TWI873348B - Color wax - Google Patents

Abstract

The present invention provides a toner wax, which can impart low-temperature fixability to the toner, exhibits excellent storage stability in the toner, and can contribute to the high image quality of toner prints by improving the color development of the toner. The toner wax is characterized in that it is composed of an ester compound, wherein the molar percentage Amol% of the constituent component derived from (A) pentaerythritol is 19.0-25.0mol%, the molar percentage Bmol% of the constituent component derived from (B) a linear saturated fatty acid having 14-24 carbon atoms is 55.0-80.5mol%, and the molar percentage Cmol% of the constituent component derived from (C) adipic acid is 0.50-20.0mol%.

Description

Color wax

The present invention relates to a toner wax which is suitable for use as a toner in a recording method for developing an electrostatic charge image such as an electrophotographic method or an electrostatic recording method in an image forming apparatus such as a photocopier or a laser printer.

The toner used in image forming devices such as copiers and printers contains a colorant (carbon black, magnetic powder, pigment, etc.), a charge regulator, and wax in a thermoplastic resin as a binder resin, and further contains a fluidity additive, a cleaning aid, and a transfer aid as needed.

Among them, wax has the function of preventing toner from remaining on the fixing roller during fixing (filming) and promoting the softening of thermoplastic resin to improve the fixing property. In recent years, due to the increase in environmental awareness around the world, the low-temperature fixing property of toner has been paid attention to in order to reduce power consumption. Wax has a low melting point, and it is intended to improve the low-temperature fixing property of toner by lowering the melting temperature of thermoplastic resin.

On the other hand, excessive wax seepage on the surface of the molten toner may cause the toner to adhere to fixing components such as the fixing roller or the fixing belt, which may result in poor image quality. In addition, wax seepage during storage of the toner may become a major cause of adhesion of toner particles to each other. Therefore, research has been conducted on improving the storage stability of the toner by using a high molecular weight synthetic multifunctional ester wax that is less likely to seep during storage of the toner.

Furthermore, in recent years, with the popularization of print on demand digital printing in the commercial printing field, printed materials with high-resolution image output and unprecedented metallic style printed materials have appeared. As the demand for colorants with good color rendering properties increases, a material that helps high color rendering is sought.

For example, Patent Document 1 discloses a toner using a multifunctional polyester wax obtained from pentaerythritol, a fatty acid having 11 to 30 carbon atoms, and a fatty acid having 1 to 10 carbon atoms. It is described that these multifunctional polyester waxes have excellent low-temperature fixability and storage stability. However, when the wax of Patent Document 1 is used, the color development of the toner cannot be improved.

Furthermore, Patent Document 2 describes a method for producing an ester wax for a toner, wherein a linear saturated monocarboxylic acid selected from carbon atoms of 14 to 30 or a mixture thereof, and a linear saturated monohydric alcohol selected from carbon atoms of 14 to 30 or a mixture thereof, or a divalent to hexavalent polyhydric alcohol selected from carbon atoms of 2 to 30 or a mixture thereof, are subjected to a condensation reaction, followed by neutralization with an alkaline aqueous solution, and the neutralization salt is removed by centrifugal separation. Patent Document 2 also describes that by using the wax, a toner having excellent low-temperature fixability and storage stability can be provided. However, when the wax of Patent Document 2 is used, the color development of the toner cannot be improved.

Prior art documents Patent documents Patent document 1: Japanese Patent Publication No. 7-98511 Patent document 2: Japanese Patent Publication No. 2012-32479

Technical Problems to be Solved by the Invention

The purpose of the present invention is to provide a colorant wax which can impart low-temperature fixability to the colorant and exhibit excellent storage stability in the colorant, and can contribute to the high-quality image of the colorant print by improving the color development of the colorant. Technical means for solving technical problems

The inventors of the present invention have conducted intensive studies to solve the above-mentioned technical problems, and as a result, have found that when an ester compound containing a component derived from (A) pentaerythritol, a component derived from (B) a linear saturated fatty acid having 14 to 24 carbon atoms, and a component derived from (C) adipic acid in a specific ratio is used as a toner wax, it is possible to impart low-temperature fixing properties to the toner, exhibit excellent storage stability in the toner, and contribute to high-quality image printing of toner prints by improving the color development properties of the toner, thereby completing the present invention.

