Патент USA US2402554

June 25, 1946.
F, A IRVINE HAL
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‘ 2,402,554
MOLDED PRODUCT AND METHOD OF MAKING
Filed May 25', 1956
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2,402,554
' Patented June 25, 1946
UNITED STATES PATENT OFFICE
2,402,554
MOLDED PRODUCT AND METHOD OF
MAKING
'
Fergus A; Irvine and Emile Frederick, Jr., New Or
‘leans, La., asslgnors to The Celotex Corporation,
Chicago, 111., a corporation of Delaware ‘
Application May 25, 1936, Serial No. 81,605
16 Claims. (0]. 18-475)
1
2
The primary object of this invention is the pro
molded product as a single stage process of man
ufacture and thereby avoid what, in ‘connection
with this invention, are unnecessary steps in the
vision of a new and improved molded product
and method of producing such products directly
from cellulosic ?bers as the primary material _
without the addition of added hinder or binder 5
process of manufacture.
.
According to the invention, the basic or raw
material utilized in the process is a substantially
forming substances. It is proposed, according to
the inventions disclosed herein, that by following
raw or natural cellulosic ?ber such as the ?ber
the processes herein described, there may be man
of sugar cane, corn stalks, wood ?ber (the ?ber ‘
ufactured hard, dense, and strong products which
of trees), and others of the cellulosic ‘?bers conresult fromre-actions involving only the sub 10 taining the natural substances of growth which,
stances of the cellulosic ?bers comprising the raw
for want of a more speci?c designation, are ordi
materials hereof, brought about through the par
narily referred .to as ligno-cellulose ?bers. Ac
ticular processes of manufacture as hereinafter
cording to the basic process hereof, these ?bers
described.
.
.
‘
are utilized in substantially‘their natural state
Other and further objects of the inventions 15 with ‘only su?icient preliminary preparation as
hereof are the provision of various forms and
modi?cations of the process, illustrating to at
may be necessary to disintegrate the‘ raw material
into a particle or ?brous form of the ?neness
least a limited extent the possibilities of the - required to produce a ?nished article of the de—
process and of the product disclosed.
sired ?nished characteristics as regards the form
Further as objects of theinvention hereof there 20 or shape thereof and degree of physical structure
are included many and various modi?cations and
as regards density, surface appearance, and the
variations of the basic product hereof comprising
like. For a‘ dense product it will be necessary
products produced by modi?cation of the basic
that the raw material be quite ?nely sub-divided,
raw material by the admixture of additional re
whereas, on the other hand, if the ?nished ma
active or extending substances thereto and by 25 terial need not be of as high density, and some
degree of surface irregularities is permissible,
various admixtures of modifying and additional
substances with the basic raw material.
then the raw material need not be so ?nely sub
Within the past few years there has grown up
divided and may be proportionately relatively
an extensive industry in connection with the
coarse.
manufacture of synthetic resins and synthetic 30 The raw material is used in its form in which
resin products, which resins may generally be
~ it is produced by nature except insofar as it is
altered in the steps of disintegration into particles
which molded products may be generally de
for use in accordance with the process hereof.
scribed as generally comprising combinations of
As an example, sugar cane ?ber utilized as ba
such synthetic resins including more or less ?ller 35 gasse, or the refuse fiber from the sugar mills
after the vextraction of sugar, may advantageously
and/or reinforcing material such, as wood ?ber,
be softened by a, short period of digestion with
paper ?ber, paper, cloth, cotton ?ber,‘ asbestos,
and the like. This synthetic ‘resin development ' water as; for example, by digestion in water at .'
began primarily in connection with the phenol
about 40 lbs. steam pressure for a period of one
formaldehyde type resin and has subsequently de 40 to two hours, which digestion merely serves to
veloped to include many other types of condensa
soften the ?ber but in the course of which there
tion resins including the furfural resins, the urea
will be removed from the ?ber a large proportion
resins, and the numerous types which are known
of the water solubles which arebut a relatively
to those skilled in the art and-much literature
small proportion of the total raw material. The
concerning which has been published.
