A Process for Bleaching Ground Cork.
Year: 1890

page_text: Date of Application, 19th Sept., 1890
Complete Specification Left, 11th June, 1891-Accepted, 11th July, 1891
PROVISIONAL SPECIFICATION.
A Process for Bleaching Ground Cork.
I, FREDERICK WALTON, of No. 4 Portugal Street, Lincolns Inn Fields, in the
County of London, Manufacturer, do hereby declare the nature of this invention to
be as follows
The ground cork employed in the manufacture of linoleum and like products is
usually so discoloured that it is very difficult to get in those products the purity of
tints desirable for ornamental patterns.
This invention relates to a process for bleaching ground cork, removing from it
the colour which it usually possesses, and reducing it to a white, which is susceptible
of any desired tint by dyeing or otherwise colouring. For this purpose I proceed
as follows:
I charge a vat with water acidulated with 5 to 10 per cent. of nitric acid; into
this I blow steam by a leaden pipe, and, when the liquid is boiling, I introduce
ground cork by successive doses, keeping the whole well stirred. The cork, having
the air expelled from it, sinks at first, but after a time the whole mass begins to
rise, whereupon the steam is shut off and the contents of the vat are somewhat
cooled by addition of cold water. The cork again sinks, and then I turn on the
steam again and keep the contents of the vat well stirred and boiling for about half
an hour. After a little cooling, I strain off the liquid and thoroughly wash the
cork with water forced through it by a centrifugal machine or vacuum pump or
otherwise.
The washed cork is then treated with chloride of lime and sulphuric acid in the
same manner as in the bleaching of paper pulp. After again straining and washing,
the cork may be pressed to get rid of a proportion of adhering water, and is then
dried for use.
Dated this 19th day of Sentember 1800.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
A Process for Bleaching Ground Cork.
I, FREDERICK WALTON of No. 4 Portugal Street, Lincolns Inn Fields, in the
County of London, 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 :-
The ground cork employed in the manufacture of linoleum and like products is
usually so discoloured, that it is very difficult to get in those products the purity of
tints desirable for ornamental patterns. This invention relates to a process for
bleaching ground cork, removing from it the colour which it usually possesses and
reducing it to a white, which is susceptible of any desired tint by dyeing or other-
wise colouring. For this purpose I proceed as follows.
I charge a vat with water acidulated with 5 to 10 per cent. of nitric acid, into
this I blow steam by a leaden pipe, and when the liquid is boiling I introduce
ground cork by successive doses, keeping the whole well stirred which may be done
by a revolving agitator. The cork having the air expelled from it, sinks at first
but after a time the whole mass begins to rise, whereupon the steam is shut off and
the contents of the vat are somewhat cooled by addition of cold water.
The cork again sinks, and then I turn on the steam again and keep the contents
· Prine sl

page_text: of the vat well stirred and boiling for about half an hour. After a little cooling
I strain off the liquid and thoroughly wash the cork with water which may be
forced through it by a centrifugal machine or vacuum pump or otherwise.
The washed cork is then treated with chloride of lime and sulphuric acid in the
same manner as for the bleaching of paper pulp. After again straining and washing,
the cork may be pressed to get rid of a proportion of adhering water, and is then
dried for use.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I claim :-
The herein described process for bleaching ground cork by subjecting it to
steaming and agitation in acidulated water, straining and washing, treating with
chloride of lime and sulphuric acid, again straining and washing and finally
drying.
Dated this 11th day of June 1801
ABEL & IMRAY,
Agents for the Applicant.