Overview of button raw material urea formaldehyde resin

September 26, 2023

Urea formaldehyde resin

Urea-formaldehyde resins

Product name Beetle. Also known as urea formaldehyde resin, referred to as UF, with an average molecular weight of about 10,000. Urea and 37% formaldehyde aqueous solution can be condensed under the acid or alkali catalysis to obtain linear urea-formaldehyde oligomers. The industry uses alkali as the catalyst and reacts at about 95Â° C. The formaldehyde/urea molar ratio is 1.5-2.0 to ensure that the resin can be cured. . The first step of the reaction produces mono- and dihydroxymethyl ureas. The hydroxymethyl group is then further condensed with the amino group to give a soluble resin which, if catalyzed by an acid, can easily lead to gelation. The product must be stored under neutral conditions. Linear urea formaldehyde resins cure at room temperature with ammonium chloride as the curing agent. Molding powder is heat-cured at 130-160Â°C. Accelerators such as zinc sulfate, trimethyl phosphate, and diethyl oxalate accelerate the curing process. Urea-formaldehyde resin is mainly used for manufacturing molded plastics, manufacturing daily life products and electrical parts, as well as sheet adhesives, paper and fabric pastes, plywood, and architectural decorative boards. Because of its light color and easy coloring, the products are often colorful and magnificent.

Urea-formaldehyde resin has low cost, light color, high hardness, oil resistance, mildew resistance, good insulation and temperature resistance, but poor weather resistance and water resistance. It is one of the earlier developed thermosetting resins. In 1924, the British cyanomethine company developed and sold products in 1928. The output in the mid 30's reached 1,000 tons. In the 1980s, the world's annual output exceeded 1.5 Mt.

The number of urea-formaldehyde resins used to make plastic products is only about 10% of the total production. Urea-formaldehyde resin prepared with a relatively low molar ratio of formaldehyde to urea, with fillers (pulp, wood flour), colorants, lubricants, curing agents, stabilizers (hexamethylene tetramine, ammonium carbonate), The plasticizer (urea or thiourea) and other components are mixed and then dried, crushed, ball milled, and sieved to obtain urea-formaldehyde-compressed powder. The temperature at which the urea-formaldehyde plastic is suppressed is 140-150Â° C. and the pressure is 25-35 MPa. The pressing time varies depending on the thickness of the product, and is generally 10 to 60 minutes. Plastic products are mainly electrical lighting equipment and telephone parts.

Urea-formaldehyde resin is generally a water-soluble resin and is relatively easy to cure. The cured resin is non-toxic, colorless, and has good light resistance. It does not change color during long-term use, and it does not change color during thermoforming. Various colorants can be added to make various bright colors. Products.

Urea-formaldehyde resins are hard, scratch-resistant, resistant to weak acids, weak bases, and oils and other media. They are inexpensive and have a certain degree of toughness. However, they are easy to absorb water, and thus have poor water resistance and electrical properties, and their heat resistance is not high.