U.S. patent application number 12/021001 was filed with the patent office on 2008-05-22 for solventless liquid isoprene compounds.
This patent application is currently assigned to Freudenberg-NOK General Partnership. Invention is credited to Paul J. HOCHGESANG.
Application Number | 20080116645 12/021001 |
Document ID | / |
Family ID | 26986637 |
Filed Date | 2008-05-22 |
United States Patent
Application |
20080116645 |
Kind Code |
A1 |
HOCHGESANG; Paul J. |
May 22, 2008 |
SOLVENTLESS LIQUID ISOPRENE COMPOUNDS
Abstract
In one embodiment, this invention relates to a solventless
liquid isoprene compound. The compound includes a liquid isoprene
rubber. The compound also includes a curing agent selected from
sulfur and/or sulfur donors. The curing agent is present in an
amount of at least about 3% by weight of the compound. The compound
contains substantially no solvent. In another embodiment, this
invention relates to a solventless liquid isoprene compound. The
compound includes a liquid isoprene rubber. The compound also
includes a nonsulfur curing agent. The curing agent is present in
an amount of at least about 5% by weight of the compound. The
compound contains substantially no solvent.
Inventors: |
HOCHGESANG; Paul J.; (Ann
Arbor, MI) |
Correspondence
Address: |
FREUDENBERG-NOK GENERAL PARTNERSHIP;LEGAL DEPARTMENT
47690 EAST ANCHOR COURT
PLYMOUTH
MI
48170-2455
US
|
Assignee: |
Freudenberg-NOK General
Partnership
Plymouth
MI
|
Family ID: |
26986637 |
Appl. No.: |
12/021001 |
Filed: |
January 28, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10329064 |
Dec 23, 2002 |
7335807 |
|
|
12021001 |
Jan 28, 2008 |
|
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60342239 |
Dec 21, 2001 |
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Current U.S.
Class: |
277/316 ;
525/236; 525/343 |
Current CPC
Class: |
C08L 9/00 20130101 |
Class at
Publication: |
277/316 ;
525/343; 525/236 |
International
Class: |
E04B 1/682 20060101
E04B001/682; C08F 36/08 20060101 C08F036/08; C08L 9/00 20060101
C08L009/00 |
Claims
1. A solventless liquid isoprene compound comprising: a liquid
isoprene rubber, polymer molecules thereof having a backbone
consisting of polyisoprene; and a curing agent selected from the
group consisting of sulfur, sulfur donors, and mixtures thereof,
where the curing agent is present in an amount of at least about 3%
by weight of the compound; the compound containing substantially no
solvent.
2. A compound according to claim 1 wherein the curing agent is
present in an amount between about 3% and about 10% by weight of
the compound.
3. A compound according to claim 1 wherein the liquid isoprene
rubber is present in an amount of at least about 40% by weight of
the compound.
4. A compound according to claim 1 additionally comprising a solid
isoprene rubber having a Mooney value of not more than about 75,
wherein the solid isoprene rubber is present in an amount of not
more than about 49% by weight of the total rubber.
5. A compound according to claim 1 which is readily flowable
between about 23.degree. C. and about 150.degree. C.
6. A flowable compound according to claim 1 which can be curable at
room or elevated temperature.
7. A compound according to claim 1 which is used as a curing
material for a sealing member.
8. A compound according to claim 1 which is used as a curing
material for a gasket selected from the group consisting of in
place gasketing (CIPG), inject in place gasketing (IJPG), and form
in place gasketing (FIPG).
9. A compound according to claim 1 which is used as a molding
material selected from the group consisting of liquid injection
molding (LIM), transfer molding (TM), and injection molding.
10-16. (canceled)
17. A compound according to claim 10 which is used as a curing
material for a sealing member.
18. A compound according to claim 10 which is used as a curing
material for a gasket selected from the group consisting of in
place gasketing (CIPG), inject in place gasketing (IJPG), and form
in place gasketing (FIPG).
19. A compound according to claim 10 which is used as a molding
material selected from the group consisting of liquid injection
molding (LIM), transfer molding (TM), and injection molding.
20. (canceled)
21. A sealing member made by a process comprising curing the
solventless liquid isoprene compound according to claim 1.
22. A sealing member according to claim 21, wherein the sealing
member is a gasket.
23. A gasket according to claim 22, wherein the gasket is a cure in
place gasket (CIPG), an inject in place gasket (IJPG), or a form in
place gasket (FIPG).
24. A gasket according to claim 22, wherein the gasket is a gasket
formed by liquid injection molding (LIM), a gasket formed by
transfer molding (TM), or a gasket formed by injection molding.
25. A sealing member according to claim 21, wherein the sealing
member is an O-ring.
26. A sealing member made by a process comprising curing the
solventless liquid isoprene compound according to claim 10.
