Toner for electrostatic charge image development

Abstract

To provide toner for electrostatic charge image development which is excellent in both hot offset resistance and durability.SOLUTION: Toner for electrostatic charge image development contains a binder resin and a release agent, wherein the binder resin contains an amorphous polyester resin A which is a polycondensation product of an alcohol component that contains 50 mol% or more and 99 mol% or less of aliphatic diol and 1 mol% or more and 50 mol% or less of diol having a fluorene skeleton and has a content of diol having a bisphenol A skeleton of less than 10 mol%, and a carboxylic acid component.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a toner for developing electrostatic images used for developing latent images formed in, for example, electrophotography, electrostatic recording, electrostatic printing and the like. [Background technology]

[0002] As the alcohol component of polyester resins, alkylene oxide adducts of bisphenol A have conventionally been widely used, but in addition to this, examples have been reported in which bisphenol A having a fluorene skeleton is used (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-310257 A Summary of the Invention [Problem to be solved by the invention]

[0004] The toner binder resin and the release agent have high compatibility, and if the release agent is too dispersed, the release effect with the fixing roll is reduced and hot offset resistance is deteriorated. On the other hand, if the compatibility is low and the release agent dispersibility is low, durability during continuous printing is reduced.

[0005] The present invention relates to a toner for developing electrostatic images which is excellent in both hot offset resistance and durability. [Means for solving the problem]

[0006] The present invention relates to a toner for developing electrostatic images, which contains a binder resin and a release agent, and the binder resin contains 50 mol % or more and 99 mol % or less of an aliphatic diol and 1 mol % or more and 50 mol % or less of a diol having a fluorene skeleton, and contains an amorphous polyester resin A which is a polycondensate of an alcohol component having a bisphenol A skeleton of less than 10 mol % and a carboxylic acid component. Effect of the Invention

[0007] The toner for developing electrostatic images of the present invention exhibits excellent effects in terms of hot offset resistance and durability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The toner for developing electrostatic images of the present invention contains a binder resin and a release agent, and has a major feature in that the binder resin contains, as alcohol components, a predetermined amount of an aliphatic diol and a diol having a fluorene skeleton, and on the other hand, contains an amorphous polyester resin A in which the content of a diol having a bisphenol A skeleton is limited. Although the details of the reason why the effects of the present invention are achieved are not clear, it is presumed as follows.

[0009] The fluorene skeleton contained in the amorphous polyester resin A is highly hydrophobic, and therefore can improve the dispersibility of the hydrophobic release agent. In addition, the fluorene skeleton is more planar than the benzene ring, and therefore is more likely to stack, and can become a crystal nucleus through π-π interaction, thereby condensing the release agent around it and promoting crystallization. In order to achieve both hot offset resistance and durability of the toner, it is necessary to disperse the release agent appropriately. In the present invention, the fluorene skeleton has both the effect of dispersing the release agent in the binder resin and the effect of condensing it, so that the dispersion of the release agent can be kept optimal, and the hot offset resistance and durability of the toner can be achieved at the same time. However, when a hydrophobic monomer is used as the raw material monomer of the amorphous polyester resin, the hydrophobicity of the fluorene skeleton is hindered. In contrast, in the present invention, by using an aliphatic diol, which is a hydrophilic monomer, as the main component of the alcohol component of the amorphous polyester resin, the hydrophilicity and hydrophobicity of the fluorene skeleton part and other parts can be sharply balanced, and the effect of the present invention is significantly achieved, so that a higher level of hot offset resistance and durability can be achieved.

[0010] As described above, the amorphous polyester resin A contains a predetermined amount of an aliphatic diol and a diol having a fluorene skeleton, and is a polycondensation product of an alcohol component and a carboxylic acid component, in which the content of a diol having a bisphenol A skeleton is limited.

[0011] The crystallinity of a resin is represented by a crystallinity index defined as the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the value of [softening point / maximum endothermic peak temperature]. The crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. On the other hand, an amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index is greater than 1.4, preferably greater than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and the production conditions (e.g., reaction temperature, reaction time, cooling rate), etc. The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In the case of a crystalline resin, the maximum endothermic peak temperature is the melting point.

