~The Industrial Uses of Cellulose.~
C. F. CROSS (Cantor Lectures, Soc. of Arts, 1897).
(p. 273) A series of three lectures, in which the more important
industries in cellulose and its derivatives are dealt with on their
scientific foundations, and by means of a selection of typical problems.
In reference to textiles, the small number of vegetable fibres actually
available, out of the endless variety afforded by the plant world, is
referred to the number of conditions required to be fulfilled by the
individual fibre, thus: yield per cent. of harvested weight or per unit
of field area, ease of extraction, the absolute dimensions of the
spinning unit, and the proportion of variation from the mean dimensions;
the relative facility with which the unit fibre can be isolated
preparatory to the final twisting operation; the chemical constants of
the fibre substance, especially the percentage of cellulose and degree
of resistance to hydrolysis. It is suggested that any important addition
to the very limited number fulfilling the conditions, or any great
improvement in these, can only result from very elaborate artificial
selection and cultural developments on this basis.
The paper making fibres are shown to fall into a scheme of
classification based on chemical constitution, and consisting of the
four groups: (a) Cotton [flax, hemp, rhea], (b) wood celluloses,
(c) esparto, straw, and (d) lignocelluloses. Papers being exposed to
the natural disintegrating agencies, more especially oxygen, water (and
hydrolysing agents generally), and micro-organisms, the relative
resistance of the above groups of raw materials is discussed as an
important condition of value. The indirect influence of the ordinary
sizing and 'filling' materials is discussed. The paper-making quality of
the fibrous raw materials is also discussed, not merely from the point
of view of the form and dimensions of the ultimate fibres, but their
capacity for 'colloidal hydration.' This is complementary to the action
of rosin, i.e. resin acids, in the engine-sizing of papers; and the
proof of the potency of this factor is seen in the superior effects
obtained in sizing jointly with solutions of cellulose and, more
particularly, viscose and rosin. Wurster's much-cited monograph of the
subject of rosin-sizing ['Le Collage des Papiers,' Bull. Mulhouse, 1878]
neglects to take into consideration the contribution of the cellulose
hydrates to the total and complex sizing effect, and hence gives a
partial view only of the function of the resin acids.
In further illustration of fundamental principles various developments
in the textile industries are discussed, e.g. the bleaching of jute,
cotton, and flax, and special developments in the spinning of rhea and
flax.
The concluding lecture deals with later progress in the industrial
applications of cellulose derivatives, chiefly the sulphocarbonate
(viscose); the nitrates, in their applications to explosives, on the one
hand, and the spinning of artificial fibres (lustra-cellulose), on the
other; and the cellulose acetates.
~La Viscose et le Viscoide.~
C. H. BARDY (Bull. Soc. d'Enc. Ind. Nationale, 1900, March).
This is a report presented to the Committee of Economic Arts of the
above Society, dealing with the industrial progress in products obtained
by means of the sulphocarbonate of cellulose (viscose).
The following developments are noted:
_Engine-sized Papers._--The viscose, by coating the fibres with
regenerated cellulose hydrate, adds very much to the tensile strength of
papers. Increase of 40-60 p.ct. is attainable by addition of cellulose
in this form from 1-4 p.ct. on the weight of the paper.
_Viscoid._--Solid aggregates are formed by incorporating viscose with
mineral matters, hydrocarbons, &c. Products are cast or moulded into
convenient forms, and, after purification and sufficient ageing, are
available for various structural uses.
_Paint._--The viscose is used as a vehicle for pigments, the mixture
being used either as a paint or for coating papers with fine surfaces,
such as required in the reproduction of photo-blocks. In these
applications the extraordinary viscosity of the product conditions the
economic use of the cellulose in competition with oils, on the one hand,
and organic colloids, such as gelatine, casein, &c., on the other.
By suitable alteration of the formula for making the paint a product is
obtained which has an extraordinary power of removing paint from old
painted surfaces. The product has been officially adopted by the French
Admiralty, and receives extensive application in removing the paint from
ships.
_Films._--Films are produced from the viscose itself in various ways.
Plane or flat by solidifying the viscose on glass surfaces, removing the
by-products and rolling the films. The film is also produced by
applying the viscose on textile fabrics, drying down, and fixing on a
stenter machine, then washing away the alkaline by-products from the
fixed film. A large number of industrial effects are obtained by
suitably varying the mixtures applied.
_Cellulose-indiarubber._--The viscose, in its concentrated form, can be
incorporated with rubber-hydrocarbon mixtures, and these mixtures can be
used both as water-proofing films, as applied to textiles, or can be
solidified into the class of goods known as 'mechanicals.' The cellulose
not only cheapens the mixture, but produces new technical effects.
_Spinning._--The viscose is spun by special methods, patented by C. H.
Stearn. As produced in thread form, the diameters are approximately
those of natural silk. In commercial form it is a multiple thread (of 15
or more units) at from 50-200 deniers on the silk counts. It is a thread
of high lustre, and more nearly approaches the normal cellulose in
chemical properties than any of the other artificial silks. It can also
be spun in threads of very much larger diameter, which can be used as a
substitute for horsehair, for carbonising for incandescent electric
lamps, &c.
