A disclosed binder composition comprises a copolymer which comprises a nitrile group-containing monomer unit, an acidic group-containing monomer unit and a basic group-containing monomer unit, wherein the proportion of the nitrile group-containing monomer unit in the copolymer is 70.0 mol % or more and 99.0 mol % or less, and wherein the total proportion of the acidic group-containing monomer unit and the basic group-containing monomer unit in the copolymer is 0.8 mol % or more and 10.0 mol % or less.

A disclosed binder composition comprises a copolymer which comprises a nitrile group-containing monomer unit, an acidic group-containing monomer unit and a basic group-containing monomer unit, wherein the proportion of the nitrile group-containing monomer unit in the copolymer is 70.0 mol % or more and 99.0 mol % or less, and wherein the total proportion of the acidic group-containing monomer unit and the basic group-containing monomer unit in the copolymer is 0.8 mol % or more and 10.0 mol % or less.

A toner comprising a toner particle including a crystalline resin, wherein where a complex modulus of elasticity at 30° C. is denoted by G*(30) and a complex modulus of elasticity at 50° C. is denoted by G*(50) in dynamic viscoelasticity measurement of the toner, and where a peak temperature of an exothermic peak derived from the crystalline resin in a temperature lowering process after a temperature is raised to 150° C., is denoted by Tc (° C.), a peak temperature of an endothermic peak derived from the crystalline resin in a temperature raising process after the temperature lowering process, is denoted by Tm (° C.), and an endothermic quantity is denoted by ΔH (J/g) in differential scanning calorimetry of the toner, G*(30), G*(50), Tc, Tm and ΔH satisfy specific relationships.

A toner comprising a toner particle including a crystalline resin, wherein where a complex modulus of elasticity at 30° C. is denoted by G*(30) and a complex modulus of elasticity at 50° C. is denoted by G*(50) in dynamic viscoelasticity measurement of the toner, and where a peak temperature of an exothermic peak derived from the crystalline resin in a temperature lowering process after a temperature is raised to 150° C., is denoted by Tc (° C.), a peak temperature of an endothermic peak derived from the crystalline resin in a temperature raising process after the temperature lowering process, is denoted by Tm (° C.), and an endothermic quantity is denoted by ΔH (J/g) in differential scanning calorimetry of the toner, G*(30), G*(50), Tc, Tm and ΔH satisfy specific relationships.

A toner having a toner particle containing a binder resin having a first resin and a second resin, wherein the first resin is a crystalline resin, the second resin is an amorphous resin, the first resin has a first monomer unit, a second monomer unit and a third monomer unit each having specific structure, a content of the first monomer unit and a content of the third monomer unit in the first resin satisfy specific range, and an SP value of the second monomer unit satisfies specific range, the second resin contains at least one of resin selected from the group consisting of a vinyl-based resin and a specific hybrid resin, a cross section of the toner has a domain-matrix structure formed of a matrix including the first resin and domains including the second resin, and a number average diameter of the domains is 0.10 to 2.00 μm.

A toner having a toner particle containing a binder resin having a first resin and a second resin, wherein the first resin is a crystalline resin, the second resin is an amorphous resin, the first resin has a first monomer unit, a second monomer unit and a third monomer unit each having specific structure, a content of the first monomer unit and a content of the third monomer unit in the first resin satisfy specific range, and an SP value of the second monomer unit satisfies specific range, the second resin contains at least one of resin selected from the group consisting of a vinyl-based resin and a specific hybrid resin, a cross section of the toner has a domain-matrix structure formed of a matrix including the first resin and domains including the second resin, and a number average diameter of the domains is 0.10 to 2.00 μm.

Finely divided, cationic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of ethylenically unsaturated monomers in an aqueous liquid containing a cationic prepolymer as a dispersant, wherein the cationic prepolymer is prepared in the presence of at least one polymerisation initiator by polymerisation of (a) from 15 to 45% by weight of at least one ethylenically unsaturated monomer comprising at least one quaternary ammonium group; (b) from 5 to 80% by weight of at least one optionally substituted styrene; (c) from 0 to 50% by weight of at least one C 1-12 alkyl (meth) acrylate; (d) from 0 to 10% by weight of at least one ethylenically unsaturated monomer comprising an acid group; (e) from 0 to 10% by weight of at least one ethylenically unsaturated monomer comprising an amine group; and (f) from 0 to 20% by weight of at least one non-ionic ethylenically unsaturated monomer differing from (b), (c) and (e), the sum of (a)+(b)+(c)+(d)+(e)+(f) being 100% by weight, in a first emulsion polymerisation in the presence of at least one non-ionic emulsifier, and thereafter, in the aqueous liquid containing the cationic prepolymer a second emulsion polymerisation is carried out, in the presence of at least one polymerisation initiator, of a monomer mixture comprising (i) from 10 to 70% by weight of at least one of an optionally substituted styrene or (meth) acrylonitrile; (ii) from 30 to 90% by weight of at least one CMS alkyl (meth) acrylate; (iii) from 0 to 30% by weight of at least one vinyl ester of linear or branched C.sub.1-30 carboxylic acids; and (iv) from 0 to 30% by weight of at least one non-ionic ethylenically unsaturated monomer differing from (i), (ii) and (iii), the sum of (i)+(ii)+(iii)+(iv) being 100% by weight, and the first emulsion polymerisation and/or the second emulsion polymerisation is optionally carried out in the presence of from 0 to 10% by weight of at least one polymerisation regulator. The polymer dispersions according to the present invention are suitable for use as sizing agents for paper, board and card board.

