Improvements in the Treatment of Raw Silk and Mixed Silk and Cotton Goods.
Year: 1899

page_text: Date of Application, 13th Mar., 1899
Complete Specification Left, 24th Nov., 1899-Accepted, 17th Feb., 1900
PROVISIONAL SPECIFICATION.
* Improvements in the Treatment of Raw Silk and Mixed Silk and
Cotton Goods.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Badische Anilin & Soda Fabrik of
Ludwigshafen-on-Rhine, in the German Empire) to be as follows:-
Caustic alkali solutions act on raw silk, as is known, in such a manner, that
the silk gum is first dissolved, and then the silk fibre itself is attached. In conse-
quence of the difficulty of limiting the action to the silk gum alone, caustic
alkalies have not hitherto been capable of being employed in practice under
the usual conditions for removing the gum from raw silk. A weak alkaline
body like soap serves this purpose, the method generally used being to boil
the silk with the soap solution for one or two hours.
My foreign correspondents have discovered that the presence of glucose so
influences the action of caustic alkalies on raw silk that the destruction of
the silk fibre is greatly retarded, while the dissolution of the silk gum is not
hindered. By means of a mixture of caustic lye and glucose, the complete re-
moval of the gum, or bast, from the silk can be effected without injury to the
structure, gloss and strength of the fibre.
This process has the advantage over the old method of being performed at
ordinary temperature and of taking but little time, but the so-called "boiled
off liquor," a valuable bye-product used by silk-dyers, is not obtained.
When this bye-product is desired, the new process can be employed in com-
bination with the old method. My foreign correspondents have discovered that
by using the glucose and alkali in a solution of suitable concentration the
action can be so regulated that the silk-gum is not removed from, but only
loosened on the fibre, so that a subsequent treatment, for from five to ten
minutes, with a hot soap solution suffices to effect a perfect removal thereof,
and at the same time the "boiled-off liquor is obtained.
In the case of "half silk" (that is, a material made of cotton and silk) the
circumstances are different. The new process presents special advantages here
for the reason that a double action takes place, namely, the removal of the
silk gum, or bast, and simultaneously the mercerisation of the cotton, without
any noticeable shrinking thereof.
Thus in the case of half silk the addition of the glucose appears to effect
not only the protection of the silk fibre from the injurious action of the alkali
but at the same time to hinder the great shrinking that occurs during the
treatment of cotton and half silk fabrics with caustic lyes alone.
As is well known, the affinity of cotton fibre for dyes is much increased by
mercerisation, so that a material made of silk and mercerised cotton possesses
the great advantage that the necessary covering of the cotton with colour takes
place far more easily and perfectly than is the case with half silk which contains
cotton that has not been mercerized.

page_text: A method for effecting the removal of the gum, or bast, and mercerisation
of half silk on the jigger (that is without tension) in one operation has not
hitherto been known. To make the valuable properties of mercerised cotton
available for half silk, the cotton had either to be mercerised before the pre-
liminary weaving, or after the same, with the simultaneous employement of
tension during which the action of the alkali on the silk gave rise to the bad
effects previously mentioned.
The following example of a method of applying the new process to half-silk
goods will serve to further illustrate the nature of the invention.
The half-silk, that has previously been damped with hot water, is passed
through a bath which is contained in a jigger such as is commonly employed in
the silk industry, the said bath being made as.. follows:
700 parts (by weight) of caustic soda lye containing 35 per cent. NaOH,
200 parts of water, and 300 parts of glucose, are mixed together, care being
taken that the mixture does not become too hot.
The removal of the silk-gum, or bast, and mercerisation of the cotton is
completed in from five to ten minutes at the usual temperature. The after-
treatment is the same as for soap boiled material.
If desired, the material can first be impregnated with the glucose and then
treated with the caustic soda.
Dated this Bth day of March 1809
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C.. Agents.
COMPLETE SPECIFICATION.
Improvements in the Treatment of Raw Silk and Mixed Silk and
Cotton Goods.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Badische Anilin & Soda Fabrik of
Ludwigshafen-on-Rhine, in the German Empire) and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement:-
Caustic alkali solutions act on raw silk, as is known in such a manner that
the silk gum is first dissolved, and then the silk fibre itself is attacked. In conse-
quence of the difficulty of limiting the action to the silk gum alone, no process
has been available by which caustic alkalies could be employed generally in
practice under the usual conditions for removing the gum from raw silk. A
weak alkaline body like soap has, as a rule, to be taken and the method generally
used is to boil the silk with the soap solution for one or two hours.
My foreign correspondents have discovered that the presence of glucose or
glycerine so influences the action of caustic alkalies on raw silk that the destruc-
tion of the silk fibre is greatly retarded, while the dissolution of the silk gum
is. not hindered. By means of a mixture of caustic lye and glucose or glycerine,
the complete removal of the gum, or hast, from the silk can be effected without
injury to the structure, gloss and strength of the fibre.
This process has the advantage over the old method of being performed at
ordinary temperature and of taking but little time, but the so-called "boiled-
off liquor," a valuable bye-product used by silk-dyers, is not obtained.
When this bye-product is desired, the new process can be employed in com-