45 bagasse ?ber which has been softened by the
In the past, the production of the products gen
digestion (really but a steaming) as described,
erally referred to as synthetic resin molded prod- >
may then be run through appropriate re?ning
ucts have involved at least three separate stages
equipment such as swing hammer shredders,
of manufacture; ?rst, comprising the manufac
Cla?in re?ners, and the like, which re?ning equip
ture of the synthetic resin polymerized to an 50 ment will reduce the material to a condition of
appropriate degree; second, comprising the com
more or less separated ?bers depending upon the
bination of the synthetic resin with the ?ller
degree of re?ning ‘to which the material is sub
jected. As distinguished from this manner of
material; and third, the molding of this mixture
of resin and ?ller. It is the particular object
sub-dividing the raw material as has been just
of this invention to produce a resin containing 55 described, and as an advantageous manner of
described as condensation reaction products and
3
2,402,554
preparing the raw materials in connection with
certain types of molding, the raw material may,
without the preliminary digestion or steaming,
be passed through appropriate grinding apparatus
4
gas or ?uid that may be circulated into and out
of supply and discharge pipes IS.
with the mold I l ?lled and the plate l0 and
ram l2 heated, in accordance with the above
to reduce the raw material to a particle form. of
a, more or less ?our-like character, which reduced
directions, and with the mold containing nothing
?oury or powdery material may be used in sub
above described, with its natural atmospheric
moisture content of substantially 7% to 11%,
pressure is then applied through the plungers 2|
sequent steps of the process.
By the use of the process of manufacture here
in disclosed, it becomes unnecessary in the man
ufacture of synthetic resin containing molded
products to ?rst prepare a synthetic resin and a
?ller material, which two substances are subse
but the prepared ?brous or ?oury material as
10 attached to plate Ill and ram [2 to compress the
material within the mold II, which pressure
should be preferably about 1,000 pounds per
square inch over the area of the ram face with
a minimum of around 500 or 600 pounds per
quently mixed and molded and, as distinguished
from such procedure, the process hereof discloses 15 square inch and an apparent practical maximum
a method of procedure wherein the product is
of about 1,500 pounds per square inch, although
produced by a single step operation.
apparently this stated maximum can be exceeded
In order that the process disclosed may be bet
without unfavorable results provided that the
ter visualized, and in order to illustrate in gen
desired characteristics of the materials used and
era] the type of apparatus which may be used, a 20 product desired require the use of such higher
diagrammatic-drawing accompanies this speci?
pressures and it is practical to apply such higher
pressures.
cation.
In the drawing:
The application of pressure to the material in
Figures 1, 2, 3, and 4 are diagrammatically
mold II, as above described, using fairly coarse
illustrative of an apparatusused in the practice 25 ?ber introduced to a density of about 0.25 to pro
of the invention, the successive ?gures being illus
duce a ?nal product of a density of about 1.0,
trative of successive steps in the process of pro
results in the compression of this material to a
duction of the molded product hereof.
relatively thin wafer form having a thickness
Figure 5 is a diagrammatic illustration of an
about one-quarter of the thickness of the mate
alternative form of the press apparatus illus 30 rial originally charged into the mold, thatis, if
trating a particular form of press seal.
the mold has charged thereto 1" of the ?brous
Figure 6 is a diagrammatic showing of a fur
or powdery material, the application of the pres
ther manner of press seal.
sure, as described, will result in compressing this
Figure 7 is a diagrammatic showing of a still
material to a thickness of about approximately
further type of press seal.
1A". This phase of the process is illustrated in
In the production of a molded product, in ac
Figure 3 wherein it is indicated that the ram I!
cordance with this invention, the raw material,
has entered into die I I to compress the substance
?brous cellulosic growth, such as sugar cane,
in the mold against the plate I 0 as is apparent
bagasse, corn stalks, wood, or other vegetative
from inspection of the drawing. With the heat
growth, may be, through softening by steaming 40 ing medium circulating through the plate and
and re?ning, grinding, or the like, reduced to a
ram, and with the applied pressure maintained,
powdery or ?brousstate and is charged into a
the compressed wafer is held subjected to such
mold II which, as illustrated, is designed to pro
conditions for a period of approximately 10 to 12
duce a wafer-like ?nal molded product.
minutes, whereupon, without other change of con
Mold II, when ?lled with the ?brous or pow 45 ditions, the internal gaseous pressure-within the
dery cellulosic substance, is closed by bringing
mold is slowly relieved until such internal gaseous
down thereon plate l0, as illustrated in Figure 2,
pressure is reduced to substantially atmospheric
which, as will be seen from inspection of the
pressure.