_Cellulose Esters._--These are conveniently made from cellulose,
regenerated from the solution as sulphocarbonate. The tetracetate is
made from this product on the industrial scale. Nitrates are
conveniently made by treatment with the ordinary mixed acids. For fuller
details the original report may be consulted.
VISKOS.
R. W. STREHLENERT (Svensk Kemisk Tidskrift, Stockholm, 1900, p. 185).
A report on the industrial development of viscose, covering essentially
the same ground as the above.
~Ueber die Viscose.~
B. M. MARGOSCHES (Reprint from Zeitschrift fuer die gesammte
Textil-Industrie, 1900-01, Nos. 14-20).[11]
~Report of Committee on the Deterioration of Paper.~
(Soc. of Arts, 1898.)
(p. 304) The Report of a Representative Committee appointed by the
Society of Arts to inquire into the question of qualities of book papers
in relation to their several applications, and more especially for
documents of permanent value.
The report first discusses the two directions of depreciation of papers
in use: (1) Actual disintegration shown by loss of resistance to
fracture by simple strain, and by loss of elasticity--i.e. increase of
brittleness; (2) discolouration. These are independent effects, but
often concurrent. They are the result of chemical changes of the
cellulose basis of the paper, brought about by acids or oxidants used in
the process of manufacture, and not completely removed from the pulp, or
by acid products of bleaching--e.g. oxycelluloses or chlorinated
derivatives; again, by the changes of starch used as a 'sizing' agent,
or by oxidations induced by rosin constituents when the rosin is used in
excess. Discolouration is an attendant phenomenon of these changes, but
is more frequently due to the presence of the lower-grade celluloses
(esparto and straw) and the lignocelluloses (mechanical wood-pulp).
The physical and chemical qualities of papers depending primarily upon
their fibrous or pulp basis, and in a secondary degree upon the kind and
proportion of the constituents added for the purpose of filling and
'sizing,' the report concludes with the following recommendations,
positive and negative, under these heads:
The Committee find that the practical evidence as to permanence fully
confirms the classification given in the Cantor Lectures on 'Cellulose,'
1897 [J. Soc. Arts, xlv. 690-696], and which ranges the paper-making
fibres in four classes:
(A) Cotton, flax, and hemp (rhea).
(B) Wood celluloses, (a) sulphite process and (b) soda and
'sulphate' process.
(C) Esparto and straw celluloses.
(D) Mechanical wood-pulp.
In regard, therefore, to papers for books and documents of permanent
value, the selection must be taken in this order, and always with due
regard to the fulfilment of the conditions of normal treatment above
dealt with as common to all papers.
The Committee have been desirous of bringing their investigations to a
practical conclusion in specific terms--viz. by the suggestion of
standards of quality. It is evident that in the majority of cases there
is little fault to find with the practical adjustments which rule the
trade. They are, therefore, satisfied to limit their specific findings
to the following--viz. (1) normal standard of quality for book-papers
required for publications of permanent value. For such papers they
specify as follows:
Fibres: Not less than 70 p.ct of fibres of class A; class D excluded.
Sizing: Not more than 2 p.ct. rosin, and finished with the normal
acidity of pure alum; starch excluded.
Loading: Not more than 10 p.ct. total mineral matter (ash).
(2) With regard to written documents, it must be evident that the proper
materials are those of class A, and that the paper should be pure and
sized with gelatin, and not with rosin. All imitations of high-class
writing-papers which are, in fact, merely disguised printing-papers,
should be carefully avoided.
_Appendix._--To the Report is added 'Abstracts of Papers' in
'Mittheilungen aus den Koniglichen Technischen Versuchsanstalten,
Berlin,' for the years 1885-1896 inclusive--which is, in fact, a summary
of the investigations of the Institution in connection with paper and
paper-standards.
* * * * *
(p. 273) ~Special Industrial Developments.~--From the point of view of the
chemist there has been a very large development of the cellulose
industries during the last five years. This is not so much marked by the
gradual and progressive growth of the well-established industries, as by
the success of the newer ones, with the attendant forecast of enormous
developments of the industries in artificial products, the manufacture
of which rests upon a purely chemical basis. We can, of course, only
treat them from this limited standpoint, and so far as they involve and
elucidate chemical principles.
~I. Chemical Treatments of Raw Materials.~
(a) ~Flax-spinning.~--The treatment of the roving on the spinning-frame
by the addition of reagents to the macerating liquid--otherwise and
usually hot water--continues to be justified by results. The technical
basis of the process and the reactions determined in the spinning-trough
by the alkaline salts used--chiefly sulphite and phosphate of soda--is
set forth in the original work, p. 280. Since that time a sufficient
period has elapsed to judge the effects, both technical and industrial,
by the results of a commercial undertaking based on the exclusive use of
the process. Such a concern is the Irish Flax Spinning Company of
Belfast. At this mill the experience is uniform and fully established
that by means of the process the drawing, i.e. spinning, quality of
inferior flaxes is very considerably appreciated, enabling the spinner
to use such flaxes for yarns of fineness which are unattainable by the
ordinary method of spinning through hot water. Notwithstanding the
success of this undertaking the development of the method is still
inconsiderable. It is none the less a further and forcible demonstration
of the existence of margins of increased technical effect which it is
the work of the scientific technologist to exploit.
