Toner binder and toner

Patent metadata

Field	Value
Publication number	US-2016159976-A1
Application number	US-201414906756-A
Country	US
Kind code	A1
Filing date	Jul 22, 2014
Priority date	Jul 23, 2013
Publication date	Jun 9, 2016
Grant date	—

Abstract

A toner binder comprising a polyester, the end of which is partially esterified with a monocarboxylic acid and/or a monohydric alcohol, the polyhydric alcohol component of which comprises a C 3 alkylene glycol (a21) and an aromatic-ring-bearing diol (a22) at an (a21)/(a22) molar ratio of 5/95 to 70/30, and which has an ester group concentration of 16 to 30 wt % and satisfies a specific relationship between the ester group concentration and the hydroxy value. The toner binder combines low-temperature fixability and storage stability under high-temperature conditions or heat-temperature and -humidity conditions, and exhibits excellent durability.

First claim

1 . A toner binder comprising a polyester resin (A) having, as constitutional units, a polycarboxylic acid (a1) as a polycarboxylic acid component and a polyhydric alcohol (a2) as a polyhydric alcohol component and having been esterified with a monocarboxylic acid (a3) and/or a monohydric alcohol (a4) at a part of the terminals thereof, wherein the ester group concentration of (A) based on the weight of (A) is 16 to 30% by weight, the polyhydric alcohol (a2) comprises an alkylene glycol (a21) having three carbon atoms and a diol (a22) having an aromatic ring, the molar ratio of (a21) to (a22) is (a21)/(a22)=5/95 to 70/30, and (A) fulfills the following condition 1:
229×(ECON)+90×(OHV)≦12,000   [Condition 1]

wherein (ECON) denotes a value representing the ester group concentration of (A) expressed by the unit of % by weight, and (OHV) denotes a value representing the hydroxy value of (A) expressed by the unit of mgKOH/g.

2 . The toner binder according to claim 1 , wherein the polyester resin (A) is a polyester resin esterified at a part of the terminals thereof with the monocarboxylic acid (a3) and the monocarboxylic acid (a3) is an aromatic monocarboxylic acid (a31).

3 . The toner binder according to claim 1 , wherein the acid value of the polyester resin (A) is 40 mgKOH/g or less, and the amount of water in (A) after storing (A) under conditions of 40° C. and a relative humidity of 80% for 20 hours is 12,000 ppm or less based on the weight of (A).

4 . The toner binder according to claim 1 , wherein the absolute value of the difference between a ½ falling temperature (T1) and a ½ falling temperature (T0) is 8° C. or less as measured with a flow tester at a temperature ramp-up rate of 6° C./min and a load of 1.96 MPa, wherein the ½ falling temperature (T1) is a temperature at which half of a measurement sample of the polyester resin (A) flows out during extrusion of 1 g of the measured resin (A) through a nozzle having a diameter of 1 mm and a length of 1 mm after subjecting the (A) to storage under conditions of 40° C. and a relative humidity of 80% for 20 hours, and the ½ falling temperature (T0) is a temperature measured for (A) before the storage under conditions of 40° C. and a relative humidity of 80% for 20 hours.

5 . The toner binder according to claim 1 , wherein the diol (a22) having an aromatic ring is an alkylene oxide adduct of bisphenol A.

6 . The toner binder according to claim 2 , wherein the aromatic monocarboxylic acid (a31) is benzoic acid.

7 . The toner binder according to claim 1 , wherein the glass transition temperature of the polyester resin (A) is 40 to 80° C.

8 . The toner binder according to claim 1 , wherein the hydroxy value of the polyester resin (A) is 30 mgKOH/g or less.

9 . The toner binder according to claim 1 , wherein the number average molecular weight of the polyester resin (A) is 500 to 4000.

10 . A toner comprising the toner binder according to claim 1 , a colorant, and a mold release agent.

Assignees

• Sanyo Chemical Ind Ltd

Inventors

• Ono Takashi
• Sugiyama Kazuki
• Bando Takaaki
• Ota Yasuaki
• Tanaka Takahiro
• Yamashita Taiji
• Kawaguchi Kakuhiro

Classifications

• C08G63/668

  derived from polycarboxylic acids and polyhydroxy compounds · CPC title

• G03G9/08797

  characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature · CPC title

• G03G9/08795

  characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants · CPC title

• G03G9/08755

  Polyesters · CPC title

• C08G63/46 Primary

  Polyesters chemically modified by esterification (C08G63/20 takes precedence; by after-treatment C08G63/91) · CPC title