27. A sealing member according to claim 26, wherein the nonsulfur
curing agent is a peroxide curing agent.
28. A sealing member according to claim 26, wherein the sealing
member is a gasket.
29. A gasket according to claim 28, wherein the gasket is a cure in
place gasket (CIPG), an inject in place gasket (IJPG), or a form in
place gasket (FIPG).
30. A gasket according to claim 28, wherein the gasket is a gasket
formed by liquid injection molding (LIM), a gasket formed by
transfer molding (TM), or a gasket formed by injection molding.
31. A sealing member according to claim 26, wherein the sealing
member is an O-ring.
32. A process for making a sealing member, comprising shaping and
curing the solventless liquid isoprene compound according to claim
1.
33. A process according to claim 32, comprising shaping and curing
by a method selected from the group consisting of cure in place
gasketing (CIPG), inject in place gasketing (IJPG), and form in
place gasketing (FIPG).
34. A process according to claim 32, wherein the sealing member is
shaped by a method selected from the group consisting of liquid
injection molding (LIM), transfer molding (TM), and injection
molding.
35. A process according to claim 32, comprising curing at a
temperature between 300.degree. F. and 400.degree. F.
36. A process for making a sealing member comprising shaping and
curing the solventless liquid isoprene compound according to claim
10.
37. A process according to claim 36, comprising shaping and curing
by a method selected from the group consisting of cure in place
gasketing (CIPG), inject in place gasketing (IJPG), and form in
place gasketing (FIPG).
38. A process according to claim 36, wherein the sealing member is
shaped by a method selected from the group consisting of liquid
injection molding (LIM), transfer molding (TM), and injection
molding.
39. A process according to claim 36, comprising curing at a
temperature between 300.degree. F. and 400.degree. F.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional
application Ser. No. 60/342,239, filed Dec. 21, 2001.
BACKGROUND OF THE INVENTION
[0002] This invention relates in general to elastomeric
compositions, and in particular to compounds made with a liquid
isoprene rubber.
[0003] Liquid isoprene rubbers are conventionally used in a minor
amount as a plasticizer or processing aid in combination with a
solid elastomer in preparing a rubber compound. It has not
previously been thought to use a liquid isoprene rubber as the base
elastomer for making a compound, and then to cure the liquid
isoprene rubber.
[0004] Rubber compounds are conventionally made by mixing the
elastomer(s) and other chemicals together in an organic solvent, or
in an aqueous solvent to prepare an emulsion. It has not previously
been thought to prepare a liquid isoprene rubber compound without
the use of a solvent, and there has been no suggestion how to
prepare the compound in a solventless process. Such a process is
contrary to the conventional thinking.
SUMMARY OF THE INVENTION
[0005] In one embodiment, this invention relates to a solventless
liquid isoprene compound. The compound includes a liquid isoprene
rubber. The compound also includes a curing agent selected from
sulfur and/or sulfur donors. The curing agent is present in an
amount of at least about 3% by weight of the compound. The compound
contains substantially no solvent.
[0006] In another embodiment, this invention relates to a
solventless liquid isoprene compound. The compound includes a
liquid isoprene rubber. The compound also includes a nonsulfur
curing agent. The curing agent is present in an amount of at least
about 5% by weight of the compound. The compound contains
substantially no solvent.
[0007] Various objects and advantages of this invention will become
apparent to those skilled in the art from the following detailed
description of the preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0008] The liquid isoprene compounds of the invention use liquid
isoprene rubbers as the base material for the compounds.
Surprisingly, the compounds are made with substantially no solvent,
e.g., not more than about 2% solvent. It has been discovered that
liquid isoprene compounds having excellent properties can be made
without solvent by using an increased amount of curing agent
compared to conventional methods.
[0009] The solventless liquid isoprene compounds of the invention
contain a liquid isoprene rubber, a curing agent, and optionally
other curing chemicals and other compounding ingredients as
described below.
The Liquid Isoprene Rubber
[0010] The liquid isoprene rubber can be any suitable type of
liquid isoprene-containing rubber. One nonlimiting example is
Claprene.RTM. L-1R-30, L-1R-50 or L-1R-503 manufactured by Kuraray
Co., Ltd., Kashima, Japan. Preferably, the liquid isoprene rubber
is present in an amount between about 40% and about 97% weight of
the compound.
Optional Solid Elastomer
[0011] In some applications, it may be desirable to add to the
compound a solid isoprene rubber having a Mooney value of not more
than about 75. A low Mooney isoprene rubber can be added to improve
the physical properties of the liquid isoprene rubber without
substantial loss in its flowability and processability. Preferably,
the amount of the solid isoprene rubber is not more than about 49%
by weight of the total rubber.