(b) ~Wood-pulp and Methods of Manufacture.~--There is a steady growth in
the consumption of wood-pulps (cellulose) relatively to other materials.
In regard to the paper-trade of the world, this continues to be one of
the most prominent characteristics of its evolution. In the United
Kingdom the conditions of its competition are of a more special kind by
reason of the firm foothold of esparto, which is a most important staple
in the manufacture of fine printings. Whereas the consumption of esparto
remains nearly stationary at about 200,000 tons per annum, the
importation of wood-pulps has shown the extraordinary rate of increase
of doubling itself every five years. But in the group 'wood-pulps' the
trade returns have until recently included the 'mechanical' or ground
wood-pulps. From 1898 we have separate returns for the chemical or
cellulose pulps, and in 1899 the tonnage reached nearly to that of
esparto, with a total money value about 80 p.ct. greater. When it is
remembered that this is one of the newer chemical industries in
cellulose products, and that these large commercial results have been
accomplished during a period of twenty years, we are impressed with the
scope of the industrial outlook to the chemist, afforded by the arts of
which cellulose is the foundation.
It may be noted that there have been no important developments in the
purely chemical processes involved in the several systems of preparing
cellulose from wood. The acid methods (bisulphite processes) have
developed much more extensively than the alkaline, the latter including
the caustic soda and the mixed sulphide ('Dahl') process. The bisulphite
processes depended in the earlier stages upon the efficiency of
lead-lined digesters. But the problem of acid-resisting linings has been
much more perfectly solved in later years in the various types of cement
and other silicate linings now in use. The relative permanency of these
linings has had an important effect on the costs of production. Further
economies result from the use of digesters of enormous capacity, dealing
with as much as 100 tons of wood at one operation. As a combined result
of economic production and active competition, the selling prices of
'sulphite pulp' have moved steadily downwards in relation to other
half-stuffs and raw materials. As a necessary consequence the prices of
those which it has gradually displaced have depreciated, and a study of
the price and tonnage-equilibrium as between rags, esparto, and
wood-pulp over a series of years forms an interesting object-lesson in
the struggle for survival which is an especial mark of modern industry.
For these matters the reader is referred to the special literature of
the paper-making industry.[12]
It is not a little remarkable that the main by-product of these
bisulphite processes--the sulphonated derivatives of the lignone
constituents of the wood--is still for the most part an absolute waste,
notwithstanding the many investigations of technologists and attempts to
convert it to industrial use (see p. 149). Seeing that it represents a
percentage on the wood pulped equal to that of the cellulose obtained,
it is a waste of potentially valuable material which can only be termed
colossal. Moreover, as a waste to be discharged into water-courses, it
becomes a source of burden and expense to the manufacturer, and with the
increasing restrictions on the pollution of rivers it is in many
localities a difficulty to be reckoned with only by the cessation of the
industry. The problem in such cases becomes that of dealing with it
destructively, i.e. by evaporation and burning. In this treatment the
obviously high calorific value of the dissolved organic matter (lignone)
appears on the 'credit' side. But where calcium and magnesium
bisulphites are used, the residue from calcination is practically
without value. It appears, however, that by substituting soda as the
base the alkali is recoverable in such a form as to be directly
available for the alkaline-sulphide or 'Dahl' process. As a more
complicated alternative the soda admits of being recovered on the lines
of the old black-ash or Leblanc process, and the sulphur by the now
well-established 'Chance' process, for which, of course, an addition of
lime is necessary to the fully evaporated liquors previously to
calcining. The engineering features of the system, so far as regards
evaporating and calcining, are the same. For economic working there is
required (a) evaporation by multiple effect and (b) calcining on the
continuous rotary principle. For the latter a special modification has
been devised so that the draught of air is concurrent with the movement
of the charge in the furnace, securing a progressively increasing
temperature within the furnace. This interesting development of the
chemical engineering of wood-pulp systems has been elaborated by two
well-known technologists, Drewson and Dorenfeldt, and readers who wish
to inform themselves in detail of these developments are referred to the
various publications of these inventors.
Assuming the present necessity of a destructive treatment of the
by-products of the bisulphite processes, the scheme has many advantages.
The soda-bisulphite liquors are more economically prepared; the pulp
obtained is superior in paper-making quality to that resulting from the
lime or magnesia (bisulphite) processes: it is more economically
bleached.
Then, as pointed out, the soda may on the one plan be obtained in a form
in which it is immediately available as a powerful hydrolysing alkali in
the manufacture of a 'soda' pulp. These two systems become, therefore,
in a new sense complementary to one another. Lastly, it is obvious that
the employment of soda as the base opens out a new vista for developing
the electrolytic processes of decomposing common salt.
