U.S. patent number RE38,468 [Application Number 09/838,797] was granted by the patent office on 2004-03-23 for replaceable sleeve.
This patent grant is currently assigned to Day International, Inc.. Invention is credited to Thomas Gerald Ferguson, William James Lane, III, Michael Edward McLean.
United States Patent |
RE38,468 |
Lane, III , et al. |
March 23, 2004 |
Replaceable sleeve
Abstract
A replaceable sleeve having a working surface is provided which
is adapted to be mounted on a carrier. The sleeve includes an inner
polymeric layer, a reinforcing layer overlying the inner layer, an
intermediate polymeric layer overlying the reinforcing layer, and
an outer polymeric layer. The sleeve may include a cushion layer
between the intermediate layer and the outer layer. The layers
comprising the sleeve are formed around a support and then cured
simultaneously in a single step. The resulting sleeve may be used
in printing operations or in other applications such as coating,
embossing, laminating, calendering and the like.
Inventors: |
Lane, III; William James (Black
Mountain, NC), McLean; Michael Edward (Waynesville, NC),
Ferguson; Thomas Gerald (Waynesville, NC) |
Assignee: |
Day International, Inc.
(Dayton, OH)
|
Family
ID: |
31980875 |
Appl.
No.: |
09/838,797 |
Filed: |
April 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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758808 |
Dec 4, 1996 |
5860360 |
|
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Reissue of: |
151913 |
Sep 11, 1998 |
05983799 |
Nov 16, 1999 |
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Current U.S.
Class: |
101/375; 101/376;
101/401.1; 492/50; 492/56 |
Current CPC
Class: |
B32B
27/12 (20130101); B41N 6/00 (20130101); B41N
7/00 (20130101); B41N 10/04 (20130101); B41N
2207/02 (20130101); B41N 2207/14 (20130101); B41N
2207/04 (20130101); B41N 2210/02 (20130101); B41N
2210/04 (20130101); B41N 2210/14 (20130101) |
Current International
Class: |
B32B
27/12 (20060101); B41N 7/00 (20060101); B41N
10/00 (20060101); B41N 10/04 (20060101); B41F
027/00 (); B41F 030/00 () |
Field of
Search: |
;101/216,217,218,375,376,401.1 ;428/909
;492/18,48,49,50,51,52,56 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0448469 |
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Sep 1991 |
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EP |
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0520279 |
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Dec 1992 |
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EP |
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0545468 |
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Jun 1993 |
|
EP |
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0715966 |
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Jun 1996 |
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EP |
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0727326 |
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Aug 1996 |
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EP |
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1250912 |
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Oct 1971 |
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GB |
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58114935 |
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Jul 1983 |
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JP |
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58114936 |
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Jul 1983 |
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JP |
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62-124993 |
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Jun 1987 |
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JP |
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WO 91/11330 |
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Aug 1991 |
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WO |
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Primary Examiner: Funk; Stephen R.
Attorney, Agent or Firm: Dinsmore & Shohl LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No.
08/758,808 filed Dec. 4, 1996 now U.S. Pat. No. 5,860,360.
Claims
What is claimed is:
1. A replaceable sleeve adapted to be mounted on a carrier
comprising: a) an inner polymeric layer; b) a reinforcing layer
comprised of fibers, said reinforcing layer overlying said inner
layer and being adhered directly thereto; c) a substantially
void-free intermediate polymeric layer overlying said reinforcing
layer and being adhered directly thereto; and d) an outer polymeric
layer forming a working surface; wherein said inner polymeric layer
has a Shore A hardness which is equal to or greater than the Shore
A hardness of said intermediate and outer polymeric layers.
2. The replaceable sleeve of claim 1 in which each of said layers
has a thickness of from about 0.005 to 0.750 inches.
3. The replaceable sleeve of claim 1 in which said layers have been
cured in a single vulcanizing step.
4. The replaceable sleeve of claim 1 wherein said sleeve is
seamless.
5. The replaceable sleeve of claim 1 in which said inner layer,
said intermediate layer, and said outer layer are comprised of
materials selected from the group consisting of butyl rubber,
nitrile rubber, EPDM rubber, natural rubber, synthetic rubber,
neoprene rubber, blends of nitrile rubber and polyvinyl chloride,
and polyurethane.