page_text: bination with the old method. My foreign correspondents have discovered that
by using the glucose or glycerine and alkali in a solution of suitable concentration
the action can be so regulated that the silk gum is not removed from, but only
loosened on the fibre, so that a subsequent treatment, for from five to ten
minutes, with a hot soap solution suffices to effect a perfect removal thereof,
and at the same time the "boiled-off liquor" is obtained.
This can be illustrated by the following example.
Thoroughly wet the silk to be freed from bast with warm water, press it to
get rid of the excess of water, and then enter the damp silk into a bath made
up as follows: sixty five parts of caustic soda lye (containing about thirty five
per cent. NaOH), forty parts of glucose, and eight hundred and ninety five parts
of water. Prepare this bath by mixing together the caustic soda and the glucose
in solution in water and taking care that excessive heat does not take place on
mixing. The silk is treated in this bath at a temperature of about twenty degrees
Centigrade for from two to four minutes, then quickly swill the silk well with
cold water, and subsequently boil in a soap solution for a short time. The silk
is quickly freed from bast and the boiled-off liquor is obtained.
The removal of the bast can be effected by the use of more strongly alkaline
solutions such, for instance, as that described in the example hereinafter given
but when using such solutions the boiled-off liquor is not obtained.
In the case of "half silk" (that is, a material made of cotton and silk) the
circumstances are different. The new process presents special advantages here
for the reason that a double action takes place, namely, the removal of the
silk gum, or bast and simultaneously the mercerisation of the cotton, without
any noticeable shrinking thereof.
Thus in the case of "half silk" the addition of the glucose or glycerine
appears to effect not only the protection of the silk fibre from the injurious
action of the alkali but at the same time to hinder the great shrinking that
occurs during the treatment of cotton and half silk fabrics with caustic lyes
alone.
As is well known, the affinity of cotton fibre for dyes is much increased by
mercerisation, so that a material made of silk and mercerised cotton possesses
the great advantage that the necessary covering of the cotton with colour takes
place far more easily and perfectly than is the case with half silk which con-
tains cotton that has not been mercerised.
A method for effecting the removal of the gum, or bast, and mercerisation of
half silk on the jigger (that is without tension) in one operation has not hitherto
been known. To make the valuable properties of mercerised cotton available
for half silk, the cotton had either to be mercerised before the preliminary
weaving, or after the same, with the simultaneous employment of tension during
which the action of the alkali on the silk gave rise to the bad effects previously
mentioned.
The following example of a method of applying the new process to half silk
goods will serve to further illustrate the nature of the invention and the manner
in which it can be carried into practical effect.
The half silk, that has previously been damped with hot water, is passed
through a bath which is contained in a jigger such as is commonly employed
in the silk industry, the said bath being made as follows:-
Seven hundred parts (by weight) of caustic soda lye containing thirty five
per cent. NaOH two hundred parts of water, and three hundred parts of glucose
or glycerine, are mixed together, care being taken that the mixture does not
become too hot.
The removal of the silk gum, or bast, and mercerisation of the cotton is com-
pleted in from five to ten minutes without the application of heat. The after
treatment is the same as for soap boiled material.
If desired, the material can be first impregnated with the glucose and then
treated with the caustic soda.

page_text: I do not claim the use of a mixture of caustic alkali and glycerine or glucose
for mercerising cotton but what I claim is :-
1. The treatment of raw silk, whether alone or in half silk fabric, with a
mixture of caustic alkali and glucose or glycerine all substantially as described.
2. The treatment of raw silk with a mixture of caustic alkali and glucose or
glycerine so as to loosen the bast or gumi and then removing it by a short
treatment with hot soap solution.
3. The removal of the silk gum, or bast, from silk contained in half-silk goods
substantially as herein described in the example.
Dated this 24th day of November 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.