JP2010271469A - Method for producing polyester resin, polyester resin for toner, and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin which contains a raw material component derived from a plant and provides a toner having good fixability, hot offset resistance, and storage stability, and which has little environmental load; and to provide a toner using the same. <P>SOLUTION: A method for producing the polyester resin includes polycondensating polyhydric alcohols comprising an aromatic diol and 1,3-propanediol derived from a plant raw material, and polyvalent polycarboxylic acids containing trivalent or higher carboxylic acids in an amount of 0.5-20 mol% based on all acidic components. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyester resin, in particular, a method for producing a polyester resin for toner that is suitably used for developing an electrostatic charge image or a magnetic latent image in electrophotography, electrostatic recording method, electrostatic printing method, etc., polyester resin for toner, And toner.

  In the method of obtaining an image by the electrophotographic printing method and the electrostatic charge developing method, the electrostatic charge image formed on the photoreceptor is developed with toner charged in advance by friction and then fixed. As for the fixing method, there are a heat roller method in which a toner image obtained by development is fixed using a pressurized and heated roller, and a non-contact fixing method in which fixing is performed using an electric oven or flash beam light. In order to pass through these processes without any problem, the toner needs to maintain a stable charge amount first, and then needs to have good fixability to paper. In addition, the apparatus has a fixing unit which is a heating body, and the temperature in the apparatus rises, so that it is necessary that the toner does not block. Further, even during continuous printing, it is necessary that the apparatus is not soiled or fogged on the printing surface, that is, the durability of the toner is required.

  Further, in the heat roller system, the temperature of the fixing unit has been lowered from the viewpoint of energy saving, and the toner has been strongly required to have a capability of fixing onto a paper at a lower temperature, that is, a low temperature fixability. In addition, devices are becoming more compact and rollers that do not apply oil have been used, and there is an increasing demand for toner to be peelable from the heat roller, that is, non-offset.

  Binder resin for toner has a great influence on the toner characteristics as described above, and polystyrene resin, styrene acrylic resin, polyester resin, epoxy resin, polyamide resin, etc. are known, but recently, toughness, A polyester resin which is excellent in fixability at a low temperature and has a good performance balance has attracted particular attention.

 For example, Patent Document 1 describes that 1,3-propanediol is used as an essential component as means for improving non-offset property and low-temperature fixability in a polyester resin for toner.

  On the other hand, in recent years, carbon neutral has attracted particular attention from the viewpoint of environmental protection such as the prevention of global warming, and the transition from conventional plastics derived from petroleum materials to plastics derived from plant materials with less environmental impact has been actively promoted. ing.

  For example, the Japan Bioplastics Association has certified plastic products with a ratio of 25% by weight or more of biomass-derived components in the biomass plastic composition contained in raw materials and products as “biomass plastics”. Authorized for use.

  The use of plant-derived components in the toner is also desired for the toner, and the binder resin constituting the toner is also desired to contain a constituent unit derived from a plant raw material.

As a polyester resin containing a plant-derived component, for example, Patent Document 2 describes a method for producing a polyester in which a polycarboxylic acid derived from a plant raw material and a diol are polycondensed.
JP 2002-169331 A JP 2007-197654 A

  However, in Patent Document 1, there is a description of 1,3-propanediol and aromatic diol, 1,3-propanediol and trivalent or higher carboxylic acid in combination and polycondensation, but 1,3-propanediol, There is no description of polycondensation using an aromatic diol and a trivalent or higher carboxylic acid in combination, and since no aromatic diol and 1,3-propanediol are used in combination, hot offset resistance, especially an oil-free fixing roller is used. The hot offset resistance was insufficient.

  Furthermore, there is no description of using raw materials derived from plant raw materials, and environmental load reduction is not considered.

  Further, Patent Document 2 does not describe the use of a polyester resin composed of a plant-derived constituent component for toner use, but a description of using 1,3-propanediol, aromatic diol and trivalent or higher carboxylic acid in combination as constituent components. Even when used as a toner, the storage stability and hot offset resistance were insufficient.