6. The replaceable sleeve of claim 1 in which said inner layer
comprises a carboxylated nitrile-butadiene copolymer.
7. The replaceable sleeve of claim 1 in which said inner layer,
said intermediate layer and said outer layer have a Shore A
durometer hardness of from about 20 to 90.
8. The replaceable sleeve of claim 1 in which said inner layer has
a Shore A durometer hardness of at least about 70.
9. The replaceable sleeve of claim 1 in which said reinforcing
layer is comprised of a material selected from the group consisting
of polyester, cotton, fiberglass, cotton-wrapped polyester, rayon,
carbon filaments, and other high modulus synthetic or organic
fibers.
10. A method of making a replaceable sleeve adapted to be mounted
on a carrier comprising the steps of: forming an inner polymeric
layer in a cylindrical shape; mounting said inner layer onto a
support; applying a reinforcing layer comprised of fibers over an
outer surface of said inner layer and adhering said reinforcing
layer directly thereto; applying an intermediate polymeric layer
over an outer surface of said reinforcing layer and adhering said
intermediate polymeric layer directly thereto; applying an outer
polymeric layer directly over an outer surface of said intermediate
polymeric layer; and curing said layers to form said sleeve;
wherein said inner polymeric layer has a Shore A hardness which is
equal to or greater than the Shore A hardness of said intermediate
and outer polymeric layers.
11. The method of claim 10 in which said layers are cured at a
temperature of between about 285.degree. F. to 310.degree. F.
12. The method of claim 10 in which said inner layer, said
intermediate layer, and said outer layer are comprised of a
material selected from the group consisting of butyl rubber,
nitrile rubber, EPDM rubber, natural rubber, synthetic neoprene
rubber, a blend of nitrile rubber and polyvinyl chloride, and
polyurethane.
13. The method of claim 10 in which said inner layer, said
intermediate layer and said outer layer have a Shore A durometer
hardness of from about 20 to 90.
14. The method of claim 10 in which said inner layer has a Shore A
durometer hardness of at least about 70.
15. In combination, a replaceable sleeve and carrier, said sleeve
comprising: a) an inner polymeric layer; b) a reinforcing layer
comprised of fibers, said reinforcing layer overlying said inner
layer and being adhered directly thereto; c) a substantially
void-free intermediate polymeric layer overlying said reinforcing
layer and being adhered directly thereto; and d) an outer polymeric
layer; wherein said inner polymeric layer has a Shore A hardness
which is equal to or greater than the Shore A hardness of said
intermediate and outer polymeric layers, said sleeve being mounted
on said carrier and being readily separable from said carrier.
16. A replaceable sleeve adapted to be mounted on a carrier
comprising: a) an inner polymeric layer comprising a carboxylated
nitrile-butadiene copolymer; b) a reinforcing layer comprised of
fibers, said reinforcing layer overlying said inner layer and being
adhered directly thereto; c) a substantially void-free intermediate
polymeric layer overlying said reinforcing layer and being adhered
directly thereto; and d) an outer polymeric layer forming a working
surface. .Iadd.
17. A replaceable sleeve adapted to be mounted on a carrier
comprising: a) an inner layer; b) a substantially void-free
intermediate polymeric layer overlying said inner layer and being
adhered directly thereto; c) a cushion layer overlying said
intermediate polymeric layer and being adhered directly thereto;
and d) an outer polymeric layer forming a working surface; wherein
said inner layer has a Shore A hardness which is equal to or
greater than the Shore A hardness of said intermediate and outer
polymeric layers. .Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a replaceable sleeve which may be
readily mounted onto a cylindrical carrier, and more particularly,
to a replaceable sleeve comprising a multilayer reinforced
composite which may be cured in a single vulcanizing step.