drawing, provides a mold ?lled with the cellulosic
Relief of the internal gaseous pressure within
material and sealed at the top by plate lil'and at 50 themold may be accomplished by release through
the bottom by ram l2. Both plate l0 and ram I!
a valve H provided in an outlet 13 which passes
are cored or otherwise provided with passages
through the plate ill to communicate with the
therethrough for the purpose of circulating a
interior of the mold, or it may be accomplished
medium which may pass in through one of the
by other appropriate means, as, for example, by
pipes indicated at 15 and out of the other pipe 55 a slow release of the compression pressure very
I5 which are provided as inlets to and discharge
gradually reduced over a period of several min
pipes from the cores or passages of the plate and
utes whereby the internal pressure may be slowly
ram. The heating medium may be any heated
substantially released from between the surface
?uid or gas which can be circulated through the
of the plate I0 and the top edge of mold ll.
cored portions of the plate and ram at su?lcient 60
When the internal pressure of the molded prod
temperatures to provide and maintain the desired
uct is substantially released as by allowing the
temperatures of the plate and the ram, which
gases to escape through pipe I: and valve H the
desired temperatures are those corresponding to
full press pressure is held during this period of
the temperatures of steam between the pressures
escape and for a short period thereafter, say, a
of 125 lbs. to 150 lbs., more or less, the extreme 65 minute or two, or on the other hand when the
range apparently being approximately between
internal pressure is allowed to escape by the re
the temperatures corresponding to steam pres
lease of the compressed pressure as described,
sures of 110 lbs. to 190 lbs., that is, temperatures
then upon the accomplishment of the substantial
of between about 345° to 395° F. While it has
release of the gaseous pressure the press pressure
been stated that substantially any circulating 70 up to the original full pressure is preferably re
medium may be utilized to supply the necessary
applied for a short period, say, two to four or
heat to the plate and ram, this is, of course, to
?ve minutes as this repressing produces a product
be quali?ed that such gas or ?uid must have a
having somewhat greater strength than one not
speci?c heat su?icient to supply the necessary
having the ?nal step of repressing applied. After
heat within the limitations of the amount of such 75 the release of the internal pressure and applica
2,402,564
5
tion of the repressing pressure as above described,
the mold may then be opened by the release of
the press pressure and on elevation of plate ID
the molded wafer formed in mold _|l may be
ejected by slight movement of ‘ram l2.
Attention is directed to the fact that during
’ the period of gas pressure release the press pres
sure must not be reduced at too high a rate since,
heated material various chemical reactions and
combinations which, in effect, insitu, within the
compressed material, produce chemical sub
stances which combine and condense 'to form a
binder of the synthetic resin type, as, for ex
ample, certain constituents may, by incipient or
actual distillation, ‘or other chemical reaction,
produce something of a phenolic type of sub
stance, and other ingredients of vthe mix may like
under such circumstances, the high pressure gases
formed within the compressed material, due to 10 wise create or produce aldehydic type substances,
which phenolic and aldehydic type substances
the heat and pressure applied, will, under such
condition of too rapid release of pressure, explo
then condense to form .a synthetic resin of the
sively disrupt the compressed material or will at
phenol-aldehyde type.
a‘
'
The explanation just given concerning what is '
least cause portions of the outer, surface of the
compressed material to raise as blisters and thus 15 believed to occur during the pressing-procedure
spoil the product.
,
is, although reasonably supported by various
analyses and experiments, stated merely as a
theory and it may be that the substances pro
duced and combined are neither of a phenolic
cerns the seal of the molding chamber, that is, 20 or aldehydic type, but nevertheless it isclearly
An essential feature in connection with the
apparatus above described and in the use thereof
in molding products in accordance herewith con
the top plate In must tightly ?t and seal the upper ‘
edge of the mold ll andplunger I 2 must have
a sealing ?t so that during the pressing period
the full gas and vapor pressure developed under
the conditions of the applied heat and tempera 25
evident for the reasons which have been stated,
that there is some reaction of this general nature
which results in the formation of a synthetic
resin type of binder material which is very
evidently distributed throughout and among the
remaining cellulosic portion of the molded prod
ture is retained and held.
In carrying out the molding process as above
uct, the cellulose content of the original mate
rial not being visibly acted upon or altered dur
described, it appears that there is a conversion of
ing the processing and remaining as ?lling and
‘the encrusting materials of the cellulosic ?bers
which materials, other than cellulose, commonly 30 reinforcing material in the ?nished product.
referredv to as lignins, comprise various speci?
