IMPROVE- MENTS IN TReating MateRIALS FOR THE MANUFACTURE OF PAINT
Year: 1880

page_text: LETTERS PATENT to John Cowdery Martin, of the Whitelead Works, Macks
Road, Bermondsey, in the County of Surrey, for an Invention of "IMPROVE-
MENTS IN TReating MateRIALS FOR THE MANUFACTURE OF PAINT."
PROVISIONAL SPECIFICATION left by the said John Cowdery Martin at
the Office of the Commissioners of Patents on the 31st March 1880.
JOHN COWDERY MARTIN, of the White Lead Works, Macks Road, Bermondsey,
in the County of Surrey. "IMPROVEMENTS IN TREATING MATERIALS FOR THE
MANUFACTURE OF PAINT."
My Invention consists in treating the various materials or pigments previous to
their being ground with oil, for the purpose of increasing the body of the resulting
paint, by thouroughly incorporating or grinding them while they are either in
combination with water, or in a dry condition, with a small quantity of silica in
hydrated state, either alone or combined with other substances, such as form stcatite
or soapstone, tale, asbestos, or other similar material containing fixed water or water
of hydration.
I mix the several ingredients together when they are in a wet condition
and grind them together when dry previous to their being incorporated with
the oil.
Zinc white, sulphate of baryta, white lead, and other pigments or materials used
for the manufacture of paint may be so treated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Cowdery Martin in the Great Seal Patent Office on the 29th
September 1880.
JOHN COWDERY MARTIN, of the White Lead Works, Macks Road, Bermondsey,
in the County of Surrey. "IMPROVEMENTS IN TREATING MATERIALS FOR THE
MANUFACTURE OF PAINT."
My Invention consists in treating the various materials or pigments for the
purpose of increasing the body of the resulting paint, by thouroughly incorporating
or grinding them while they are either in combination with water, or in a dry
condition, with a small quantity of silica in a hydrated state, either alone or
combined with other substances, such as form steatito or soapstone, tale, asbestos, or
other similar material containing fixed water or water of hydration.
I mix the several ingredients together when they are in a wet condition, and
grind them together when dry, previous to their being incorporated with the oil. Zinc
white, sulphate of baryta, white lead, and other pigments or materials used for the
manufacture of paint may be so treated. Pigments or colours largely composed of
sulphate of baryta, as some varieties of Brunswick green & chrome yellow, and
most materials which are deficient in body are improved in spreading & covering
qualities.
The specific gravity of oxido of zinc is increased, it is much improved in body
and in spreading and covering properties, and will grind into paint with far less oil
than is usually required.
I prepare the hydrated silica by precipitating it from a solution of an alkaline
silicate by means of an acid, and by afterwards slowly drying it. In place of the
precipitated hydrated silica I use steatite, a mineral substance chiefly composed of
hydrated silica and magnesia, and for convenience I prefer this substance; or I use
talc or asbestos or other minerals of a like kind or composition, and which are
largely composed of hydrated silicate of magnesia, all being reduced as nearly as
possible to an impalpable powder. I add the hydrated silica or hydrated silicate
of magnesia to the various pigments or materials while these are in process of
manufacture, and in combination with water, or I mix them together after drying,
in both cases grinding or crushing the materials together in a dry condition by
means of edge runner stones or other suitable grinding or crushing apparatus,
I find a quantity of the hydrated silica or hydrated silicate of magnesia equal to
from seven to ten per cent. by weight of the other pigments or materials used and
ground or incorporated with them gives good results. After such treatment of tho
materials they may be mixed or ground with oil to form paint in the usual
manner.
Having now described the nature of my said Invention, and the manner in
which the same is to or may be performed, I would have it understood that what I
claim is, treating materials for the manufacture of paint by mixing or grinding them
with hydrated silica or hydrated silicato of magnesia as described for the purpose
of increasing their specific gravity or their body and covering propertics as
paint.
In witness whereof, I, the said John Cowdery Martin, have hereunto set
my hand and seal, this Twenty ninth day of September, in the year of our