Abstract: A method for preparing modified calcined kaolin particles with surface amphiphilicity. The method includes the steps of drying and sieving the calcined kaolin particles, adding ethanol, and stirring to obtain a suspension A, preparing an ethanol solution of a vinyl silane coupling agent, and stirring for a period of time at a certain temperature to obtain a solution B, dripping the solution B into the solution A, and stirring for a period of time at a certain temperature to obtain a suspension C, reducing the temperature of the suspension C, introducing nitrogen, adding a certain amount of sulfhydryl compound, stirring for a period of time at a certain temperature to obtain a suspension D, filtering, washing and drying to obtain the modified calcined kaolin particles.

Abstract: An object of the present invention is to provide a diene-based polymer that can control the crosslinking morphology. The present invention provides a modified diene-based polymer having a structure represented by the formula (1). [In the formula (1), R1 and R2 represent an alkyl group having 1 or more carbon atoms, an aryl group having 6 or more carbon atoms, an aralkyl group having 6 or more carbon atoms, a hydrogen atom, or a halogen atom; and Z is an organic group, an organic group where a part of hydrogen atom of the above organic group is substituted, a hydrogen atom, or a halogen atom.

Abstract: Methods of post-polymerization modification of a polymer are provided herein. The present methods comprise the step of reacting a polymer with at least one nucleophile in a nucleophilic substitution reaction performed without a solvent to produce a functionalized polymer. The nucleophile can be selected from the group consisting of thioacetate, phenoxide, alkoxide, carboxylate, thiolate, thiocarboxylate, dithiocarboxylate, thiourea, thiocarbamate, dithiocarbamate, xanthate, thiocyanate. Nucleophilic substitution reaction can be performed in the presence of a phase transfer catalyst. Nucleophilic substitution reaction can also be performed via a two-step in-situ reactive mixing process with the initial formation of the polymer-amine ionomer (polymer-NR3+Br) which catalyzes the subsequent nucleophilic substitution with a second nucleophile to form a bi-functional polymer.

Abstract: This invention relates to coating compositions comprising at least one aminoplast crosslinker resin A, binder resins B that have active hydrogen functionality, and a catalyst composition C, wherein the catalyst composition C is a mixture of an organic sulfonic acid C1, and an amine C2 which may be primary, secondary, or tertiary, and which must have a pKa value of not more than 10, and preferably not less than 4, a process for the preparation thereof, and to a method of use thereof.

Abstract: The invention relates to an antistatic silicone release film having a layer coated with an antistatic silicone release composition, and, used for semiconductors, electronics and display devices while addressing problems of static electricity generated when a general release film is separated from adhesive or an adhesive layer, and of contamination by such static electricity that causes critical product defects. The invention also relates to an antistatic silicon release film that can reduce product contamination caused by static electricity in peeling the film from adhesive or an adhesive layer, and achieves close adhesion between a substrate and a coated layer because of no interruption in curing a release layer, and also thereby has a stable release property.

Abstract: The present invention generally relates to vulcanization compositions used to vulcanize elastomeric articles, where the vulcanization compositions have reduced allergenic potential as compared to elastomeric articles formed using vulcanization compositions having non-fugitive accelerators. The present invention also relates to elastomeric articles formed using the vulcanization compositions. The invention further relates to methods for making a reduced-allergenicity vulcanization composition, and to methods for using the vulcanization compositions to vulcanize elastomeric articles.

Abstract: The present invention relates to the use of a silicon containing compound for reducing the retention time of a polyolefin composition comprising a crosslinkable polyolefin with hydrolysable silane groups. A master batch is compounded with the polyolefin composition to form a compounding composition. The master batch comprises a matrix polymer, a Bronsted acid that is a silanol condensation catalyst and is present in the amount of 0.7 to 3.5 wt %, and a silicon containing compound with a structure according to the formula (I): (R1)x[Si(R2)y(R3)z]m wherein R1 is C6-22 alkyl, R2 is C1-10 alkoxy, R3 is —R4SiR1R2 , R4 is —(CH2)rYs(CH2)t— where Y is a difunctional heteroatomic group, x+y+z=4, and m=1. The silicon containing compound is 2 to 10 wt % of the master batch, and 0.01 to 1.5 wt % of the compounding composition.