That is, the wax composition for coloring agent of the present invention is characterized in that it is composed of an ester compound, wherein the molar percentage Amol% of the constituent component derived from (A) pentaerythritol is 19.0-25.0mol%, the molar percentage Bmol% of the constituent component derived from (B) a linear saturated fatty acid having 14-24 carbon atoms is 55.0-80.5mol%, and the molar percentage Cmol% of the constituent component derived from (C) adipic acid is 0.50-20.0mol%. Effect of the invention

The toner wax of the present invention achieves the following effects: it can impart low-temperature fixability to the toner, exhibits excellent storage stability in the toner, and contributes to high-quality toner prints by improving the color development of the toner.

The following is an explanation of the implementation of the present invention. In addition, in this specification, the numerical range specified by the symbol "~" includes the numerical values at both ends (upper limit and lower limit) of the "~". For example, "2~5" means 2 or more and 5 or less.

The toner wax of the present invention is an ester compound containing (A) a constituent derived from pentaerythritol as an alcohol component, (B) a constituent derived from a linear saturated fatty acid having 14 to 24 carbon atoms as a first acid component, and (C) a constituent derived from adipic acid as a second acid component.

It is believed that when an ester compound containing a component derived from (A) pentaerythritol, a component derived from (B) a linear saturated fatty acid having 14 to 24 carbon atoms, and a component derived from (C) adipic acid in a specific ratio is used as a toner wax, the compatibility with the binder resin is appropriately improved and the compatibility with the colorant is also improved.

It is believed that since the compatibility of the wax with the binder resin is appropriately increased, the toner can be given low-temperature fixability by lowering the softening temperature of the resin, and it is not easy to seep into the toner, thus showing excellent storage stability. In addition, it is believed that since the compatibility of the wax with the colorant is also high, it does not hinder the dispersion of the colorant, and the color development of the toner is improved. And it is believed that while having low-temperature fixability and storage stability, by improving the color development of the toner, it contributes to the high image quality of toner prints.

As the raw material derived from the constituent components of (A) pentaerythritol as the alcohol component, pentaerythritol or a pentaerythritol derivative which can give the same structural unit as pentaerythritol in the ester synthesis reaction can be used.

Since pentaerythritol is a neopentyl polyol having a neopentyl skeleton, it has excellent oxidation stability and heat resistance. As other neopentyl polyols, neopentyl glycol, trihydroxymethylpropane, and dipentaerythritol can be listed. However, when neopentyl glycol and trihydroxymethylpropane are used as alcohol components, there is a possibility that the melting point of the obtained ester is significantly lowered and the storage stability in the toner is deteriorated. When dipentaerythritol is used as the alcohol component, there is a possibility that the viscosity is significantly increased and the low-temperature fixability is insufficient. Therefore, the neopentyl polyol used in the present invention is preferably pentaerythritol.

As the raw material of the constituent component derived from (B) a linear saturated fatty acid having 14 to 24 carbon atoms as the first acid component, a linear saturated fatty acid having 14 to 24 carbon atoms or a fatty acid derivative that can give the same structural unit as a linear saturated fatty acid having 14 to 24 carbon atoms in an ester synthesis reaction can be used.

As the linear saturated fatty acid having 14 to 24 carbon atoms used in the present invention, for example, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoic acid, etc. can be listed. In the present invention, a mixed carboxylic acid containing two or more of these monovalent linear saturated carboxylic acids can be used. Among the above linear saturated fatty acids, palmitic acid, stearic acid, arachidic acid, behenic acid are preferred, and stearic acid, arachidic acid, behenic acid are particularly preferred.

When the number of carbon atoms is less than 14, the melting point may decrease and the storage stability in the toner may deteriorate. On the other hand, when the number of carbon atoms is more than 24, the low-temperature fixing property may not be sufficiently imparted.

As the raw material derived from the constituent component of (C) adipic acid as the second acid component, adipic acid which is a dicarboxylic acid or an adipic acid derivative which can give the same structural unit as that of adipic acid in an ester synthesis reaction can be used.

