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Патент USA US3090116

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May 21, 1963
Filed June 26, 1959
,4770 /YEYS
Patented May 2l, 1963
natural rubber rollers are durable, heat and moisture
resistant, and 'are capable of handling a larger variety of
inks than are composition rollers, their printing quality
does not compare with that of the composition rollers.
For these gains, however, the rubbers and synthetic rub
sota Mining & Manufacturing Company, St. Paul,
'nn. a cor eration of De aware
bers sacrifice good surface tack or “thumb appeal” and
Ml ’ rin-,aprirne 26, 1959, ser. No. 823,033
printing quality. Further, with the exception of the
4 Claims. (Cl. 29-132)
polyurethane rubbers, they cannot be cast in molds and
necessitate slow, laborious hand labor in their formation.
This invention relates to printing or inking'rollers used
to accept ink from a supply fountain or the like and con 10 The various types of rollers are compared and contrasted
in the American Pressman, January and February 1959
vey and transfer this ink to a printing plate.
issues, parts 1 and 2 of the article entitled, “Printing
More particularly this invention relates to a roller
Rollers” by James K. Brown.
having an inking surface layer of a cast rubbery organic
The rollers of this invention can, like composition and
polymer which prints With the quality of. composition, 15 polyurethane
synthetic rubber rollers, be cast in molds
eg., glue and glycerine type, rollers While possessing
and provide printing quality which appears to match that
durability, environmental insensitivity, dimensional sta
of composition rollers coupled with durability and other
bility and ability to handle inks more closely akin to
characteristics closely akin to those of synthetic rubber
synthetic rubber rollers, e.g., Neoprene, yarid B_una rubbers
including the polyurethane syntlietics.
and the like. While the invention has particular refer
These new printing rollers have a tackiness or surface
ence to ink form rollers, namely those inking rollers 20
feel of the type usually associated with composition
which contact the printing surface of a printing plate, the
and at least the surface layer thereof comprising
invention is not limited to inking rollers in the‘form
a rubbery organic polymer of a carboxyl terminated
position but applies to any roller in lghe train of inking
polyester of a polyol and a polycarboxylic acid, which
rollers, (including “speck” or “hickey” scavenging
25 polyester is modified with and cured by the addition
rollers), used on a printing press to control the transfer
thereto of a N,N’-bis-l,2-alkylene amide of a dicar
of ink from a supply fountain to a printing plate on a
boxylic acid. The N,N’-bisamide and the polyester are
combined so that there is at least one amide group for
Rollers are conventionally formed of an axial shaft
reactive carboxylic group of the polyester, and to
having an intermediate cylindrical enlargement on which 30 each
this end about 30% more than the stoichiometric equiva
a rubbery inking surface layer is provided by casting,
Albert E. Raymond, St. Paul, Minn., assignor to Minne
lent amount of amide required to react with the free
or Wrapping and then vulcanizing. ÍI'he ends of the shaft
carboxyl groups is normally utilized in the reaction mix
serve as journals for rotation in printing press bearings.
There are numerous variations to this construction.
Thus, it has been known to ñrst cover the cylindrical en
largement With a sponge or soft rubbery layer and there
The polyester may be formed from any convenient
35 combination of branched chain or ether oxygen contain
after apply to it or some subsequent layer a surfacing
layer of ink transferring rubber or the like. Another
procedure, which has recently been introduced, is‘that
ing alkylene diols and dicarboxylic acids compatible with
N,N’-bis-l,2-alkylene amide to provide a pourable or
castable system capable of curing to solid rubbery organic
polymers useful as printing roller surfacings.
of providing a vacuum contractible rubber body, of either 40
Useful polyesters have been found to be those formed
natural or synthetic rubber, on the roller enlargement and
from branched or ether oxygen containing alkylene diols
over this body slipping a removable sleeve which sleeve
containing between 3 and about 8 carbon atoms, such as
is provided with a surfacing layer of the particular com
1,2-propylene glycol, 1,3-butylene glycol, neopentyl Vgly
position to be used as the ink transfer composition..
