Sanyo Chemical Industries, Ltd.

Takashi Akutagawa

Tsuyoshi Izumi

Masakazu Iwata

Tsuyosi Izumi

Yasuhiro Ono

Tadao Takikawa

Masaru Honda

Shuhei Yahiro

Tomoyuki Ariyoshi

Provided is a toner binder which combines excellent low-temperature fixing properties and excellent hot-offset resistance (namely which permits a wide fixing-temperature range) and which exhibits excellent storage stability. The toner binder comprises (A) a polyester resin, (B) a specific crystalline resin and, if necessary, (C) a non-crystalline linear polyester resin. The polyester resin (A) comprises a carboxylic acid component (x) and a polyol component (y) as the essential constituent units, said component (x) comprising two or more kinds of dicarboxylic acids (x1) selected from among aromatic dicarboxylic acids and ester-forming derivatives thereof in a total amount of 80 mol % or more and further containing an at least trivalent polycarboxylic acid (x2) as another essential component, and said component (y) comprising a C2-10 aliphatic diol (y1) in an amount of 50 mol % or more. Further, the polyester resin (A) exhibits a storage modulus at 150&#xb0; C. [G'(150)] of 2000 Pa or more, and the [G&#x2032;(150)] and [G&#x2032;(180)] (storage modulus at 180&#xb0; C.) of the resin (A) satisfy a specific relationship.

Toner binder and toner composition

Disclosed are core-shell resin particles (C2) each comprising one or more film-like shell layers (P) comprising a resin (a) which is a polyurethane resin and a core layer (Q) comprising a resin (b). A core-shell resin particle (C2) is characterized in that the weight ratio between (P) and (Q) is from 0.1:99.9 to 70:30, the volatile content in the resin particle (C2) is not more than 2 weight %, and the content of vinyl resins in the resin (b) is not more than 30 weight %. Such resin particles have a uniform particle diameter and are excellent in electrostatic properties, thermal and storage stability and thermal characteristics.

Resin dispersion and resin particle

Disclosed is a heat-fusible electrostatic image developing toner which has an excellent balance between fixability at low temperatures and grindability and is excellent in glossiness after fixing. Also disclosed is a resin for toners. A polyester resin for toners which is obtained by polycondensing a polyol component and a polycarboxylic acid component is characterized by containing 20-100 weight % of one or more polyester resins (A1) having a storage elastic modulus from 2.5 x 10Pa to 5 x 10Pa at 150&#xb0; C. wherein the molar average cohesive energy of the polyol component is between 7.0 x 10and 1.4 x 10J.

Polyester resin for toner, toner composition and resin particle

Disclosed is a heat-fusible electrostatic image developing toner which has an excellent balance between fixability at low temperatures and grindability and is excellent in glossiness after fixing. Also disclosed is a resin for toners. A polyester resin for toners which is obtained by polycondensing a polyol component and a polycarboxylic acid component is characterized by containing 20-100 weight % of one or more polyester resins (A1) having a storage elastic modulus from 2.5&#xd7;10Pa to 5&#xd7;10Pa at 150&#xb0; C. wherein the molar average cohesive energy of the polyol component is between 7.0&#xd7;10and 1.4&#xd7;10J.

The present invention relates to core-shell resin particles (C2) each comprising one or more film-like shell layers (P) comprising a first resin (a) and a core layer (Q) comprising a second resin (b). The core-shell resin particle (C2) is characterized in that the weight ratio between (P) and (Q) is from 0.1:99.9 to 70:30, the volatile content in the resin particle (C2) is not more than 2 weight %, and the resin (a) has an initial softening temperature of 40 to 270&#xb0; C., a Tg of 20 to 250&#xb0; C., a flow temperature of 60 to 300&#xb0; C., and the difference of the Tg and the flow temperature in a range of 0 to 120&#xb0; C. The resin particles are excellent in electrostatic property, thermal storage stability and thermal properties, and exhibit a narrow particle diameter distribution.

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Kyoto, Japan

Takashi Akutagawa