Rubber-covered cylindrical rollers are widely used in industry for
a number of applications, particularly for web or sheet handling
and processing applications such as the embossing, calendering,
laminating, printing and coating of paper, film, foil, and other
materials. In addition to their use in web processing equipment,
such rubber-covered rollers are often employed in conveyors and
various office machines. Such rollers are typically comprised of a
cylindrical (metal) core or other support with an outer covering of
rubber, elastomer, or polymer material. However, after extended
use, the covering on the rollers wears down and must be resurfaced
or replaced. This typically requires that the rollers be sent to an
outside source where the old surface is ground down and a new
surface is applied. This is inconvenient and expensive as it
requires that the processing equipment be shut down while the
roller is being resurfaced or that the end user stock additional
replacement rollers. Even in the latter instance, the rollers must
be eventually sent out for resurfacing.
Cylindrical rollers are widely used in the printing industry. For
example, printing rollers or sleeves are used in the flexographic
printing industry for providing a mountable surface for
flexographic printing plates. In a typical flexographic printing
press, the sleeve is mounted onto a printing cylinder using
pressurized air to expand the sleeve, and the printing plates are
then attached to the outer surface of the sleeve.
While thin metal sleeves for use on printing cylinders have been
employed in the past, more recently, printing sleeves have been
developed which are comprised of polymeric materials. For example,
printing sleeves are known which include laminated polymeric layers
reinforced with a woven or nonwoven fabric layer. Such sleeves
provide an advantage over metal rollers in that they are readily
expandable for mounting on a cylinder, are seamless, and provide
good structural integrity for printing operations without the
damage and safety limitations of thin metal sleeves. However, such
sleeves are typically expensive and slow to fabricate as each
component must be formed and cured separately and then assembled or
formed into a composite. Further, many polymeric printing sleeves
in use require specific polymers and/or cure temperatures, which
restricts the choice of materials or properties of the finished
sleeve surface which may be desired for different printing
applications.
Accordingly, there is still a need in the art for a replaceable
sleeve which is readily mountable on a cylinder or other carrier,
which may be fabricated quickly and easily, and which may be used
in a wide variety of applications including printing applications
as well as web or sheet handling or and/or processing applications
and the like.
SUMMARY OF THE INVENTION
The present invention meets that need by providing a replaceable
sleeve adapted to be mounted on a cylindrical carrier which is
comprised of a multilayer composite and which may be used in a
number of applications which typically utilize polymer covered
rolls including but not limited to web or sheet handling operations
and flexographic printing operations. The sleeve is efficiently
produced as the layers comprising the sleeve may be cured
simultaneously. The sleeve is essentially seamless, chemically
resistant, and may be easily mounted on a variety of carriers. When
used in printing operations, the sleeve provides high print quality
and performs within the tolerance levels required by the printing
industry.
According to one aspect of the present invention, a replaceable
sleeve is provided which is adapted to be mounted on a carrier. By
carrier, we mean any structure which functions to support the
sleeve during use and allows it to rotate during use including but
not limited to cylinders, tubes, and liners. The replaceable sleeve
is made up of a combination of layers including an inner polymeric
layer, a reinforcing layer overlying the inner layer, an
intermediate polymeric layer overlying the reinforcing layer, and
an outer polymeric layer forming a working surface, where the Shore
A hardness of the inner polymeric layer is generally equal to or
greater than the Shore A hardness of the intermediate and outer
polymeric layers. By working surface, we mean that the outer
surface of the sleeve may be adapted for a number of uses such as
printing, embossing, coating, calendering, etc.
Preferably, the inner layer, intermediate layer, and outer layer
are comprised of an elastomeric material selected from, but not
limited to, the group consisting of butyl rubber, nitrile rubber,
EPDM rubber, natural rubber, synthetic rubber, neoprene rubber, a
blend of nitrile rubber and polyvinyl chloride, and polyurethane.
Further, the inner layer, intermediate layer, and outer layer
preferably have a Shore A durometer hardness of from about 30 to
90.
In a preferred embodiment, the inner layer has a Shore A hardness
of at least about 70, and comprises, for example, a carboxylated
nitrile-butadiene copolymer. The inner layer enhances the
durability of the sleeve for repeated usage.
The reinforcing layer is preferably comprised of wound fibers of a
material selected from the group consisting of polyester, cotton,
fiberglass, cotton-wrapped polyester, rayon, carbon filaments, and
other high modulus synthetic or organic fibers.
