The patent situation may militate against exports as well as imports. Where a company owns foreign patents it may set up a company to exploit them abroad, or it may license their use by others. Again, mutual interest may dictate an exchange (by cross-licensing) of certain patents. International licensing of patents is usually accompanied by divisions of international markets through formal or informal understanding. Such agreements may outlive the life of the patents, especially if bolstered with financial connections. But unless the original producers continue to dominate their respective markets, any agreements between them are likely to diminish in importance, because after the patents expire new competitors would have a free hand in foreign as well as domestic markets. The original United States producer of tar-acid resins set up or licensed companies to manufacture in a number of foreign countries. The urea-formaldehyde process was developed in Europe and the first American producer was a licensee of a British corporation. Similar arrangements exist with regard to most of the other resins. The United States tariff on resins and resin products. _Synthetic resins._—Imports of tar-acid, alkyd, coumarone and indene, styrol, adipic, and aniline resins are dutiable under the provisions of paragraph 28 of the Tariff Act of 1930, which reads in part: “synthetic phenolic resin and all resinlike products prepared from phenol, cresol, phthalic anhydride, coumarone, indene, or from any other article or material provided for in paragraph 27 [coal-tar intermediates] or [paragraph] 1651 [coal-tar crudes], all these products whether in a solid, semisolid, or liquid condition; ... 45 per centum ad valorem [based on American selling price[7] or United States value[8]] and 7 cents per pound.” Where these resins are produced in the United States, imports are “competitive” and the dutiable value is based upon American selling price. If the American selling price is higher than the foreign value, the effect of this method of valuation is to increase the duty to which imports are subject. The duty of 45 per cent ad valorem and 7 cents per pound was equivalent to 54 per cent ad valorem on the American selling price of the small imports of coal-tar resins in 1937. If it could calculated upon foreign value it would be much higher. Synthetic resins of non-coal-tar origin, except vinyl resins, are dutiable under paragraph 11, which reads “synthetic gums and resins not specially provided for, 4 cents per pound and 30 per centum ad valorem” on foreign value. This rate was the equivalent of 48 per cent ad valorem upon the small amount of imports in 1937. The most important resins included are the urea and acrylate resins.