Japan's invasion of Indochina cut off the U.S. supply of:

Japan was chronically short of raw materials, so invading Indochina was a way of remedying this deficiency. The oilfields of Indonesia were also a target for the Japanese; they would need a regular supply of oil to conduct their increasingly ambitious military plans. But the Japanese invasion of Indochina had a particularly damaging effect upon American trade. The U.S. auto industry was heavily dependent upon a regular supply of rubber from Indochina, as this was used in the manufacture of tires. In fact, at the start of World War II, Malaya—which was part of Indochina— was responsible for 40 per cent of the world's production of rubber, meaning that any disruption of supply routes would have a serious effect upon the international economy.
Japan's lightning invasion of Indochina alerted the Americans to the dangers of Japanese expansionism. It was this that led directly to the international oil embargo placed upon Japan by the United States and other countries, and which in turn was one of the factors behind Japan's fateful decision to attack Pearl Harbor.
http://factsanddetails.com/asian/ca67/sub427/item2534.html