When succinic acid or the like having less carbon atoms than adipic acid is used as the dicarboxylic acid, the heat resistance may be significantly deteriorated. In addition, when sebacic acid or the like having more carbon atoms than adipic acid is used, the melting point may be significantly lowered, and the storage stability in the toner may be deteriorated.

The toner wax of the present invention is composed of an ester compound, wherein the molar percentage Amol% of the constituent component derived from (A) pentaerythritol is 19.0-25.0mol%, the molar percentage Bmol% of the constituent component derived from (B) a linear saturated fatty acid having 14-24 carbon atoms is 55.0-80.5mol%, and the molar percentage Cmol% of the constituent component derived from (C) adipic acid is 0.50-20.0mol%. When the content ratio of each of the components (A), (B) and (C) is outside the above range, the low-temperature fixing property and storage stability of the toner may become insufficient, and the effect of improving the color development property of the toner cannot be obtained.

From the above perspectives, the molar percentage Amol% of the constituents from (A) pentaerythritol is preferably 20.0-24.0mol%, and further preferably 20.5-22.5mol%. In addition, the molar percentage Bmol% of the constituents from (B) straight chain saturated fatty acids having 14-24 carbon atoms is preferably 57.5-78.5mol%, and further preferably 60.0-77.5mol%. In addition, the molar percentage Cmol% of the constituents from (C) adipic acid is preferably 1.5-19.0mol%, and further preferably 2.0-17.5mol%.

The above-mentioned molar percentages A mol %, B mol %, and C mol % are values calculated by analyzing the ester compound by ¹ H-NMR and determining the molar amounts of the constituent components derived from the respective raw materials.

The measurement conditions of ¹ H-NMR are shown below.

<Measurement conditions> ·Analytical instrument: ¹ H-NMR (400MHz) ·Solvent: deuterated chloroform

The molar amount can be determined by analyzing the 1H-NMR chart of the ester compound obtained under the above measurement conditions. Specifically, the following four peaks are used. ·Peak (I): 3.40~3.70ppm = (A) Hydrogen α-position of unreacted hydroxyl group of pentaerythritol ·Peak (II): 4.00~4.20ppm = (A) Hydrogen α-position of reacted hydroxyl group of pentaerythritol {Peak (I) and Peak (II) total 8} ·Peak (III): 0.85~0.90ppm = Hydrogen bonded to the terminal carbon of (B) straight chain saturated fatty acid with 14~24 carbon atoms (3) ·Peak (IV): 2.25~2.35ppm = (C) Hydrogen α-position of carbonyl group of adipic acid (4) and (B) Hydrogen α-position of carbonyl group of straight chain fatty acid with 14~22 carbon atoms (2)

The integral values of the above four peaks are calculated as the molar amounts Amol, Bmol, and Cmol of each component from each raw material in the following manner. Amol={integral value of peak (I)+integral value of peak (II)}/8 Bmol=integral value of peak (III)/3 Cmol={integral value of peak (IV)-(Bmol×2)}/4

The molar percentages Amol%, Bmol%, and Cmol% are calculated from the molar amounts Amol, Bmol, and Cmol obtained above in the following manner: Amol%=100×Amol/(Amol+Bmol+Cmol) Bmol%=100×Bmol/(Amol+Bmol+Cmol) Cmol%=100×Cmol/(Amol+Bmol+Cmol)

The molecular weight of the ester compound in the present invention can be measured by gel permeation chromatography (GPC). The molecular weight of the ester compound in the present invention is preferably in the range of 2000 to 3500 based on the number average molecular weight of the monodisperse polystyrene conversion of the polyester compound. Within this number average molecular weight range, both the imparting of low-temperature fixability and the excellent storage stability of the toner can be taken into account.

From the viewpoint of storage stability, the acid value of the ester compound in the present invention is preferably 5 mgKOH/g or less, more preferably 3 mgKOH/g or less, and particularly preferably 1 mgKOH/g or less.

Furthermore, from the viewpoint of storage stability, the hydroxyl value is preferably 20 mgKOH/g or less, more preferably 15 mgKOH/g or less, and particularly preferably 10 mgKOH/g or less.

In addition, the acid value can be measured according to JOCS (Japan Oil Chemical Society) 2.3.1-1996, and the hydroxyl value can be measured according to JOCS (Japan Oil Chemical Society) 2.3.6.2-1996.

