Urea-formaldehyde resin low cost, light color, high hardness, oil resistance, mildew resistance, good insulation and temperature resistance, but weathering and water resistance is poor. It is one of the early thermosetting resins developed. 1924, the United Kingdom of Ammonia production company, 1928 the sale of products, 30 generation of medium-term output of 1000 tons, the 80 generation of the world's annual output has exceeded 1.5Mt.
The number of urea-formaldehyde resins used in plastic products accounted for only about 10%% of total production. Urea-formaldehyde resins made in the case of lower molar ratios of formaldehyde and urea with fillers (pulp, wood powder), pigments, lubricants, curing agent, stabilizer (6 sub-methyl amine, ammonium carbonate), plasticizer (urea or thiourea) and other components of mixing, and then through drying, crushing, ball mill, sieving, that is, urea-formaldehyde pressure molding powder. To suppress the temperature 140, pressure 25~35MPa of urea-formaldehyde plastics, the suppression time varies according to the thickness of the products, usually 10~60min. Plastic products are mainly electrical lighting equipment and telephone parts and so on.
Urea-formaldehyde resin is generally water-soluble resin, more easily cured, cured resin, non-toxic, colorless, good light resistance, long-term use does not discoloration, hot molding does not change color, can be added to various coloring agents to prepare a variety of brightly colored products.
Urea-formaldehyde resin hardness, scratch resistance, weak acid base and grease and other media, cheap, with a certain toughness, but it is easy to absorb water, and thus resistance to water and electrical performance is poor, heat resistance is not high.