In connection with the above described process,
the essential and controlling feature of the pro
cally unidenti?ed substances but known to com
duction of the desired ?nished product is that
prise in part carbohydrates and pentosans, and
during the primary pressing operation the gases
the like, but as stated, comprising largely un
identi?ed substances, generically referred to as 35 and vapors produced within the mass of sub
‘stance being pressed be retained within such
lignins. The product produced in accordance
mass. The theory in connection with this feature
with the above, under the conditions of pressure
of the process is that the reactions which pro
and temperature as above described, clearly
ceed within the compressed mass, under the con
shows upon inspection that while subjected to the
pressure and temperature conditions, ingredients 40 ditions of pressure and temperature of compres
,sion, occur only under conditions of high'pres
of the charged material have been converted into
sure, which high internal pressure within the
substances of the synthetic resin type and that
mass is provided by the gases and vapors retained
such resins formed in situ within the mix of the
within the mass when such gases and vapors are
cellulosic material, ?rmly adhere to cellulosic
particles into a hard, dense, and strong molded 45 formed and expanded in accordance with the
temperature conditions applied. If the mass be
product, of the synthetic resin bound type.
ing compressed is sealed during pressing so that
As indicative of the fact that there has been
the formed and expanded vapors and gases can
chemical changes in the ingredients during the
not escape, then there is an internal pressure,
pressing operation, benzol extractions have been
dependent upon the applied pressure and tem
made of the divided materials before pressing and
perature which is built up within and throughout
it has been found that there were benzol soluble
the compressed mass.
substances present in the amount of 1.9%, where
as the same materials, after pressing, show a
benzol soluble content of 3.3%, and further, after
molding as above described, it is absolutely im
possible to repulp the compressed material and
obtain ?ber or powdery substance at all similar
The high internal pressure built up within and
throughout the mass during compression, as
above discussed, is to be distinguished from the
mere pressure of compression which exerts on the
compressed mass only such pressure as is trans
mitted from particle to particle within the body
in form to the material originally charged into
thereof, which condition is Very different from
the mold. To repulp or attempt to break down
the molded material into its original form, it was 00 one wherein, due to entrapped and expanded
gases and vapors, a high internal pressure is built
necessary to break the molded material into small
pieces and to subject these plates to a severe . up within the mass,,including all the interstices
and voids between particles thereof.
_
steaming action, and even after such procedure,
The high internal pressure built up within the
a repulping or reducing action to which they were
subjected with the speci?c objectpof obtaining 65 interior of the mass is apparently essential for
the formation of the described resin type binder.
?brous or ?oury substances such as originally
charged into the moldywas unsuccessful in that
.A sheet of bagasse ?ber compressed underthe
the material was so bound together it could not
conditions as hereinbefore described, produces
be reduced to anything like the original form.
the resin bound product hereof whereas a like
While it is as yet impossible to prove, various 70 sheet of bagasse ?ber compressed under the same
experiments which have been carried on are be
conditions, except that the internal pressure
lieved to clearly indicate that, when raw mate
therein is not maintained as described, does not
rials such as have been above described are
show development of the resin bond and the
molded in accordance with the procedure de
product resulting has little or no strength and,
scribed, there proceed within the compressed and 75 in fact, is nothing but acompressed mass of ?ber.
2,402,554
Again as a theory only, but one which appears
to be borne out by facts discovered, it appears
that the gases formed in the ?ber mass when
subjected to the heat and pressure of pressing
and retained in the compressed mass as high
pressure gases act as a catalyst in the reactions
which occur or actually enter into the chemical
actions involved.
A clear indication that this,
theory is correct, though not fully understood, is
the conditions of pressure and temperature of
pressing as has been described.
