. However, urea-formaldehyde resin is easy to decompose when exposed to strong acids and alkalis. It has poor weather resistance, poor initial viscosity, large shrinkage, brittleness, water resistance, and easy aging. Artificial boards produced with urea-formaldehyde resin release formaldehyde during the manufacturing and use process. problem, so it must be modified
1. Used as cross-linking agent for emulsion adhesives. It can react and cross-link with one OH in polyvinyl acetate emulsion to improve water resistance and heat resistance. The -CH2OH and NH2 of the urea-formaldehyde resin molecules can be condensed and cross-linked to a certain extent with the -COOH in the acrylic modified emulsion molecules, reducing the hydrophilic groups, improving the water resistance, and enhancing the anti-freezing ability.
2. It can be used for products that do not require high water resistance and dielectric properties, such as power strips, switches, machine handles, instrument casings, knobs, daily necessities, decorations, mahjong tiles, toilet lids, and can also be used in the manufacture of some tableware. .
3. Urea-formaldehyde resin is the most widely used type of adhesive. Especially in the manufacturing of various artificial boards in the wood processing industry, urea-formaldehyde resin and its modified products account for about 90% of the total adhesive usage.
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