[0012] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, and neopentyl glycol.

[0013] The carbon number of the aliphatic diol is preferably 2 or more, more preferably 3 or more, from the viewpoint of durability, and is preferably 6 or less, more preferably 5 or less, from the viewpoint of hot offset resistance.

[0014] From the viewpoint of heat-resistant storage stability, the aliphatic diol is preferably an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom, such as 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, or 2,4-pentanediol, and more preferably 1,2-propanediol.

[0015] The content of the aliphatic diol in the alcohol component is 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and 99 mol% or less, preferably 90 mol% or less, more preferably 85 mol% or less.

[0016] In the diol having a fluorene skeleton, the fluorene skeleton is represented by the formula (I):

[0017] [ka]

[0018] (In the formula, R 1 and R 2 is a monovalent substituent, and m and n are 0 to 4. This refers to a structure represented by the formula:

[0019] In formula (I), R 1 and R 2 are each independently a monovalent substituent, and examples of the monovalent substituent include a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, an aryl group, an aralkyl group, and a -NO2 group. Among these, an alkyl group, an aryl group, or an aralkyl group is preferable, and an alkyl group is more preferable.

[0020] Examples of the alkyl group include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and t-butyl. The number of carbon atoms in the alkyl group is preferably 1 or more, and preferably 7 or less, more preferably 6 or less, and even more preferably 4 or less. The alkyl group is preferably an alkyl group having a carbon number of 1 to 4, and more preferably a methyl group.

[0021] Examples of the aryl group include aryl groups having 6 to 12 carbon atoms, such as a phenyl group and a naphthyl group.

[0022] Examples of the aralkyl group include a benzyl group, and an aralkyl group consisting of an aryl group having 6 to 12 carbon atoms and an alkyl group having 1 to 4 carbon atoms is preferred.

[0023] m R 1 and n R 2 can be selected independently. 1 and R 2 The substitution positions of are not particularly limited, but m and n are preferably 3 or less, more preferably 2 or less, and 0, i.e., R 1 and R 2 It is even more preferred that the polymer does not have

[0024] As the diol having a fluorene skeleton, from the viewpoint of reactivity with a carboxylic acid component, a compound having an alkylene oxide chain in addition to the fluorene skeleton is preferable, and for example, a compound represented by the formula (II):

[0025] [ka]

[0026] (In the formula, R 3 and R 4 is an alkylene group, R 5 ~R 8 is a hydrogen atom or a monovalent substituent, p and q each represent the average number of moles added and are positive numbers, the sum of p and q is 1 or more and 8 or less, R 1 , R 2 , m and n are the same as above) Preferred is a compound represented by the following formula:

[0027] In formula (II), R 3 and R 4 are each independently an alkylene group. The alkylene group is preferably a linear or branched alkylene group having 1 to 4 carbon atoms, more preferably a methylene group, an ethylene group, a propylene group, or a butylene group, still more preferably an ethylene group or a propylene group, and still more preferably an ethylene group.

[0028] p and q are each an alkylene oxide group (-OR 3 -), (-OR 4 -) represents the average number of moles added. The sum of p and q is 1 or more, preferably 1.5 or more, and 8 or less, preferably 4 or less. p and q are preferably 1 or more and 4 or less, more preferably 2 or less, and further preferably 1. In addition, p and q can be independently selected, but it is preferable that p and q are the same, and it is more preferable that p and q are 1. That is, it is preferable that the compound represented by formula (II) has two ethylene oxide chains.

[0029] -O-(R 3 O)pH, -O-(R 4 The substitution position of O)qH is not particularly limited, but it is preferable that it is substituted at the 4-position.

[0030] R 5 ~R8 are each independently a hydrogen atom or a monovalent substituent. Examples of the monovalent substituent include a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, an aryl group, an aralkyl group, and a -NO2 group, and these groups may further have a substituent such as an alkyl group, a cycloalkyl group, an aryl group, or a halogen atom. R 5 ~R 8 is preferably a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, more preferably a hydrogen atom or an alkyl group, and even more preferably a hydrogen atom. 1 and R 2 This is the same as that described for

[0031] R 5 ~R 8 The substitution positions are not particularly limited, but the 2-positions, 3-positions, 4-positions, 2-positions and 6-positions, and 3-positions and 5-positions are preferred.

