THE CHEMICAL WORLD THIS WEEK
Harold Narcus (center), Electrochemical Industries, comments on latest advances in the metallization of plastics, in answer to a question by Arthur S. Jacobs (left), Ideal Plastics. At right is John W. LaBelle, chairman of SPE conference C&EN REPORTS: Society of Plastics Engineers
Output of Metallized Plastics Continues Sharp u p w a r d Swing Engineering development of plastics must catch up with rapid advances in polymer chemistry BOSTON.—The production of metallized plastics, which amounted to an estimated 50 million pieces in 1952, is expected to rise to approximately 100 million pieces in 1953. These metallized items may range all the way from buttons and costume jewelry to loving cups and portable radio cabinets. According to Harold Narcus of Electrochemical Industries, Inc., metallized plastics offer many distinct advantages that in the future will ensure the greatly increased use of these materials. Speaking at the ninth annual technical conference of the Society of Plastics Engineers, held here on Jan. 21 to 23, Dr. Narcus indicated that the process of metallizing plastics is not intended to imitate metals but rather to yield products that cannot be made of metal economically. By the use of plastics, more intricate shapes can be readily molded and plated than can be fabricated easily in metal and electroplated. Since the weight added by the application of metal to the plastic is usually negligible, the metallized plastic part still maintains a weight advantage over a similar part made entirely of metal, he said. 424
By the plating of plastics, especially when use is made of metallic coatings of the proper type and thickness, the undesirable properties of some plastics, such as absorption of oils, solvents, and moisture, which may cause swelling or distortion of the basic organic material, are eliminated. The weatherability of the plastic is greatly increased. In addition, there is an increase in tt-nsile, impact, and flexural strength and in resistance to abrasion and to distortion under heat. Probably the outstanding advantage of
The Week's Events Rubber Industry Expected to Expand One Third by 1962 . . . .
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Production of W e e d Control Chemicals Increasing
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Biochemistry Awards to Be Presented at ACS Los Angeles Meeting . .
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Vacancy in O D M May Indicate Changes in Mobilization Set-Up
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metallized plastics, said Dr. Narcus, is the greater corrosion resistance of a metallic deposit when it is applied to a plastic material rather than to the usual metallic base. Resistance to salt water and industrial atmospheres is excellent since there is no electrolytic action. The inert, nonmetallic plastic base guarantees a longer life of the cuter metal coating and, hence, of the entire plated part. The metallization of plastics, said Dr. Narcus, has opened u p a large field of application in electrical engineering and electronics, particularly where electric insulators must be shielded against magnetic fields, high-frequency currents, or radium emanation. In these applications, articles molded of phenolics or styrènes, which are excellent insulators, are ordinarily plated with copper, cadmium, or lead. According to Dr. Narcus, such metals as aluminum and magnesium are being replaced, in part, by metallized plastics in aircraft electrical shielding and in radio shielding devices. The use of plated plastics eliminates the need for inserts and assembly operations to give a product that is light, quickly fabricated, and resistant to vibrations encountered in modern aircraft, This vibrational resistance. Dr. Narcus added, was of particular value in a metallized plastic-plywood antenna mast used in high-speed fighter planes. This mast was thickly plated with copper in some instances and with iron in others. Plating of Plastics. In general, three basic methods are available for the plating of plastics: chemical reduction followed by electroplating, the mirror spray method, and metal evaporation. The chemical reduction method involves the formation of a conductive film on a plastic surface by the reaction of an aqueous solution of the metal salt with a suitable reducing agent. For example, a silver film can be formed on the nonconductive surface ( after cleaning and pretreatment ) by the reduction of an ammoniacal silver salt, such as silver nitrate, with formaldehyde. After this film is formed, an intermediate layer of another metal, usually copper, is electrodeposited on the surface. Finally, a layer of the desired metal is electroplated on the outer surface. The advantages of the chemical reduction method are mainly the relatively low cost involved in the processing of small items without the necessity of employing plating racks and subsequent polishing operations. The method is usually used w h e n metallic coatings in the range from 0.G001 to 0.005 inch or even higher in thickness is desired. The mirror spray method—specifically, the application of brilliant silver films— involves the formation of a metallic layer by use of a specially designed spray gun. This gun is so arranged that the silvering and reducing solutions are either internally AND