Abstract: A method for preparing a functionalized polymer, the method comprising the steps of (i) polymerizing monomer with a coordination catalyst to form a reactive polymer; and (ii) reacting the reactive polymer with a carboxylic or thiocarboxylic ester containing a silylated amino group.

Abstract: Provided are a sulfur-modified chloroprene rubber with reduced exothermicity, a molding thereof, and a production method therefor. A sulfur-modified chloroprene rubber modified at the polymer terminals with at least one compound selected from tetramethylthiuram disulfide, tetraalkylthiuram disulfides with alkyl groups having a carbon number of 2 to 7 and dialkyldithiocarbamic acid salts with alkyl groups having a carbon number of 1 to 7, wherein there are peak tops at 3.55 to 3.61 ppm and at 3.41 to 3.47 ppm in 1H-NMR spectrum, as determined in deuterochloroform solvent, wherein the ratio (A/B) of the peak area (A) at 3.55 to 3.61 ppm to the peak area (B) at 4.2 to 6.5 ppm is 0.05/100 to 0.50/100, and the extract with ethanol/toluene azeotropic mixture, as specified by JIS K 6229, is 3.0 to 9.0 mass %.

Abstract: Provided herein are telechelic polymers and methods for producing the same. In some embodiments, provided herein are compounds having the formula and methods for producing the same.

Abstract: Disclosed are a conjugated diene-based polymer from which a polymer composition excellent in fuel cost-saving properties and a tensile strength at break can be obtained. There is provided a conjugated diene-based polymer having a monomer unit based on a conjugated diene, a monomer unit based on a compound represented by the following formula (1), and a monomer unit based on a compound represented by the following formula (2), in which at least one end of the polymer is modified with the following compound (G). V1-S1??(1) wherein V1 represents a hydrocarbyl group having a polymerizable carbon-carbon double bond, and S1 represents a substituted silyl group.) V2-A2??(2) wherein V2 represents a hydrocarbyl group having a polymerizable carbon-carbon double bond, and A2 represents a substituted amino group, or a nitrogen-containing heterocyclic group.

Abstract: The present invention provides: a rubber composition for a tire having favorable productivity, excellent heat aging resistance and abrasion resistance, and excellent fuel economy; and a pneumatic tire using the rubber composition. The rubber composition contains neither soluble sulfur nor insoluble sulfur, and contains diene rubber, 1-15 parts by mass of compound 1 represented by formula (1) and 0.1-5 parts by mass of compound 2 represented by formula (2), per 100 parts by mass of the diene rubber, and the amount ratio of compound 1 to compound 2 (compound 1/compound 2) is 1-8. wherein R1-R4 are the same or different, and represent C1-20 alkyl, C6-20 aryl, or C7-20 aralkyl, and n represents an integer of 1-12; wherein R5-R7 are the same or different, and represent C5-12 alkyl, x and y are the same or different, and represent an integer of 2-4, and m represents an integer of 0-10.

Abstract: Disclosed are a conjugated diene-based polymer from which a polymer composition excellent in fuel cost-saving properties and a tensile strength at break can be obtained. There is provided a conjugated diene-based polymer having a monomer unit based on a conjugated diene, a monomer unit based on a compound represented by the following formula (1), and a monomer unit based on a compound represented by the following formula (2), in which at least one end of the polymer is modified with the following compound (G). V1-S1??(1) wherein V1 represents a hydrocarbyl group having a polymerizable carbon-carbon double bond, and S1 represents a substituted silyl group.) V2-A2??(2) wherein V2 represents a hydrocarbyl group having a polymerizable carbon-carbon double bond, and A2 represents a substituted amino group, or a nitrogen-containing heterocyclic group.