The Curing Agent
[0012] The curing agent (vulcanizing agent) can be any type
suitable for curing the liquid isoprene rubber. Some typical curing
agents include sulfur, sulfur donors, and nonsulfur curing agents
such as peroxides, metal oxides, difunctional resins, and amines.
Sulfur donors include sulfur-containing chemicals such as
tetramethylthiuram disulfide (TMTD), dipentamethylenethiuram
hexasulfide (DPTH), bis(2,2'-benzothiazolyl)disulfide or
benzothiazyldisulfide (MBTS), and dimorpholinyl disulfide
(DTDM).
[0013] Any suitable type of sulfur can be used. A nonlimiting
example of a suitable sulfur is Spider.RTM. brand sulfur
manufactured by C. P. Hall, Chicago, Ill.
[0014] Any suitable type of peroxide curing agent can be used. Some
nonlimiting is examples of peroxide curing agents are Varox.RTM.
DBPH-50, a 50% 2,5-dimethyl-2,5-di(t-butyl-peroxyl) hexane
manufactured by R.T. Vanderbilt Co., Norwalk, Conn.; Vul-Cup.RTM.
40KE manufactured by Hercules, Inc., Wilmington, Deleware;
Cadox.RTM. TS-50 manufactured by Akzo Chemical, Chicago, Ill.; and
MEK (methyl ethyl ketone) peroxides.
[0015] The liquid isoprene compounds contain an increased amount of
curing agent compared to conventional rubber compounds. When the
curing agent is a sulfur and/or a sulfur donor, the curing agent is
usually present in an amount of at least about 3% by weight of the
compound, and preferably between about 3% and about 10%. When the
curing agent is a nonsulfur curing agent, the curing agent is
usually present in an amount of at least about 5% by weight of the
compound, and preferably between about 5% and about 12%.
Other Curing Chemicals
[0016] The compounds can also optionally include other curing
chemicals, such as activators, crosslinking enhancers,
accelerators, and/or retarders. Any suitable type of activator can
be used. Some nonlimiting examples of activators are zinc oxide,
stearic acid, combinations of zinc oxide and stearic acid, other
metal oxides, other fatty acids, and phosphonium salts.
[0017] Any suitable type of crosslinking enhancer can be used. Some
nonlimiting examples are TAIC (triallyl isocyanurate), which is
manufactured by companies such as Nippon Kasei Chemical, Iwaki,
Japan, and Aldrich Chemical Co., Milwaukee, Wis.; Ricon.RTM. 152, a
homopolymer of butadiene (MW 2,900), which is manufactured by
Sartomer, Exton, Pa.; SR-351, trimethylol propane triacrylate,
manufactured by Sartomer, Exton, Pa.; and B5405, which is 75%
SR-350 (trimethylol propane trimethacrylate) and 25% inert filler
acting as a carrier.
[0018] If desirable, any suitable type of accelerator can be used.
Some nonlimiting examples of accelerators are
hexamethylenetetramine, mercaptobenzothiazoles, sulfenamides,
thiurams, dithiocarbamates, and guanidines. Also, any suitable type
of retarder can optionally be used. Some nonlimiting examples of
retarders are organic acids and anhydrides,
cyclohexylthiophthalimide, and sulfenamide.
Other Compounding Ingredients
[0019] The compounds can also optionally include other compounding
ingredients, such as fillers, bonding agents, antidegradants,
process oils, plasticizers, coloring agents, or other desirable
ingredients. Any suitable type of filler can be used. Some typical
fillers are carbon black, silica, and clay. Nonlimiting examples of
suitable fillers include Sterling.RTM. 6630 carbon black,
manufactured by Cabot Corporation, Alpharetta, Ga.; FK140 or FK160
silica manufactured by Degussa AG, Dusseldorf, Germany; and
CAB-O-SIL.RTM. TS-530, a hydrophobic fumed silica, manufactured by
Cabot Corp.
[0020] Some nonlimiting examples of bonding agents useful in the
compounds are resorcinol (1,3-dihydroxybenzene); and A-151, a vinyl
triethoxy silane, which is manufactured by Huayuan Fine Chemicals,
Wuhan, China.
[0021] Any suitable type of antidegradant can be used, such as
antioxidants, antiozonants, and heat stabilizers. Some typical
antioxidants are secondary amines, phenolics, and phosphites. A
nonlimiting example of a suitable antioxidant is Naugard.RTM. 445
antioxidant, which is a 4,4'-di(alpha,
alpha-dimethyl-benzyl)diphenylamine, manufactured by Uniroyal
Chemical Co., Waterbury, Conn.
