Improvements in Treating Nitro-cellulose for the purpose of Coating or Impregnating Textile and other Fabrics.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c. Act, 1883), as required by
the decision of the Comptroller General of the 12th day of July 1898.
Date of Application, 14th Dec., 1896
Complete Specification Left, 14th Sept., 1897-Accepted, 30th Oct., 1897
Improvements in Treating Nitro-cellulose for the purpose of Coating
or Impregnating Textile and other Fabrics.
We, DANIEL MANSON SUTHERLAND, of Westholme, Sunbury on Thames, Manu-
facturer, and WILLIAM MCLAREN, of 70, Canfield Gardens, West Hampstead,
London, N.W., Manufacturer, do hereby declare the nature of this invention
to be as follows:-
Our invention relates partly to solutions of nitro-cellulose and analogous sub-
stances such as Parksine, Ivorine, xylonite and celluloid; and partly to the modes
of applying such substances to the purpose of coating or impregnating textile or
other fabrics or materials.
Such solutions have been used for many years, but their extensive adoption has
been retarded by the great expense involved in preparing the solvents used to
dissolve the nitro-cellulose or gun-cotton, and one object of our invention is to
produce an effective and economical solvent for such bodies, while another object
is to apply the solution when produced to the bodies to be impregnated or coated
in an improved manner.
Part of our invention also relates to the recovery of the solvents when evaporated
during the drying process in such a way as to further reduce the cost of solvent
used to a minimum.
Part of our invention consists in a new solvent which contains methyl alcohol.
methyl acetate, acetone, di-methyl acetate, allyl alcohol, and other empyreumatic
substances. We find that a mixture of these substances is obtained cheaply and
forms a rapid, powerful and perfect solvent of nitrated cellulose, pyroxyline, gun-
cotton, and also of Parksine, Ivorine, xylonite, celluloid and similar compositions
having nitro-cellulose as a basis.
Our new solvent also freely dissolves many oils, gums, pigments and dyes which
are required to be incorporated with the nitro-cellulose body for various purposes.
In one mode of producing our solvent we first prepare pyroligneous spirit by
distilling off the spirit from pyroligneous acid which is obtained by the destructive
distillation of wood, preferably hard wood. We re-distill the spirit three times
in succession. The last two distillations we preferably make in copper stills heated
by a steam coil, taking care that the temperature at which our solvent is distilled
does not exceed about 180° F.
For the last distillation we put in the still a small quantity of carbonate of soda
or carbonated soda ash. We find that from 1 to 1 per cent. by weight acts well.
This substance neutralises any free acid that may remain, and so the distillate
contains no free acid, but merely acid in combination with the different ethers.
The acid is mainly acetic acid, and it exists in the distillate in the form of methyl

page_text: acetate and di-methyl acetate. It is obvious that the quantity of carbonate of
soda required will vary according to the amount of free acid to be neutralised.
This we easily determine by exposing Litmus paper to the spirit as it leaves the
still, but other well known tests for acidity may also be adopted.
The spirit may be distilled oftener than three times, but we find that no practical
good results from excess of distillation. Various forms of distilling apparatus
may also be used, provided the apparatus be designed to allow a sufficiently
equable and controllable supply of heat. The mixture used by us is of a strength
of about 42° overproof, at a temperature of 50° F. It is free from acidity, and
is rich in methyl alcohol and methyl acetate.
In preparing a suitable solution according to one method we first place the
nitro-cellulose or other body having nitro-cellulose as a basis into a suitable
metallic or earthenware vessel, which vessel we fit with agitator arms or other
means of stirring, and we also provide convenient covers to make the vessel air-
tight when required. We then run in or pump in the required proportion of our
solvent, sometimes about five parts spirit to one part nitro-celluse or its equivalent,
The solid matter speedily becomes a pasty mass, and the arms are set in motion
to thoroughly mix. The stirring also hastens the disintegration of the nitro-
cellulose and increases the rapidity of solution. No heat need be employed.
We may now add castor oil or other suitable oil, and also suitable gums to give
elasticity, and further pigments or dyes to give colour, but we prefer to do this
at a later stage.
We then run the dissolved nitro-cellulose or celluloid into a long storage tank
which we make air-tight or nearly air-tight. This tank also we fit with agitator
arms. While the storage tank is being filled the displaced air is caused to escape
back to the vessel in which the solution has been formed.
Beneath the storage tank we place a series of vertical or horizontal mixing
tanks preferably portable, and each fitted with a stirring arrangement. These
mixing tanks are fed with the necessary quantity of dissolved nitro-cellulose or
other similar compound preferably by separate pipes and cocks.
