In
1887,
John
Boyd
DUNLOP
(1840
–1921),
born
in
Scotland,
developed
the
first
practical
pneumatic
or
inflatable
tire
for
his
son's
tricycle,
tested
it
and
patented
it
on
December
7,
1888.
Even
two
years
later
his
patent
becomes
officially
invalid
because
the
Scottish
inventor
Robert
William
Thomson
(1822
-
1873)
had
patented
the
same
idea
already
in
GB,
France
(1846)
and
in
the
US
(1847),
DUNLOP
from
now
on
was
the
eponym
for
this
vulcanization
process.
In
1928
DUNLOP
technicians
in
Hanau
(Germany)
established
the
first
standardized
method
for
foaming
latex.
Other
sources
claims
that
the
first
latex
foam
mattress
was
produced
1929 at DUNLOPILLO in Great Britain.
This
“DUNLOP
process”
for
vulcanizing
latex
foam
for
mattresses
and
pillows
did
not
change
significantly
since
these
early
days.
Some
chemicals
has
been
replaced
cause
of
small
developments
but
the
fundamental
chemical
process,
the
cross-linking
of
rubber
molecules
with sulphur, is still the same.
In
short
the
latex
compound
is
mixed
up
(foamed)
with
air,
transferred
into
a
metal
mould
(made
of
steel
and/or
aluminium)
with
hundred
of
pins
and
heated
(vulcanized)
in
a
steam
chamber or tunnel.
The
distances
between
the
pins
and
their
numbers
are
defined
by
the
fact
of
the
slow
heat
transfer
which
is
an
indirect
one:
The
saturated
steam
in
the
vulcanizing
chamber
initially
transfers
the
heat
to
the
surface
of
the
mould
and
from
there
the
energy
is
moving
slowly
inside
the
foam
through
the
pins
until
the
foam
inside
is
reaching
the
required
vulcanizing
temperature of about 100°C.
Looking
deeper
into
the
facts
for
a
US
Queen
Size mattress with 60 in × 80 inch:
The
dry
volume
of
such
a
mattress
(pins
are
not
taken
into
consideration
here)
is
about
460
litres.
At
an
average
density
of
130
grams
per
litre
(wet
foam)
the
weight
of
latex
is
ab.
60
kg
only.
The
rest
(400
litres)
is
simply
air
which
unfortunately
is
working
as
an
insulator
and
poorly
heatable.
For
such
a
mattress
core
a
vulcanization
time
up
to
one
hour
is
not
uncommon.
The
weight
of
such
a
metal
mould
could
sum
up
to
1.200
kg!
Thus
more
than
one
ton
of
metal
is
heated
up
to
vulcanize
just
only
60
kg
of
wet
latex
foam
and
it
is
obvious
that
such
a
production
system
needs
a
very
heavy
support
structure.
Also
it
is
evidently
that
such
a
system
is
inflexible
and
slow
in
regards
in
general
handling
like
mould
opening,
closing
and
exchange.
Now
you
may
want
to
know
what‘s
different
in
my
process ?
Please read more at
TECHNOLOGY
Natural
latex
is
the
“liquid
milk”
tapped
from
the
rubber
tree
Hevea
Brasiliensis.
Its
main
cultivation
areas
in
Asia
are
responsible
for
more
then
90%
of
the
world
natural
rubber
production
of
12.314
thousand
metric
tons
(2015)
of
which
liquid
latex
has
only
a
small
share
of
about
10%.
After
gathering
the
liquid
latex
in
the
plantations
it
is
concentrated
and
preserved
with
some
ammonia
and
TMTD/ZnO.
This
standardized
LA-latex
(low-ammonia
latex)
is
the
basis
for
dipping
products
such
as
condoms,
balloons
and
gloves
but
also
for
latex
foam
goods
such
as mattress cores and pillows.