The authors have assisted in preparing plans for a comprehensive
industrial scheme combining all these more modern developments. In this
scheme it is only the combination which is novel, and as it involves no
new principles in the chemical treatments of the materials we are not
further concerned with it than to have briefly sketched its economic
basis. This may be summed up in result in the important question of cost
and selling price, and the estimate is well grounded that by means of
this scheme _bleached wood-pulp_ can be sold on the English market at
10l. a ton. It is important to note this figure and to compare it with
the prices of twenty years ago. The fall has been continuous,
notwithstanding the influence of the opposing factors of increasing
consumption, exhaustion of accessible supply of timber, and relative
appreciation of the essential costs of steam, chemicals, and labour. It
is important in forecasting the future, since the youngest and
apparently most promising of the 'artificial' cellulose industries
employs wood-cellulose by preference as its raw material (see p. 173).
As a last point it must be considered that as chemists we are bound to
anticipate the realisation of value in the soluble by-products of the
bisulphite processes. Outside the intrinsic interest attaching to the
solution of this problem, it carries with it the promise of a further
economy in the production of wood-cellulose.
~Bleaching of Vegetable Textiles.~--By far the largest of these industries
are those which are engaged in producing the 'pure white' on cotton and
flax goods. The process, considered chemically, is simply that of
isolating a pure cellulose, and we endeavoured to give due prominence to
this view in the original work. It is important to insist upon it for
the reason that this view gives the due proportion of chemical value to
the several contributory treatments--alkaline hydrolyses (caustic lime
and soda boils), hypochlorite oxidations, and incidental acid treatments
(souring). The first of these is by far the largest contributor of
'chemical work,' though the second, by being the agent for the actual
whitening effect or bleaching action proper, occupies a position of
often exaggerated importance.
In bleaching processes there has been no radical change of system on the
large scale since the introduction of the 'Mather' kier in 1885, and the
associated change from lime and ash boiling to the caustic soda
circulating boil with reduced volume of lye, which this mechanical
device rendered practicable. It is outside the scope of this work to
follow up this branch of technology in any detail, and we cannot discuss
the evolution of systems on variations of detail where no essential
principle is involved. But we have to notice a very recent development
which has only just begun its industrial career, and which does give
effect to a principle of treatment not previously applied. This is
tersely stated by its originator, William Mather,[13] in the
expression, 'it is more economical to make liquids pass through cloth
than to make cloth pass through liquids.' The starting point of this
development is the invention of a complete self-contained machine in
which a rolled batch of cloth can receive a succession of chemical
treatments, with accessory washings--the solutions, or wash waters,
being circulated through the cloth. The essential fact on which this
system is based is that a perfect liquid circulation can be maintained
from selvedge to selvedge through the folds of a tightly rolled batch of
cloth. Such circulation is therefore quite independent of the diameter
of the batch. If we consider a cloth under chemical treatment with
solutions, it is clear that the reactions and interchanges of soluble
matters within the cloth, within the twisted elements of the yarn, and
in the last grade of distribution within the actual ultimate fibres, are
subject to capillary transmission, and osmotic exchange. There is a
mixture of these molecular effects, with the circulation in mass,
sweeping both faces of the cloth. It is obvious that for the mass effect
a relatively very small volume of circulating liquid is necessary to
maintain uniform conditions of action. In the actual disposition of the
machine the rolled batch of cloth nearly fills the cylindrical space of
what we may call the reaction chamber, and the circulation of the liquid
is maintained by a circulating pump and a differential pressure in the
horizontal plane across and through the folds of the batch. This is in
the meantime kept in slow revolution. For a full description of these
mechanical details the reader is referred to the original patent
specifications [Engl. Pat. 23,400, 23,401; 1900, W. Mather]. If we again
consider the principles involved, they are very much as set forth in
our original work (pp. 288-291). Boiling processes in which a
relatively large volume of liquid is used are wasteful of steam, the
active agent is unnecessarily diluted or used in superfluous quantity,
and the soluble by-products, being continually removed as formed, cannot
so effectively contribute by secondary actions to the chemical work. The
new mechanical appliance enables us to further reduce the volume of
liquid required in the alkaline-hydrolytic treatment of vegetable
textiles, and where advantageous to bring the treatment down (or up) to
a process of steaming with the active agent dissolved in a minimum
proportion of water relative to the cloth. This concentration of effect
is of importance in flax cloth, and especially linen treatment, where
the peculiarly resistant cutocelluloses have to be attacked and a
considerable proportion of waxy by-products to be removed. These points
are the basis of the special process of Cross and Parkes [Engl. Pat.
25,076/ 99] for steaming flax (and cotton) goods with an emulsion
containing, in addition to the special hydrolysing agent--caustic
soda--mixtures of soap with 'mineral' or other oils, the presence of
which effectually aids the removal of the by-products in question.
A complete system on these lines is now working on the industrial scale
in the Belfast district. The results are not merely economical in
largely reducing the number of alkaline boiling treatments required on
the old plan of pan or 'pot' boiling, but are visible in the strength
and finish of the linens so treated.
