Wax composition for toner

Abstract

To provide a wax composition for toners that can contribute to improving the abrasion resistance and storage stability of printed materials. [Solution] A wax composition for toner containing a tetraester compound T having a specific structure and a ketone compound K having a specific structure, wherein the mass ratio of the tetraester compound T to the ketone compound K is 50:50 to 99:1, and the total content of the tetraester compound T and the ketone compound K in 100 parts by mass of the wax composition is 80 parts by mass or more.

Description

[Technical Field]

[0001] The present invention relates to a wax composition for toner that is suitably used for developing electrostatic images recorded by electrophotography, electrostatic recording, etc., in image forming apparatus such as photocopiers and laser printers. [Background technology]

[0002] Toner used in image forming devices such as photocopiers and printers contains a thermoplastic resin (hereinafter also simply referred to as "resin") which serves as a binder resin, along with a coloring agent (carbon black, magnetic powder, pigment, etc.), a charge control agent, and a wax, and optionally further contains a fluidity enhancer, a cleaning aid, a transfer aid, etc. Among these, the wax has the function of preventing toner from remaining on the fixing roll during fixing (filming) and promoting the softening of the resin to improve fixing performance.

[0003] In recent years, with the aim of improving productivity and saving energy, the development of printing presses capable of ultra-high-speed printing beyond conventional levels has progressed, and toners are required to meet these demands. In particular, when high-speed printing involving double-sided printing, peeling of text or images due to friction between sheets of paper is a problem, and there is a need for toners that can provide printed materials with excellent abrasion resistance. For example, Patent Document 1 states that by using a release agent (wax) containing a polyhydric alcohol ester and a partial ester of a polyhydric alcohol in a specific mass ratio, a toner can be obtained that has good low-temperature fixing performance and can form a highly robust image.

[0004] In addition, due to the increasing environmental awareness, there is a consideration to lower the set temperature of the image fixing unit of a printing machine for energy conservation. Therefore, while the development of toners with excellent low-temperature fixing properties, that is, those that soften at low temperatures, is in progress, when the printed materials obtained are stacked and stored over a long period of time, the phenomenon that the printed materials fuse together has become a problem, and there is a demand for a toner that can provide printed materials with excellent storage stability. However, in Patent Document 1, the storage stability of printed materials has not been examined.

[0005] On the other hand, Patent Document 2 describes that an electrostatic charge image developing toner containing a binder resin containing a specific amorphous composite resin and a crystalline polyester resin and a release agent (wax) can achieve both low-temperature fixing properties and the storage property of printed materials. However, in Patent Document 2, the abrasion resistance of printed materials has not been examined.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a wax composition for toner that can contribute to improving the abrasion resistance and storage stability of printed materials.

Means for Solving the Problems

[0008] The inventors of the present invention have found that a wax composition containing a specific tetraester compound T and a specific ketone compound K in a specific mass ratio improves the abrasion resistance and storage stability of printed materials, and have thus completed the present invention.

[0009] That is, the present invention is as follows. A toner wax composition containing a tetraester compound T represented by the following structural formula (I) and a ketone compound K represented by the following structural formula (II), where the mass ratio of the tetraester compound T to the ketone compound K (tetraester compound T: ketone compound K) is 50:50 to 99:1, and in 100 parts by mass of the wax composition, the total content of the tetraester compound T and the content of the ketone compound K is 80 parts by mass or more.

[0010]

Chemical formula

[0011]

Chemical formula

Advantages of the Invention

[0012] By incorporating the toner wax composition of the present invention into a toner, the rubbing resistance and storage stability of a printed matter obtained using the toner can be improved.

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the embodiments described in this specification and can be variously modified without departing from the gist of the present invention. Note that the "toner wax composition" of the present invention may sometimes be simply referred to as the "wax composition". In the present invention, a numerical range defined using the symbol "~" shall include the numerical values at both ends (upper limit and lower limit) of "~". For example, "2~10" represents a range from 2 or more to 10 or less. In the numerical range described in the present invention, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples or the value uniquely derived from the examples.

[0014] Since wax contained in the toner exists on the surface layer of the printed matter formed using the toner, the wax contained in the toner also affects the rubbing resistance and storage stability of the printed matter. The wax composition for toner of the present invention contains the tetraester compound T represented by the above structural formula (I) and the ketone compound K represented by the above structural formula (II), and the mass ratio of the tetraester compound T to the ketone compound K (tetraester compound T: ketone compound K) is 50:50 to 99:1, and in 100 parts by mass of the wax composition, the total content of the tetraester compound T and the content of the ketone compound K is 80 parts by mass or more. It is presumed that the wax composition for toner of the present invention improves the rubbing resistance and storage stability of the printed matter because when the tetraester compound T and the ketone compound K are mixed and used in the above specific mass ratio, these compounds take an appropriate eutectic state, and a highly crystalline mixture can be obtained without impairing the original characteristics of each compound.

[0015] 〔Tetraester compound T〕 The tetraester compound T contained in the wax composition for toner of the present invention is pentaerythritol tetraester represented by the following structural formula (I).