col, diethylene glycol, triethylene glycol, tetraethylene
Regardless of how the surfacing layer is to be applied,
whether as the integral body of the roller or as a surfac 45
glycol, dipropylene glycol, tripropylene glycol, and the
nearly combine the desirable properties of composition
tional iriolecules being exempliiied by glycerol, trimeth
like, and alkylene dicarboxylic acids wherein the alkylene
ing layer on a removable sleeve fitting over the _roller
group is from 2 to about 110 carbon atoms in total, as for
body, or otherwise, this invention pertains to printing or
example, succinic, adipic, diglycolic, azelaic, sebacic, and
inking rollers having at least as the surfacing layer there
isosebacic acids. These compounds are combined to pro
of a rubbery organic polymer of a carboxyl terminated
organic polyester cured with an N,N’-bis-1,2-alkylene 50 vide polyesters having acid numbers (calculated by end
group determination) from about 30 to 60.
amide of a dicarboxylic acid. Such polyesters are dis
In addition, a minor amount of a polyfunctional ma
closed in application Serial No. 668,038, ñled June 26,
terial having more than two reactive hydrogens, usually
1958, by Watkins et al., now abandoned, and the poly
mers and method of their formation described therein is
in the form of reactive OH or COOH groups, is included
incorporated hereinto by reference.
in the alkylene diol and dibasic acid mixture to provide
Rollers surfaced with these new inking surfacings more
crosslinking sites on the polyester chain, such polyfunc
and synthetic rubber rollers than has heretofore been
ylol propane, trimesic acid, citric acid, tricarboxylic acid,
possible. While composition rollers are inexpensive,
and the like. Of course the functionality may be greater
capable of formation by casting in molds, possess excel
than trifunctionality as provided by compounds such as
lent surface tackiness and are known to provide printing
pentaerythritol or benzene tetracarboxylic acid. The
of the highest quality, their short press lives, low di
amount of such material to be added is calculated to
mensional stability, and inability to withstand moisture
provide an average of from about 1li to about l branch
and heat restrict their use to low speed letterpress print
ing presses. On the other hand while synthetic and 65 of such material per polyester molecule.
The N,N'-bis-l,2-alkylene amides to be used are those
corresponding to the general formula:
abandoned, supra, the roller body containing circumfer
entially spaced longitudinal passages 26 into which the
rubbery body 24 of the roller contracts upon the appli
cation of 4a vacuum to the passages thereby reducing the
diameter of the roller body.
Over lthis roller body is
mounted a removable sleeve 28 of a nonstretchable tubu
lar core 30‘ having an inside diameter in-termediate the
reduced and normal 4diameters of the rubbery body 24
wherein R represents a member of the group consisting of
and surfaced with a rubbery polymer 32 of a bisamide
alkylene radicals having from 4 to 18 carbon atoms and
cured polyester.
single ring arylene radicals such as the 1,3-phenylene and 10
The formative steps of making the rollers and evaluat
1,4-phenylene radicals and R1 and R2 represent a mem
ing »their performance are given in the specific examples
ber of the group consisting of hydrogen and lower alkyl
which follow, which examples it is to be understood are
radicals, from l to about 3 carbon atoms in length.
for purposes of illustration only and not determinative of
Fillers, extenders, pigments, catalysts and modiñers may 15 the scope of the invention.
be added to the castable composition as desired yto stiften,
reinforce, increase abrasion resistance and tensile strength
or otherwise “tailor” the properties of the solid rubber
Printing rollers were produced from the following liquid
polymers as required.
Also, antioxidants . to stabilize
against aging can be added to enhance the utility of the 20
polymers as printing roller surfacing layers.
Printing rollers exhibiting excellent printing charac
teristics have been made from trimethylol propane modi
fied lglycol-acid polyesters cross-linked with N,N'-bisethylene isosebacamide.
These rollers possess a char
acteristic ‘ïtacky” feel approximating that of glue-glycerine
type rollers and believed responsible for their superior
Diethylene glycol ________________________ __
Adipic acid _____________________________ __
Trimethylol propane _____________________ __ 0.0391
The glycol, acid and trimethylol propane were mixed to
gether and air driven out by bubbling ni-trogen there
Thereafter a vacuum was applied to a kettle
containing the mixture at -a temperature of about 200° C.
for several hours to provide :an acid terminated polyester,
with adequate toughness, heat and abrasion resistance, di
mensional stability, elastic recovery and solvent .resistance 30 having a theoretical acid number of about 50.7, with an
lactual acid number in the range `of 50' to 55. The polymer
for high speed, long time printing use on high speed litho
displayed an average degree 'of polymerization of 25.2
and letterpress printing presses, the latter use being more
units/mol (each unit being calculated las one half of the
demanding than similar utility as inking rollers on the
printing quality.
