U.S. patent application number 13/190736 was filed with the patent office on 2011-11-17 for elastomer composite materials in low density forms and methods.
Invention is credited to Glendon A. McConnell, Meng-Jiao Wang, Ting Wang.
Application Number | 20110281046 13/190736 |
Document ID | / |
Family ID | 21907277 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110281046 |
Kind Code |
A1 |
Wang; Ting ; et al. |
November 17, 2011 |
ELASTOMER COMPOSITE MATERIALS IN LOW DENSITY FORMS AND METHODS
Abstract
A bale of elastomer composite is formed of elastomer and filler;
the bale having a void volume of at least 3%. In another aspect, a
container is provided, at least a portion of the container being
occupied by elastomer composite pieces of elastomer and filler,
wherein the occupied portion of the container has a void volume of
at least 3%.
Inventors: |
Wang; Ting; (Billerica,
MA) ; McConnell; Glendon A.; (Rockford, IL) ;
Wang; Meng-Jiao; (Lexington, MA) |
Family ID: |
21907277 |
Appl. No.: |
13/190736 |
Filed: |
July 26, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12008187 |
Jan 9, 2008 |
8012390 |
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13190736 |
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10039774 |
Nov 9, 2001 |
7341142 |
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12008187 |
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Current U.S.
Class: |
428/35.2 ;
428/34.1; 521/134 |
Current CPC
Class: |
B29B 15/026 20130101;
Y10T 428/29 20150115; Y10T 428/1352 20150115; Y10T 428/13 20150115;
Y10T 428/249953 20150401; Y10T 428/1386 20150115; Y10T 428/1334
20150115 |
Class at
Publication: |
428/35.2 ;
521/134; 428/34.1 |
International
Class: |
B32B 1/02 20060101
B32B001/02; C08L 101/00 20060101 C08L101/00 |
Claims
1-20. (canceled)
21. A method of producing an elastomer composite blend, the method
comprising: blending a bale of elastomer composite pieces having a
void volume of at least 3% with additional elastomer material
comprising at least additional elastomer, to form an elastomer
composite blend.
22-24. (canceled)
25. A method of producing an elastomer composite blend in
accordance with claim 21, wherein the additional elastomer
comprises elastomer different from the elastomer of the elastomer
composite.
26. A method of producing an elastomer composite blend in
accordance with claim 21, wherein the step of blending the bale of
elastomer composite with the additional elastomer material
comprises dry mixing the bale of elastomer composite with the
additional elastomer material.
27. A method of producing an elastomer composite blend in
accordance with claim 21, wherein the additional elastomer material
comprises additional filler.
28. A method of producing an elastomer composite blend in
accordance with claim 21, wherein the bale of elastomer composite
includes at least one additive selected from the group consisting
of: antiozonants, antioxidants, plasticizers, processing aids,
resins, flame retardants, extender oils, lubricants, cure
activators, and combinations thereof.
29-33. (canceled)
34. A container wherein at least a portion of the container is
occupied by elastomer composite pieces comprising an elastomer and
filler, and wherein the occupied portion of the container has a
void volume of at least 3%.
35. A container in accordance with claim 34, wherein the occupied
portion of the container has a void volume of approximately 3% to
approximately 40%.
36. A container in accordance with claim 34, wherein the elastomer
composite pieces have a Mooney viscosity of at least 100.
37. A container in accordance with claim 34, wherein the elastomer
composite pieces have a generally planar form.
38. A container in accordance with claim 34, wherein the elastomer
composite pieces have the form of short strips.
39. (canceled)
40. A container in accordance with claim 34, wherein the elastomer
composite pieces have the form of pellets.
41. (canceled)
42. A container in accordance with claim 34, wherein the container
is a bag, a drum, or a box.
43-52. (canceled)
53. A method of producing an elastomer composite blend, the method
comprising providing a container wherein at least a portion of the
container is occupied by elastomer composite pieces and wherein the
occupied portion of the container has a void volume of at least 3%;
and blending the elastomer composite pieces with additional
elastomer material comprising at least additional elastomer, to
form an elastomer composite blend.
54-55. (canceled)
56. A method of producing an elastomer composite blend in
accordance with claim 53, wherein the additional elastomer
comprises elastomer different from the elastomer of the elastomer
composite.