,
I
In Figure 6 there is shown a modi?cation of
the form of apparatus shown in Figure 5 and in
which gasket I6 is replaced by a rather narrow
ridge or projection ll preferably formed on the
face of press plate ill, on the face itself if a sepa
rate press plate as mentioned is not used, or, in
the plate or attached thereto if a separate press
plate is used. Such'ridge or projection IT, as
the press closes, serves to super-compress that
indicated by the fact that if these gases are not
brought up to the high pressure and tempera
ture by sealing these gases in, the product does .
not show the resin bond.
indicated at 2 l, which super-compressed ?ber acts
A molded product made in accordance with the
above procedure from bagasse ?ber, having
from interior of the sheet being pressed. The
average normal moisture content of ‘ll/2%, had a
density of over 1.0 and tensile strength well in
?ber sheet adjacent to the edges thereof a narrow
excess of 3000 pounds per square inch.
strip of material or a wire or the like to serve the
Such
strength is extremely high, particularly consider
portion of the ?ber sheet l8 near its edges as
as a vapor and gas stop toprevent egress thereof
same effect may be achieved by placing on the ,
same purpose as the ridge or projection I‘! just
ing that such strength is derived from the rela 20 before described.
tively small part of the material which is, avail
Figure 7 shows a still further modi?cation of
able for and converted into the resinous binder.
the apparatus in which a screen, or screen-like
As alternative of actual molding, as described
member, 2| is secured to or mounted on press
in connection with the process illustrated in Fig
plate ill, with or without the interposition of a
ures 1 to 4 in which the material being compressed 25 separate press face plate. At the edges of the
is actually sealed in a mold, the pressing opera
screen there are provided edge seals 22, it being
tion may be otherwise carried out in different
understood that the screen is exaggerated in the
apparatus to achieve the same ?nal result, as will
illustration and that the seal members 22 serve to
be pointed out.
seal the material being pressed, as described in
To produce a ?at sheet of material, in accord 30 connection with seal members I6 and I1, Figures
ance with the invention hereof, having length and
-5 and 6.
breadth dimensions relatively great in proportion
' The screen 2| serves to produce a screen mark
to thickness, there may preferably be used appa
ing on a. surface of the ?nished product and it
ratus such as is indicated in Figure 5. In Figure
5 the plate It! remains a press plate, ram 12 be
comes a similar but opposed press plate and mold
H becomes a gasket indicated at l6; or otherwise
also serves to provide channels for quicker pas
sage of entrapped gases and vapors to the edges
for escape when the press pressure is released,
as will be understood.
»
stated, the apparatus comprises opposed press
When the members 2| are screen-like as men
plates l0 and i2 with a sealing gasket l6 provided
tioned, it is to be understood that like purpose
to form a seal during the pressing operation. 40 and effect may be achieved by the use of press
plates mentioned, having lines or ?gures on the
Plates I0 and I2 are each cored for heating fluid
surface, in relief .or intaglio, to correspondingly
with inlet and outlet pipes I5 and there is means
produce on the surface of the finished product
for applying press pressure as by plungers 20.
such pattern raised above the surface or pressed
The faces of plates I0 and I! may be the material
of the plates but it will, of course, be understood 45
.
therein.
.
While optimum conditions of manufacture
hereunder were particularly pointed out, it is to
be realized that between the limits mentioned
of stainless steel, blue annealed steel or any of
there will be a variation of characteristics of the
the alloys which will provide hard smooth surface
faces, or the faces may be appropriately plated or 50 molded product produced. In the range of the
lowest pressure and temperature mentioned, the
otherwise treated.
product
will be of a lower density, probably
To make a molded sheet prgduct in. accordance
around 0.8 and tensile strength will be down cor
with the invention hereof,"‘say§_;gf;jr .4'~ by $4,", the
respondingly to around. 1600 pounds per square
press plates, as shown in??rmg?'willbesome
what longer than the statedJdimensions, say 3' 4" 55 inch. In the upper range of pressure and tem~
perature conditions the product will probably be
to 6" by 4' 4" to 6". Theprepared material,
of a density approaching 1.2 and tensile strength
prepared as above described, conveniently in the
that for the pressure applying faces thereof, there
may be mounted thereon relatively thin sheets
approaching or exceeding 4000 pounds per square
inch. The ?gures just given apply to a molded
0.26, having normal atmospheric moisture content 60 product produced from a distinctly ?brous
bagasse. If the primary material is ?our-like
of around 8% to 9%, is placed between press
rather
than ?brous, it can usually be expected to
plates i0 and I2. Around the edges of the ?ber
pack somewhat more than ?ber, to produce
sheetthere is placed a gasket l6 which may be a
form of a sheet of ?ber insulation board about
3' 1" by 4' 1" by 1/2" thick, of a density about
strip of deformable material such as lead or soft 65 a slightly higher density product, which, because
without the reinforcement afforded by ?bers, is
copper, or the like, or which may be of hard ma
generally of lower tensile strength compared to
the product made from ?ber as the primary
material.
