Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-02-14
2002-10-15
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S326700, C525S326900, C525S327300, C525S328200, C525S328400, C525S328500, C525S328800, C525S329700, C525S342000
Reexamination Certificate
active
06465579
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a silica-polymer composite, more particularly relates to a silica-polymer composite with a low viscosity during mixing with rubber, a good processability, and superior dispersibility. Further, the present invention relates to a rubber composition containing that silica-polymer composite.
A rubber composition comprised of an amino group-containing diene-based rubber and silica is known from Japanese Unexamined Patent Publication (Kokai) No. 64-22940, WP96/30444, Japanese Unexamined Patent Publication (Kokai) No. 9-151275, and Japanese Unexamined Patent Publication (Kokai) No. 9-151276, etc. Further, the method of producing a master batch by coprecipitating a silicate and latex is known from Japanese Patent No. 1146028. Further, the method of producing a rubber-silica reinforced master batch using a silane coupling agent is disclosed in Japanese Unexamined Patent Publication (Kokai) No. 10-231381. Further, U.S. Pat. No. 3,098,837 discloses a composite of butadiene-2-methyl-5 vinyl pyridine copolymer and silica. For the method of synthesis, however, it is indicated that careful control of the pH is required and that control of the drying temperature is also required.
Further, U.S. Pat. No. 4,481,328 discloses a composite of a butadiene-methacrylate copolymer and carbon black.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a silica-polymer composite which coagulates without separation of the silica and polymer by reacting the silica with a specific polymer having a polar ring and benzene ring or a specific polymer having a specific carboxylic acid.
Another object of the present invention is to provide a rubber composition comprised of a blend of this composite and a rubber and having a good processability and superior uniform dispersibility of the silica.
According to a first aspect of the present invention, there is provided a silica-polymer composite obtained by reacting a polymer having a polar group containing a hetero atom and a benzene ring with silica in a solution.
Preferably, the silica is treated with the polymer having the pyridine ring and benzene ring in the molecule in a solution and then treated by another polymer solution.
According to a second aspect of the present invention, there is provided a rubber composition containing such a silica-polymer composite.
Further, according to a third aspect of the present invention, there is provided a method of producing a silica-polymer composite comprising reacting a polymer having a polar group containing a hetero atom and a benzene ring with silica in a solution.
According to a fourth aspect of the present invention, there is provided a silica-polymer composite obtained by reacting a polymer having a carboxylic acid with silica.
According to a fifth aspect of the present invention, there is provided a rubber composition containing such a silica polymer composite.
According to a sixth aspect of the present invention, there is provided a method of producing a silica-polymer composite comprising reacting a polymer having a carboxylic acid with silica.
DETAILED DESCRIPTION
Silica exhibits good viscoelastic characteristics in combination with rubber, but is inferior in dispersibility. It is known to improve the dispersibility of silica using various methods so as to further improve the viscoelastic characteristics. On the other hand, emulsion-polymerized SBR is more advantageous in cost than solution-polymerized SBR and further has the advantage of being superior in dynamic properties. Therefore, the present inventors etc. experimented with using emulsion polymerized SBR to make a master batch, whereupon they discovered that by treating the silica with one of the types of polymers used in the present invention, especially, a vinyl pyridine-containing SBR latex, it was possible to synthesize a composite free from separation of the silica and rubber without control of the pH or control of the drying temperature. This is believed to be due to the aggregation force between benzene rings. Further, the present inventors discovered that it is possible to synthesize a composite free from separation of the silica and rubber even when adding a SBR latex and causing coagulation after adding the vinyl pyridine-containing SBR latex to the silica. Further, since the obtained composite is low in viscosity during kneading with rubber, excellent in processability, and superior in dispersibility as well, it is extremely useful as a master batch for blending of reinforcing silica in rubber compositions.
Further, the inventors discovered that by similarly treating silica by a carboxylic acid-containing latex, it is possible to synthesize a composite without separation of the silica and rubber. Further, they discovered that a surfactant could be used and that colloidal silica could be effectively used as the silica. Further, they discovered that the composite obtained was excellent in processability and superior in dispersibility and a rubber composition containing this was high in tensile strength.
In the present invention, as the polymer having a polar group containing a hetero atom and a benzene group to be reacted with the silica in a solution, typically a diene-based rubber latex having a polar group containing a hetero atom and a benzene ring is used. In the present invention, it is effective if a diene-based rubber latex having a polar group containing a hetero atom and a benzene ring or that diene-based rubber latex having a polar group and a benzene ring and another diene-based rubber latex are used together, since a rubber composition is obtained which has a high degree of balance in the heat buildup, tensile strength, abrasion resistance, processability, and other characteristics.
As he hetero atom, atoms belonging to Group 5B and Group 6B of the second to fourth Periods of the Periodic Table are shown. Specifically, for example, a nitrogen atom, oxygen atom, sulfur atom, phosphorus atom, etc. may be mentioned. Among these, a nitrogen atom, oxygen atom, etc. are preferred.
As he polar group containing such a hetero atom, for example, a hydroxyl group, alkoxysilyl group, epoxy group, carboxyl group, carbonyl group, oxycarbonyl group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, imino group, amino group, nitrile group, ammonium group, imide group, amide group, hydrazo group, azo group, diazo group, oxygen-containing heterocyclic group, nitrogen-containing heterocyclic group, sulfur-containing heterocyclic group, etc. may be mentioned. Among these, a hydroxyl group, carboxyl group, epoxy group, sulfide group, sulfonyl group, amino group, nitrogen-containing heterocyclic group, alkoxysilyl group, etc. are preferred. A hydroxyl group, amino group, carboxy group, nitrogen-containing heterocyclic group, alkoxysilyl group, etc. are more preferred. A carboxyl group, amino group, nitrogen-containing heterocyclic group, alkoxysilyl group, etc. are most preferred.
As the polymer having a polar group containing a hetero tom and a benzene group, for example, (1) a polar group-containing diene-based rubber, such as a copolymer of a vinyl-based monomer having a polar group containing a hetero atom, a conjugate diene, and an aromatic vinyl compound or (2) a diene-based rubber containing a polar group comprising a copolymer of a conjugate diene and an aromatic vinyl compound, wherein the (co)polymer having an active metal bonded in the molecule is reacted with a modifying agent to introduce a polar group containing a hetero atom into the (co)polymer.
The content of the monomers in the diene-based rubber containing a polar group obtained by copolymerization of (1) as stated above may be suitably selected in accordance with the objective. In the case of a polymer (rubber) of a vinyl-based monomer having a polar group containing a hetero atom, a conjugate diene, and an aromatic vinyl compound, the content of the bonding units:of the polar group-containing vinyl-based monomer is normally 0.01 to 20 wt %, preferably 0.05 to 15 wt %, m
Chino Keisuke
Onoi Hidekazu
Yatsuyanagi Fumito
Arent Fox Kintner Plotkin & Kahn
Lipman Bernard
The Yokohama Rubber Co. Ltd.
LandOfFree
Silica-polymer composite, method of production thereof, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silica-polymer composite, method of production thereof, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silica-polymer composite, method of production thereof, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2998174