The ester compound of the present invention can lower the softening temperature of the resin, thereby providing the toner with low-temperature fixability, and can provide the toner with excellent storage stability due to its large molecular weight and high viscosity.

The melting point of the ester compound in the present invention is preferably 60 to 90° C., more preferably 65 to 85° C. If the melting point is lower than 60° C., the storage stability is deteriorated, and if the melting point is higher than 90° C., low-temperature fixability cannot be imparted to the toner.

The melting point of the ester can be measured by differential scanning calorimetry (DSC) at a heating rate of 10°C per minute, and the temperature of the top peak of the endothermic peak measured by DSC analysis can be taken as the melting point.

As a method for producing the ester compound in the present invention, for example, there can be cited a production method utilizing the following reactions: a dehydration condensation reaction of pentaerythritol as an alcohol component raw material and a linear saturated fatty acid having 14 to 24 carbon atoms and adipic acid as an acid component raw material, a reaction of pentaerythritol with acid halides of a linear saturated fatty acid having 14 to 24 carbon atoms and adipic acid, an ester exchange reaction of a first ester containing pentaerythritol as an alcohol component and a second ester containing a linear saturated fatty acid having 14 to 24 carbon atoms and adipic acid as an acid component, and the like.

A catalyst may be used in the reaction. Examples of the catalyst include acidic and alkaline catalysts, such as zinc acetate, titanium compounds, p-toluenesulfonic acid, and methanesulfonic acid.

After the esterification reaction is completed, the obtained reaction product can be highly purified by recrystallization, distillation, solvent extraction, etc.

The toner wax of the present invention is mixed with a binder resin, a colorant, a charge modifier, etc., and the toner is manufactured by a conventional method. The amount of the toner wax of the present invention mixed in the toner is preferably 0.1 to 15 parts by mass relative to 100 parts by mass of the binder resin. The toner wax of the present invention may be mixed alone or in combination with two or more kinds.

The binder resin is not particularly limited, and a binder resin conventionally used as a toner can be used, for example, styrene resin, acrylate resin, styrene-acrylate copolymer resin, polyester resin, polyvinyl chloride resin, polyvinyl acetate resin, phenol resin, epoxy resin, etc. can be used.

In addition, the colorant is not particularly limited, and colorants that have been used as colorants in the past can be used, such as carbon black, magnetic powder, pigments of various colors, etc. Example

Next, the present invention is described in further detail by showing examples and comparative examples. 1. Preparation example of wax Table 1 shows the composition, acid value, hydroxyl value, number average molecular weight Mn and melting point of the colorant wax used in the examples and comparative examples. The preparation methods of the various waxes shown in Table 1 are as follows.

[Preparation of wax a]

In a 3L four-necked flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade and a cooling tube, 280g (2.06mol) of pentaerythritol, 119.9g (0.82mol) of adipic acid, 1955.2g (6.87mol) of stearic acid and 2.36g (0.01mol) of p-toluenesulfonic acid were added and reacted at 220°C under a nitrogen flow. The crude ester product obtained was 2215.5g and the acid value was 7.5mgKOH/g.

To the crude ester product, add 700 g of toluene and 150 g of 2-propanol, add a 10 mass% potassium hydroxide aqueous solution containing 2.0 equivalents of potassium hydroxide to the residual acid value of the crude ester product, and stir at 70°C for 30 minutes. Then, let it stand for 30 minutes, separate and remove the water layer (lower layer). Repeat the washing 4 times until the pH of the discharged water is neutral. Under the reduced pressure conditions of 180°C and 1 kPa, distill to remove the solvent of the residual ester layer, and filter to obtain 2060.4 g of wax a. The yield relative to the crude ester product for deacidification is 93%.

[Preparation of wax b]

In a 3L four-necked flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade and a cooling tube, 280g (2.06mol) of pentaerythritol, 119.9g (0.82mol) of adipic acid and 1955.2g (6.87mol) of stearic acid were added and reacted at 220°C under a nitrogen flow. The crude ester product obtained was 2211.8g and the acid value was 11.5mgKOH/g.

