Wax melting accelerator and wax composition containing same

Abstract

To provide a wax melting accelerating agent that can improve the melting speed of wax without changing the melting point of wax by adding a small amount to wax, and to provide a wax composition that contains the same.SOLUTION: Provided are a wax melting accelerating agent that comprises an ester compound represented by the following formula (I), and a wax composition that contains the wax melting accelerating agent in a proportion of a mass ratio (wax: wax melting accelerating agent) of 99.99: 0.01 to 99:1. In the following formula (I), R1 is CH3(CH2)5C(O)(CH2)10-, R2 is CH3(CH2)5CH(OH)(CH2)10-, A is a glycerin residue, and x represents an integer of 1 or more and 3 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a wax melting accelerator and a wax composition containing the same. More specifically, the present invention relates to a wax melting accelerator that can increase the melting rate of wax without changing the melting point of the wax by adding a small amount of the accelerator to the wax, and a wax composition containing the accelerator. [Background technology]

[0002] Waxes generally include materials such as waxy solid esters and paraffin waxes. The former are synthetic ester waxes made from animal and vegetable oils, higher fatty acids, and higher fatty acids and higher alcohols, while the latter are waxy alkanes with approximately 20 or more carbon atoms obtained by refining petroleum. Waxes are used as additives to improve the functionality of various materials because they exhibit lubricity, water resistance, plasticity, and gloss. For example, they are added to toners as release agents, to hot-melt inks to control viscosity, and are used in heat-sensitive valves by utilizing their melting from solid to liquid. Waxes are also used in the cosmetics field as gelling agents, scrubbing agents, and blocking agents. As described above, waxes are used in a wide variety of applications, but they are particularly well suited for applications that utilize the phase change due to the wax's unique thermal response to impart a temperature-sensitive function.

[0003] With the rapid development of technology in various fields in recent years, there is a need to improve the performance of materials to which these waxes are added, and even of the wax itself. In particular, when the wax is used in applications that utilize the phase change caused by the thermal response, such as when the wax is used as a release agent for toner, there is a demand for wax that can melt quickly when it reaches a specific temperature.

[0004] For example, Patent Document 1 introduces a wax composition that can maintain the offset resistance of a toner even during high-speed printing, in which a high-melting hydrocarbon wax is blended with a low-melting ester wax.

[0005] In addition, Patent Document 2 proposes a sharp-melting ester wax as a means for imparting excellent low-temperature fixing properties to a toner and suppressing the generation of sublimates that cause environmental pollution even when instantaneously exposed to high heat. When such a wax is used, it is possible to precisely control the melting temperature of the wax and improve the temperature sensitivity at the target temperature.

[0006] In the past, in order to meet such needs for toner, attempts have been made to increase the melting speed of wax by using wax with a low melting point or a wax with a sharp melting property.

[0007] However, when a wax with a low melting point is used or when a wax with an even lower melting point is blended with a main wax, the wax may melt at a temperature lower than the target temperature. In addition, when a wax with a low melting point is used, the durability of the printed matter may be reduced compared to when a hydrocarbon wax is used alone, and the storage stability of the toner may be deteriorated in a hot and humid environment, which may impair other functions of the toner. Furthermore, when a sharp-melt wax is used, it is possible to precisely control the melting temperature of the wax and improve the temperature sensitivity at the target temperature, but this does not necessarily increase the melting speed of the wax or contribute to high-speed printing.

[0008] Furthermore, the need for a wax that melts quickly at a specific temperature is not limited to toner release agents. For example, Patent Document 3 proposes a thermostat device that uses paraffin wax as a thermoelement, and discloses that it functions as a heat-sensitive valve that adjusts the flow rate of fluid by utilizing the volume change caused by melting from solid to liquid and thermal expansion and contraction of each phase, when combined with a valve body of a piston rod. Such devices are used in engine cooling systems for automobiles, and in sports cars and the like, there is a demand for technology that can switch cooling on and off at ultra-high speeds when the engine temperature reaches a specified temperature. Furthermore, wax is used in the cosmetic field for scrubs, balms, lipsticks, etc. For example, Patent Document 4 proposes a lipstick composition using ceresin wax or microcrystalline wax as a lipstick composition with excellent storage stability. In this way, when wax is used to improve storage stability, there is a concern that it will not melt quickly when used, impairing the feeling of use. Therefore, there is a demand for a technology that improves the temperature sensitivity of wax and allows it to melt quickly when used.

