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US 9,785,072 B2Granted
Electrophotographic toner using bioplastic and production method thereof
AssigneeCasio Computer Co., Ltd.
InventorsKenji Kihira, Hideki Ikeda, Yuichiro Iegaki, Yuta Kan, Hideki Hasegawa
Life of this patent
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Abstract
An electrophotographic toner which is excellent in grindability, fixing property and durability by being obtained via a step of melt-kneading a mixture containing an amorphous bioplastic having a weight-average molecular weight (Mw) of 55000 to 120000, a terpene phenol resin, and a styrene acrylic resin having a weight-average molecular weight (Mw) of 85500 to 118000 so as to obtain a kneaded mixture, and a step of grinding the kneaded mixture after hardening.
Claims10
An electrophotographic toner comprising:
- (a) an amorphous polylactic acid having a weight-average molecular weight (Mw) of 55000 to 120000 and (b) grinding aids comprising (i) a terpene phenol resin contained in an amount of 15 to 25% by mass with respect to a toner mass and having a softening temperature of 125° C. to 150° C., and (ii) a styrene acrylic resin contained in an amount of 8 to 12% by mass with respect to a toner mass and having a weight-average molecular weight (Mw) of 85500 to 118000, the toner mass being defined as a total mass of toner raw materials including internal additives, and excluding external additives,
- wherein the grinding aids each have a weight-average degree of polymerization of 500 to 5000.
A method of producing an electrophotographic toner comprising:
- a step of melt-kneading a mixture containing (a) an amorphous polylactic acid having a weight-average molecular weight (Mw) of 55000 to 120000 and (b) grinding aids comprising (i) a terpene phenol resin contained in an amount of 15 to 25% by mass with respect to a toner mass and having a softening temperature of 125° C. to 150° C., and (ii) a styrene acrylic resin contained in an amount of 8 to 12% by mass with respect to a toner mass and having a weight-average molecular weight (Mw) of 85500 to 118000, to obtain a kneaded mixture, the toner mass being defined as a total mass of toner raw materials including internal additives and excluding external additives;
- and
- a step of grinding the kneaded mixture after hardening,
- wherein the grinding aids each have a weight-average degree of polymerization of 500 to 5000.
1 more element
Dependencies are inferred from the claim text.