Impregnating Paper and other Fibrous Materials.
Year: 1891

page_text: Date of Application, 20th June, 1891
Complete Specification Left, 21st Mar., 1892-Accepted, 23rd Apr., 1892
PROVISIONAL SPECIFICATION.
Impregnating Paper and other Fibrous Materials.
I, WILLIAM RIGHTER COMINGS, Mechanical Engineer of Brewhouse Yard,
172 St. John Street Clerkenwell, London, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
:-
My invention relates to a process or method of impregnating with suitable
substances paper or other fibrous materials, and it is particularly adapted to the
treatment of thick sheets and to articles made up of a number of layers of material
such as rolled paper tubes, boxes, coils or other articles.
My invention consists broadly in immersing the material while comparatively
cold in a bath of the impregnating solution raised to a temperature somewhat above
the boiling point of any moisture contained in the paper or other fibrous materials.
The action of this degree of heat in the bath expels the air and converts the
moisture contained in fibre of the material into steam or vapour, which with
the air rises to the surface of the bath and makes it boil or froth according to
circumstances. The heat is next turned off from the bath and its temperature
allowed to gradually fall. When it has dropped to about the boiling point of the
moisture, the bubbling ceases and as the heat decreases the atmospheric pressure
acts to force the liquid from the bath into the pores of the material to fill the
vacuum spaces left by the escape of the air and steam or vapour driven off during
the first or expulsion part of the process.
The second or absorption part of the process is continued till the impregnating
liquid has been drawn thoroughly into the pores and through the fibre of the
material, when it is removed and allowed to dry either naturally or in the air.
By suitably regulating and controlling the heat of the bath, the duration of both
the expulsion and absorption stages can be relatively prolonged, shortened or
equalized according to the particular requirements of each case, and the range of
temperatures for each stage can also be modified within large limits, according as
the saving of time or the cost of heating is the desideratum; thus, if the expulsion
stage is worked from 300° down to 212° the result can be accomplished quickly;
while, if worked say from 220° to 200° it will be proportionately slower, also if
the absorption process has a long slow run it will be more thorough and effective
than a short quick one. The process may thus be practically compared to the
action of squeezing a sponge in water and then by removing the pressure allowing
it to fill naturally.
For consolidating the fibre and smoothing the surface, I sometimes add when
required a third or finishing stage to the process which consists in submitting the
material (preferably while hot from the bath) to the action of heavy pressure, by
means of suitable rollers or dies, heated or otherwise.
In working this impregnating process practically I find by experiment that a
convenient way of carrying it out is to have the bath connected with independent
sources of heating and cooling, so that they can be gradually or instantly turned
on or off at will. One method of carrying this out is to surround the bottom and
sides of the bath with a steam tight jacket which can be supplied at will, either
with a heating current of steam or a cooling current of air or water, the air may
be supplied by an exhaust fan or blower.
For certain requirements I prefer to use a compound coating which is obtained
by first impregnating the article with a material comparatively thin, that will
penetrate the fibre easily and thoroughly fill up the pores, afterwards, a second
coating of a thicker material may be used to impart strength & finish to the
surface, or a second coating of the same material as the first may accomplish the