[0009] Under these circumstances, there is a demand for a melting accelerator that can increase the melting rate of wax without changing the melting point of the wax. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2014-182348 A [Patent Document 2] JP 2002-212142 A [Patent Document 3] JP 2017-101583 A [Patent Document 4] Japanese Patent Application Publication No. 10-152413 Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a wax melting accelerator which, when added in a small amount to a wax, can improve the melting rate of the wax without changing the melting point of the wax, and a wax composition containing the same. [Means for solving the problem]

[0012] Means for Solving the Problems The present inventors conducted intensive research in view of the above problems and discovered that it is possible to improve the melting rate of a wax without changing the melting point of the wax by adding a small amount of an ester compound represented by the following formula (I) to the wax, thereby completing the present invention. That is, the present invention is as follows.

[0013] [1] A wax melting promoter comprising an ester compound represented by the following formula (I):

[0014] [ka]

[0015] [In the formula (I), R 1 is CH3(CH2)5C(O)(CH2) 10 - and R 2 is CH3(CH2)5CH(OH)(CH2) 10 - and A is a glycerol residue, x is the R 1 represents the number of ester residues having the formula:

[0016] [2] A wax composition comprising the wax melting accelerator according to [1] above and a wax, wherein the mass ratio of the wax to the wax melting accelerator (wax:wax melting accelerator) is in the range of 99.99:0.01 to 99:1. Effect of the Invention

[0017] According to the wax melting accelerator of the present invention, by adding the wax melting accelerator to the wax so that the mass ratio (wax:wax melting accelerator) is in the range of 99.99:0.01 to 99:1, it is possible to promote melting of the wax while maintaining the melting point of the wax. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The wax melting accelerator of the present invention is used by adding it to a wax. For example, a wax composition can be produced by adding the wax melting accelerator of the present invention to a wax, heating and melting the wax at a temperature equal to or higher than the melting point thereof, and mixing the wax uniformly. Hereinafter, an embodiment of the present invention will be described. In this specification, a numerical range defined using the symbol "~" is intended to include both the upper and lower limits of the range. For example, "2~5" means "2 or more and 5 or less."

[0019] [Wax melting accelerator] The wax melting promoter of the present invention comprises an ester compound represented by formula (I).

[0020] [ka]

[0021] [In the formula (I), R 1 is CH3(CH2)5C(O)(CH2) 10 - and R 2 is CH3(CH2)5CH(OH)(CH2) 10 - and A is a glycerol residue, x is the R 1 represents the number of ester residues having the formula:

[0022] The method for synthesizing the ester compound represented by formula (I) is not particularly limited, and the compound may be synthesized by a method known per se or a method equivalent thereto. For example, the compound may be obtained by esterifying glycerin with 12-hydroxystearic acid and 12-oxostearic acid using a protecting group, followed by deprotection and purification.

[0023] The protecting group is not particularly limited, and for example, by protecting the hydroxyl groups at the 1- and 2-positions of glycerin with an acetal group, it becomes possible to react the fatty acid regioselectively. In addition, an acetyl group, a p-toluenesulfonylcarbato group, a trityl group, a t-butyl group, etc. can be used to protect the hydroxyl group of 12-hydroxystearic acid, but it is preferable to use a p-toluenesulfonylcarbato group, etc., which can be deprotected under mild conditions without breaking the ester bond with glycerin. The p-toluenesulfonylcarbaminate group is an alcohol protecting group generated by reacting an alcoholic hydroxyl group with tosyl isocyanate (p-toluenesulfonyl isocyanate).

