------+-------------+--------------------------------------- | | Sales Year | Production +------------+-------------+------------ | | Quantity | Value | Unit value ------+-------------+------------+-------------+------------ | _Pounds_ | _Pounds_ | | 1934 | 4,968,445 | 4,793,658 | $2,099,035 | $0.44 1935 | 5,566,621 | 5,454,490 | 2,205,879 | .40 1936 | 6,111,632 | 6,013,855 | 2,476,619 | .41 1937 | 5,459,654 | 5,335,746 | 2,180,620 | .41 ------+-------------+------------+-------------+------------ Source: Dyes and Other Synthetic Organic Chemicals in the United States, U. S. Tariff Commission. Imports and exports. The licensing agreements, as outlined above, provide for the allocation of markets for cast phenolic resins. Because of this arrangement there are little or no imports and exports of this material. TAR-ACID RESINS FOR LAMINATING By laminating is meant the impregnation of sheets of paper, fiber, or cloth with a solution of synthetic resin and the building up of these layers into sheets of reinforced synthetic resin of various thicknesses. When a tar-acid resin is used the paper or cloth is immersed in or coated with a solution of the B-stage resin, dried, and layers of the material are compressed and consolidated, under heat and pressure to form sheets, rods, tubes, blocks, and other forms, in the infusible C-stage. The coating of sheets of paper with solutions of natural resin and the compacting of these sheets by heat and pressure is an old practice, especially for electrical uses. Shellac and copal have been widely used and yield a laminated board of good electrical and mechanical properties when used at temperatures under 70° C. Above 70° C. the resin softens and the desirable properties are lost. Since temperatures above 70° C. are not uncommon in electrical equipment, the limitations of these natural resins in this use can readily be seen. The use of tar-acid resins to impregnate insulation material removes the temperature limitation and otherwise improves the product; insulators so made are widely used in all sorts of electrical and radio equipment. Uses of tar-acid resin laminated products. Laminated sheets of tar-acid resin are made with paper, canvas, duck, linen, pulpboard, vulcanized fiber, plywood, and other materials. Paper is the material generally used for electrical insulation, although cloth is sometimes used when greater strength is needed. Canvas is used where maximum strength is required, as in gears for automobiles and industrial machinery. Impregnated linen is adapted to punched parts and small gears.