  The gist of the present invention is that a polyhydric alcohol containing an aromatic diol and a plant raw material-derived 1,3-propanediol, and a polyhydric alcohol containing 0.5 to 20 mol% of a trivalent or higher carboxylic acid with respect to the total acid component. In the method for producing a polyester resin in which polyvalent carboxylic acid is polycondensed.

  By using the polyester resin for toner of the present invention, it is possible to provide a toner having a low environmental load and good fixability, hot offset resistance and storage stability.

  In the present invention, a polyhydric alcohol containing an aromatic diol and a plant raw material-derived 1,3-propanediol and a polycarboxylic acid containing 0.5 to 20 mol% of a trivalent or higher carboxylic acid with respect to the total acid component. The acid is polycondensed.

  By including an aromatic diol component as the polyhydric alcohol, the storage stability when the toner is formed is improved.

  As the aromatic diol component, polyoxypropylene- (2.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) ) Propane, polyoxypropylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxypropylene- (2.4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis 4-hydroxyphenyl) propane and the like, can be used alone or in combination of two or more.

  The content of the aromatic diol is preferably 3 mol parts or more and 100 mol parts or less with respect to 100 mol parts of the total acid component. When the content of the aromatic diol is 3 mol parts or more with respect to 100 mol parts of the total acid component, the storage stability and charging stability as a toner tend to be good. Further, when the content of the aromatic diol is 100 mol parts or less with respect to 100 mol parts of the total acid components, the reaction rate tends to be improved and the toner fixing property tends to be improved.

  Furthermore, in the present invention, it is necessary to contain 1,3-propanediol derived from plant raw materials as a polyhydric alcohol. By including 1,3-propanediol, hot offset resistance and low-temperature fixability are improved.

  Plant raw material-derived 1,3-propanediol can be obtained using corn starch or the like as a raw material, and examples thereof include Susterra (registered trademark) propanediol (DuPont Co., Ltd.).

  Moreover, it is preferable that content of 1, 3- propanediol derived from a plant raw material is contained 20 mass% or more with respect to all the structural components from a viewpoint of environmental impact reduction.

  Further, in the present invention, as a polyhydric alcohol, for example, ethylene glycol, neopentyl glycol, polyethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, as long as the effects of the present invention are not impaired. , Diethylene glycol, triethylene glycol, aliphatic diols such as 1,4-cyclohexanedimethanol, etc., sorbitol, 1,2,3,6-hexatetralol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripenta Erythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol, trimethylol Propane, 1,3,5- It can be used trivalent or higher alcohol component, such as Li-hydroxymethyl benzene. Among these, pentaerythritol and trimethylolpropane are preferable.

  These may be plant-derived substances or petroleum-derived substances, and may be used alone or in combination of two or more.

  Furthermore, in this invention, it is necessary to contain 0.5-20 mol% carboxylic acid more than trivalence with respect to all the acid components as polyhydric carboxylic acid.

  When the trivalent or higher carboxylic acid is less than 0.5 mol%, the hot offset resistance of the toner is insufficient, and when it exceeds 20 mol%, the storage stability of the toner is insufficient.

  The trivalent or higher carboxylic acid component is not particularly limited, but trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalene. Examples thereof include tricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid, and esters or acid anhydrides thereof. In these, trimellitic acid or its anhydride is preferable.

  Further, as the polyvalent carboxylic acid, for example, divalent carboxylic acids such as terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, or esters thereof Or an aromatic dicarboxylic acid component such as an acid anhydride, aliphatic such as phthalic acid, sebacic acid, isodecyl succinic acid, dodecenyl succinic acid, maleic acid, fumaric acid, adipic acid, succinic acid, or esters or acid anhydrides thereof A dicarboxylic acid component etc. are mentioned, It can use individually or in combination of 2 or more types. These may be plant-derived substances or petroleum-derived substances.

  Moreover, as a bivalent carboxylic acid component, it is preferable that 80-99.5 mol% of aromatic dicarboxylic acid components are included with respect to all the acid components. When the content of the aromatic dicarboxylic acid component is 80 mol% or more, the storage stability of the toner tends to be good or the resin strength tends to improve. When the content is 99.5 mol% or less, the toner As a result, the hot offset resistance tends to be good. The lower limit of the content of the aromatic dicarboxylic acid is more preferably 85 mol% or more, and the upper limit is more preferably 99 mol% or less.