[0024] The esterification reaction can be carried out under various conditions, but can be carried out according to a general procedure for esterification reaction, without a catalyst or using a protonic acid catalyst or a Lewis acid catalyst such as hydrochloric acid, sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, or an acidic ion exchange resin. Furthermore, a deacidification step using an alkaline aqueous solution or a purification treatment such as an adsorption treatment may be carried out as appropriate.

[0025] The ester compound represented by formula (I) preferably has an acid value of 3.0 mgKOH / g or less and a hydroxyl value of 125.0 mgKOH / g or less. More preferably, the acid value is 1.0 mgKOH / g or less and the hydroxyl value is 60.0 to 120.0 mgKOH / g. When the ester compound represented by formula (I) has an acid value of 3.0 mgKOH / g or less and a hydroxyl value of 125.0 mgKOH / g or less, the effects of the present invention are easily obtained, which is preferable. The lower limit of the acid value of the ester compound represented by formula (I) is usually 0.01 mg KOH / g. The lower limit of the hydroxyl value of the ester compound represented by formula (I) is usually 0.1 mg KOH / g. The acid value can be measured in accordance with JOCS (Japan Oil Chemists' Society) 2.3.1-96, and the hydroxyl value can be measured in accordance with JOCS (Japan Oil Chemists' Society) 2.3.6.2-96. The value of x in formula (I) can be calculated from formula (II) using the hydroxyl value of the ester compound represented by formula (I) and the hydroxyl value of 179 mgKOH / g calculated from the theoretical molecular weight of tri-12-hydroxystearic acid glyceride. x = 3 - {hydroxyl value of formula (I) ÷ 179 × 3} (II)

[0026] 〔wax〕 The wax used in the wax melting accelerator of the present invention is not particularly limited, but from the viewpoint of the stability of the wax during storage and the thermal responsiveness during use, it is preferably a waxy compound that melts at a transparent melting point of 50 to 120°C, more preferably 60 to 110°C, and even more preferably 70 to 100°C, and examples thereof include paraffin wax, ester wax, and amide wax. The transparent melting point can be measured in accordance with JOCS (Japan Oil Chemists' Society) 2.2.4.1 or JIS K-0064 (Japanese Industrial Standards) (method of measuring melting point by measuring light transmittance). The wax melting accelerator of the present invention is preferably a wax melting accelerator for at least one type of wax selected from the group consisting of paraffin wax, ester wax, and amide wax, and more preferably a wax melting accelerator for ester wax.

[0027] As a type of wax for which the wax melting accelerator of the present invention can be suitably used, ester wax will be described. The ester wax is not particularly limited as long as it is a fatty acid ester wax of a fatty acid and an alcohol, and examples thereof include natural waxes such as carnauba wax and castor wax, and synthetic waxes obtained by dehydration condensation reaction of a fatty acid and an alcohol. The constituent fatty acids of these waxes preferably have 16 to 22 carbon atoms, and more preferably have 18 to 22 carbon atoms. Among these, stearic acid (18 carbon atoms), 12-hydroxystearic acid (18 carbon atoms), and behenic acid (22 carbon atoms) are particularly preferred. As the alcohol that forms an ester bond with the fatty acid, a monohydric to hexahydric saturated aliphatic alcohol is preferred. Specific examples of the ester wax include behenyl behenate, tri-12-hydroxystearic acid glyceride, pentaerythritol tetrabehenate, and dipentaerythritol hexastearate.

[0028] The method for producing the fatty acid ester wax may be, for example, a method utilizing a dehydration condensation reaction between the monovalent linear saturated fatty acid and the alcohol. A catalyst may be used to efficiently proceed with the reaction. The reaction temperature is preferably 180 to 250°C, and the reaction may be carried out under reduced pressure. After the reaction, the wax may be purified by deacidification, washing with water, or the like. A commercially available fatty acid ester wax may be used.

[0029] The ester wax may be used alone or in combination of two or more kinds. In addition, fatty acid ester waxes synthesized using mixed fatty acids obtained from beef tallow, coconut oil, castor oil, palm oil, etc. as monovalent straight-chain saturated fatty acids may also be used.

