Improvements in Distempers or Colour Washes.
Year: 1896

page_text: Date of Application, 10th Dec., 1896-4ccepted, 16th Jan., 1897
COMPLETE SPECIFICATION.
Improvements in Distempers or Colour Washes.
I, WILLIAM AUGUSTUS HALL, resiling on Westminster Street, in the City of
Bellows Falls, County of Windham, State of Vermont, United States of America,
Manufacturer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to improvements in water-paints, particularly that class
in which the component parts are thoroughly commingled and put up in dry powder
form in readiness for subsequent use by the addition of water.
This class of paints comprises generally a base of some earthy or mineral
compound with an adhesive. My invention is embodied in the nature, as likewise
in the treatment of the adhesive, whereby said adhesive is first rendered soluble
and, after being mixed with water and applied to the surface upon which it is
to be placed, is then oxydized by exposure to the air and becomes insoluble. In.
this way I am enabled to make a waterproof paint; one that possesses the
characteristics of an oil paint in that it can be washed and withstand rain and
exposure to the weather."
In the composition of this water paint I propose to manufacture it as a white,
dry powder, and to this end the base is composed preferably of silicate of
magnesia or talc, and the adhesive, in the proportion of ninety (90) per cent. base
and ten (10) per cent. adhesive. In lieu, however, of a single base, other ingredients
may be added and I find that whiting may be employed with good results; when
this substance is used the base then consists preferably of fifty (50) per cent. of the
tale and forty (40) per cent. of the whiting, with ten (10) per cent. of the adhesive
but these proportions may be varied according to the situation or the exposure to
which the paint is to be subjected.
The adhesive is to be made from casein and lime. Casein is an organic glutinous
substance obtained from milk, or skimmed milk, and is produced by coagulating
milk, with an acid. Under my invention I propose to heat the milk to
100 degrees Fahrenheit, then add the acid; when the curd is thrown down, the
whey is drained off and the curd then rinsed or washed after that it is crumbled
and drained out. This casein after evaporation and when reduced to powder, is
almost a pure white substance, not granular, but very fluffy and preferably employed
in this form to enable a more intimate mixture with the lime because if the particles
are in any way coarse the lime alkali is very slow in dissolving it. On the contrary
it may be remarked that casein in its natural state is an amber colored granular
substance.
In the preparation and manufacture of this adhesive, I take about sixty
(60) per cent. of dry casein, and mix it with about forty (40) per cent. of good
dry slaked powdered lime. By experiment I have found that the lime which
I employ is now used in any sense as a base, but merely to render the casein soluble
in water. That is, the casein without being treated with lime or other alkali, is
ordinarily insoluble either in hot or cold water but by means of the lime I produce
a chemical reaction that results in a substance which in the presence of an alkali
is not only soluble in water, but after application to the surface on which it is laid
becomes insoluble due to oxydization.

page_text: Now I find that any alkali will render the casein soluble, but lime from calcium
or magnesia, the latter commonly known as dolomite, alone appears to enter into
a chemical combination to form an insoluble compound upon oxydization. With
the other alkalis the casein is rendered soluble by treatment with said alkali, but
when exposed to the air after being mixed with water, still remains soluble and
consequently fails in the necessary results, that of being waterproof. With the
above proportions of the base composed of fifty (50) per cent. of tale and forty
(40) per cent. of whiting, I add about ten (10) per cent. of the adhesive. Owing to
the action of the lime on the casein, a waterproof paint is formed; furthermore no
antiseptic or other analogous materials are necessary to prevent it from decomposing
or from smelling when decomposed.
This composition of matter, when manufactured, is a white dry powder, which is
made into paint by mixing it with cold water. The above mentioned ingredients,
when compounded, produce a very smooth, fine, white paint which may be colored
if so desired. This paint spreads very easily and smoothly, has no color, and when
dry becomes extremely hard and quite waterproof.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1st. A water paint, composed of a mineral compound in powdered form, as a base,
and an adhesive to form an insoluble compound by oxydization, consisting of casein,
and lime in the proportions, substantially as specified.
2nd. A dry powder in the proportions substantially as set forth, comprising
talc as a base, an adhesive formed of casein as specified, and a lime of calcium or
magnesia.
. 3rd. A water paint cousisting of a mineral compound in powdered form as a base,
an adhesive composed of casein and oxide of calcium, and water in the proportions,
substantially as stated.
Dated this Twenty-sixth day of November 1896.
WILLIAM AUGUSTUS HALL.