  In the present invention, polycondensation of the polyhydric alcohol and polycarboxylic acid is performed.

The method of polycondensation is not particularly limited. For example, there is a method in which the polyhydric alcohol and the polycarboxylic acid are introduced into a reaction vessel and polymerized through an esterification reaction or a transesterification reaction, and a condensation polymerization reaction. In the polymerization of the polyester resin mentioned, for example, a polymerization catalyst such as titanium tetraalkoxide, titanium oxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium oxide, magnesium acetate can be used. .

  The polymerization temperature is not particularly limited, but is preferably in the range of 180 ° C to 280 ° C. When the polymerization temperature is 180 ° C. or higher, the productivity tends to be good, and when it is 280 ° C. or lower, the decomposition of the resin and the by-product of volatile components that cause odor tend to be suppressed. The lower limit of the polymerization temperature is more preferably 200 ° C. or higher, and particularly preferably 220 ° C. or higher. The upper limit of the polymerization temperature is more preferably 270 ° C. or less.

  In the present invention, if necessary, a polyester resin can be polymerized by adding a release agent component together with the above components within a range not impairing the effects of the present invention. By adding a release agent component and polymerizing, the toner fixing property and wax dispersibility tend to be improved. As the release agent component, the same waxes that can be used as a toner formulation described later can be used as appropriate, for example, carnauba wax, rice wax, beeswax, synthetic ester wax, paraffin wax, various polyolefin waxes or modified products thereof, Examples thereof include fatty acid amides and silicone waxes.

  The polyester resin obtained by the production method of the present invention preferably has a Tg of 48 ° C to 75 ° C. When Tg is 48 ° C. or higher, toner storage stability tends to be good, and when it is 75 ° C. or lower, toner fixability tends to be good. The lower limit value of Tg is more preferably 50 ° C. or higher, and the upper limit value is more preferably 72 ° C. or lower.

  The softening temperature of the polyester resin is preferably 110 to 160 ° C. When the softening temperature is 110 ° C. or higher, the hot offset resistance of the toner tends to be good, and when it is 160 ° C. or lower, the toner fixability tends to be good.

  Furthermore, the acid value of the polyester resin is preferably 2 to 25 mgKOH / g. When the acid value is 2 mgKOH / g or more, the reactivity of the resin tends to be improved, and when the acid value is 25 mgKOH / g or less, the toner image density tends to be stable. The upper limit of the acid value of the polyester resin is more preferably 20 mgKOH / g or less, and particularly preferably 15 mgKOH / g or less.

Next, a toner using the polyester resin will be described.
The toner of the present invention is obtained by blending a colorant, a charge control agent, a release agent, an additive such as a flow modifier, a magnetic material, and the like.

  The colorant is not particularly limited, but carbon black, nigrosine, aniline blue, phthalocyanine blue, phthalocyanine green, hansa yellow, rhodamine dye, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo And disazo dyes, condensed azo dyes or pigments. These dyes and pigments can be used alone or in admixture of two or more. In the case of a full-color toner, benzidine yellow, monoazo dyes and condensed azo dyes are used as yellow, quinacridone, rhodamine dyes, and monoazo dyes are used as magenta, and phthalocyanine blue is used as cyan. The content of the colorant is not particularly limited, but is preferably 2 to 10% by mass in the toner from the viewpoint of toner color tone, image density, and thermal characteristics.

  The charge control agent is not particularly limited, and examples of the positive charge control agent include quaternary ammonium salts and basic or electron-donating organic substances. Negative charge control agents include metal chelates, metal-containing dyes, and acidic substances. Or an electron withdrawing organic substance etc. are mentioned. In the case of color toners, it is important that the charge control agent is colorless to light color and does not impair the color tone of the toner. For example, metal salts, metal complexes, amides of salicylic acid or alkylsalicylic acid with chromium, zinc, aluminum, etc. A compound, a phenol compound, a naphthol compound, etc. are mentioned. Furthermore, a vinyl polymer having a styrene, acrylic acid, methacrylic acid or sulfonic acid group may be used as the charge control agent.