[0030] [Wax Composition] The wax composition of the present invention contains a wax melting promoter consisting of an ester compound represented by the above formula (I) and a wax.

[0031] In the wax composition of the present invention, the mass ratio of the wax melting accelerator of the present invention (i.e., the wax melting accelerator consisting of the ester compound represented by formula (I)) to the wax is in the range of 99.99:0.01 to 99:1, preferably 99.9:0.1 to 99:1, as the mass ratio represented by "wax:wax melting accelerator". If the amount of the wax melting agent added exceeds 1.0 part by mass relative to 100 parts by mass of the total of the wax melting accelerator and the wax, the effect on the melting point of the wax increases. For example, when the wax composition obtained from the wax melting accelerator and the wax of the present invention is used as a wax for toner, the melting point may be lowered, causing a loss of storage stability, the hardness of the wax may be reduced, and the durability of the printed matter may be deteriorated. In addition, if the amount of the wax melting agent added is less than 0.01 part by mass relative to 100 parts by mass of the total of the wax melting accelerator and the wax, the melting speed of the wax may not be sufficiently improved.

[0032] In the present invention, the effect of adding a wax melting accelerator to a wax (i.e., the effect of improving the melting rate of the wax) can be evaluated, for example, by measuring the melting rates of the wax alone and the wax composition in which the wax melting accelerator is added to the wax alone, and calculating the rate of change (RM) from the melting rate of the wax alone to the melting rate of the wax composition. Specifically, the melting rate change ratio (RM) of the wax composition can be determined by the following procedure. First, a differential scanning calorimetry (DSC, Hitachi High-Tech Science Corporation's DSC-7000X) is used to measure the DSC in accordance with JIS K-7121 by placing 10 mg of a sample (wax composition or wax alone) on a sample dish and covering it with a lid. The sample is heated from 30°C to 200°C at a heating rate of 30°C / min in a nitrogen atmosphere. From the obtained DSC curve, the melting onset (Pim) and melting end point (Pem) of the sample are identified. The melting onset and end points (Pim, Pem) are defined as follows: Pim: Intersection of the extension of the baseline on the low temperature side of the melting peak and the tangent at the maximum slope point of the low temperature peak during the temperature rise Pem: Intersection of the extended baseline of the melting peak on the high temperature side and the tangent at the maximum gradient point of the peak on the high temperature side during the temperature rise Next, when the time required for the wax composition to reach Pim from Pem is mt and the time required for the wax alone to reach Pem from Pim is mtb, the melting rate change rate (RM) of the wax composition can be calculated using the following formula (1). Melting rate change rate (RM)% = (mtb-mt) / mt × 100 (1)

[0033] The wax melting accelerator of the present invention is preferably one which causes the melting rate change rate (RM) of the wax composition obtained by adding it to a wax to be 10% or more, more preferably 30% or more. The wax melting accelerator of the present invention is preferably one that does not change the transparent melting point of the wax composition obtained by adding it to a wax by 1° C. or more compared to the transparent melting point of the wax alone before the addition.

[0034] The wax composition of the present invention may contain other components such as an antioxidant and a dispersant as necessary, taking into consideration the application of the wax composition, within the range not impairing the effects of the present invention.

[0035] The wax composition of the present invention can be produced by a known method. For example, the wax composition can be produced by heating and melting the wax melting accelerator and the wax and mixing them uniformly. The heating temperature when the wax melting accelerator and the wax are heated and melted is usually 80 to 150°C.

[0036] The mode of use of the wax composition of the present invention is not particularly limited, but for example, the wax composition of the present invention can be blended in a toner. When the wax composition of the present invention is blended in a toner, it is generally blended together with a binder resin, a colorant, an external additive, a charge control agent, etc., and the toner can be manufactured by a conventional manufacturing method. The blending amount of the wax composition of the present invention in the toner is usually 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin blended in the toner. EXAMPLES

[0037] The present invention will be explained in more detail below by showing production examples of the wax melting accelerator of the present invention, but the present invention is not limited to the scope of these examples. In the following examples and comparative examples, "%" means by mass.