In a preferred embodiment of the invention, the sleeve further
includes a cushion layer which may be positioned between the
intermediate polymeric layer and the outer surface layer which
functions to provide energy absorption and resiliency to the
sleeve. The cushion layer may be comprised of an open or
closed-cell polymeric foam or a polymer layer having a Shore A
durometer hardness of from about 25 to 55.
The outer polymeric layer functions both as a protective layer for
the cushion layer as well as providing a working surface having the
particular characteristics needed for a specific end use.
Preferably, each of the layers comprising the sleeve has a
thickness of from about 0.001 to 0.750 inches (0.0025 cm to 1.905
cm).
The present invention also provides a method of making the
replaceable sleeve of the present invention, which comprises the
steps of forming an inner layer of a hard polymeric material into a
cylindrical shape and mounting the layer on a support. A
reinforcing layer is applied over the outer surface of the inner
layer, and an intermediate polymeric layer is applied over the
outer surface of the reinforcing layer. An outer polymeric layer
may be applied over the outer surface of the intermediate polymeric
layer. The layers are then cured simultaneously in a single step to
form the sleeve. The layers are preferably cured at a temperature
of between about 285.degree. F. to 310.degree. F. (140.degree. C.
to 154.degree. C.) and for a time to effect vulcanization of all of
the layers.
The method also includes the optional step of applying a cushion
layer over the outer surface of the intermediate polymeric layer
prior to applying the outer layer. Where the cushion layer is
comprised of an open or closed-cell polymeric foam, the cellular
structure may be formed in a separate step prior to aplying the
outer layer.
The outer surface of the resulting sleeve may be further processed
as desired to provide a working surface for specific applications.
For example, the outer layer may be ground to provide a surface
roughness which is suitable for applications such as coating,
calendering, laminating, and the like, or which may be polished,
etched or engraved to provide a surface which may be used for
embossing or printing. The sleeve may be readily mounted and
dismounted from a carrier using pressurized air. In addition to the
printing and coating applications described above, the sleeve may
be used in any other applications which require the use of a
polymer covered roller, such as flood/solid color print rolls,
meter rolls, nip rolls, support rolls, and the like.
Accordingly, it is a feature of the present invention to provide a
replaceable sleeve having a working surface which may be readily
mounted on a carrier, which is easily fabricated, and which may be
used in a variety of applications. This, and other features and
advantages of the present invention will become apparent from the
following detailed description, the accompanying drawings, and the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, partially sectioned, of the
replaceable sleeve of the present invention mounted on a printing
cylinder;
FIG. 2 is a perspective view of the replaceable sleeve of FIG. 1;
and
FIG. 3 is a sectional view taken along lines 2--2 of FIG. 2.
FIG. 3A is a sectional view of an alternative embodiment of the
replaceable sleeve without a cushion layer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The replaceable sleeve of the present invention provides several
advantages over other prior sleeves that are covered with rubber or
polymer in that all of the layers comprising the sleeve are
seamless and may be cured in a single step, which allows the sleeve
to be produced more efficiently. And, because the layers comprising
the sleeve are not limited to the use of specific polymers or
curing methods, the properties of the sleeve may be tailored as
desired for specific applications. For example, where the sleeve is
used in printing operations, the outer layer of the sleeve may be
finished so that it can be used as the printing surface, thus
eliminating the requirement for the attachment of separate printing
plates. The sleeve of the present invention also offers the
advantage that it may be easily replaced on-site without having to
shut down processing equipment for extended periods of time. That
is, when the sleeve surface becomes worn or otherwise needs
replacement, the sleeve may be readily dismounted from its carrier,
and a new sleeve quickly mounted in its place.
