Improvements in the Manufacture of Pyroxyline Solutions and Compounds for Photographic or other Films or Coatings and for Solid or Massive Artioles.
Year: 1892

page_text: Date of Application, 5th Apr., 1892
Complete Specification Left. 5th Jan., 1893-Accepted, 11th Feb., 1893
[Communicated from abroad by FREDERICK CRANE, of Bloomfield, New Jersey,
United States of America.]
Improvements in the Manufacture of Pyroxyline Solutions and
Compounds for Photographic or other Films or Coatings and for
Solid or Massive Artioles.
I, JOSEPH SINCLAIR FAIRFAX, of 433 Strand, in the County of London,
Patent Agent and Consulting Engineer, do hereby declare the nature of this
invention to be as follows:-
This invention, as communicated to me by my foreign correspondent relates to
improvements in the manufacture of pyroxyline solutions and compounds for
photographic or other films or coatings for various useful purposes.
The pyroxyline or nitro cellulose used in the manufacture of these compounds is
of the kind or grade known as soluble pyroxyline and is obtained by subjecting
vegetable fibre to the action of nitric acid, or of nitric and sulphuric acids, in a
manner well known.
"The solutions and compounds referred to are of a plastic or semi-plastic nature
at the time of manufacture, and are used for films or supports for photographic
negatives, or coatings spread upon stiff or flexible materials, or for solid or
massive articles.
The invention consists in the employment of certain known fluids which have
been 'discovered 'to possess the property of dissolving pyroxyline at ordinary
temperatures, and which also impart to the pyroxyline solution or compound made
by their aid, certain peculiar and desirable properties.
For many purposes for which pyroxyline compounds are, used it has been found
especially desirable to use a solvent for the pyroxyline which would volatilize with
considerable rapidity and at the same time would not absorb water or moisture, from
the atmosphere to any appreciable extent. So far as is known, no one solvent' for
pyroxyline combined both these properties of quick drying and non-affinity for
water, and it has been customary to use a compound solvent therefor. By this is
meant a solvent consisting of several distinct substances artificially united for the
purpose of producing the kind of solvent required, and this compound solvent
would consist in part at least-of liquids having an affinity for water; as, for
example, methyl-alcohol and acetone. The compound solvent would also partly
consist of non-hygroscopic liquids, (not having an affinity for water), such as amyl
acetate and benzine, the two classes of solvents being mingled in such proportions
as would be necessary-in each case-to produce a solvent sufficiently non-
'hygroscopic for the use for which the pyroxyline compound was required.
Now it has been discovered; and communicated to me by my foreign correspondent,
that the substance commonly known to the trade as acetone oil-when purified as
hereinafter mentioned is not only a powerful solvent of pyroxyline but dries with
\considerable rapidity that it is practically non-hygroscopic and can be used
either alone or in combination with some miscible and cheaper liquid, (such as
"benzine), as a solvent for pyroxyline in all pyroxyline compounds where heretofore
it' has been necessary to use compound solvents.
:
"This acetone oil is composed mainly of what are known as volatile ketones,
boiling below 150° C. These ketones may be obtained by the destructive distillation
of metallic acetates. While a chemically pure and dry acetate should yield a pure
acetone with simultaneous formation of the corresponding carbonates, the crude or
commercial acetate will yield, a distillate containing in addition to acetone and water
these, higher. ketones, along with certain acetates, and other decomposition products.

page_text: •
The acetone and water having been eliminated by the usual processes of
fractionation and absorption with dehydrating agents there remains au oil, which
my foreign correspondent informs me has valuable properties.
For some uses, however, it is not necessary to remove the acetone, for it is a
solvent of pyroxyline, and where a non-hygroscopic liquid is not required, it is not
injurious to the compound, even if present in considerable proportions; while if a
practically non-hygroscopic solvent is desired, a small proportion of acetone is
rendered inoxious by the presence of these non-hygroscopic higher boiling ketones.
When the acetone oil has been purified as above stated by removing the excess
of acetone and water, the volatile ketones remaining are but slightly absorbent of
water that is, are practically non-hygroscopic-and are miscible in large propor-
tions with petroleum and mineral napthas, and many of the other liquids useful in
pyroxyline solutions or compounds.