Abstract: The present invention provides a modified conjugated diene polymer that is prepared by polymerization of a conjugated diene compound using a catalyst containing a lanthanoid rare earth element compound in an organic solvent and then modifying the resulting polymer having an active organic metal site with a modifier, wherein the modification efficiency is not less than 15% and the cis-1,4 bond content in the conjugated diene moiety measured by Fourier transform infrared spectroscopy satisfies the relationship (I): cis-1,4 bond content?98.00(%)??(I), or the modification efficiency is not less than 75% and the cis-1,4 bond content in the conjugated diene moiety measured by Fourier transform infrared spectroscopy satisfies the relationship (II): 94.00(%)?cis-1,4 bond content<98.00(%)??(II).

Abstract: The present invention provides: a rubber composition for a tire having favorable productivity, excellent heat aging resistance and abrasion resistance, and excellent fuel economy; and a pneumatic tire using the rubber composition. The rubber composition contains neither soluble sulfur nor insoluble sulfur, and contains diene rubber, 1-15 parts by mass of compound 1 represented by formula (1) and 0.1-5 parts by mass of compound 2 represented by formula (2), per 100 parts by mass of the diene rubber, and the amount ratio of compound 1 to compound 2 (compound 1/compound 2) is 1-8. wherein R1-R4 are the same or different, and represent C1-20 alkyl, C6-20 aryl, or C7-20 aralkyl, and n represents an integer of 1-12; wherein R5-R7 are the same or different, and represent C5-12 alkyl, x and y are the same or different, and represent an integer of 2-4, and m represents an integer of 0-10.

Abstract: A seal for a valve for use in a pharmaceutical dispensing device, which seal is formed from an elastomeric composition comprising: (a) an isobutylene polymer or co-polymer thereof; (b) a cross-linking agent for the isobutylene polymer or co-polymer thereof; and (c)) an accelerator for the cross-linking agent, wherein the accelerator includes a polysulphide compound derived from a substituted dithiocarbonic acid or derivative thereof.

Abstract: A thiocarbamoyldisulfanyl-functional cycloaliphatic compound, useful as a crosslinker for filled sulfur-vulcanizable elastomer compositions, is represented by the general formula: G[-CaH2a—S—S—C(?S)NR2]n wherein G is a saturated, monocyclic aliphatic group of valence n containing from 5 to 12 carbon atoms and optionally containing at least one halogen or a saturated monocyclic silicone [RSiO—]n[R2SiO—]p group of valence n; each R independently is a hydrogen or a monovalent hydrocarbon of up to 20 carbon atoms; each occurrence of subscripts a independently is an integer wherein a is 2 to 6; n is an integer of from 3 to 6; and, p is an integer of from 0 to 3.

Abstract: Provided is a curable fluoropolymer composition comprising a fluoropolymer comprising interpolymerized units of tetrafluoroethylene, perfluoro(aliphatic vinyl)ether, and a nitrogen-containing cure site monomer; a catalyst to form cross-links with the nitrogen-containing cure site monomer; an organic peroxide; a co-agent to participate in a peroxide cure; and a hydrotalcite compound. Also provided is an article comprising the cured fluoropolymer reaction product of the curable composition and a method for forming a shaped article.

Abstract: A method for preparing a functionalized polymer, the method comprising the steps of (i) polymerizing conjugated diene monomer by employing a lanthanide-based catalyst to form a reactive polymer, and (ii) reacting the reactive polymer with a protected oxime compound.