57. A method of producing an elastomer composite blend in
accordance with claim 53, wherein the step of blending the
elastomer composite pieces with the additional elastomer material
comprises dry mixing the elastomer composite pieces with the
additional elastomer material.
58. A method of producing an elastomer composite blend in
accordance with claim 53, wherein the additional elastomer material
comprises additional filler.
59. A method of producing an elastomer composite blend in
accordance with claim 53, wherein the elastomer composite pieces
include at least one additive selected from antiozonants,
antioxidants, plasticizers, processing aids, resins, flame
retardants, extender oils, lubricants, cure activators, and
combinations thereof.
60-64. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to methods for treating
elastomer composites, and to low density forms of elastomer
composites.
BACKGROUND
[0002] Various industries utilize elastomeric compounds including
fillers, e.g., particulate fillers, dispersed in suitable
elastomer, especially, for example, carbon black dispersed in
natural rubber. There is a need for such elastomeric compounds to
be easy to work with, such that a user can easily process the
elastomeric compounds in production equipment used to make other
end products, e.g., tires. Such production equipment includes, for
example, Banbury mixers. Elastomeric compounds of high viscosity
and high density are hard to work with, and, therefore, may not be
suitable for use in equipment such as Banbury mixers, or other
production equipment.
SUMMARY OF THE INVENTION
[0003] In accordance with a first aspect of the invention, there is
provided a bale of elastomer composite comprising elastomer
composite pieces, wherein the elastomer composite pieces comprise
an elastomer and filler and wherein the bale has a void volume of
at least 3%.
[0004] In accordance with another aspect of the invention, there is
provided a method of producing a bale of elastomer composite
comprising the steps of mixing an elastomer latex with a filler to
form an elastomer composite, treating the elastomer composite to
form elastomer composite pieces, and forming the elastomer
composite pieces into a bale having a void volume of at least 3%. A
preferred method of forming the elastomer composite pieces into a
bale is by compression.
[0005] In accordance with another aspect of the invention, there is
provided a method of producing an elastomer composite blend
comprising the steps of blending a bale of elastomer composite
pieces having a void volume of at least 3% with additional
elastomer material comprising at least additional elastomer, to
form an elastomer composite blend.
[0006] In accordance with another aspect of the invention, there is
provided a container wherein at least a portion of the container is
occupied by elastomer composite pieces comprising an elastomer and
filler, and wherein the occupied portion of the container has a
void volume of at least 3%.
[0007] In accordance with another aspect of the invention, there is
provided a method of packaging elastomeric composite pieces in a
container wherein at least a portion of the container is occupied
by elastomer composite pieces comprising the steps of mixing an
elastomer latex with filler to form an elastomer composite,
treating the elastomer composite to form elastomer composite
pieces, and packaging the elastomer composite pieces in a container
such that the occupied portion of the container has a void volume
of at least 3%.
[0008] In accordance with another aspect of the invention, there is
provided a method of producing an elastomer composite blend
comprising the steps of providing a container wherein at least a
portion of the container is occupied by elastomer composite pieces
and wherein the occupied portion of the container has a void volume
of at least 3%, and blending the elastomer composite pieces with
additional elastomer material comprising at least additional
elastomer, to form an elastomer composite blend.
[0009] These and other aspects and advantages of various
embodiments of the invention will be further understood in view of
the following detailed discussion of certain preferred
embodiments.
DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS
[0010] The following is a detailed description of certain preferred
embodiments of the present invention and is not intended to limit
the present invention to the embodiments described below.
[0011] Novel and useful materials formed in accordance with certain
preferred embodiments of the present invention include bales of
elastomer composite pieces formed of elastomer and filler and
having a void volume of at least 3%, and elastomer composite pieces
within a container where a unit volume of the elastomer composite
pieces has a void volume of at least 3%. Such materials
advantageously are easy, to work with such that a user can process
such materials in production equipment used to make other
intermediate or end products. Suitable techniques for preparing
such materials are discussed in greater detail below.
