Toner compositions
View Patent ↗Single component toners having a core with a first latex having a specific glass transition temperature and molecular weight, further having a shell surrounding the core with a second latex having a specific glass transition temperature and molecular weight, and additives added thereto, and processes for producing the same. In embodiments, the toner is a non-magnetic single component toner produced by emulsion aggregation methods.
1. A single component developer comprising an emulsion aggregation toner comprising:
a core comprising a first latex having a glass transition temperature from about 45° C. to about 54° C. and a molecular weight from about 33,000 to about 37,000;
a shell surrounding said core comprising a second latex having a glass transition temperature from about 55° C. to about 65° C. and a molecular weight from about 33,000 to about 37,000; and
at least two additives,
wherein the toner possesses a gloss of from about 20 ggu to about 120 ggu.
2. The single component developer according to claim 1 , wherein the first latex has a glass transition temperature from about 49° C. to about 53° C. and a molecular weight from about 34,000 to about 36,000, and the latex in the shell has a glass transition temperature from about 56° C. to about 61° C. and a molecular weight from about 34,000 to about 36,000.
3. The single component developer according to claim 1 , wherein the first latex is selected from the group consisting of styrene acrylates, styrene butadienes, styrene methacrylates, and combinations thereof, the latex in the shell is selected from the group consisting of styrene acrylates, styrene butadienes, styrene methacrylates, and combinations thereof, and the at least two additives are selected from the group consisting of silicas, metal oxides, colloidal silicas, strontium titanates, and combinations thereof.
4. The single component developer according to claim 1 , wherein the at least two additives include a first additive comprising a silica having a surface area from about 25 nm to about 200 nm present in an amount from about 2% to about 5% by weight of the toner, and a second surface additive comprising a metal oxide having a surface area from about 1 nm to about 20 nm present in an amount from about 0.2% to about 2.5% by weight of the toner.
5. The single component developer according to claim 1 , wherein the at least two additives include a first additive comprising a silica having a surface area from about 40 nm to about 150 nm present in an amount from about 3% to about 4% by weight of the toner, and a second surface additive comprising a metal oxide having a surface area from about 2 nm to about 15 nm present in an amount from about 1% to about 2% by weight of the toner.
6. The single component developer according to claim 1 , wherein the toner comprises a non-magnetic emulsion aggregation toner and further comprises a colorant, and optionally one or more components selected from the group consisting of surfactants, coagulants, and optionally mixtures thereof.
7. The single component developer of claim 1 , wherein the first latex comprises a styrene/butyl acrylate copolymer comprising from about 70% by weight to about 78% by weight styrene and from about 22% by weight to about 30% by weight butyl acrylate, and the second latex comprises a styrene/butyl acrylate copolymer comprising from about 79% by weight to about 85% by weight styrene and from about 15% by weight to about 21% by weight butyl acrylate.
8. The single component developer of claim 1 , wherein the first latex comprises a styrene/butyl acrylate copolymer comprising from about 74% by weight to about 77% by weight styrene and from about 21% to about 25% by weight butyl acrylate, and the second latex comprises a styrene/butyl acrylate copolymer comprising from about 81% by weight to about 83% by weight styrene, and from about 17% to about 19% by weight butyl acrylate.
9. The single component toner developer of claim 1 , wherein the toner possesses a triboelectric value of from about 35 μC/g to about 75 μC/g, a circularity from about 0.93 to about 0.99, a surface area from about 1 m 2 /g to about 2.5 m 2 /g, and a particle size distribution from about 1 to about 1.5.
10. The single component developer according to claim 1 , wherein the toner possesses a triboelectric value of from about 44 μC/g to about 61 μC/g, a circularity from about 0.96 to about 0.985, a surface area from about 1.25 m 2 /g to about 2 m 2 /g, and a particle size distribution from about 1.15 to about 1.25.
11. A single component developer comprising an emulsion aggregation toner comprising:
a core comprising a first latex selected from the group consisting of styrene acrylates, styrene butadienes, styrene methacrylates, and combinations thereof having a glass transition temperature from about 45° C. to about 54° C. and a molecular weight from about 33,000 to about 37,000;
a shell surrounding said core comprising a second latex selected from the group consisting of styrene acrylates, styrene butadienes, styrene methacrylates, and combinations thereof having a glass transition temperature from about 55° C. to about 65° C. and a molecular weight from about 33,000 to about 37,000; and
at least two additives selected from the group consisting of silicas, metal oxides, colloidal silicas, strontium titanates, and combinations thereof,
wherein the toner possesses a gloss of from about 20 ggu to about 120 ggu.