Abstract: The present invention includes elastomeric compositions of BIMS elastomers suitable for abrasion resistant, high traction and/or air barrier articles. The compositions and articles made from those compositions of the invention can be described in any number of embodiments. In one embodiment, the composition suitable for an abrasion resistant article includes from 5 to 100 phr of a terpolymer of C4 to C7 isoolefin derived units, p-alkylstyrene derived units and p-bromomethylstyrene derived units; at least one filler such as carbon black, silica, precipitated silica, clay, or combinations thereof, and from 0.1 to 3 phr of at least one thiourea. The composition can also include from 5 to 80 phr of at least one elastomer selected from natural rubbers, polyisoprene rubber, styrene butadiene rubber (SBR), polybutadiene rubber, isoprene butadiene rubber (IBR), styrene-isoprene-butadiene rubber (SIBR), butyl rubber, halogenated butyl rubber, butadiene-acrylonitrile-styrene rubber (SNBR), and mixtures thereof.

Abstract: The present invention includes elastomeric compositions of BIMS elastomers suitable for abrasion resistant, high traction and/or barrier articles. The compositions and articles made from those compositions of the inventions can be described in any number of embodiments. In one embodiment, the composition suitable for an abrasion resistant article includes from 5 to 100 phr of a terpolymer of C4 to C7 isoolefin derived units, p-alkylstyrene derived units and p-bromomehtylstyrene derived units; at least one filler such as carbon black, silica, precipitated silica, clay, or combinations thereof; and from 0.1 to 3 phr of at least one thiourea.

Abstract: The present invention includes a composition comprising a coupled impact propylene copolymer. Preferably, the coupled impact propylene copolymer has an elastomeric phase that is present in an amount of at least 9 weight percent of the coupled propylene copolymer. Articles formed from the coupled propylene copolymer exhibit improved directionally balanced impact properties as compared with articles formed form comparable noncoupled impact propylene copolymers and also exhibit improved ductile-to-brittle transition temperatures compared with comparable noncoupled impact propylene copolymers. The invention also includes methods for making the coupled impact propylene copolymers using coupling agents, preferably, poly(sulfonyl azides). The invention further includes articles of manufacture that are made from the coupled impact propylene copolymer of the invention.

Abstract: Transport reagents and conjugates of therapeutic agents linked to transport reagents are described. In particular, the transport reagents have a plurality of guanidinium moieties that are either contiguous or spaced along a backbone, but are sufficiently removed from the backbone via tethers, to allow their interaction with a cell or tissue surface, leading to uptake of the therapeutic agent.

Abstract: A process is provided for the removal of iron- and rhodium-containing residues from a solution of hydrogenated nitrile rubber. The process utilizes an ion-exchange resin having thiourea functional groups. Further, the resin is both macroporour and monodispersed. The process removes both rhodium and iron from viscous rubber solutions. In a preferred embodiment, the process is carried out in an ion-exchange column.

Abstract: Transport reagents and conjugates of therapeutic agents linked to transport reagents are described. In particular, the transport reagents have a plurality of guanidinium moieties that are either contiguous or spaced along a backbone, but are sufficiently removed from the backbone via tethers, to allow their interaction with a cell or tissue surface, leading to uptake of the therapeutic agent.

Abstract: A sulfur vulcanizing system rubber composition comprises EPDM, zinc as a vulcanization accelerator activator, at least one thiazole type vulcanization accelerator serving to control the dissolution of zinc from the composition, and at least one ultra-accelerator of the thiuram or dithiocarbamate type, these accelerators being preferably combined under specified quantitative limitations. The hose using this rubber composition is particularly suitable for use in a cooling system for an automobile engine, since the dissolution of zinc into a coolant is prevented, thereby preventing the formation of any zinc compound causing the blocking of the hose, or the leakage of the coolant through the seal between the hose and any pipe connected therewith.

Abstract: Sulfur free, crosslinking, scorch-retarding compositions for compounding and cure of polymers susceptible to cure by free radical initiators are disclosed.

Abstract: Polymers coupled by reaction with coupling agents according to the practice of the invention advantageously have at least one of these desirable properties and preferably have desirable combinations of these properties. The present invention includes a process of preparing a coupled polymer comprising heating an admixture containing (1) at least one elastomer comprising ethylene and at least one comonomer which is selected from alpha olefins having at least 3 carbon atoms, dienes and combinations thereof and (2) a coupling amount at least one poly(sulfonyl azide) to at least the decomposition temperature of the poly(sulfonyl azide) for a period sufficient for decomposition of at least about 80 weight percent of the poly(sulfonyl azide) and sufficient to result in a coupled polymer having a gel content of less than about 2 weight percent.