Referring now to FIGS. 1 and 2, the replaceable sleeve 10 of the
present invention is shown. As shown in FIG. 1, the sleeve 10 is
mounted on a conventional printing cylinder 12. However, it will be
apparent to those skilled in the art that the sleeve may be adapted
to be mounted on a variety of other carriers. In one method,
cylinder 12 is hollow and may include an interior chamber (not
shown) which is used as a compressed air chamber through which air
may be passed for expanding the sleeve 10 during mounting and
dismounting operations. The cylinder may include a plurality of
spaced apart, radially-extending apertures 18 from which air in the
chamber may exit to or which may be used to expand the sleeve 10
during mounting and dismounting operations. The air is introduced
into the chamber by an air hose 14 which can communicate with the
apertures of the cylinder 12. The sleeve is typically mounted onto
the cylinder by introducing air at a pressure of about 80-120 psi
(5.6 to 8.4 kg/cm.sup.2) to expand the sleeve and permit it to be
slipped onto the cylinder.
FIG. 3A illustrates the layers comprising sleeve 10 including an
inner polymeric layer 20, a reinforcing layer 22 overlying inner
layer 20, an intermediate polymeric layer 24 overlying reinforcing
layer 22, and an outer polymeric layer 28. As shown, in FIG. 3 the
sleeve may optionally include a cushion layer 26 between outer
layer 28 and intermediate layer 24. Any suitable rubber adhesives
19 may be used to bond the layers together during vulcanization
including but not limited to CHEMLOK.TM., commercially available
from Lord Corporation.
The inner, intermediate, and outer polymeric layers of the sleeve
may be comprised of a number of different polymers including butyl
rubber, EPDM rubber, nitrile rubber, natural rubber, neoprene
rubber, a blend of nitrile and polyvinyl chloride, polyurethane,
and synthetic rubber. Suitable synthetic rubbers include
HYPALON.TM., a chlorosulfonated polyethylene available from DuPont.
Inner polymeric layer 20 is preferably comprised of a carboxylated
nitrile copolymer, which has a Shore A durometer hardness of
between about 65 to 90 after vulcanization. The hardness and
toughness of the inner layer provides abrasion resistance to the
sleeve and forms a sufficiently stable structure which provides
support for the remaining layers of the sleeve.
Reinforcing layer 22 provides additional dimension and support to
the sleeve, and is preferably comprised of wound fibers such as
polyester, cotton, fiberglass, cotton-wrapped polyester, rayon,
carbon filaments, or other high modulus synthetic or organic
fibers. Suitable synthetic fibers include aramid fibers available
from DuPont under the designation KEVLAR.RTM. and fiberglass or
polyester threads available from a variety of sources. Preferred
for use in the present invention are fiberglass fibers which have
been twisted into a cord or thread.
Cushion layer 26 provides cushion to the outer surface layer of the
sleeve. In instances where the sleeve is used in printing
operations, the cushion layer also provides cushion to the printing
plate that may be adhered to it. The cushion layer typically
comprises an open-celled polymeric foam or a layer of a soft
polymer having a Shore A durometer hardness of from about 25 to
55.
In the preferred method of making the sleeve of the present
invention, inner polymeric layer 20 is formed by either an
extrusion process in which the desired polymer is extruded as a
cylindrical tube through an extrusion die, or by calendering layers
of the polymer onto a mandrel. If the inner layer is formed by
extrusion into a tube, it is subsequently mounted onto a mandrel by
expansion with blown air. The mandrel is typically
cylindrically-shaped and may include a hollow internal chamber and
a plurality of holes on its outer surface to allow the passage of
pressurized air.
After the inner polymeric layer has been mounted or formed on the
mandrel, it remains in an uncured state. An adhesive is then
preferably applied to the inner layer to form an adhesive layer 19
prior to the application of reinforcing layer 22. The reinforcing
layer, which preferably comprises fiberglass or polyester twisted
cord, is then applied to the inner layer 20 by winding under
tension and wrapped around the layer at approximately 20 to 35
threads per linear inch. Another layer of adhesive is then
preferably applied over the reinforcing layer.
Intermediate layer 24 may be formed in the same manner as inner
layer 20, either by extrusion or calendering to produce a
substantially void-free layer as shown in FIG. 3. If formed by
extrusion, the intermediate layer is then mounted by expansion with
blown air onto the sleeve over adhesive layer 19.