When pressure is brought on a sheet, such as
described, by closing the press plates, the soft 70 A very important feature, particularly in con
nection with practical use of the invention hereof,
board is quickly compressed to substantially the
although not of particular importance in connec
?nal thickness and the gasket [6 serves to seal
tion
with the basic invention hereof, is in that
the edges with the same effect as mold ll of Fig
much of the art and knowledge which has been
ure 1, to retain, in the material being compressed,
developed in connection with synthetic resin
the vapors and gases formed and expanded due to 76 molding
is generally applicable to the practice of
terial approximately the thickness of the ?nished
pressed product.
‘
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_
2,402,654
this invention. To the raw material as herein.
tion of a per cent of hexamethylene tetramine
before described, prepared as directed, there may
be added additional binder material if a?nal.
product containing a greater percentage of binder
than that formed in the simple practice of the 6
invention is desired. For example, there maybe
added to the disintegrated ?ber a percentage of
a phenol-formaldehyde resingpartially reacted, as
well known, or there may likewise be added a
percentage of other known resin forming combi 10
nations or polymerizing and oxidizing oils such
or aniline hydrochloride or of one of the other
various acid or alkali or alkali hydroxide or car
bonate catalysts such as are used in conventional
' as tung oil or linseed oil or the like.
Relatively small amounts, say from 2% to 5%
synthetic molding operations. or course these
various catalysts do not each produce equal re
sults in assisting in the resin formation during
compression but it appears that any of such cat
alysts do to at least some extent aid in the resin
formation.
>
The inventions hereof having been disclosed in
detail, we claim:
_ "
1. The process of‘ forming molded products
of added binders such as above described will pro
from a mass of ligneous cellulose ?bers having a
duce a greater relative increase in the strength 15 moisture content of between 5 and 15% which
of the ?nal product, asmay well be understood,
comprises the steps: compacting the mass by the
but in general the greaterthe amount of- such
application of pressure while the mass is sub
added binder added the greater will be the
jected to heat of 240 to 300’ degrees F., holding
' strength of the ?nal product.
The produce may, of course, be produced from
a single kind of fiber or there may be combined
a plurality of the raw materials, and further,
for the production of products having special
characteristics there may be admixed therewith
limited amounts of other ?bers, for example, rel
atively long vand tough ?bers such as ?ax ?ber,
or there may be admixed therewith ?ller mate
rials such as whiting, elaterite and other ?nely
,divided substances employed generally to impart
color to the ?nal product. Such. added ?ber or
?ller material cannot be used to too great a pro
portion, to 10% or in some cases up to about 20%
being apparently the upper limit. In case,
though, added binder is used, as has been de- ‘
scribed, the percentage of added ?ber or ?ller
can be increased. If added binder to the amount
of 10% is used, then added ?ber or ?ller up to
the mass so compacted and heated for a. period
of about 10 minutes to cause substantially com
plete polymerization of constituents of the mass
whereby a water insoluble resinous binder is
formed, and sealing the mass of ligneous cellulose
?bers while it is so subjected ‘to the heat and
pressure to retain the gases and vapors thereof
to cause substantially complete polymerization of
the' mass of constituents of ligneous cellulose
?bers.
2. The process of producing resinous products
from ligneous cellulose ?ber having a moisture
‘content of substantially 6 to 12% on the weight of
the dry ?ber, which comprises the steps: com
pressing the ligneous cellulose ?ber in a closed
chamber by a presure between the limits of sub
stantially 500 to 1500 pounds per square inch, and
heating the cellulose ?ber to a temperature be
tween the limits of 400° F., plus or minus 100° F.
about 20% to 30% is permissible.
"
to cause substantially complete resini?cation of
In making a product in accordance with-the
a constituent of the ligneous cellulose ?ber.
disclosure hereof it may be desired to obtain 40 .3. The process of producing resinous products
waterproofness of the ?nished product greater
from ligneous cellulose ?ber which comprises the
than normally provided by the process as de
steps: compressing'and'heating the ligneous cel
scribed. In such case the basic ?ber may be
lulose ?ber in the presence of‘ moisture in a closed
treated with an alum and rosin size, or a para?in
chamber, maintaining during resin formation" the
size, or tung oil size, or the like, as is understood
internal gas and vapor pressure produced within
in the paper and ?ber board industry, and in
the mass ligneous cellulose ?ber due to the heat
such case the application of waterproo?ng to the
applied, and slowly decreasing the internal gas
?ber willresult in a ?nal product having a higher
and vapor pressure substantially to atmospheric
degree of waterproo?ng than one produced from
?ber not so treated.