[0032] Specific examples of the compound represented by formula (II) include 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-ethylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]fluorene, and 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]fluorene. 9,9-bis[4-(2-hydroxyethoxy)-3,5-dipropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diisopropylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-n-butylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-di-n-butylphenyl]fluorene fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-isobutylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diisobutylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-(1-methylpropyl)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-bis(1-methylpropyl)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diphenylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-benzylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dibenzylphenyl]fluorene, 9,9-bis[4-(3-hydroxypropoxy)phenyl]fluorene, 9,9-bis[4-(4-hydroxybutoxy)phenyl]fluorene, etc., which may be used alone or in combination of two or more. Among these, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (hereinafter also referred to as bisphenoxyethanolfluorene (BPEF)) is preferred.

[0033] 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene is obtained, for example, by adding ethylene oxide (hereinafter, abbreviated as EO) to 9,9-bis(4-hydroxyphenyl)fluorene. In this case, in addition to the 2EO adduct (9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene) in which one molecule of ethylene oxide is added to each of the hydroxyl groups of phenol, impurities such as 3EO adduct and 4EO adduct in which several molecules are added in excess may be contained. That is, the added ethylene oxide has a distribution, and the 2EO adduct may be one in which the maximum value of the distribution is the 2EO adduct. In order to improve the heat resistance of the polyester resin, the purity of the 2EO adduct is preferably 85% or more, more preferably 95% or more.

[0034] The content of the diol having a fluorene skeleton in the alcohol component is 1 mol % or more, preferably 5 mol % or more, more preferably 10 mol % or more, and 50 mol % or less, preferably 40 mol % or less, more preferably 30 mol % or less.

[0035] In the diol having a bisphenol A skeleton, the bisphenol A skeleton is represented by the formula (III):

[0036] [ka]

[0037] This refers to a structure represented by the formula:

[0038] As the diol having a bisphenol A skeleton, there is a diol having the formula (IV):

[0039] [ka]

[0040] (In the formula, OR 9 and R 10O is an oxyalkylene group, and R 9 and R 10 is an ethylene group or a propylene group, x and y are each a positive number representing the average number of moles of alkylene oxide added, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less. Examples of the bisphenol A include alkylene oxide adducts of bisphenol A, such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A, and bisphenol A, which are represented by the following formula:

[0041] The content of the diol having a bisphenol A skeleton in the alcohol component is less than 10 mol%, preferably 8 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, and even more preferably 0 mol%, i.e., the alcohol component does not contain a diol having a bisphenol A skeleton.

[0042] The diol having a fluorene skeleton does not have a bisphenol A skeleton, and the diol having a bisphenol A skeleton is a diol not having a fluorene skeleton.

[0043] From the viewpoint of heat resistance storage stability, the carboxylic acid component is preferably an aromatic dicarboxylic acid compound.

[0044] Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters having an alkyl group with a carbon number of 1 to 3. Among these, from the viewpoint of low-temperature fixability, terephthalic acid or isophthalic acid is preferred, and terephthalic acid is more preferred.

[0045] From the viewpoint of low-temperature fixing property, the content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 70 mol % or more, more preferably 80 mol % or more, even more preferably 90 mol % or more, even more preferably 95 mol % or more, and even more preferably 100 mol %.

[0046] Examples of other carboxylic acid components include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with a hydrocarbon group, aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid, trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0047] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monovalent carboxylic acid compound.

[0048] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and the carboxylic acid component.

[0049] From the viewpoint of adjusting the softening point of the polyester resin, the equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.3 or more, more preferably 0.4 or more, even more preferably 0.45 or more, and is preferably 0.9 or less, more preferably 0.7 or less, even more preferably 0.6 or less.