[0038] <Synthesis Example 1: Synthesis of wax melting promoter> The synthesis of a wax melting promoter consisting of an ester compound represented by formula (I) was carried out as follows.

[0039] [Protection of the hydroxy group of 12-hydroxystearic acid] Using a 2L four-neck flask equipped with a thermometer, nitrogen inlet tube, stirrer and cooling tube, 300g (1.00mol) of 12-hydroxystearic acid and 300g of tosyl isocyanate (1.48mol) were dissolved in 300mL of THF at 50°C under a nitrogen gas atmosphere and stirred for 12 hours. THF was distilled off under reduced pressure from the solution thus obtained. The concentrate thus obtained was dissolved in 150mL of toluene at 50°C, and separation treatment was performed three times using 150mL of ion-exchanged water, the toluene layer was collected, and the toluene was distilled off under reduced pressure for purification. The hydroxyl value of the obtained product was confirmed to be 0.1mgKOH / g or less, so it was confirmed that the hydroxyl group of 12-hydroxystearic acid was protected with a p-toluenesulfonylcarbamate group. The yield of 12-p-toluenesulfonylcarbamate stearic acid thus obtained was 450g (0.90mol), and the yield was 90%.

[0040] [Synthesis of 12-oxostearic acid] Using a 5L four-neck flask equipped with a thermometer, a dropping funnel, a stirrer and a cooling tube, 90g (0.30mol) of 12-hydroxystearic acid was added to 1800mL of 95% acetic acid and suspended at room temperature. 300mL of 8.0% aqueous sodium hypochlorite solution was slowly dropped into the flask using a dropping funnel under ice cooling. After the dropping was completed, the mixture was stirred at 10°C for 12 hours, and then 1500mL of ion-exchanged water was added and allowed to stand under ice cooling for 12 hours. The suspension was filtered to recover the residue, which was washed 10 times with 500mL of ion-exchanged water and dried in vacuum to obtain 12-oxostearic acid. The hydroxyl value of the obtained product was confirmed to be 0.1mgKOH / g or less, confirming that the hydroxyl group of 12-hydroxystearic acid was oxidized to obtain 12-oxostearic acid. The amount of 12-oxostearic acid thus obtained was 75 g (0.26 mol), and the yield was 86%.

[0041] [Synthesis of 12-oxostearic acid monoglyceride] 36g (0.27mol) of 1,2-isopropylidene glycol and 60g (0.20mol) of 12-oxostearic acid were added to a 500mL four-neck flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade and a cooling tube, and the mixture was reacted at 220°C under a nitrogen stream. The acid value of the crude ester compound after the reaction was 0.01mgKOH / g or less. After the temperature of the reaction system was lowered to 50°C, 100mL of acetic acid and 150mL of toluene were added and the mixture was stirred for 1 hour to perform deprotection, followed by separation and washing with 150mL of ion-exchanged water three times, and then the toluene was distilled off under reduced pressure to obtain 12-oxostearic acid monoglyceride. The yield was 64g (0.16mol), and the yield was 85%.

[0042] [Synthesis of wax melting promoter (A1)] 38g (0.10mol) of 12-oxostearic acid monoglyceride and 110g (0.22mol) of 12-p-toluenesulfonylcarbamate stearic acid were added to a 500mL four-neck flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and cooling tube, and reacted at 220℃ under a nitrogen stream. The acid value of the crude ester compound after the reaction was 5mgKOH / g. 30g of toluene and 20g of propanol were added to the crude ester product, and then a 10% aqueous potassium hydroxide solution containing potassium hydroxide in an amount equivalent to 2.0 times the residual acid value of the crude ester product was added, and the mixture was stirred at 70℃ for 30 minutes. The mixture was then left to stand for 30 minutes, and the aqueous layer (lower layer) was separated and removed. The mixture was washed with water four times until the pH of the wastewater became neutral. The solvent in the remaining ester layer was distilled off at 180° C. under reduced pressure of 1 kPa, and the residue was filtered to obtain 84 g (0.09 mol) of the wax melting promoter (A1) of the present invention in a yield of 90%. The resulting wax melting accelerator (A1) had an acid value of 0.03 mg KOH / g, a hydroxyl value of 119.2 mg KOH / g and a transparent melting point of 89°C. From the hydroxyl value of the wax melting accelerator (A1), the group R 1 The number x of ester residues having the formula (I), i.e., the amount of 12-oxostearic acid residues introduced, was determined to be x=1.