[0012] In accordance with certain preferred embodiments, elastomer
latex and filler may be mixed and coagulated to form elastomeric
composites, described in greater detail below. Optionally, the
elastomer composite may undergo intermediate processing steps,
including, for example, processing in a mixer or compounder, such
as a continuous mixer or compounder, to provide elastomer composite
having reduced Mooney viscosity, and improved control of molecular
weight, bound rubber and water content. Such processed elastomer
composite is also referred to herein as compounded elastomer
composite. The elastomer composite is treated to form elastomer
composite pieces. Such elastomer composite pieces are baled or
containerized such that the void volume of the bale or the portion
of the container occupied by the elastomer composite pieces is at
least 3%. It should be understood that the term "bale of elastomer
composite," unless otherwise clear from context, refers to a bale
formed of elastomer composite pieces as described above.
[0013] As noted above, the novel materials of the invention can be
prepared by incorporating methods of producing elastomer composite
formed of elastomer and filler, such as mixing and coagulating.
Preferred methods and apparatus for producing the elastomer
composites are described in the commonly assigned U.S. Pat. Nos.
6,075,084, 6,048,923, and 6,040,364, and commonly assigned U.S.
patent application Ser. No. 09/549,051, the entire disclosure of
each of which is hereby incorporated herein by reference for all
purposes. U.S. Pat. No. 6,040,364 and U.S. Pat. No. 6,048,923
describe methods for producing elastomer composites, referred to
here in some instances as wet impact coagulation, comprising
feeding a continuous flow of first fluid comprising elastomer latex
to a mixing zone of a coagulum reactor defining an elongate
coagulum zone extending from the mixing zone to a discharge end,
and feeding a continuous flow of second fluid comprising a filler,
e.g., a particulate filler, under pressure to the mixing zone of
the coagulum reactor to form a mixture with the elastomer latex.
The mixture passes as a continuous flow to the discharge end of the
coagulum reactor, and the particulate filler is effective to
coagulate the elastomer latex. More specifically, the second fluid
is fed against the first fluid within the mixing zone sufficiently
energetically to substantially completely coagulate the elastomer
latex with the particulate filler prior to the discharge end of the
coagulum reactor. A substantially continuous flow of elastomer
composite is discharged from the discharge end. As noted above,
these processes are referred to below in some instances as wet
impact coagulation.
[0014] In certain preferred embodiments, particulate filler slurry
is fed to the mixing zone preferably as a continuous, high velocity
jet of injected fluid, while the latex fluid typically is fed at
relatively lower velocity. The high velocity, flow rate and
particulate concentration of the filler slurry are sufficient to
cause mixture and high shear of the latex fluid, flow turbulence of
the mixture within at least an upstream portion of the coagulum
zone, and substantially complete coagulation of the elastomer latex
prior to the discharge end. Substantially complete coagulation can
thus be achieved, in accordance with preferred embodiments, without
the need of employing an acid or salt coagulation agent. Preferred
continuous flow methods for producing the elastomer composites
comprise continuous and simultaneous feeding of latex fluid and
filler slurry to the mixing zone of the coagulum reactor,
establishing a continuous, semi-confined flow of a mixture of the
latex and filler slurry in the coagulum zone. Elastomer composite
crumb in the form of "worms" or globules are discharged from the
discharge end of the coagulum reactor as a substantially constant
flow concurrently with the on-going feeding of the latex and carbon
black slurry streams into the mixing zone of the coagulum
reactor.
[0015] In the described methods employing wet impact coagulation,
feed rates of latex fluid and particulate filler fluid to the
mixing zone of the coagulum reactor can be precisely metered to
achieve high yield rates, with little free latex and little
undispersed filler in the product crumb at the discharge end of the
coagulum reactor. Extremely high feed velocity of the particulate
filler fluid into the mixing zone of the coagulum reactor and
velocity differential relative to the latex fluid feed are believed
to be significant in achieving sufficient turbulence, i.e.,
sufficiently energetic shear of the latex by the impact of the
particulate filler fluid jet, for thorough mixing and dispersion of
the particulate into the latex fluid and coagulation. Prior
techniques involving premixing of latex and particulate filler,
such as in the above-mentioned Heller et al patent and Hagopian et
al patent, do not recognize the possibility of achieving
coagulation without exposing the latex/particulate mixture to the
usual coagulant solution with its attendant cost and waste disposal
disadvantages.
[0016] High mixing energies yield elastomer composite crumb with
excellent dispersion. The particulate filler fluid and elastomer
latex are fed preferably continuously and simultaneously, meaning
that an ongoing flow of coagulated masterbatch is established from
the mixing zone to the discharge end of the coagulum reactor while
an uninterrupted flow of the feed fluids is maintained. Modified
and alternative suitable methods for producing the elastomer
composites disclosed herein will be apparent to those skilled in
the art, given the benefit of this disclosure.
