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Source
There are many varieties of plants that yield natural
rubber. However, the best and preferred source is Hevea
brasiliensis. This tree is originally from Brazil and has
now been transplanted in many areas all over the world and is
the source of most of the natural rubber produced in the
world. Indonesia, Malaysia, Thailand, India, Sri Lanka and
China are among the chief rubber producing countries of the
world. Tapping and
processing
The process of extruding latex from trees is called
tapping. One tapping yields about 30 milliliters of latex,
after which a thin strip of bark is removed from near the
bottom of the cut. Then the tree is retapped. This process is
repeated on every alternate day. As the cuttings reach ground
level, the tree is left alone for a while for renewal and then
tapping is resumed at a new spot.
Another familiar scene is that of small off-white sheets being put
out to dry on the clothesline. These sheets are the next stage in
the rubber production process. The latex that is gathered from trees
is diluted with water and then treated with acid. As a result the
rubber particles are separated and they clump together. This is
removed and pressed between rollers to get the sheets we see drying
outside. Rubber’s indelible
story and its indispensability
Man has used rubber for a long time now. Native South Americans
used it for making water resistant shoes, coats and other clothing
items even before Columbus visited America. An offshoot of the
voyages of Columbus was the import of rubber to Europe. However, the
Europeans were not able to put it to productive use like the native
South Americans. Columbus visited America in 1492 and it was only in
1731 that an expedition was embarked upon by the French government
for the sole purpose of learning how to use rubber. Now there was no
looking back.
The year 1770 is
significant for us in a different way. That was the year that saw
the birth of the indispensable pencil eraser – a use of rubber
discovered by British chemist Joseph Priestley. And it was this
property that earned it the name rubber.
The year 1761 saw Samuel
Peal, an English businessman patenting a method of waterproofing
cloth by using rubber solution. It was, however, a little wait of
more than sixty years before the raincoats were designed. This
happened in the year 1823, brought to us as raincoats or Macintoshes
as they are also known after their inventor Charles Macintosh a
British chemist.
The vulcanization
process invented by Charles Goodyear in 1839 ensured widespread
commercial use of rubber. Rubber has now found many uses, some of
the common ones being – tires for vehicles, electrical insulation
and shoe soles. |
