toner

Abstract

To provide a toner that contains a crystalline vinyl resin having good low temperature fixability and heat-resistant storage property, and can maintain its electrostatic propensity even in an environment where a large change in temperature and humidity occurs.SOLUTION: A toner contains a toner particle. The toner particle has a core containing a binder resin, and a shell covering the core. The binder resin contains a crystalline vinyl resin (A). The crystalline vinyl resin (A) contains a specific monomer unit (a) having at least two alkyl groups having 16-30 carbon atoms in an amount of 5.0 mass% or more with respect to the mass of the crystalline vinyl resin (A). The shell is an amorphous resin. The SP value of the amorphous resin and the SP value of the crystalline vinyl resin (A) satisfy a specific relationship.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a toner used in an electrophotographic method and an electrostatic recording method.

Background Art

[0002] Methods for visualizing image information using a toner such as the electrophotographic method are currently used in various fields, and improvements in performance such as higher image quality and energy savings are required. In the electrophotographic method, first, an electrostatic latent image is formed on an electrophotographic photoreceptor (image carrier) by a charging and exposure process. Next, the electrostatic latent image is developed with a developer containing toner, and a visualized image (fixed image) is obtained through a transfer process and a fixing process.

[0003] Among them, the fixing process is a process that requires relatively a lot of energy, and the development of a system and materials that achieve both energy savings and higher image quality has become an important technical issue. As an approach from the material aspect, a technique of using a crystalline resin for the binder resin of the toner has been studied. Since the molecular chains of the crystalline resin are regularly arranged, it hardly softens at temperatures lower than the melting point, so it has excellent heat-resistant storage properties. On the other hand, when the melting point is exceeded, the crystals rapidly melt, and a rapid decrease in viscosity occurs accordingly. Therefore, the crystalline resin is excellent in sharp meltability and has attracted attention as a material showing low-temperature fixability.

[0004] Known crystalline resins include main-chain crystalline resins in which the main chain crystallizes, typified by crystalline polyesters, and side-chain crystalline resins in which the side chain crystallizes, typified by long-chain alkyl acrylate polymers. Among them, side-chain crystalline resins are known to exhibit excellent low-temperature fixability because they are easy to increase the degree of crystallinity, and have been widely studied. Examples of the side-chain crystalline resin include crystalline vinyl resins. The crystalline vinyl resin has a long-chain alkyl group as a side chain, and shows crystallinity by the orientation of the long-chain alkyl groups in the side chain. Patent Document 1 discloses a toner using a crystalline vinyl resin, which is a toner using a crystalline vinyl resin obtained by copolymerizing a polymerizable monomer having a long-chain alkyl group and an amorphous polymerizable monomer having a different SP value. Although the crystalline vinyl resin exhibits excellent performance from the viewpoints of low-temperature fixability and heat-resistant storage stability, there are problems with chargeability due to its low charge retention. Patent Document 2 discloses a technique for solving the problem of chargeability by forming a shell with a uniform and high coverage rate using an amorphous resin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The technique of Patent Document 2 is an excellent technique for improving the chargeability, which is a problem of the crystalline vinyl resin. On the other hand, it has been found that when the product is transported by sea in a situation where temperature and humidity are not controlled, such as in a dry container of a cargo ship, excellent chargeability may not be exhibited after transportation. Cargo ships are exposed to an environment with a large day-night temperature and humidity difference depending on the region, weather, and loading position they pass through. For example, on a route passing directly under the equator, it is exposed to an environment where the cycle of rising from around 20°C at night to around 60°C during the day is repeated every day. With the recent global warming, the exposed environment is expected to become even more severe in the future.

[0007] As described above, although the chargeability has been improved by the conventional technology, it has been found that excellent chargeability may not be exhibited when transported by sea in a situation where temperature and humidity are not controlled. ​The present disclosure is directed to a toner containing a crystalline vinyl resin having excellent low-temperature fixability and heat-resistant storage stability, and which is less likely to exhibit a change in chargeability even in an environment where significant temperature and humidity changes occur.

Means for Solving the Problems

[0008] The present disclosure is a toner containing toner particles, wherein the toner particles have a core containing a binder resin and a shell covering the core, the binder resin contains a crystalline vinyl resin (A), the crystalline vinyl resin (A) contains 5.0% by mass or more of a monomer unit (a) represented by the following formula (1) based on the mass of the crystalline vinyl resin (A),

Chemical Formula

Advantages of the Invention

[0009] According to the present disclosure, there is provided a toner containing a crystalline vinyl resin having excellent low-temperature fixability and heat storage stability, which is less likely to cause a change in chargeability even in an environment where a significant temperature and humidity change occurs.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] In the present disclosure, the description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the lower limit and the upper limit which are the endpoints, unless otherwise specified. When the numerical ranges are described stepwise, the upper and lower limits of each numerical range can be arbitrarily combined. (Meth)acrylate means acrylate and / or methacrylate.

[0012] Also, in the present disclosure, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any one of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ. 。 "Monomer unit" refers to the reacted form of the monomer substance in the polymer. For example, in the main chain where vinyl monomers in the polymer are polymerized, one section of the carbon-carbon bond is taken as one unit. The vinyl monomer can be represented by the following formula (3).

Chemical formula

[0013] In formula (3), R A represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group), and RB represents an arbitrary substituent. In the present disclosure, the crystalline resin refers to a resin that exhibits a distinct endothermic peak in differential scanning calorimetry (DSC) measurement.

[0014] In order to solve the problem, the present inventors examined the mechanism by which the chargeability changes when temperature and humidity change. The binder resin of toner particles is hard below the melting point or the glass transition point, but it is not completely immobile at the molecular level, and molecular motion can occur. And this molecular motion becomes more active as the temperature is higher. Also, it is common that the resin expands when the temperature is high and contracts when it returns to normal temperature.

[0015] In situations where temperature control is not performed such as marine transportation, a large temperature change from around 20°C to around 60°C can occur repeatedly as described above. Therefore, the molecular motion, expansion, and contraction of the toner binder resin can occur repeatedly. And the present inventors recognized that when the affinity between the core of the toner particles and the shell covering the core is higher than a certain level, the chargeability is likely to change when repeatedly subjected to a large temperature change.

[0016] From these facts, the present inventors speculate on the mechanism by which the chargeability changes as follows. When the toner repeatedly undergoes a large temperature and humidity change, the molecular motion and the expansion and contraction of the resin in the toner particles occur. While this is repeated, when the core and the shell have an affinity of a certain level or more, a part of the resin molecules of the core and the shell are entangled. As a result, the phase separation between the shell provided for improving the chargeability and the core containing the crystalline vinyl resin having a problem in chargeability becomes unclear, and it is considered that the chargeability fluctuation has occurred.

[0017] In order to solve this problem, it is considered as one direction to reduce the affinity between the core and the shell. However, if the core and the shell do not have an affinity of a certain level or more, the core is likely to peel off from the shell. Therefore, it was difficult to solve the problem by lowering the affinity because it caused another problem.

[0018] In order to solve the above problems, the present inventors conducted further studies. As a second direction for preventing entanglement between the crystalline vinyl resin molecules of the core and the amorphous resin molecules of the shell, it is conceivable to restrict the movement of the resin molecules. However, generally, restricting the movement of the resin molecules also tends to increase the melting point and glass transition point, and a trade-off with low-temperature fixability is likely to occur. Therefore, it has been considered difficult to solve the problems by restricting the movement of the resin molecules.

[0019] Therefore, the present inventors further studied techniques for restricting the movement of resin molecules while minimizing the impact on low-temperature fixability. As a result, the present inventors found that by including a crystalline vinyl resin (A) in the binder resin contained in the core and containing the monomer unit (a) in an amount of 5.0% by mass or more based on the mass of the crystalline vinyl resin (A), the above problems can be solved. The present inventors speculate on this mechanism as follows.

[0020] The monomer unit (a) has a shorter distance between side chains compared to a crystalline vinyl resin containing an acrylate structure with a long-chain alkyl group in the side chain, which has been used in the prior art. When the distance between the long-chain alkyl groups in the side chains of a crystalline vinyl resin is short, the degree of freedom of the main chain and side chains is low, so the movement is relatively restricted. Therefore, by introducing the monomer unit (a) into the crystalline vinyl resin (A), it becomes possible to restrict the movement of the main chain and side chains, and it is considered that entanglement of the core and shell molecules can be suppressed even under significant temperature fluctuations. On the other hand, although the monomer unit (a) increases the crystal density, the crystallinity is not impaired, so it is considered that the impact on low-temperature fixability can be minimized.

[0021] Therefore, the present inventors have found that by the following technique, it is possible to provide a toner containing a crystalline vinyl resin having excellent low-temperature fixability and heat-resistant storage stability, and which is less likely to cause a change in chargeability even in an environment where significant temperature and humidity changes occur.

[0022] The present disclosure provides a toner comprising toner particles, The toner particles are A core containing a binder resin; a shell covering the core, The binder resin contains a crystalline vinyl resin (A), The crystalline vinyl resin (A) contains a monomer unit (a) represented by the following formula (1) in an amount of 5.0 mass% or more based on the mass of the crystalline vinyl resin (A): [ka] In the formula (1), R 1 ~R 4 At least two of the groups are independently -X-COOR 5 the rest are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, X is a single bond or an alkylene group having 1 or 2 carbon atoms, R 5 is an alkyl group having 16 to 30 carbon atoms, the shell is an amorphous resin, The SP value of the amorphous resin is S (J / cm 3 ) 0.5 The SP value of the crystalline vinyl resin (A) is A (J / cm 3 ) 0.5 When The SP S and SP A But, |SP S -SP A |≦5.0.

[0023] By including the crystalline vinyl resin (A) in the binder resin, the toner can exhibit good heat-resistant storage stability and good low-temperature fixing property. As mentioned above, the storage modulus of the crystalline vinyl resin is high up to the temperature required for heat-resistant storage stability, and the storage modulus drops sharply at higher temperatures, i.e., it exhibits sharp melting properties, which is believed to be the reason why such effects can be obtained.

[0024] The crystalline vinyl resin (A) contains 5.0% by mass or more of the monomer unit (a) represented by the formula (1) based on the mass of the crystalline vinyl resin (A). [Chemical formula] In the formula (1), among R 1 ~R 4 , at least two are each independently -X-COOR 5 , and the rest are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms. X represents a single bond or an alkylene group having 1 or 2 carbon atoms, and R 5 represents an alkyl group having 16 to 30 carbon atoms.

