About 1929 the first successful straight urea product was perfected in the United States. It was found that a filler, such as highly refined alpha cellulose, minimized the stresses. The filler (as much as 30 to 40 percent is usually incorporated), destroys the transparency but permits the manufacture of translucent articles in a wide range of color. Many of the colors possible with the urea resins, particularly the light shades, cannot at present be obtained in molded tar-acid resins. An interesting fact concerning these resins is that they are produced indirectly from four gases: Ammonia, carbon dioxide, hydrogen, and carbon monoxide. Ammonia and carbon dioxide react to form urea, and hydrogen and carbon monoxide yield methyl alcohol which is converted to formaldehyde. Description and uses. The urea resins are outstanding largely because of their brilliancy and depth of color, properties not readily obtained in other thermosetting resins. Being odorless and tasteless and completely resistant to oils and greases, they are adapted to use in the manufacture of cosmetic containers. Concentrated acids and alkalies attack the resin. The electrical properties of the urea resins compare favorably with those of the tar-acid resins. They have a lower power factor at high-frequencies than the tar-acid resins, and are replacing, to some extent, established materials in heavy duty electrical equipment where “tracking” causes trouble. Molded articles made from urea resins are resilient but not unbreakable. [Illustration: THERMOSTAT CASE OF MOLDED UREA RESIN. Source: Plaskon Company, Inc., 2112 Sylvan Avenue, Toledo, Ohio.] [Illustration: SCALES CASE OF MOLDED UREA RESIN. Source: Plaskon Company, Inc., 2112 Sylvan Avenue, Toledo, Ohio.] The important uses of the urea resins are dictated by their pleasing color and appearance. In 1935 the largest outlets were in buttons and buckles, in bottle closures, and in such premium items as biscuit cutters and cereal bowls distributed by a large food manufacturer. Tableware, bathroom fixtures, all sorts of containers and closures, housings for radios, clocks, scales, and other machines for retail stores, and light-colored wall plates and switches, knobs, handles, and trim on dash panels of automobiles, and handles and trimming on gas and electric ranges were among the widespread applications of the urea resins. In 1938 probably the fastest growing outlet for urea resins is in lighting equipment. Use in packaging, in closures, and in housings, is also increasing. Tableware, the principal outlet for a number of years, is declining markedly.