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Патент USA US2406718

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Patented Aug. 27, 1946
. , Raymond E. Thomas, Newburgh, N. Y., assignor to4
E. Ldu Pont Vde Nemours & Company, Wil
g _ n,mingtom Del., a corporation of lDelaware
' ' Application July 31, 1943„Serial No. 496,947
4 Claims.
(Cl. 101-407)
This invention ¿relates »to the embossing of
Vsheet materialïandïmore particularly to increas
tion of the engravedroll. The deterioration is
manifested by a crumbling and f‘dusting-off” of
the outer surface of the paper> bowl and, in time,
by the spalling _of larger pieces which render the
ing the vlongevity of paper coun-ter rollers, known
asbowls, in the roller embossing operation of
' sheet'material.
Inv producing surface pattern leffects on sheet '
bowl unfit for use.
This invention has for anl object a method for
material by means yof embossing, two methods
are commonly used; namely, platel embossing and
treating paper embossing bowls to render them
more resistant topowdering or'fiaking of the
roller «eml'aossingv Y In the »plate embossing meth
paper surface upon continued operation. YAri
ïod the’s'heet material is' pressed between a metal 1.0 other object is to lengthen the useful lifeof paper
plate bearing theï'desired design in Vrelief and a
embossing bowls beyond their ynormally expected
operating period. Other objects will appear
softer fibrous base which has the »counter of the
design onthe metal‘piate. '
. 4
4hereinafter as the description of theV invention »
' In the roller 'embossing method engraved metal
-rolls are used 'in_coniunction with softer counter n
"rolls or bowls, which‘areusually m'adeof paper.
Y proceeds.
In the normal operation of >a roller, embossing
rmachine the customary method for using a new
The îpaper bowls are "made by Yplacing paper discs
paper bowl is to wet the bowl with water and to
or washers at right -an'g‘les’to'the axis of a metal
’mandril and then‘forcing 'the paperV discs into
intimate contact yby means of pressure, after
which .the discs are secured in position by use of
rigid metal end supports connected to ¿the man
~dril. The'paper vbowl carries a 'pattern counter
bring the metal embossing roller in contact with
the bowl, 4first'under low pressure and then with
gradually increasing pressure until full operating
pressure is attained. This method o_f “cutting
to Íthe pattern on thelmetal roll.
' '
in” a design allows a clear, well defined counter
impression of the' engraved roll to be reproduced
on the bowl. The machine then’may be used to
In producing an embossed pattern by the rollerA
25 emboss sheet material for a considerable period
' embossing `method onÍs'h’eét material, it isv passed
of time without giving any trouble with the bowl
under ordinary operating conditions. Occasion
*between the'metalroller'andíthe' paper bowl using
'suiiicient :pressure ' and -heat'to secure the desired
The heat is íapplied 'customarily by ‘heating -the
metal'roll althoughiitiisîsometime's advantageous
j-to fpreheat the material vbefore it contacts the
A»rollers ‘and vuse Ya cool metal roll, to secure the
. desired pattern. For y“deeper patterns more heat
_ ally the engraved roller andthe bowl may get out
of register and give embossed designs which are
30 not clear cut and distinct. This is corrected by
Y’ wetting the bowl with water, thereby swelling the
paper übers and obliterating the previous design.
‘The original process of “cutting-in” the design
may then be repeated.