These new rollers combine this feel
total molecular weight of the repeating unit formed by the
These 35 reaction of one ethylene glycol molecule with one acid
molecule in the polyester chain.) The amount of tri
rollers have also been found to be useful in the held of
rnethylol propane added »was calculated to provide ap
prin-ting with glycol-based inks (such as used in the food
proximately one half of a trimethylol propane branch
!Wrapper printing), which inks decompose glue-glycerine
on the polymer chain for each polyester molecule, these
and polyurethane rollers. Fur-ther, these new surfacings
lithopress, e.g., planographic printing, usually from rotary
offset presses printing from lithographic plates.
are heat resistant to temperatures `in the order of 320° F., 40 branches serving as crosslinking or branching sites in the
indicating their utility in very high speed printing opera
further formation of the polymer. The -branching calcu
lation is within the gelation equation system of P. S. Flory
in his “Principles of Polymer Chemistry,” Cornell Press,
In the accompanying drawing there is illustrated in
Ithica, N.Y., 1953, pages 347 to 397.
FIGURE l -a diagrammatic view of a rotary oifset litho
To 6 par-ts by weight of the polyester thus formed was
graphic printing press; in FIGURE 2 there is illus
added one part by Weight of N,N’-bis~ethylene isosebacarn
trated a roller made in accordance with the teachings of
ide. The resulting liquid mass was poured into the open
this invention; and, in FIGURE 3, there is illustrated a
top of an upstanding cylindrical mold, the inside `of which
vacuum contractible roller having a removable sleeve
had been coated with ra silicone release composition.
mounted thereon, which sleeve has an inking surface
layer thereon formed in accordance with lthe teachings of 50 Concentrically disposed within the mold was a roller shaft
with the ends thereof projecting through the ends of the
this invention.
mold so that 4only the cylindrical enlargement of the shaft
Referring first specifically -to FIGURE l there is dis
was disposed in the mold, spaced from the wall of the
closed therein schematically a typical rotary offset press
mold about ’1/2 of an inch (radially). The liquid mix
construction designated in its entirety by the numeral 10.
ture was poured into the mold «to fill the same. After
It is -to be understood that this is illustrative only of one
filling, the mold twas placed in an oven -at 250° F. for
general type of printing press in which `the rollers of this
about 2 hours to cure the bisamide containing polyester.
invention have particular utility. Basically, insofar as
The roller, when removed from the mold had a clear, al
roller use is involved, this -type of press distinguishes from
most water white surfacing 'layer thereon of solid rubbery
Ia letterpress in that in a letterpress the ink form ìrollers
contact a relief image printing plate having raised inking 60 bisarnide cured polyester. The roller displayed a durom
eter, Shore durometer A2 scale, of about 35, and by
surfaces Whereas in an olfset press, the form rollers con
virtue of the longitudinal passages therethrough, was
tact smoother surfaced planographic plates. The roller
vacuum contractible in the manner described in copeud
trains 14 and 12 are exemplary of ink supplying `and ink
ing application Serial No. 694,549, supra.
repellant supplying sys-tems. The ink form roller posi
tions are those contacting the plate cylinder and the 65
ink form rollers are designated by the numeral l16.
Inking roller sleeves, for mounting on contractible
In FIGURE 2 of »the drawing Ithe conventional roller
roller bodies made in accordance with the procedures of
application Serial No. 694,549, supra, were made by
having a cylindrical enlargement `2G intermediate the
ends thereof is provided with a rubbery body of a bis 70 mounting a paper sleeve core on a metal mandrel and
placing the same in a closed mold 'of the type noted
amide cured polyester as hereinbefore described desig
hereinabove with respect to the roller formation, the
nated by the numeral 22.
construction is shown wherein -an elongated shaft 1S
In FIGURE 3, there is disclosed a vacuum contractible
roller body 24 formed in accordance with the procedure
outlined in copending application Serial No. 694,549, now
sleeve core being radially spaced concentrically inwardly
about 1A inch from the inner wall surface of the cylin
drical mold.
