Showing papers on "Styrene-butadiene published in 1983"

Process for magnetic image character recognition

Abstract: Disclosed is an improved, simple, economical process for generating documents, such as personal checks, suitable for magnetic image character recognition, which process comprises generating such documents with conventional xerographic methods in a high speed electronic laser printing device, and wherein there is selected as the developer composition a magnetic toner containing from about 20 percent by weight to about 70 percent by weight of magnetite particles, and from about 30 percent by weight to about 80 percent by weight of toner resin particles of styrene copolymers, such as a styrene butadiene copolymer, a styrene n-butylmethacrylate copolymer, or polyesters, and wherein the carrier particles are comprised of ferrite cores, coated with various polymeric resinous compositions. There can also be included in the developer composition various additives such as collodial silica particles, and charge enhancing additives, and further conductive carbon black or insulating carbon black particles can be incorporated into the carrier polymeric resinous coating.

Scanning electron microscopy studies on mechanism of tear fracture of styrene-butadiene rubber

Abstract: Scanning electron microscopy (SEM) studies on tear fracture of styrene-buatadiene rubber (SBR) vulcanizates have been made with respect to the following parameters: (a) the nature of cross-links (flexible sulphur (-Sx-) type and rigid carbon-carbon (-C-C-) type); (b) the effect of addition of reinforcing filler, ISAF carbon black (N 220) in both cross-linking systems; and (c) the effect of cross-link density in the case of sulphur-cured vulcanizates. It was observed that peroxide-cured SBR (unfilled) vulcanizate undergoes brittle fracture whereas the optimum cross-linked sulphur-cured unfilled vulcanizate undergoes fracture in the shear planes and with branching of the tear path. In the case of sulphur-cured SBR (unfilled) vulcanizate with a higher cross-link density the fracture pattern is similar to that of the vulcanizate which has an optimum cross-link density. When the cross-link density is increased or the nature of cross-link is changed to the rigid C-C type, stress dissipation becomes difficult and hence the tear resistance decreases. Peroxide-cured SBR (filled) vulcanizate shows a typical stick-slip mode of fracture as well as steady tear and microfolds over the surface. Sulphur-cured SBR (filled) vulcanizates show short and curved tear lines. Fillers help to arrest crack growth and to increase stress dissipation, thereby increasing tear resistance.

Styrene butadiene plasticizer toner composition blends

Abstract: This invention is directed to an improved positively charged toner composition comprised of (1) a styrene butadiene copolymer plasticizer blend, containing from about 92 percent by weight to about 97 percent by weight of styrene butadiene copolymer, and from about 3 percent by weight to about 8 percent by weight of plasticizer, the styrene butadiene copolymer having a weight average molecular weight of from about 45,000 to about 155,000, and a molecular weight distribution of about 7, the copolymer further containing from about 85 percent by weight of styrene to about 93 percent by weight of styrene, and from about 7 percent by weight of butadiene to about 15 percent by weight of butadiene, (2) pigment particles, and (3) a charge enhancing additive.

Production of styrene-butadiene copolymer

Abstract: PURPOSE: To obtain a styrene-butadiene copolymer of improved resilience and heat build-up resistance, by copolymerizing styrene with butadiene in the presence of a Lewis base under a specified condition and adding a polyfunctional coupling agent to the product. CONSTITUTION: The purpose copolymer is obtained by adding a Lewis base to a polymerization system in which styrene is copolymerized with butadiene in a hydrocarbon solvent by using an organolithium compound as a polymerization initiator; initiating the copolymerization of the styrene with a portion of the butadiene to be added; continuously or intermittently adding the remaining portion of the butadiene to be added, in such a way that the styrene monomer content of the monomer component in the polymerization system is always maintained at a value which is at most twice the bound styrene content of the copolymer finally produced till the conversion to the polymer reaches 98wt%; and adding a polyfunctional coupling agent after completion of the copolymerization. COPYRIGHT: (C)1984,JPO&Japio

Vitamin e/dltdp stabilizer system for chewing gum sbr

Abstract: Styrene butadiene rubber (SBR) is widely used as a chewing gum base in lieu of natural gums. It is necessary to protect chewing gum SBR with a food grade antioxidant stabilizer system. This invention discloses a chewing gum rubber composition (gum base) that utilizes as an antioxidant stabilizer system a combination of dilauryl thiodipropionate and at least one member selected from the group consisting of t-butyl-hydroquinone (TBHQ), and Vitamin E.

