[Trade Journal]
Publication: Engineering News
New York, NY, United States
vol. 64, no. 26, p. 717-718, col. 1,1-2
The New Insulator " Bakelite.”
With the incorporation of the General Bakelite Co. , in New York, and the Bakelite Gesellschaft m. b. H., in Berlin, an interesting invention enters upon its real commercial career. The original paper describing it was read by Dr. L. H. Baekeland on this subject, before the American Chemical Society . More than a year has elapsed since, and considerable progress has been made on the practical side of the question. A brief, up-to-date description of "Bakelite" is not out of place.
"Bakelite" is a new substance, which, in its different forms, offers the advantages of hard rubber, Japanese lacquer, celluloid and in many respects excels the properties of these products. It is not merely a mixture of a so-called "compound" like so many rubber, shellac, or other resinous compositions, but a well- defined chemical substance of specific properties; it thus adds an import ant member to the industry of plastics.
In the synthesis of " Bakelite, " we have a more recent instance of a laboratory reaction, which seems to run along lines parallel to those of the delicate physiological changes which occur in plant life; it has some relation to the subtle process which in the Japenese lacquer tree engenders the substance known under the name of Japanese lacquer. Up till now the latter has been a product of limited applications, and an article of luxury, on account of its excessive price, and scant supply. Henceforth a new material has become available which can be manufactured in practically limitless quantities and at a price which allows a wide range of uses.
The laboratory method is an improvement on nature's process, not only because the reaction is quicker and less expensive, but the resulting artificial product is decidedly more resisting to chemical and physical influences.
Dr. L. H. Baekeland, the inventor of this process, has a record of more than a quarter of a century of research in the field of pure and applied chemistry. To those outside of the chemical profession he is more particularly known through his inventive commercial achievements in the industry of so-called gas - light photographic papers, of which " Velox " is the best known representative.
The word "Bakelite" was selected as a simple trademark for the longer and less expedient chemical name oxybenzylmethylenglycolanhydride.
For the layman it is somewhat startling that in the formation of "Bakelite" two strong smelling liquid substances (carbolic acid and formaldehyde) should, under certain well-defined conditions, react chemically upon each other and solidify to a transparent amber-like solid substance entirely devoid of odor and taste.
The Bakelite process involves the utilization of three distinct and well-defined varieties designated "Bakelite A," "Bakelite B" and "Bakelite C. " "Bakelite C" is the final product, where as "A" and "B" are the transition products, which enable us to mold or otherwise apply the material before its final condition.
"Bakelite A" is the initial raw material and exists in liquid, pasty or solid condition. Every variety of this, if heated at a sufficiently high temperature changes into "B," then into "C." All varieties of "A," whether they be liquid, pasty or solid, are still soluble in alcohol or ace tone or in caustic soda, and behave as true resins.
Solid "A" is characterized by the fact that it is solid at ordinary temperatures, but melts if moderate heat is applied and stronger application of heat makes it infusible and insoluble, by transforming it into "B" or "C."
"Bakelite B" is an intermediate solid product. It is neither so hard nor strong as "C," and may be easily mistaken for Solid "A," but it is different from the latter on account of its insolubility. Furthermore, it is infusible, although the application of heat may temporarily soften it, without, however, bringing it into fusion. Solvents do not dissolve it, but some of them, like phenol or acetone, may soften it or swell it, without bringing it into solution. "B" is specially characterized by the fact that although it is infusible, it will soften under the action of heat and then will mold and weld together if pressed in a hot hydraulic press. The latter fact differentiates it clearly from " C."
"Bakelite C" is the final product, resulting from the application of heat to "A" or " B, " and may be considered as a chemical polymer of " B' resulting from a multiple molecular grouping. It is no longer a resin, because it lacks all the chemical characteristics of a resin, although physically it may resemble amber. In pure form, and if made from the first member of the phenol group, its chemical formula is represented by C.3H3807.
The various uses of "Bakelite" will be better understood if we mention summarily some of its properties.
The final product, "Bakelite C," is infusible and can resist temperature of 572° F. (300° C.) or over. It is insoluble in all solvents, and can withstand strong chemicals, oil, hot water, steam, etc. All this in conjunction with its dielectric properties make it an excellent electrical insulator. It can be compounded with various filling materials and shaped or molded, with great accuracy to articles of unusual strength. It can be sawed, turned and polished.
It can be used to impregnate wood and other porous bodies, rendering them harder and more resisting to chemical and physical influences. Or it can be obtained as transparent as glass, or colored to suit special requirements.
It can be purchased at a reasonable price, the latter varying with its different qualities.
Although "Bakelite" is stronger and harder than celluloid or hard rubber, it lacks the unusual flexibility of both of these plastics. Rods or plates made of it, or its compositions, are somewhat flexible, but considerably less so than celluloid or hard rubber. On the other hand, it withstands incomparably better, high temperatures and in general all chemical and physical influences, and has the further advantage of not being attacked by solvents nor by most chemicals. It does not emanate sulphur like hard rubber, nor nitrous products like celluloid, which have a very disturbing influence in some electrical applications. If heated in a flame, it does not suddenly catch fire like celluloid nor melt like rubber; it simply chars, then burns with difficulty.
During the act of hardening, which engenders the final product, there is a shrinkage of about 2 per cent. in diameter, or in length. This shrinkage can be lessened by the judicious incorporation of filling materials, and if the latter be used in large amounts, the decrease in volume can be reduced to such a point as to make it hardly perceptible. Its specific gravity is about 1.25.
Although the preparatory work connected with the industrial side of the process has been going on with strenuous application since 1907, it was thought advisable not to jeopardize everything by a too hasty, broad cast introduction, before each industrial use had been studied for a sufficiently long time, on a practical commercial scale. This conservative way of proceeding is not always followed by those who are not sufficiently aware of the enormous distance that exists between a laboratory conception and the practical utilization thereof.
In the meantime, "Bakelite" has been used continuously during the last two years, especially for electrical purposes, while undergoing the test of time and the critical observations of every-day practice under the eyes of specialists. This work has been conducted on a sufficiently large scale to remove all doubts as to the practical side of the question.
"Bakelite" electrical insulators as well as pump valves, and other molded goods are now obtainable from several licensees, and some electrical manufacturers have begun the practical impregnation of coils, dynamos, motors, etc.
The General Bakelite Co. will limit more specially their attention to the chemical side of the process manufacturing the raw materials, just far enough that the users thereof can limit their attention to the mechanical side of the problem. A factory plant is being equipped now at Perth Amboy, N. J., but in the meantime the manufacturing is being carried on in Yonkers. The offices of the General Bakelite Co. are at 100 William St., New York City.