It is to be understood that I do not confine myself to any particular source for,
or process of, obtaining this mixture. For example, the acetates of calcium,
barium, strontium, lead, and probably others when destructively distilled, all
decompose with the formation of ketones as an invariable feature; and therefore,
I desire to avail myself of any of the acetates as a source of the said ketone oil
mixture. In applying the invention, I may employ these volatile ketones alone, or
with other miscible harmonious liquids in compounds of pyroxyline. Nor do I
intend to confine myself strictly to the boiling point mentioned, but merely give
the boiling point of 140° C. as one at which the most valuable of these products
will have come over in fractionation.
Having thus outlined the invention I will now proceed to specify some of the
mixtures as illustrative of the same, and indicate some of the uses to which
the said invention may be put.
For heavy solutions for the production of films which may be used as supports
for photographic negatives, and for other purposes requiring a solid and substantial
film, the following formulas will be found useful.
50 gallons volatile ketones or acetone oil
50 gallons wood alcohol
200 pounds soluble pyroxyline
Or
20 gallons of either petroleum naptha or benzole
20 to 50 gallons of volatile ketones or acetone oil
30 to 60 gallons of wood alcohol or acetone
200 pounds of pyroxyline.
I desire to state that generally, acetone may be substituted for wood alcohol, in
these formulas; and that where it is not essential that the solution should be non-
hygroscopic it may be used in considerably larger proportions than I have mentioned,
and methyl acetate and other harmonious miscible solvents may be added to these
formulas if desired. Either of the above formulas will give a clear, tough and
smooth film, and the heavy solution (or "dope," as it is termed) can be spread upon
a table, rollers, or upon a backing, in any known manner employed in producing
films or forming coatings.
It is to be understood that I do not confine myself to the formulas above given,
which may be varied in numerous ways to meet the requirements of the many
different uses to which these solutions or compounds are applied. For instance,
when the solid or massive form of pyroxyline compound is required for the produc-
tion of rolled, stamped, or moulded articles, the proportion of pyroxyline compound
will be largely increased, so that the formula might be 2 to 3 parts by weight of
the above specified menstrua to 2 parts by weight of pyroxyline, and colouring and
other matter can be added to the composition in a manner well known.
Dated this 5th day of April 1892.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Pyroxyline Solutions and
Compounds for Photographic or other Films or Coatings and for
Solid or Massive Articles.
I, JOSEPH SINCLAIR FAIRFAX, of 433 Strand, in the County of London,
Patent Agent and Consulting Engineer, 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, as communicated to me by my foreign correspondent, relates to
improvements in the manufacture of pyroxyline solutions and compounds for
photographic or other films or coatings, and for various other useful purposes; and
it constitutes improvements upon my application No. 6542 of even date herewith.
The pyroxyline (or nitro cellulose used in the manufacture of these compounds)
is of the kind or grade known as soluble pyroxyline and is obtained by subjecting
vegetable fibre to the action of nitric acid, or of nitric and sulphuric acids, in a
manner well known.
The solutions and compounds referred to are of a plastic or semi-plastic nature
at the time of manufacture, and are used for films or supports for photographic
negatives, or coatings spread upon stiff or flexible materials, or for solid or massive
articles.
The invention consists in the employment of certain known fluids which have
been discovered to possess the property of dissolving pyroxyline at ordinary
temperatures, and which also impart to the pyroxyline solution or compound made
by their aid, certain peculiar and desirable properties.
For many purposes, for which pyroxyline compounds are used, it has been found
especially desirable to use a solvent for the pyroxyline which would volatilize with
considerable rapidity, and at the same time would not absorb water or moisture
from the atmosphere to any appreciable extent. So far as is known, no one solvent
for pyroxyline combined both these properties of quick drying, and non-affinity
for water; and it has been customary to use a compound solvent therefor. By
this is meant a solvent consisting of several distinct substances artificially united
for the purpose of producing the kind of solvent required; and this compound
solvent would consist-in part at least of liquids having an affinity for water; as,
for example, methyl-alcohol and acetone. The compound solvent would also partly
consist of non-hygroscopic liquids, (not having an affinity for water), such as amyl
acetate and benzine, the two classes of solvents being mingled in such proportions
as would be necessary-in each case-to produce a solvent sufficiently non-hygro-
scopic for the use for which the pyroxyline compound was required.