[0016]

Chemical formula

[0017] The wax composition of the present invention may contain only one compound as the tetraester compound T, or it may contain a combination of two or more compounds. In addition, in the present invention, R 1 CO, R 2 CO, R 3 CO and R 4 Without distinguishing between the CO groups, stereoisomers of the compound shown in structural formula (I) above are considered to be the same tetraester compound T. For example, R in structural formula (I) above 1 CO, R 2 CO, R 3 CO and R 4 When the number of carbon atoms in CO is denoted as C1, C2, C3, and C4, the tetraester compound T in Example (1) and the tetraester compound T in Example (2) are considered to be the same in this invention. Example (1): C1=18, C2=20, C3=22, C4=24 Example (2): C1=18, C2=22, C3=20, C4=24

[0018] Specific examples of the above-mentioned tetraester compound T include pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol tetrapalmitate, pentaerythritol tetraarachidate, pentaerythritol tetralignocellate, pentaerythritol monostearate tribehenate, pentaerythritol monoarachidate tribehenate, pentaerythritol monolignocellate tribehenate, pentaerythritol monopalmitate tristearate, pentaerythritol monostearate tripalmitate, and pentaerythritol monobehenate trilignocellate. In particular, from the standpoint of ease of manufacturing the wax composition and improving the abrasion resistance and storage stability of the printed material, at least one selected from the group consisting of pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol tetrapalmitate, pentaerythritol tetraarachidate, pentaerythritol tetralignocerate, and pentaerythritol monostearate tribehenate is preferably used, at least one selected from the group consisting of pentaerythritol tetrastearate, pentaerythritol tetrabehenate, and pentaerythritol monostearate tribehenate is more preferably used, and at least one selected from pentaerythritol tetrastearate and pentaerythritol tetrabehenate is particularly preferably used.

[0019] The above-mentioned tetraester compound T can be obtained, for example, by a dehydration condensation reaction between a straight-chain saturated fatty acid having 16 to 24 carbon atoms and pentaerythritol. Examples of linear saturated fatty acids having 16 to 24 carbon atoms include palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid. Among these, it is preferable to use linear saturated fatty acids having 18 to 22 carbon atoms, and it is particularly preferable to use at least one selected from the group consisting of stearic acid, arachidic acid, and behenic acid. By using such preferred linear saturated fatty acids, it is possible to obtain the wax composition of the present invention that exhibits a remarkable effect in improving the abrasion resistance and storage stability of printed materials.

[0020] [Ketone compound K] The ketone compound K contained in the toner wax composition of the present invention is an aliphatic ketone represented by the following structural formula (II).

[0021] [ka] [In structural formula (II), R 5 and R 6 Each of these independently represents a linear alkyl group with 15 to 23 carbon atoms.

[0022] The wax composition of the present invention may contain only one compound as the ketone compound K, or it may contain a combination of two or more compounds. Specific examples of the above ketone compound K include dipentadecylketone, dihexadecylketone, diheptadecylketone, dioctadecylketone, dinonanedecylketone, dieicosylketone, diheneicosylketone, didcosylketone, and ditricosylketone. Among these, at least one selected from the group consisting of dipentadecylketone, diheptadecylketone, dinonanedecylketone, diheneicosylketone, and ditricosylketone is preferably used from the viewpoint of ease of manufacturing the wax composition and improving the abrasion resistance and storage stability of printed materials, and at least one selected from the group consisting of dipentadecylketone, diheptadecylketone, dinonanedecylketone, and diheneicosylketone is particularly preferably used.

[0023] The above ketone compound K can be obtained, for example, by reacting a straight-chain saturated fatty acid having 16 to 24 carbon atoms with a metal oxide catalyst at a high temperature (preferably 300 to 350°C) and high pressure (preferably 0.1 to 5 MPa) to decarboxylate it. Examples of straight-chain saturated fatty acids having 16 to 24 carbon atoms include those similar to the straight-chain saturated fatty acids having 16 to 24 carbon atoms that can be used in the synthesis of the tetraester compound T mentioned above. Examples of metal oxide catalysts include magnesium oxide, calcium oxide, and zinc oxide. Alternatively, instead of using a straight-chain saturated fatty acid having 16 to 24 carbon atoms and a metal oxide catalyst, a metal salt of a straight-chain saturated fatty acid having 16 to 24 carbon atoms may be used. Examples of fatty acid metal salts include magnesium fatty acid salts, calcium fatty acid salts, and zinc fatty acid salts. Representative examples of fatty acid metal salts include magnesium stearate, calcium stearate, zinc stearate, magnesium behenate, calcium behenate, and zinc behenate.

[0024] [Wax composition for toner] The toner wax composition of the present invention contains the above-mentioned tetraester compound T and ketone compound K, and the mass ratio of tetraester compound T to ketone compound K (tetraester compound T:ketone compound K) is 50:50 to 99:1. From the viewpoint of improving the abrasion resistance and storage stability of printed materials, the above mass ratio is preferably 70:30 to 95:5. In the present invention, the mass of tetraester compound T may be represented as "(T)", the mass of ketone compound K may be represented as "(K)", and the mass ratio of tetraester compound T to ketone compound K may be represented as "(T):(K)".

[0025] Furthermore, the toner wax composition of the present invention has a total content of 80 parts by mass or more of the tetraester compound T and the ketone compound K in 100 parts by mass of the wax composition. From the viewpoint of improving the abrasion resistance and storage stability of printed materials, the total content of the tetraester compound T and the ketone compound K is preferably 85 parts by mass or more, more preferably 90 parts by mass or more, and even more preferably 95 parts by mass or more. The total content of the tetraester compound T and the ketone compound K may be 100 parts by mass, less than 100 parts by mass, 99.99 parts by mass or less, or 99.95 parts by mass or less.

