White toner and method for producing same
A white toner comprising a toner particle including a binder resin, an inorganic white pigment, and a polyvalent metal salt compound, wherein the inorganic white pigment has an acidic group at a surface thereof; an amount of the inorganic white pigment in the toner particle is 10% to 50% by volume; the polyvalent metal salt compound is a specific compound; an absolute value of the difference between an SP value (J/cm 3 ) 1/2 of the binder resin and that of the polyvalent metal salt compound is 0.0 to 6.0; and an amount of the polyvalent metal salt compound, an amount of a polyvalent metal, the amount of the inorganic white pigment, and an amount of the acidic group at a surface of the inorganic white pigment satisfy a specific relationship.
1. A white toner comprising
a toner particle that includes a binder resin, an inorganic white pigment and a polyvalent metal salt compound, wherein
the inorganic white pigment has an acidic group at a surface thereof, and a volume amount of the inorganic white pigment in the toner particle is 10% by volume to 50% by volume;
the polyvalent metal salt compound is at least one selected from the group consisting of compounds represented by following formulae (1) and (2):
in the formula (1), R 1 is each independently an organic group having from 6 to 40 carbon atoms, M 1 is a divalent metal, X 1 is a hydroxyl group or a halogen group, p 1 represents an integer of 1 to 2, and q 1 represents an integer of 0 to 1,
in the formula (2), R 2 is each independently an organic group having 6 to 40 carbon atoms, M 2 is a trivalent metal, X 2 is each independently a hydroxyl group or a halogen group, p 2 represents an integer of 1 to 3, and q 2 represents an integer of 0 to 2,
an absolute value of the difference between an SP value (J/cm 3 ) 1/2 of the binder resin and the SP value (J/cm 3 ) 1/2 of the polyvalent metal salt compound is 0.0 to 6.0;
wherein when an amount of the polyvalent metal salt compound in the toner particle is denoted by Wa (% by mass),
an amount of a polyvalent metal in the polyvalent metal salt compound is denoted by Ma (μmol/g),
a mass amount of the inorganic white pigment in the toner particle is denoted by Wp (% by mass), and
an amount of the acidic group at the surface of the inorganic white pigment is denoted by Ap (μmol/g), the following is satisfied:
0.1≤( Wa×Ma )/( Wp×Ap )≤2.0.
2. The white toner according to claim 1 , wherein the polyvalent metal salt compound is at least one selected from the group consisting of compounds represented by following formulas (3) and (4):
in the formula (3), R 3 is each independently an unsubstituted or hydroxy-substituted alkyl group having 8 to 30 carbon atoms, or a phenyl group unsubstituted or substituted with an alkyl group having 1 to 8 carbon atoms, A 3 is each independently —C(═O)O— or —S(═O) 2 O—, M 3 is a divalent metal, X 3 is a hydroxyl group or a halogen group, p 3 represents an integer of 1 to 2, and q 3 represents an integer of 0 to 1,
in the formula (4), R 4 is each independently an unsubstituted or hydroxyl-substituted alkyl group having 8 to 30 carbon atoms or a phenyl group unsubstituted or substituted with an alkyl group having 1 to 8 carbon atoms, A 4 is each independently —C(═O)O— or —S(═O) 2 O—, M 4 is a trivalent metal, X 4 is each independently a hydroxyl group or a halogen group, p 4 represents an integer of 1 to 3, and q 4 represents an integer of 0 to 2.
3. The white toner according to claim 1 , wherein the SP value (J/cm 3 ) 1/2 of the polyvalent metal salt compound is 15.0 to 30.0.
4. The white toner according to claim 1 , wherein the polyvalent metal salt compound is a fatty acid metal salt.
5. The white toner according to claim 1 , wherein the binder resin includes a polyester resin.
6. The white toner according to claim 5 , wherein an amount of a structure in which a propylene oxide adduct of bisphenol A is condensed in a structure in which a dialcohol component contained in the polyester resin is condensed is 50% by mass to 100% by mass.
7. The white toner according to claim 1 , wherein the inorganic white pigment includes titanium oxide.
8. The white toner according to claim 1 , wherein the inorganic white pigment includes calcium titanate.
9. The white toner according to claim 1 , wherein the polyvalent metal salt compound includes a fatty acid aluminum salt.
10. The white toner according to claim 1 , wherein the polyvalent metal salt compound includes at least one selected from the group consisting of hydroxyaluminum distearate and hydroxyaluminum dilaurate.
11. The white toner according to claim 1 , wherein the toner is a melt-kneaded pulverized toner.
12. A method for producing the white toner according to claim 1 , comprising the steps of:
melt-kneading a mixture including the binder resin, the inorganic white pigment, and the polyvalent metal salt compound to obtain a melt-kneaded product, and
pulverizing the obtained melt-kneaded product to obtain the toner particle.