[0025] Since the crystalline vinyl resin (A) contains 5.0% by mass or more of the monomer unit (a), even when transported in an environment where significant temperature and humidity changes occur, it is less likely to cause a change in chargeability. The crystalline vinyl resin (A) preferably contains 30.0% by mass or more, more preferably 45.0% by mass or more of the monomer unit (a). The monomer unit (a) has a higher density of the side chain -X-COOR 5 that exhibits crystallinity compared to the acrylate structure of the prior art. Therefore, it is considered that the effect of suppressing the change in chargeability can be exerted.

[0026] The shell covering the core is an amorphous resin. By using an amorphous resin as the shell, it becomes possible to improve the problems of the crystalline vinyl resin having low charge retention. Also, in the toner, when the SP value of the amorphous resin of the shell is SP S (J / cm 3 ), and the SP value of the crystalline vinyl resin (A) is SP 0.5 (J / cm A ), when |SP 3 |≦5.0 is satisfied. The fact that the SP value is in the above range indicates that the affinity between the core and the shell is relatively high. |SP 0.5 and SP S and SP A satisfy |SP S -SP A |≦5.0. The fact that the SP value is in the above range indicates that the affinity between the core and the shell is relatively high. S-SP A | is preferably from 0.0 to 5.0, more preferably from 0.0 to 4.5, still more preferably from 0.0 to 4.0, and even more preferably from 2.0 to 4.0. Also, SP S ≧SP A is preferably the case. | SP S -SP A | can be controlled by the selection of the crystalline vinyl resin (A) and the monomers used for the amorphous resin.

[0027] From the viewpoints of uniform coating of the shell and adhesiveness, affinity is required between the core and the shell. | SP S -SP A | being within the above range enables the shell to be uniformly coated and results in good chargeability and heat-resistant storage stability. | SP S -SP A | exceeding 5.0 may lead to a decrease in heat-resistant storage stability. On the other hand, | SP S -SP A | being within the above range and having high affinity may cause problems in chargeability change in some cases. The mechanism is considered to be that because of the high affinity, the molecular chains of the core and the shell are likely to become entangled during repeated molecular motion as described above.

[0028] SP S (J / cm 3 ) 0.5 is preferably from 19.0 to 22.0, more preferably from 19.5 to 21.5. SP A (J / cm 3 ) 0.5 is preferably from 15.0 to 21.0, more preferably from 16.0 to 18.0.

[0029] Hereinafter, the toner will be described in detail. The toner contains toner particles. The toner particles may be used as the toner as they are, or may be used as the toner by mixing external additives or the like and attaching them to the surface of the toner particles if necessary. The toner particles have a core containing a binder resin and a shell covering the core. If necessary, a release agent, a colorant, a charge control agent, etc. may be contained.

[0030] <Binder resin> The binder resin contains a crystalline vinyl resin (A), and the crystalline vinyl resin (A) contains a monomer unit (a) represented by formula (1), and the content ratio thereof is 5.0% by mass or more based on the mass of the crystalline vinyl resin. By the content ratio (hereinafter also referred to as ratio J) of the monomer unit (a) represented by formula (1) being 5.0% by mass or more based on the mass of the crystalline vinyl resin (A), it is possible to obtain a toner that is less likely to cause a change in chargeability even when transported in an environment where significant temperature and humidity changes occur.

[0031] Ratio J is preferably 30.0% by mass or more, more preferably 45.0% by mass or more. For example, ratio J is preferably 5.0 to 90.0% by mass, more preferably 30.0 to 90.0% by mass, and even more preferably 45.0 to 85.0% by mass. Note that ratio J is preferably 0.7 mol% or more in terms of molar ratio. For example, ratio J is more preferably 4.0 to 40.0 mol% in terms of molar ratio, and even more preferably 20.0 to 35.0 mol% in terms of molar ratio. The method for introducing the monomer unit (a) into the crystalline vinyl resin will be described later. Also, ratio J can be controlled by the charged amount of raw materials when synthesizing the crystalline vinyl resin.

[0032] The crystalline vinyl resin (A) contains a monomer unit (a) represented by formula (1). In formula (1), R 1 ~R 4 Among them, at least two are each independently -X-COOR 5 (X is a single bond or an alkylene group having 1 or 2 carbon atoms, and R 5 is an alkyl group having 16 to 30 carbon atoms), and the rest are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0033] In the case of satisfying such a structure, in a toner containing a crystalline vinyl resin having excellent low-temperature fixability and heat-resistant storage stability, it is possible to provide a toner that is less likely to cause a change in chargeability even when transported in an environment where significant temperature and humidity changes occur. R1 ~R 4 Among them, when there is one part satisfying -X-COOR 5 and the rest are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, the density of the side chain is low, and thus the effect of suppressing the change in chargeability cannot be satisfied.

[0034] As the structure of the preferred substituent, R 1 ~R 4 Among them, two (more preferably one of R 1 and R 2 , and one of R 3 and R 4 , two) are each independently -X-COOR 5 (X is a single bond or an alkylene group having 1 or 2 carbon atoms, R 5 is an alkyl group having 16 to 30 carbon atoms), and the rest are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Further, among R 1 ~R 4 two (more preferably one of R 1 and R 2 , and one of R 3 and R 4 , two) are each independently -X-COOR 5 (X is a single bond or an alkylene group having 1 or 2 carbon atoms, R 5 is an alkyl group having 16 to 30 carbon atoms), and the rest are more preferably a hydrogen atom or a methyl group. Also, X is preferably a single bond.

[0035] R 5 is an alkyl group having 16 to 30 carbon atoms. When R 5 is an alkyl group having 16 to 30 carbon atoms, the crystalline vinyl resin is likely to exhibit crystallinity, and a toner excellent in low-temperature fixability can be obtained. Also, the heat-resistant storage stability is improved. When R 5 has less than 16 carbon atoms, the heat-resistant storage stability is likely to decrease, and when R 5 has more than 30 carbon atoms, the low-temperature fixability is likely to decrease. R 5is preferably an alkyl group having 18 to 28 carbon atoms, more preferably an alkyl group having 20 to 24 carbon atoms. R 5 The alkyl group is preferably linear.

[0036] The binder resin preferably contains 20.0% by mass or more of the crystalline vinyl resin (A) based on the mass of the binder resin (the content ratio of the crystalline vinyl resin (A) based on the mass of the binder resin is hereinafter also referred to as ratio I). When ratio I is 20.0% by mass or more, good low-temperature fixability can be obtained. Ratio I is more preferably 20.0 to 70.0% by mass, and even more preferably 40.0 to 60.0% by mass. Ratio I can be controlled by the charged amount of the crystalline vinyl resin (A) during toner particle production and the charged amounts of other materials.

[0037] In addition, in the viscoelasticity measurement of the toner, when the storage elastic modulus G' of the toner is 1.0×10 8 Pa, it is preferable that T1 (°C) satisfies 40.0 ≤ T1 ≤ 70.0. When T1 is in the above range, the problem of chargeability change is more likely to occur. That T1 is in the above range indicates that the decrease in the elasticity of the toner has started in the temperature range of 40.0 to 70.0 °C. Therefore, it is considered that the problem of chargeability change is more likely to occur in an environment where a large temperature and humidity change occurs. T1 (°C) is more preferably 50.0 to 65.0. T1 (°C) can be controlled by the molecular weight and crosslinking of the binder resin.

[0038] In addition, the crystalline vinyl resin (A) may or may not contain a monomer unit having an alkyl group with 16 to 30 carbon atoms different from the monomer unit (a) in addition to the monomer unit (a). In the crystalline vinyl resin (A), among the monomer units having an alkyl group with 16 to 30 carbon atoms including the monomer unit (a), the content ratio of the monomer unit (a) (hereinafter also referred to as ratio K) is preferably 50.0 to 100.0% by mass, more preferably 75.0 to 100.0% by mass, and even more preferably 90.0 to 100.0% by mass.

[0039] When the ratio K is within the above range, it is possible to further suppress the change in chargeability when transported in an environment where significant temperature and humidity changes occur. The fact that the ratio K is 50.0% by mass or more indicates that there are many sites with a high density of side chains. Therefore, it is considered that the movement of resin molecules is restricted and the change in chargeability can be further suppressed. The ratio K can be controlled by the charged amount of raw materials when synthesizing the crystalline resin (A).

[0040] In the crystalline vinyl resin (A), as a method for introducing the monomer unit (a) represented by the formula (1), there is a method of using a polymerizable ester, which is a condensate of a polyvalent carboxylic acid having 4 to 6 carbon atoms with a carbon-carbon double bond and a monoalcohol having an alkyl group with 16 to 30 carbon atoms, as a polymerizable monomer. The monomer unit (a) of the formula (1) may be used alone or in combination of two or more.

[0041] Examples of the polyvalent carboxylic acid having a carbon-carbon double bond and 4 to 6 carbon atoms include maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, glutaconic acid, trans-aconitic acid, cis-aconitic acid, and the like. Further, acid anhydrides or lower alkyl (1 to 4 carbon atoms) esters (for example, methyl ester, ethyl ester, isopropyl ester, etc.) of these polyvalent carboxylic acids may be used. The polyvalent carboxylic acid may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of maleic acid, fumaric acid, itaconic acid, and their acid anhydrides is preferable. More preferably, it is at least one selected from the group consisting of maleic acid, fumaric acid, and their acid anhydrides.

[0042] Examples of the monoalcohol having 16 to 30 carbon atoms and a chain hydrocarbon group include alcohols having a linear alkyl group (alkyl group having 16 to 30 carbon atoms) (cetyl alcohol, stearyl alcohol, 1-eicosanol, behenyl alcohol, 1-tetracosanol, 1-triacontanol, etc.) and alcohols having a branched alkyl group (alkyl group having 16 to 30 carbon atoms) (2-decyl-1-tetradecanol, etc.). Among these, from the viewpoint of crystallinity, an alcohol having a linear alkyl group (alkyl group having 16 to 30 carbon atoms) is preferable. More preferably, it is an alcohol having a linear alkyl group (alkyl group having 18 to 28 carbon atoms), and even more preferably, it is an alcohol having a linear alkyl group (alkyl group having 20 ~24) carbon atoms.

[0043] The method for producing the polymerizable ester is not particularly limited except for condensing a polyvalent carboxylic acid having a carbon-carbon double bond and 4 to 6 carbon atoms with a monoalcohol having 16 to 30 carbon atoms and a chain hydrocarbon group. In order to perform the condensation reaction reliably and prevent the reaction of the carbon-carbon double bond during the production of the polymerizable ester, it is preferable to use an esterification catalyst or a stabilizer (polymerization inhibitor).