[0026] The melting point of the toner wax composition of the present invention is preferably 65°C or higher, and more preferably 70°C or higher. The upper limit of the melting point of the toner wax composition of the present invention is not particularly limited, but from the viewpoint of usability as a toner wax, it is preferably 120°C or lower, and more preferably 100°C or lower. In this invention, the melting point refers to the temperature of the endothermic peak during melting, as measured by a differential scanning calorimeter (DSC).

[0027] The method for producing the wax composition for toner of the present invention is not particularly limited, as long as it is a method that yields the above-described wax composition for toner of the present invention. For example, the toner wax composition of the present invention may be produced by synthesizing tetraester compound T and ketone compound K separately and then mixing them. In this case, component X, which will be described later, may be further mixed. When mixing multiple types of compounds, it is preferable to heat each compound above its melting point, mix them uniformly, then cool them and perform a micronization process such as atomization. This can suppress variations in the quality of the resulting wax composition. Alternatively, the amount of raw materials may be adjusted so that the mass ratio (T):(K) of the tetraester compound T to the ketone compound K is within the above range, and the toner wax composition of the present invention may be produced by batch synthesis.

[0028] As an example of a method for producing the toner wax composition of the present invention, A step to prepare a tetraester wax containing the tetraester compound T shown in the above structural formula (I), A step of preparing a ketone wax containing the ketone compound K shown in the above structural formula (II), A manufacturing method can be given that includes the step of mixing the above-mentioned tetraester wax and the above-mentioned ketone wax. In the step of mixing the tetraester wax and the ketone wax described above, component X, described later, may be further mixed in.

[0029] The above-mentioned tetraester wax preferably contains one tetraester compound T as its main component, but may also contain two or more tetraester compounds T. In the present invention, the content of tetraester compound T contained in the tetraester wax may be referred to as "T purity". The T purity is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, as this makes it easier to obtain the wax composition of the present invention which has a high effect in improving the abrasion resistance and storage stability of printed materials.

[0030] The above-mentioned tetraester wax can be obtained, for example, by a method comprising the steps of: dehydrating and condensing a raw material fatty acid containing a straight-chain saturated fatty acid having 16 to 24 carbon atoms with pentaerythritol to obtain a crude product of the tetraester compound T represented by the above structural formula (I); and purifying the obtained crude product.

[0031] In the above dehydration condensation reaction, the molar ratio (COOH / OH) of the carboxyl groups of the fatty acid to the hydroxyl groups of pentaerythritol is preferably in the range of 1.10 to 1.01 from the viewpoint of the progress of the esterification reaction. The above dehydration condensation reaction may be carried out at high temperatures, such as 200°C or higher, or at low temperatures below 200°C using an acid catalyst such as p-toluenesulfonic acid. The crude product of the tetraester compound T obtained by the above dehydration condensation reaction may contain a partial ester of a linear saturated fatty acid having 16 to 24 carbon atoms and pentaerythritol, or unreacted raw materials, etc.

[0032] It is preferable to reduce the amount of unreacted raw material fatty acids contained in the tetraester wax by purifying the crude product of the tetraester compound T obtained by the above dehydration condensation reaction. This improves the purity of T in the resulting tetraester wax. Examples of purification treatments include distillation, recrystallization, and liquid-liquid treatment using a basic aqueous solution. It is particularly preferable to reduce the content of unreacted fatty acids by liquid-liquid treatment using a basic aqueous solution.

[0033] The acid value of the above tetraester wax is preferably 1 mg KOH / g or less, and more preferably 0.1 mg KOH / g or less, from the viewpoint of improving the abrasion resistance and storage stability of printed materials. Furthermore, the hydroxyl value of the tetraester wax is preferably 10 mg KOH / g or less, more preferably 5 mg KOH / g or less, from the viewpoint of improving the abrasion resistance and storage stability of printed materials. On the other hand, the hydroxyl value of the tetraester wax may be 1 mg KOH / g or more from the viewpoint of ease of manufacture.

[0034] The above ketone wax preferably contains one type of ketone compound K as its main component, but may also contain two or more types of ketone compounds K. In the present invention, the content of ketone compound K contained in the ketone wax may be referred to as "K purity". The K purity is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more, as this makes it easier to obtain the wax composition of the present invention that has a high effect in improving the abrasion resistance and storage stability of printed materials.

[0035] The above ketone wax can be obtained, for example, by a method that includes the steps of reacting a starting fatty acid containing a straight-chain saturated fatty acid having 16 to 24 carbon atoms in the presence of a metal oxide catalyst, and decarboxylating to obtain a crude product of ketone compound K represented by the above structural formula (II), and purifying the obtained crude product. The reaction temperature of the starting fatty acid to obtain ketone compound K may be, for example, 200 to 400°C. It is preferable to reduce the amount of metal oxide catalyst contained in the ketone wax by purifying the crude product of ketone compound K obtained by the above reaction.

[0036] The acid value of the above ketone wax is preferably 1 mg KOH / g or less, and more preferably 0.7 mg KOH / g or less, from the viewpoint of improving the abrasion resistance and storage stability of printed materials.