[0043] [Synthesis of wax melting promoter (A2)] In a 500mL four-neck flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade, and a cooling tube, 31g (0.33mol) of glycerin and 305g (1.02mol) of 12-oxostearic acid were added and reacted at 220°C under a nitrogen stream. The acid value of the crude ester compound after the reaction was 5mgKOH / g. After adding 60g of toluene and 30g of propanol to this crude ester product, a 10% aqueous potassium hydroxide solution containing potassium hydroxide in an amount equivalent to 2.0 times the residual acid value of the crude ester product was added and stirred at 70°C for 30 minutes. After that, the mixture was left to stand for 30 minutes to separate and remove the aqueous layer (lower layer). The mixture was washed with water four times until the pH of the wastewater became neutral. The solvent of the remaining ester layer was distilled off under reduced pressure conditions of 180°C and 1kPa, and filtration was performed to obtain 330g (0.32mol) of the wax melting promoter (A2) of the present invention. The yield was 97%. The resulting wax melting accelerator (A2) had an acid value of 0.06 mg KOH / g, a hydroxyl value of 0.5 mg KOH / g and a transparent melting point of 94°C. From the hydroxyl value of the wax melting accelerator (A2), the group R 1 The number x of ester residues having the formula (I), i.e., the amount of 12-oxostearic acid residues introduced, was determined to be x=3.

[0044] [Synthesis of wax melting promoter (A3)] In a 500mL four-neck flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade, and a cooling tube, 31g (0.33mol) of glycerin and 500g (1.01mol) of 12-p-toluenesulfonylcarbamate stearic acid were added, and the mixture was reacted at 220°C under a nitrogen stream. The acid value of the crude ester compound after the reaction was 5mgKOH / g. 100g of toluene and 60g of propanol were added to the crude ester product, and then a 10% aqueous potassium hydroxide solution containing potassium hydroxide in an amount equivalent to 2.0 times the residual acid value of the crude ester product was added, and the mixture was stirred at 70°C for 30 minutes. The mixture was then left to stand for 30 minutes, and the aqueous layer (lower layer) was separated and removed. The mixture was washed with water four times until the pH of the wastewater became neutral. The solvent of the remaining ester layer was distilled off under reduced pressure conditions of 180°C and 1kPa, and filtration was performed to obtain 84g (0.30mol) of the wax melting promoter (A3) of the present invention. The yield was 90%. The obtained wax melting accelerator (A3) had an acid value of 0.04 mg KOH / g, a hydroxyl value of 178.0 mg KOH / g and a transparent melting point of 92°C. From the hydroxyl value of the wax melting accelerator (A3), the group R 1 The number x of ester residues having the formula (I), i.e., the amount of 12-oxostearic acid residues introduced, was determined to be x=0.

[0045] Table 1 shows the acid value, hydroxyl value and transparent melting point of the obtained wax melting accelerators (A1) to (A3). The acid value, hydroxyl value and transparent melting point of the wax melting accelerators (A1) to (A3) were measured by the method described in the following [Measurement Method].