or-'lpressure-usually areappliedíthan 'for shallower
designs: For -pyroxylin ’coated fabrics, Vpressures '»
After embossing a considerable quantity of
sheet material in a roller embossing machine, the
of 35 -to '50 Vtonsfat `they area of contact of the
bowl begins to show signs of deterioration caused
r.metal-and’paperrolls, and *temperatures of 200°
by the pressure, heat and abrading action of the
F. to 300° vF'. are used. 'Coated‘fabri'cs utilizing
operation. This deterioration manifests itself in
:synthetic resins'of a >more 'thermoplastic nature 40 a hardening, crumblingor “dusting-off” of the
fare sometimes embossed >at ’pressures as high as. »
surface of the bowl. At first the dust is a poten
80 tons and temperatures as lowas 60° F. The
tial source of damage to the material merely be
K .metal roll is -driven by» a series of gears, chains,
cause of the dirt contamination involved, but
orother'mechanical means, while the >paper bowl
soon the 4deterioration progresses to such an ex
- may be turned 4either by 'the friction against the 4.5 tent that a satisfactory grained material cannot
be ysecured because of the poorly defined counter
¿.Jnetalfroll and the sheet material or by a seriesï»
of gears, chains; vor other mechanical meansV act
impression of the bowl. In certain cases where
ing in conjunction with the means used to drive
an embossing cylinder of a smaller size is avail
the metal roll.
able the bowl may be “turned down” on a lathe
In ,the embossing-of sheet material, such as a 50 in the yconventional manner. In most cases the
„coatedfabrid the pressure and heat of the opera- î' paper is removed to a depth o'f a quarter of an
îtion tend in time ¿to cause such deterioration of
K .the paper bowl as to .render it uselessibecause the
-embossed impressions arenot’ sufûciently clear
A cut and will not Agive aftru-e embossed reproduc
,¿ inch.
The Ysame process is-thenfollowed as with
‘a new ybowl in preparing and using it for emboss
ing. In time the"‘turned down” bowl will deteri
.Orate on the surface and must be discarded unless
ing of material with a deep character, or grain,
was beginning to show "dusting off” of the sur
face. This would normally have resulted in the
replacement or “turning-down” of the bowl. In
this case, however, the bowl was given a liberal
brush coating of the following solution while the
a still smaller sized cylinder is available in which
case the “turning-down” procedure may be re
peated again. Normally at this stage the bowl
must be replaced.
It has been found that the life of a bowl may
be prolonged considerably beyond the stage when
embossing cylinder was operating in contact with
“dusting-01T” has begun by the use of a composi
the bowl under approximately 50 tons pressure
and 270" F. temperature:
tion which prevents the paper fibers of the bowl
surface from crumbling. This is accomplished by
utilizing an aqueous solution of a water soluble 10
polyvinyl alcohol resin, suitably plasticized so as
to prevent embrittlement of the surface. The
water soluble resin may be applied to the sur-»
Bowl preservative composition
nPart A:
face of the manufactured bowl or may be in
corporated into the paper before it is placed 15
on the bowl mandril. A convenient method is
to impregnate the formed paper sheet before it `is
cut into sections; another method is to incor->
porate the resin directly'in the slurry from which
Per cent
Polyvinyl alcohol _________________ __
____ __
Part B-Glycerine ____________________ __ 26.50
Part C`--Water _______________________ __ 29.00
The above composition was prepared by mak
ing a slurry of the polyvinyl alcohol and cold
water of part A. This slurry was then mixed
for use with another cylinder after the bowl
while being heated in a steam jacketed kettle to
first shows signs of failure, the impregnating com
give a lump-free clear dispersion. Part B was
position mentioned above also is of value as it
then added while the mixture was stirred, and
tends to minimize the depth of deterioration.
the water of part'C was added hot with continued
Normally deterioration, embrittlement and-hard
stirring to give the finished composition.
ening will take place to a greater depth than the
When applied to the bowl which was operating
l@ inch removed on the lathe. When the im
in the normal manner in conjunction with the
pregnating solution is used, this deterioration does
not take place to any extent at depths of 1A; inch 30 embossing cylinder as described above, the heat
of the cylinder served to evaporate the water and
or more and in this manner affords a resilient
the sheet of paper is formed.V
In the case in which a bowl is “turned down”
-surfaceon a “turned down” bowl.
give a bowl whose outer surface was saturated
with the polyvinyl alcohol, glycerine mixture.
