Improved Process of Making Paper Pulp Boards or Paper in Imitation of the Grain, Knots, or Burls of Natural Woods.
Year: 1894

page_text: Date of Application, 17th July, 1894-Accepted, 20th Oct., 1894
¿COMPLETE SPECIFICATION.
Improved Process of Making Paper Pulp Boards or Paper in
Imitation of the Grain, Knots, or Burls of Natural Woods.
I, WILLIAM NORRIS CORNELL, a citizen of the United States and residing at
Brownville, in the County of Pulaski and State of New York, one of the United
States of America, Paper 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:-
My invention relates to an improved process of making paper pulp boards or
paper in imitation of the grain, knots or burls of natural woods.
In carrying out my improved process I can make use of any well known paper
or wood pulp machine without making any changes or additions thereto whatsoever.
My improved process can be carried out economically and requires no special
skill or knowledge on the part of operator.
In describing my improved process, I propose to first refer to a cylinder wood
pulp machine. Such a machine is provided with a vat in which the pulp is placed.
In said vat is mounted a making cylinder and above said making cylinder passes
the web or felt of the machine, said web or felt extending over rollers in the
usual way and having suitable mechanism for applying the necessary tension
thereto. The said web or felt passes between the two press rolls of the machine
which are pressed together by means of weights or other mechanism.
The making of wood pulp boards on such a machine is well understood by all
familiar with the art and is substantially as follows: The making cylinder takes
up out of the vat a thin film or layer of the pulp which is passed on the web or
felt of the machine. By the web or felt this film or layer of pulp is carried down
between the two press rolls, by means of which, or by means of the ordinary
couch roll or vacuum box, or all of these three elements, it is relieved of its
water. This thin film or layer of pulp is then taken up by the upper press roll
and is allowed to wind convolutionally thereon, until a board of the requisite
thickness is obtained. The pulp is then removed from the upper press roll in any
suitable way, such as by means of an ordinary knife now used for that purpose.
A wood pulp or paper pulp board is now obtained of the requisite thickness and
having a length equal to the circumference of the upper press roll, as will be
understood. The board is then flattened out, dried, calendered, sand-papered and
in some instances varnished and otherwise finished and is then ready for the
market.
In carrying out my present process with such a machine when it is desired to
imitate the grain of wood, I proceed substantially as follows: Let it be supposed
that a wood pulp board is to be obtained thirty inches wide, that being the width
of the making cylinder and having a thickness of forty laps or layers of the pulp
on the upper press roll, said board being of a length equal to the circumference of
the upper press roll, as in all such machines.
I first dye the pulp in the vat by any suitable animal or mineral dyes or
pigments of the color of the wood which is to be imitated. I then start the machine
and allow, for instance, ten laps or layers of the pulp to be taken up by the upper
press roll.
I then take a separate sheet of pulp and tear it in an irregular form,
which is, let it be supposed, not more than fifteen inches wide at its widest portion

page_text: and being not longer than the circumference of the upper press roller. I will
suppose this separate piece of pulp has a thickness equal to fifteen laps or layers
of the pulp on the upper press roll. This separate piece of pulp, which should
either be drier than the pulp on the upper press roll or which should have a
greater density than the same, but should not be absolutely dry and hard like a
finished board or sheet is placed on the center or about on the center of the pulp
which has been wound on the upper press roll, and is taken up thereby and wound
on the roll with the pulp from the vat, so that the separate piece at its widest
portion will be seven and one-half inches from each side of the pulp on the upper
press roll. It will now be seen that that portion of the pulp on the upper press
roll coincident with the separate piece which was introduced thereon, is equal to
twenty-five laps or layers thereon, whereas at each side of said separate piece the
pulp on the upper press roll is equal to only ten laps or layers thereon. The
greatest pressure is therefore brought to bear on the thickest portion of said
piece of pulp and the tendency of the press rolls is to crush said thick portion
down so as to make the pulp on the upper press roll of even thickness throughout.
This uneven pressure causes the pulp on the upper press roll and particularly the
thick portion of the pulp thereon, to separate and slip so as to form wrinkles and
ridges therein, which wrinkles and ridges extend through the board. The machine
is allowed to operate until the desired thickness of the pulp on the upper press
roll is obtained and by such time the effect of the press rolls has been to bring the
pulp down to an even thickness throughout.
The pulp board is then removed from the upper press roll in the usual way.
The board is then dried and may be calendered or not. After the calendering
of the board or after the drying if the board is not calendered, one or both sides
thereof is suitably sand papered so as to efface the wrinkles and ridges which are
formed therein and make the board perfectly smooth. When this is done it will
be found that there is left on the board a perfect representation of the grain of
wood, as I have found by experiment. After the sand-papering of the board, the
smooth. surface is finished in any suitable way, such as by varnishing and
polishing.
The adaptability of this new and improved process to paper machines of the
Fourdrinier type will be obvious. In such machines paper boards cannot be made
of the thickness as in the cylinder machines of the type referred to above. In
Froudrinier machines the pulp is taken up from the vat and is run on to a making
apron or wire by which it is shaken so as to be distributed in a perfectly even
manner, so as to have an even thickness throughout. It is then carried over a
vacuum box by which a large percentage of the water is extracted therefrom.
The sheet is then carried through couch rolls whereby a certain degree of solidity
is imparted thereto and from which it passes onto an endless blanket or felt. The
sheet is carried by this blanket or felt between press rolls which press the paper
and from thence over heated calendering rolls and then over other press rolls and
calendering rolls until the sizing material thereon has become thoroughly
incorporated. It is then allowed to accumulate on a reel until the desired quantity
has been obtained.
In carrying out my process with a machine of this type, I mount a separate reel
or roller between the first press rolls and the couch rolls of the machine and I place
on this reel a sufficient quantity of pulp in a continuous sheet having a greater
density than the pulp on the machine before it reaches the press rolls, or being
drier thau said pulp, as I use it in cylinder machines. This separate pulp in a
continuous sheet is of less width than the pulp which has before formed in the
machine, as in the other machines, and it is torn or otherwise formed in an irregular
shape.
The machine is now started and the pulp is taken up on the making web and
passes between the couch rolls to the press rolls. At the moment this pulp enters
the press rolls the separate continuous sheet of pulp on the reel before mentioned is