[0050] The amorphous polyester resin A can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and further, if necessary, in the presence of an esterification promoter, a polymerization inhibitor, etc., at a temperature of preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0051] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the esterification promoter include gallic acid. The amount of the esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0052] In the present invention, the polyester resin may be modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc., and among the modified polyester resins, urethane-modified polyester resins in which polyester resins are urethane-extended with a polyisocyanate compound are preferred.

[0053] The softening point of the amorphous polyester resin A is preferably 90° C. or higher, more preferably 100° C. or higher, from the viewpoint of heat-resistant storage stability, and is preferably 150° C. or lower, more preferably 140° C. or lower, from the viewpoint of low-temperature fixability.

[0054] The glass transition temperature of the amorphous polyester resin A is preferably 40° C. or higher, more preferably 50° C. or higher, and even more preferably 60° C. or higher, from the viewpoint of heat-resistant storage stability, and is preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 65° C. or lower, from the viewpoint of low-temperature fixability.

[0055] From the viewpoint of charging stability, the acid value of the amorphous polyester resin A is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, and preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less.

[0056] From the viewpoint of electrostatic stability, the hydroxyl value of the amorphous polyester resin A is preferably 100 mgKOH / g or more, more preferably 200 mgKOH / g or more, and is preferably 270 mgKOH / g or less, more preferably 230 mgKOH / g or less.

[0057] The weight average molecular weight of the amorphous polyester resin A is preferably 2,000 or more, more preferably 2,500 or more, and even more preferably 3,000 or more from the viewpoint of heat-resistant storage stability, and is preferably 7,000 or less, more preferably 4,000 or less, and even more preferably 3,300 or less from the viewpoint of low-temperature fixability.

[0058] The content of the amorphous polyester resin A in the binder resin is preferably 50% by mass or more, more preferably 60% by mass or more, and from the viewpoint of hot offset resistance, is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0059] It is preferable that the binder resin further contains an amorphous polyester resin B having a softening point higher than that of the amorphous polyester resin A.

[0060] The amorphous polyester resin B is preferably a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aromatic dicarboxylic acid compound.

[0061] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, and neopentyl glycol.

[0062] The carbon number of the aliphatic diol is preferably 2 or more from the viewpoint of durability, and is preferably 8 or less, more preferably 6 or less, from the viewpoint of hot offset resistance.

[0063] In the alcohol component of the amorphous polyester resin B, the content of the diol having a fluorene skeleton is less than 1 mol %, and preferably 0 mol %.

[0064] Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters having an alkyl group with a carbon number of 1 to 3. Among these, from the viewpoint of low-temperature fixability, terephthalic acid or isophthalic acid is preferred, and terephthalic acid is more preferred.

[0065] The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 50 mol % or more, more preferably 60 mol % or more, even more preferably 70 mol % or more, and is preferably 90 mol % or less, more preferably 85 mol % or less, even more preferably 80 mol % or less.

[0066] From the viewpoint of adjusting the softening point, the carboxylic acid component preferably further contains a trivalent or higher carboxylic acid compound.

[0067] Examples of the trivalent or higher carboxylic acid compound include trivalent or higher carboxylic acid compounds such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having an alkyl group with 1 to 3 carbon atoms.

[0068] The content of the trivalent or higher carboxylic acid compound in the carboxylic acid component is preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 15 mol % or more, and from the viewpoint of low-temperature fixability, it is preferably 50 mol % or less, more preferably 40 mol % or less, and even more preferably 30 mol % or less.

[0069] Examples of other carboxylic acid components include aliphatic dicarboxylic acids such as fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with a hydrocarbon group, glutaric acid, adipic acid, and sebacic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0070] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monovalent carboxylic acid compound.

[0071] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.75 or more, and is preferably 1.2 or less, more preferably 1.15 or less.

[0072] The polycondensation reaction conditions of the alcohol component and the carboxylic acid component are the same as those for the amorphous polyester resin A.

[0073] The softening point of the amorphous polyester resin B is preferably 120° C. or higher, more preferably 130° C. or higher, from the viewpoint of hot offset resistance, and is preferably 165° C. or lower, more preferably 150° C. or lower, from the viewpoint of low-temperature fixability.