  The content of the charge control agent is not particularly limited, but is preferably 0.5 to 5% by mass in the toner. When the content of the charge control agent is 0.5% by mass or more, the charge amount of the toner tends to be a sufficient level, and when the content is 5% by mass or less, a decrease in the charge amount due to aggregation of the charge control agent is suppressed. It tends to be.

  The release agent is not particularly limited, and carnauba wax, rice wax, beeswax, polypropylene wax, polyethylene wax, synthetic ester type in consideration of toner releasability, storage stability, fixability, color developability, etc. Wax, paraffin wax, fatty acid amide, silicone wax and the like can be appropriately selected and used. These can be used alone or in combination of two or more.

  The melting point of the release agent is not particularly limited, and can be appropriately selected and used in consideration of the toner performance. The content of the release agent is not particularly limited, but is preferably 0.3 to 15% by mass in the toner because it affects the toner performance. The lower limit of the content of the release agent is more preferably 1% by mass or more, and particularly preferably 2% by mass or more. Further, the upper limit value of the content of the release agent is more preferably 13% by mass or less, and particularly preferably 12% by mass or less.

  Additives such as flow modifiers are not particularly limited, but fine powder silica, alumina, titania and other fluidity improvers, magnetite, ferrite, cerium oxide, strontium titanate, conductive titania and other inorganic fine powders , Resistance adjusting agents such as styrene resin and acrylic resin, lubricants and the like, and these are used as an internal additive or an external additive.

  The content of these additives is not particularly limited, but is preferably 0.05 to 10% by mass in the toner. When the content of these additives is 0.05% by mass or more, a toner performance-modifying effect tends to be sufficiently obtained, and when it is 10% by mass or less, the image stability of the toner tends to be good. is there.

  Further, as the binder resin, a binder resin other than the polyester resin of the present invention may be used. For example, a polyester resin other than the polyester resin of the present invention, a styrene-based resin, a styrene-acrylic resin, a cyclic olefin resin, a methacrylic acid-based resin. A resin, an epoxy resin, etc. can be mentioned, In the range which does not impair the effect of this invention, it can use individually or in mixture of 2 or more types.

  The toner of the present invention can be used as any one of a magnetic one-component developer, a non-magnetic one-component developer, and a two-component developer.

  When used as a magnetic one-component developer, it contains a magnetic substance. Examples of the magnetic substance include ferromagnetic alloys including iron, cobalt, nickel, etc., including ferrite, magnetite, etc. Alloys that do not contain magnetic elements but exhibit ferromagnetism by appropriate heat treatment, such as so-called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, and chromium dioxide Is mentioned.

  The content of the magnetic substance is not particularly limited, but is preferably 3 to 70% by mass in the toner because it greatly affects the pulverizability of the toner. When the content of the magnetic material is 3% by mass or more, the charge amount of the toner tends to be at a sufficient level, and when it is 70% by mass or less, the fixability and grindability of the toner tend to be good. The lower limit of the content of the magnetic substance is more preferably 3% by mass or more, and particularly preferably 3% by mass or more. Further, the upper limit of the content of the magnetic material is more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

  When used as a two-component developer, it is used in combination with a carrier. As the carrier, a known material such as a magnetic substance such as iron powder, magnetite powder, or ferrite powder, a resin coating on the surface thereof, or a magnetic carrier can be used. As coating resins for resin coating carriers, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, mixtures of these resins, etc. Can be used.

  The method for producing the toner of the present invention is not particularly limited, but after mixing the binder resin and the compound described above, the mixture is melt-kneaded with a twin screw extruder or the like, coarsely pulverized, finely pulverized, and classified. A method of manufacturing by externally adding inorganic particles (grinding method), dissolving and dispersing the binder resin and compound described above in a solvent, granulating in an aqueous medium, removing the solvent, washing, Examples thereof include a method (chemical method) in which toner particles are obtained by drying and externally added with inorganic particles as necessary.