[0044] The acid value of the crystalline vinyl resin (A) is preferably 3.0 mgKOH / g or less from the viewpoint of further improving the low-temperature fixability and further suppressing the change in chargeability when transported in an environment where a significant temperature and humidity change occurs. The acid value of the crystalline vinyl resin (A) is more preferably 0.0 to 1.0 mgKOH / g, and even more preferably 0.2 to 1.0 mgKOH / g. The fact that the acid value is 3.0 mgKOH / g or less indicates that there are few unreacted sites when synthesizing the crystalline vinyl resin (A). That is, since there are few sites without a monoalcohol attached, it is considered that the crystal density is high. In order to control the acid value within the above range, it can be controlled by the ratio of carboxylic acid to alcohol when synthesizing the crystalline resin, etc.

[0045] In addition to the monomer unit (a) represented by the formula (1), the crystalline vinyl resin (A) may contain other monomer units. The crystalline vinyl resin (A) may have a plurality of other monomer units. As a method for introducing other monomer units, there is a method of polymerizing the above polymerizable ester and other vinyl monomers. The crystalline vinyl resin (A) is preferably a polymer of the above polymerizable ester and other vinyl monomers.

[0046] Examples of other vinyl monomers include the following. Styrene, α-methylstyrene, (meth)acrylic acid methyl esters such as (meth)acrylic acid methyl, (meth)acrylic acid ethyl, (meth)acrylic acid -n-butyl, (meth)acrylic acid -t-butyl, (meth)acrylic acid -2-ethylhexyl. Monomers having a urea group: For example, amines having 3 to 22 carbon atoms [primary amines (normal butylamine, t-butylamine, propylamine, isopropylamine, etc.), secondary amines (di-normal ethylamine, di-normal propylamine, di-normal butylamine, etc.), aniline, cyclohexylamine, etc.] and ethylenically unsaturated isocyanates having 2 to 30 carbon atoms reacted by a known method, etc. Monomers having a carboxy group; for example, methacrylic acid, acrylic acid, (meth)acrylic acid -2-carboxyethyl. Monomers having a hydroxy group; for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc. Monomers having an amide group; for example, acrylamide, monomers obtained by reacting an amine having 1 to 30 carbon atoms with a carboxylic acid having 2 to 30 carbon atoms having an ethylenically unsaturated bond (such as acrylic acid and methacrylic acid) by a known method. Monomers having a lactam structure; for example, N-vinyl-2-pyrrolidone.

[0047] Among them, it is preferable that the crystalline vinyl resin (A) contains, in addition to the monomer unit (a), a monomer unit (b) different from the monomer unit (a). And when the SP value of the monomer unit (a) is SPa (J / cm 3 ) 0.5 , and the SP value of the monomer unit (b) is SPb (J / cm 3 ) 0.5 , it is preferable to satisfy the following formula (2). However, when there are two or more other monomer units used in addition to the monomer unit (a) represented by formula (1), among these, the one having the largest difference from the SP value of the monomer unit (a) is taken as the monomer unit (b). 3.0 ≦ |SPb - SPa| ≦ 21.0 ···(2)

[0048] Since the relationship between the SP value SPa of the monomer unit (a) and the SP value SPb of the monomer unit (b) is within the above range, even when transported in an environment where significant temperature and humidity changes occur, changes in chargeability can be further suppressed. When the above |SPb - SPa| is satisfied, the crystalline part and the amorphous part in the crystalline vinyl resin (A) are likely to form a clear phase separation state, so the density of the crystalline part increases further and molecular motion can be more suppressed. It is considered that the relationship between SPa and SPb more preferably satisfies formula (4). 7.0 ≦ |SPb - SPa| ≦ 12.0 ···(4)

[0049] The crystalline vinyl resin (A) preferably contains a monomer unit corresponding to methacrylonitrile. The crystalline vinyl resin (A) preferably contains 1.0 to 25.0% by mass of the monomer unit corresponding to methacrylonitrile, more preferably 10.0 to 20.0% by mass. Also, the crystalline vinyl resin (A) preferably contains a monomer unit corresponding to styrene. The crystalline vinyl resin (A) preferably contains 1.0 to 60.0% by mass of the monomer unit corresponding to styrene, more preferably 4.0 to 10.0% by mass.

[0050] The crystalline vinyl resin (A) may be produced by any known method within the scope of the present configuration, but it is preferably produced by polymerizing a composition of polymerizable monomers containing the above polymerizable ester with an initiator or the like.

[0051] As the polymerization initiator, a known polymerization initiator can be used. For example, azo-based or diazo-based polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; peroxide-based polymerization initiators such as benzoyl peroxide, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxyisobutyrate, t-butyl peroxyneodecanoate, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide. Also, known chain transfer agents and polymerization inhibitors may be used.

[0052] In addition to the crystalline vinyl resin (A), the binder resin may further contain an amorphous vinyl resin (B). Examples of the polymerizable monomer used for the amorphous vinyl resin (B) include styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, and p-phenylstyrene. (Meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate (n-butyl (meth)acrylate, t-butyl (meth)acrylate, etc.), and 2-ethylhexyl (meth)acrylate. Examples thereof include acrylonitrile, methacrylonitrile, and (meth)acrylic acid.

[0053] The amorphous vinyl resin (B) is preferably a polymer of a monomer mixture containing styrene and butyl (meth)acrylate. The content ratio of the amorphous vinyl resin (B) based on the mass of the binder resin is preferably 30.0 to 80.0% by mass, more preferably 40.0 to 60.0% by mass.

[0054] <Release agent> The toner particles may contain a release agent. The release agent is preferably at least one selected from the group consisting of hydrocarbon waxes and ester waxes. By using hydrocarbon waxes and / or ester waxes, it becomes easier to ensure effective releasability. The release agent more preferably contains ester wax.

[0055] The hydrocarbon wax is not particularly limited, and examples thereof include the following. Aliphatic hydrocarbon waxes: low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight olefin copolymers, Fischer-Tropsch waxes, or waxes obtained by oxidizing or adding acid to these.

[0056] The ester wax only needs to have at least one ester bond in one molecule, and either natural ester wax or synthetic ester wax may be used. The ester wax is not particularly limited, and examples thereof include the following. Esters of monohydric alcohols and monocarboxylic acids such as behenyl behenate, stearyl stearate, and palmityl palmitate; Esters of dihydric carboxylic acids and monoalcohols such as dibehenyl sebacate; Esters of dihydric alcohols and monocarboxylic acids such as ethylene glycol distearate and hexanediol dibehenate; Esters of trihydric alcohols and monocarboxylic acids such as glycerin tribehenate; Esters of tetrahydric alcohols and monocarboxylic acids such as pentaerythritol tetrastearate and pentaerythritol tetrapalmitate; Esters of hexahydric alcohols and monocarboxylic acids such as dipentaerythritol hexastearate, dipentaerythritol hexapalmitate, and dipentaerythritol hexabehenate; Esters of polyfunctional alcohols and monocarboxylic acids such as polyglycerin behenate; natural ester waxes such as carnauba wax and rice wax;

[0057] Among them, esters of hexahydric alcohols and monocarboxylic acids such as dipentaerythritol hexastearate, dipentaerythritol hexapalmitate, and dipentaerythritol hexabehenate, and esters of octahydric alcohols and monocarboxylic acids such as tripentaerythritol octastearate, tripentaerythritol octapalmitate, and tripentaerythritol octabehenate are preferred.

[0058] In the toner, the content of the release agent in the toner particles is preferably 1.0% by mass or more and 30.0% by mass or less, more preferably 2.0% by mass or more and 25.0% by mass or less. When the content of the release agent in the toner particles is within the above range, the releasability during fixing is easily ensured. The melting point of the release agent is preferably 60°C or higher and 120°C or lower. When the melting point of the release agent is within the above range, it melts during fixing and easily penetrates the surface of the toner particles, and the releasability is easily exhibited. More preferably, it is 70°C or higher and 100°C or lower.

[0059] <Colorant> The toner particles may contain a colorant. Examples of the colorant include known organic pigments, organic dyes, inorganic pigments, carbon black as a black colorant, magnetic particles, and the like. In addition, colorants conventionally used in toners may also be used. Examples of the colorant for yellow include the following. Condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds. Specifically, C.I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155 , 168, 180 are preferably used.

[0060] Examples of the colorant for magenta include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds. Specifically, C.I. Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254 are preferably used. Examples of the colorant for cyan include the following. Copper phthalocyanine compounds and their derivatives, anthraquinone compounds, basic dye lake compounds. Specifically, C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66 are preferably used.

[0061] The colorant is selected from viewpoints such as hue angle, chroma, lightness, lightfastness, coloring power, and the like. The content of the colorant is preferably 1.0 to 20.0 parts by mass with respect to 100.0 parts by mass of the binder resin. When magnetic particles are used as the colorant, the content is preferably 40.0 to 150.0 parts by mass with respect to 100.0 parts by mass of the binder resin.

[0062] <Charge control agent> The toner particles may contain a charge control agent as needed. Also, the charge control agent may be externally added to the toner particles. By blending the charge control agent, the charge characteristics can be stabilized and the optimum charge amount can be controlled according to the development system. As the charge control agent, known ones can be used, and in particular, a charge control agent with a fast charging speed and capable of stably maintaining a certain charge amount is preferable.

[0063] Examples of the charge control agent for controlling the toner to be negatively chargeable include the following. Organometallic compounds and chelate compounds are effective, and examples include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Examples of the charge control agent for controlling the toner to be positively chargeable include the following. Examples include nigrosine, quaternary ammonium salts, metal salts of higher fatty acids, diorganotin borates, guanidine compounds, and imidazole compounds. The content of the charge control agent is preferably 0.01 to 20.0 parts by mass, more preferably 0.5 to 10.0 parts by mass with respect to 100.0 parts by mass of the toner particles.

[0064] <Shell> The toner particles include a shell that coats the core. The shell is an amorphous resin. By the shell being an amorphous resin, the charge retention property, which is a problem of crystalline resins, can be improved. The amorphous resin used for the shell layer is |SP S -SP AAs long as it satisfies ≦5.0, there is no particular limitation, and known amorphous resins can be used. Specifically, examples include polyester resins, polyurethane resins, polyamide resins, vinyl resins, and the like. Among them, from the viewpoint of charge retention, it is preferable that the shell contains at least one selected from the group consisting of amorphous polyester resins and amorphous vinyl resins. More preferably, the shell contains an amorphous polyester resin.

[0065] The polyester resin can be obtained by the reaction of a polyvalent carboxylic acid having a valence of 2 or more and a polyhydric alcohol. It can be done. Examples of the polyvalent carboxylic acid include the following compounds. Dibasic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, malonic acid, dodecenyl succinic acid, and anhydrides or lower alkyl esters thereof, and aliphatic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid. 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and anhydrides or lower alkyl esters thereof. These may be used alone or in combination of two or more.

[0066] Examples of the polyhydric alcohol include the following compounds. Alkylene glycols (ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol); alkylene ether glycols (polyethylene glycol and polypropylene glycol); alicyclic diols (1,4-cyclohexanedimethanol); bisphenols (bisphenol A); alkylene oxide (ethylene oxide and propylene oxide) adducts of alicyclic diols or bisphenols.