For cotton bleaching the costs may be put down at a fraction of those of
the Irish linen bleach. The economical advantages of the new system are
obviously less in relation to the lesser total costs. But there are
other points which have come into more prominent influence. The
mechanical wear and tear on the cloth is considerable in the ordinary
process, more especially in the mangle-washes. As a result the
adjustment of warp and weft is more or less disturbed. These defects are
absent from a system which operates on the cloth in a fixed position.
But as we are mainly concerned with the purely chemical factors we
cannot pretend to deal with textile questions. We have to notice the
remaining element of chemical economy as it involves a fundamental
principle. The practice of washing residues or products of reaction free
from reagents and soluble by-products involves a well-known mathematical
law, under which the rate of purification is a function rather of the
_number_ of successive changes of washing liquid than of the volume of
the latter. The ordinary practice of textile washings entirely ignores
this principle, and the consumption of water in consequence may reach
many thousand times the economic minimum. With supplies of water often
in indefinite excess of requirements, even in this most wasteful method,
bleachers are in no need to consider the question of consumption. But
leaving aside particular and local considerations of advantage the fact
is that the new system gives control of the practice of washing,
enabling the operator to adapt an important element of the daily routine
to a fundamental principle which has been almost universally ignored.
In the oxidising processes which follow the alkaline treatments, the
hypochlorites are still the staple agents. Owing to the steady relative
fall in the selling prices of the permanganates these are coming into
more extensive use, but the consumption is still small, and they are
mainly used for certain special effects, chiefly in linen or more
generally flax cloth bleaching.
~Paper-pulp Spinning.~--Paper is a continuous web or fabric produced by
the interlocking of the structural fibrous units of the well-known short
length. In Japan and other countries paper is made to serve for all or
some of the purposes for which we employ string or twine, and to give
the necessary tensile strength the paper is twisted or rolled on itself.
Such twisting, however, adds nothing to the intrinsic tensile qualities
of the original paper.
A new technical effect is realised in this direction by the treatment of
paper-pulp in the process of its conversion into a continuous web: The
pulp is formed into continuous strips of convenient breadth (usually
from 2 to 8 mm.), these receive a 'rolling-up' treatment immediately
following the squeeze of the press rolls by which the superfluous water
is removed: they are then further but incompletely dried, and in this
condition are subjected to a final spinning or twisting treatment on
ring-spinning machinery of special construction.
Such a process was originally patented by C. Kellner in this country
(E.P. No. 20,225/1891), and is fully described in his specification.
Later improvements in detail were patented by G. Tuerk (E.P. 4621/1892).
A joint system is now being industrially developed in Germany by the
Altdamm-Stahlhammer Pulp and Paper Company under the technical direction
of Dr. Max Mueller, and there appears to be every prospect of the product
taking a position as a staple textile.
The process has only the incidental interest in connection with our main
subject, that it employs chiefly the 'chemical' pulps or celluloses as
raw materials. The industrial future of the application must, of course,
be largely determined by costs of production, as the directions of
application in the weaving industries will be limited by the necessarily
inferior grade of tensile strength belonging to these products and the
degree by which this is lowered on complete wetting. All these questions
have been duly weighed by those engaged in this interesting development,
and the conclusion of those qualified to judge is that the new industry
has vindicated for itself a permanent position.
~II. The Chemical Derivatives of Cellulose~, in their industrial aspects,
have come to occupy a profoundly important position in the world's
affairs. In the way of any essential alteration of the perspective from
that obtaining in 1895 we have nothing to chronicle. No new derivatives
of industrial importance have been added in that period; but certain new
methods incidental to the preparation of well-known compounds or for
converting them into more generally available forms have been
introduced, and these are contributing to the rapid expansion of the
'artificial' cellulose industries.
Of the cellulose esters the nitrates are still the only group in
industrial use. There uses for explosives have attained immense
proportions, and their applications for structural purposes are
continually on the increase. The manufacture of smokeless powders on the
one hand, and of celluloid and xylonite (both in the form of films and
solid aggregates) on the other, has taken no new departure. The industry
in 'artificial silks' or 'lustra-celluloses,' by the collodion processes
also, whilst presenting features of unusual interest attaching to rapid
expansion, has been barren of contribution of fundamental scientific or
technical importance. The tetracetate is now manufactured on the large
scale, but the product has yet to make its market.
The process of mercerising cotton yarns and cloth has been developed to
an industry of colossal dimensions, and the growth has been especially
rapid during the last five years. Significant of the technical progress
in these two industries, with their common aim of appreciating cellulose
in the scale of textiles by approximating its external properties in
those of silk, is the appearance of a monograph of the technology of
each, notices of which have been previously given (pp. 22-26).