12. The single component developer according to claim 11 , wherein the first latex has a glass transition temperature from about 49° C. to about 53° C. and a molecular weight from about 34,000 to about 36,000, the latex in the shell has a glass transition temperature from about 56° C. to about 61° C. and a molecular weight from about 34,000 to about 36,000, and the at least two additives include a first additive comprising a silica having a surface area from about 25 nm to about 200 nm present in an amount from about 2% to about 5% by weight of the toner, and a second surface additive comprising a metal oxide having a surface area from about 1 nm to about 20 nm present in an amount from about 0.2% to about 2.5% by weight of the toner.
13. The single component developer according to claim 11 , wherein the toner comprises an emulsion aggregation toner and further comprises a colorant, and optionally one or more components selected from the group consisting of surfactants, coagulants, and optionally mixtures thereof, and the at least two additives include a first additive comprising a silica having a surface area from about 40 nm to about 150 nm present in an amount from about 3% to about 4% by weight of the toner, and a second surface additive having a surface area from about 2 nm to about 15 nm present in an amount from about 1% to about 2% by weight of the toner.
14. The single component developer according to claim 11 , wherein the first latex comprises a styrene/butyl acrylate copolymer comprising from about 70% by weight to about 78% by weight styrene and from about 22% by weight to about 30% by weight butyl acrylate, the second latex comprises a styrene/butyl acrylate copolymer comprising from about 79% by weight to about 85% by weight styrene and from about 15% by weight to about 21% by weight butyl acrylate, and the toner possesses a triboelectric value of from about 35 μC/g to about 75 μC/g, a circularity from about 0.93 to about 0.99, a surface area from about 1 m 2 /g to about 2.5 m 2 /g, and a particle size distribution from about 1 to about 1.5.
15. A process comprising:
contacting a latex having a glass transition temperature from about 45° C. to about 54° C. and a molecular weight from about 33,000 to about 37,000, an aqueous colorant dispersion, and a wax dispersion having a melting point of from about 70° C. to about 85° C. to form a blend;
mixing the above blend with a coagulant;
heating the mixture to form an aggregated suspension;
adding a base to increase the pH to a value of from about 4 to about 7;
heating the aggregated suspension to coalesce the aggregated suspension thereby forming a toner core;
adding a second latex having a glass transition temperature from about 55° C. to about 65° C. and a molecular weight from about 33,000 to about 37,000 to the aggregated suspension, wherein the second latex forms a shell over said toner core;
adding at least two additives to said toner; and
recovering said toner
wherein the toner possesses a gloss of from about 20 ggu to about 120 ggu.
16. The process of claim 15 , wherein the first latex is selected from the group consisting of styrene acrylates, styrene butadienes, styrene methacrylates, and combinations thereof having a glass transition temperature from about 49° C. to about 53° C. and a molecular weight from about 34,000 to about 36,000, the second latex is selected from the group consisting of styrene acrylates, styrene butadienes, styrene methacrylates, and combinations thereof having a glass transition temperature from about 56° C. to about 61° C. and a molecular weight from about 34,000 to about 36,000, the wax has a melting point of from about 75° C. to about 81° C., and the coagulant comprises a polyaluminum chloride or a polymetal silicate.
17. The process according to claim 15 , wherein the at least two additives are selected from the group consisting of silicas, metal oxides, colloidal silicas, strontium titanates, and combinations thereof, and wherein the at least two additives include a first additive having a surface area from about 25 nm to about 200 nm present in an amount from about 2% to about 5% by weight of the toner, and a second surface additive having a surface area from about 1 nm to about 20 nm present in an amount from about 0.2% to about 2.5% by weight of the toner.
18. The process according to claim 15 , wherein the at least two additives include a first additive comprising a silica having a surface area from about 40 nm to about 150 nm present in an amount from about 3% to about 4% by weight of the toner, and a second surface additive having a surface area from about 2 nm to about 15 nm present in an amount from about 1% to about 2% by weight of the toner.
19. The process according to claim 15 , wherein the first latex comprises a styrene/butyl acrylate copolymer comprising from about 70% by weight to about 78% by weight styrene and from about 22% by weight to about 30% by weight butyl acrylate, and the second latex comprises a styrene/butyl acrylate copolymer comprising from about 79% by weight to about 85% by weight styrene and from about 15% by weight to about 21% by weight butyl acrylate.
20. A single component toner produced by the process of claim 15 , wherein the toner possesses a triboelectric value of from about 35 μC/g to about 75 μC/g, a circularity from about 0.93 to about 0.99, a surface area from about 1 m 2 /g to about 2.5 m 2 /g, and a particle size distribution from about 1 to about 1.5.