Abstract: The present invention relates to a process for preparing novel, monodisperse crosslinked bead polymers having thiourea groups and their use for adsorbing metal compounds, in particular heavy metal compounds or noble metal compounds.

Abstract: Sulfanylsilanes of the formula X1X2X3Si—A—S—SiR1R2R3 are prepared by reacting mercaptosilanes of the formula X1X2X3Si—Alkyl—SH with chlorosilanes Cl—SiR1R2R3. They are used as coupling agents in rubber mixtures.

Abstract: A vulcanizable dip-forming rubber latex composition comprising an unsaturated nitrile-conjugated diene copolymer rubber latex, a sulfur-containing vulcanizer, and a vulcanization accelerator comprising at least one compound selected from (i) dithiocarbamic acid compounds of the formula: and (ii) zinc dithiocarbamate compounds of the formula: wherein R1 and R2 are hydrocarbon groups having at least 6 carbon atoms which may be the same or different, and an optional thiazole compound. A rubber article dip-formed from the rubber latex composition has no crack occurrence, good surface luster and good vulcanization properties, and does not contain a nitrosamine, and therefore, is suitable for medical use.

Abstract: A polystyrene resin which is substituted in skeletal benzene rings thereof by a group of formula--CH.sub.2 --O--Ar.sup.1 --R Iwhere Ar.sup.1 is an unsubstituted or substituted phenylene group and R is a group of formula ##STR1## or a precursor group for a group of formula II, said precursor group being of formula--CH.dbd.N--NH--SO.sub.2 Ar.sup.2 IIIwhere Ar.sup.2 is an aryl group.

Abstract: A crosslinkable composition of a polymeric thermoplastic and/or elastomeric material which is susceptible to scorching when processed at elevated temperatures, prior to crosslinking, in the presence of a free radical initiator, is protected against such scorching by the incorporation therein of a mixture of at least one hydroquinone compound and a sulfur accelerator. This mixture may also contain at least one monomeric allylic, methacrylic, acrylic or diene type coagent. The mixture exhibits a synergistic effect resulting in improved scorch protection for peroxide cured systems when compared with the protection afforded by the components singly.

Abstract: Oligomeric organosilicon compounds are disclosed of the formula I ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 independently of one another denote H, (C.sub.1 -C.sub.4)alkyl, (C.sub.1 -C.sub.4) alkoxy, (C.sub.1 -C.sub.4) haloalkoxy, (C.sub.1 -C.sub.4)haloalkyl, phenyl, aryl or aralkyl andZ denotes an alkylidene radical having 0-6 carbon atoms, x can be a statistical average of 1-6 andn=1-150 and . . . means that z can be bonded either to the one or the other C atom, and the particular free valency is occupied by a hydrogen.and their use in rubber mixtures and for the production of shaped articles, in particular pneumatic tires.

Abstract: Propylene polymer obtained by melt-blending of:100 parts by weight of polypropylene;from 0.01 to 10 parts by weight of a functional compound (a) comprising at least 2 acrylate groups;at least 0.005 part by weight of a sulphur-containing compound (b) chosen from thiuram sulphides; andfrom 0.01 to 5 parts by weight of a compound (c) capable of generating free radicals.

Abstract: The subject invention provides a thermoset elastomer comprising a crosslinked pseudorandom or substantially random interpolymer of: (a) from 15 to 70 weight percent of at least one .alpha.-olefin, (b) from 30 to 70 weight percent of at least one vinylidene aromatic compound, and (c) from 0 to 15 weight percent of at least one diene. The subject invention further provides a thermoplastic vulcanizate comprising the thermoset elastomers of the invention as provided in a thermoplastic polyolefin matrix. The subject invention further provides processes for preparing the inventive thermoset elastomers and thermoplastic vulcanizates, as well as parts fabricated therefrom. The inventive materials have a superior balance of properties, as compared to EPM and EPDM based materials. The subject invention also pertains to foams and methods for their preparation.