In the preferred embodiment of the invention
This mixture served to bind the paper ñbers to
a solution of polyvinyl alcohol, dissolved in water
and Vplasticized with glycerine or similar water 35 gether and prevent the crumbling and “dusting
oif” which causes the bowl to become useless.
soluble polyhydric alcohol is applied to the sur
The bowl which was treated as described above
face of the bowl in sufñcient quantity to im
was used in normal operation for more than two
pregnate the surface layers thoroughly. The
months before it was necessary to replace it. This
bowl is thenV subjected to the “cutting-in” process
previouslydescribed. The heat and pressure of 40 added service represents a definite economic
the “cutting-in” process evaporates the water
The primary use of the invention is' to in
and leaves the paper fibers of the bowl impreg
crease the useful life of paper bowls used in
nated with the polyvinyl alcohol-glycerine mix
the roller embossing of sheet material. The in
In the drawing, Figure 1 represents a( diagram 45 vention will also find wide use where paper or
other water absorbent materials are subjected to
matic section of an embossing bowl prepared
repeated or prolonged high pressures and high
~- according to the present invention. Figure 2 is
a diagrammatic section of the bowl of Figure 1
The treatment of roller embossing bowls with
in combination with a conventional embossing
roll bearing a design. In both ñgures the same 50 plasticized polyvinyl alcohol solutions inhibits
deterioration of the surface of the bowl to such
numerals refer to the same parts of which 4 is a
an extent that it may be used far beyond its nor
mandril provided with a flange against which a
mal period of usefulness. Another advantage
large retaining washer I is placed. The paper
is that when applied to new bowls and occasion
discs which have been impregnated with poly
vinyl alcohol or which subsequently may be coated 55 ally during the normal life of the bowl, deteriora
tion will not only be retarded but will also not
with it are threaded onto the mandril. When
take place to as great a depth. 'I‘his latter be
sufficient of the paper discs have been mounted
havior permits the bowl to be more readily “turned
on the mandril another similar washer l is placed
against them and forced together tightly by
down” to a Isamaller size and still have a resilient,
means of nutI 3. After the paper discs have been 60 undeteriorated surface. Other advantages will
be apparent to those Skilled in the art.
suñiciently compressed and treated with a poly
It is apparent that many widely different em
vinyl alcohol solution containing a plasticizer,
bodiments of this invention may be made without
the bowl is run under high pressure at elevated
temperature against the embossing roll to cut in
departing from the spirit and scope thereof, and
a counter design in the peripheries of the com 65 therefore, it is not intended to be limited except
pressed paper discs. Subsequently a fabric 5 may
as indicated in the appended claims.
be embossed by passing it between the bowl and
I claim:
1. An embossing bowl capable of being cut in
the embossing roll as shown in Figure 2. The
by a counter embossing roll to form a clear well
coated fabric is then wound up in a conventional
manner on wind-up roll 6.
70 defined impression and also highly’resistant to
The following description of the preferred em
temperatures up to about 300° F. comprising a
large number of centrally perforated paper discs
bodiment is given as an illustration. This de
scription is not to be construed as limiting the
impregnated at least on their periphery with a
invention to this preferred embodiment.
A bowl which had been used in the ßmbOSS
water soluble polyvinyl alcohol composition, a
75 mandrel passing through the said perforations
and end plates forholding the discs in com
pressed relation.
. 2. The bowl of claiml 1 in which the paper is
impregnated with a composition consisting of
polyvinyl alcohol, glycerine and Water.
I3. The bowl of claim 1 in which the paper is _
impregnated with a composition containing 4
parts of polyvinyl alcohol and 26.5 parts of
4. A method of treating paper embossing bowls 10
which comprises impregnating the paper with an
aqueoussolution of polyvinyl alcohol and a plas
ticizer and thereafter cutting in the surface of
the said bowl by running it in contact under
pressure at an elevated temperature with a coun
ter embossing roll until a clear Well defined coun
ter impression of the embossing roll is repro
duced on the bowl.
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