CASEIN
Casein, the
protein in milk was used by the Ancient Egyptians
as a fixative for pigments in wall paintings. It
has also been used as a constituent in various
glues but it appears not to have been used as the
basis of a solid plastics material until the end
of the 19th century. Krisch, head of a large firm
of printers in Hanover experimented with casein
to make a washable white board for replacing the
slates used in school - paper was too expensive
at that time for use by children to practise
writing. He collaborated with Adolf Spitteler, a
chemist in Bavaria and on July 15th 1899, a
patent for "plastic compositions" was
taken out in Germany.
The patent was
taken up by firms in Germany (Vereinigten
Gummivarenfabriken, at its factory in Harburg)
and in France by Pellerin and Orosdi (Compagnie
Francaise de la Galalithe, at Levallois Perret).
The product was introduced under the trade name
Galalith and was first shown at the Paris
Universal Exhibition in 1900. A lot of
development work was still required to produce a
stable material, and the two companies merged in
1904 to form the International Galalith
Gesellschaft Hoff and Company with a new factory
in Harburg. A process starting with dried casein
granules, known as the dry process, was developed
and this was to become the universally adopted
method for casein plastics manufacture and
remained virtually unchanged throughout its
history.
In Britain, a wet
process starting with milk curds was patented in
1909 by a Russian student, Victor Schutze, from
Riga. This material was called Syrolit and a
factory of the same name was set up in a disused
cloth mill at Stroud in Gloucestershire. However,
it was not successful and by 1913 the company was
bankrupt. A new company, was established at the
same premises to manufacture casein using the dry
process. The new product was called Erinoid and
this was also adopted as the name of the company.
Production commenced in 1914 and as supplies of
Galalith were cut off at the commencement of
World War I, the material found a ready market
and button manufacturers from Birmingham were
waiting on the doorstep for the first
consignments. Lactoid, made by BX Plastics was
introduced in 1922 at their Larkswood Factory in
Higham Station Avenue, London. Young & Wolf
Ltd. had a small production unit located at
Bridgend Works, Stonehouse in Gloucestershire -
they manufactured mainly rod, button blanks and
knitting needles from about 1930.Young and Wolf
pioneered the slicing of casein button blanks
from rod in the UK.Charles Horner Ltd. of Halifax,
England. like Young & Wolf, also produced
casein plastics mainly in the form of knitting
needles, button blanks and rod. Their brand name
was Dorcasine.
These four British
manufacturers formed the Casein Plastics
Association (until 1938 it was called the
Artificial Horn Manufacturers Association). At
the commencement of World War II supplies of raw
casein granules were no longer obtainable from
Europe, the traditional source, and the CPA were
encouraged by the British Government to seek
alternative supplies in order to make buttons for
military use. Argentina provided this need. In
1944, the CPA co-operated with The Knitting Pin
Association and the Casein Button Manufacturers
Association to form The Casein Plastics Joint
Development Association, to represent the
interests of both manufacturers and users of
casein plastics. Perhaps the greatest
contribution of the CPA was in the 1950s to
improve the process for manufacturing casein
granules. With the co-operation of the New
Zealand and Norwegian dairies, this resulted in a
casein of improved quality with a better base
colour thus increasing the colour range,
especially of very pale colours.
Erinoid remained the major producer of casein
plastics in the UK until they stopped manufacture
in about 1980. At that time they were part of
British Petroleum. There were negotiations in
hand for the sale of the casein business which
was still profitable, but unfortunately these
broke down. BX Plastics had already closed their
Lactoid business in 1962 and all other British
casein firms had also ceased production.
In the United
States, casein plastics material was introduced
by Christensen about 1919 and sold under the name
Aladdinite. In 1924, Karolith was produced
followed by Erinoid by a subsidiary of the
British company. Casein did not achieve the same
success in the US as it did in Europe - partly
due to greater competition from cast phenolic
resins, also some European applications were
excluded because of the climatic conditions.
Starting in about 1928 many casein manufacturing
plants joined forces with button manufacturers to
make casein directly into buttons. This included
button manufacturer George Morrell who took over
Kyloid, and Aladdinite who joined the Button
Corporation of America. In 1931 Karolith
Corporation, Erinoid Company of America, American
Machine & Foundry Company and Pan plastics
Corporation merged their casein interests to form
the American Plastics Corporation to produce
casein under the name Ameroid.
The first Russian
factory for artificial horn was started up in1928
at Mnewniki, near Moscow.
Properties and
Use
Casein has been
described as "the most beautiful of plastics"
and was produced in a wide variety of colours
including delicate pastel shades, pearls and
mottles, especially those imitating tortoiseshell
and horn. The material also readily takes a
surface dye and this process was extensively used
to produce fashionable colours at short notice
and for two colour effects by selectively cutting
back the dyed surface layer. Casein plastics take
an attractive polish which can be achieved
mechanically with abrasives (except for surface-dyed
material) or chemically by immersion in hot,
hypochlorite solution - known as dip polish.
Casein plastics are most frequently encountered
in the form of buttons, buckles and knitting
needles but it was also used for fountain pens,
propelling pencils, dress ornaments, knife
handles, necklaces, dressing table ware, manicure
sets and a wide variety of items generally
referred to as "fancy goods". It also
found limited use for low voltage electrical
plugs, sockets or jacks, mainly red or black, in
the 1920s and 30s and sometimes as components of
early telephones.
The manufacture of
casein is a slow, batch process requiring the
material finally to be hardened by immersion in
formaldehyde solution - sections of about 25mm
thickness requiring up to one year. Casein
plastics are not readily moulded, although sheet
can be pressed into a limited range of shapes,
such as shallow bowls and candlestick bases, by 'hot
stamping' . Instead, casein objects are
fabricated from stock material such as sheet, rod
or tube. Button blanks were stamped from sheet or
sliced from rod but in the early years most were
trepanned from sheet material.
As a button
material it is resistant to washing, dry cleaning
and can withstand momentary contact with a hot
iron - unlike most other competitive early
plastics materials, but with the advent of the
newer plastics after 1945 its use gradually
declined. However, limited quantities of casein
plastics are still produced in some countries
with large dairy interests, for example New
Zealand, but specialised buttons are probably the
only casein items manufactured today.
|