The mold space was evacuated and Ithe
bisamide containing liquid polyester mixture was drawn
set lithographie press rollers having been surfaced with
these sleeves. The sleeve surface layer durometers varied
into the mold space; the iilled mold was then placed in
an oven at about 250° for two hours to cure the sleeve.
from about 10 to 35 on the Shore A2 scale.
Following the procedure just outlined a number of
sleeves were prepared for various sized -rollers utilizing
various bisamide cured products of the polyester formula
tions listed hereinbelow:
To test the printing quality of the sleeves against the
printing quality of commercially used glue-glycerine, or
composition type, rollers, reflection densitometer readings
Polyester Formulations
were taken on copy printed with the sleeves surfaced with
10 the tive compositions noted in the previous example on
copy printed with a glue-glycerine roller, on a Miller
D-iethylene glycol _________________________ __ .848
Adipie acid ______________________________ __
Trimethylol propane _______________________ __ .0391
Simplex 20" x 26" letterpress, the ynumerical designation
referring to the maximum sheet size that can be used in
the press. Test conditions for all yof the sleeves were
identical and the tests were carried out by placing the
Acid No. between 50-55; average .degree of polym
erization 25.5 units/mol.
surfacings to be tested in the ink form roll position on
Mixture of 117.6 pts. by wt. diethylene glycol and
102.6 pts. by wt. neopentyl glycol __________ __
the press, there being two form rollers.
Five sets of the nonstretchable sleeves surfaced with
Azelaic acid _____________________________ __
Trimethylol propane _____________________ __ 0.0458
the ñve compositions noted in the previous example were
Acid No., 38-40; degree of polymerization, 48.6
and the printing quality compared with glue-glycerine
units/ mol.
Neopentyl glycol __________________________ __
Isosebacic acid ___________________________ __
Trimethylol propane ______________________ -_ .0485
mounted on vacuum contractible form rollers on the press
Each set of rollers was run for 15,000 impressions.
As each set of rollers was changedl new packing and
makeready were applied to the press so that the conditions
of the tests would be as identical as possible.
All of the tests were carried out with a form sheet oom
Acid No. between about 53-58; degree of polymer
posed of 85 and 133 line screens with tones of 910%,
ization 27.3 units/mol.
80%, 70%, 60%, 25% and 10% as well as solid cuts,
Sleeve surfacing layers were formed by mixing each
one running parallel to the printing cylinder and the other
of the polyesters and mixtures thereof with N,N’-bis- 30 perpendicular to the printing cylinder. All printing plates
ethylene isosebacamide, the latter compound being added
were 11 point copper electrotypes mounted on a honey
comb base. The ink utilized in all of the tests was a
in a 30% excess of the stoichiometric amount necessary
to react with all the free carboxyl groups yof the poly
consolidated quick set halftone black and the densitometer
ester in crosslinking the polyester, and curing the resultant
readings taken on 60# coated enamel paper printed with
mixtures to rubbery solids. The following formulations 35 this ink. Ink fountain settings on the press were constant
were utilized in the sleeve surfacing layer construction:
for all sleeves and rollers tested.
Reflection densitometer readings were taken with a
Bz'samìde Cured Polyester Fannulations
densitometer, which comprises a light meter in a light box
with a iilter over the light opening. The particular filter
Pts. by wt.
Polyester B _______________________________ __
Polyester A _______________________________ __
N,N’-bis-ethylene isosebacamide (20 durometer)__ 175
40 to be used is chosen by Iobtaining a zero reading on the
light reilectance scale of the meter on a solid color printed
on the paper and a reading of 100 on the scale on the
unprinted portions of the paper. Consequently, the
Polyester A _______________________________ __ 1300 45
N,N'-bis-ethylene isosebacamide (35 durometer) __
Polyester B _______________________________ __ 1300
N,N’-bis-ethylene isosebacamide _____________ __ 156
Aging stabilizer of a fatty acid amide (“Versamide
uct of a polyamine and a fatty acid (15 du
colored, etc., causing higher readings. In general when
erally referred to in the artt as a halftone, be it a 10%
Polyester B _______________________________ __
7 84
Polyester C _______________________________ __
N,N’-bis-ethylene -isosebacamide _____________ __
“Versamide 140” (20 durometer) ____ _______'___
A completely black surface is a 100% tone surface and
will produce a reading of zero and 4the halftone, i.e., any
thing less than a solid cut; eg., a 90% tone is one wherein
90% of the area is colored and 10% -is uncolored, an
80% is where 80% of the area is colored and 20% un
comparing sleeve and roller readings, a lower reading
signiiies superiority Áon solid cuts and a higher reading
superiority on halftones.