Our object for having a series of mixing tanks is to have one for each colour
or series of colours which we desire to use.
After charging our mixing tanks with the proper proportion of dissolved nitro-
cellulose or nitro-cellulose compound, we prefer to add castor oil or other suitable
oil, and such gums as are necessary to give elasticity and cohesion, and we also
add pigments or dyes to give colour, all varying in quantity according to the
purpose for which the solution of nitro-cellulose is required. After addition of
these substances we thoroughly mix by the stirrers or other mixing device.
In cases where a very stiff composition is required we reduce the quantity of
the solvent and mix finally by passing through a pair of rollers having differential
speeds.
Our solution may be used for coating textile fabrics or for coating paper, plain
or printed, felt, leather-cloth, oil-cloth, linoleum, and all other materials in web
form having a fairly even surface, by using the well known spreading machine
as used for leather-cloth, containing as one of its essentials a knife or doctor blade
for spreading, and having a travelling band of rubber, leather or felt underneath.
The knife spreads the composition evenly as the fabrics to be coated are carried
under it by the travelling band.
We sometimes combine two or more fabrics together with our solution by passing
the fabrics between rollers and feeding the solutions into the nip of the rollers.
In coating embossed papers and fabrics of all kinds for varying purposes we
sometimes coat the material by dipping or brushing, or by a combination of those
processes.
Part of our invention, however consists in coating such surfaces by spraying the
solutions by means of a jet of compressed air. The compressed air and com-
position are led by separate flexible or rigid pipes which are joined together, and
terminate in a suitable nozzle which brings the air into contact with the composi-

page_text: tions, and distributes the latter over the embossed surfaces to be coated in the
form of spray. The nozzle may be either fixed or movable. When fixed, however,
the embossed surface must be moved about to ensure an even coating. Some-
times we use a transverse nozzle with or without lateral movement, and we arrange
the embossed fauric to be coated to pass at a uniform rate either below or above
the nozzles. Sometimes we throw the jet horizontally or at an angle while the
embossed fabric is moved upwards or downwards.
Such coating by means of compressed air is best done by conducting the process
in a closed space communicating with a drying room, and glazed with glass so
as to allow inspection of the process, while preventing the vapour from reaching
the operator. The pressure of air used may vary from 5 to 25 lbs. per square inch
according to the form of nozzle and the consistence of the composition used, and
the air should be as dry as possible. When necessary we dry the air by means of
such substances as calcium chloride and quicklime.
All the foregoing processes are carried out in a cool or a very slightly heated
atmosphere, in order to avoid premature evaporation of our solvent.
Immediately after the fabric or material has been treated by our solution either
by coating or impregnating it is at once passed into a drying room suitably heated
to about from 70° to 100° F., in order to evaporate the solvent and prevent the
compositions from becoming chilled or discoloured.
The materials to be dried may be carried through the heated drying room by
an endless band passing over rollers or hot plates, or round a drying cylinder
as in the manufacture of paper, or they may be suspended in loops on travelling
racks, as in the drying of printed wall papers. Small articles are placed in trays
or on shelves, and put into the drying room by hand. After drying the paper or
other material having a fairly even surface, we stamp or emboss suitable designs
or grains by means of engraved or electrotyped plates and rollers, which plates
or rollers may be heated or not, according to the effect required; but we prefer
to use them heated, as they then glaze and soften the coated material, rendering
it very flexible and agreeable to touch.
By this device we have succeeded in obtaining beautiful smooth and glazed, yet
flexible surfaces by simply passing suitable textile fabrics, preferably cotton velvets.
after being coated and dried, between a pair of smooth and highly burnished and
heated rollers under pressure.
Another part of our invention consists in recovering our evaporated solvent for
further use.
For this purpose we exhaust the air and vapour from the drying
room and from the chambers, in which the various operations are performed by
means of an air pump or other suitable device, and we force the said air and
vapour through one or more vessels such as Wolf's bottles communicating with
each other, and partly filled with castor oil. This oil has a great affinity for
and absorbs the vapour of our solvent, and the purified air is finally discharged
into the atmosphere.
The castor oil is renewed as required, and on becoming sufficiently saturated
with the spirit, withdrawn and used in compositions without distillation, or our
solvent may be recovered by distilling off from the castor oil.
A thickish solution may be prepared in the following proportions Our new
solvent 80 lbs. by weight, and nitro-cellulose or celluloid 15 lbs. by weight. The
composition may be made of this 'solution composed as follows:-Dissolved nitro-
cellulose 95 parts, castor oil 10 parts, pigments 5 parts, and methylated spirits
5 parts.
