Synthetic resins and their raw materials / A survey of the types and uses of synthetic resins, the organization of the industry, and the trade in resins and raw materials, with particular references to factors essential to tariff consideration. Under the general provisions of section 332, title III, part II, Tariff act of 1930.

by United States Tariff Commission

⁷ Not available because of absence of export figures. Exports probably negligible up to 1929; substantial in 1933.

The manufacture of synthetic phenol was revived about 1923. Imports were quite small as compared with production, especially after 1927. At first this was probably due primarily to the protection given by the duty which had been increased in 1922.[22] But with the increase in volume of production in the United States the price decreased and since 1933 the United States producers have enjoyed a substantial export business. It may therefore be doubted that in recent years there would have been any substantial imports even if phenol had been free of duty.

THE CRESOLS, XYLENOLS, AND CRESYLIC ACID

Reference to table [56], page [109], will show that, as distillation of coal tar proceeds and the temperature of distillation is increased, the phenol fraction is followed in order by the three cresols and then by the six xylenols. Each of these tar acids is a definite chemical compound with definite physical properties. Consideration of them as raw materials for synthetic resins is complicated by the fact that they are generally used in mixtures and that the commercial term, cresylic acid, applied to many of these mixtures has no definite relationship to the precise chemical terminology. Yet since the term cresylic acid is so widely used in commerce, since the tariff provides for imports under that name, and since the statistics available are in part in terms of cresylic acid and in part in terms of cresols and xylenols it is impossible to present the complete picture on the basis of the correct chemical terminology.

Description and uses.

The cresols.—The cresols are isomeric tar acids obtained from coal tar by fractional distillation. Their combined content averages about 1 percent of domestic coal tar. The total cresol content is divided in about the following proportions: 40 percent metacresol, 35 percent orthocresol, and 25 percent paracresol. The cresols are marketed in a number of types and grades including mixtures of ortho, meta, and para; mixtures of meta and para; separated ortho, meta, and para; and also in mixtures with phenol and the xylenols.

Metacresol (chemically, 3-methyl phenol) is a colorless to yellow liquid with a phenol-like odor. When pure, it melts at 11° C., boils at 202.8° C., and has a specific gravity of 1.03. It is used in the manufacture of synthetic resins, photographic developers, explosives, disinfectant soaps, paint and varnish removers, to remove ink from newsprint, to soften and reclaim rubber, and in intermediates for dyes and perfume materials.

Orthocresol (chemically, 2-methyl phenol) is a colorless, crystalline product with a phenol-like odor, melting at 30° C., boiling at 190.8° C., and having a specific gravity of 1.04. It is used in the manufacture of coumarin (flavor), antiseptics, disinfectants, and fumigants. It is not used to any extent in synthetic resins.

Paracresol (chemically, 4-methyl phenol) is a colorless, crystalline substance with a phenol-like odor, melting at 35° C., boiling at 201.8° C., and having a specific gravity of 1.03. It is used in the manufacture of intermediates, dyes, disinfectants, and fumigants, in medicine, and in mixture with metacresol in synthetic resins. Domestic production of synthetic paracresol was announced early in 1938 by Swann & Co., Birmingham, Ala.

Metaparacresol is a combination of approximately 60 percent meta and 40 percent para cresol obtained in the fractional distillation of mixed cresols. The ortho isomer is distilled off, leaving a residue of metaparacresol. It is widely used in the manufacture of synthetic resins.