[0037] The raw material fatty acids used in the production of the above-mentioned tetraester wax and the raw material fatty acids used in the production of the above-mentioned ketone wax mainly consist of straight-chain saturated fatty acids having 16 to 24 carbon atoms, and their purity may be less than 100% by mass. The main component is preferably a straight-chain saturated fatty acid having 16 to 22 carbon atoms, and more preferably a straight-chain saturated fatty acid having 18 to 22 carbon atoms. In the present invention, the purity of the raw material fatty acids is the content of the fatty acid with the highest content when the total amount of raw material fatty acids is taken as 100% by mass. The raw material fatty acids may contain only one type of straight-chain saturated fatty acid having 16 to 24 carbon atoms, or may contain two or more types. In order to easily obtain the wax composition of the present invention which has a high effect in improving the abrasion resistance and storage stability of printed materials, the purity of the raw material fatty acids is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. Furthermore, in order to easily obtain the wax composition of the present invention, which has a high effect in improving the abrasion resistance and storage stability of printed materials, it is preferable that the fatty acids contained in the raw material fatty acids consist only of straight-chain saturated fatty acids having 14 to 24 carbon atoms, and more preferably that they consist only of straight-chain saturated fatty acids having 16 to 24 carbon atoms. In order to easily obtain the wax composition of the present invention, which has a high effect in improving the abrasion resistance and storage stability of printed materials, it is preferable that the content of linear saturated fatty acids having 16 to 24 carbon atoms is 95% by mass or more when the total amount of raw material fatty acids is 100% by mass, more preferably that the content of linear saturated fatty acids having 16 to 22 carbon atoms is 95% by mass or more, and even more preferably that the content of linear saturated fatty acids having 18 to 22 carbon atoms is 95% by mass or more.

[0038] The toner wax composition of the present invention may further enhance the effects of the present invention by containing a compound different from either the tetraester compound T or the ketone compound K (which may be referred to as "component X" in the present invention). The toner wax composition of the present invention may contain a β-ketocarboxylic acid compound C, described later, as component X, in order to further improve the abrasion resistance and storage stability of printed materials.

[0039] [β-ketocarboxylic acid compound C] In the present invention, β-ketocarboxylic acid compound C is a compound represented by the following structural formula (III).

[0040] [ka] [In structural formula (III), R 7 and R 8 Each of these independently represents a linear alkyl group having 14 to 22 carbon atoms.

[0041] When the toner wax composition of the present invention contains the above-mentioned β-ketocarboxylic acid compound C, the content of the β-ketocarboxylic acid compound C is preferably 0.01 to 0.1 parts by mass per 100 parts by mass of the wax composition. When the above-mentioned β-ketocarboxylic acid compound C is contained within this range, the toner wax composition of the present invention can further improve the abrasion resistance and storage stability of printed materials. This is presumed to be because a specific amount of the above-mentioned β-ketocarboxylic acid compound C moderately improves the crystallinity without affecting other properties of the wax composition.

[0042] The wax composition of the present invention may contain only one compound as the β-ketocarboxylic acid compound C, or it may contain a combination of two or more compounds. R in the above structural formula (III) 7 and R 8 Each of these is an independent linear alkyl group having 14 to 22 carbon atoms. From the standpoint of improving the scratch resistance and storage stability of printed materials, R 7 and R 8 The linear alkyl group represented by preferably includes at least a linear alkyl group having 14 to 20 carbon atoms, and preferably includes at least a linear alkyl group having 16 to 20 carbon atoms.

[0043] Furthermore, in order to improve the abrasion resistance and storage stability of printed materials, it is preferable that the content of linear alkyl groups having 14 to 20 carbon atoms is 95% by mass or more of the total mass of all linear alkyl groups in the β-ketocarboxylic acid compound C in the wax composition, and it is more preferable that the content of linear alkyl groups having 16 to 20 carbon atoms is 95% by mass or more.

[0044] The method for synthesizing the above-mentioned β-ketocarboxylic acid compound C is not particularly limited, and known methods or similar methods can be employed. For example, the above-mentioned β-ketocarboxylic acid compound C can be obtained by dimerizing a linear saturated fatty acid chloride having 16 to 24 carbon atoms in an organic base, and then hydrolyzing it. In this case, the organic base used for dimerization is not particularly limited, but in order to obtain the target product in good yield, it is preferable to use a tertiary amine compound due to its reactivity with the fatty acid chloride. Examples of tertiary amine compounds include triethylamine, triisopropylamine, and triphenylamine. Among these, triethylamine is preferred because it is easy to separate from the product. Furthermore, one type of fatty acid chloride can be used alone, or two or more types can be used in combination. It is preferable to use a basic aqueous solution for the above hydrolysis. From the viewpoint of suppressing the excessive formation of neutralization salts with the resulting β-ketocarboxylic acid compound, the amount of base used is preferably 1 mol% or less, and more preferably 0.5 mol% or less, based on 100 mol% of the theoretical amount of the β-ketocarboxylic acid compound to be produced. The type of base used is not particularly limited, and examples include potassium hydroxide, sodium hydroxide, potassium carbonate, potassium bicarbonate, sodium bicarbonate, etc., with potassium carbonate being preferred.