In embodiments where cushion layer 26 is included in the structure,
another layer of adhesive may be applied over the intermediate
layer prior to application of the cushion layer. The cushion layer
may be formed by conventional means known in the art, and is
preferably formed by extruding the desired polymer with chemical
blowing agents which are activated during vulcanization. Suitable
chemical blowing agents include magnesium sulfate, hydrated salts,
hydrazides such as p-toluene sulfonyl hydrazide and
p,poxybisbenzene, sulfonyl hydrazide, and carbonamides such as
1,1'-azobisformamide. Nitrate, nitrite, bicarbonate and carbonate
salts may also be used. Alternatively, the cushion layer may be
formed in a separate step as disclosed in commonly-assigned U.S.
Pat. No. 4,548,858 to Meadows, the disclosure of which is hereby
incorporated by reference. In another alternative embodiment, the
cushion layer may be formed by mixing a suitable salt such as
hydrated magnesium sulfate with a polymeric material such as rubber
and then curing and leaching the salt out, forming cavities in the
rubber. Such a process is disclosed in commonly assigned U.S. Pat.
No. 3,928,521 to Haren et al, the disclosure of which is hereby
incorporated by reference. Still another method of forming the
cushion layer includes the incorporation of microcapsules in an
elastomeric matrix and fixing those microcapsules in a low
temperature partial vulcanization step as described in U.S. Pat.
No. 4,770,928 to Gaworoski, the disclosure of which is hereby
incorporated by reference.
Outer polymeric layer 28 is then formed, either by extrusion or
calendering as described above, and then mounted over the cushion
layer. A layer of adhesive may be applied to the cushion layer
prior to application of the outer layer.
The sleeve assembly is then preferably cured (at a temperature of
between about 285.degree. F. to 310.degree. F. (140.degree. C. to
154.degree. C.)), for a time sufficient to completely vulcanize
each layer in the sleeve in a single step. For sleeves of
relatively small dimension, a curing time of only about 45 minutes
may be needed, while for larger sleeves, a curing time of more than
6 hours may be required. This flexibility provides an advantage
over previous methods which require the same amount of curing time
regardless of the size of the sleeve.
It should be appreciated that while the sleeve described herein
preferably includes inner, intermediate, and outer polymeric layers
as well as a reinforcing layer and optional cushion layer, the
sleeve may also be constructed so that it comprises only the inner
layer, or only the inner layer, reinforcing layer, and intermediate
layer. The sleeve may also be fabricated to include only the inner
layer, reinforcing layer, intermediate layer and cushion layer.
Other variations of the layers comprising the sleeve are possible
and within the scope of the invention, as long as the sleeve
includes the inner hard polymeric layer.
The outer surface of the cured sleeve may then be finished as
desired by conventional means such as grinding and polishing to
provide proper surface conditions for printing or other
applications. In printing operations where printing plates are to
be mounted on the sleeve, the surface is preferably ground so as to
achieve a surface roughness of about 20 to 100 microinches
(5.multidot.10.sup.-5 cm to 2.5.multidot.10.sup.-4 cm). If the
outer surface layer of the sleeve is to be used as a printing
surface, the sleeve is preferably super polished to provide a
finish of from about 5 to 35 microinches (1.25.multidot.10.sup.-5
cm to 8.9.multidot.10.sup.-5 cm). The resulting sleeve is capable
of meeting tolerances required in the printing industry.
For other applications, the outer surface of the sleeve may further
be mechanically or chemically etched or laser engraved to provide a
suitable surface for transferring ink images onto a substrate, or
for other uses such as texturing, embossing, coating etc. It should
be appreciated that the properties of the sleeve may be tailored as
desired by modifying the materials used for each layer, as well as
by modifying the layer thickness and curing method.
The sleeve of the present invention can be readily mounted onto or
dismounted from any typical carrier such as cylinders, tubes,
liners, etc. In addition to printing operations, the sleeve of the
present invention may be used for any other applications which
typically utilize a polymer covered roll including coating,
tinting, embossing, laminating, impression, nip, and backup
rolls.
While certain representative embodiments and details have been
shown for purposes of illustrating the invention, it will be
apparent to those skilled in the art that various changes in the
methods and apparatus disclosed herein may be made without
departing from the scope of the invention, which is defined in the
appended claims.
* * * * *