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
2000-12-15
2003-10-21
Wu, David W. (Department: 1713)
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...
C524S225000, C524S261000, C524S265000, C524S269000, C524S280000, C524S282000, C524S418000, C523S213000
Reexamination Certificate
active
06635700
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the preparation and processing of mineral-filled elastomers. More particularly, the present invention relates to a process for the preparation of elastomer compositions comprising inorganic fillers, latent mercaptosilane coupling agents, mercaptosilane coupling agents, latent-mercaptosilane activators, and organic polymers containing carbon—carbon double bonds.
2. Description of Related Art
In the preparation of mineral-filled elastomer compositions, it is known to use as the coupling agent a polysulfide silane in which two alkoxysilyl groups are bound, each to one end of a chain of sulfur atoms. These coupling agents function by chemically bonding silica or other mineral fillers to the polymer when used in rubber applications in a relatively simple and straightforward manner. Coupling is accomplished by chemical bond formation between the silane sulfur and the polymer and by hydrolysis of the silane alkoxy groups, followed by condensation with silica hydroxyl groups.
WO 98/53004 discloses that polysulfide silanes can be used as part of a mineral-treatment process and that these fillers can then be used to prepare rubber masterbatches that are, or can subsequently be, converted to mineral-filled rubber.
Canadian 2231302 A1 also describes the preparation of mineral-filled elastomers containing polysulfide silanes.
U.S. Pat. No. 3,957,718 discloses silica containing mixtures for the improvement of the adhesion of vulcanizable mixtures of natural and/or synthetic rubber to reinforcing fillers or supports of textile and/or metallic fabrics after the vulcanization are prepared that substantially consist of (A) active synthetically produced silica or silicates having a specific surface area according to the BET procedure of about 50 to 500 m
2
/g and an average primary particle size of from about 5 to 100 and at least one of (B) phenolic resin or aminoplast forming components, namely on the one hand phenols and/or amines and on the other hand aldehydes or aldehyde donors, and/or at least (C) one organosilane which can be a bisalkoxysilylalkyl-oligosulfide of a specified formula.
U.S. Pat. No. 4,184,998 discloses the bonding of rubber or other plastics to mineral reinforcements, such as silica pigment. The bonding is brought about by a mercapto alkyl silane without production of foul odors from the mercapto compound by preliminary reversible coupling of the mercapto compound with a material capable of addition reaction, such as toluene diisocyanate. However, the reversible decomposition of the addition product generates toxic isocyanates and poses a health risk to people.
U.S. Pat. No. 4,519,430 discloses a pneumatic radial tire with a tread having from one part by weight of hydrated amorphous fine-particle silica per three parts of carbon black tread reinforcing filler, to about three parts by weight of the silica to one part of the carbon black. The amount of silica present is preferably in the range from about 18 parts to about 50 parts by weight per 100 parts of natural or synthetic rubber. When such a tread is compounded with a mercaptosilane in which the mercapto group is reversibly blocked, the tread is said to provide reduced rolling resistance without loss of traction.
U.S. Pat. No. 4,820,751 discloses a rubber composition for tires said to have improved heat build-up and high temperature reinforcibility that comprises specified amounts of particular surface-treated carbon black, silica and particular silane coupling agent based on 100 parts by weight of the rubber ingredient. The preparation of compositions with these silanes, however, is not desirable because the &agr;-&bgr;-unsaturated carbonyl group of the thioester has the undesirable potential to polymerize during the compounding process or during storage.
U.S. Pat. No. 5,227,425 discloses a sulfur-vulcanizable rubber composition obtained by thermomechanical working of a conjugated diene compound and an aromatic vinyl compound prepared by solution polymerization in a hydrocarbon solvent having a total content of aromatic vinyl compound of between 5% and 50% and a glass transition temperature (Tg) of between 0° C. and −80° C. with 30 to 150 parts by weight per 100 parts by weight of elastomer of a silica having a BET surface area of between 100 and 250 m
2
/g, a CTAB surface area of between 100 and 250 m
2
/g, an oil absorption measured in DBP of between 150 and 250 mL/100 g, and an average projected area of the aggregates greater than 8500 nm
2
before use and between 7000 and 8400 nm
2
after thermomechanical mixing as well as the additives conventionally employed, with the exception of the sulfur vulcanization system, comprising at least one heat step reaching a temperature of between 130° C. and 180° C. for a suitable period of time of between 10 seconds and 20 minutes that is a function of the temperature selected in order to carry out the mechanical work and of the nature and volume of the components subjected to the mechanical work, followed by a finishing step consisting of the incorporating of the vulcanization system by mechanical work at a temperature below the vulcanization temperature.
U.S. Pat. No. 5,650,457 discloses rubber mixtures containing at least one rubber, a vulcanizing agent, a filler, optionally other rubber additives and at least one reinforcing additive of a specified formula, which are used for the production of vulcanized rubbers, from which in particular tires can be produced said to have a low rolling resistance combined with a good wet skid resistance and a high abrasion resistance.
U.S. Pat. No. 5,679,728 discloses a rubber composition containing a cross-linkable rubber component and a carbon black having silica adhered to the surface thereof and a silica surface-treated carbon black suitable for use in tire tread where the surface-treated carbon black has a nitrogen specific surface area of 20 to 300 m
2
/g, a ratio of the adsorption amount of iodine and the adsorption amount of iodine after treatment by hydrogen fluoride of at least 0.30 but less than 1.0, and a ratio of the adsorption amount of iodine after extraction from a rubber compound and the value of the same after treatment by hydrogen fluoride of at least 0.30 but less than 1.0.
U.S. Pat. No. 6,127,468 discloses the use of blocked mercaptosilanes in filled polymers, wherein the hydrogen atom of the mercaptan functionality has been substituted. The blocked mercaptosilanes described are unique in that they allow the mixing of fillers with organic polymers to proceed with surpressed reactivity toward coupling to the polymer. The coupling reactions of these blocked mercaptosilane compounds are triggered subsequently by addition of an appropriate deblocking agent, which preferably is tetramethylthiuram monosulfide.
JP 63270751 A2 discloses the preparation of rubber compositions for use in tire treads, using silane coupling agents represented by the general formula, CH
2
═C(CH
3
)C(═O)S(CH
2
)
1-6
Si(OCH
3
)
3
. The preparation of compositions with these silanes, however, is not desirable because the unsaturation adjacent to the carbonyl group of the thioester has the undesirable potential to polymerize during the compounding process or during storage.
AU-A-10082/97 discloses the preparation of rubber compounds using silanes of the structure represented by R
1
n
X
3-n
Si—(Alk)
m
(Ar)
p
—S(C═O)—R (Formula 1) where R
1
is phenyl or alkyl; X is halogen, alkoxy, cycloalkoxy, acyloxy, or OH; Alk is alkyl; Ar is aryl; R is alkyl, alkenyl, or aryl; n is 0 to 2; and m and p are each 0 or 1, but not both zero. Compositions of the structure of Formula 1 must be used in conjunction with functionalized siloxanes.
U.S. Pat. No. 3,922,436 discloses carboxylic acid functional silances that are used as coupling agents in glass fiber reinforced elastomers. The silanes are formed by the reaction of an epoxy, a mercapto or an amino silane with a carboxylic acid or anhydride.
Other known means for the preparation of mineral-filled elastomers m
Cruse Richard W.
Hannon Martin J.
Joshi Prashant G.
Osterholtz Frederick D.
Pickwell Robert J.
Crompton Corporation
Dilworth Michael P.
Hu Henry S.
Wu David W.
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