[0067] The alkyl moieties of alkylene glycols and alkylene ether glycols may be linear or branched. Furthermore, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc. These may be used alone or in combination of two or more. For the purpose of adjusting the acid value and hydroxyl value, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can also be used as necessary.

[0068] The method for producing the polyester resin is not particularly limited. For example, the transesterification method or the direct polycondensation method can be used alone or in combination. The production of the polyester resin is preferably carried out at a polymerization temperature between 180 °C and 230 °C. If necessary, the inside of the reaction system is depressurized, and the reaction is preferably carried out while removing water and alcohol generated during condensation. When the monomer is not soluble or compatible at the reaction temperature, it is advisable to add a high-boiling solvent as a dissolution aid to dissolve it. In the polycondensation reaction, it is carried out while distilling off the dissolution aid solvent. When a monomer with low compatibility exists in the copolymerization reaction, it is preferable to condense the monomer with low compatibility in advance with the acid or alcohol planned for polycondensation and then carry out polycondensation together with the main component.

[0069] Examples of catalysts that can be used in the production of polyester include the following. Titanium catalysts such as titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, and titanium tetrabutoxide. Tin catalysts such as dibutyltin dichloride, dibutyltin oxide, and diphenyltin oxide.

[0070] The amorphous vinyl resin is preferably a synthetic resin whose main chain is bonded by vinyl polymerization, such as polystyrene. Examples of the polymerizable monomer used in the amorphous vinyl resin include styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, and p-phenylstyrene. (Meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples include acrylonitrile, methacrylonitrile, and (meth)acrylic acid.

[0071] Also, the amorphous vinyl resin preferably does not contain the monomer unit (a) represented by the formula (1). Note that two or more kinds of amorphous resins may be contained as the shell. In that case, SP S is the SP value of the amorphous resin with the highest content.

[0072] The content of the amorphous resin in the shell is preferably 0.1 part by mass or more and 40.0 parts by mass or less, more preferably 0.2 part by mass or more and 30.0 parts by mass or less, still more preferably 0.4 part by mass or more and 25.0 parts by mass or less, even more preferably 3.8 parts by mass or more and 10.0 parts by mass or less, and particularly preferably 5.5 parts by mass or more and 8.0 parts by mass or less, based on 100 parts by mass of the binder resin.

[0073] In an image obtained by observing the cross-section of the toner with a transmission electron microscope (TEM), it is preferable that the shell is observed over 70.0% or more of the outer circumference length of the core (the ratio of the length of the outer circumference of the core where the shell is observed is hereinafter also referred to as the coverage rate). The coverage rate is more preferably 90.0% or more. The coverage rate is preferably, for example, 70.0 to 100.0%, and more preferably 90.0 to 99.0%. When the coverage rate is within the above range, the effect of improving the chargeability is particularly good. This is presumably because the periphery of the core containing a crystalline resin that easily leaks charges can be sufficiently covered with an amorphous resin that hardly leaks charges. The coverage rate of the shell can be controlled by the addition amount and addition method of the material forming the shell.

[0074] Further, in an image obtained by observing the cross-section of the toner with a transmission electron microscope (TEM), it is preferable that the toner particles further have a second shell that covers the shell of the amorphous resin and is different from the shell of the amorphous resin. The presence of the second shell makes it less likely for the chargeability to change even during further long-term transportation. It is more preferable that the second shell contains an organosilicon polymer or a melamine resin. It is even more preferable that the second shell is an organosilicon polymer. The organosilicon polymer is heat-resistant and is particularly unlikely to cause a change in chargeability even during further long-term transportation. For the same reason, melamine resin is also preferable as the second shell. As the melamine resin, for example, polymers of methylol melamine such as hexamethylol melamine can be used.

[0075] The method for forming the shell of the organosilicon polymer is not particularly limited, and known methods can be used. For example, the sol-gel method can be mentioned. The sol-gel method is a method in which a liquid raw material is used as a starting material, hydrolyzed and subjected to condensation polymerization, and gelled through a sol state, and is used in methods for synthesizing glass, ceramics, organic-inorganic hybrids, and nanocomposites. By using this production method, functional materials of various shapes such as surface layers, fibers, bulk bodies, and fine particles can be produced from the liquid phase at low temperature. The shell of the organosilicon polymer is preferably produced by hydrolysis and condensation polymerization of a silicon compound typified by alkoxysilane.

[0076] The organosilicon polymer is preferably a polycondensate of an organosilicon compound having a structure represented by the following formula (Y).

Chemical formula

[0077] In formula (Y), Ra represents a hydrocarbon group having 1 to 6 carbon atoms (preferably an alkyl group having 1 to 6 carbon atoms), and Rb, Rc, and Rd each independently represent a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group. Ra is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and more preferably a methyl group.

[0078] Rb, Rc, and Rd each independently represent a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group (hereinafter also referred to as a reactive group). These reactive groups undergo hydrolysis, addition polymerization, and polycondensation to form a crosslinked structure. From the viewpoint of mild hydrolyzability at room temperature and precipitation property on the surface of toner particles, it is preferably an alkoxy group having 1 to 3 carbon atoms, and more preferably a methoxy group or an ethoxy group.

[0079] In addition, the hydrolysis, addition polymerization, and condensation polymerization of Rb, Rc, and Rd can be controlled by the reaction temperature, reaction time, reaction solvent, and pH. To obtain an organosilicon polymer, one or more organosilicon compounds having three reactive groups (Rb, Rc, and Rd) in one molecule excluding Ra shown in the above formula (Y) (hereinafter also referred to as trifunctional silane) may be used in combination.

[0080] Examples of the compound represented by the above formula (Y) include the following. Trifunctional methylsilanes such as methyltrimethoxysilane, methyltriethoxysilane, methyldiethoxymethoxysilane, methylethoxydimethoxysilane, methyltrichlorosilane, methylmethoxydichlorosilane, methylethoxydichlorosilane, methyldimethoxychlorosilane, methylmethoxyethoxychlorosilane, methyldiethoxychlorosilane, methyltriacetoxysilane, methyldiacetoxymethoxysilane, methyldiacetoxyethoxysilane, methylacetoxydimethoxysilane, methylacetoxymethoxyethoxysilane, methylacetoxydiethoxysilane, methyltrihydroxysilane, methylmethoxydihydroxysilane, methylethoxydihydroxysilane, methyldimethoxyhydroxysilane, methylethoxymethoxyhydroxysilane, methyldiethoxyhydroxysilane.

[0081] Among them, the compound represented by the formula (Y) is preferably methyltrimethoxysilane and methyltriethoxysilane, and more preferably methyltriethoxysilane. The content of the second shell is preferably 1.0 part by mass or more and 10.0 parts by mass or less, more preferably 2.0 parts by mass or more and 8.0 parts by mass or less, and still more preferably 3.0 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0082] <Method for Producing Toner Particles> The method for producing toner particles is not particularly limited. Any known method such as suspension polymerization method, emulsion aggregation method, dissolution suspension method, and pulverization method may be adopted, but the toner particles are preferably produced by the suspension polymerization method. The toner particles are preferably suspension polymerization toner particles. The suspension polymerization method will be described in detail.

[0083] For example, a previously synthesized crystalline vinyl resin (A) is added to a mixture of polymerizable monomers for producing an amorphous vinyl resin (B), for example. If necessary, other materials such as a colorant, a release agent, and a charge control agent are added and uniformly dissolved or dispersed to prepare a polymerizable monomer composition. Thereafter, the polymerizable monomer composition is dispersed in an aqueous medium using a stirrer or the like to prepare suspended particles of the polymerizable monomer composition. Thereafter, the toner particles are obtained by polymerizing the polymerizable monomer contained in the particles with an initiator or the like.

[0084] As an example for forming a shell on the toner particles by the suspension polymerization method, by adding a highly hydrophilic amorphous resin to the raw materials, the amorphous resin migrates to the surface layer of the toner particles when polymerizing in water, and a shell can be formed.

[0085] Further, when forming the second shell, it is preferable to form the second shell after forming the shell of the amorphous resin. For example, a method of adding a hydrolysis solution of a silicon compound to an aqueous medium containing toner particles having a shell of an amorphous resin and carrying out polycondensation of the silicon compound to form the second shell can be mentioned. Also, for example, a method of adding a raw material of a melamine resin to an aqueous medium containing toner particles having a shell of an amorphous resin and generating a melamine resin to form the second shell can be mentioned. The toner particles may be filtered, washed, and dried by a known method. Further, an external additive may be added as necessary to obtain a toner.

[0086] The aqueous medium may contain an inorganic or organic dispersion stabilizer. As the dispersion stabilizer, a known dispersion stabilizer can be used. Examples of the inorganic dispersion stabilizer include phosphates such as hydroxyapatite, tricalcium phosphate, dicalcium phosphate, magnesium phosphate, aluminum phosphate, and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; sulfates such as calcium sulfate and barium sulfate; calcium metasilicate; bentonite; silica; and alumina.

[0087] On the one hand, examples of organic dispersion stabilizers include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salts, and starch.

[0088] When using an inorganic compound as the dispersion stabilizer, commercially available products may be used as they are, or in order to obtain finer particles, the inorganic compound may be generated in an aqueous medium and then used. For example, in the case of calcium phosphate such as hydroxyapatite or tricalcium phosphate, it is advisable to mix an aqueous phosphate solution and an aqueous calcium salt solution under high stirring.

[0089] The aqueous medium may contain a surfactant. As the surfactant, known surfactants can be used. Examples include anionic surfactants such as sodium dodecylbenzenesulfate and sodium oleate; cationic surfactants; amphoteric surfactants; nonionic surfactants, etc.

[0090] <External additive> The toner particles may be used as the toner as they are, or, if necessary, an external additive or the like may be mixed and adhered to the surface of the toner particles to be used as the toner. Examples of the external additive include inorganic fine particles selected from the group consisting of silica fine particles, alumina fine particles, and titania fine particles, or their composite oxides. Examples of the composite oxides include silica-aluminum fine particles and strontium titanate fine particles. The content of the external additive is preferably 0.01 parts by mass or more and 8.0 parts by mass or less, and more preferably 0.1 parts by mass or more and 4.0 parts by mass or less, based on 100 parts by mass of the toner particles.

