How Erasers Made:

HISTORY:

In 1736, a French observed an south American native Indians using a certain tree material to make bouncing balls he brought that content home. On April 15, 1770, Joseph Priestley described the latex which had the ability to rub out pencil marks: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black lead pencil." He dubbed the substance "rubber".

In same 1770, Edward Nairne, an English engineer, is credited with developing the first widely-marketed rubber eraser for an inventions competition. He reportedly sold natural rubber erasers for the high price of 3 shillings per half-inch cube. According to Nairne, he inadvertently picked up a piece of rubber instead of breadcrumbs, discovered rubbers erasing properties, and began selling rubber erasers. Incidentally, this was the first practical application of the substance in Europe, and rubbing out the pencil marks gave it its English name.

On
March 30, 1858, Hymen Lipman of Philadelphia, USA, received the first patent for attaching an eraser to the end of a pencil. It was later invalidated because it was determined to be simply a composite of two devices rather than an entirely new product.

RUBBER EXTRACTION:

Rubber tree plantations are found only in tropical regions with high levels of annual precipitation. Malaysia is the leading producer of rubber trees. A rubber tree is tapped by cutting a thin strip of bark about 0.04 in (1 mm) deep off the tree as high up as the worker can easily reach. Later strips will be cut below the first one. Each strip reaches about halfway around the circumference of the tree and slants downward at an angle of about 30 degrees to allow the latex to drain into a container. If the latex is allowed to coagulate naturally, each cut will produce about 1 oz (28 g) of latex before the latex stops flowing after a few hours. A chemical may be applied to the bark to prevent the latex from coagulating, allowing it to flow for several days.

MANUFACTURING PROCESS:

RAW MATERIALS:

Measured fillers, accelerators, curing agents, oils, color and main agent is synthetic rubber.Then regular vegetable oil is added with sulfur  and calcium carbonate as a filler.

MAKING:

The raw materials and if any previous manufacturing defect erasers are found, then they also added with the ingredients and rolled in hot rollers to make soft and brought as a mixture of rubber sheets. Then sulfur is added along with vegetable oil and calcium carbonate is mixed along with the mixtures as a securing agent and as a fillers. Once the mixture came to a perfect form i.e. in both color and softening they are rolled up by the workers. These first step process of mixture is been done for about 10-20 min's.

Then the rubber sheet is cut'd into a square shape and weighted, which should be around 11-18 pounds. This weighing represents the quality check and also says the correct order of Rubber.

  

Then the cut'd square rubber is placed in heated steel press for 20 min's and when the steel press process is completed they remove the excess rubber. The heated steel press make the rubber hardened in its polymer structure. 
Then the heated rubber sheet is been allowed to immersed in the cold water which makes the rubber as an soft agent which also makes them make an close impact in its molecular structure. Now they are ready for next process i.e. they are ready to become an individual members. Confusing.? simple big square sheet rubber is been cut'd into small piece of Erasers.


HOW BLUE ONE IS MERGED WITH PINK ERASER ?

To erase the both lead & ink they cut double stretch of rubber one pink and blue. These double stretched rubber is again kept in the Hot Steel press and pressure is applied to it. These steel plate is kept alone for 20 min's and once the time is over they are taken out and excess rubber is been removed.

Double side eraser is one kept in the cutter which will separate them into individual Eraser. Now the Double side eraser is now ready.

Now these individual Erasers are allowed to put in a big barrel and some powder agent is added in the barrel and they rotated for around 15 min's. This process makes the Erasers into a Non-Sticky one. Now they are ready for final process and once the final process is finished they are ready for Market. Thinking What Process is That..? Yes, You are right its company label printing. Now You use your Eraser.