Abstract: Mixtures are disclosed of bis(silylorganyl)polysulfanes and silylorganylthiocyanates, which are produced by reacting polysulfanes with cyanides. The inorganic thiocyanate formed is subsequently allowed to react with a haloalkylalkoxysilane to form the silylorganylthiocyanate. These substances are used in plastic and rubber mixtures reinforced with silica and optionally carbon black.

Abstract: A chlorosulfonated ethylene-.alpha.-olefin copolymer composition comprising a chlorosulfonated ethylene-.alpha.-olefin copolymer, a thiuram compound, a bismaleimide compound, a nickel dialkyldithiocarbamate, and a diarylmonoamine compound, and a motorcar joint boot obtained by molding and vulcanizing the chlorosulfonated ethylene-.alpha.-olefin copolymer composition. The copolymer composition is excellent in the tensile characteristics at room temperature and low temperature, in the compression set under a low-temperature atmosphere, and in the fatigue resistance.

Abstract: Water-soluble polymers including functionalization from the group of amino groups, carboxylic acid groups, phosphonic acid groups, phosphonic ester groups, acylpyrazolone groups, hydroxamic acid groups, aza crown ether groups, oxy crown ethers groups, guanidinium groups, amide groups, ester groups, aminodicarboxylic groups, permethylated polyvinylpyridine groups, permethylated amine groups, mercaptosuccinic acid groups, alkyl thiol groups, and N-alkylthiourea groups are disclosed.

Abstract: A crosslinkable composition of a polymeric thermoplastic and/or elastomeric material which is susceptible to scorching when processed at elevated temperatures, prior to crosslinking, in the presence of a free radical initiator, is protected against such scorching by the incorporation therein of a mixture of at least one hydroquinone compound and a sulfur accelerator. This mixture may also contain at least one monomeric allylic, methacrylic, acrylic or diene type coagent. The mixture exhibits a synergistic effect resulting in improved scorch protection for peroxide cured systems when compared with the protection afforded by the components singly.

Abstract: A modified polymer prepared by terminally modifying a conjugated diene polymer obtained by polymerization using a lanthanoid-containing catalyst in an organic solvent, with an N-substituted amino active compound, and having Mw of 100,000-1,000,000, a monomodal Mw-distribution, Mw/Mn of 1.3-5, and a terminal modification of at least 50%. The modified polymer is produced by (1) polymerizing a conjugated diene by using a catalyst which is either a mixture of (i) a reaction product of a lanthanoid-containing compound with an organoaluminum hydride and then with a Lewis base, and (ii) a halo-compound, or is a reaction product of (i) with (ii) prepared by reacting a portion of conjugated diene monomer prior to reaction of (ii); and then (2) terminally modifying the obtained living polymer with an N-substituted amino active compound.

Abstract: A vulcanization accelerator combination based on di-(C.sub.6 -C.sub.12 alkyl)dithiophosphates for vulcanizing non-polar rubbers, comprising the following components: (a) a di-(C.sub.6 -C.sub.12 alkyl)dithiophosphate; (b) one or more compounds selected from the group consisting of sulphenamides, thiazoles and carbamates; (c) sulfur and/or a sulfur donor; and (d) at least one additional accelerator compound having a specific chemical structure that is different from the chemical structure of component (a) and any of the compounds used as component (b) in said accelerator combination.

Abstract: This invention relates to the discovery that tetrabenzylthiuram disulfide in combination with a bismaleimide compound and a sulfenamide compound provides for excellent vulcanization of rubbers and results in an improved final rubber vulcanizate possessing superior physical properties and reversion resistance.