[0091] The calculation methods and measurement methods for various physical properties of the toner and toner materials are described below. <Method for separating toner particles from toner> When analyzing toner particles, if the surface of the toner particles is treated with an external additive or the like, the external additive is separated by the following method to obtain toner particles. Add 160 g of sucrose (manufactured by Kinoshita Chemical Co., Ltd.) to 100 mL of ion-exchanged water and dissolve it while stirring with a hot water bath to prepare a thick sucrose solution. Put 31 g of the above thick sucrose solution and 6 mL of Contaminon N (a 10% by mass aqueous solution of a neutral detergent for precision measuring instruments with a pH of 7 composed of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) into a centrifuge tube to prepare a dispersion. Add 1.0 g of toner to this dispersion and loosen the toner lumps with a spatula or the like. Shake the centrifuge tube with a shaker (sold by AS ONE Corporation) at 350 spm (strokes per min) for 20 min. After shaking, transfer the solution to a glass tube (50 mL) for a swing rotor and centrifuge it (H-9R Manufactured by Kokusan Co., Ltd.) at 3500 rpm for 30 min. By this operation, the toner particles and the detached external additive are separated. Visually confirm that the toner particles and the aqueous solution are sufficiently separated, and collect the separated toner particles in the uppermost layer with a spatula or the like. After filtering the collected toner with a vacuum filter, dry it with a dryer for 1 hour or more to obtain toner particles. Repeat this operation multiple times to ensure the required amount.

[0092] <Method for Separating Tetrahydrofuran (THF) Insoluble Matter> When separating the THF insoluble matter from the toner particles, the separation is performed according to the following procedure. Weigh accurately 1.5 g of toner particles from which the THF insoluble matter is to be separated (0.7 g when measuring the THF insoluble matter of the resin alone, W[g]), put it into a pre-weighed cylindrical filter paper (product name: No. 86R, size 28×100 mm, manufactured by Advantec Toyo Co., Ltd.), and set it in a Soxhlet extractor. Extract with 200 mL of tetrahydrofuran (THF) as a solvent for 18 hours, and perform the extraction at a reflux rate such that the extraction cycle of the solvent is once every 5 minutes. After the extraction is completed, the cylindrical filter paper is taken out, air-dried, and then vacuum-dried at 40°C for 8 hours. The mass of the cylindrical filter paper containing the extraction residue is weighed, and the mass of the extraction residue (W2 [g]) is calculated by subtracting the mass of the cylindrical filter paper. On the other hand, the mass of the soluble component (W1 [g]) is calculated by sufficiently distilling off THF from the soluble component in THF using an evaporator.

[0093] <Method for Separating Crystalline Vinyl Resin (A) and Amorphous Resin from Toner Particles> The separation of the crystalline vinyl resin (A) and the amorphous resin from the toner particles can be carried out by a known method, and an example is shown below. As a method for separating the resin component from the toner particles, gradient LC is used. In this analysis, regardless of the molecular weight, separation can be carried out according to the polarity of the resin in the binder resin. First, the toner particles are dissolved in chloroform. The sample was adjusted to a sample concentration of 0.1% by mass with chloroform, and the solution filtered through a 0.45 μm PTFE filter was used for measurement. The gradient polymer LC measurement conditions are shown below. Apparatus: UlTIMATE3000 (manufactured by Thermo Fisher Scientific) Mobile phase: A Chloroform (HPLC), B Acetonitrile (HPLC) Gradient: 2 min (A / B = 0 / 100) → 25 min (A / B = 100 / 0) (Note that the gradient of the change in the mobile phase was made linear.) Flow rate: 1.0 mL / min Injection: 0.1% by mass × 20 μL Column: Tosoh TSKgel ODS (4.6 mm φ x 150 mm x 5 μm) Column temperature: 40°C Detector: Corona charged particle detector (Corona-CAD) (Therm o Fisher Scientific) Regarding the time-intensity graph obtained by measurement, the resin components can be separated into two peaks according to polarity. Then, perform the above measurement again, and by fractionating at the time corresponding to the trough of each peak, it is possible to separate into two types of resins. Perform DSC measurement on the separated resins, and define the resin with a melting point peak as crystalline vinyl resin (A) (mass W11 [g]), and the resin without a melting point peak as amorphous resin (mass W12 [g]).

[0094] In addition, when the toner particles contain a release agent, it is necessary to separate the release agent from the toner particles in advance. The separation of the release agent is carried out by recycling HPLC to separate components with a molecular weight of 3000 or less as the release agent. Note that the molecular weight at the time of separation can be changed according to the molecular weight of the release agent. The measurement method is shown below. First, prepare a chloroform solution of the toner by the method described above. Then, filter the obtained solution through a solvent-resistant membrane filter "Micron Disc" (manufactured by Tosoh Corporation) with a pore diameter of 0.2 μm to obtain a sample solution. Note that the sample solution is adjusted so that the concentration of the components soluble in chloroform is 1.0% by mass. Using this sample solution, perform measurements under the following conditions. · Apparatus: LC-Sakura NEXT (manufactured by Japan Analytical Industry Co., Ltd.) · Column: JAIGEL2H, 4H (manufactured by Japan Analytical Industry Co., Ltd.) · Eluent: Chloroform · Flow rate: 10.0 ml / min · Oven temperature: 40.0 °C · Sample injection volume: 1.0 ml When calculating the molecular weight of the sample, use the molecular weight calibration curve prepared using a standard polystyrene resin (for example, trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation). From the molecular weight curve thus obtained, repeatedly fractionate the components with a molecular weight of 3000 or less to remove the release agent (mass W3 [g]) from the toner particles.

[0095] <Measurement Method of Differential Scanning Calorimetry (DSC)> The presence or absence of crystalline resin and the endothermic peak temperature of the melting point are measured in accordance with ASTM D3418-82 using a differential scanning calorimeter "Q2000" (manufactured by TA Instruments). For temperature correction of the apparatus detection part, the melting points of indium and zinc are used, and for heat quantity correction, the heat of fusion of indium is used. For the measurement of toner, first, 10 mg of toner is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference. In the first heating process, the measurement sample is heated from 20 °C to 180 °C at a rate of 10 °C / min while measuring to obtain a differential scanning calorimetry curve A. Then, after holding at 180 °C for 10 minutes, a cooling process is performed while cooling from 180 °C to 10 °C at a rate of 10 °C / min to obtain a differential scanning calorimetry curve B. Further, after holding at 10 °C for 10 minutes, in the second heating process, measurement is performed while heating from 10 °C to 180 °C at a rate of 10 °C / min again to obtain a differential scanning calorimetry curve C. The temperature of the peak top of the peak appearing in the obtained differential scanning calorimetry curve C is determined and taken as the endothermic peak temperature of the melting point.

[0096] <Measurement of Content Ratio of Each Component in Toner Particles> From each mass described in the above-mentioned <Separation Method of Tetrahydrofuran (THF) Insoluble Matter> and <Separation Method of Crystalline Vinyl Resin and Amorphous Vinyl Resin from Toner Particles>, the content ratio of each component in toner particles is calculated as follows. [Mass Ratio of Crystalline Vinyl Resin Based on the Mass of Binder Resin: Ratio I (Unit: Mass %)] I = (W11 / (W11 + W12)) × 100

[0097] <Measurement Method of Content Ratio of Various Monomer Units such as Monomer Unit (a) in Resin and Carbon Number of Alkyl Group> The measurement of the content ratio of various monomer units such as monomer unit (a) in resin and the carbon number of the alkyl group is 1 performed by 1H-NMR under the following conditions. As the measurement sample, the crystalline vinyl resin separated by the above method can be used. Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measuring frequency: 400 MHz Pulse condition: 5.0 μs Frequency range: 10500 Hz Number of integrations: 64 times Measuring temperature: 30 °C Sample: 50 mg of the sample to be measured is placed in a sample tube with an inner diameter of 5 mm, and deuterated chloroform (CDCl3) is added as a solvent, and this is dissolved in a thermostat at 40 °C for preparation. The obtained 1 1H-NMR chart is analyzed to identify the structure of each monomer unit. Here, as an example, the measurement of the content ratio of the monomer unit (a) in the crystalline vinyl resin and the number of carbon atoms of the alkyl group will be described. The obtained 1 In the 1H-NMR chart, from the peaks attributed to the components of the monomer unit (a), a peak independent of the peaks attributed to the components of other monomer units is selected, and the integral value S1 of this peak is calculated. For the other monomer units contained in the crystalline vinyl resin, the integral values are calculated in the same way.

[0098] For example, when the monomer units constituting the crystalline vinyl resin are the monomer unit (a) and one other monomer unit, the content ratio of the monomer unit (a) is obtained as follows using the above integral value S1 and the integral value S2 of the peak of the other monomer unit. Note that n1 and n2 are the numbers of hydrogens in the components to which the peaks focused on each site are attributed. Content ratio of monomer unit (a) (mol%) = {(S1 / n1) / ((S1 / n1)+(S2 / n2))}×100 Even when there are two or more other monomer units, the content ratio of the monomer unit (a) can be calculated in the same way (using S3···Sx, n3···nx). Also, the number of carbon atoms of the alkyl group can be 1 calculated from the integration ratio of the proton peaks in the 1H-NMR chart.

[0099] When a polymerizable monomer that does not contain a hydrogen atom in components other than the vinyl group is used, 13 using C-NMR, the measured nucleus is 13 C, and measurement is performed in single pulse mode, 1 and it is calculated in the same manner by H-NMR.

[0100] Multiply the ratio (mol%) of each monomer unit calculated by the above method by the molecular weight of each monomer unit to convert the content ratio of each monomer unit to mass%. Thereby, based on the mass of the crystalline vinyl resin, the mass ratio J of the monomer unit (a) represented by the formula (1) is calculated. [Content ratio of monomer unit (a) based on the mass of crystalline vinyl resin (A): ratio J (unit: mass%)] J = { (S1 / n1) × M1 / ((S1 / n1) × M1 + (S2 / n2) × M2)} × 100

[0101] Also, when a monomer unit having an alkyl group with 16 to 30 carbon atoms exists in addition to the monomer unit (a) represented by the formula (1), the content ratio (ratio K) of the monomer unit (a) in the monomer unit having an alkyl group with 16 to 30 carbon atoms is calculated as follows. For example, when the unit having an alkyl group with 16 to 30 carbon atoms is a monomer unit (a) and one other monomer unit, it is calculated by the following formula using the above integral value S1 and the integral value S3 of the peak of the other monomer unit. [Mass ratio of monomer unit (a) in monomer unit having an alkyl group with 16 to 30 carbon atoms: ratio K (unit: mass%)] Ratio K = { (S1 / n1) × M1 / ((S1 / n1) × M1 + (S3 / n3) × M3)} × 100 However, M1 and M3 are the molecular weights of each monomer unit. The same method is used for measurement in the amorphous vinyl resin.