There is little doubt, however, that the question of the future
industry in the various forms of cellulose, thread, film, structureless
powder or solid aggregate, obtainable by artificial means, mainly turns
upon cost of production. Irrespective of cost, there would, no doubt, be
a market for all these products, based upon such of their properties or
effects as are indispensable and not otherwise obtainable. As an
illustration, we may cite the extraordinary selling prices of 40-50 fr.
per kilo, for the 'artificial silks' (collodion process) which ruled
some three years ago; and we may note that for a special application of
viscose the dissolved cellulose is paid for at the rate of 10 per
lb. These facts are certainly worthy of mention, and should be borne in
mind as an index of some special features of modern manufacturing
industry. But with a material like cellulose rendered available in a new
shape the question which always arises more prominently than that of
limited uses at high prices is that of consumption on the extensive
scale which marks the older and well-known products. That question is
rapidly solving itself in this country as regards the 'artificial
silks.' There is at present a limited market at 9s.-10s. per lb., a
price which on the one side excludes extensive consumption, and on the
other practically bars manufacture in this country by any of the
collodion systems. It will appear from a very elementary calculation of
what we may call the theoretical costs that the above selling price
would not have a remunerative margin. The theoretical costs are made up
of
Raw materials[14] {Cotton. Nitrating acid. Ether-alcohol (solvent).
{Denitrating chemicals.
{(a) Nitrating and preparing collodion. Denitrating
{ and bleaching.
Labour {(b) Textile operations. Spinning. Winding and twisting.
{Rewinding.
Power {Making, filtering, and distributing collodion.
{Driving textile machinery.
Added to which are the costs of expert management and supervision and
general establishment expenses. It is evident that raw materials make up
a large fraction of the total cost; also that a very large item is the
waste work of converting the cellulose into nitrate, only to remove the
nitric groups so soon as the cellulose is obtained as thread.
It is clear that the aqueous solutions of cellulose have a double
advantage in this respect--not only do they readily yield an
approximately pure cellulose as a direct product of regeneration or
decomposition, but the first cost of the solution is very much less.
With these newer products, therefore, the spinning problem enters on a
new phase of struggle. It is certain that at selling prices at or about
5s. to 7s., very large markets will be open to the product or
products. The two processes which are or may be able to fulfil this
demand are those based (1) on cuprammonium solutions of cellulose, (2)
on the sulphocarbonate or viscose. As regards _first cost_ of the
solution the latter has a large advantage. One ton of wood pulp (at
12l.) can certainly be obtained in solution in a condition ready for
spinning at a total cost (materials) of less than 30l. The
cuprammonium process, so far as 'outside' information goes, requires for
production of the solution (1) cotton as raw material, (2) ammonia
(calc. as concentrated aqueous) equal to 1-1/2 times its weight, and
(3) metallic copper 25 p.ct. of its weight; and the costs are
approximately 100l. per ton. It is obvious that the materials are
recoverable from the precipitating-bath, but at a certain added cost. We
have no statements as to the proportion recoverable nor the costs
incurred, and we are therefore unable to measure the total net cost of
the regenerated cellulose by this process. It is certainly much less
than by the collodion processes. As to the textile quality of the
thread, the product has not yet been on a sufficiently wide selling
basis for that to have been determined. There are a great many factors
which enter here. Not merely the external characters of lustre,
softness, and translucency, but the all-important quality of uniformity
of thread. The collodion-spinning is a process still very defective in
this respect, and the defect is no doubt referable to the difficulty of
securing absolute physical invariability of the collodion. It is to be
regretted, in the interests of scientific development, that none of the
technologists who have published investigations of these processes have
entered into the discussion of the fundamental factors of the spinning
processes; we are, therefore, unable at this stage to discuss these
elements of a full comparison in greater detail. We cannot, for this
reason, say how far the cuprammonium process diverges in point of
control from the standard of the collodion processes. Of the 'viscose'
product we have a more intimate knowledge, and it certainly reaches a
higher general standard than the older and now well-known artificial
silks. The process is also sufficiently developed to enable the total
costs of production to be estimated at a figure less than one-half that
of the 'collodion' processes. This would assure to this system an
_entree_ in this country, and a basis of expansion limited only by the
ordinary laws of supply and demand.
This prospect is opened up precisely at the moment when, for various
reasons connected both with the difficulties of manufacture and the
narrowing of the margin of profit, the proprietors of the two systems of
collodion-spinning have decided to abandon all idea of manufacturing by
these systems in this country.[15] We leave the discussion of the
industrial problem at this point.
In regard to other developments based upon the exceptional character and
properties of the sulphocarbonate, their further discussion will
exemplify no general principles; and as regards technical detail they
have been dealt with in the papers previously noticed.
As a purely general question, if there is to be any industry in these
'artificial' forms of cellulose, commensurate with the magnitude that
usually belongs to the cellulose industries, it must come by way of a
plastic or soluble form prepared at low cost, and conserving the
essential molecular properties of the cellulose aggregate. These are the
particular features of the sulphocarbonate. The obvious difficulties in
the way of its industrial applications are those caused by the presence
of alkali and sulphur compounds. These are dealt with by appropriate
chemical means; but the fact that there is a special chemistry of the
product has rendered its industrial progress slow. The work of the last
five years in this, as in other applications of cellulose in its many
derived forms, has resulted in a considerable addition to the domain of
practical chemistry.
Further developments will make an increasing demand upon our grasp of
the fundamental constitutional problems, to which it is the main purpose
of the present volume to contribute.
FOOTNOTES:
[11] This is the most complete notice that has appeared and the
bibliography is exhaustive. The publication comes into our hands too
late to be noticed in detail.
