The output of urea resins increased markedly in 1936 and 1937. Statistics for those years cannot be published without disclosing operations of individual firms. It may be stated, however, that the increase in both years over the previous year was considerably greater than for any earlier period. Most of the production was used in molded articles although appreciable quantities were consumed in laminated articles, in surface coatings, in the impregnation of fabric, and in adhesives. There were 10 domestic makers of these resins in 1937. Domestic production and sales of urea resins are shown in table 8. TABLE 8.—_Urea resins: United States production and sales, 1933-37_ --------+------------+------------------------------------ | | Sales Year | Production +-----------+------------+----------- | | Quantity | Value | Unit value --------+------------+-----------+------------+----------- | _Pounds_ | _Pounds_ | | 1933 | 3,234,356 | 2,977,791 | $1,422,671 | $0.48 1934 | 3,470,916 | 3,115,608 | 1,290,802 | .41 1935 | 4,202,536 | 4,005,083 | 1,828,565 | .46 1936-37 | ([1]) | ([1]) | ([1]) | [1] Not publishable; figures would reveal operations of individual firms. Source: Dyes and Other Synthetic Organic Chemicals in the United States, U. S. Tariff Commission. United States imports and exports. Resins obtained from urea and thiourea, if imported, would probably be classified under paragraph 11 of the Tariff Act of 1930. The present rate of duty under this classification is 4 cents per pound and 30 percent ad valorem. There has been no importation of these resins. This is due principally to the international licensing arrangements which usually include the allocation of markets. Exports are not shown separately in official statistics. 6. ACRYLATE RESINS A new development of widespread importance in the synthetic resin industry is the commercial production of the polymers of certain derivatives of acrylic acid. The commercial exploitation of the acrylates is another example of the belated realization of the value of substances known for many years. Acrylic acid has been known for about a hundred years, and the polymer of methyl acrylate was first described in 1880. It was not until 1927, however, that a suitable method for their commercial production was developed. The study of the many derivatives of acrylic and methacrylic acids leads to the conclusion that those of greatest practical application in the resin field are the lower esters, such as methyl and ethyl, polymerized separately or together.