A toner including toner particles having a resin component containing a crystalline resin and an amorphous resin, in which the resin component contains a tetrahydrofuran-insoluble component, and the content of the tetrahydrofuran-insoluble component with respect to the content of the resin component is 5.0% to 80.0% by mass, wherein a maximum endothermic peak temperature of the tetrahydrofuran-insoluble component is 55.0 to 80.0° C., and the amount of heat absorption in the maximum endothermic peak of the tetrahydrofuran-insoluble component is 10.0 to 80.0 Pa, and toner particles have a structure which comprises a matrix containing the crystalline resin and domains containing the amorphous resin.

A toner has a toner particle containing a binder resin having a first resin and a second resin. The first resin is a crystalline resin, the second resin is an amorphous resin, and the first resin has a first monomer unit, a second monomer unit and a third monomer unit, each having a specific structure. A content of the first monomer unit a content of the third monomer unit in the first resin, and an SP value of the second monomer unit all satisfy a specific ranges, and the second resin contains at least one vinyl-based resin and/or specific hybrid resin, with a cross section of the toner having a domain-matrix structure formed of a matrix including the first resin and domains including the second resin, a number average diameter of the domains being 0.10 to 2.00 μm.

A toner has a toner particle containing a binder resin having a first resin and a second resin. The first resin is a crystalline resin, the second resin is an amorphous resin, and the first resin has a first monomer unit, a second monomer unit and a third monomer unit, each having a specific structure. A content of the first monomer unit a content of the third monomer unit in the first resin, and an SP value of the second monomer unit all satisfy a specific ranges, and the second resin contains at least one vinyl-based resin and/or specific hybrid resin, with a cross section of the toner having a domain-matrix structure formed of a matrix including the first resin and domains including the second resin, a number average diameter of the domains being 0.10 to 2.00 μm.

A latex composition has a latex of a carboxyl group-containing conjugated diene rubber and a metal compound including a trivalent or higher metal, wherein a content of the metal compound is 0.1 to 1.5 parts by weight, based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber.

A latex composition has a latex of a carboxyl group-containing conjugated diene rubber and a metal compound including a trivalent or higher metal, wherein a content of the metal compound is 0.1 to 1.5 parts by weight, based on 100 parts by weight of the carboxyl group-containing conjugated diene rubber.

Provided is a method of preparing an acrylonitrile-based copolymer for a carbon fiber, which comprises: preparing a reaction solution including a monomer mixture comprising a sulfonate-based monomer represented by Chemical Formula 1, a carboxylic acid-based monomer, and an acrylonitrile-based monomer and an organic solvent; and subjecting the reaction solution to polymerization, wherein the monomer mixture comprises the sulfonate-based monomer represented by Chemical Formula 1 at 0.55 to 1.6 mol %.

Provided is a method of preparing an acrylonitrile-based copolymer for a carbon fiber, which comprises: preparing a reaction solution including a monomer mixture comprising a sulfonate-based monomer represented by Chemical Formula 1, a carboxylic acid-based monomer, and an acrylonitrile-based monomer and an organic solvent; and subjecting the reaction solution to polymerization, wherein the monomer mixture comprises the sulfonate-based monomer represented by Chemical Formula 1 at 0.55 to 1.6 mol %.

Provided is an acrylonitrile-based copolymer for a carbon fiber which includes a sulfonate-based monomer unit, a carboxylic acid-based monomer unit, and an acrylonitrile-based monomer unit, and the acrylonitrile-based copolymer for a carbon fiber includes the sulfonate-based monomer unit at 0.55 to 1.55 mol %, and the carboxylic acid-based monomer unit at 0.60 to 1.40 mol %.

Provided is an acrylonitrile-based copolymer for a carbon fiber which includes a sulfonate-based monomer unit, a carboxylic acid-based monomer unit, and an acrylonitrile-based monomer unit, and the acrylonitrile-based copolymer for a carbon fiber includes the sulfonate-based monomer unit at 0.55 to 1.55 mol %, and the carboxylic acid-based monomer unit at 0.60 to 1.40 mol %.

Provided is an acrylonitrile-based copolymer for a carbon fiber which includes a sulfonate-based monomer unit, a carboxylic acid-based monomer unit, and an acrylonitrile-based monomer unit, and the acrylonitrile-based copolymer for a carbon fiber includes the sulfonate-based monomer unit at 0.55 to 1.55 mol %, and the carboxylic acid-based monomer unit at 0.60 to 1.40 mol %.