I
4. The process of forming molded products
It is to be understood that, as described, the
from ligneous cellulose ?bers having a moisture
sealing of the edge of the material being com
content of substantially 9% which comprises the
pressed is intended not necessarily to include a
steps: compressing and heating the ligneous cel
complete edge seal of the body of the material.
lulose ?bers in a mold causing the formation of
‘ The seal to be considered is such seal as described,
vapors,
restraining the vapors formed within the
which, under the circumstances, will accomplish
mold, subjecting the vapors formed to the heat
the desired results. For example, in molding a
and pressure during-a period of resin formation,
relatively small disc, rather thick, a complete edge
-and releasing the pressureslowly with simul
seal should be provided but in molding a rectan
gular sheet, rather thin and having a length, say, 60 taneous release of the contained vapors and gases
to cause substantially complete resini?cation of a
several ‘times its width, it is ordinarily sufficient
constituent part of the ligneous cellulose ?bers.
to seal only the long. edges. The requirement
5. A process of molding a material comprising
is that the seal be sufficient that under the con
lignins and cellulose in a mold which comprises
ditions of molding the escape of expanded steam
and gases be restricted su?iciently to build up 65 the Steps; Substantially sealing the mold against
the escape therefrom of gases and vapors formed
the required internal pressure to bring about the
from the material, subjecting the material to heat
desired reactions. '
and pressure, relieving the pressure slowly allow
It has been found that the reactions occurring
ing the escape of entrapped vapors and gases, and
during the described molding operation may be
pressure.
\
>
_
more or less assisted or hastened‘ by the use of’ 70 fully relieving the molding pressure to cause sub
stantially complete resini?cation within the ma
certain catalysts as in connection with molding
with the conventional synthetic resins. Because
6. The process of molding from moist ligneous
of this, in some instances it may be advisable to
' add, before compression, to the mass to becom
cellulose substance having a moisture content of
pressed a small amount of a catalyst, say, a frac- 75 about 9%. a hard dense product which com
terial.
‘
‘
2,402,554
11
12
prises the steps: compressing the ligneous cel
lulose substance with simultaneous application
tung oil, charging the treated ligno-cellulose sub
of heat at a temperature of about 240 degrees
to 325 degrees F. to cause the substance to be
compacted and thoroughly heated and a high in
reducing the volume of the mold to cause an
external pressure to be exerted on the charged
substance of between 500 and 1500 pounds per
ternal pressure to be built up within the mass
01' the substance being compressed through con
version of the moisture contained therein into ,
stance into a mold of variable internal volume,
square inch, concurrently sublecting the com
pressed substance to a temperature of between
240 and 440 degrees Fahrenheit causing an in
ternal pressure to be formed within the com
steam and expansion of the steam and contained
gases, restraining the free escape of the expanded 10 pressed ‘mass, maintaining the aforesaid condi
steam and gases from the substance being com
tions for a period of about ten (10) minutes.
pressed, slowly lowering the compression pressure
' maintaining the internal pressure within the com
to cause the excess internal pressure to be relieved,
pressed mass during such period of treatment,
and recompressing the substance during a short
slowly releasing the internal pressure, and main
period to- cause a hard and dense product to 15 taining the external pressure and heating for a
be formed.
period of several minutes after the release of the 7. A molded product comprising ligneous cellu
internal pressure.
lose ?bers originally characterized by a benzol ex
13. The method of producing a hard. dense, co
traction of substantially 1.9% solubles, the ?bers
herent and homogeneous resini?ed product which
adhered and bound together by reaction products 20 comprises the steps: charging a molding charge
01' the such ligneous cellulose ?bers reacted in
comprising divided ligno-cellulose, and a catalyst
situ, whereby the molded product is characterized
into a mold of variable internal volume, reducing
by a benzol extraction of substantially 3.3%
the volume of the mold to cause an external pres
solubles.
sure to be exerted on the charged substance of
8. A hard, dense and homogeneous molded 25 between 500 and 1500 pounds per square inch,
product comprising resinous reaction products of
concurrently subjecting the compressed substance
ligneous cellulose ?ber characterized by a benzol
to a temperature of between 240 and 440 degrees
extraction of substantially 3.3% solubles having
Fahrenheit causing an internal pressure to be
throughout the body thereof an interspersed re
formed within the compressed mass, maintaining
inforcement comprising the unreacted remainder 30 the aforesaid conditions for a period of about ten
of the such ligneous cellulose ?ber.
