Toner
A toner including a toner particle containing a binder resin and an ester compound, wherein the binder resin contains a styrene-acrylic-based resin, the styrene-acrylic-based resin contains a specific unit, the ester compound has a specific structure, and a molar ratio of the specific unit to the ester compound is 0.5 to 1.5.
1. A toner, comprising:
a toner particle comprising a binder resin and an ester compound;
the binder resin comprising a styrene-acrylic-based resin and optionally comprising a low molecular weight polystyrene, the styrene-acrylic-based resin being a copolymer of monomers comprising (i) styrene, (ii) n-lauryl acrylate or n-lauryl methacrylate and (iii) crosslinking agent;
the styrene-acrylic-based resin containing a unit represented by formula (1) which is derived from the group (ii)
where R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 12 carbon atoms; and
the ester compound comprising a structure represented by formulae (2) or (3)
where R 3 represents an alkylene group having 2 to 4 carbon atoms, and R 4 and R 5 independently represent a linear alkyl group having 14 to 22 carbon atoms, wherein
a molar ratio of the unit represented by formula (1) to the ester compound is 0.5 to 1.5,
the styrene-acrylic-based resin is contained in the binder resin at 90.0% by mass or more,
an amount of the styrene for polymerizing the styrene-acrylic-based resin is 70.0 to 84.6% by mass with respect to the total mass of the monomers and the low molecular weight polystyrene, and
an amount of the crosslinking agent for polymerizing the styrene-acrylic-based resin is 0.5 to 1.5% by mass with respect to the total mass of the monomers and the low molecular weight polystyrene.
2. The toner according to claim 1 , wherein the ester compound is contained in the toner particle at 5.0 to 25.0% by mass with respect to the binder resin.
3. The toner according to claim 1 , wherein the binder resin comprises said low molecular weight polystyrene.
4. The toner according to claim 1 , wherein the styrene-acrylic-based resin contains 1.0 to 15.0% by mass of the unit represented by formula (1).
5. The toner according to claim 1 , wherein R 3 represents an alkylene group having 2 carbon atoms, and R 4 and R 5 independently represent a linear alkyl group having 14 to 18 carbon atoms.
6. The toner according to claim 1 , wherein the styrene-acrylic-based resin further comprises a unit represented by formula (4)
where m+n is an integer of 2 or more, R 6 and R 9 independently represent a hydrogen atom or a methyl group, and R 7 and R 8 independently represent a linear or branched hydrocarbon group having 2 to 12 carbon atoms.
7. The toner according to claim 1 , wherein a domain of the ester compound exists in a cross section of the toner particle observed with a scanning transmission electron microscope,
an average number of the domain in the cross section is 100 or more, and
an average major diameter of the domain is 1.0 μm or less.
8. The toner according to claim 1 , wherein the monomers further comprise n-butyl acrylate.
9. The toner according to claim 1 , wherein R 1 represents a hydrogen atom.
10. The toner according to claim 1 , wherein R 1 represents a methyl group.