This is the second in a series of articles on synthetic fibers and how they relate to shaving brushes, including a brief history of synthetic fibers, their development, stagnation, and resurrection in the market place. In the previous article, the discussion was based on the creation of new fibers for the replacement of increasingly hard to obtain items. Silk was becoming a major issue with the Japanese and Chinese were in armed combat during the 1930s. On another front, Russia was a primary source of natural fibers including badger, horse and boar. Due to the anthrax deaths attributed to Russian horse hairs, along with the communist take over of that country, eliminated it as a source of importation [Note from Mantic59: take a look at the fascinating story of the death of a former United States Congressman due to an infected shaving brush in the first source listed at the end of this article!].  New sources of fibers had to be found to replace these sources of supply. In addition the world was in for a major supply strain when World War II began in 1939.
In July of 1941, Japan, which was in full control of Manchuria, cut off all exports from that area in preparation for war. So brush manufacturers of all types, from brooms, mops, toothpaste and even shaving brushes, were beginning to feel the effects of embargoes and lack of open markets.  Nylon was being looked to for other things besides sheer fabrics. Development of Nylon fibers and bristles were also being developed for substitution for various applications to replace boar bristles. When the war began for the United States, Nylon supplies were taken over by the War Department to be used for parachutes and rope replacements. Brush makers would have to supply the most critical needs of the military during the war period and consumer goods including shaving brushes would simply be drastically reduced or eliminated from production all together. 
Following Allied victories in World War II, the economy shifted from war production to consumer product production especially in the United States. Nylon fibers used in ropes would now began to see its way into the cosmetic market through the domination of the toothbrush sector. These were made from Nylon stock that was rejected in the development of sheer materials so this rejected material was now carrying its own weight in the replacement of boar bristles in toothbrushes.  During this time, China fell to the Communists, and now two major suppliers of bristles were eliminated from shaving brush makers. One substitution would be to use the Nylon which production capability was ramped up during the war to make replacements for boar bristles. The Nylon fiber was closer to a boar’s bristle based on the amount of backbone they could provide. Sadly other qualities such as water retention and even softness was not pursued. The Nylon shaving fibers were produced with the same method as the toothpaste fibers only with longer tips. This was received with a moderate amount of acceptance, however, the shaving community did not accept this fiber as a major challenge to any natural brush.
This style of brush would remain the dominate synthetic brush for nearly the next fifty plus years due to the invention of another product. We will discuss that in a future article.
 DEATH BY SHAVING Former Congressman Michael Francis Farley’s Brush with Anthrax in 1921
 Bristles and Brushes: A Footnote to the Story of American War Production – Merrill Denison pages 44 – 45.
 Bristles and Brushes: A Footnote to the Story of American War Production – Merrill Denison pages 78 – 79.
 Bristles and Brushes: A Footnote to the Story of American War Production – Merrill Denison page 107.