Anything less than a 100% tone, or solid cut, is gen
14‘0,” marketed by General Mills) reaction prod
rorneter) _______________________________ __
smaller the number the darker the printing.
or 90% colored area. The toning is achieved by do-ts
produced by light exposure through a screen on a negative,
which negative is in turn reproduced on the plate and the
plate subsequently etched. The íidelity of the printing
60 color is determined by the number of dots per inch; for
example 133 dots per linear linch being used for high
Polyester C _______________________________ __ 1200
N,N'-bis-ethylene isosebacamide _____________ __ 216
“Versarnide 140” (15 durometer) ____________ __
24 65
The sleeve cores were stiff, tubular, nonelastic members
made up of 3 layers of spirally wrapped, elastomer irn
pregnated paper, the center spiral layers being spirally
iideli-ty, halftone printing on iine stocks and 85 dots per
linear inch being used for coarser stock such as news
In the tables which follow it is to be understood that
in the halftone -areas, the higher numbers, which desig
nated the lighter reading on the scale of the densitome
ter, are the more «desirable whereas on the solid areas
of the scale the lower readings indicate the better quality.
opposite direct-ion to the inner spiral layer of the core. 70 The lengthwise extending solid area represents a longi
tudinal stripe on the printed sheet from the leading, or
A moisture and hydrocarbon solvent resistant permanent
gripper edge of the paper to the trailing edge. Character
adhesive laminated the spiral wraps to one another in
this stripe darkens from the gripper to the trail
the formation of the sleeve core.
wound in the same direction «as the outer layer and in an
ing edge; however, uniformity of color is the effect strived
Sleeves of this nature have been made for and used on
diiîerent printing presses, both letterpress and rotary off 75 for.
Percent herlftone` and No, line screen
rollers under îhe test 'conditions u’filized.l In vfact, some 6 5
of the sleeves out-performed the glue `glycerin@ in »print
Solid area
the tack was lost, however, there was no tendency of the
with cotton cloths and weighed immediately and checked
roller sleeve to glaze and printing quality remained ex
for volume increase. The results are shown in the table
3. 2
7. 4
-0. 005
4. 7
-0. 02
-0. 05
0. 67
1. 9
--0. 02
_0. 08
1. 0
0. 96
5. 5
13. 2
7. 7
19. 4
1. 4
0. 1
6. 8
16. 4
1. 5
0. 2
22. 9
1. 7
0. 5
10. 5
22. 6
1. 9
0. 6
31. 8
N0Tn.--A:Raw linseed oil ; B=Light mineral oil ; C: Kerosene ; D: Mineral spirit; E=Varnish makers’
and painters’ naphtha; FzTap water.
Compression set tests, carried out by compressing sam
Thus, the rubbery polymers of this invention, when
used on the most difficult inking positions on both letter
and maintaining the compression force for 48 hours at 25 press and lithopress printing presses performed well to
provide excellent printing copy while maintaining their
about 72° F., revealed that after release of the com
dimensional stability and durability, thereby combining
pressing force, the average compression set for the sam
composition roller printing quality with the synthetic rub
ples was less than 5%.
ber durability.
As will be noted from the solvent resistance data, these
rubbery polymers are quite easily modified to fit any 30 What I claim is as follows:
ples of polyesters 1-5, 60% form their original height
particular ink base. Thus, where rubbery polymer No.
l. A printing roller having ends thereon for journaling
in bearings of a printing press, a resilient cylindrical roller
5, for example, is not suitable in naphthas and mineral
body intermediate said roller ends, said roller body having
spirits because of the weight increase and volume swell,
at least as the surfacing layer thereof for transferring
polymer No. 2 is excellent in this regard.