[0017] As noted above, the elastomer composite may optionally be
further processed to produce elastomer composite having reduced
Mooney viscosity and improved control of molecular weight, bound
rubber and water content. Suitable equipment for such further
processing includes, for example, a mixer or compounder, such as a
continuous mixer or compounder. Suitable continuous mixers or
compounders are well known and commercially available, including,
for example, the Unimix Continuous Mixer from Farrel Corporation of
Ansonia, Conn. U.S. patent application Ser. No. 09/549,051
describes further processing of elastomer composites through the
use of a continuous mixer or compounder.
[0018] Whether or not the elastomer composite is processed by a
mixer or compounder, the elastomer composite is further treated to
form elastomer composite pieces. In certain preferred embodiments,
the elastomer composite is fed to an open mill, or roll mill as,
for example, a length of extrudate exiting a continuous mixer or
compounder, and may be cut into smaller lengths prior to entering
the open mill. The elastomer composite may optionally be fed to the
open mill via a conveyor such as a conveyor belt, conduit, pipe, or
other suitable means for transporting the elastomer composite from,
for example, a continuous mixer or compounder to the open mill. The
open mill typically comprises a pair of rollers that further
control the Mooney viscosity of the elastomer composite. The
rollers may optionally be heated or cooled to provide enhanced
operation of the open mill. In certain embodiments, the open mill
may reduce the temperature of the elastomer composite to
approximately 100.degree. C.
[0019] After exiting the open mill, the elastomer composite
optionally may be fed by a conveyor to a cooling system that may
include a cooling water spray, with its water being fed from a
cooling water tank or other water source. The water from the
cooling water spray may be sprayed directly onto the elastomer
composite. If cooling water spray has been used, optionally an air
knife or other high pressure air blower or other suitable means can
be used to remove any cooling water that did not evaporate from the
elastomer composite.
[0020] In certain preferred embodiments, the composite pieces may
have a substantially planar form. Suitable planar composite pieces
may be formed from sheets that are cut into smaller strips or
pieces. Planar, as used herein, refers to materials that preferably
have a width and/or length which is greater than the thickness of
the material. It is to be appreciated that the surface of the
composite pieces may not be entirely smooth, and may contain
irregularities, and bar the term planar refers to the overall
dimensions of the composite pieces.
[0021] In certain preferred embodiments, pieces of elastomer
composite may be formed by using a granulator, which cuts the
elastomer composite into short strips that are more easily handled
by traditional rubber industry processes and equipment. In certain
preferred embodiments, the elastomer composite exiting the open
mill in sheet form may be cut longitudinally into long strips,
which are fed into the granulator. The granulator may then cut the
long strips transversely into smaller strips. The strips produced
by a granulator may, therefore, constitute the end product, and be
used directly in industry processes and equipment. In certain
preferred embodiments, the strips formed by a granulator have a
length of approximately 40 mm to 60 mm, a width of approximately 5
mm to 10 mm, and a thickness of approximately 5 mm to 10 mm.
Suitable granulators will become readily apparent to those skilled
in the art, given the benefit of this disclosure.
[0022] In certain preferred embodiments, the granulator may be, for
example, a pelletizer. A pelletizer will convert the elastomer
composite into small pellets that can also be easily handled by
typical industry processing equipment For example, the pelletizer
may extrude the elastomer composite through a die and cut it into
small cylindrical pellets. In certain preferred embodiments, the
pellets have a diameter of approximately 5 mm to 10 mm and a length
of approximately 10 mm to 30 mm. The elastomer composite pieces may
be formed of other shapes as well, depending on the shape of the
die and the method of granulating. Another exemplary pelletizer
would consist of a spinning blade within a container that cuts the
elastomer composite into small pellets. Suitable pelletizers will
become readily apparent to those skilled in the art, given the
benefit of this disclosure.
[0023] Preferably, composite elastomer pieces prepared in
accordance with the present invention will have a size suitable for
further processing in certain production environments. Other
devices for converting the elastomer composite into composite
pieces suitable for further processing will become readily apparent
to those skilled in the art, given the benefit of this
disclosure.
