GUTTA
PERCHA
Gutta percha was
obtained from a variety of guttiferous trees
throughout the Pacific Rim although different
varieties produce materials of differing quality.
The differences generally reflect the quantity of
resin in the product with that from Pahang having
the lowest resin content. Balata has one of the
highest resin contents and was obtained from
trees in the tropical regions of South America.
There is much
confusion in the literature, and amongst
collectors, as to “what gutta percha is”.
In practical terms, and when addressing
collectors’ items, the material is probably
the whole residue from the latex, dried after
collection from whichever tree was its source.
This material tends to range from dark yellow
through red to black. It is possible that it has
undergone some degree of purification but, given
the variations in initial composition, it would
be extremely difficult to confirm this, even by
detailed chemical analysis.
In the same way
that commercially available natural rubber is
some 95% cis polyisoprene, the crude gutta percha
was often 30% to 50% trans polyisoprene. That is
it has the same chemical “building block”
as natural rubber (C5H8)n but with a different
spacial configuration. Isolation of the pure
trans polyisoprene gives a white/very pale cream
“cheesy” material which looks and feels
not unlike a block of high density polythene (m.p.
about 135°C) or polypropylene (m.p. 168°C). The
hard gutta percha softens at relatively low
temperatures (>71°C) and could then easily be
moulded or extruded (the screw extruder was
invented in 1845). At slightly lower temperatures,
around 60°C, it can easily be cut whilst at room
temperature it reverts to a hard material.
It is generally
believed that a British surgeon, Dr
William Montgomerie, was the first person to introduce
the Western world to gutta percha in 1843.
However, that honour actually belongs to John
Tradescant who had returned from his travels in
the Far East with this material in 1656. He
called it “mazer wood” but it then was
regarded as only one of many plant curiosities
and it was left to Dr Montgomerie to appreciate
its potential. He originally saw the material in
Singapore, in 1822, and learned its Malay name -
gutta percha - but he forgot about it when he
transferred to the Bengal Residency. When he
returned to Singapore he remembered the material
and how the workers had made handles for their
machetes with it. It struck him that there was
potential for its use both as knife handles and
for various medical devices. After some
experimentation he referred his work (in 1843) to
the Medical Board of Calcutta and copied the
documents to The Royal Society of Arts in London
through his brother-in-law. The Society realised
the potential of the material and promptly
awarded Montgomerie its gold medal. At about the
same time, Dr Hosé d’Almeida submitted
similar studies to the Royal Asiatic Society
together with some samples of gutta percha. Early
experiments in England with the gutta were not
very successful but in Paris, using Montgomerie’s
data, several medical instruments were
manufactured.
Once the
technology was understood, things moved rapidly
and later that year Hancock& Bewley formed
The Gutta Percha Company in the UK. In 1845 Lagrénée
returned to France from China and brought with
him some gutta percha which he too had found in
Singapore. His named the material “gum
plastic”. In the following year we can
record the first gutta percha patent - taken out
by Alexander, Cabriol & Duclos for a laminate
consisting of three layers: gutta-fabric-gutta.
Unfortunately they considered gutta to be akin to
rubber and overlooked the fact that its plastic
qualities were quite different from the elastic
properties of the latter. As with the early days
of rubber, it looked as though gutta percha was
not going to be of much use.
However, Gutta
percha had properties which could be exploited
and three of these, together with its softening
at easily attainable temperatures, provided its
three main areas of use until each was superseded
by advances in synthetic plastic materials.
The three
properties were its hard “plasticity”,
its electrical insulating properties and its
extremely low coefficient of thermal expansion/contraction.
These were exploited in quite different ways; the
first in the manufacture of golf balls, the
second in the manufacture of telegraph cables and
the third in the making of moulds, dies and
castings where the final (cold) product was
dimensionally identical to the moulded (hot) one.
This last area was of considerable importance
because of the extreme delicacy and detail which
could be included in the mould and then copied by
the new “electro-metallurgical” process.
The first gutta
percha golf ball, known as a “gutty”
was hand moulded by J Patterson in Scotland in
1845 and was just a smooth ball. Previous balls
had been made of wood, then leather stuffed with
feathers and these took a couple of hours or so
to make. The rapid introduction of metal moulds
meant that one person could turn out 10 or more
per hour which drastically reduced their cost and
was a significant factor in the expansion of the
game’s popularity. In the 1860’s it was
discovered that cutting groves in the ball
improved its flight. Again, this was originally
done by hand but by the 1890’s the pattern
was built into the moulds. Early in the 1900’s
a new ball was introduced which had a core of
stretched natural rubber thread and the era of
the gutty was over. In 1845 W Siemans suggested
gutta percha as telegraph wire insulant and two
years later WH Barlow & T Forster took out a
UK Patent for the making of telegraph cables with
gutta percha. In the same year JJ Craven, working
in the UK, insulated undersea cables with gutta
percha and in 1849 R & J Dick gave us the
first recorded use of gutta percha as a telegraph
cable insulant (in London). The following year
they founded R & J Dick Ltd. Gutta Percha and
Balata Manufacturers.
At the same time,
J and JW Brett were preparing to lay the first
gutta percha insulated cable from Dover to Calais.
In 1850 they made their first attempt, which
failed, as did their second the following year.
However, they were able to repair this and so
began a new era of communication. In 1858 CW
Field used the ship “The Faraday” to
lay the first transatlantic telegraph cable. This
was both insulated and coated with gutta percha.
Gutta percha is
very stable underwater and the cables lasted many
years - it would not surprise me if some still
existed today although modern ones are plastic
insulated and coated. Indeed, Gutta percha is
very difficult to find today in anything other
than antiques. A recent television programme
about the history of golf found its researchers
scouring the country to find some virgin material.
One small sealed tin was eventually found in
Hertfordshire and, when opened, it revealed a
slab of pale cream pure gutta percha which had
not seen the light of day for many decades. After
filming the tin was re-sealed for posterity.
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