The appearance of pencils has a history of about 400 years, and the appearance of erasers is about 200 years later than pencils. In the 200 years before pencils and erasers met, people used bread or sponges to erase pencil marks. It is not so much to wipe off the traces as to make the graphite traces fade by friction. It was not until the end of 18 that people began to make rubber from rubber.
Long before Europeans arrived in the New World of America, people in Central America and South America began to use rubber. This kind of rubber is called? A weeping tree? This liquid is used by Indians to make elastic balls, or to bond tools and clothes. Some people pour rubber into molds to make shoes and various containers.
1493 When Columbus discovered the South American continent, he saw all kinds of rubber products there, but about 300 years later, Charles? De? Charles de la Condamine formally described rubber in his book "A Brief Introduction to Travel in South America", calling it? Natural rubber? Latex, a milky white liquid produced under the bark of the tropical New World, brought rubber samples back to Europe.
1770, British scientist Joseph? Priestley accidentally discovered that rubber can erase the handwriting written by pencils and issued a statement saying? It only takes three shillings to buy a small piece to witness the eraser erase the pencil handwriting. ? Thus, in Britain, rubber as a magical thing to erase handwriting began to be recognized by people and gave it a new name? Eraser? .
Until the end of 19, pencils and erasers were separated, and the prototype of pencils with erasers appeared in 1858. At that time, a man named Hyman in Philadelphia, USA? Hyman lippman applied for a patent. He carved a groove on the tip of the pencil and then stuck an eraser on the groove.
However, the patent was later withdrawn on the grounds that the pencil and eraser were simply glued together without any improvement in function, so it was impossible to apply for a patent. This decision is bad news for Leapman, but for many pencil manufacturers, new business opportunities are just around the corner.
1867, J. B. Blair invented a hollow eraser into which a pencil can be inserted. Eagle Company, a pencil manufacturer at that time, immediately put the invention into production, and a pencil with an eraser was officially introduced and was very popular. Until today, about 90% pencils in the United States have erasers, and pencils without erasers are more common in Europe.
Now rubber is still its main raw material, including natural rubber and synthetic rubber. Synthetic rubber is made of styrene and butadiene, zinc oxide and titanium oxide can make rubber white, iron oxide can make rubber red, and various organic dyes can make rubber colorful.