[0045] If the toner wax composition of the present invention contains the above component X, from the viewpoint of not impairing the effects of the present invention or improving the effects of the present invention, it is preferable that the total amount of the above β-ketocarboxylic acid compound C, the partial ester of pentaerythritol and a linear saturated fatty acid, and the linear saturated fatty acid be 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more, out of 100% by mass of the total amount of component X.

[0046] The content of each component constituting the wax composition can be calculated, for example, from the amount of raw materials added during manufacturing, or it can be measured by analyzing the wax composition using gas chromatography (GC). Furthermore, if the toner wax composition of the present invention contains two or more tetraester compounds T, the content of tetraester compounds T is the total content of multiple types of tetraester compounds T. If the toner wax composition of the present invention contains two or more ketone compounds K, the content of ketone compounds K is the total content of multiple types of ketone compounds K. If the toner wax composition of the present invention contains two or more β-ketocarboxylic acid compounds C, the content of β-ketocarboxylic acid compounds C is the total content of multiple types of β-ketocarboxylic acid compounds C.

[0047] The wax composition for toner of the present invention is contained in toner together with a binder resin, a colorant, a charge control agent, etc. Toner containing the wax composition for toner of the present invention is manufactured by a conventional method. The amount of the toner wax composition of the present invention contained in the toner is not particularly limited, but is usually 1 to 10 parts by mass per 100 parts by mass of binder resin. The wax composition for toner of the present invention is included in toner either alone or in combination of two or more types.

[0048] The binder resin is not particularly limited, and conventional binder resins used for toners, such as styrene resin, acrylic ester resin, styrene-acrylic ester copolymer resin, polyester resin, polyvinyl chloride resin, polyvinyl acetate resin, phenolic resin, epoxy resin, etc., can be used. The colorants are not particularly limited, and conventionally used toner colorants such as carbon black, magnetic powder, and various colored pigments can be used. [Examples]

[0049] The present invention will be further described below by illustrating examples of the production of the toner wax composition of the present invention and methods for evaluating it. However, the present invention is not limited to the following examples. Furthermore, parts and percentages are by mass unless otherwise specified.

[0050] [Synthesis of tetraester wax TW] Using the raw material fatty acids shown in Table 1 and pentaerythritol (Perstorp's "Penta mono", pentaerythritol purity 99%), tetraester waxes TW-1 to TW-8 shown in Table 2 were obtained by the method described in the synthesis example below.

[0051] <Synthesis Example 1: Synthesis of Tetraester Wax TW-1> In a 3 L four-necked flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and condenser, 200 g (1.47 mol) of pentaerythritol and 2062.1 g (6.05 mol) of fatty acid FA-1 were added and reacted at 240 °C under a nitrogen stream. The resulting crude ester product was 2232.3 g with an acid value of 8.7 mg KOH / g. To the crude ester product, 900 g of toluene and 500 g of 2-propanol were added, and a 10% by mass potassium hydroxide aqueous solution containing an amount of potassium hydroxide equivalent to 2.0 times the residual acid value of the crude ester product was added. The mixture was stirred at 70°C for 30 minutes. After standing for 30 minutes, 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 removed by distillation under reduced pressure of 1 kPa at 180°C, and the mixture was filtered to obtain 1800.7 g of tetraester wax TW-1.

[0052] <Synthesis Example 2: Synthesis of Tetraester Wax TW-2> Tetraester wax TW-2 was obtained in the same manner as in Synthesis Example 1, except that the raw material fatty acid was changed from FA-1 to FA-2.

[0053] <Synthesis Example 3: Synthesis of Tetraester Wax TW-3> In a 3 L four-necked flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and condenser, 200 g (1.47 mol) of pentaerythritol and 1918.1 g (5.71 mol) of fatty acid FA-2 were added and reacted at 240 °C under a nitrogen stream to obtain tetraester wax TW-3. The obtained tetraester wax TW-3 weighed 2010.2 g and had an acid value of 2.5 mg KOH / g.

[0054] <Synthesis Example 4: Synthesis of Tetraester Wax TW-4> Tetraester wax TW-4 was obtained in the same manner as in Synthesis Example 1, except that the raw material fatty acid was changed from FA-1 to FA-3.

[0055] <Synthesis Example 5: Synthesis of Tetraester Wax TW-5> Tetraester wax TW-5 was obtained in the same manner as in Synthesis Example 1, except that the raw material fatty acid was changed from FA-1 to FA-4.

[0056] <Synthesis Example 6: Synthesis of Tetraester Wax TW-6> Tetraester wax TW-6 was obtained in the same manner as in Synthesis Example 1, except that the raw material fatty acid was changed from FA-1 to FA-5.

[0057] <Synthesis Example 7: Synthesis of Tetraester Wax TW-7> Tetraester wax TW-1 (100 g) obtained in Synthesis Example 1 was dissolved in a mixture of toluene (900 g) and 2-propanol (100 g) at 80°C and recrystallized by slow cooling to room temperature. The obtained crystals were collected by filtration and the same procedure was repeated twice. Tetraester wax TW-7 was obtained by distilling off the solvent from the obtained crystals under reduced pressure conditions of 180°C and 1 kPa.

[0058] <Synthesis Example 8: Synthesis of Tetraester Wax TW-8> Tetraester wax TW-8 was obtained in the same manner as in Synthesis Example 1, except that the raw material fatty acid was changed from FA-1 to FA-6.