[0074] The difference in softening point between amorphous polyester resin A and amorphous polyester resin B is preferably 15°C or more, more preferably 20°C or more, even more preferably 25°C or more, and is preferably 55°C or less, more preferably 45°C or less, even more preferably 35°C or less.

[0075] The glass transition temperature of the amorphous polyester resin B is preferably 40° C. or higher, more preferably 50° C. or higher, from the viewpoint of heat-resistant storage stability, and is preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 65° C. or lower, from the viewpoint of low-temperature fixability.

[0076] From the viewpoint of charging stability, the acid value of the amorphous polyester resin B is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 50 mgKOH / g or less, more preferably 45 mgKOH / g or less.

[0077] From the viewpoint of charging stability, the hydroxyl value of the amorphous polyester resin B is preferably 40 mgKOH / g or more, more preferably 50 mgKOH / g or more, and preferably 65 mgKOH / g or less, more preferably 60 mgKOH / g or less.

[0078] The weight average molecular weight of the amorphous polyester resin B is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 120,000 or more, from the viewpoint of hot offset resistance, and is preferably 200,000 or less, more preferably 175,000 or less, and even more preferably 160,000 or less, from the viewpoint of low-temperature fixability.

[0079] The content of the amorphous polyester resin B in the binder resin is preferably 10% by mass or more, more preferably 20% by mass or more, and from the viewpoint of low-temperature fixability, is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0080] The mass ratio of amorphous polyester resin A to amorphous polyester resin B (amorphous polyester resin A / amorphous polyester resin B) is preferably 50 / 50 or more, more preferably 60 / 40 or more, and even more preferably 65 / 35 or more, from the viewpoint of low-temperature fixability, and is preferably 90 / 10 or less, more preferably 80 / 20 or less, and even more preferably 75 / 25 or less, from the viewpoint of hot offset resistance.

[0081] The total content of amorphous polyester resin A and amorphous polyester resin B in the binder resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass.

[0082] Other binder resins include polyester resins other than amorphous polyester resin A and amorphous polyester resin B, such as crystalline polyester resins, vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins.

[0083] The content of the binder resin in the toner is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and is preferably 99% by mass or less, more preferably 98% by mass or less, even more preferably 95% by mass or less.

[0084] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts, and these can be used alone or in combination of two or more. In the present invention, the release agent preferably contains ester wax and / or paraffin wax from the viewpoint of durability.

[0085] The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, from the viewpoint of toner transferability, and is preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower, and even more preferably 110° C. or lower, from the viewpoint of low-temperature fixability.

[0086] The content of the release agent is, from the viewpoint of the low-temperature fixing property and offset resistance of the toner and the viewpoint of dispersibility in the binder resin, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 4 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 7 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0087] The toner for developing electrostatic images of the present invention may contain additives such as a colorant, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver, in addition to the binder resin and the release agent.

[0088] As the colorant, dyes, pigments, magnetic materials, etc. used as colorants for toners can be used. For example, carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. can be mentioned. In the present invention, the toner may be either a black toner or a color toner.

[0089] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0090] The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

[0091] Examples of the positively charged charge control agent include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", "Bontron N-07", "Bontron N-09", and "Bontron N-11" (all manufactured by Orient Chemical Industries Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX Examples of such resins include "VP435" (manufactured by Clariant), etc.; polyamine resins, such as "AFP-B" (manufactured by Orient Chemical Industry Co., Ltd.); imidazole derivatives, such as "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Kasei Corporation); and styrene-acrylic resins, such as "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.).

[0092] Examples of the negatively chargeable charge control agent include metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Aizenspiron Black TRH", and "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.); metal compounds of benzilic acid compounds such as "LR-147" and "LR-297" (all manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds such as "Bontron E-81", "Bontron E-84", "Bontron E-88", and "Bontron E-304" (all manufactured by Orient Chemical Industry Co., Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Industry Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts such as "COPY CHARGE NX VP434 (Clariant), nitroimidazole derivatives, and organometallic compounds.

