Process of Treating Flax Straw for Obtaining Textile Fibres therefrom.
Year: 1899

page_text: Date of Application, 18th Feb., 1899
Complete Specification Left, 20th Nov., 1899-Accepted, 23rd Dec., 1899
PROVISIONAL SPECIFICATION.
Process of Treating Flax Straw for Obtaining Textile Fibres
therefrom.
I, CILARLES WETHERWAX, of 15, Bath Street, Leith, North Britain, Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
My invention relates to a process of retting flax straw for the purpose of
obtaining textile fibres therefrom, the special advantages of the process over the
ordinary slow method of water or dew retting being its rapidity and the avoid-
ance of the objections incidental to the old method and in particular that of the
staining of the fibres by fermentation and the impairing of the strength of the
fibres by the subsequent treatment necessary for the removal of the stain. By
this improved process the colouring matter is removed in the initial stages of
treatment of the straw and a remarkably white flax is produced which requires
very little subsequent bleaching and very little, if any, boiling in alkali after
being spun into yarn or thread, to effect the removal of the resins, the ultimate
product of the improved method being a flax of remarkably good colour and silky
appearance possessing all the natural strength of the fibres. Other advantages
incidental to the new process are the softening, dissolving, and washing away
of the pulpy particles leaving the lint and shive (or woody matter) ready for
breaking and scutching the ease with which the shive is detached from the fibres
when dried and scutched; and the facility which the process affords for drying
and stacking the flax for treatment at any time of the year.
The process of my invention consists essentially in subjecting the flax straw
to treatment by first boiling the same in an alkaline solution composed of soda
ash or caustic soda and water and of an emulsion produced as hereafter described
and after washing the straw with water, treating it with an acid solution and
again washing it.
The solution in which the straw is first boiled contains per gallon of water
about one ounce soda ash or caustic soda together with half an ounce of the
emulsion hereafter described.
The emulsion above referred to is produced as follows:-I dissolve 20 lbs.
of caustic soda in 8 gallons of water and cool the solution to a temperature of
80° Fahrenheit. I also melt 130 lbs. of tallow or fat free from salt and bring
it to a temperature of 120° Fahrenheit. I then pour the caustic soda solution
slowly into the melted fat, stirring until the two ingredients are thoroughly
I then let it stand for about
incorporated and the mixture becomes smooth.
24 hours or until saponification ensues, after which it is re-melted with an
aridition of 100 lbs. of fat and when thoroughly melted I add 30 gallons of water
and mix thoroughly by stirring and then boiling the emulsion.
The preliminary operation of boiling the flax straw in the alkaline solution
of soda ash or caustic soda and emulsion is continued for from thirty to sixty
minutes according as it is performed under steam pressure of, say, 50 lbs. per
square inch or under atmospheric pressure. The boiling may be performed in any
suitable apparatus but if the operation be performed under steam pressure it will

page_text: be convenient to employ a digester to contain the straw and a circulating appa-
ratus by which a circulation of the treating solutions is maintained through the
digester in the upward direction.
The digester consists merely of a closed cylinder preferably vertical with the
two ends of which are connected inflow and outflow circulating pipes for the solution,
the circulation of the solution being maintained in the upward direction through
the digester by a centrifugal or other pump interposed in the circuit of the pipe,
part of which pipe is in the form of a coil and is contained within a steam drum
connected with a steam generator for the purpose of maintaining the solution at
the temperature necessary to produce the required steam pressure and heat in the
digester.
The flax straw without being bent or broken is stacked in the form of
bundles with the straw in the vertical direction for which purpose the bundles
are placed on end tier above tier in an inner rack or cage having a perforated
bottom so as to permit the free circulation of liquid whilst allowing the bundles
to be easily introduced and removed. The washing of the flax would also be
performed in the digester (connection of the digester with the circulation pipes
and pump being shut off) a hydrant being connected to the bottom of the digester
so that clean water enters at bottom and is discharged at top along with the dirt
and impurities.
The
After washing, the subsequent treatment of the flax straw in the acid solution
is continued for about twenty minutes (more or less) the strength of the solution
being about six ounces sulphurous acid (H, S 03) or a quarter ounce sulphuric
acid (vitriol) or a quarter ounce hydrochloric acid, per gallon of water.
reaction produced by this acidulation following on the alkaline treatment has the
effect of causing a partial bleaching of the fibre and assists the solution of the
gummy matters and vegetable juices contained in the straw. After the treat-
ment with the acid solution the straw is again washed.
By causing the solutions and washing water to circulate in the upward direction
through the digester the packing of the straw tightly by gravitation and pressure
of steam above the solution in the top of the digester is prevented, the straw
being on the contrary held in suspension and loosened by its tendency to float
in the liquid which is thus circulated more thoroughly and uniformly throughout
the mass, whilst in the case of the washing water the dirt and dissolved vegetable
matter rise and are carried off by the water.
Dated this 18th day of February 1800
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
Process of Treating Flax Straw for Obtaining Textile Fibres
therefrom.
I, CHARLES WETHERWAX, of 15, Bath Street, Leith, North Britain, Manu-
facturer, 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:-
My invention relates to a process of retting flax straw for the purpose of
obtaining textile fibres therefrom, the special advantages of the process over the
ordinary slow method of water or dew retting being its rapidity and the avoid-
ance of the objections incidental to the old method and in particular that of the