[0102] [Calculation method of solubility parameter (SP value)] The SP value was determined as follows according to the calculation method proposed by Fedors. First, the SP value of the monomer unit constituting the resin is determined as follows. Here, the monomer unit constituting the resin means the molecular structure in which the double bond of the monomer used when obtaining the resin by polymerization is cleaved by polymerization. For example, when calculating the SP value (σm) (J / cm 3 ) 0.5 of the monomer unit, the evaporation energy (Δei) (J / mol) and the molar volume (Δvi) (cm 3 / mol) are obtained from the table described in "Polym. Eng. Sci., 14(2), 147 - 154(1974)" for the atoms or atomic groups in the molecular structure of the monomer unit, and calculated from the following formula. σm=(ΣΔei / ΣΔvi) 0.5

[0103] The SP value of the resin is obtained by determining the evaporation energy (Δei) and the molar volume (Δvi) of the monomer units constituting the resin for each monomer unit. Then, the product with the molar ratio (j) of each monomer unit in the resin is calculated respectively, and the sum of the evaporation energies of each monomer unit is divided by the sum of the molar volumes, and calculated from the following formula. σp={(Σj×ΣΔei) / (Σj×ΣΔvi)} 0.5 For example, assuming that the resin is composed of two types of monomer units X and Y, when the composition ratios of each monomer unit are Wx and Wy (mass %), the molecular weights are Mx and My, the evaporation energies are Δei(X), Δei(Y), and the molar volumes are Δvi(X), Δvi(Y), the molar ratios (j) of each monomer unit are Wx / Mx and Wy / My respectively, and the SP value (σp) of this resin is as follows. σp=[{(Wx / Mx)×Δei(X)+Wy / My×Δei(Y)} / {(Wx / Mx)×Δvi(X)+Wy / My×Δvi(Y)}] 0.5 When two or more types of resins are further mixed, the SP value (σM) of the mixture is calculated as the product of the mass composition ratio (Wi) of the mixture and the SP value (σi) of each resin, and is expressed by the following formula. σM=Σ(Wi×σi)

[0104] <Calculation of the coating rate of the shell, method for observing the second shell> The ratio (coating rate) at which the shell of the toner is observed can be determined by measuring the cross-sectional shape of a single toner particle. The specific method for measuring the cross-sectional shape of a single toner particle is as follows. First, the toner is sufficiently dispersed in a photocurable epoxy resin, and then irradiated with ultraviolet rays to cure the epoxy resin. The obtained cured product is cut using a microtome equipped with a diamond blade to prepare a sample in the form of a thin slice with a thickness of 100 nm. After staining the above sample with ruthenium tetroxide, a transmission electron microscope (TEM) (trade name: electron microscope Tecnai TF20XT, manufactured by FEI Company) is used to observe the cross-section of the toner under the condition of an acceleration voltage of 120 kV to obtain a TEM image. At this time, as the cross-section of the toner, in accordance with the method for measuring the number average particle diameter (D1) of the toner described later, a cross-section having a major axis diameter that is 0.9 times to 1.1 times the number average particle diameter (D1) when measuring the same toner is selected. In the above-described observation method, the amorphous resin in the toner particles is strongly stained with ruthenium tetroxide. As a result, the shell portion mainly composed of the amorphous resin is stained, and the core portion mainly composed of the non-stained crystalline resin can be observed as a contrast. The observation magnification is set to 20,000 times. Based on the obtained TEM image, in the cross-section of a single toner particle, the length C1 (nm) of the portion where the shell is observed out of the length (perimeter) of the outer periphery of a single toner particle and the length C2 (nm) of the outer periphery (perimeter) of a single toner particle are calculated, and C1 / C2×100 (%) is defined as the coating rate of the shell (the ratio at which the shell is observed). This measurement is performed on 100 toner particles, and the arithmetic mean value thereof is adopted. When the second shell is present, it is observed that a shell exists further on the outer periphery of the shell of the amorphous resin.

[0105] (Identification of the Second Shell) The second shell can be identified by performing elemental analysis on the surface of toner particles. Hereinafter, examples of the case where the second shell is an organosilicon polymer and the case where it is a melamine resin will be described. [Method for Identifying Organosilicon Polymer] The identification of the organosilicon polymer can be carried out by combining SEM observation and elemental analysis by EDS. Using a scanning electron microscope "S-4800" (trade name; manufactured by Hitachi, Ltd.), observe the toner particles in a field of view magnified up to 50,000 times. Perform EDS analysis focusing on the surface of the toner particles, and determine whether it is an organosilicon polymer based on the presence or absence of the Si element peak. When both the organosilicon polymer and silica are contained, the organosilicon polymer is identified by comparing the ratio (Si / O ratio) of the elemental contents (atomic%) of Si and O with that of a reference sample. Perform EDS analysis on the reference samples of the organosilicon polymer and silica respectively under the same conditions to obtain the elemental contents (atomic%) of Si and O respectively. Let the Si / O ratio of the organosilicon polymer be A and the Si / O ratio of the silica fine particles be B. Select the measurement conditions under which A becomes significantly larger than B.

[0106] Specifically, perform 10 measurements on the reference sample under the same conditions to obtain the additive average values of A and B respectively. Select the measurement conditions under which the obtained average value satisfies A / B > 1.1. Judge that it is an organosilicon polymer when the Si / O ratio of the fine particles to be discriminated is on the A side of [(A + B) / 2]. Commercially available products can be used as the reference samples of the organosilicon polymer. Examples of commercially available products include Tospearl 120A (Momentive Performance Materials Japan G.K.). Examples of commercially available products of the silica reference sample include HDK V15 (Asahi Kasei).

[0107] [Method for Identifying Melamine] Melamine can also be identified in the same way as the organosilicon polymer. Prepare a standard sample of melamine, perform EDS analysis on the standard sample and toner particles under the same conditions, and identify melamine based on the ratio of C to N. As the standard sample of melamine, commercially available melamine resin products can also be used. Examples of commercially available products include MM-A (Panasonic Industry Co., Ltd.). 。

[0108] <Measurement method of viscoelasticity> The viscoelasticity is measured using a viscoelasticity measuring device (rheometer) ARES (manufactured by Rheometrics Scientific). The general outline of the measurement is described in the ARES operation manual 902-30004 (August 1997 edition), 902-00153 (July 1993 edition) issued by Rheometrics Scientific, and is as follows. · Measuring jig: torsion rectangular · Measurement sample: For toner, use a compression molding machine to produce a rectangular parallelepiped sample with a width of 12 mm, a height of 20 mm, and a thickness of 2.5 mm (maintain 25 kN for 30 minutes at room temperature). The compression molding machine used is the 100 kN press NT-100H manufactured by NPa Systems Co., Ltd.

[0109] After leaving the jig and sample at room temperature (23 °C) for 1 hour, attach the sample to the jig. Refer to Figure 2. Fix it so that the width of the measurement part is 12.0 mm, the thickness is 2.5 mm, and the height is 10.0 mm as shown in the figure. After adjusting the temperature to 30 °C over 10 minutes, perform the measurement with the following settings. · Measurement frequency: 6.28 rad / s · Setting of measurement strain: Set the initial value to 0.1% and perform the measurement in the automatic measurement mode · Elongation correction of sample: Adjust in the automatic measurement mode · Measurement temperature: Heat up from 30 °C to 150 °C at a rate of 2 °C per minute · Measurement interval: Measure the viscoelasticity data every 30 seconds, that is, every 1 °C Data is transferred through an interface to the RSI Orchesrator (control, data collection, and analysis software, manufactured by Rheometrics Scientific) operating on Microsoft's Windows (registered trademark) 2000. Among the measurement data, let the temperature at which the storage modulus G' becomes 1.0×10 8 Pa be T1 [°C].

[0110] <Method for Measuring Acid Value> The acid value is the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of the sample. The acid value of the resin is measured according to JIS K 0070-1992. Specifically, it is measured according to the following procedure. (1) Preparation of Reagents Dissolve 1.0 g of phenolphthalein in 90 mL of ethyl alcohol (95% by volume), add ion-exchanged water to make 100 mL, and obtain a phenolphthalein solution. Dissolve 7 g of special-grade potassium hydroxide in 5 mL of water, add ethyl alcohol (95% by volume) to make 1 L. Put it in an alkali-resistant container so as not to contact carbon dioxide gas, etc., leave it for 3 days, and then filter to obtain a potassium hydroxide solution. The obtained potassium hydroxide solution is stored in an alkali-resistant container. The factor of the potassium hydroxide solution is determined from the amount of the potassium hydroxide solution required for neutralization by taking 25 mL of 0.1 mol / L hydrochloric acid in an Erlenmeyer flask, adding several drops of the phenolphthalein solution, and titrating with the potassium hydroxide solution. The 0.1 mol / L hydrochloric acid used is prepared according to JIS K 8001-1998.

[0111] (2) Operation (A) This Test Precisely weigh 2.0 g of the sample (for example, crystalline vinyl resin (A)) into a 200 mL Erlenmeyer flask, add 100 mL of a toluene / ethanol (2:1) mixed solution, and dissolve it over 5 hours. Next, add several drops of the phenolphthalein solution as an indicator and titrate with the potassium hydroxide solution. The end point of the titration is when the light red color of the indicator persists for 30 seconds. (B) Blank test Perform titration in the same manner as the above operation, except that no sample is used (i.e., only a mixed solution of toluene / ethanol (2:1) is used). (3) Substitute the obtained result into the following formula to calculate the acid value. A = [(C - B) × f × 5.61] / S Here, A: acid value (mgKOH / g), B: amount of potassium hydroxide solution added in the blank test (mL), C: amount of potassium hydroxide solution added in this test (mL), f: factor of potassium hydroxide solution, S: mass of sample (g).

[0112] <Measurement of number average particle diameter (D1) of toner> The number average particle diameter (D1) of the toner is calculated as follows. As the measuring device, use a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) by the pore electrical resistance method equipped with a 100 μm aperture tube. For the setting of measurement conditions and the analysis of measurement data, use the attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). The measurement is performed with an effective number of measurement channels of 25,000 channels. The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water so that the concentration becomes 1.0%. For example, "ISOTON II" (manufactured by Beckman Coulter, Inc.) can be used. Before performing measurement and analysis, set the dedicated software as follows. On the "Change Standard Measurement Method (SOMME)" screen of the dedicated software, set the total count number in the control mode to 50,000 particles, the number of measurements to 1 time, and set the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter, Inc.). By pressing the "Measurement Button for Threshold / Noise Level", the threshold and noise level are automatically set. Also, set the current to 1,600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush of Aperture Tube after Measurement". On the "Conversion Setting from Pulse to Particle Size" screen of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm to 60 μm. The specific measurement method is as follows.