[0046] [Table 1]

[0047] [Synthesis of Wax W1 (Pentaerythritol Tetrabehenate)] In a 2L four-neck flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and cooling tube, 260g (1.90mol) of pentaerythritol and 2732g (8.04mol) of behenic acid were added and reacted at 220℃ under a nitrogen stream. The obtained crude ester product weighed 2759g and had an acid value of 9.4mgKOH / g. 570g of toluene and 89g of 2-propanol were added to this crude ester product, and then a 10% aqueous potassium hydroxide solution containing potassium hydroxide in an amount equivalent to 2.0 times the residual acid value of the crude ester product was added and stirred at 70℃ for 30 minutes. The mixture was then left to stand for 30 minutes, and the aqueous layer (lower layer) was separated and removed. Washing with water was repeated four times until the pH of the wastewater became neutral. The solvent in the remaining ester layer was distilled off under reduced pressure conditions of 180°C and 1 kPa, and filtration was performed to obtain 2580 g (1.71 mol) of an ester wax (hereinafter referred to as "wax W1"). The yield of wax W1 relative to the crude ester product subjected to deacidification was 90%.

[0048] [Preparation of Wax W2 (Behenyl Behenate)] In a 2L four-neck flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and cooling tube, 324g (1.00mol) of behenyl alcohol and 357g (1.05mol) of behenic acid were added and reacted at 220℃ under a nitrogen stream. The obtained crude ester product weighed 645g and had an acid value of 9.4mgKOH / g. 200g of toluene and 100g of 2-propanol were added to this crude ester product, and then a 10% aqueous potassium hydroxide solution containing potassium hydroxide in an amount equivalent to 2.0 times the residual acid value of the crude ester product was added and stirred at 70℃ for 30 minutes. The mixture was then left to stand for 30 minutes, and the aqueous layer (lower layer) was separated and removed. Washing with water was repeated four times until the pH of the wastewater became neutral. The solvent in the remaining ester layer was distilled off under reduced pressure conditions of 180°C and 1 kPa, and filtration was performed to obtain 620 g (0.96 mol) of an ester wax (hereinafter referred to as "wax W2"). ​​The yield of wax W2 relative to the crude ester product subjected to deacidification was 96%.

[0049] The acid value, hydroxyl value and transparent melting point of waxes W1 and W2 are shown in Table 2. The acid value, hydroxyl value, transparent melting point and melt viscosity were measured by the methods described in the following [Measurement Methods].

[0050] [Table 2]

[0051] [Measurement method] In the present invention, the acid value, hydroxyl value, transparent melting point and penetration of the wax melting accelerator, wax, wax composition and the like were measured by the following methods. (1) Acid value: Compliant with JOCS (Japan Oil Chemists' Society) 2.3.1-96. (2) Hydroxyl value: Compliant with JOCS (Japan Oil Chemists' Society) 2.3.6.2-96. (3) Transparent melting point: Complies with JIS K-0064. Based on the measured transparent melting point, a difference between the transparent melting point of the wax composition and that of the wax alone was evaluated as follows: ⊚ if it was less than 0.5°C, ◯ if it was 0.5°C or more but less than 1°C, and × if it was 1°C or more.

[0052] (4) Melting rate change rate (RM) of wax composition: For each of the wax composition and the wax alone, a differential scanning calorimetry (DSC, Hitachi High-Tech Science Corporation's DSC-7000X) was used to perform DSC measurement in accordance with JIS K-7121 under the following conditions. 10 mg of a sample (wax composition or wax alone) was placed in a sample dish and covered with a lid. The sample was heated from 30°C to 200°C at a heating rate of 30°C / min in a nitrogen atmosphere, and the DSC measurement was performed. From the obtained DSC curve, the melting onset (Pim) and melting end point (Pem) of the sample were identified. The melting onset and end points (Pim, Pem) are defined as follows: Pim: Intersection of the extension of the baseline on the low temperature side of the melting peak and the tangent at the maximum slope point of the low temperature peak during the temperature rise Pem: Intersection of the extended baseline of the melting peak on the high temperature side and the tangent at the maximum gradient point of the peak on the high temperature side during the temperature rise Next, the time required for the wax composition to reach Pim to Pem (mt) and the time required for the wax alone to reach Pim to Pem (mtb) were substituted into the following calculation formula (1) to calculate the melting rate change rate (RM) of the wax composition. Melting rate change rate (RM)% = (mtb-mt) / mt × 100 (1)