page_text: staining of the fibres by fermentation and the impairing of the strength of the
fibres by the subsequent treatment necessary for the removal of the stain. By
this improved process the colouring matter is removed in the initial stages of
treatment of the straw and a remarkably white flax is produced which requires
very little subsequent bleaching and very little, if any, boiling in alkali after
being spun into yarn or thread, to effect the removal of the resins, the ultimate
product of the improved method being a flax of remarkably good colour and silky
appearance possessing all the natural strength of the fibres. Other advantages
incidental to the new process are the softening, dissolving, and washing away
of the pulpy particles leaving the lint and shive (or woody matter) ready for
breaking and scutching; the ease with which the shive is detached from the fibres
when dried and scutched; and the facility which the process affords for drying
and stacking the flax for treatment at any time of the year.
The process of my invention consists essentially in subjecting the flax straw
to treatment by first boiling the same in an alkaline solution composed of soda
ash or caustic soda and water and of an emulsion produced as hereafter described
and after washing the straw with water, treating it with an acid solution and
again washing it.
The solution in which the straw is first boiled contains per gallon of water
about one ounce soda ash or caustic soda together with half an ounce of the
emulsion hereafter described.
The emulsion above referred to is produced as follows:-I dissolve 20 lbs.
of caustic soda in 8 gallons of water and cool the solution to a temperature of
80° Fahrenheit. I also melt 130 lbs of tallow or fat free from salt and bring
it to a temperature of 120° Fahrenheit. I then pour the caustic soda solution
slowly into the melted fat, stirring until the two ingredients are thoroughly
incorporated and the mixture becomes smooth. I then let it stand for about
24 hours, or until saponification ensues after which it is re-melted with an
addition of 100 lbs. of fat, and when thoroughly melted I add 30 gallons of water
and mix thoroughly by stirring and then boiling the emulsion.
The preliminary operation of boiling the flax straw in the alkaline solution
of soda ash or caustic soda and emulsion is continued for from thirty to sixty
minutes according as it is performed under steam pressure of, say, 50 lbs. per
square inch or under atmospheric pressure. The boiling may be performed in any
suitable apparatus but if the operation be performed under steam pressure it will
be convenient to employ a digester to contain the straw and a circulating appa-
ratus by which a circulation of the treating solutions is maintained through the
digester in the upward direction.
The digester consists merely of a closed cylinder preferably vertical with the
two ends of which are connected inflow and outflow circulation pipes for the solution,
the circulation of the solution being maintained in the upward direction through
the digester by a centrifugal or other pump interposed in the circuit of the pipe,
part of which pipe is in the form of a coil and is contained within a steam drum
connected with a steam generator for the purpose of maintaining the solution at
the temperature necessary to produce the required steam pressure and heat in the
digester. The flax straw, without being bent or broken, is stacked in the form of
bundles with the straw in the vertical direction, for which purpose the bundles
are placed on end tier above tier in an inner rack or cage having a perforated
bottom so as to permit the free circulation of liquid whilst allowing the bundles
to be easily introduced and removed. The washing of the flax would also be
performed in the digester (connection of the digester with the circulation pipes
and pump being shut off) a hydrant being connected to the bottom of the digester
so that clean water enters at bottom and is discharged at top along with the dirt
and impurities.
After washing, the subsequent treatment of the flax straw in the acid solution
is continued for about twenty minutes (more or less) the strength of the solution
being about six ounces sulphurous acid (H₂ S O₂) or a quarter ounce sulphuric

page_text: The
acid (vitriol) or a quarter ounce hydrochloric acid, per gallon of water.
reaction produced by this acidulation following on the alkaline treatment has the
effect of causing a partial bleaching of the fibre and assists the solution of the
gummy matters and vegetable juices contained in the straw.
After the treatment with the acid solution the straw is again washed.
By causing the solutions and washing water to circulate in the upward direction
through the digester the packing of the straw tightly by gravitation and pressure
of steam above the solution in the top. of the digester is prevented, the straw
being on the contrary held in suspension and loosened by its tendency to float
in the liquid which is thus circulated more thoroughly and uniformly throughout
the mass, whilst in the case of the washing water the dirt and dissolved vegetable
matter rise and are carried off by the water.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. The herein described method of retting flax which consists essentially in
boiling the flax straw, either under steam pressure or not, in a solution contain-
ing soda ash or caustic soda and an emulsion prepared as herein specified and after
washing, treating the straw with an acid solution as herein specified.
2. In the herein described method of retting flax by first subjecting it to
alkaline treatment as described, the method of acidulation after alkaline treat-
ment whereby to produce a reaction causing a partial bleaching of the fibre. and
a further dissolution of the gummy and vegetable juices and matters contained
in the straw.
Doted this 18th day of November 1899.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.