[12] _Text-book on Paper-making_, Cross and Bevan (Spon, London: second
edition, 1900). _Chemistry of Paper-making_, Griffin and Little (New
York, 1894: Howard Lockwood & Co.). _Handbuch d. Papierfabrikation_, C.
Hofmann (Berlin). _Paper Trade Review_, London (weekly).
_Papier-Zeitung_, Berlin.
[13] William Mather, M.P., of the firm of Mather & Platt, Limited,
Manchester.
[14] The actual costs varying considerably in the various countries, we
cannot make any specific statement. But from estimates we have made, the
costs of obtaining cotton in filtered solution as collodion multiply its
value by 12-14, the denitrations adding further costs and raising this
multiple to 18-20. In the same estimates we arrived at the conclusion
that the item for raw materials made up 60 p.ct. of the total cost of
the yarn.
[15] The recent failure of a French company founded for the exploitation
of the cuprammonium process may be taken as showing that it presents
very considerable technical difficulties. It is a matter of common
knowledge that this company _estimated_ the costs of production to be
such as to enable the product to be sold at 12 fr. per kilo., whereas
the costs actually obtaining were a large multiple of this figure.
INDEX OF AUTHORS
Bardy, C. H., 157
Bokorny, T., 43
Bronnert, E., 54
Bumcke, G., and Wolffenstein, R., 67
Buntrock, 25
Cross, C. F., 139, 152, 155
Cross, C. F., and Bevan, E. J., 92
Cross, C. F., Bevan, E. J., and Briggs, J. F., 118
Cross, C. F., Bevan, E. J., and Heiberg, T., 114
Cross, C. F., Bevan, E. J., and Smith, C., 101, 103, 105, 114, 145
De Haas, R. W. T., and Tollens, B., 151
Faber, O. v., and Tollens, B., 71
Feilitzen, H. v., and Tollens, B., 154
Fenton, H. J. H., 8
Fenton, H. J. H., and Gostling, M., 86
Fraenkel, A., and Friedlaender, P., 26
Gardner, P., 22
Gilson, E., 112
Hancock, W. C., and Dahl, O. W., 135
Hoffmeister, W., 96, 100
Kleiber, A., 97
Kroeber, E., 121
Krueger, M., 119
Lange, H., 25
Lewes, V. H., 15
Luck, A., and Cross, C. F., 45
Margosches, B. M., 159
Morrell, R. S., and Crofts, J. M., 114
Mylius, F., 21
Nastukoff, H., 74
Omelianski, V., 76
Ruff, O., 117
Salkowski, E., 113
Schoene, A., and Tollens, B., 124
Seidel, H., 149
Sherman, H. C., 137
Simonsen, E., 146
Storer, F. H., 142
Strehlenert, R. W., 158
Suringar, H., and Tollens, B., 16, 124
Suevern, C., 63
Tollens, B., 148, 151
Tollens, B., and Glaubitz, H., 122
Vignon, L., 43, 70, 72, 94
Will, W., and Lenze, P., 41
Winterstein, E., 109, 144, 153
INDEX OF SUBJECTS
Acetone, action on cellulose nitrates of diluted, 46
Acid-cellulose, 68
Acids, volatile, from cellulose, 145
_AEschynomene aspera_, 135
Alcohol from cellulose and wood, 146
Alcoholic soda, mercerisation results with, 26
Alkali-cellulose, effects of long storage on, 31
Amyloid, vegetable, 153
Arabinose from gluconic acid, 117
'Ash' of plants, 13
_Bacterium xylinum_, 85
Barley plant, chemical processes in the, 103
---- straw, carbohydrates of, 105
Bleaching, 166
Bran, digestion of, 139
Brommethylfurfural, 8, 84, 86
Carbohydrates, action of hydrogen bromide on, 86;
action of hydrogen peroxide on, 114;
nitrated, as food for mould fungi, 43;
nitrates of, 41;
quantitative separation of, 96
Carbohydrates of barley straw, 105;
of wheat, 137;
of yeast, 113
'Caro's reagent,' 118
'Celloxin,' 71
Cellulose, alcohol from, 146;
constitution of, 77, 92;
fermentation of, 76;
industrial uses of, 155;
iodine reaction of, 21;
methods for the estimation of, 3, 4, 16, 19, 97;
nitration of, 43;
saccharification of, 73;
ultimate hydrolysis of, 11;
volatile acids from, 145
---- acetates, monoacetate, formation of, 40;
tetracetate, constitution of, 80
---- benzoates, 34;
from structureless cellulose, 36;
from three varieties of cotton, 35;
monobenzoate, properties of, 36;
dibenzoate, properties of, 37;
acetylation of, 130;
nitration of, 38
---- derivatives, commercial aspects of, 171;
saccharification of, 73
---- nitrates, 44, 45, 83;
structureless, 45, 51;
cupric reducing power of, 73;
instability of, 50, 53
---- sulphocarbonate, 27;
effects of the nature of the cellulose, 28;
---- ---- solutions, analysis of, 32;
iodine reaction of, 33;
loss of carbon bisulphide, 33;