[0093] From the viewpoint of the charging stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0094] The toner of the present invention may be a toner obtained by any of the conventionally known methods such as a melt-kneading method, an emulsion phase inversion method, a polymerization method, etc., but from the viewpoint of productivity and dispersibility of the colorant, a pulverized toner by a melt-kneading method is preferred. In the case of a pulverized toner by a melt-kneading method, for example, it is obtained by a method including a step of melt-kneading a mixture containing a binder resin and a release agent, and further, if necessary, additives such as a colorant and a charge control agent (melt-kneading step).

[0095] The mixture to be melt-kneaded may be kneaded all at once or in portions, but it is preferable to mix the mixture in advance in a mixer such as a Henschel mixer or a ball mill and then supply the mixture to the kneader.

[0096] The melt kneading can be carried out using a known kneading machine such as an internal kneader, a single-screw or twin-screw extruder, or an open roll type kneader.

[0097] The melt-kneading temperature is not particularly limited as long as the resin is melted and mixed at the temperature.

[0098] After the melt-kneading step, it is preferable to appropriately cool the kneaded mixture until it reaches a pulverizable hardness, and then, if necessary, perform a pulverizing step and a classification step to obtain toner particles. Here, cooling refers to cooling the kneaded mixture to 0°C or higher and 50°C or lower, or cooling to the glass transition temperature of the binder resin in the kneaded mixture or lower.

[0099] In the toner of the present invention, it is preferable to use an external additive in order to improve transferability.The external additive includes inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, zinc oxide, etc., and organic fine particles such as resin particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles, and two or more kinds may be used in combination.Among these, silica is preferable, and from the viewpoint of transferability of the toner, hydrophobic silica that has been hydrophobized is more preferable.

[0100] Examples of hydrophobic treatment agents for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0101] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle size of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0102] A mixer such as a Henschel mixer can be used to mix the toner particles and the external additives.

[0103] From the viewpoint of the electrostatic chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the toner particles before being treated with the external additive, and is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

[0104] The volume median particle size (D 50 ) is preferably 3 μm or more, more preferably 4 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less. 50) refers to the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle size. In addition, when the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is regarded as the volume median particle size of the toner.

[0105] The toner of the present invention can be used as it is as a toner for one-component development, or as a toner for two-component development mixed with a carrier, in an image forming apparatus of a one-component development system or a two-component development system, respectively. EXAMPLES

[0106] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Physical properties of resins and the like can be measured by the following methods.

[0107] [Softening point of resin] Using a flow tester "CFT-500D" (Shimadzu Corporation), 1g of sample is heated at a temperature increase rate of 6℃ / min while applying a load of 1.96MPa with the plunger, and extruding the sample from a nozzle with a diameter of 1mm and a length of 1mm. The amount of plunger descent of the flow tester is plotted against the temperature, and the temperature at which half of the sample has flowed out is taken as the softening point.

[0108] [Maximum endothermic peak temperature of resin] Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of sample into an aluminum pan, heat it to 200°C at a heating rate of 10°C / min, and then cool it to 0°C at a heating rate of 10°C / min. Next, heat the sample to 180°C at a heating rate of 10°C / min and measure it. The temperature of the endothermic peak with the largest peak area observed in the melting endothermic curve obtained is regarded as the maximum endothermic peak temperature.

[0109] [Glass transition temperature of resin] Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated from room temperature (20°C) to 200°C at a heating rate of 10°C / min, and cooled from that temperature to 0°C at a heating rate of 10°C / min. Next, the sample is heated to 180°C at a heating rate of 10°C / min, and the endothermic peak is measured. The temperature at the intersection of the extension of the baseline below the maximum endothermic peak temperature and the tangent showing the maximum slope from the rising part of the peak to the top of the peak is taken as the glass transition temperature.

[0110] [Acid value of resin] Measurements are performed based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and a mixture of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0111] [Hydroxyl value of resin] Measure based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070 to tetrahydrofuran.

