Abstract: The present invention provides colored spherical fine particles comprising fine particles and a coloring agent uniformly dispersed therein.The colored spherical fine particles of the present invention can be produced by reaction an unsaturated polymer with an aldehyde group- and carboxyl group-containing organic compound in the present of a Lewis acid or a protonic acid to obtain a modified polymer, dissolving or dispersing the modified polymer, together with a coloring agent, in a polymerization monomer, and polymerizing the polymerizable monomer.The colored spherical fine particles of the present invention can be used as a toner for electrostatic image development, as they are. Further, the dispersion composition obtained by dispersing the colored spherical fine particles of the present invention in a medium, can be used as a heat-sensitive transfer ink or as a back coating agent for heat-sensitive transfer ink ribbon or magnetic recording medium.

Abstract: A rubber composition comprising a rubbery polymer and a modified liquid polymer. The modified liquid polymer is obtained by reacting a liquid polymer having at least one carbon-carbon double bond in the molecule with an organic compound having the group --CH.dbd.N-- and an organic acid halide having the group --COX where X is halogen, in the presence of a Friedel-Crafts catalyst.

Abstract: Disclosed herein is a process for the preparation of a toner, which comprises dissolving or dispersing a compound having at least one >C.dbd.N.sup..sym. < bond in its molecule and a colorant in a vinyl monomer and then suspension-polymerizing the vinyl monomer in an aqueous dispersion medium.

Abstract: Disclosed is a magnetic recording medium comprising a non-magnetic support and a magnetic layer composed mainly of a ferromagnetic powder and a binder, which is formed on one surface of the support, and an optional backcoat layer composed mainly of a non-magnetic powder and a binder, which is formed on the other surface of the support. At least one of the magnetic layer and the backcoat layer contains a compound having at least one >C.dbd.N.sup..sym. < bond in the molecule. When preparing the magnetic recording medium, the magnetic powder or non-magnetic powder may be surface-treated with the >C.dbd.N.sup..sym. < group-containing compound.

Abstract: A compatibilizing agent for improving the compatibility between different polymers which are poorly compatible with each other, comprising a polymer having at least one heterocyclic ring structure containing a >C.dbd.N.sup..sym. < bond in the molecule and a polymer blend composition comprising different polymers which are poorly compatible with each other and such a compatibilizing agent.

Abstract: A crosslinked polymer having shape memorizing property, said crosslinked polymer being obtained by thermally reversibly crosslinking a base polymer composed of a blocked copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the base polymer having a glass transition temperature of 70.degree. to 140.degree. C., and the glass transition temperature being higher than the dissociation temperature of the thermally reversible crosslinkage contained in the crosslinkage polymer.

Abstract: A method for improving the physical properties of a rubber having --C(CH.sub.3).dbd.C-- type unsaturated bonds, characterized by subjecting said rubber to two reactions consisting of a modification reaction by Lewis acid and a carboxylation reaction in any desired order.

Abstract: A method for modifying a rubber having unsaturated bonds, characterized by reacting said rubber with (a) an organic compound (I) having a group represented by the formula --CH.dbd.N-- and (b) an organic acid halide (II) having a group represented by the formula --COX (X is a halogen atom), in the place of a Lewis acid.

Abstract: A process for the addition reaction of an unsaturated organic compound, except a rubber, having at least one carbon-carbon double bond in a molecule, which comprises reacting the unsaturated organic compound with an organic compound having a carboxyl group and an aldehyde group in the presence of a Lewis acid.

Abstract: A cis-1,4-polyisoprene rubber composition capable of giving a vulcanizate having improved strength, said composition comprising (1) a synthetic cis-1,4-polyisoprene rubber having epoxy groups, (2) a compound having at least two primary amino groups, and (3) a sulfur vulcanization system.

Abstract: A method for modifying a rubber having an unsaturated carbon bond which comprises reacting the rubber with an organic compound represented by the general formula ##STR1## wherein --R represents a hydrocarbon group, and --X is --H, --CN or ##STR2## in which --Y represents an organic atomic grouping, in the presence of a Lewis acid to introduce an ester group. Optionally, the ester group introduced is converted into a carboxyl group by chemically treating the reaction product.

Abstract: A method for modifying cis-1,4-polyisoprene rubber, which comprises reacting a diisocyanate with a primary diamine in the presence of the cis-1,4-polyisoprene rubber.

Abstract: A process for modifying a rubber, which comprises reacting a rubber having an unsaturated carbon linkage with an organic compound having a carboxyl group and an aldehyde group in the presence of an acid catalyst.

Abstract: A modified rubber composition comprising a blend of (a) a modified rubber obtained by reaction a rubber having an unsaturated carbon linkage with an organic compound having a carboxyl group and an aldehyde group in the presence of an acid catalyst, and (b) carbon black.