Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-01-15
2004-09-28
Cain, Ed (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S494000
Reexamination Certificate
active
06797762
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a rubber composite made from an elastomer polymerized on the surface of a silanized filler, a rubber composition containing such composite and an article such as for example a tire, which has at least one component comprised of such composition. Such reinforcement is applied by polymerizating a conjugated diene hydrocarbon in the presence of a filler silanized with an alkenyl silane. In particular a silanized reinforcing filler is pre-treated with butyl lithium or peroxide catalyst, preferably with butyl lithium, followed by polymerizing a conjugated diene hydrocarbon in the presence of such treated filler via an anionic or a free radical polymerization in an organic solvent. Such pre-formed elastomer composite is also contemplated as well as a rubber composition comprised of a blend of such pre-formed composite and at least one additional elastomer. Such filler may be, for example, precipitated silica, carbon black and/or a modified carbon black. A tire having a component of such composite or rubber composition such as, for example a tread, is also provided.
BACKGROUND OF THE INVENTION
Tires are typically prepared of treads of elastomer based rubber compositions which are conventionally carbon black reinforced. Sometimes tire tread rubber compositions are also silica reinforced often with an inclusion of a coupling agent to aid in coupling the reinforcing filler to the rubber.
It is sometimes desired to enhance a homogeneous dispersion of the reinforcing filler in the rubber composition such as, for example, by for efficient or more prolonged mixing of the rubber composition or by other means.
According to WO96/34900 patent publication, a polyolefin composite might be prepared by polymerizing olefin(s) in the presence of
(A) a transition metal catalyst,
(B) co-catalyst or activator for said transition metal catalyst, and
(C) filler.
The product is said to be obtainable as free flowing particles which may be processed into shaped articles such as, for example, injection molding, rotational molding, compression molding, profile extrusion, flat-die film extrusion and co-extrusion.
However, it is desired herein to produce elastomeric compositions containing integral reinforcing fillers via an anionic or a free radical polymerization, a polymerization route not addressed by the above patent publication routes. The free radical polymerization might sometimes be referred to as a radicalar polymerization.
The term “phr” where used herein, and according to conventional practice, refers to “parts of a respective material per 100 parts by weight of rubber, or elastomer”.
In the description of this invention, the terms “rubber” and “elastomer” where used herein, may be used interchangeably, unless otherwise prescribed. The terms “rubber composition”, “compounded rubber” and “rubber compound”, if used herein, are used interchangeably to refer to “rubber which has been blended or mixed with various ingredients and materials” and such terms are well known to those having skill in the rubber mixing or rubber compounding art.
SUMMARY AND PRACTICE OF THE INVENTION
In accordance with this invention, a method of preparing a diene-based elastomer/filler composite, namely, a pre-formed elastomer containing an integral filler dispersion therein, comprises
(A) polymerizing at least one conjugated diene hydrocarbon selected from isoprene, 1,3-butadiene and mixtures thereof or copolymerizing at least one conjugated diene selected from isoprene and 1,3-butadiene, and mixtures thereof, styrene in an organic solvent and in the presence of at least one treated particulate filler selected from at least one of precipitated silica, and modified carbon black;
(B) terminating the polymerization reaction; wherein said elastomer composite contains from about 10 to about 100 phr of said filler;
wherein said treated filler is treated by
(1) first treating said filler to silanize said filler with an organosilane of the general formula (I):
wherein R
1
, R
2
and R
3
are equal or individually and independently selected from CH
3
—, H—, Cl— and (—OR
6
) and R
6
is individually selected from methyl, ethyl and propyl radicals, preferably an ethyl radical and R
4
is a —CH
2
— radical, n is an integer of zero or one, wherein if n is one then R
4
is selected from an aryl radical, an alkenylaryl radical, an alkenylarylalkyl radical or an alkylaryl radical, and R
5
is selected from an —(CH═CH
2
) radical, an acrylate or a methacrylate radical followed by
(2) treating said silanized filler with said a polymerization initiator selected from butyl lithium, tetramethyl ethylenediamine or peroxide, respectively, initiators of organic solvent anionic and radicalar, as the case may be, diene-based monomer polymerizations.
A significant aspect of this invention is to initiate (start) the polymerization from the filler surface using anionic or radicalar polymerization systems. This aspect of the invention is considered herein to be significant because it improves polymer/filler interaction which is critical to rubber compound performances (tire and non-tire applications).
Representative examples of said organosilanes of formula (I) are, for example: 3-acryloxypropyl-trimethoxy silane; SIA0200.0 Methacryloxymethyl trimethoxy silane (SIM6483.0), methacryloxymethyl triethoxy silane (SIM6482.0), methacryloxymethyl trimethyl silane (SIM6485.6), allyltriethoxysilane (SIA0525.0), allyltrimethoxysilane (SIA0540.0), 5-(biscycloheptenyl)triethoxysilane (SIB0992.0), 3-butenyltriethoxysilane (SIB1928.0), [2-(3-cyclohexenyl)ethyl]trimethoxysilane (SIC2460.0), 3-(cyclopentadienylpropyl)triethoxysilane (SIC2520.0), 3-acryloxypropyl-methyldichlorosilane (SIA0196.0), 3-acryloxypropyl-dimethylmethoxysilane (SIA0190.0), 3-acryloxypropyl-trichlorosilane (SIA0199.0), allylmethyldichlorosilane (SIA0470.0), allyldimethylsilazane (SIA0464.0), 5-(biscycloheptenyl)dimethylchlorosilane (SIB0994.0), 3-butenylmethyldichlorosilane (SIB1926.0), [2-(3-cyclohexenyl)ethyl] dimethylchlorosilane (SIC2457.0), [2-(3-cyclohexenyl)ethyl]trichlorosilane (SIC2459.0), 3-(cyclpentadienyl)trimethylsilane (SIC2522.0), styrylethyl trimethoxysilane (SIS6990.0).
The above organosilanes are referenced according to their catalog numbers from the Gelest catalogue from ABCR GmbH & Co. in D-76151 Karlsruhe Germany P.O. Box 210135.
The invention further contemplates an elastomer composite prepared by the method of this invention.
The invention further contemplates a rubber composition comprised of the said elastomer composite of this invention and at least one additional diene-based elastomer. Such additional diene-based elastomer may be, for example, polymers of isoprene, 1,3-butadiene and mixtures thereof and copolymers of isoprene, 1,3-butadiene and mixtures thereof with styrene.
The invention also contemplates an article of manufacture having at least one component as a rubber composition comprised of said elastomer composite or of said rubber composition which contains said elastomer composite.
The invention additionally contemplates a tire having at least one component as a rubber composition comprised of said elastomer composite or of said rubber composition which contains said elastomer composite.
The carbon black filler for this invention is a rubber reinforcing carbon black, as would be understood by one having skill in the rubber compounding art. Examples of such carbon blacks are described in
The Vanderbilt Rubber Handbook
, 13th Edition, and Pages 417 and 418.
In another aspect of the invention, the modified carbon black filler is such a carbon black which has been treated to contain at least one moiety selected from silanol, siloxane, titanium oxide, titanium hydroxide, zirconium oxide, zirconium hydroxide and aluminum hydroxide groups on the surface thereof.
Modified carbon blacks are also contemplated as carbon blacks containing at least one of allyl and vinyl groups on the surface thereof Representative allyl groups are, for example, methyl allyl and propyl allyl groups. Re
Agostini Giorgio
Edme Materne Thierry Florent
Cain Ed
The Goodyear Tire & Rubber Company
Wyrozebski Katarzyna
Young, Jr. Henry C.
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