  Although the Example of this invention is shown below, the embodiment of this invention is not limited to this. The evaluation methods for the resin and toner shown in this example are as follows.

(1) Evaluation method of polyester resin (Glass transition temperature (Tg))
Intersection of the base line on the low temperature side of the chart and the tangent line of the endothermic curve near the glass transition temperature when measured with a differential scanning calorimeter DSC-60 manufactured by Shimadzu Corporation at a heating rate of 5 ° C / min The temperature of was determined.

(Softening temperature)
When using a flow tester CFT-500 manufactured by Shimadzu Corporation and measuring with a 1 mmφ × 10 mm nozzle under a constant temperature increase with a load of 294 N (30 Kgf) and a temperature increase rate of 3 ° C./min, The temperature at which 1/2 of the effluent flowed was determined.

(Acid value)
About 0.2 g of the sample was precisely weighed in a branch Erlenmeyer flask (A (g)), 10 ml of benzyl alcohol was added, and the mixture was heated in a nitrogen atmosphere for 15 minutes with a heater at 230 ° C. to dissolve the resin. After cooling to room temperature, 10 ml of benzyl alcohol, 20 ml of chloroform and a few drops of a phenolphthalein solution were added and titrated with a 0.02N KOH solution (titrate = B (ml), titer of KOH solution = p). . A blank measurement was performed in the same manner (titer amount = C (ml)), and calculation was performed according to the following formula.
Acid value (mgKOH / g) = (BC) × 0.02 × 56.11 × p ÷ A
(2) Toner evaluation method (Storage stability)
About 5 g of the toner was weighed and put into a sample bottle, which was left in a drier kept at 45 ° C. for about 24 hours, and the degree of toner aggregation was evaluated as an index of blocking resistance. The evaluation criteria were as follows.
◎ (Very good): Disperse just by inverting the sample bottle.
○ (Good): Disperse when the sample bottle is turned upside down and hit 2-3 times.
△ (available): Disperse when the sample bottle is inverted and tapped 4-5 times.
X (Inferior): The sample bottle is inverted and does not disperse when tapped 5 times.

(Fixability)
^3. Using a printer having a fixing roller not coated with silicone oil and capable of changing the roller temperature with the roller speed set to 100 mm / s, the test pattern has a vertical toner density of 0.5 mg / cm ² . A solid image of 5 cm × 15 cm wide was prepared, and the fixing roller was set at a temperature of 160 ° C. and fixed. With respect to this test pattern image, three locations were set as evaluation points, and the image density was measured and recorded with a Macbeth image densitometer. The density measurement part is vertically valley-folded, a 1 kg weight is slid 5 times on the folded part from the top of the protective paper, and then the mountain is folded at the same fold, and the protective paper is placed on the folded part from the top. The weight was slid 5 times.

The test paper was stretched, a cellophane tape (Nitto Denko CS System No. 29) was applied to the bent portion, traced 5 times, and then slowly peeled off. The image density was measured with a Macbeth image densitometer. The same test was conducted at three locations, and the respective fixing rates were calculated from the image density before and after the test by the following formula, and evaluated according to the following criteria based on the average fixing rates at the three locations.
Fixing rate = image density after test / image density before test × 100 (%)
◎ (very good): fixing rate of 85% or more ○ (good): fixing rate of 80% or more and less than 85% Δ (available): fixing rate of 75% or more and less than 80% × (poor): less than 75% Fixation rate or offset phenomenon occurs at 160 ° C and cannot be measured (Hot offset resistance)
Using a printer that has a fixing roller not coated with silicone oil and that can change the roller temperature set at a roller speed of 30 mm / s, the test pattern has a toner concentration of 0.5 mg / cm ^{2 and} a length of 4.5 cm. × When printing a solid image of 15 cm wide at a roller temperature of 5 ° C, the minimum temperature when the toner moves to the fixing roller due to the hot offset phenomenon at the time of fixing is defined as the hot offset generation temperature. The offset property was judged.
◎ (Very good): Hot offset generation temperature is 200 ° C or higher ○ (Good): Hot offset generation temperature is 180 ° C or higher and lower than 200 ° C △ (available): Hot offset generation temperature is 170 ° C or higher and lower than 180 ° C x ( Inferior): Hot offset occurrence temperature is less than 170 ° C. (Example 1)
1500 ppm of antimony trioxide with respect to the acid component, alcohol component, and all acid components shown in Table 1 was charged into a reaction vessel equipped with a distillation column. In addition, the preparation composition described in Table 1 is a mole part of each component with respect to 100 mole parts of the total acid component.