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mixed and sprayed at the work through terials, whether of polymeric nature or not. tories. Polystyrene has had the fastest rate one opening, or the solutions may meet at Although the emphasis in plastics educa- of growth of any industrial material, with a vortex a few inches from t h e end of the tion should be o n fundamentals, attention the exception of magnesium during World gun and hit t h e prepared work as a filmmust also b e paid to the application of War II, he said. Production of polystyrene forming mixture. T h e main advantage of fundamental knowledge to specific induscame t o about 3 7 0 million pounds in 1951. this m e t h o d is the relatively low cost of trial problems, Mr. Maxwell said. A pro- Output in 1952 was higher—the first or the required equipment. gram similar to the one outlined b y the second highest of all materials in the plastics industry. The metal evaporation method, which educational committee has been in operaresembles in principle the better known tion at Princeton for seven years. At presAn increasingly important trend, in the cathode-sputtering method, involves the ent, Lowell Textile Institute a n d the Unipolystyrene industry today, Mr. Warner versity of South Carolina are i n the procdeposition of metals evaporated under consaid, is the development, of modified polyditions of high vacuum. "This procedure," ess of setting u p similar programs o n the styrene plastics—the so-called styrene alsaid Dr. Narcus, "has attracted w i d e at- committee's recommendations. loys. For example, the use of styrene tention during the past few years and topolyesters in electrical equipment is beA survey conducted by the S P E commitday is increasing tremendously in popu- tee on the present status of plastics educac o m i n g more and more widespread. Emlarity. It is strange that, in spite of the tion in the U. S. was summarized b y phasis is also being placed on the develfact that the principles of metal evapora- Charles C. Winding of Cornell. Of the opment of improved methods of fabricattion w e r e known for many years, the proc- 3 6 educational institutions covered in the ing polystyrene plastics. A possible fuess was not commercialized until the last survey, none had required undergraduate ture application, h e said, may be the use few years. Recent advances in high- courses devoted exclusively t o plastics. of polystyrene in refrigerator doors. vacuum engineering are probably the main T h e survey indicated that only 13 of the Glass-Bonded Mica. A molding comreasons for t h e sudden interest in this 3 6 schools provided laboratory courses, pound consisting of glass and mica is findmethod." much of the laboratory work involving ma- ing uses in high-frequency, high-temperaEducation in Plastics. A large, unfilled terials testing or chemistry. Only a very- ture applications, particularly where didemand exists today for technical personnel f e w schools had laboratory processing o r mensional stability is required. Accordwith plastics engineering training, said fabricating equipment. The committee has ing to J. H . Du Bois of Mycalex Corp. of E. S. Bloom of D u Pont, speaking at a found a very definite opposition t o t h e America, t h e high heat distortion point special symposium o n professional training introduction of any required specialized ( 6 5 0 ° F. ) of glass-bonded mica, its insert for the plastics industry. T h e demand for courses in the undergraduate curriculum. moldability, complete age stability, and trained personnel is bound t o increase sub- Accrediting committees warn against spe- low loss factor make it a useful structural stantially, said Dr. Bloom, w h o pointed to cialization in courses leading to general material for thermal, electronic, and highthe fact that 1952 plastics production was engineering degrees, said Dr. Winding. voltage applications. This market is also 2.6 billion pounds (that is, double the Polystyrene. T h e past 25 years of prog- being served by thermosetting resin1947 level and six times t h e 1942 total) ress in the development of polystyrene bonded mica compounds, as well as by and that by 1955 the expected output will plastics were summarized by A . J. Warner tetrafluoroethylene (Teflon), trifluorochlob e almost double that of 1952. Estimates of Federal Telecommunication Laboraroethylene ( K e l - F ) , and silicone glass. by the Paley Commission indicate a 1 0 0 0 % increase in plastics production during the next 25 years. In t h e plastics field» many people b e lieve that the chemical phase of development is now far ahead of t h e engineering. Thus, said Dr. Bloom, some of the greatest advances in t h e plastics industry will come H e r e is EXACT about through the engineering developWEIGHT'S new unit ment of plastics that are n o w available or for accurate automatic that will be coming into production in the packaging, weighing, near future. and checking of free T h e work being done by the educational flowing chemicals in open mouth bags up committee of SPE to promote the training to 150 lbs. T h e new unit consists of a time ot competent plastics engineers is an exproven heavy duty EXACT W E I G H T cellent start, Dr. Bloom said. Such work Scale (floor operation) with dial of 4 oz. should b e strengthened on the engineering over and under-weight by 1 oz. graduaside by increased emphasis on such mattions . . . automatic dustiess valve . . . ters as the fundamentals of plastics procdouble photo cell electric cut off. This essing or conversion, including the rheology of molten plastics and the heat scale, already in use in the great carbon transfer of these materials; the developblack industry, h a s many chemical indusment of an imaginative approach to n e w try uses in automatic packaging of all free product design; an understanding of the flowing materials where dust control is properties of plastics, such as their stressa factor. For full details write for time behavior; and on the concept that information covering Model 1324CB. plastics are important engineering materials of construction that have many as-yetundiscovered uses. T h e university program suggested by the SPE educational committee for the training of plastics engineers calls for t w o introductory undergraduate courses and 4:4ÉH:«»HM*HW«MgH-IST five graduate courses in plastics. In each case, said Bryce Maxwell of Princeton, t h e Mdkàiu : Κ « Τ · Μ « « f ï l 2 b i :Ι·Τ1 main emphasis is on broad fundamentals rather than o n specific know-how or procedure. In many cases, the course material is of such a fundamental nature that it can 954 West Fifth Ave., Columbus 8, Ohio be applied to nearly all engineering ma2920 Bloor St., West, Toronto 18, Canada
