The monomer (unpolymerized methyl methacrylate) may be used to impregnate wood, cloth, wallboard, cork, paper, electrical coils, tile, or stone, and then polymerized to form the resin. Paper and cloth so treated have many uses, such as in the electrical and food-packaging industries. Laminated sheets find wide possibilities for use in the aircraft field, and for lamp shades. Wood may be impregnated with as much as 60 percent of the monomer. Solutions of these resins in organic solvents, such as ethylene dichloride, ethyl acetate, and toluol, are used in surface coatings, undercoats on difficult adhesion jobs, to impregnate paper and textiles, and in insulation. These coating solutions are marketed in the United States under the trade name Acryloids and in Europe under the trade names, Borron, Plexigum, and Acronol. They may be brushed, sprayed, dipped, and baked. Baking is recommended to give a higher gloss, better adhesion, and a harder film. The dried film has an elasticity of 1,000 percent at ordinary room temperature and the light transmission of clear films is intermediate between ordinary window glass and quartz. Acrysol is an adhesive consisting of a dispersion of the resin in water and is recommended for use where adhesion is difficult, as on rubber or rubberized surfaces. Production in the United States. Commercial production of acrylate resins in the United States was started in 1931 by Rohm and Haas, Philadelphia, Pa., under United States Patents Nos. 1,388,016 of August 16, 1921, and 1,829,208 of October 27, 1931. Commercial production of methyl methacrylate resins was started in 1937 by E. I. du Pont de Nemours & Co. This development is under United States Patent No. 1,980,483, issued in 1934. The liquid monomer is produced at Belle, W. Va., and shipped to Arlington, N. J., where it is polymerized by heat to the solid resin. The output of acrylate resins was hardly more than experimental in 1935 but increased somewhat in 1936 and very appreciably in 1937. Although statistics of production are not publishable, it can be stated that in 1937 the output approached that of other synthetic resins made in commercial quantities. The properties of these resins indicate very large commercial production in the near future. Prices of the several types are still high as compared with other resins but should eventually be somewhat lower than those of cellulose acetate and nitrocellulose plastics and slightly higher than those of cast phenolic resins. Imports into and exports from the United States. There have been no recorded imports of acrylate resins. The two domestic producers have agreements, licenses, or affiliations with the principal foreign makers of these products, one in England and one in Germany. Such arrangements would account for the absence of imports, except for sample or experimental lots, and might also limit export markets. 7. COUMARONE AND INDENE RESINS