page_text: press rolls
ntroduced on the press rolls with the other sheet and is carried through the
nachine therewith. The presence of this separate continuous strip or sheet of pulp
n the machine has precisely the same effect as when applied to a cylinder machine,
hat is to say, it causes the sheet of pulp to slip and wrinkle between the
and thereby forms an accurate presentation of the grain of wood as is well known
and as has been before explained. Wood pulp or paper pulp cannot be made of
any great thickness on a Froudrinier machine, but it is possible by means of my
process when applied thereto to make paper, such as wrapping paper or writing
paper with an uneven grain in close imitation of natural wood.
In carrying out my improved process with a cylinder machine for the imitation
of burls and knots, I proceed substantially as follows: The pulp is colored and is
allowed to wind on the upper press roll as before explained, until the desired
number of laps have been formed thereon. I then take small separate pieces of
pulp having a greater density or being drier than the pulp on the press roll and
being of a darker color than the pulp on the press roll, and allow such small pieces,
at proper distances apart, to be wound up on the upper press roll with the pulp
thereon. These small pieces are of irregular shape and may be for example, from
one to three inches across the widest portion. These small pieces of pulp act in
precisely the same way as before explained and in flattening out cause the pulp on
the press roller to become wrinkled or ridged directly adjacent to said small pieces.
The pulp board is then removed from the upper press roll and is dried or calendered
as before. This sand-papering process is carried on until the small separate pieces
of pulp show on the outside and these being of a darker color than the base of the
sheet, will show up in irregular lines in close imitation of burls or knots. The
board is then finished by varnishing or polishing in the usual way.
The introduction of these small separate pieces to the pulp on the cylinder
machine may be carried on with or without the separate piece before explained for
the imitation of the grain of wood, and it will also be understood that when only
the grain of the wood is to be imitated, that the single irregular piece which is
allowed to wind up on the press rolls may be colored to a darker color than the
wood similar to the small separate pieces which are wound thereon when burls and
knots are to be imitated.
Having now described and ascertained the nature of my said invention and in
what manner the same is to be performed, I declare that what I claim is :—
1. An improved process of making paper pulp board in imitation of natural wood,
which consists in winding convolutionally on a paper machine a pulp board of less
than the desired thickness, then in adding a separate piece or pieces of pulp to the
partially finished pulp board and finally in finishing the winding of the pulp board
to the desired thickness, whereby said separate piece or pieces of pulp cause the
pulp board to slip and wrinkle on the forming roll, substantially as set forth.
2. An improved process of making pulp board in imitation of natural wood,
which consists in winding convolutionally on a paper machine, a pulp board of less.
than the desired thickness, then in adding to the partially finished pulp board a
separate piece or pieces of pulp of greater density or drier and of another color
than the pulp board and finally in finishing the winding of the pulp board to the
desired thickness, whereby the said separate piece or pieces of pulp cause the pulp
board to slip and wrinkle on the forming roll, substantially as set forth.
3. An improved process of making pulp board in imitation of natural wood,
which consists in winding convolutionally on a paper machine a pulp board of less
than the desired thickness, then in adding to the partially finished pulp board a
separate piece or pieces of pulp of greater density or drier and of a darker color
than the pulp board; then in finishing the winding of the pulp board to the desired
thickness, whereby said separate piece or pieces of pulp cause the pulp board to
slip and wrinkle on the forming roll then in removing the pulp board from the

page_text: machine and finally in drying, sand papering and finishing said pulp board, sub-
stantially as set forth.
Dated the Sixteenth day of July 1894
WILLIAM N. CORNELL,
By W. Fairburn-Hart,
Agent.