[0112] [Weight average molecular weight of resin] The molecular weight distribution was measured by gel permeation chromatography (GPC) as follows, and the weight average molecular weight was determined. (1) Preparation of sample solution The sample was dissolved in tetrahydrofuran at 25° C. to a concentration of 0.5 g / 100 mL. Next, this solution was filtered using a fluororesin filter "DISMIC-25JP" (manufactured by ADVANTEC) with a pore size of 0.2 μm to remove insoluble matter, and a sample solution was obtained. (2) Molecular weight measurement The following measuring equipment and analytical column are used, tetrahydrofuran is used as the eluent at a flow rate of 1 mL per minute, and the column is stabilized in a thermostatic bath at 40°C. 100 μL of the sample solution is injected into the column for measurement. The molecular weight of the sample is calculated based on a calibration curve that has been prepared in advance. The calibration curve used here includes several types of monodisperse polystyrene "A-500" (5.0 x 10 2 ), "A-1000" (1.01 x 10 3 ), "A-2500" (2.63×10 3 ), "A-5000" (5.97 x 10 3 ), "F-1" (1.02 x 10 4 ), "F-2" (1.81 x 10 4 ), "F-4" (3.97 x 10 4 ), "F-10" (9.64×10 4 ), "F-20" (1.90×10 5 ), "F-40" (4.27×10 5 ), "F-80" (7.06×10 5 ), "F-128" (1.09×10 6 ) (all manufactured by Tosoh Corporation) were used as standard samples. The numbers in parentheses indicate the molecular weight. Measuring device: "HLC-8220CPC" (Tosoh Corporation) Analytical column: GMH XL " + "G3000H XL (Manufactured by Tosoh Corporation)

[0113] [Melting point of release agent] Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of sample into an aluminum pan, heat it to 200°C at a heating rate of 10°C / min, and then cool it to -10°C at a cooling rate of 5°C / min. Next, heat the sample to 180°C at a heating rate of 10°C / min and measure. The maximum endothermic peak temperature observed from the melting endothermic curve obtained is the melting point of the release agent.

[0114] [Average particle size of external additives] The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average of major and minor diameters) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these by number.

[0115] [Volume Median Particle Size of Toner] Measuring instrument: Coulter Multisizer III (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50μm Analysis software: Multisizer III version 3.51 (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Dispersion liquid: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) was dissolved in the electrolyte to adjust the concentration to 5% by mass. Dispersion conditions: 10 mg of the measurement sample is added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser (machine name: US-1, manufactured by SND Co., Ltd., output: 80 W). Then, 25 mL of electrolyte is added, and the mixture is further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured, and the volume median particle size (D 50 ) is required.

[0116] Resin manufacturing example 1 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the mixture was heated in a mantle heater in a nitrogen atmosphere at 180°C for 1 hour, and then heated from 180°C to 230°C at a rate of 10°C / h. After that, it was confirmed that the reaction rate reached 95% at 230°C, and the reaction was continued at 8 kPa until the desired softening point was reached, to obtain amorphous polyester resins (resins A1 to A4). In this specification, the reaction rate refers to the value of the amount of water produced by reaction (mol) / theoretical amount of water produced (mol)×100.

[0117] Resin manufacturing example 2 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C over 2 hours in a nitrogen atmosphere in a mantle heater. After that, it was confirmed that the reaction rate had reached 95% at 235°C, and the reaction was continued at 8 kPa until the desired softening point was reached, to obtain an amorphous polyester resin (resin A5).

[0118] Resin manufacturing example 3 The alcohol components shown in Table 1, carboxylic acid components other than trimellitic anhydride, and esterification catalyst were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the mixture was heated in a mantle heater in a nitrogen atmosphere at 180 ° C for 1 hour, and then heated from 180 ° C to 230 ° C at 10 ° C / h. After that, it was confirmed that the reaction rate reached 95% at 230 ° C, and the mixture was cooled to 180 ° C, and then trimellitic anhydride shown in Table 1 was added and heated to 220 ° C over 2 hours. After reacting at 220 ° C for 1 hour, the reaction was continued at 8 kPa until the desired softening point was reached, and an amorphous polyester resin (resin B1) was obtained.