viscosity of, 30
Cell-wall constituents, 97
Cereal celluloses, 101, 105
Chitin, 112
Chlorination, Cross and Bevan's method, 19;
statistics of, 134
Chloro-lignone, 126
Collodion. _See_ Silk, artificial
Cotton, lustreing effect of mercerisation, 23;
mercerised, structural properties of, 25;
pentosane content of, 148
'Crude fibre,' 17
Cuprammonium solvent, 21, 58, 173
Currants, pectin of, 152
Denitration of collodion silk, 56;
of jute nitrate, 133;
products of, 74
Dioxybutyric acid, 71
Elder pith, 137
Eriodendron, seed hair of, 92
Explosives, 44;
sporting powders, 52
Fermentation of cellulose, 76;
of furfuroids, 108;
of sugar from wood, 148
Fibres, report on miscellaneous, 139
Flax boiling, 168;
spinning, 161
Fodder plants, pentosanes of, 122
Fungi, tissue constituents of, 109
Furfural from cellulose, oxycellulose, and hydrocellulose, 70;
derivative from laevulose, 8;
estimation as hydrazone and phloroglucide, 119, 121;
oxidation of, 114, 118 (_refer also_ 'Pentosanes')
Furfuroids, 8, 10, 102, 105;
assimilation of, 108
Gabriel's method of cellulose estimation, 18
Gluconic acid, action of hydrogen peroxide on, 117
Glucosamin, 112
Hemicellulose, 96, 97;
determination and separation of, 100
Hoenig's method of cellulose estimation, 18
'Hydralcellulose,' 68
Hydrocellulose, 73;
nitration of, 43
Hydrogen peroxide, oxidations with, 114
Hydroxyfurfural in lignocellulose, 9, 116, 118
Incandescent mantles of artificial silk, 14, 15
Industrial appliances of cellulose, 155
Iodine reaction of cellulose, 21
Isosaccharinic acid, 71
Jute, composition of, 141;
quality of, 140;
treatment of, 142 (_refer also_ Lignocellulose)
---- acetate, 129
---- benzoate, 127;
acetylation of, 130;
nitration of, 132
---- nitrate, 131
Ketoses, physiological importance of, 9
Lange method of cellulose estimation, 18, 98
Lead compounds of nitrated carbohydrates, 49
Lignin, 100
Lignocellulose, constitution of, 133;
esters of, 125;
hydroxyfurfural in, 9;
new type of, 135
Lignone complex, properties of, 126
'Lignorosin,' 151
'Lustra-cellulose.' _See_ Silk, artificial
Malt, pentosanes of, 122
Mather system of boiling textiles, 167
Mercerization, 22; shrinkage during, 24
Mercerised yarn, strength and elasticity of, 25, 26
Methylhydroxyfurfural, 84
Mould fungi, nitrated carbohydrates as food for, 43
Mycosin, 113
Nitrated carbohydrates, lead compounds of, 49
Nitrates of carbohydrates, 41
Nitrocellulose (_see_ Cellulose nitrates);
silk, 55
'Normal' cellulose, definition of, 27
Normal paper, 160
Oxycellulose esters, 72;
nitration of, 43;
researches on, 71, 72, 74;
_resume_ of properties, 94
Oxygluconic acid, 117
Paper, deterioration of, 155;
normal standard, 160;
pulp, spinning of, 169
Peat, constituents of, 154
Pectins, 151, 152
Pentosanes, 100, 109, 144;
constituents of cotton, 124;
constituents of fodder, 122;
estimation of, 121;
of seeds during germination, 124
'Permanent tissue,' 103
Phloroglucinol, 119, 121
Plant tissues, carbohydrates of, 96, 97, 99
Plants, source of unsaturated compounds in, 145
Powders, manufacture of sporting, 52
Saccharification of cellulose and derivatives, 73
Schulze method of cellulose estimation, 18, 98
Schweizer solution, 101
Seeds, pentosanes in germinating, 124
Silica in plant tissues, 13
Silk, artificial, 54, 62, 63, 172;
bibliography of, 60;
from cuprammonium, 58, 64, 173;
from nitrocellulose (collodion), 55, 63, 172;
from viscose, 59;
from zinc chloride, 59;
reactions of, 64
---- natural, reactions of, 64
Straws, 101, 105
Succinic acid from furfural, 118
Sulphite waste liquors, 149, 164
'Swedish' filter paper, 14
Tissue constituents, 99, 109
Trees, composition of trunk woods, 142
Viscose and viscoid, 157, 158, 159
---- silk, 59, 175
---- ---- specific gravity of, 34 (_refer also_ Cellulose
sulphocarbonate)
'Vulcanised fibre,' 20
Weende, method of cellulose estimation (crude fibre), 17, 98
Welsbach mantles, 14;
Clamond type, 15
Wheat grain, insoluble carbohydrates of, 137
Wood, alcohol from, 146, 148
Wood-cellulose, waste liquors, 149
Wood-gum, 144
Wood-pulp, processes, 162
Wood, trunks of trees, 142
Yeast, carbohydrates of, 113
Zinc chloride, artificial silk, 59;
solvent action of, 20