[0059] [Synthesis of ketone wax KW] Using the raw material fatty acids listed in Table 1, ketone waxes KW-1 to KW-5 shown in Table 3 were obtained by the method described in the synthesis example below.

[0060] <Synthesis Example 9: Synthesis of Ketone Wax KW-1> 588.9 g (2.0 mol) of fatty acid FA-4 and 40.3 g (1.0 mol) of magnesium oxide were weighed into a 1 L stainless steel pressure reactor, and the resulting mixture was heated to 250°C while blowing in nitrogen. At this time, the water in the mixture was distilled out of the system. Then, nitrogen was injected into the flask under pressure at 2 MPa, and the temperature of the mixture was raised to 340-350°C. The reaction was continued for 8 hours, and the reaction product was cooled to 100°C to obtain the crude ketone product. Under nitrogen injection at 100°C, the obtained crude ketone product was filtered using a 100-mesh metal strainer to remove the by-product magnesium oxide, yielding 503.5 g of ketone wax KW-1.

[0061] <Synthesis Example 10: Synthesis of Ketone Wax KW-2> Ketone wax KW-2 was obtained in the same manner as in Synthesis Example 9, except that the raw material fatty acid was changed from FA-4 to FA-1.

[0062] <Synthesis Example 11: Synthesis of Ketone Wax KW-3> Ketone wax KW-3 was obtained in the same manner as in Synthesis Example 9, except that the raw material fatty acid was changed from FA-4 to FA-5.

[0063] <Synthesis Example 12: Synthesis of Ketone Wax KW-4> Ketone wax KW-1 (100g) obtained in Synthesis Example 9 was dissolved in a mixture of toluene (900g) and 2-propanol (100g) at 80°C and recrystallized by slow cooling to room temperature. The obtained crystals were collected by filtration and the same procedure was repeated twice. Ketone wax KW-4 was obtained by distilling off the solvent from the obtained crystals under reduced pressure conditions of 180°C and 1kPa.

[0064] <Synthesis Example 13: Synthesis of Ketone Wax KW-5> Ketone wax KW-5 was obtained in the same manner as in Synthesis Example 9, except that the raw material fatty acid was changed from FA-4 to FA-6.

[0065] [Purity measurement] The content of tetraester compound T in tetraester wax TW (T purity) and the content of ketone compound K in ketone wax KW (K purity) were calculated by GC measurement. For the tetraester wax TW-8, the T purity was determined by calculating the content of tetraesters made from linear saturated fatty acids with 12-14 carbon atoms and pentaerythritol. For the ketone wax KW-5, the K purity was determined by calculating the content of linear saturated aliphatic ketones with 11-13 carbon atoms. GC measurements were performed using a gas chromatography system (Shimadzu Corporation, Nexus GC-2030). The column used was RESTEK MXT(registered trademark)-1HT SimDist. The column temperature was increased from a starting temperature of 100°C to 430°C at a rate of 10°C / min, and held at 430°C for 60 minutes. The injection temperature and detection temperature were both set at 430°C.

[0066] [Acid value and hydroxyl value] The acid value and hydroxyl value of tetraester wax TW and the acid value of ketone wax KW were measured. The acid value was measured according to JOCS (Japan Oil Chemists' Society) 2.3.1-1996, and the hydroxyl value was measured according to JOCS (Japan Oil Chemists' Society) 2.3.6.2-1996.

[0067] The raw material fatty acids FA-1 to FA-6 shown in Table 1 contained multiple types of straight-chain saturated fatty acids with different numbers of carbon atoms. In the raw material fatty acids shown in Table 1, C12, C14, C16, C18, C20, C22, and C24 represent the number of carbon atoms in the straight-chain saturated fatty acids, respectively. Table 1 also shows the mass percentage (mass%) of each straight-chain saturated fatty acid contained in each raw material fatty acid.

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] [Synthesis of β-ketocarboxylic acid compound C] β-ketocarboxylic acid compound C-1 was synthesized by the method shown in the synthesis example below.

[0072] <Synthesis Example 14: Synthesis of β-ketocarboxylic acid compound C-1> In a 500 mL four-necked flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and condenser, 300 mL of toluene and 50 g (0.17 mol) of stearate chloride (manufactured by Tokyo Chemical Industry Co., Ltd., purity 96% or higher) were added. While stirring the system, triethylamine (18.2 g (0.18 mol) was added dropwise. After the addition was complete, the reaction was allowed to continue for 2 hours, and then liquid-liquid separation with 50 g of water was performed 10 times. 1.2 g (0.01 mol) of potassium carbonate and 118.8 g of water were added to the resulting oil layer and reacted at 70°C for 15 minutes. After standing, the aqueous layer was removed. The remaining oil layer was left to stand at 50°C, and the resulting precipitate and potassium carbonate residue were removed by filtration. By distilling off toluene from the filtrate under reduced pressure, 10 g of β-ketocarboxylic acid compound C-1 was obtained. Furthermore, the obtained β-ketocarboxylic acid compound C-1 was analyzed using total internal reflection (TAF) with an IRTracer-100 (manufactured by Shimadzu Corporation). (1690~1740 cm) -1 and 1750~1800cm -1 By confirming the presence of a peak derived from the β-ketocarboxyl group, it was confirmed that the obtained β-ketocarboxylic acid compound C-1 is the compound shown in structural formula (III) above. Furthermore, GC measurement confirmed that of the total mass of all linear alkyl groups in β-ketocarboxylic acid compound C-1, 98% by mass were linear alkyl groups with 16 carbon atoms and 2% by mass were linear alkyl groups with 14 carbon atoms. Furthermore, when the acid value and melting point of the obtained β-ketocarboxylic acid compound C-1 were measured, the acid value was 97.5 mg KOH / g and the melting point was 56.5°C.