[0024] The elastomer composite pieces can then optionally be fed,
e.g. by conveyor, to a baler, where the elastomer composite,
preferably under compression, can be baled more or less tightly or
densely by varying the dwell time, that is, the pressure and time
in the baler, depending on its intended use. The term "bale", as
used herein, refers to material that is form-retaining in the free
state. Optionally, the bale may be bound or wrapped. In certain
production environments, baled elastomer composite may be of a
density, hardness, and/or Mooney viscosity higher than desirable
for processing. For example, in the production of tires or other
products, certain process equipment, e.g., Banbury mixers and the
like, cannot readily process the baled product due to high density,
hardness and/or Mooney viscosity. Additional processing is often
required in order to make the elastomer composite suitable for
processing. Such additional processing may include additional
mastication of the elastomer composite, and, therefore, potential
over-mastication of the composite, which may adversely affect
desired characteristics and operating parameters of the elastomer
composite.
[0025] In order to allow the industry equipment to process the
bales, the bales of the present invention are preferably formed as
loose bales, that is, having a higher void volume. A suitable loose
bale preferably has a void volume of at least 3%, and, more
preferably, between approximately 3% to 40%, and, most preferably
between approximately 5% and 20%. Suitable baling equipment will be
apparent to those skilled in the art, given the benefit of this
disclosure.
[0026] The phrase "void volume", as used herein, refers to the
percent volume of voids, that is, air gaps, spaces, or interstices,
in a bale or occupied portion of a container of elastomer composite
pieces. In the case where the elastomer composite pieces are baled,
the void volume can be determined by subtracting the volume of the
elastomer composite pieces (which can be calculated from the total
weight of the pieces and the material density, as weight per unit
volume) from the total volume of the bale. The result is then
divided by the total volume of the bale and multiplied by 100 to
get the percentage. Thus, for a bale, the void volume is the volume
of the voids in the bale, divided by the volume of the bale,
multiplied by 100. Since the void volume of the elastomer composite
pieces in a bale is considered to include the volume between
pieces, or inter-pieces, it would include the volume of
irregularities found on the surfaces of the elastomer composite.
However, the void volume would not be considered to include .voids
found within the elastomer composite pieces themselves, that is, it
would not include intra-piece voids (such as bubbles within the
pieces).
[0027] The higher void volume a particular bale has, the easier it
will be for process equipment to handle the elastomer composite.
Consequently, even for elastomer composite having a relatively high
Mooney viscosity and/or density, a loosely packed bale with a
substantial or high void volume may easily be processed by
production equipment, such as a Banbury mixer or the like. In
mixing equipment such as a Banbury mixer, processing of elastomer
composite material that does not have the void volume of the
present invention leads to a very high initial torque, resulting in
processing problems and possible equipment failure. Through the use
of elastomer composite material processed in accordance with the
present invention and having a desired void volume, the initial
torque required to operate a mixer such as a Banbury mixer is
significantly reduced, leading to improved processing of the
elastomer composite and, therefore, reduced equipment problems and
failures. This can result in significant energy savings and cost
benefits.
[0028] To produce a bale of elastomer composite pieces of a desired
void volume, the pressure, temperature and time in the baler can be
varied. The pressure and temperature are adjusted such that the
value of each is sufficient to achieve a desired void volume for a
bale. It is generally the rule that temperature and pressure will
vary inversely with one another. Suitable pressures, temperatures
and times will become readily apparent to those skilled in the art,
given the benefit of this disclosure.
[0029] In other preferred embodiments, the elastomer composite
pieces travel via a conveyor directly to a container and are not
baled. The container may be, for example, a bag, a drum, a box, or
any other container suitable for carrying elastomer composite
pieces. The pieces of elastomer composite are packaged in the
container such that the occupied portion of the container--that is,
the portion of the container filled with elastomer composite
pieces--has a void volume of at least 3%, more preferably, between
approximately 3% and 40%, and, most preferably between
approximately 5% and 30%. The void volume of the container of
elastomer composite pieces can be determined in a manner similar to
that described above for a bale. However, only that portion of the
container that is occupied by the elastomer composite pieces is
considered in determining the void volume. Thus, if the container
is, for example, only half filled, the head-space above the filled
region is not considered. The void volume is therefore determined
by subtracting the volume of the elastomer composite pieces from
the total volume of the container occupied by composite pieces,
dividing the result by that occupied volume, and multiplying by
100. Again, when measuring the void volume of the container, any
air space above the upper level of the elastomer composite pieces
within the container is not to be considered when calculating the
void volume of the container of elastomer composite pieces.
