Toners for electrostatic-image development
View Patent ↗To provide an emulsion polymerized agglomerated toner for electrostatic charge image which is excellent in the fixing property even at a high temperature without deteriorating other properties and which does not emit an odor offensive to people, and a process for its production. An emulsion polymerized agglomerated toner characterized in that the odor index of aliphatic aldehydes measured by gas chromatography is at most 300, and an emulsion polymerized agglomerated toner which is an emulsion polymerized agglomerated toner obtainable via a polymerization step, a flocculation step and an aging step, characterized in that an emulsion polymerized latex before the flocculation step is a latex having a peroxide value of at most 30.
1. A method for making an emulsion polymerized agglomerated toner comprising a crosslinked styrene resin binder, the method comprising
(1) polymerization, which is carried out by seed polymerization in the presence of a dispersion of a wax in the form of particles having an average diameter of from 0.01 μm to 3 μm and a redox initiator, wherein the wax is at least one member selected from the group consisting of an olefin wax, an ester wax having a long chain alkyl group, a ketone having a long chain alkyl group, and a long chain aliphatic alcohol, thereby forming a latex of primary particles comprising said crosslinked styrene resin and said wax,
(2) mixing said latex of primary particles and a dispersion of colorant particles, thereby forming an emulsion polymerized latex having a peroxide value of at most 30,
(3) flocculating primary particles of the emulsion polymerized latex thereby forming agglomerates of primary particles,
(4) fusing the primary particles of the agglomerates to one another, and
(5) washing and drying the fused agglomerates, thereby forming said toner, the toner having a volume average particle diameter of from 3 to 8 μm,
and
wherein an odor index as calculated from the contents of aliphatic aldehydes in the toner measured by gas chromatography and the odor threshold values of the aliphatic aldehydes, is at most 300.
2. The method according to claim 1 , wherein the odor index of 1-octanal among the aliphatic aldehydes is at most 280.
3. The method according to claim 1 , wherein the odor index is at most 200.
4. The method according to claim 1 , wherein the odor index is at most 100.
5. The method according to claim 2 , wherein the odor index of 1-octanal is at most 240.
6. The method according to claim 2 , wherein the odor index of 1-octanal is at most 90.
7. The method according to claim 1 , wherein an odor index of aliphatic acids is at most 2.
8. The method according to claim 1 , wherein an odor index of aliphatic acids is at most 1.5.
9. The method according to claim 1 , wherein an odor index of aliphatic acids is at most 1.0.
10. The method according to claim 1 , wherein the peroxide value is at most 10.
11. The method according to claim 1 , wherein the redox initiator comprises hydrogen peroxide and ascorbic acid.