Now it has been discovered, and communicated to me by my foreign corre-
spondent, that the substance commonly known to the trade as acetone oil-when
purified as hereinafter mentioned-is not only a powerful solvent of pyroxyline but
dries with considerable rapidity; that it is practically non-hygroscopic; and can
be used either alone or in combination with some miscible and cheaper liquid,
(such as benzine), as a solvent for pyroxyline in all pyroxyline compounds where
heretofore it has been necessary to use compound solvents.
This acetone oil is composed mainly of what are known as volatile ketones,
boiling below 140° C. These ketones may be obtained by the destructive distilla-
tion of metallic acetates. While a chemically pure and dry acetate should yield a
pure acetone with simultaneous formation of the corresponding carbonates, the
crude or commercial acetate will yield a distillate containing in addition to acetone
and water these higher ketones along with certain acetates and other decomposition
products.
The acetone and water having been eliminated by the usual processes of
fractionation and absorption with dehydrating agents there remains an oil, which
my foreign correspondent informs me has valuable properties.

page_text: For some uses, however, it is not necessary to remove the acetone, for it is a
solvent of pyroxyline, and where a non-hygroscopic liquid is not required, it is not
injurious to the compound, even if present.in considerable proportions; while if a
practically non-hygroscopic solvent is desired, a small proportion of acetone is
rendered inoxious by the presence of these non-hygroscopic higher boiling
ketones.
Where the acetone oil has been purified as above stated by removing the excess
of acetone and water, the volatile ketones remaining are but slightly absorbent of
water that is, are practically non-hygroscopic-and are miscible in large propor-
tions with petroleum and mineral napthas, and many of the other liquids useful in
pyroxyline solutions or compounds.
It is to be understood that I do not confine myself to any particular source for,
or process of, obtaining this mixture. For example, the acetates of calcium,
barium, strontium, lead, and probably others when destructively distilled, all
decompose with the formation of ketones as an invariable feature; and therefore,
I desire to avail myself of any of the acetates as a source of the said ketone oil
mixture. In applying the invention, 1 may employ these volatile ketones alone,
or with other miscible harmonious liquids in compounds of pyroxyline. Nor do I
intend to confine myself strictly to the boiling point mentioned, but merely to give
the boiling point of 140° C. as one at which the most valuable of these products
will have come over in fractionation.
Having thus outlined the invention, I will now proceed to specify some of the
mixtures as illustrative of the same, and indicate some of the uses to which the said
invention may be put.
For heavy solutions for the production of films which may be used as supports
for photographic negatives, and for other purposes requiring a solid and substantial
film, the following formulas will be found useful.
50 gallons volatile ketones or acetone oil
50 gallons wood alcohol
200 pounds soluble pyroxyline.
Or
20 gallons of either petroleum naptha or benzole
20 to 50 gallons of volatile ketones or acetone oil
30 to 60 gallons of wood alcohol or acetone
200 pounds of pyroxyline.
I desire to state that generally, acetone may be substituted for wood alcohol, in
these formulas; and that where it is not essential that the solution should be non-
hygroscopic it may be used in considerably larger proportions than I have
mentioned, and methyl acetate and other harmonious miscible solvents may be
added to these formulas if desired. Either of the above formulas will give a clear,
tough and smooth film, and the heavy solution (or "dope" as it is termed) can be
spread upon a table, rollers, or upon a backing, in any known manner employed'in
producing films or forming coatings.
It is to be understood that I do not confine myself to the formulas above given,
which may be varied in numerous ways to meet the requirements of the many different
uses to which these solutions or compounds are applied. For instance, when the
solid or massive form of pyroxyline compound is required for the production or
rolled, stamped or moulded articles, the proportion of pyroxyline compound will
be largely increased, so that the formula might be 2 to 3 parts by weight of the
above specified menstrua to 2 parts by weight of pyroxyline, and colouring and
other matter can be added to the composition in a manner well known.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim.is:
1. A film or substance solidified from a solution of pyroxyline with acetone oil,
substantially as and for the purpose hereinbefore described,

page_text: 2. A film or substance solidified from a solution of pyroxyline with purified
acetone oil or higher ketones, substantially as and for the purpose hereinbefore
described.
3. A film or substance solidified from a solution of pyroxyline, substantially in
the manner and in the proportions described and specified in the foregoing
formulæ.
4. A film or substance solidified from a solution of pyroxyline with acetone oil,
or of higher ketones and miscible harmonious substances, substantially as and for
the purpose hereinbefore described.
Dated this 5th day of January 1893.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.