  Subsequently, the rotation speed of the stirring blade in the reaction vessel was kept at 120 rpm, temperature increase was started, and the temperature in the reaction system was heated to 265 ° C., and this temperature was maintained. After the esterification reaction is completed and water is no longer distilled from the reaction system, the temperature in the reaction system is lowered and maintained at 235 ° C., the pressure in the reaction vessel is reduced over about 40 minutes, and the degree of vacuum is set to 133 Pa. The condensation reaction was conducted while distilling the diol component from the reaction system.

  The viscosity of the reaction system increased with the reaction, the degree of vacuum was increased with the increase of the viscosity, and the condensation reaction was carried out until the torque of the stirring blade reached a value indicating a desired softening temperature. And stirring was stopped when the predetermined torque was shown, the reaction system was returned to normal pressure, and the reaction product was taken out by pressurizing with nitrogen to obtain a polyester resin. The characteristic values of the obtained polyester resin are shown in Table 1.

  Next, the polyester resin obtained above was used to form a toner. For blending the toner, 93 parts by mass of polyester resin, 3 parts by mass of quinacridone pigment (HOSTAPARM PIN E, CI No .: Pigment Red 122 manufactured by Clariant), 3 parts by mass of Carnauba Wax No. 1 (manufactured by Toyo Adre) Part, 1 part by mass of a negatively chargeable charge control agent (LR-147 manufactured by Nippon Carlit) was mixed for 5 minutes with a Henschel mixer.

  Next, the obtained mixture was melt-kneaded with a biaxial kneader. The melt kneading was performed by setting the internal temperature to the softening temperature of the resin. After kneading, the toner soul was obtained by cooling, finely pulverized to 10 μm or less with a jet mill fine pulverizer, and fine particles of 3 μm or less were cut with a classifier to adjust the particle size. To 100 parts by mass of the obtained fine powder, 0.25 part by mass of silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) was added and mixed by a Henschel mixer to obtain a toner.

The obtained toner was evaluated for toner using the aforementioned evaluation method. The evaluation results are shown in Table 1.
Examples 2-5, Comparative Examples 1-3
A polyester resin was obtained in the same manner as in Example 1 except that the acid component and the alcohol component were changed as shown in Table 1. The characteristic values of the obtained polyester resin are shown in Table 1.

  Next, a toner was obtained in the same manner as in Example 1 using the obtained polyester resin. The obtained toner was evaluated for toner using the aforementioned evaluation method. The evaluation results are shown in Table 1.

Diol A: Polyoxypropylene- (2.3) -2,2-bis (4-hydroxyphenyl) propanediol 1,3-propanediol: Susterra (registered trademark) propanediol (DuPont)
Since Comparative Example 1 did not contain an aromatic diol, the storage stability of the toner was poor.

  Since Comparative Example 2 did not contain a trivalent or higher carboxylic acid, the hot offset resistance of the toner was poor.

  In Comparative Example 3, the storage stability of the toner was poor because the amount of trivalent or higher carboxylic acid exceeded 20 mol% with respect to the total acid component.

Claims (4)

Polycondensation of polyhydric alcohol containing aromatic diol and plant raw material-derived 1,3-propanediol and polyhydric carboxylic acid containing 0.5-20 mol% of trivalent or higher carboxylic acid with respect to the total acid component A method for producing a polyester resin. A polyester resin for toner obtained by the production method according to claim 1. The polyester resin for toner according to claim 2, which has a glass transition temperature of 48 ° C. to 75 ° C. A toner containing the polyester resin for toner according to claim 2.