Is the eraser made of rubber?
In the United Kingdom and Australia, the eraser is called rubber (rubber, eraser), but in the United States, the name of the eraser is eraser.
In 1770, Edward Naime, a British engineer, inadvertently picked up a piece of rubber to wipe the pencil marks, which had previously been customary to do with breadcrumbs. So the British began to produce and sell erasers, edward Naime is considered the inventor of the eraser.
The original eraser was not very convenient, and unprocessed rubber was prone to decay, until 1839, when inventor Charles Goodyear discovered that vulcanization could improve the quality of rubber, and the eraser became reliable.
In 1858, Lippmann from Philadelphia, USA, obtained a patent for embedding an eraser in the tail of a pencil, but the pencil with the eraser was later patented because it was judged to be "just two existing things embedded together and not a new product".
The first is the traditional vulcanized rubber
1. Mix rubber with ground pumice powder (spongy rocks condensed by magma, containing silicates, which can make rubber slightly rougher), iron oxide (which can make rubber turn pink), vegetable oil, sulfur and other substances.
2, heat the mixture, so that sulfur and rubber mixed, to increase the strength of rubber, make it more durable.
3, the soft, still hot raw materials into the press (extruded into a die), do a long and thin rubber special draft, and then use a knife to cut the rubber strip into small pieces to get the eraser.
The second is plastic (PVC) with plasticizer
Yes, plastic, not rubber!!! The plastic block itself is relatively brittle and hard, the polyvinyl chloride (PVC) heating softening, and then adding plastic additives, these additives are non-toxic, and most of the industrial use of synthetic resins and rubber have good compatibility. It has a good softening effect on plastic products.
Friendly tip: plastic erasers cannot be put together with plastic ruler stickers!
The eraser used by students is often scented. This fragrance is a volatile oil, if the plastic and the eraser are put together for a long time, the oil (organic solvent) volatilized by the eraser can dissolve the plastic in a small amount, which causes the eraser we see corroding on the stationery.