CAST PHENOLIC RESINS
Process of manufacture.
The production of cast phenolic resins requires pure materials, expensive equipment, and extreme care in the control of the operation. A mixture of phenol and formaldehyde and a catalyst (usually sodium or potassium hydroxide) is charged into a nickel-lined reaction kettle and heated until the water separates and is removed. The reaction is then allowed to proceed to the desired point. Glycerin is added to aid in forming a transparent product. All equipment, including pipe lines, valves, and pumps, is nickel or nickel lined except that used for formaldehyde, which is made of aluminum.
The resin is usually made in 1,000 pound batches, and the reaction cycle ranges from 6 to 18 hours. It is colored with soluble coal-tar dyes and cast into lead molds. These are placed in a heated room and allowed to cure for 3 to 6 days. The resin is removed from the mold with air hammers, and the lead molds are melted.
The appearance of the resin may be changed by varying its water content, by the addition of dyes and fillers, and by the addition of other substances to produce some desired effect, such as imitation ivory or marble. The clarity of the resin depends upon its water content—the greater the degree of dehydration the clearer the product. Range of colors is complete, from crystal clear to the darker shades, with any degree of transparency, translucency, or opaqueness.
Casting is in the form of sheets, rods, tubes, or special forms suitable for the production of buckles, jewelry, and other small products. Molds of complicated shape cannot be used, which means that most articles if produced of cast resin must be produced from standard shapes by subsequent working. Recently small radio cabinets have been cast.
Uses.
Cast phenolic resin can be machined in the same manner as hard wood. It must be polished after machining, usually by tumbling with shoe pegs and pumice or with muslin wheels. The smooth finish and low degree of heat conduction give the material a pleasant feel, not cold to the touch as is metal. The coloring is not superficial and therefore does not chip or wear off. Electrical properties are excellent. A slow polymerization continues for some time after fabrication, resulting in slight shrinkage.
Cast phenolic resins are marketed by the producers as rods, sheets, cylinders, and special castings. Standard round rods range from ⅜ inch to more than 5 inches in diameter. Special rods are available in such forms as square, hexagon, octagon, and fluted. Standard sheets are in sizes from 12 by 24 inches to 36 by 72 inches, and from ⅛ to 1 inch thick. Stock cylinders are available in a wide range of inside and outside diameters.
Cast Phenolic Resins, Standard Shapes and Small Articles Fabricated From Them.
Source: Bakelite Corporation, 247 Park Avenue, New York, N. Y.
Stock material is fabricated by a number of firms into an endless variety of articles. Among these are toilet articles such as combs, backs for brushes, cosmetic containers, and trinkets; fittings for automobiles, electrical appliances, furniture, and display fixtures; jewelry, dress ornaments, clock cases, handbag frames, vanity cases, smokers’ articles, signs and advertising specialties, picture frames, handles for cutlery, chessmen, pens, desk penholders, pencils, and many others. Probably the largest consumption is in the making of buttons and buckles.
The cast phenolic resins are odorless, tasteless, nonflammable, resistant to oils and greases, and practically nonbreakable.
Patents and licensing.
The basic patent covering the manufacture of cast phenolic resins is United States Patent No. 1,854,600, issued April 19, 1932, to F. Poliak and A. Ostersetzer, of Vienna, and assigned to Pollopas, Ltd., of London. Many other patents have been granted on variations and modifications of this one. The basic process is also patented in England, France, Germany, and other countries.
United States and Canadian patent rights were purchased by the American Catalin Corporation; German rights by the Interessen Gemeinschaft Industrie A. G. (German I. G.); French rights by Kuhlmann Co., and British rights by the Imperial Chemical Industries. These licensing arrangements limited the licensee to sales in his own and, in some instances, nearby countries.
The American Catalin Corporation has successfully defended the validity of this patent and has licensed a number of domestic manufacturers to produce cast phenolic resins on a royalty basis.
In 1937 there were seven domestic makers of cast phenolic resins located in New Jersey, New York, Massachusetts, and Pennsylvania. These firms produce and market resins under the following trade names: Catalin, Prystal, Joanite, Fiberlon, Phenolin, and Marblette.
Production of cast phenolic resins.
Production was initiated about 1929 by the American Catalin Corporation. The output increased substantially every year from that year through 1933. Statistics of production and sales are not publishable for the years prior to 1934 because they would reveal the operations of individual firms; they are given in table [6] for subsequent years.
Table 6.—Cast phenolic resins: United States production and sales, 1934-37
| Year | Production | Sales | ||
|---|---|---|---|---|
| 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.