[0053] The calculated melting rate change rate (RM) was used to evaluate the effect of the wax melting promoter in improving the wax melting rate against the following criteria. RM≦0%: × 0% <RM≦10%のもの:△ 10% <RM≦20%のもの:〇 20% <RMのもの:◎

[0054] <Preparation and Evaluation of Wax Composition> Example 1 0.03 g of wax melting promoter A1 and 99.97 g of wax (W1) were added to a 0.3 L separable flask equipped with a stirring blade and a nitrogen inlet tube, and stirred at 150°C for 1 hour under a nitrogen stream. After cooling, solidification, and pulverization, a wax composition was obtained (hereinafter referred to as "wax composition of Example 1"). The transparent melting point and melting rate change rate of the obtained wax composition of Example 1 were measured by the method described in the above [Measurement method].

[0055] (Examples 2 to 4, Comparative Examples 1 to 2) The wax melting accelerator and wax W1 were used in the combinations shown in Table 3, and wax compositions were obtained in the same manner as in Example 1 (hereinafter, each of these will be referred to as "wax composition of Example 2"). For each of the wax compositions obtained in Examples 2 to 4 and Comparative Examples 1 and 2, the transparent melting point and the rate of change in melting rate were measured by the method described in the above [Measurement method].

[0056] (Examples 5 to 6, Comparative Example 3) The wax melting accelerator and wax W2 were used in the combinations shown in Table 4, and wax compositions were obtained in the same manner as in Example 1 (hereinafter, each of these will be referred to as "wax composition of Example 5"). For each of the wax compositions obtained in Examples 5 to 6 and Comparative Example 3, the transparent melting point and the rate of change in melting rate were measured by the method described in the above [Measurement method].

[0057] The results are shown in Tables 3 and 4.

[0058] [Table 3]

[0059] [Table 4]

[0060] From the results of Tables 3 and 4, it was found that the wax compositions of Examples 1 to 6, which contain a predetermined amount of wax melting accelerator (A1) or (A2), have an improved melting rate evaluated by the rate of change in melting rate (RM) and have almost no change in the melting point of the wax. As a result, even when the wax composition is used as a toner wax and image formation is performed at a higher speed than before, it is possible to provide a stable high-quality image without deterioration of image quality or occurrence of printing errors. The blank wax containing no melting accelerator had a slower melting rate than the Examples. The wax compositions of Comparative Examples 1 and 3 contained more wax melting accelerator than the prescribed amount, resulting in a significant change in melting point. In addition, the melting characteristics inherent to the melting accelerator were strongly expressed, so the melting rate did not improve compared to the Examples. The wax composition of Comparative Example 2 contained a wax melting accelerator represented by the group R 1In this example, an ester compound having an introduction amount x of 0 of an ester residue having the formula: x=0, i.e., an ester compound having no 12-oxostearic acid residue and only 12-hydroxystearic acid residue, was used. When such an ester compound was added to the wax, the change in melting point of the wax composition increased, and the melting speed did not improve. [Industrial Applicability]

[0061] According to the wax melting accelerator of the present invention, by adding the wax melting accelerator to the wax in a mass ratio (wax:wax melting accelerator) in the range of 99.99:0.01 to 99:1, the melting speed and fluidity of the wax can be improved without changing the melting point of the wax, which is expected to improve the functions expressed by the thermal response of the wax.

Claims

1. A wax melting promoter for ester wax, comprising an ester compound represented by the following formula (I): 【Chemistry 1】 [In the formula (I), R １ is CH ３ (CH ２ ) ５ C(O)(CH ２ ) １０ - and R ２ is CH ３ (CH ２ ) ５ CH(OH)(CH ２ ) １０ - and A is a glycerol residue, x is the R １ represents the number of ester residues having the formula:

2. A wax composition comprising the wax melting accelerator according to claim 1 and an ester wax, wherein the mass ratio of the ester wax to the wax melting accelerator (ester wax: wax melting accelerator) is in the range of 99.99:0.01 to 99:1.

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