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THE CHEMSCAL WORLD THIS WEEK The miniaturization programs of the Signal Corps and the fast-growing demand for structural and functional components using silver pastes with high firing temperatures for printed-circuits have led to the development of glass-bonded synthetic mica. Natural muscovite mica and natural phlogopite mica, the commonly available types used for conventional glass-bonded mica products, have hydroxyl ions in their crystal structure, and this prevents hightemperature use. At elevated temperatures, natural micas tend to bloat and lose their strength. On the other hand, the synthetic mica, fluoro-phlogopite, has no hydroxyl ions and can be heated to temperatures as high as 2000° F . safely, said Mr. D u Bois. M y cal ex Corp. has leased the facilities of the Bureau of Mines at Norris, Tenn., to gain pilot-plant experience with t h e production of sythetic mica, preparatory to the design of full production facilities. A glass research program has been started at the company's Clifton, N . J., plant to enable the development of a suitable glass that will measure up to the high-temperature potentialities of synthetic mica. An investigation is also being carried out to determine the properties of synthetic mica filled with Teflon and Kel-F. Vinyl Floor Coverings. The earliest known vinyl floor installation, built in 1931, was a tile floor produced from a low-molecular-weight vinyl resin. At that time, the resin sold for about $1.00 per pound. Between 1937 and 1940, with vinyl resin costs down to 5 5 cents per pound, several flooring manufacturers produced limited quantities of this hard, seminexibie material. Shortly after World War II, with resin costs at 33 cents per pound, flexible vinyl tiles made from the highermolecular-weight resins were introduced. According to Robert K. Petry of Delaware Floor Products, the flexible vinyl tiles represent the highest quality and the highest priced vinyl floor products made commercially. They consist of about 50*7r of a plasticized high-molecular-weight vinyl chloride polymer and 509c of a color pigment and filler, together with necessary stabilizers, lubricants, and other additives. On the other hand, semiflexible tiles will tolerate as much a s 759^ filler. This factor, together with l o w processing costs, brings the semiflexible tiles into a lower price range than the flexible type and naturally results in a much larger volumj of production. The growing u s e of semiflexible vinyl floor coverings has accounted for a major portion of t h e total increase in vinyl flooring production during the past year, said Mr. Petry.
Correcf/of) . . . In the chart on page 234, Jan. 1 9 , 1953, heading the article, "Trichloroethylene," an error was made in the dimension of c a pacity. The capacities should be millions of pounds rather than thousands of pounds as stated on the chart. 426
D . L. Flanders, B. F. Goodrich Co. (second from left), shows some of the samples used in testing rubber additives to others on the morning program—E. C. Ray ( l e f t ) , who presided at the morning session, A. R. Davis, American Cyanamid, V. L. Peterson, Goodyear Tire & Rubber Co., and F. I. L. Lawrence, Kendall Refining Co. C&EN REPORTS: Commercial Chemical Development Association
Rubber Industry Expected to Expand O n e Third by 1 9 6 2 M a r k e t s a n a needs for c h e m i c a l * in p a i n t , a n d r u b b e r industries outlined CLEVELAND.—As a market for chemicals, the rubber industry is a big volume one; furthermore, it is an industry which has not reached its peak by any means, V. L. Peterson, Goodyear Tire & Rubber Co., told those attending the winter meeting of the Commercial Chemical Development Association here Jan. 22. Theme of the one-day meeting was the problems encountered in the commercial development of chemicals for the petroleum, paint, and rubber industries and what technical data suppliers of chemicals should submit to the industries in order to have their products accepted. The rubber industry can be considered a good chemical customer, Peterson said. Slightly over 1.2 million long tons of its basic raw material, rubber hydrocarbon, were used in 1952, and Peterson estimated consumption by 1962 will be 1.6 million long tons annually. Tins indicates the expanding market for chemicals and pigments that suppliers may expect, the present market for these materials being about $450 million annually. What some of the major products and their production volumes are, as given by Peterson, are shown in the table. What will be some of the materials chemical suppliers can develop for the industry for the future? Peterson said, "We will need accelerators, antioxidants, and C H E M I C A L
petroleum,
vulcanizing agents which will allow us to mix super-abrasion carbon blacks that haven't been developed yet. We will need a low-cost process for producing butadiene, or a substitute monomer for use in the production of GR-S. W e will need a white or light-colored pigment with higher reinforcing characteristics than anything on the market today." MATERIALS Antioxidants and accelerators Fatty acids Zinc oxide Plasticizers ( million gallons ) Solvents (million gallons) Carbon black
VOLUME Pounds Value (millions) ( millions) 130 30 160
$78 2.5 23
30
8
30 1000
4.5 80
Peterson also expressed the belief that a new chemical fiber will be needed for tire cords. He explained that the industry has gone through a revolution from cotton to rayon and is currently going through a revolution from rayon to nylon. However, nylon is just too expensive to use in tires and a new less expensive fiber is a real need. Latex Paint Development. The paint industry has moved from an art to a sciAND
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