Finely divided, cationic, aqueous polymer dispersion which is obtainable by emulsion polymerisation of ethylenically unsaturated monomers in an aqueous liquid containing a cationic prepolymer as a dispersant, wherein the cationic prepolymer is prepared in the presence of at least one polymerisation initiator by polymerisation of (a) from 15 to 45% by weight of at least one ethylenically unsaturated monomer comprising at least one quaternary ammonium group; (b) from 5 to 80% by weight of at least one optionally substituted styrene; (c) from 0 to 50% by weight of at least one C 1-12 alkyl (meth) acrylate; (d) from 0 to 10% by weight of at least one ethylenically unsaturated monomer comprising an acid group; (e) from 0 to 10% by weight of at least one ethylenically unsaturated monomer comprising an amine group; and (f) from 0 to 20% by weight of at least one non-ionic ethylenically unsaturated monomer differing from (b), (c) and (e), the sum of (a)+(b)+(c)+(d)+(e)+(f) being 100% by weight, in a first emulsion polymerisation in the presence of at least one non-ionic emulsifier, and thereafter, in the aqueous liquid containing the cationic prepolymer a second emulsion polymerisation is carried out, in the presence of at least one polymerisation initiator, of a monomer mixture comprising (i) from 10 to 70% by weight of at least one of an optionally substituted styrene or (meth) acrylonitrile; (ii) from 30 to 90% by weight of at least one CMS alkyl (meth) acrylate; (iii) from 0 to 30% by weight of at least one vinyl ester of linear or branched C.sub.1-30 carboxylic acids; and (iv) from 0 to 30% by weight of at least one non-ionic ethylenically unsaturated monomer differing from (i), (ii) and (iii), the sum of (i)+(ii)+(iii)+(iv) being 100% by weight, and the first emulsion polymerisation and/or the second emulsion polymerisation is optionally carried out in the presence of from 0 to 10% by weight of at least one polymerisation regulator. The polymer dispersions according to the present invention are suitable for use as sizing agents for paper, board and card board.

Provided is a magnetic toner having a toner particle containing a binder resin and a magnetic body, wherein the binder resin contains a polymer A having a first monomer unit and a second monomer unit, the first polymerizable monomer is at least one selected from the group consisting of the (meth)acrylic acid esters having C.sub.18-36 alkyl groups, a content of the first monomer unit and a content of the second monomer unit based on the total moles of all monomer units in the polymer A are respectively 5.0 to 60.0 mol % and 20.0 to 95.0 mol %, and assuming that an SP value of the first monomer unit and the second monomer unit are taken as SP.sub.11 (J/cm.sup.3).sup.0.5 and SP.sub.21(J/cm.sup.3).sup.0.5, respectively, 3.00≤(SP.sub.21−SP.sub.11)≤25.00 is satisfied, and an oil absorption of the magnetic body is 5 to 40 ml/100 g.

Provided is a magnetic toner having a toner particle containing a binder resin and a magnetic body, wherein the binder resin contains a polymer A having a first monomer unit and a second monomer unit, the first polymerizable monomer is at least one selected from the group consisting of the (meth)acrylic acid esters having C.sub.18-36 alkyl groups, a content of the first monomer unit and a content of the second monomer unit based on the total moles of all monomer units in the polymer A are respectively 5.0 to 60.0 mol % and 20.0 to 95.0 mol %, and assuming that an SP value of the first monomer unit and the second monomer unit are taken as SP.sub.11 (J/cm.sup.3).sup.0.5 and SP.sub.21(J/cm.sup.3).sup.0.5, respectively, 3.00≤(SP.sub.21−SP.sub.11)≤25.00 is satisfied, and an oil absorption of the magnetic body is 5 to 40 ml/100 g.