Abstract: Salts of formula (III) ##STR1## wherein R.sup.1 represents CN or a C.sub.1 -C.sub.8 alkyl group, R.sub.2 a mononuclear C.sub.6 -C.sub.10 aryl group and R.sub.3 a C.sub.1 -C.sub.3 alkyl group or hydrogen; and of formula (IV) ##STR2## wherein R represents hydrogen or C.sub.1 -C.sub.3 alkyl, Aryl a C.sub.6 -C.sub.10 (substituted) phenyl group, and R', R" represent hydrogen and C.sub.1 -C.sub.4 alkyl or R'+R" together represent C.sub.4 alkylene anda process for their preparation by reaction of the thiocarbamate of a primary aliphatic amine, of a bis-amine or of cyanamide with a guanidine hydrohalide.

Abstract: Monofunctional or multifunctional isothiocyanates having the general formulaR--(N.dbd.C.dbd.S).sub.xwhere R is any organic remainder; x.gtoreq.1, or compounds which form such isothiocyanates under the influence of temperature are used in elastomeric compounds to be vulcanized as inhibitors for amines.

Abstract: Disclosed are ambient temperature-curable roofing compositions and ambient temperature-curable sheeting compositions, both of which include an elastomer or elastomer mixture such as ethylene-propylene non-conjugated diene terpolymer, butyl rubber, and mixtures thereof. Such elastomers are cured with conventional dialkylthiourea and sulfur type curatives. Also used are conventional thiuram and dithiocarbamate type accelerators. The compositions thus produced are essentially free of hexasulfide compounds which are known to have the structural formula [(CH.sub.2).sub.n NCS].sub.2 S.sub.6, wherein "n" is 4 or 5.

Abstract: In one of several methods of producing polybutadiene or a butadiene-styrene copolymer with an organolithium initiator, an organotin compound such as tetraallyltin, tetrabenzyltin and tetraphenyltin is added to the polymerization system in a period of growth of the polymer chain between a time immediately after a start of the polymerization to a time before an end of the polymerization. In another of the methods, tin tetrachloride or tin dichloride is added at an earlier time after a start of the polymerization. A polymer comprising a considerable amount of high molecular weight polymer containing the chain having a tin-carbon linkage is formed. A rubber composition for tires comprises specified amounts of the polymer described above, natural rubber, carbon black and vulcanizing agents. The rubber composition has a small loss factor and excellent fracture properties.

Abstract: A vulcanizable rubber composition including a partially hydrogenated unsaturated nitrile-conjugated diene copolymer having an iodine value of smaller than 25, a sulfur vulcanizer and a tellurium dithiocarbamate compound as a vulcanization promotor. This rubber composition provides a vulcanizate having reduced heat build-up, reduced compression set and high mechanical strength.

Abstract: A crosslinking agent suitable for acrylic rubbers, particularly for acrylic rubbers containing units of a cyanoacetic acid comonomer or a malonic acid comonomer for imparting a crosslinkability, which comprises a reaction product of formaldehyde or a polymerized formaldehyde with urea or thiourea in the presence of an acidic catalyst.

Abstract: A process for producing a diolefin polymer or copolymer, comprising the steps of polymerizing 55-100 wt % of a conjugated diolefin with 0-45 wt % of an aromatic vinyl compound as monomers in a hydrocarbon as a solvent, by using initiators: a reaction product [a1] between at least one secondary amine compound (A) and an organic lithium compound and/or a lithium amide compound [a2] of the at least one secondary amine compound (A) as well as a reaction product [b1] between at least one alcohol (B) and an organic lithium compound and/or a lithium alkoxide compound of the at least one alcohol (B). A rubber composition containing not less than 30 wt % of such a diolefin polymer or copolymer with respect to an entire rubber component is also disclosed. This rubber composition exhibits excellent abrasion resistance, high tensile strength, steering stability and low rolling resistance, and is suitable for tires, particularly, as treads of low fuel consumption tires.