[0030] The size, shape, and distribution of the voids may vary
within the bale or occupied portion of the container. Preferably
the voids are substantially evenly distributed throughout the bale
or occupied portion of the container.
[0031] The elastomer composite may optionally be treated with an
anti-tack material such as, for example, an aqueous solution of
zinc stearate, an aqueous silicate solution, or other suitable
anti-tack materials which will become readily apparent to those
skilled in the art, given the benefit of this disclosure. The
anti-tack material may be applied to the elastomer composite in a
dip tank, sprayed on, or applied in any other suitable fashion.
Appropriate equipment for the application of anti-tack material to
the elastomer composite will become readily apparent to those
skilled in the art, given the benefit of this disclosure. It is to
be appreciated that the anti-tack material may be applied to the
elastomer composite at numerous points during its processing,
including, for example, when it is in sheet form prior to it being
slit and cut into composite pieces, just after it is slit into
strips, or when in it is in its final form as composite pieces.
[0032] Elastomer composite in accordance with preferred embodiments
of the present invention preferably has a Mooney viscosity in its
baled or containerized form of at least 100 and more preferably
approximately 100-120. It has been found that a bale or container
of elastomer composite pieces having a void volume of at least 3%
enables an elastomer composite with a high Mooney viscosity to be
more suitable for processing. This represents a substantial
improvement in the art, since materials which were thought to be
difficult to process are now, through this disclosure, able to be
processed.
[0033] In certain preferred embodiments, the elastomer composite
may flow from a continuous compounder through an open mill, a
cooling system and a granulator to form a final elastomer composite
product in composite piece form that is packaged in a container
having a void volume suitable for further processing. Optionally,
the composite pieces may then be further processed by a baler to
form loose bales having a void volume suitable for further
processing. As noted above, in either of these two embodiments, the
granulator may be a pelletizer, or other suitable device, for
converting the elastomer composite into composite pieces suitable
for further processing.
[0034] The open mill can be expensive to operate due to high energy
consumption and its labor intensive operation. Thus, in other
preferred embodiments, the elastomer composite may flow from the
continuous compounder directly to a granulator to form a final
elastomer composite product in composite piece form. Optionally,
the composite pieces may then be further processed by a baler to
form loose bales having a void volume suitable for processing by
additional process equipment. In either of these two embodiments,
the granulator may be a pelletizer, or other suitable device, for
converting the elastomer composite into composite pieces suitable
for further processing.
[0035] It is to be appreciated that a cooling system may optionally
be placed downstream of the granulator or pelletizer, or omitted
entirely from the process.
[0036] In certain preferred embodiments, an elastomer composite
blend can be formed in a mixing device, such as a Banbury mixer or
the like. A bale of elastomer composite formed in a baler, or
elastomer composite pieces themselves, are placed in a mixing
device. Additional elastomer material from a reservoir or other
source is added to the mixing device. The addition of elastomers
can produce elastomer blends via the mixing device. Exemplary
elastomers include, but are not limited to, rubbers, polymers
(e.g., homopolymers, copolymers and/or terpolymers) of
1,3-butadiene, styrene, isoprene, isobutylene,
2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, and propylene
and the like.
[0037] Additives may also be introduced into the mixing device.
Exemplary additives include, for example, filler (which may be the
same as, or different from, the filler used in the coagulum
reactor, exemplary fillers including silica and zinc oxide, with
zinc oxide also acting as a curing agent), other elastomers, other
or additional composite, antioxidants, antiozonants, plasticizers,
processing aids (e.g., stearic acid, which can also be used as a
curing agent, liquid polymers, oils, waxes, and the like), resins,
flame-retardants, extender oils, lubricants, cure activators (e.g.,
zinc oxide or stearic acid) and a mixture of any of them. It is to
be appreciated that any combination of elastomers, additives and
second composite may be added in the mixing device to the bale or
pieces of elastomer composite.
[0038] In view of the foregoing disclosure, it will be apparent to
those skilled in the art that various additions, modifications,
etc. can be made without departing from the true scope and spirit
of the invention. All such additions and modifications are intended
to be covered by the following claims.
* * * * *