[0073] [Preparation of toner wax composition W] In a 0.3 L separable flask equipped with a stirring blade and a nitrogen inlet tube, the amounts of tetraester wax TW, ketone wax KW, β-ketocarboxylic acid compound C-1 (only for wax compositions W-5 to W-7), and behenic acid (only for wax composition W-16) shown in Table 4 were melted and mixed, and stirred at 150°C for 1 hour under a nitrogen stream. After cooling, solidification, and grinding, toner wax compositions W-1 to W-18 shown in Table 4 were obtained.

[0074] The amount of tetraester compound T represented by the above structural formula (I), the amount of ketone compound K represented by the above structural formula (II), the total content of these compounds, and the mass ratio (T):(K) of tetraester compound T to ketone compound K in 100 parts by mass of each toner wax composition were calculated from the T purity and amount added to tetraester wax TW, and the K purity and amount added to ketone wax KW. The calculation results are shown in Table 4. In Table 4, the content of tetraester compound T in wax composition W-17 refers to the content of tetraesters of linear saturated fatty acids with 12 to 14 carbon atoms and pentaerythritol. In addition, the content of ketone compound K in wax composition W-18 refers to the content of linear saturated aliphatic ketones with 11 to 13 carbon atoms. Each wax composition, except for wax composition W-13, contains a component X different from tetraester compound T or ketone compound K, and the total amount of the above-mentioned β-ketocarboxylic acid compound C, the partial ester of pentaerythritol and linear saturated fatty acid, and linear saturated fatty acid was 99% by mass or more of the total amount of component X.

[0075] The melting point of the wax composition was measured using a differential scanning calorimeter (DSC7000, Hitachi High-Tech Science Co., Ltd.) by the following procedure to determine the temperature of the endothermic peak during melting of the wax composition, which was then defined as the melting point of the wax composition. First, 10 mg of the measurement sample (wax composition) was weighed into an aluminum sample pan. The weighed measurement sample was heated to 200°C at a heating rate of 10°C per minute in a measurement folder into which nitrogen was blown at a flow rate of 60 ml per minute, and then cooled to 30°C at a cooling rate of 2°C per minute to ensure a uniform thermal history of the measurement sample. Subsequently, the measurement sample was heated from 30°C to 200°C at a heating rate of 10°C per minute to obtain a DSC curve during heating. An endothermic peak was observed during this heating. The temperature of this endothermic peak was defined as the melting point of the wax composition. If two or more endothermic peaks were observed, the temperature of the peak showing the largest endothermic amount was defined as the melting point of the wax composition.

[0076] [Table 4]

[0077] The wax compositions W-1 to W-13 of the present invention contained a tetraester compound T represented by the above structural formula (I) and a ketone compound K represented by the above structural formula (II), with (T):(K) being in the range of 50:50 to 99:1, and the total amount of tetraester compound T and ketone compound K in 100 parts by mass of the wax composition being 80 parts by mass or more. On the other hand, wax compositions W-14 to W-18 were not the wax compositions of the present invention in the following respects. Wax composition W-14 was a wax composition that did not contain the ketone compound K shown in the above structural formula (II). The wax composition W-15 had a (T):(K) ratio of 39:61, which was outside the range of 50:50 to 99:1. The wax composition W-16 contained less than 80 parts by mass of tetraester compound T and ketone compound K. Although wax composition W-17 contained a tetraester of a linear saturated fatty acid having 12 to 14 carbon atoms and pentaerythritol, it did not contain the tetraester compound T shown in the above structural formula (I). Although wax composition W-18 contained an aliphatic ketone having a linear alkyl group with 11 to 13 carbon atoms, it did not contain ketone compound K represented by the above structural formula (II).

[0078] [Creation of toner model samples] 95 parts by mass of polyester resin for toner (product name: Diacron ER-508, manufactured by Mitsubishi Rayon Co., Ltd.) and 5 parts by mass of the toner wax composition shown in Table 5 were mixed, and the mixture was melt-kneaded using a twin-screw compounder "Laboplastmill" (manufactured by Toyo Seiki Co., Ltd.) at 120°C and 80 rpm / min for approximately 10 minutes to obtain a resin mixture. The obtained resin mixture was pulverized and molded to a particle size of 100 μm or less, and then molded into cylindrical pellets with a diameter of 5 cm and a thickness of 5 mm using a tablet molding machine "Tabletop Hydraulic Molding Machine MP250" (manufactured by Maarsen Co., Ltd.) to produce toner model samples S-1 to S-18.

