Eraser

An eraser (ugs. also eraser, Ratzefummel ) is a specially prepared rubber, with the lines drawn with a pencil or with ink from a carrier medium (usually paper ) are removed. A distinction is made between rubber and Kunststoffradierern.

History

In 1770 discovered the Briton Edward Nairne, that rubber is suitable for removing pencil marks. The British naturalist Joseph Priestley made ​​this discovery public after an observation in the same year and, therefore, has long been regarded as the inventor of the eraser. Already in the middle of the 16th century to have been satisfied with bread the same function.

Technology

The emitted from the pencil to the paper graphite adhere there by the force of adhesion. Since the rubber eraser has a higher adhesive force than paper, it attracts during mechanical abrasion (Latin radere: scrape, scrape ) the graphite away from the paper. Optimum Radierergebnisse a ruler should be placed parallel to the paper Radierbewegung ( possible by the tensioning of the paper, with two fingers ). This ensures that the paper under the eraser does not make waves and thereby tearing.

Ink and Tuscheradiergummis are mixed with ground rigid materials such as glass, pumice or quartz to abrade the paper described in fine layers. Removable is practically all boundaries are here only by the depth of penetration of the dye and set the thickness of the paper. The Schleifradieren damaged the paper surface and is then - in particular when using pinstripe paper - seen.

Erasures of ink drawings in addition to the mechanical grinding a physico- chemical process plays a role in which the ink line is partially dissolved and faded.

Radierknete

Radierknete is a plastically deformable eraser as plasticine.

Electric eraser

The Radiervorgang can be mechanized by using the Radierkörper is set in motion by means of rotation or oscillation generated electromagnetically. This is possible by means of devices with mains and on batteries or accumulators.

Production

Kautschukradierer made ​​from the milky sap (latex ) of rubber tree (Hevea brasiliensis) and Faktis, a white- yellow mass produced from vegetable oils. After addition of sulfur, the mixture is heated under pressure to about 150 degrees Celsius. This process is called vulcanization. The malleable rubber composition is thereby an elastic material. To enhance its abrasion, quartz and other fillers such as chalk, as well as dyes of the rubber compound are added.

Plastic eraser usually consist of polyvinyl chloride plasticized (PVC -P ), which is elastic by the addition of plasticizers.

Erasers as a toy

In the United States is since spring 2011 collection of erasers in animal and other shapes in the trend, which is particularly common among school children. The idea for this product comes from Japan, where appropriate erasers had been taken earlier in the market.