It is to be distinctly understood that our invention may be carried into effect
by various modifications which are hereinbefore indicated, although not fully
described,

page_text: Improvements in Treating Nitro-cellulose for the purpose of Coating
or Impregnating Textile and other Fabrics.
We, DANIEL MANSON SUTHERLAND, of Westholme, Sunbury on Thames, Manu-
facturer, and WILLIAM MCLAREN, of 70, Canfield Gardens, West Hampstead,
London, N.W., 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:-
Our invention relates to solutions of nitro-cellulose and analogous substances,
such as Parksine, Ivorine, xylonite, and celluloid; and to the application of such
substances for coating or impregnating textile or other fabrics or materials.
In one mode of producing our solvent we first prepare pyroligneous spirit by
distilling off the spirit from pyroligneous acid which is obtained by the destructive
distillation of wood, preferably hard wood. We re-distil the spirit three times
in succession. The last two distillations we preferably make in copper stills, heated
by a steam coil, taking care that the temperature at which our solvent is distilled
does not exceed about 180° F. We do not, however, confine ourselves to distilla-
tion at this temperature.
For the last distillation we put in the still a small quantity of carbonate of soda
or carbonated soda ash. We find that from 1 to 1 per cent. by weight acts well.
This substance neutralises any free acid that may remain, and so the distillate
contains no free acid, but merely acid in combination with the different ethers.
The acid is mainly acetic acid; and it exists in the distillate in the form of methyl
acetate and di-methyl acetate. It is obvious that the quantity of carbonate of
soda required will vary according to the amount of-free acid to be neutralised.
This we easily determine by exposing Litmus paper to the spirit as it leaves the
still, but other well-known tests for acidity may also be adopted..
The spirit may be distilled oftener than three times, but we find that no practical
good results from excess of distillation. Various forms of distilling apparatus
may also be used, provided the apparatus be designed to allow a thoroughly
equable and controllable supply of heat. The mixture used by us is of a strength
of about 42° over proof, at a temperature of 50° F. It is free from acidity, and
is rich in methyl alcohol and methyl acetate, though its composition varies con-
siderably. The following is the percentage composition of a sample:-
Methyl Alcohol
Acetone
Allyle Alcohol
Furfurol
Water and impurities
78-3
Methyl Acetate
4.4
1-5
Ethyl Alcohol
3:3
3.6
Di-methyl Acetate-
2.4
2.2
Pyroxanthine
1.8
2.5
In preparing a suitable solution according to one method we first place the
nitro-cellulose or other body having nitro-cellulose as a basis into a suitable
metallic or carthenware vessel, which vessel we fit with agitator arms or other
means of stirring, and we also provide convenient covers to make the vessel air-
tight when required. We then run in or pump in the required proportion of our
solvent, sometimes about five parts spirit to one part nitro-cellulose or its equivalent.
The solid matter speedily becomes a pasty mass and the arms are set in motion
to thoroughly mix. The stirring also hastens the disintegration of the nitro-
cellulose, and increases the rapidity of solution. No heat need be employed.
We may now add castor oil or other suitable oil, and also suitable gums to give
elasticity, and further pigments or dyes to give colour, but we prefer to do this
at a later stage.
i
4

page_text: Immediately after the fabric or material has been treated by our solution either
by coating or impregnating, it is at once passed into a drying room suitably heated
to about from 70° to 1000 F., in order to evaporate the solvent and prevent the
compositions from becoming chilled or discoloured.
The materials to be dried may be carried through the heated drying room by
an endless band passing over rollers or hot plates,, or round a drying cylinder
as in the manufacture of paper, or they may be suspended in loops on travelling
racks, as in the drying of printed wall papers. Small articles are placed in trays
or on shelves, and put into the drying room by hand.
Our invention consists in recovering our evaporated solvent for further use. For
this purpose we exhaust the air and vapour from the drying room and from the
chambers in which the various operations are performed by means of an air pump
or other suitable device, and we force the said air and vapour through one or more
vessels such as Wolf's bottles, communicating with each other, and partly filled
with castor oil. This oil has a great affinity for and absorbs the vapour of our
solvent, and the purified air is finally discharged into the atmosphere.
The castor oil is renewed as required, and on becoming sufficiently saturated
with. the spirit, withdrawn and used in compositions without distillation, or our
solvent may be recovered by distilling off from the castor oil.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
Means for the recovery of the solvent after use in the solution and application
of nitro-cellulose or nitro-cellulose compounds or other similar substances by
evaporating and passing the vapour through castor oil in which the vapour is
absorbed substantially as and for the purposes herein before described.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents for the Applicants.