[0079] [Evaluation regarding improvement of scratch resistance of printed materials] A pellet-shaped toner model sample was heated on a hot plate heated to 160°C under a load of 500g for 1 second, and then cooled to room temperature. A friction test was performed on the heated surface using a Bowden tester under the following test conditions. Furthermore, in order to evaluate the improvement in abrasion resistance due to the wax composition, samples without the wax composition were prepared in the same manner as described above and evaluated as blank samples. (Test conditions) Steel ball: 3mm in diameter Load: 500g Speed: 10mm / s Measurement distance: 10mm Number of times: 1000

[0080] The wear depth of the sample surface after the friction test was measured using a contact-type film thickness gauge. Wear depth A of the toner model sample and wear depth A of the blank sample.B Therefore, according to the following formula (1), the wear reduction rate X due to containing the toner wax composition is calculated. A The wear reduction rate X was calculated. A Based on this, the effect of toner wax compositions on improving the abrasion resistance of printed materials was evaluated. The evaluation criteria were as follows. Note that the abrasion reduction rate X A The larger the value, the more the toner model sample can be evaluated as having improved abrasion resistance due to the inclusion of the wax composition. In other words, abrasion reduction rate X A The larger the value, the more effective the wax composition is in improving the abrasion resistance of toner-printed materials. X A =( A B -A) / A B Formula (1) (Evaluation Criteria) ◎(Shows excellent abrasion resistance improvement.) :X A ≥0.7 ○ (Sufficiently demonstrates improved abrasion resistance.) :0.7>X A ≥0.3 × (The effect of improving abrasion resistance is insufficient.) : 0.3 > X A

[0081] [Evaluation regarding improvements in the storage stability of printed materials] A pellet-shaped toner model sample was heated on a hot plate heated to 160°C under a load of 500g for 1 second, then cooled to room temperature. After that, it was left to stand for 24 hours in a high-temperature, high-humidity environment of 50°C and 50% relative humidity. The tack force of the toner model sample after standing was measured using a tacking tester (TAC-1000, manufactured by Resca) under the following test conditions. Specifically, the probe was pressed against the toner model sample with the following load, held for a predetermined time, and the force applied when peeling it off was defined as the tack force F. Furthermore, in order to evaluate the improvement in storage stability due to the wax composition, samples without the wax composition were prepared in the same manner as described above and evaluated as blank samples. (Test conditions) Probe: A metal probe with a Teflon® seal attached to the contact surface. Probe temperature: 50℃ Pressing time: 1 second Load: 900gf

[0082] Tack force F of toner model sample and tack force F of blank sample B Therefore, according to the following formula (2), the tack force reduction rate X due to containing the toner wax composition is calculated. F The following was calculated: Tack force reduction rate X F Based on this, the effect of toner wax compositions on improving the storage stability of printed materials was evaluated. The evaluation criteria were as follows. Note that the tack force reduction rate X F The larger the value of X, the more likely it is that the toner model samples have reduced tackiness due to the inclusion of the wax composition, thus suppressing fusion between the toner model samples. In other words, the tackiness reduction rate X F The larger the value, the more effective the wax composition is at suppressing the fusion of toner prints, that is, at improving the storage stability of toner prints. X F =(F B -F) / F B Formula (2) (Evaluation Criteria) ◎ (Shows excellent improvement in storage stability.) :X F ≥0.7 ○ (Sufficiently demonstrates improved storage stability.) :0.7>X F ≥0.3 × (The effect of improving storage stability is insufficient.) : 0.3 > X F

[0083] [Table 5]

[0084] The toner model samples S-1 to S-13 of Examples 1 to 13, which contained the toner wax compositions W-1 to W-13 of the present invention, showed improved abrasion resistance due to the inclusion of the toner wax compositions, thus demonstrating that the toner wax compositions W-1 to W-13 have the effect of improving the abrasion resistance of toner printed materials. Furthermore, the toner model samples S-1 to S-13 of Examples 1 to 13 showed reduced tack force due to the inclusion of the toner wax compositions, thus demonstrating that the toner wax compositions W-1 to W-13 have the effect of improving the storage stability of toner printed materials. In particular, toner wax compositions W-5 to W-7 containing β-ketocarboxylic acid compound C were excellent in both improving the abrasion resistance of toner prints and improving the storage stability of toner prints.

[0085] On the other hand, in the toner model samples S-14 to S-18 of Comparative Examples 1 to 5, which contained toner wax compositions W-14 to W-18, no improvement in abrasion resistance was obtained due to the inclusion of the toner wax compositions. Therefore, it was shown that toner wax compositions W-14 to W-18 do not have the effect of improving the abrasion resistance of toner printed materials. Furthermore, in the toner model samples S-15 to S-18 of Comparative Examples 2 to 5, which contained toner wax compositions W-15 to W-18, no reduction in tack force was obtained due to the inclusion of the toner wax compositions. Therefore, it was shown that toner wax compositions W-15 to W-18 do not have the effect of improving the storage stability of toner printed materials.

Claims

[Claim 1] This is a toner wax composition containing a tetraester compound T represented by the following structural formula (I) and a ketone compound K represented by the following structural formula (II). A wax composition for toner in which the mass ratio of the tetraester compound T to the ketone compound K (tetraester compound T:ketone compound K) is 50:50 to 99:1, and the total content of the tetraester compound T and the ketone compound K in 100 parts by mass of the wax composition is 80 parts by mass or more. 【Chemistry 1】 [In structural formula (I), R １ CO, R ２ CO, R ３ CO and R ４ Each of the COs independently represents a straight-chain saturated acyl group with 16 to 24 carbon atoms. 【Chemistry 2】 [In structural formula (II), R ５ and R ６ Each of these independently represents a linear alkyl group having 15 to 23 carbon atoms.

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