I think early on the mentality was not so much the desire to die in battle, although it was an influence. Really the Japanese had a bone to pick with the western powers, and with the United States in particular. It was born out of the perception that westerners saw the Japanese as inferior, which given the racism of the time, was largely valid. Japan thought it had earned the respect of the west after the Russo-Japanese war and Japanese participation in World War I, but Versailles and subsequent treaties proved that was not the case. Add to that the forced opening of the country by the US, and the result was a culture that felt it had to prove itself by defeating another major power, with the US being the obvious target.
Had Japanese leadership not been so obsessed with the United States as an adversary, they might have achieved their goals without even fighting them. The Americans were not going to get involved in a war unless they were directly attacked, and all the resource-rich territories were British and Dutch possessions. Had they left the Phillippines alone, they could have taken Burma, Borneo, etc. without US interference and secured the resources they wanted. It's not like the US would try to blockade them from the Philippines without a declaration of war.
But the Japanese mentality was that if they wanted an empire in the Pacific, they would have to fight the Americans sooner or later, and with the Navy and Army at their apex, they figured late '41 was the time to try it. Had they thought a bit more strategically, they could have had their empire without fighting the US.