Branched styrene-butadiene copolymers and pneumatic tires using the same

Abstract: A branched styrene-butadiene copolymer and a pneumatic tire using the same as a tread base rubber are disclosed. This copolymer is produced by coupling an active styrene-butadiene copolymer anion, which is obtained by polymerizing styrene and butadiene in a hydrocarbon solvent in the presence of ether or a tertiary amine and an initiator of an organolithium compound, with a tin halide compound. In the copolymer, the ratio of branched copolymer connected with tin-butadienyl bond is at least 20% by weight, and the content of bound styrene is not less than 3% by weight but less than 25% by weight, and the content of vinyl bond in butadiene portion is not less than 30% but less than 50%.

Char resistant foams

Abstract: "CHAR RESISTANT FOAMS" Abstract of the Disclosure The resistance to internal charring of molded styrene butadiene latex foam rubber when exposed to a lit cigarette is improved by the addition of certain organic phosphates or butyl benzyl phthalate.

Sequence distribution of styrene-butadiene copolymer initiated by n-butyllithium

Abstract: Copolymerisation effectuee dans le toluene. Chromatographie sur gel des produits d'ozonolyse par rapport a la relation temps-conversion et temps-composition du copolymere

Statistical mechanical theory of deformation of liquid crystalline structure in styrene-butadiene diblock copolymers in n-tetradecane

Abstract: Le tetradecane est un bon solvant pour les sequences butadienes mous un non-solvant pour les sequences styrene. Relation entre la temperature et la rigidite du reseau

Transient decay studies of photophysical processes in aromatic polymers. 7. Studies of the molecular weight dependence of intramolecular excimer formation in polystyrene and styrene-butadiene block copolymers

Abstract: La cinetique de la fluorescence ne peut pas etre attribuee a l'existence d'especes monomeres cinetiquement distinctes

Colloidal Structure-Property Relationships in Carboxylated Styrene-Butadiene Latexes

Abstract: 1. The hydrodynamic particle size of the latexes, measured by light transmission and liquid exclusion chromatography, was, in general, higher than the dry particle size measured by electron microscopy. At comparable high pH and acid level, a methacrylic latex swelled more than an itaconic latex, indicating difference in acid incorporation. 2. Carboxylic acid incorporation in batch-polymerized SB latexes containing itaconic and/or methacrylic acid was strongly influenced by the level and relative ratio of the two acid monomers in the recipe. Itaconic acid distributed primarily between the surface and the serum and none in the bulk polymer. Methacrylic acid distributed primarily between the surface and the bulk of the polymer and none in the serum. The acid distribution results can, in general, be understood in terms of the relative solubilities of the acid monomers in water and styrene. 3. It appeared that the percentage of the total acid bound to the surface could be maximized by the use of certa...

Metallized article composed of polyphenylene ether resin, high impact polystyrene, alumina and, optionally, a styrene-butadiene radial teleblock copolymer

Abstract: The adhesion of metal deposited from a metal deposition bath on the surface of an article molded from a thermoplastic composition of a polyphenylene ether resin is considerably improved by including alumina in the substrate composition, as described. The resultant parts, in stressed and unstressed form, exhibit bond strengths of at least 0.7 Kg/cm, initially and after aging for several days, and are much more likely to withstand conditions normally causing separation of the metal deposit from the substrate.

Effect of sulfur on the electrical conductivity of FEF‐loaded SBR during swelling

Abstract: Following a series of experiments on the effect of different factors of the electrical conductivity of carbon-black-loaded styrene butadiene rubber, an attempt was made to study the effect on electrical conduction of changing the sulfur content. It was found that an optimum sulfur content leads to a swelling-resistant composite with good electrical insulation. This was done for dry as well as wet specimens of rubber.

Styrene-butadiene copolymer having wide distribution of molecular weight

Abstract: PURPOSE:The titled copolymer prepared by coupling active styrene-butadiene anions obtained by a special reaction with a tin halide compound, having improved processability, tensile characteristics and impact resilience, etc., and suitable for tire tread rubber. CONSTITUTION:Active styrene-butadiene copolymeric anoins obtained by polymerizing butadiene with styrene in the presence of an ether, e.g. tetrahydrofuran (THF), or tertiary amine and an organolithium compound, e.g. n-butyl lithium, are coupled with a tin halide compound to give the aimed copolymer having 2- 5(Mw/Mn) molecular weight distribution, >=30%, preferably 40-90%, vinyl bond content in the butadiene part, 5-40wt% combined styrene content and >=30wt% branched polymeric content linked through tin-butadienyl bonds.