To the crude ester product, add 700 g of toluene and 150 g of 2-propanol, add a 10 mass% potassium hydroxide aqueous solution containing 2.0 equivalents of potassium hydroxide to the residual acid value of the crude ester product, and stir at 70°C for 30 minutes. Then, let it stand for 30 minutes, separate and remove the water layer (lower layer). Repeat the washing 4 times until the pH of the discharged water is neutral. Under the reduced pressure conditions of 180°C and 1 kPa, distill to remove the solvent of the residual ester layer, and filter to obtain 2057.5 g of wax b. The yield relative to the crude ester product for deacidification is 93%.

[Preparation of wax c~g and j~l]

Waxes c to g and j to l shown in Table 1 were obtained by the same steps except that the same raw materials as in the preparation of wax a were used and the amounts of raw materials added were changed.

[Preparation of wax]

Palmitic acid was used as the straight chain saturated fatty acid and wax h was obtained by the same preparation steps as wax a.

[Preparation of wax]

Wax i was obtained by using behenic acid as the straight chain saturated fatty acid and the same preparation steps as wax a.

[Preparation of Pentaerythritol Tetrastearate (PETS) Wax]

In a 3L four-necked flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade and a cooling tube, 280 g (2.06 mol) of pentaerythritol and 1955.2 g (6.87 mol) of stearic acid were added, and the mixture was reacted at 220° C. under a nitrogen flow. The crude ester product obtained was 2640.3 g, and the acid value was 8.7 mgKOH/g.

Add 750 g of toluene and 200 g of 2-propanol to the crude ester product, add a 10 mass% potassium hydroxide aqueous solution containing 2.0 times the equivalent of potassium hydroxide to the residual acid value of the crude ester product, and stir at 70°C for 30 minutes. Then, let it stand for 30 minutes, separate and remove the water layer (lower layer). Repeat the washing 4 times until the pH of the discharged water is neutral. Under the reduced pressure conditions of 180°C and 1 kPa, distill to remove the solvent of the residual ester layer, and filter to obtain 2520.7 g of PETS wax. The yield relative to the crude ester product for deacidification is 95%.

[Table 1] Manufacturing example a b c d e f g h i Molar percentage of constituents from (A) Amol% 22.0 23.0 20.4 20.1 24.3 19.7 23.7 22.4 21.4 Molar percentage of constituents from (B) Bmol% 69.2 68.9 78.8 76.6 57.4 78.1 56.9 69.2 70.2 Molar percentage of constituents from (C) Cmol% 8.8 8.1 0.8 3.3 18.3 2.2 19.4 8.4 8.4 Types of Straight Chain Saturated Fatty Acids Stearic Acid C18 Palmitic Acid C16 Behenic acid C22 Acid value (mgKOH/g) 0.4 0.4 0.1 0.2 0.3 0.6 0.5 0.6 0.3 Hydroxyl value (mgKOH/g) 3.6 12.0 2.7 3.1 8.5 0.1 7.5 9.2 2.9 Number average molecular weight Mn 2800 2750 2160 2400 3250 2250 3600 2480 3150 DSC melting point℃ 68.4 67.3 79.6 71.8 66.5 73.8 61.0 63.8 85.5 Manufacturing example PETS j k l Molar percentage of constituents from (A) Amol% 20.5 15.4 27.0 24.5 Molar percentage of constituents from (B) Bmol% 79.5 84.0 55.8 53.6 Molar percentage of constituents from (C) Cmol% 0.0 0.6 17.2 21.9 Types of Straight Chain Saturated Fatty Acids Stearic Acid C18 Acid value (mgKOH/g) 0.1 33.5 0.8 0.2 Hydroxyl value (mgKOH/g) 4.1 1.4 42.0 4.1 Number average molecular weight Mn 1980 1985 3220 4875 DSC melting point℃ 82.5 70.1 57.8 46.8

2. Evaluation methods The various measurement and evaluation methods performed in the implementation examples and comparative examples are as follows.