page_text: result, by allowing the tube to cool after its first treatment and then giving it a
quick dip.
Among materials which can be conveniently used for impregnating paper &
similar materials, for the purpose of giving them waterproof & insulating qualities,
I may mention such substances as paraffin, ozokerit, pitch, bitumen, & resin.
These can be used either simply or in mixtures or solutions, besides these a large
variety of other substances or materials could be used according to the requirements
of particular cases.
1001
WM. R. COMINGS.
COMPLETE SPECIFICATION.
Impregnating Paper and other Fibrous Materials.
I, WILLIAM RIGHTER COMINGS of Brewhouse Yard, 172 St. John Street,
Clerkenwell, in the County of Middlesex, Mechanical 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 :-
My invention relates to a process or method of impregnating with suitable
substances paper or other fibrous materials, and it is particularly adapted to the
treatment of thick sheets, and to articles made up of a number of layers of material
such as rolled paper tubes, boxes, coils or other articles.
Broadly stated my invention consists in utilizing the pressure of the air or power
vacuum to cause the impregnating substance to completely fill the pores in the
material treated. To this end propose to immerse the material while com-
paratively cold in a bath of the impregnating solution, raised to a temperature
somewhat above the boiling point of any moisture contained in the paper or other
fibrous materials to be treated. The action of this degree of heat in the bath
expels the air and converts the moisture contained in the fibre of the material into
steam or vapour, which with the air rises to the surface of the bath and makes it
boil or froth according to circumstances. The heat is then turned off from the
bath and its temperature allowed to gradually fall. When it has dropped to about
the boiling point of the moisture the bubbling ceases, and as the heat decreases the
atmospheric pressure acts to force the liquid from the bath into the pores of the
material to fill the spaces therein left by the escape of the air and steam or vapour
driven off, during the first or expulsion part of the process.
The second or absorption part of the process is continued till the impregnating
liquid has been forced or drawn thoroughly into the pores and through the fibre of
the material which is then removed and allowed to dry either naturally in the air,
or the drying may be artificially hastened.
Thus
By suitably regulating and controlling the heat of the bath the duration of both
the expulsion and absorption stages can be relatively prolonged, shortened or
equalized according to the particular requirements of each case, and the range of
temperature for each stage can also be modified within large limits, depending
upon whether the saving of time or the cost of heating is the desideratum.
if the expulsion stage is worked from 300 degrees F. down to 212 degrees F., the
result can be accomplished quickly, while if worked say from 220 degrees to
200 degrees F. it will be proportionately slower owing to the necessity of
thoroughly driving off the moisture prior to the temperature falling below the
boiling point of same, but if the absorption process has a long slow run it will be
more thorough and effective than a short quick one.
For consolidating the fibre and smoothing the surface I sometimes add when
required a third or finishing stage to the process which consists in submitting the
material (preferably while hot from the bath) to the action of heavy pressure by
means of suitable rollers or dies heated or otherwise.

page_text: In working the process I find by experiment that a convenient way of carrying.
it out is to have the bath connected with independent sources of heating and
cooling, so that they can be gradually or instantly turned on or off at will. One
method of carrying this out is to surround the bottom and sides of the bath with a
steam tight jacket which can be supplied at will either with a heating current of
steam or a cooling current of air or water, the air for this purpose may be supplied
by an exhaust fan or blower.
For certain requirements I prefer to use a compound coating which is obtained
by first impregnating the articles with a material comparatively thin that will
penetrate the fibre easily, and thoroughly fill up the pores, afterwards a second
coating of a thicker material may be used to impart strength and finish to the
surface, or a second coating of the same material as the first may accomplish the
result, by allowing the first to cool after its first treatment and then giving it a
quick dip.
Among materials which can be conveniently used for impregnating paper and
similar materials for the purpose of giving them waterproof and insulating.
qualities are such substances as paraffin, ozokerit, pitch, bitumen, and resin.
These can be used either singly or in mixtures or solutions. Besides these a large
variety of other substances or materials may be used according to the requirements
of particular cases.
As an example it may be stated that when using, say pitch, good results may be
attained by first heating the bath to a temperature of about 350 degrees F., then
immersing ordinary paper tubes of say inch thickness therein, and at once.
reducing the temperature of the bath until within, say half an hour it reaches
about 180 degrees when the tubes may be removed and allowed to dry. It will of
course be evident that while the temperature of the bath must be sufficient to keep
the impregnating substance sufficiently liquid to allow it to enter the pores, still
such temperature must not be so great as to char or burn the material being treated.
The proper temperature for different substances can readily be determined by a few
experiments.
It may sometimes be advisable to artificially moisten the material to be treated
before immersing it in the bath, such moisture causing the pores to open, and
when expelled in the bath leaving the material in a good condition to take up the
impregnating substance.
Having now particularly described and ascertained the nature of my said inven-.
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improved process of impregnating paper and other fibrous materials
which consists in utilizing the pressure of the air or power of vacuum to cause the
impregnating substance to enter the pores of the material treated, substantially as
described.
2. The improved process of impregnating paper and other fibrous materials
which consists in immersing such materials while in a comparatively cold state in a
bath of the impregnating solution, expelling the moisture and air contained in the
materials by the heat of the bath, and subsequently reducing the temperature and
utilizing the atmospheric pressure for the purpose of causing the impregnating
solution to enter the pores of the material being treated, substantially as described.
3. The improved process of impregnating paper or other fibrous material, which
consists in first impregnating the material by submitting it to the action of an
impregnating bath, and subsequently, preferably while in a heated condition,
submitting it to the action of heavy pressure by means of suitable rollers or
otherwise, substantially as set forth.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Applicant's Agent.