Biaxially stretched styrene-butadiene copolymer film

Abstract: PURPOSE:To obtain said film of a large stretch ratio and excellent physical properties, by biaxially stretching the styrene-butadiene copolymer of a specified tapered block structure. CONSTITUTION:The tapered block copolymer having a copolymer part which varies gradually its monomer ratio of styrene/butadiene between a styrene block and a butadiene block is formed by polymerizing styrene solely, after that feeding the mixed monomer of styrene and butadiene and continuing polymerization [(provided, a molecular weight distribution (a weight average molecular weight/ a number average molecular weight) >=2)]. Then, the film of a dart impact strength more than 600g.cm is formed by biaxially stretching this.

Radial tire for passenger vehicle

Abstract: PURPOSE:To enhance the mobility on a slipable road surface, heating, low fuel consumption of a tire having a two layer structure tread, by tread ratio of the outer surface rubber layer, and as well specifying the post-vulcanization characteristics of the inner surface rubber layer. CONSTITUTION:An outer surface rubber 1 having a tread ratio of 0.5-0.9, a complex elastic modulus 3-8MPa at 70 deg.C and a loss tangent 0.1-0.5, is formed with the use of 10-70pts.wt. of natural rubber and/or synthetic polyisoprene rubber, 10-50pts.wt. of poly butadiene rubber including 5pts.wt. of polybutadiene rubber in which the 1, 2 vinyle coupling content is less than 20wt% and more than one atomic groups having predetermined formulae are coupled to molecular chains, less than 60pts.wt. of styrene butadiene rubber containing 10-30wt% of styrene, 30-80pts.wt. of stretching oil having a viscosity gravity constant of 0.80-0.93, and 60-110 of carbon black. Further, the above-mentioned characteristics values of an inner surface rubber 2 is set at values of 2-7MPa and 0.04- 0.15, respectively.

Process for separating a polymer from a solution containing the same

Abstract: In order to recover a polymer, such as styrene butadiene copolymer rubber, from a solution obtained by a solution polymerization of the corresponding comonomers, without degradation or deterioration of the polymer, the solution, ordinarily in 3 to 30% by weight concentration, is separated into the solvent and a more concentrated polymer solution of not less than 50% by weight, by heating the solution under a pressure at such a temperature (A) that the polymer does not decompose, heating a solvent, which is preferably the same as that for the solution, at a higher temperature than (A) above under a pressure, and joining the heated solution and the heated solvent in a mixer to convey to a flash evaporator.

Mechanical Characterization of Blends of Polystyrene and Styrene-Butadiene-Styrene

Abstract: During the last decade, block copolymers have received considerable interest in both the industrial and research communities because they offer many routes by which other engineering properties besides high strength can be obtained. More notably, the polystyrene (PS) and styrene-butadiene-styrene (SBS) systems have received significant interest in both the adhesive and xerographic business. This paper describes preliminary work directed at exploring the composition dependence of polymer blends in the PS and SBS systems. The thrust area of this research is to identify the major factors governing the “cold flow” properties of these polymers for several compatible blends. Among the many mechanical properties, a modulus reduced yield strength is introduced in an effort to evaluate the intrinsic resistance of the blends to permanent deformation. This present work is concerned with evaluation of the properties of model experimental materials which can be subsequently used in coating applications. Blend...

Bonding method of urethane rubber to general purpose rubber

Abstract: PURPOSE:To improve the interlayer adhesive strength of a double layer rubber board by a method wherein the roughened surface of general purpose rubber is coated with adhesive agent for urethane rubber and unvulcanized urethane rubber is mounted on the coated surface then pressure and hot vulcanization are applied thereon. CONSTITUTION:The surface of general purpose rubber composed of various kinds of synthetic rubber such as natural rubber, styrene butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, etc. is roughened by a grinder or the like. The roughened surface is coated with adhesive agent for urethane rubber composed mainly of disphenyl methane isocyanate, then, unvulcanized urethane is mounted on said coated surface. Then, pressure 10-30kg/cm is applied on to the above-mentioned mounting surface and hot vulcanization is performed at 100-170 deg.C. It is possible to obtain, by this process, an excellent lining material for the roller, chute, etc. that is not separated into two layers.