(10) ‘minutes, maintaining the internal pressure
9. The resinous product produced by subjecting
within the compressed mass during such period
a mass of moist bagasse ?ber simultaneously to
of treatment, releasing the internal pressure, and
elevated temperature and high pressure while re
maintaining the external pressure and heating
strained to prevent the escape of gases and vapors 35 for a period of several minutes after the release
from such mass during its subjection to the ele
of the internal pressure.
vated temperature and high pressure.
14. The method of producing a hard, dense, c0
10. The process of molding, from moist ligneous
herent and homogeneous reslni?ed product which
cellulose substance having a moisturecontent of
comprises the steps: charging a ligno~cellulose
about 9%. a hard and dense product which com 40 substance in ?nely divided form and a catalyst
prises the steps: compressing the ligneous cellu
comprising material selected from the group of
lose substance with simultaneous application of
catalysts comprising hexamethylene tetramine,
heat, the creation of a high internal pressure
analine hydrochloride, acid catalysts, alkali cata
built up within the mass of the substance being
lysts, alkali hydroxide catalysts, and carbonate
compressed through conversion of the moisture
catalysts, into a-mold of variable internal volume,
contained therein into steam and expansion of
reducing the volume of the mold to cause an ex
.the steam and contained gases, and providing a
ternal pressure to be exerted on the charged sub
seal restraining the free escape of the expanded
stance of between 500 and 1500 pounds per square
steam and gases from the substance being com
inch, concurrently subjecting the compressed sub
pressed.
'
60 stance to a temperature of between 240 and Y440
11. The method of producing a hard, dense, co
degrees Fahrenheit causing an internal pressure
herent and homogeneous resini?ed product which
to be formed within the compressed mass, main
comprises the steps: charging a ligno-cellulose
taining the aforesaid conditions for a period of
substance in ?nely sub-divided form into a mold
about ten (10) minutes, maintaining the internal
of variable internal volume, reducing the volume 55 pressure within the compressed mass during such
of the mold to cause an external pressure to be
period of treatment, releasing the internal pres
exerted on the charged substance of between 500
sure, and maintaining the external pressure and _,
and 1500 pounds per square inch, concurrently
heating for a period of several minutes after the
subjecting the compressed substance to a tem
release of the internal pressure.
perature of between 240 and 440 degrees Fahren 60
15. A process for producing substantially ?ber
heit causing an internal pressure to be formed
less homogeneous masses from woody material,
within the compressed mass, maintaining the
consisting in steaming the woody material in a
aforesaid conditions for a period of about ten
pressure-tight vessel at a temperature above
(10) minutes, maintaining the internal pressure
150° C. and under a mechanical pressure of at
within the compressed mass during such period of 65 least 100 atmospheres, until a practically ?berless
treatment, slowly releasing the internal pressure,
and maintaining the external pressure and heat
homogeneous material is obtained, and molding
said material by the action of heat and mechani
ing for a period of several minutes after the re
cally exerted pressure in the presence 01’ saturated
lease of the internal pressure.
steam in the same pressure-tight vessel to form
12. The method of producing a hard, dense, co 70 molded solid masses of low water and ash content.
herent and homogeneous resini?ed product which
16. The process of molding a body which com
comprises the steps: treating a ligno-cellulose
prises the steps: heating and compressing the
substance in ?nely divided form with a water
body, a narrow width of the body at and around
~ proo?ng selected from the group of usual paper
the perimeter thereof being ?rst compressed to
waterproo?ng substance-rosin, para?ine, and 75 prevent the escape of gases from the interior por
2,402,554
13
tion of the body to the exterior, the compression
of that portion of the body interiorly of said
.
14
edge of the body against the escape of gases and
vapor therethrough and causing an internal gas
and vapor pressure to build up within thev body
compressed narrow width of the body at and
and to be maintained during the compression
around the perimeter thereof while continuing
and increasing the compression of the said nar 5 thereof.
'
FERGUS A. IRVINE;
row width of the body at and about the perimeter
EMILE FREDERICK, J‘R.
thereof, and therebysecurely sealing the outer