摘要:
Tire rubbers which are prepared by anionic polymerization are frequently coupled with a suitable coupling agent, such as a tin halide, to improve desired properties. It has been unexpectedly found that greatly improved properties for tire rubbers, such as lower hysteresis, can be attained by asymmetrically coupling the rubber. This invention more specifically discloses an asymmetrical tin-coupled rubbery polymer which is particularly valuable for use in manufacturing tire tread compounds, said asymmetrical tin-coupled rubbery polymer being comprised of a tin atom having at least three polydiene arms covalently bonded thereto, wherein at least one of said polydiene arms has a number average molecular weight of less than about 40,000, wherein at least one of said polydiene arms has a number average molecular weight of at least about 80,000, and wherein the ratio of the weight average molecular weight to the number average molecular weight of the asymmetrical tin-coupled rubbery polymer is within the range of about 2 to about 2.5.
摘要:
A method is disclosed for processing a rubber composition comprising thermomechanically mixing at a rubber temperature in a range of 140.degree. C. to 190.degree. C. for a mixing time of 1 to 20 minutes(i) 100 parts by weight of at least one sulfur vulcanizable elastomer selected from conjugated diene homopolymers and copolymers, natural rubber and copolymers of at least one conjugated diene and aromatic vinyl compound;(ii) 10 to 250 phr of particulate precipitated silica;(iii) 0.01 to 1.0 parts by weight per weight of said silica of an organosilicon compound; and(iv) 0.05 to 10 phr of sodium thiosulfate pentahydrate.Addition of the sodium thiosulfate pentahydrate to sulfur vulcanizable rubber, silica and sulfur containing organosilicon compound decreases the mixing/processing time without sacrificing end product properties.
摘要:
Polyurethanes having a fine particle size are prepared according to a suspension process wherein silicone surfactants are utilized and the polymerization is carried out under agitation in a nonaqueous and a nonsolvent system according to either a two step, or preferably a one step process. The produced suspension-type polyurethanes are generally powders or very small granules and, therefore, can be utilized directly for rotational or spin molding processes wherein they are cured through the use of specific curing agents. Additionally, generally any suspension polyurethanes having a plasticity value of at least 2,000 square mm. at 150.degree. C, can be cured in a rotational or spin molding operation utilizing specific curing agents and curing at a temperature below the decomposition temperature of the polyurethane, for example, below 250.degree. C.
摘要:
A polyurethane-urea elastomer is prepared by reacting a copolymer of propylene oxide and tetrahydrofuran having hydroxyl end groups with an organic polyisocyanate and the isocyanate-terminated polymer is then reacted with an aromatic diamine in either bulk or solution process.
摘要:
The process disclosed herein involves the continuous preparation of a multiblock copolymer of two monomers or more such as butadiene and styrene, butadiene and isoprene, etc. This process comprises the alternate feeding of first one monomer stream and then another monomer stream differing in monomer composition from the first monomer stream, each stream of monomer being interrupted while the other stream of monomer is being fed continually into the polymerization system containing an anionic polymerization catalyst capable of polymerizing each of said monomers. A product stream is withdrawn from the polymerization system at the same rate as the total of the feed streams, thereby effecting a continual flow through the polymerization system. The rate of catalyst feed is controlled to give the desired molecular weight to the multiblock copolymer; the size of each block in the copolymer is controlled by the time of flow of the respective monomer and the concentration of monomer in the monomer feed; and the number of blocks is controlled by the number of alternating feed steps that are performed during the residence time in the polymerization system.
摘要:
This invention relates to the preparation of silica-containing rubber compositions which contain precipitated silica reinforcement and use of an oligomeric organomercaptosilane coupling agent containing a plurality of mercapto and silane moieties, and a minimal content, if any, of ethoxy groups and is thus substantially free of ethoxy groups. The interaction of the plurality of mercapto moieties, or groups, of such oligomeric organomercaptosilane with the diene-based elastomer can promote a significant viscosity build up of the uncured rubber composition in a preliminary non-productive mixing stage and therefore present significant rubber processing difficulties during the mixing of the rubber composition. A challenge is therefore presented for reducing such viscosity buildup for such uncured silica-containing rubber composition.
摘要:
Rubbery polymers can be formed having the general formula: R1R2N—(CH2)n—X—CH2—CHR3R4 wherein R1 and R2 are independently selected from a group consisting of alkyls, cycloalkyls, alkenyls, cycloalkenyls, aryls, phenyls, heterocycles, acyls, and silanes, or R1 in combination with R2 forms a heterocyclic ring; n is an integer from 1 to 20; X is selected from a group consisting of sulfur, a phosphorus moiety, and a silicon moiety; R3 and R4 are one of hydrogen, alkyls, alkenyls, and at least one of which includes reactive unsaturation such as an alkenyl group. Moreover, this invention discloses a process of making functionalized rubbery polymers from the functionalized monomers.
摘要:
This invention relates to the preparation of silica-containing rubber compositions which contain precipitated silica reinforcement and use of an oligomeric organomercaptosilane coupling agent containing a plurality of mercapto and silane moieties, and a minimal content, if any, of ethoxy groups and is thus substantially free of ethoxy groups. The interaction of the plurality of mercapto moieties, or groups, of such oligomeric organomercaptosilane with the diene-based elastomer can promote a significant viscosity build up of the uncured rubber composition in a preliminary non-productive mixing stage and therefore present significant rubber processing difficulties during the mixing of the rubber composition. A challenge is therefore presented for reducing such viscosity buildup for such uncured silica-containing rubber composition.
摘要:
This invention relates to a rubber composition which contains a dispersion of a particulate hydrophilic water absorbing polymer and tire with a tread thereof.
摘要:
The invention relates to a tire having a circumferential tread of a cap/base configuration composed of an outer tread rubber cap layer with a running surface of the tread and an underlying tread rubber base layer, wherein said tread cap layer is composed of two longitudinal adjacent zones, namely a primary tread cap zone and a minor lateral outboard control element (zone). The primary tread cap zone and the lateral outboard tread cap element provide a significant gradation of cold dynamic storage moduli (G′) at −25° C. and hot tan delta values at 100° C., yet similar warm dynamic storage moduli (G′) at 60° C. The primary tread cap zone and lateral outboard control tread cap element are load bearing in the sense of extending from the running surface of the tread radially inward to the unitary (non-zoned) tread base rubber layer. The zoned rubber tread cap layer and unitary rubber tread base layer are an integral tread composite in a sense of being co-extruded. In one aspect of the invention, the primary tread cap zone rubber composition is silica-rich and the lateral, outboard element rubber composition is carbon black-rich and which furthermore provide a gradation of filler reinforcement content; provide a gradation of silica to carbon black ratio and provide a gradation of cis 1,4-polybutadiene rubber content.