[0022] Any suitable type of process oil can be used, such as
petroleum oils or vegetable oils. Some nonlimiting examples of
process oils include Sunpar.RTM. 2280 paraffinic oil, manufactured
by Nippon Sun Oil K.K., Japan; and Chevron ParaLux.RTM. Process Oil
6001R, a highly saturated white paraffinic process oil with very
low aromatic content, manufactured by ChevronTexaco Corp., San
Ramon, Calif. Also, any suitable type of plasticizer can be used,
such as petroleum oils.
[0023] Optionally, a coloring agent can be added to the compounds.
Some nonlimiting examples of coloring agents are man-made mineral
pigments such as the Geode.RTM. series (e.g., Geode.RTM. V-11633
Kelly Green); and the NEOLOR.RTM. series of inorganic pigments
(e.g., NEOLOR.RTM. Red S), both manufactured by Ferro Corp.,
Cleveland, Ohio.
Processing
[0024] The solventless liquid isoprene compounds can be processed
in any suitable manner. Typically, the chemicals are mixed together
using any suitable mixing equipment, such as planetary mixers
(e.g., Ross mixers), internal mixers, two-roll mills, open roll
mills or the like. The mixed compound is then applied, pressed, or
molded depending on the particular use. Then, the compound is cured
using any suitable time and temperature profile. Typically, the
compound is cured at a temperature between about 300.degree. F. and
about 400.degree. F. for a time between about 3 minutes and about
20 minutes. The compound can be further post cured if desired or
necessary, e.g., for 2 to 14 days at 70.degree. F. to 400.degree.
F.
Applications
[0025] The compounds of the invention can be used in many different
applications. Advantageously, the compounds are flowable so that
they can take the place of materials such as liquid silicones in
many applications. Preferably, the compounds have a viscosity not
more than about 50% greater than that of liquid silicones, more
preferably not more than about 25% greater, and most preferably not
more than about 10% greater, Unlike liquid silicones, the compounds
are impermeable to fluids, so their use is beneficial in
applications where it is desired to limit the flow of fluids, such
as in engine seals to limit the flow of VOC's through the engine.
The compounds are also easier to process than liquid silicones. The
flowability of the compounds allows them to be applied instead of
molded, which can save the costs typically associated with molding.
Of course, the compounds can also be molded if desired, and their
use is not limited to flowable applications.
[0026] Some nonlimiting examples of typical applications include
use as sealing members (e.g., gaskets, O-rings, packings or the
like) which can be used in many different applications, such as
sealing with respect to engine oil, gear oil, transmission oil, or
power steering fluid. For example, the compounds can be used for
cure in place gasketing (CIPG), inject in place gasketing (IJPG),
and form in place gasketing (FIPG). They can be applied robotically
thereby resulting in a dispensed sealing bead.
[0027] The compounds are suitable for making thin seals such as
thin layered gaskets, and for making intricate seals and gaskets.
They can be used to fill intricate channels in a metal plate. A
thin gasket can be injection molded onto a plastic or metal
carrier.
[0028] The compounds can be used in liquid injection molding (LIM),
transfer molding (TM), injection molding.
[0029] The compounds can be used to make rubber-coated metal (RCM)
products and rubber-coated plastic products. The compounds cure and
bond well to the metal and plastic.
[0030] The compounds can be used as a screen printing material.
Because of their low viscosity, lower pressures are required during
the forming process which allows for complicated manufacturing
using pressure sensitive material as an integral part of the
forming process.
[0031] The compounds can be used as a fabric coating in many
different applications, e.g., as a coating on airbags or interior
portions of airplanes. The compounds can be used as a repair
material, e.g., to fill in little holes in bumpers.
[0032] Since the compounds are solventless, they can be easily
applied by workers without the hazards of breathing in fumes. The
compounds can be applied by any suitable method. The compounds can
be applied and will cure at room temperature.
EXAMPLES
[0033] Some nonlimiting examples of compounds according to the
invention were prepared as follows: TABLE-US-00001 Liquid
IsopreneRubber 100.0 (IR 30) Varox DBPH 8.0 ZnO 1.5
[0034] TABLE-US-00002 IR 30 50 50 50 Silica 25 -- -- 6630 -- 25 25
Varox 4 4 4 ZnO 0.75 0.75 0.75 Pigment 0.5 -- -- Ricon 152 -- --
1.0
[0035] TABLE-US-00003 IR 30 50.0 50 6630 15.0 25 Varox 4.0 2 ZnO
0.90 0.9 B5405 1.0 1.0
[0036] TABLE-US-00004 IR 30 50 50 ZnO 0.9 0.9 Varox 2 2 FK 140 12
12 B5405 1 1 Blue Pigment 1 1 Rincon 152 2 TS-561 1.2
[0037] In accordance with the provisions of the patent statutes,
the principle and mode of operation of this invention have been
explained and illustrated in its preferred embodiment. However, it
must be understood that this invention may be practiced otherwise
than as specifically explained and illustrated without departing
from its spirit or scope.
* * * * *