2-1. Determination of wax composition and physical properties

(1) Molar percentage of each component in wax Amol%, Bmol%, Cmol% 1H-NMR analysis was performed on each wax under the following measurement conditions, and the obtained 1H-NMR chart was analyzed to determine the molar amount of the component from each raw material. Based on the obtained molar amount, the molar percentage of each component in the wax Amol%, Bmol%, Cmol% was calculated using the above calculation formula. <Measurement conditions> ·Analytical instrument: 1H-NMR (400MHz) ·Solvent: deuterated chloroform

(2) Acid value of wax Measured according to JOCS (Japan Oil Chemical Society) 2.3.1-1996.

(3) Hydroxyl value of wax Measured in accordance with JOCS (Japan Oil Chemical Society) 2.3.6.2-1996.

(4) Number average molecular weight of wax HC-8320 GPC EcoSEC (manufactured by TOSOH CORPORATION) was used as a gel permeation chromatography (GPC) measuring device. THF was used as an eluent, the measuring temperature was set to 40°C, and polystyrene was used as a standard substance to measure the number average molecular weight of the wax.

(5) Melting point of wax A "DSC-7000X" manufactured by Hitachi High-Tech Science Corporation was used as a differential scanning calorimeter. About 10 mg of ester was added to the sample holder, 10 mg of aluminum oxide was used as a standard substance, and the temperature was raised from 30°C to 150°C at a rate of 10°C per minute. In addition, before the measurement, a sample that had undergone a heating process from 30°C to 150°C and a cooling process from 150°C to 30°C was used as a measurement sample. The temperature of the top peak of the endothermic peak measured by the above DSC was taken as the melting point of the wax.

2-2. Wax performance evaluation

(1) Effect of lowering the melting temperature of the resin The effect of lowering the melting temperature when wax is mixed in the adhesive resin was evaluated by the following method. Evaluation samples were prepared for Examples 1 to 9 and Comparative Examples 1 to 4. Specifically, 95 parts by mass of a polyester resin (product name: Diacron ER-508, manufactured by MITSUBISHI RAYON CO., LTD.) and 5 parts by mass of the wax shown in Table 2 were mixed and melt-kneaded using a double-screw mixer "LABO PLASTOMILL" (manufactured by TOYOSEKI) to obtain a resin mixture. The melt kneading was carried out at 120°C and 80 rpm/min for about 5 minutes, and the obtained resin kneaded product was crushed and molded into particles of 100 μm or less as evaluation samples. In addition, the resin kneaded product containing polyester resin but no wax was crushed and molded into particles of 100 μm or less as blank samples. For these evaluation samples and blank samples, 1 g of the sample was molded into a cylinder with a diameter of 1 cm × a height of 1 cm, and the 1/2 melting temperature was measured using a rheometer (CFT-500EX: manufactured by Shimadzu Corporation) at a heating rate of 2°C/min and a load of 20 kg. For each sample, three measurements were performed and the average value was calculated to obtain the measurement average value T of each evaluation sample and the measurement average value Tblank of the blank sample. The 1/2 melting temperature (1/2T) is calculated by the following calculation formula (1) using the measured average value T of the evaluation sample and the measured average value Tblank of the blank sample. The larger the value of the 1/2 melting temperature calculated in this way, the better the low-temperature fixing property is evaluated to be. Calculation formula (1): 1/2T = Tblank - T

(2) Storage stability in resin The storage stability of the adhesive resin when wax is mixed was evaluated by the following method. In order to evaluate the storage stability in the resin, the evaluation samples of Examples 1 to 9 and Comparative Examples 1 to 4 prepared in the evaluation of the effect of lowering the melting temperature of the resin were used. For these evaluation samples, 5 g of the resin mixture as the evaluation sample was placed in a glass vial, and the mixture was left to stand in a thermostatic chamber maintained at 45°C for 2 weeks. The glass vial was inverted, and when the sample was taken out without applying force, the quality of the sample that did not settle in the vial but flowed out and whose particle size was maintained at 100 μm or less was set as X. At this time, the anti-blocking rate R was calculated by the following calculation formula (2). Calculation formula (2): R = X(g)/5(g) For the calculated anti-adhesion rate R, refer to the following evaluation criteria to evaluate the storage stability. The larger the value of the calculated anti-adhesion rate R, the better the storage stability is evaluated. In addition, the values shown in the brackets of Table 2 are the values of the calculated anti-adhesion rate R. <Evaluation criteria> ○ (excellent): 0.85 ≤ anti-adhesion rate R △ (good): 0.75 < anti-adhesion rate R < 0.85 × (poor): 0.75 ≥ anti-adhesion rate R

