Improvements in the Manufacture of Artificial Silk from Suitable Forms of Cellulose.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Artificial Silk from Suitable
Forms of Cellulose.
We, WILLIAM PORTER DREAPER, of Clifton Villa, Coggeshall Road, Braintree,
in the County of Essex, Chemist, and HARRY KNEEBONE TOMPKINS, of North View,
Paget Road, West Dulwich, in the County of Surrey, Chemist, do hereby declare
the nature of this invention to be as follows:
Our invention relates to the production of silk-like effects by the combination
of a number of fine fibres made from cellulose which has been dissolved in zine
chloride with or without the admixture of other salts, and subsequently squirted
into a suitable solvent for the zine chloride which will also precipitate the dis-
solved cellulose in the form of threads.
It being essential for the purpose to have a number of very fine threads, to
squirt which at comparatively low pressures it is necessary to apply heat to the
jets, and it being impossible to wind and work with such fine threads separately,
we combine and twist them together to form one compound thread immediately
they are squirted, and before or during winding, thus securing the necessary
brilliancy and softness, and giving it sufficient strength for winding and subse-
quent treatment.
The subsequent treatment consists of washing, dyeing, drying and waterproof-
ing. The dyeing is performed by the means of silk or ordinary cotton dyes or
lakes, preferably before drying, or the dye or lake may be added to the dissolved
cellulose, and the drying must be performed while the threads are on the winding
drums or otherwise in a stretched condition. Waterproofing may be performed
either before or after drying.
hi Thirtieth day of July 1897.
W. PORTER DREAPER.
HARRY KNEEBONE TOMPKINS.
Improvements in the Manufacture of Artificial Silk from Suitable
Forms of Cellulose.
We, WILLIAM PORTER DREAPER, of Clifton Villas, Coggeshall Road, Braintree,
in the County of Essex, Chemist, and HARRY KNEEBONE TOMPKINS, of North View,
Paget Road, West Dulwich, in the County of Surrey, Chemist, do hereby declare
17

page_text: 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 the production of silk-like effects by the squirting and
spinning of a number of very fine fibres made from cellulose which has by known
means been dissolved in zinc chloride or other suitable zinc salts having an equiva-
lent hydrolising re-action, or a mixture of them, with or without the addition of
up to five per cent. of suitable salts of the alkaline earths such as calcium chloride,
and subsequently squirted into a liquid such as alcohol or acetone, which will pre-
cipitate the cellulose in the form of a continuous fibre, and dissolve the re-agents.
The salts of the alkaline earths are added for the purpose of controlling the dis-
solving of the cellulose and of strengthening the fibres.
In squirting the finest fibres we find it necessary to heat the cellulose solution
until it is sufficiently fluid at the moment of squirting, and this we do by applying
heat by means of steam or hot water jackets or coils to the jets through which the
dissolved cellulose is forced.
It being impossible to wind and work with very fine fibres separately, we squirt
them in groups and combine or twist the fibres of each group together to form one
compound thread immediately they are squirted, and before or during winding,
thus securing the necessary brilliancy and softness for use in place of soft or
"boil off" silk that is silk from which the natural gum has been removed and
giving it sufficient strength for winding and subsequent treatment.
The subsequent treatment consists of washing, dyeing, drying and water-
proofing.
The complete removal of the re-agents is necessary, and may be effected by
further washing in the precipitating liquid or in water or both. This may be
effected either while on the drums or winders or in the hank after being removed
therefrom.
To obtain the best results it is necessary that the fibres be dried while in a con-
siderably stretched condition. We therefore stretch the hank while wet to about
one & a half times its length by suitable means such as weights & prevent its
contraction while drying.
They may be dyed or waterproofed by any of the methods usual in the treat-
ment of cotton or silk and woven or otherwise treated alone or with fibres or threads
of other materials to make the required fabrics.
We find, however, that it effects a considerable saving to produce dyed fibres
by using cellulose already dyed or by the addition of suitable dyes or lakes to the
dissolved cellulose before squirting. By this means we obtain results more uniform
than are possible when dyeing in the hank, and by experience we can tell exactly
how much dye or lake is necessary to produce the required tint in the finished fibre.
We find also that eventual water proofing may be effected by adding suitable
mediums to the dissolved cellulose, which will become more or less insoluble on
drying, or which may be rendered so by subsequent suitable treatment. For
instance, gelatine may be added to the solution, and afterwards rendered insoluble
by any of the well-known methods.
It being necessary for the purpose of economical working to recover the spirits
and solvents, we distil off the spirit from the washing and precipitating liquors
at as low a temperature as possible to prevent decomposition of the spirits, which
is greater the higher the temperature of distillation.
When zinc chloride is used we then heat the residual liquor in an open vessel
until it boils at a temperature of 140° C. We then add a solution of zinc or
barium chlorate gradually until the organic matter is oxidised. To remove the
barium we precipitate it in the form of sulphate and remove by settling or filtra-
tion. Or the oxidation may be effected by passing chlorine through the liquor.
The solution of zinc chloride is then ready to be used again.
When zinc bromide and iodide are used we employ an equivalent treatment.
When zinc nitrate is used we then evaporate the residual liquor to dryness, and

page_text: heat the residue to a sufficient temperature to completely oxidise the organic
matter.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:
1. The manufacture of silk-like threads by dissolving cellulose in suitable zinc
salts, with or without the admixture of suitable salts of the alkaline earths, squirt-
ing the solution through groups of fine holes into a liquid which will precipitate
the cellulose in the form of continuous threads or fibres and twisting or bringing
together the fibres in each group to form compound threads suitable for use in
place of soft or "boil off" silk substantially as described.
2. In combination with the manufacture of silk-like threads from cellulose
substantially as described the production of dyed threads by using cellulose
previously dyed, or colouring the cellulose solution by the addition thereto of suit-
able dyes or lakes.
3. In combination with the manufacture of silk-like threads from cellulose sub-
stantially as described the addition of suitable mediums to the dissolved cellulose,
which will become more or less insoluble on drying or on subsequent treatment.
4. In combination with the manufacture of silk-like threads from celluloso
substantially as described the application of heat to the cellulose solution at the
moment of squirting.
5. In combination with the manufacture of silk-like threads from cellulose sub-
stantially as described the drying of the fibres or threads while in a considerably
stretched condition.
6. In combination with the manufacture of silk-like threads from cellulose the
recovery of the spirits by distillation and of the solvents by partially or wholly
evaporating the residual liquors and oxidising the organic matters substantially
as described.
Dated this 20th day of Auril 1898