Band-aid was invented by one of the employees of the company, named Earle Dickson, almost by accident. Meaning, it randomly occurred to him to invent band-aid. It so happened that Dickson's wife Josephine would often get wounded doing household chores and every time Dickson would have to cover the wound with cotton bandage that would loosen and fall off in some time. Assuming that this situation could be improved with sticking plaster, Dickson took a thick cloth, smeared an adhesive named crinoline on it and stuck plastic covering to it. Then cut it in shape of stripe and started using it for his wife's wounds. This was convenient as whenever his wife got a wound, he would cut the rolled bandage in stripe and use it on the wound, and it would stay stuck on the wound for days.
Johnson & Johnson bought rights of Earle Dickson's invention. Instead of a roll of bandage they started marketing it in the form of spare stripes in 1924 and named the product band-aid. At first it did sell much, but gradually it earned popularity around the world.