Significantly, all of these rubbery polymers are suit 35 printing ink from a supply source to a printing plate a
solid tacky surfaced rubbery polyester cured -with a N,N’able for use with ethylene glycol based inks. ¿Polyure
bis-1,2-alkylene amide of a dicarboxylic acid, said poly
thane rollers, the only other cast rubbery rollers utilized
ester comprising the polymeric reaction product of an
in the printing trade, which rollers generally appear to
alkylene diol containing between about 3 and about 8
comprise polyesters of diethylene glycol and adipic acid
cured with mixed isomers of toluene diisocyanate and 40 carbon atoms in the alkylene group, an alkylene dicarbox
ylic acid containing from about 2 to about l0 carbon
plasticized with a phosphate ester cannot be used with
atoms in the alkylene group, and a minor amount of a
glycol based inks as the glycol base decomposes the
polyfunctional organic compound having more than two
polymer. Also significant, from another point of view,
the N,N’-bisamide cured polyester rubbers forming the
reactive hydrogens.
inking surface layers of this invention contain no plasti 45 2. A printing roller having ends thereon for journaling
in bearings of a printing press, a resilient cylindrical roller
cizers, which sometimes tend to migrate and flow under
body having at least as the surfacing layer thereof for
conditions of use and surface grinding.
transferring printing ink from a supply source to a print
ing plate a solid tacky surfaced rubbery polyester cured
N,N’-bisamide cured polyester rubbery polymer sur 50 with a N,N’-bis-l,2-alkylene amide of a dicarboxylic acid,
faced sleeves have been run in the ink form roll positions
said polyester comprising the polymeric reaction product
on ‘both letter-press printing presses and offset lithopress
of an alkylene diol containing between about 3 and about
printing presses under prin-t shop conditions and have per
8 carbon atoms in the alkylene group, an alkylene di
formed satisfactorily.
carboxylic acid containing from about 2 to about l0 car
Sleeves surfaced with polymer No. 2 of Example l 55 bon atoms in the alkylene group, and a minor amount of
mounted on vacuum contractible rollers in the ink form
a polyfunctional organic compound having more than two
roll positions on a Davidson model 241 ten «inch litho
reactive hydrogens, said N,N’-bisamide having from l to
press, a small rotary offset press, produced consistently
5 carbon atoms in each of said 1,2-alkylene groups, and
high quality printing copy over long periods of time with
said dicarboxylic acid forming said amide being selected
out loss of roundness or dimensional stability, remaining 60 from the group consisting of alkylene dicarboxylic acids
unaffected by temperature and humidity changes, chang
containing from 4 to 18 carbon a-toms inthe alkylene radi
ing ink bases, or ordinary cleaning solvents used to wipe
cals and single ring arylene dicarboxylic acids.
3. A printing roller having ends thereon for journaling
the surfaces clean.
Similar sleeves surfaced with polymer No. l of Exam
in bearings of a printing press, a resilient cylindrical body
ple l on the ink form roll positions of a Miehle 29 letter 65 intermediate said ends comprising an ink conveying and
press, a small flatbed press, produced consistently high
transferring layer for conveying ink from a supply source
quality printed copy for millions of impressions with no
to a printing plate, said layer having a soft, tacky feeling
special care in cleaning or handling and without glazing
surface and comprising a solid rubbery, nonporous
or hardening of any kind. Further, these sleeve surfac
branched chain carboxyl terminated polyester cured with
ings could and were ground down on a commercial grind 70 a N,N’~bis-l,2-alkylene amide, said carboxyl terminated
ing machine to provide clean printing surfaces without
polyester having an acid number of between about 30
diñiculty or deterioration. The newly exposed surfaces
and 60 and comprising the reaction product of a branched
possessed the same characteristic tacky feel as the original
chain -glycol of from 3 to about 8 carbon atoms, an alkyl
surfaces and printed with the same high quality. This
ene dicarboxylic acid wherein the alkylene group contains
tacky feel appeared to last approximately twice as long 75
as the tacky feel lasts on a glue-glycerine roller. When
from about 2 to about 10 carbon ato-ms, and a minor
amount of a hydrocarbon polyol containing at least three
reactive hydroxyl groups, said bisamide being the amide
of a dicarboxylic acid selected from the group consisting
of alkylene dicarboxylic acids wherein the alkylene radi-
References Cited in the file of this patent
F1013’ ---------------- -- Apr» 22, 1952
cal contains from 4 to 18 carbon atoms in the alkylene 5
Melamed ------------ -- NOV- 16, 1954
Great Britain _________ __ May 30, 19576
radical, and single ring arylene dicarboxylic acids.
4. The roller of claim 3 wherein said surfacing layer
is on a removable sleeve.
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