Branched styrene-butadiene copolymer

Abstract: PURPOSE:The titled copolymer, prepared by coupling active sttyrene-butadiene copolymeric anions obtained by a special reaction with a tin halide compound, having reduced hysteresis loss and rupture characteristics, and suitable for tire rubbers. CONSTITUTION:Active styrene-butadiene copolymeric anions obtained by polymerizing butadiene with styrene in the presesnce of an organolithium compound initiator and an ether or tertiary amine in a hydrocarbon solvent at 0-50 deg.C initial temperature, =30 deg.C difference between the initial and the maximal ultimate temperatures are coupled with a tin halide compound to give the aimed copolymer having >=20wt% branched polymeric content linked to tin-butadienyl bonds, 3-25% combined styrene content and 30-50% content of vinyl bonds in the butadiene part.

Pneumatic radial tire for passenger vehicle

Abstract: PURPOSE:To enhance the external hurt-resistivity of the side surface parts of a pneumatic radial tire having a reinforcing layer including one piece of carcass section, and as well to aim at lowering the hysteresis loss of the carcass section, by specifying the chemical structure, blending and post-vulcanization characteristics. CONSTITUTION:A carcas rubber having a hynamic accumulated elastic modulus in a range including 3MPa and 7MPa and a dynamic loss factor of 0.130 or less than the value is formed such that 5-40pts.wt. of styrene butadiene coplymer in which the styrene content is 10-30wt%, the 1, 2 vinyle coupling is 5 to 40wt% and the content of styrene butadiene coplymer rubber containing more than one predetermined atomic groups coupled by carbon-carbon coupling is 2.5pts.wt. 60-95pts. of natural rubber and/or polyisoprene rubber, 30-35pts.wt. of carbon black having an I2 absorption amount of 50-100mg/m are blended. With this arrangement, the hystersis loss of the carcass section may be lowered while the external hurt-resistivity of the tire is maintained.

Method for reducing hysteresis in synthetic rubber stocks and rubber articles made therefrom

Abstract: A method for reducing hysteresis in synthetic rubber stocks containing carbon black includes the step of mechanically compounding carbon black with a rubber selected from the group consisting of emulsion and solution styrene butadiene rubber and blends of each with and without 1,4-polybutadiene rubber to form a masterbatch containing less than 100 parts of rubber, adding additional parts of the rubber to the masterbatch so the total parts of rubber equals 100 and the amount of carbon black is reduced to an amount less than the level present in the masterbatch and, mechanically compounding the additional rubber with the masterbatch to form a rubber compound. An improved tire having a tread stock possessing improved rolling resistance and skid resistance is also disclosed wherein the tread stock is prepared by the steps of mechanically compounding carbon black with a rubber selected from the group consisting of emulsion and solution styrene butadiene rubber and blends of each with and without 1,4-polybutadiene rubber to form a masterbatch containing less than 100 parts of rubber, adding additional parts of the rubber to the masterbatch so the total parts of rubber equals 100 and the amount of carbon black is reduced to an amount less than the level present in the masterbatch and, mechanically compounding the additional rubber with the masterbatch to form a rubber compound from which the tread stock is prepared.

Production of styrene/butadiene rubber

Abstract: PURPOSE:To obtain a styrene/butadiene rubber excellent in abrasion resistance, wet skid resistance, etc, and suitable for use in tire treads, etc, by polymerizing styrene with butadiene in two stages by an emulsion polymerization process CONSTITUTION:A 1,3-butadiene monomer alone or a 1,3-butadiene/styrene mixed monomer having a 1,3-butadiene monomer content of above 86wt% is polymerized in the presence of a radical initiator by an emulsion polymerization process The purpose styrene/butadiene rubber having an average styrene content of 15- 50wt% is obtained by adding a styrene monomer alone or a styrene/1,3-butadiene monomer mixture to the former stage polymerization step and continuing the polymerization reaction The styrene/butadiene rubber thus obtained has a wide distribution of reacted styrene amount and excellent tire performances

Micellization of styrene/butadiene/styrene block copolymers in mixed solvents

Abstract: Dilute solutions of three block copolymers, styrene/butadiene/styrene in the mixed selective solvents dioxane/different alcohols is studied at different temperatures. The molecular weight, second virial coefficient and radius of gyration in all selective solvents are also determined. From these measurements it is concluded that a maximum in the dissymmetry of the system for all the selective solvents used is observed. This maximum is observed at higher temperatures for concentrated solutions. Similarly, this maximum is also shifted to lower temperature by using strong precipitants in selective solvents. The milky opalescence is observed for all the selective solvents either by lowering the temperature of the system or by increasing the ratio of the precipitant in the selective solvent.