[0119] [Table 1]

[0120] Examples 1 to 5 and Comparative Examples 1 and 2 100 parts by mass of the binder resin shown in Table 2, 1 part by mass of the negative charge control agent "Bontron E-81" (manufactured by Orient Chemical Industry Co., Ltd.), 5 parts by mass of the colorant "Pigment blue 15:3" (manufactured by Dainichiseika Color & Chemicals Co., Ltd., phthalocyanine blue), and 6 parts by mass of the release agent shown in Table 2 were thoroughly mixed in a Henschel mixer, and then melt-kneaded at a roll rotation speed of 200 r / min and a heating temperature of 100°C in the roll using a co-rotating twin-screw extruder with a total length of the kneading part of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The feed rate of the mixture was 20 kg / h, and the average residence time was about 18 seconds. The resulting melt-kneaded product was cooled and coarsely crushed, then crushed in a jet mill and classified to obtain a volume median particle size (D 50 ) yielded 8 μm toner particles.

[0121] To 100 parts by mass of the obtained toner particles, 1.0 part by mass of hydrophobic silica "AEROSIL NAX 50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: HMDS, average particle size: approximately 30 nm) was added as an external additive, and the mixture was mixed in a Henschel mixer to obtain a toner.

[0122] Test Example 1 [Hot offset resistance] The toner was mounted on a copy machine "AR-505" (manufactured by Sharp Corporation) whose fixing unit was modified to enable fixing outside the machine, and a printout was obtained in an unfixed state (print area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm 2 ). Then, using a fixing machine (fixing speed 300mm / sec) adjusted to a total fixing pressure of 40kgf, the temperature of the fixing roll was raised in increments of 5°C from 100°C to 200°C, and a fixing test was carried out on the unfixed printed matter at each temperature. The occurrence of hot offset was observed visually, and the temperature at which hot offset occurred was confirmed as hot offset resistance. The higher the temperature at which hot offset occurs, the better. The results are shown in Table 2. In the table, ">200" indicates that no hot offset occurred in the image fixed at 200°C.

[0123] Test Example 2 [Durability] The toner was loaded onto a printing machine "Page Presto N-4" (Casio Computer Co., Ltd., fixing: contact fixing method, development: non-magnetic one-component development method, development roll diameter: 2.3 cm) and a diagonal stripe pattern with a blackening rate of 5.5% was continuously printed in an environment of 32°C temperature and 85% humidity. During the printing, a solid black image was printed every 500 sheets and the presence or absence of streaks on the image was checked. Printing was stopped when streaks appeared on the image and continued up to a maximum of 9,000 sheets. The number of printed sheets until streaks were visually observed on the image was taken as the number of sheets on which streaks appeared due to toner fusing and adhering to the developing roll, and durability was evaluated. The higher the number of sheets without streaks, the better the durability of the toner. The results are shown in Table 2. In the table, ">9000" means that no streaks appeared even on the 9000th sheet printed.

[0124] [Table 2]

[0125] From the above results, it is apparent that Examples 1 to 5 are excellent in both hot offset resistance and durability. In contrast, a comparison between Comparative Examples 1 and 2 and Example 1 shows that by combining a diol having a fluorene skeleton with an aliphatic diol, rather than a diol having a bisphenol A skeleton, as the alcohol component of the amorphous polyester resin, durability is improved without impairing hot offset resistance. [Industrial Applicability]

[0126] The toner for developing electrostatic images of the present invention is suitably used for developing latent images formed in electrostatic image developing methods, electrostatic recording methods, electrostatic printing methods and the like.

Claims

1. A toner for developing electrostatic images containing a binder resin and a release agent, wherein the binder resin contains 50 mol % to 99 mol % of an aliphatic diol and 1 mol % to 50 mol % of a diol having a fluorene skeleton, and contains an amorphous polyester resin A which is a polycondensate of an alcohol component having a bisphenol A skeleton content of less than 10 mol % and a carboxylic acid component.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the weight average molecular weight of the amorphous polyester resin A is 7,000 or less.

3. 2. The toner for developing electrostatic images according to claim 1, wherein the content of the diol having a fluorene skeleton in the alcohol component is from 5 mol % to 40 mol %.

4. 2. The toner for developing electrostatic images according to claim 1, wherein the release agent contains an ester wax and / or a paraffin wax.