Dr. A. L. Cardon – Senior Research Scientist – Retired
Text from: International Conference on Polymers and Molds Innovations
100 Years of Bakelite, Past and Future April 18, 2007
Leo Baekeland was very concerned about the legal rights of his inventions. More than 400 patents were published, and the numerous infringements by competitors were brought to court and almost always won by Baekeland. He proved to be an excellent patent specialist, in such a way that he was adviser for other companies in other domains suffering problems with patent infringements. It proved to be fruitful to theirs, as well as to his own profits.
What is so amazing about this famous patent Nr 942.699?
Well, according to me, it is …because it is visionary. If this knowledge would be removed from our civilization today, our world would simply stop. Look around you, and try to find applications that are not linked to polymers or the knowledge of polymers. It will be hard to find. Even our own body and brain is polymer history.
And the explosion of knowledge about polymers and their composites started the day this patent was published. It was not the first patent on polymer products, it was not the first patent on phenol-formaldehyde products and resins either, but it was a decisive breakthrough. It revealed 3 basic insights, in merely 2 ½ pages:
1. The importance of controlled conditions to make polymers
2. The importance of making composites with reinforcing agents
3. The importance of technology: impregnating, compounding and molding.
- Importance of Controlled conditions
As I told before, Baekeland had learned a lot by failures, from his own as well as from others. In his early days, especially in the time from his photographic developments, but also later at the start of his development of phenolic resins, he made numerous experiments, all trial and error, sometimes more than hundred, before he could make something that was more or less working the way it should. In this patent however, he lists the parameters that must be controlled, and for some part determines the ranges within which these parameters should be combined to get useful products. For me, it is the first step to what is called nowadays “Factorial design experiments” – to optimize chemical processes. He mentions types of catalysts, reaction temperature ranges, etc.
He describes how controlling these parameters leads to 3 different phases (later called A, B and C), that open the way to different applications areas; but all with the same resin. Simplified we can say that in the soluble and meltable stage A, the polymer can be used for impregnation and coatings. In the (partially) insoluble but still meltable stage B we can obtain compounded products that can be molded in a well-defined shape. In phase C we have the cured, unmeltable, dimensionally stable end product that is best known under the name “Bakelite”. Telephones, radio cabinets, design parts, jewels, household products like coffee machines, phonographic discs, pot and pan handles are well known historical examples. The cured varnishes and phenolic foams are a few of many other examples of the C stage.
- The importance of making composites
Baekeland was not only an excellent scientist, but also a very practical man. So he extensively describes which reinforcing agents can be used for making compounds or composite materials that can be molded to useful products. It is rather fantastic that every single reinforcement or treatment he mentioned, resulted in completely new application domains. Cellulose and wood fibers (wood treatment, impregnated wood, laminates, paper treatment, electrical switches, plugs and isolation boxes), asbestos (brake shoes and early pot and pan handles), rubber (tires and rubber modifications), minerals (billiard balls) and other fibrous materials (present day pot and pan handles, engineering materials and composites), carbon and graphite (tribological or selflubricating applications), mica (commutators), abrasive fillers (grinding discs), pigments and many more.
- The importance of technology
Baekeland describes compounding techniques (“similar to rubber compounding”), impregnation (with and without solvents, etc) and molding procedures (combination pressure and temperature to avoid blisters) to make useful products. All these techniques are partially used to this day, and have been optimized or have triggered new technologies
All developments in the polymer world, in one way or another owes tribute to this early publication.