(3) Color development improvement effect The color development improvement effect of the wax was evaluated by the following method. Evaluation samples were prepared for Examples 1 to 9 and Comparative Examples 1 to 4. Specifically, 94 parts by mass of a polyester resin (product name: Diacron ER-508, manufactured by MITSUBISHI RAYON CO., LTD.), 5 parts by mass of the wax shown in Table 2, and 1 part by mass of a colorant (product name: PV-FAST BLUE BG, manufactured by Clariant) were mixed and melt-kneaded using a double-screw mixer (product name: "LABO PLASTOMILL", manufactured by TOYO SEKI CO., LTD.) to obtain a resin mixture. The melt kneading was carried out at 120°C and 80 rpm/min for about 5 minutes, and the obtained resin kneaded product was molded into a smooth plate (100×100 mm) by a hot press as an evaluation sample. In addition, a smooth plate-shaped molded product containing 99 parts by mass of polyester resin and 1 part by mass of coloring agent but no wax was prepared as a blank sample. For these evaluation samples, a colorimeter (colorimeter ZE6000, manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the sample surface in the reflection mode to obtain the color a ^* and b ^* values of each hue in the CIE1976 (L ^* , a ^* , b ^* ) color space (the so-called CIELAB). Using the measured values, the chroma C of the evaluation sample is calculated using the following calculation formula (3). For the blank sample, the colorimeter is also used to measure in the same way to calculate the chroma C blank of the blank sample. Calculation formula (3): C = (a ^{* 2} + b ^{* 2} ) ^1/2 Using the values of the chroma C of the evaluation sample and the chroma C blank of the blank sample, the color rendering improvement rate Kc is calculated using the following calculation formula (4). The larger the value of the color rendering improvement rate Kc calculated in this way, the better the color rendering improvement effect is evaluated. Calculation formula (4): Kc = C / C blank

3. Evaluation results

Regarding the above Examples and Comparative Examples, the composition and physical properties of the wax itself are shown in Table 1, and the composition of the samples used in the performance evaluation of the wax as a toner material and the results of the performance evaluation are shown in Table 2.

[Table 2]

The melting points of the waxes a to i used in Examples 1 to 9 are in the range of 60°C to 90°C. By lowering the melting temperature of the resin, the toner can be given low-temperature fixability, and the anti-blocking rate R is also high, so the storage stability in the toner during storage is also excellent. Furthermore, since the color development improvement rate Kc is Kc>1, the color development of the toner can be improved.

On the other hand, in Comparative Example 1, in which the molar percentage Cmol% of the constituent component derived from adipic acid was 0mol%, that is, pentaerythritol tetrastearate (PETS) monomer was used, the 1/2 melting temperature was lower than that of the Example, and thus the toner could not be sufficiently provided with low-temperature fixability. Furthermore, the color development improvement rate Kc was Kc<1, and when used as a toner wax, there was no effect of improving the color development.

For Comparative Example 2 using wax j in which the molar percentage Bmol% of the constituent components from a linear saturated acid is higher than the range of the present invention, compared with the embodiment, the anti-blocking rate R is low, the storage stability in the colorant is deteriorated, and the color development improvement rate Kc is Kc＜1, and there is no effect of improving the color development.

In Comparative Example 3 using wax k in which the molar percentage A mol % of the constituent component derived from pentaerythritol was higher than the range of the present invention, the anti-blocking ratio R was low and the storage stability was poor.

In Comparative Example 4, in which wax 1 in which the molar percentage C mol % of the constituent component derived from adipic acid was higher than the range of the present invention, the anti-blocking rate R was low and the storage stability was deteriorated.

without.

without.

without.

Claims (1)

A wax for a toner is characterized in that it is composed of an ester compound, wherein the molar percentage Amol% of a component derived from (A) pentaerythritol is 19.0-25.0mol%, the molar percentage Bmol% of a component derived from (B) a linear saturated fatty acid having 14-24 carbon atoms is 55.0-80.5mol%, and the molar percentage Cmol% of a component derived from (C) adipic acid is 0.50-20.0mol%.