[0113] (1) Put 200.0 mL of the electrolytic aqueous solution into a 250 mL round-bottom glass beaker dedicated to Multisizer 3, set it on the sample stand, and stir with a stirrer rod counterclockwise at 24 revolutions per second. Then, use the "Flush of the Aperture Tube" function of the dedicated software to remove dirt and bubbles in the aperture tube. (2) Put 30.0 mL of the electrolytic aqueous solution into a 100 mL flat-bottom glass beaker. Add 0.3 mL of a dilution obtained by diluting "Contaminon N" (a 10% aqueous solution of a neutral detergent for precision measuring instruments with pH 7 composed of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water as a dispersant. (3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetra150" (manufactured by Nikkaki Bios Co., Ltd.) with two oscillators with an oscillation frequency of 50 kHz built in with a 180-degree phase shift and an electrical output of 120 W. Put 3.3 L of ion-exchanged water into the water tank of the ultrasonic disperser, and add 2.0 mL of Contaminon N to this water tank. (4) Set the beaker in (2) above in the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height position of the beaker so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker in (4) above with ultrasonic waves, add 10 mg of toner little by little to the electrolytic aqueous solution and disperse it. Then, continue the ultrasonic dispersion treatment for another 60 seconds. Note that during ultrasonic dispersion, appropriately adjust the water temperature of the water tank to be 10°C or higher and 40°C or lower. (6) Using a pipette, the electrolytic aqueous solution (5) in which toner particles are dispersed is dropped into the round-bottomed beaker (1) placed in the sample stand, and adjusted so that the measurement concentration becomes 5%. Then, the measurement is performed until the number of measured particles reaches 50,000. (7) Analyze the measurement data using the dedicated software attached to the device, and calculate the number average particle size (D1). When set to graph / volume% in the dedicated software, the "average diameter" on the "Analysis / Volume Statistical Value (Arithmetic Mean)" screen is the weight average particle size (D4), and when set to graph / count% in the dedicated software, the "average diameter" on the "Analysis / Count Statistical Value (Arithmetic Mean)" screen is the number average particle size (D1).

Example

[0114] Hereinafter, the present disclosure will be specifically described by way of examples, but these do not limit the present disclosure in any way. In the following formulations, parts are based on mass unless otherwise specified.

[0115] (Preparation of polymerizable monomer (a-1)) Into a pressurized reaction vessel equipped with a stirring device, a temperature control device, a thermometer, an air introduction tube, a pressure reduction device, and a water reduction device, 727.0 parts of cetanol, 175.0 parts of fumaric acid, 2.5 parts of dibutyltin oxide, and 1 part of 2,6-di-tert-butyl-p-cresol were charged, and stirred at 120 °C for homogenization. Then, the temperature was raised to 165 °C, and esterification under reduced pressure was carried out while removing the distillate water at 21 kPa for 3 hours. After confirming that the acid value was less than 30.0 mgKOH / g, esterification under reduced pressure was carried out while removing the distillate water at 3 kPa or less for 12 hours. This was taken out to obtain a polymerizable monomer (a-1).

[0116] (Preparation of polymerizable monomers (a-2) to (a-10)) Polymerizable monomers (a-2) to (a-10) were produced in the same manner as in the preparation example of the polymerizable monomer (a-1), except that the types and added parts of the raw materials were changed as shown in Table 1. The compositions of the polymerizable monomers (a-2) to (a-10) are shown in Table 1.

[0117]

Table 1

[0118] (Preparation of Crystalline Vinyl Resin (A-1)) 120.0 parts of xylene and 80.0 parts of polymerizable monomer (a-1) were charged into an autoclave. After heating to 135 °C with stirring under a sealed state, the pressure was released, and then the temperature was raised to 155 °C with stirring under a sealed state. A mixed solution of 14.0 parts of methacrylonitrile, 6.0 parts of styrene, 1.6 parts of di-t-butyl peroxide, and 60.0 parts of xylene was added dropwise over 3 hours while controlling the temperature inside the autoclave to be 155 °C to carry out polymerization. After the dropwise addition, the dropping line was washed with 20.0 parts of xylene. Further, after holding at the same temperature for 2.2 hours, it was cooled to 70 °C, and then 12.8 parts of di-t-butyl peroxide was added and reacted. Thereafter, the solvent was removed under reduced pressure of 0.5 to 2.5 kPa at 170 °C for 3 hours to obtain crystalline vinyl resin (A-1). It was confirmed that crystalline vinyl resin (A-1) is a crystalline resin showing a distinct endothermic peak in differential scanning calorimetry (DSC) measurement.

[0119] (Preparation of Crystalline Vinyl Resins (A-2) to (A-22)) In the production of crystalline vinyl resin (A-1), except that the types and addition amounts of raw materials were changed as shown in Table 2, crystalline vinyl resins (A-2) to (A-22) were produced in the same manner. It was confirmed that crystalline vinyl resins (A-2) to (A-22) are crystalline resins showing a distinct endothermic peak in differential scanning calorimetry (DSC) measurement. The compositions and physical property values of crystalline vinyl resins (A-2) to (A-22) are shown in Table 2.

[0120]

Table 2

[0121] (Preparation of resin for shell (S1)) The following materials were added into an autoclave equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device. · 25.3 parts of terephthalic acid · 74.7 parts of bisphenol A-propylene oxide 2-mol adduct · 0.02 part of potassium titanium oxalate (catalyst) Subsequently, the reaction was carried out at 220 °C under normal pressure in a nitrogen atmosphere. After cooling down the temperature, it was pulverized to obtain a resin for shell (S1) (amorphous polyester (amorphous PES)).

[0122] (Preparation of resins for shell (S2), (S3), (S4)) The following materials were charged into a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube under a nitrogen atmosphere. · 100.0 parts of solvent toluene · 74.0 parts of styrene · 9.0 parts of acrylonitrile · 8.0 parts of methacrylic acid · 9.0 parts of 2-hydroxyethyl methacrylate · 5.0 parts of polymerization initiator t-butylperoxypivalate (manufactured by NOF Corporation: PERBUTYL PV) While stirring the inside of the above reaction vessel at 200 rpm, it was heated to 70 °C and subjected to a polymerization reaction for 12 hours to obtain a solution in which the polymer of the monomer composition was dissolved in toluene. Subsequently, after cooling down the above solution to 25 °C, the above solution was charged into 1000.0 parts of methanol while stirring to precipitate a methanol-insoluble component. The obtained methanol-insoluble component was filtered off, further washed with methanol, and then vacuum dried at 40 °C for 24 hours to obtain a resin for shell (S2). In addition, resins for shell (S3) and (S4) were obtained by the same production method except that the raw material composition of the resin for shell (S2) was changed as shown in Table 3.

[0123] (Preparation of Resin for Shell (S5)) The following materials were added into an autoclave equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device. · Sebacic acid 64.2 parts · 1,6 - Hexanediol 35.8 parts · Potassium titanium oxalate (catalyst) 0.06 part Subsequently, the reaction was carried out at 220 °C under normal pressure in a nitrogen atmosphere. After cooling, it was pulverized to obtain a resin for shell (S5) (crystalline polyester (crystalline PES)).

[0124]

Table 3

[0125] <Example 1> (Manufacture of Toner Particle 1) · n - Butyl acrylate (denoted as BA in the table) 20.0 parts · Styrene 30.0 parts · Colorant Pigment Blue 15:3 6.5 parts A mixture composed of the above materials was prepared. The above mixture was put into an attritor (manufactured by Nippon Coke Co., Ltd.), and using zirconia beads with a diameter of 5 mm, it was dispersed at 200 rpm for 2 hours to obtain a raw material dispersion liquid.

[0126] On the other hand, 735.0 parts of ion - exchanged water and 16.0 parts of trisodium phosphate (dodecahydrate) were added to a container equipped with a high - speed stirring device homomixer (manufactured by Primix Co., Ltd.) and a thermometer, and the temperature was raised to 60 °C while stirring at 12000 rpm. An aqueous calcium chloride solution in which 9.0 parts of calcium chloride (dihydrate) was dissolved in 65.0 parts of ion - exchanged water was added thereto, and it was stirred at 12000 rpm for 30 minutes while maintaining 60 °C. 10% hydrochloric acid was added thereto to adjust the pH to 6.0, and an aqueous medium in which an inorganic dispersion stabilizer containing hydroxyapatite was dispersed in water was obtained.

[0127] Subsequently, the above raw material dispersion was transferred to a container equipped with a stirrer and a thermometer, and the temperature was raised to 60°C while stirring at 100 rpm. · 50.0 parts of crystalline vinyl resin (A3) · 9.0 parts of mold release agent (DP18) DP18 (dipentaerythritol stearate wax, melting point 79°C, manufactured by Nisshin OilliO Group, Ltd.) · 6.0 parts of shell resin (S1) The above materials were added thereto, and after stirring at 100 rpm for 30 minutes while maintaining 60°C, 5.0 parts of t-butyl peroxy pivalate (manufactured by NOF Corporation: Perbutyl PV) as a polymerization initiator was added and stirred for another 1 minute, and then it was put into an aqueous medium being stirred at 12,000 rpm by the above high-speed stirrer. Stirring was continued at 12,000 rpm for 20 minutes by the above high-speed stirrer while maintaining 60°C to obtain a granulation liquid.

[0128] The above granulation liquid was transferred to a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube, and the temperature was raised to 70°C while stirring at 150 rpm under a nitrogen atmosphere. A polymerization reaction was carried out at 150 rpm for 12 hours while maintaining 70°C. During the period until solidification in the polymerization reaction, materials with high polarity exist on the water side and materials with low polarity exist on the inner side. Therefore, the shell resin forms a shell outside the toner particles, and the other materials become the core existing inside the toner particles. The obtained dispersion was cooled to 55°C while stirring at 150 rpm.

[0129] (Second shell formation step) 〇 Hydrolysis step of the second shell-forming organosilicon compound As a pretreatment for the formation of the second shell, the following was carried out in parallel with the polymerization reaction. 60.0 parts of ion-exchanged water was weighed into a reaction vessel equipped with a stirrer and a thermometer, and the pH was adjusted to 3.0 using 10 mass% hydrochloric acid. This was heated while stirring to a temperature of 55°C. Thereafter, 40.0 parts of methyltriethoxysilane (MTES), an organosilicon compound for the surface layer, was added to carry out a hydrolysis reaction. The end point of hydrolysis was confirmed visually by the fact that the oil and water did not separate and became a single layer, and it was cooled to obtain a hydrolysis solution of the organosilicon compound for the surface layer.

[0130] 〇Formation of the second shell While continuing to stir the dispersion obtained in the polymerization step at 55°C, 20.0 parts of the hydrolysis solution of the organosilicon compound for the surface layer was added to start the formation of the toner surface layer. It was held for 30 minutes as it was. After holding for 30 minutes, the slurry was adjusted to pH = 9.0 for condensation completion using an aqueous sodium hydroxide solution and held for a further 300 minutes to form a second shell, obtaining a toner particle dispersion. The obtained toner particle dispersion was cooled to 30°C while stirring at 150 rpm. Thereafter, dilute hydrochloric acid was added until the pH reached 1.5 while maintaining stirring to dissolve the dispersion stabilizer. The solid content was filtered off, washed thoroughly with ion-exchanged water, and then vacuum dried at 30°C for 24 hours to obtain toner particles 1.

[0131] (Preparation and evaluation of toner 1) To 100.0 parts of the above toner particles 1, 2.0 parts of silica fine particles (hydrophobized with hexamethyldisilazane, number average particle diameter of primary particles: 10 nm, BET specific surface area: 170 m 2 / g) was added and mixed using a Henschel mixer (manufactured by Nippon Coke Co., Ltd.) at 3000 rpm for 15 minutes to obtain toner 1. The obtained toner 1 was evaluated by the method shown below. The physical properties of the toner are shown in Table 4, and the evaluation results are shown in Table 5.

[0132] <Toner evaluation method> <Low-temperature fixing property> The process cartridge filled with the evaluation toner was left standing for 48 hours in a normal temperature and humidity environment (temperature: 23°C, relative humidity: 50%). Using the LBP-712Ci modified to operate even without the fuser, an unfixed image of an image pattern with 9-point evenly arranged 10 mm × 10 mm square images across the entire transfer paper was output. The toner loading amount on the transfer paper was 0.80 mg / cm 2 and the fixing start temperature was evaluated. The transfer paper used was A4 paper (“Prober Bond Paper”: 105 g / m 2 , manufactured by Fox River). As the fuser, the fuser of the LBP-712Ci was removed externally, and an external fuser modified to operate even outside the laser beam printer was used. The external fuser increased the fixing temperature in 5°C increments from 90°C and performed fixing under the condition of a process speed of 260 mm / sec. The fixed image was visually confirmed, and the lowest temperature at which cold offset did not occur was evaluated as the fixing start temperature. The evaluation results are shown in Table 5.

[0133] <Evaluation of heat-resistant storage stability (blocking resistance)> 10 g of the evaluation toner was placed in a 100 mL resin cup and left standing for 7 days in an environment of temperature 45°C and relative humidity 95%. Then, the degree of occurrence of aggregates was visually confirmed, and the heat-resistant storage stability was evaluated according to the following criteria. The evaluation results are shown in Table 5. (Evaluation criteria) A: No aggregates are visible. B: Aggregates are visible but easily break up. C: Aggregates are visible but break up when shaken. D: Aggregates can be grasped and do not break up easily.

[0134] <Evaluation of charge decay rate coefficient> (Measurement method of charge decay rate coefficient) The charge decay rate coefficient, which is an index of charge retention, is measured using an electrostatic diffusion rate measuring device NS-D100 (manufactured by Nano Seeds). First, fill the sample pan with about 100 mg of toner as a sample and rub it to make the surface smooth. Irradiate the sample pan with X-rays for 30 seconds using an X-ray discharger to discharge the charge of the sample. Place the discharged sample pan on the measurement plate. At the same time, place a metal plate as a reference for the 0 correction of the surface potentiometer. The measurement plate with the sample placed on it is left in an environment of 30°C and 80% RH for 1 hour or more before measurement. Set the measurement conditions as follows. Charge time: 0.1 second Measurement time: 1800 seconds Measurement interval: 1 second Discharge polarity: - Electrode: Yes Set the initial potential to -600 V and measure the change in surface potential immediately after charging. The charge decay rate coefficient α is obtained by fitting the obtained results to the following formula. V t = V0exp(-αt 1 / 2 ) V t : Surface potential (V) at time t V0: Initial surface potential (V) t: Time (seconds) after the application of charge α: Charge decay rate coefficient

[0135] (Heat cycle test assuming cargo ship transportation) When the product is transported by sea on a cargo ship, in a situation where temperature and humidity are not controlled, such as in a dry container, it may be exposed to an environment with a large temperature and humidity difference between day and night depending on the region and situation. Therefore, this condition was set. For the heat cycle test, 100 g of the toner to be evaluated was placed in a 500 ml sample (R) polycup (manufactured by Sampura Tech Co., Ltd.). Next, this polycup containing the toner was placed in a thermo-hygrostat IX210 (manufactured by Yamato Scientific Co., Ltd.), and a heat cycle test assuming dry container cargo ship transportation was carried out. The specific conditions were first to hold at a temperature of 30°C and a humidity of 70% RH for 18 hours, then change the temperature to 50°C and the humidity to 55% RH over 2 hours and hold for 2 hours. Next, change the temperature to 30°C and the humidity to 70% RH over 2 hours. This heat cycle was repeated 20 times. The above temperature and humidity changes are illustrated in Figure 1. For each of the obtained toners, the charge decay rate coefficient was measured before the post-production heat cycle, after 10 heat cycles, and after 20 heat cycles, and the values are shown in Table 5.

[0136] [Table 4] In the table, the ratio I indicates the content ratio of the crystalline vinyl resin (A) based on the mass of the binder resin.

[0137] [Table 5]

[0138] <Examples 2 to 28, Comparative Examples 1 to 8> In Example 1, toner particles 2 to 28 and comparative toner particles 1 to 8 were obtained in the same manner except that the materials used and the addition amounts were changed as shown in Tables 1, 2, 3, and 6. Note that in the production of toner particles 27 and comparative toner particles 1, the second shell formation step was not performed. Further, after the second shell formation step of toner particles 28, the following was carried out.

[0139] (After the second shell formation of toner particles 28) While continuing to stir the dispersion obtained in the polymerization step at 55 °C, the inside of the reaction vessel was adjusted to pH 4 with a 1 mol / L aqueous solution of p-toluenesulfonic acid. 6 parts of an aqueous solution of a hexamethylolmelamine prepolymer (Milbren resin SM-607 (solid content concentration: 80% by mass); manufactured by Showa Denko KK) was added to this solution. While continuing to stir at 150 rpm, the temperature was raised to 70 °C and held for 2 hours to form a second shell, and a toner particle dispersion was obtained. The obtained toner particle dispersion was cooled to 30 °C while stirring at 150 rpm. Thereafter, while maintaining the stirring, dilute hydrochloric acid was added until the pH reached 1.5 to dissolve the dispersion stabilizer. The solid content was filtered off, washed thoroughly with ion-exchanged water, and then vacuum-dried at 30 °C for 24 hours to obtain toner particles 28.

[0140] Furthermore, external addition was carried out in the same manner as in Example 1 to obtain Toners 2 to 28 and Comparative Toners 1 to 8. The physical properties of the toners are shown in Table 4, and the evaluation results are shown in Table 5. When the obtained toners were analyzed by the method described above, values of ratio J and ratio K similar to those in Table 2 were obtained.

[0141]

Table 6

[0142] As is clear from Table 5, Examples 1 to 28 have excellent low-temperature fixability and heat-resistant storage properties compared to Comparative Examples 1 to 8, and even when exposed to an environment where a large temperature and humidity change occurs, the change in chargeability is less likely to occur.

[0143] The present disclosure relates to the following configuration. (Configuration 1) A toner containing toner particles, The toner particles have a core containing a binder resin, and a shell covering the core, The binder resin contains a crystalline vinyl resin (A), The crystalline vinyl resin (A) contains 5.0 mass% or more of a monomer unit (a) represented by the following formula (1) based on the mass of the crystalline vinyl resin (A), TIFF2025094764000012.tif27153 In the formula (1), R 1 ~R 4 Among them, at least two are each independently -X-COOR 5 and the rest are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, X is a single bond or an alkylene group having 1 or 2 carbon atoms, and R 5 is an alkyl group having 16 to 30 carbon atoms, The shell is an amorphous resin, The SP value of the amorphous resin is SP S (J / cm 3 ) 0.5and the SP value of the crystalline vinyl resin (A) is SP A (J / cm 3 ) 0.5 When it is the SP S and SP A satisfy |SP S - SP A | ≦ 5.0. A toner characterized by this. (Configuration 2) In the viscoelasticity measurement of the toner, when the storage elastic modulus G' of the toner is 1.0 × 10 8 Pa, the temperature is T1 (°C), the toner according to Configuration 1, wherein the T1 satisfies 40.0 ≦ T1 ≦ 70.0. (Configuration 3) The toner according to Configuration 1 or 2, wherein the binder resin contains 20.0% by mass or more of the crystalline vinyl resin (A) based on the mass of the binder resin. (Configuration 4) The toner according to any one of Configurations 1 to 3, wherein the crystalline vinyl resin (A) contains 30.0% by mass or more of the monomer unit (a) based on the mass of the crystalline vinyl resin (A). (Configuration 5) In the crystalline vinyl resin (A), among the monomer units having an alkyl group with 16 to 30 carbon atoms including the monomer unit (a), the content ratio of the monomer unit (a) is 50.0 to 100.0% by mass. The toner according to any one of Configurations 1 to 4. (Configuration 6) The toner according to any one of Configurations 1 to 5, wherein the acid value of the crystalline vinyl resin (A) is 3.0 mgKOH / g or less. (Configuration 7) The crystalline vinyl resin (A) contains, in addition to the monomer unit (a), a monomer unit (b) different from the monomer unit (a), The SP value of the monomer unit (a) is SPa (J / cm 3 ) 0.5 and the SP value of the monomer unit (b) is SPb (J / cm 3 ) 0.5 When it is The SPa and SPb satisfy the following formula (2): 3.0 ≦ |SPb - SPa| ≦ 21.0 ···(2) The toner according to any one of Configurations 1 to 6. (Configuration 8) In an image obtained by observing a cross-section of the toner with a transmission electron microscope, the shell is observed over 70.0% or more of the outer peripheral length of the core. The toner according to any one of Configurations 1 to 7. - (Configuration 9) The toner according to any one of Configurations 1 to 8, wherein the shell contains at least one selected from the group consisting of an amorphous polyester resin and an amorphous vinyl resin. (Configuration 10) In an image obtained by observing a cross-section of the toner with a transmission electron microscope, the toner particles further have a second shell that covers the shell and is different from the shell. The toner according to any one of Configurations 1 to 9. (Configuration 11) The toner according to Configuration 10, wherein the second shell is an organosilicon polymer. (Configuration 12) The toner according to any one of Configurations 1 to 11, wherein the binder resin further contains an amorphous vinyl resin (B).

Claims

1. A toner containing toner particles, wherein the toner particles have: a core containing a binder resin, and a shell covering the core, the binder resin contains a crystalline vinyl resin (A), the crystalline vinyl resin (A) contains 5.0% by mass or more of a monomer unit (a) represented by the following formula (1) based on the mass of the crystalline vinyl resin (A), In the formula (1), R １ ~R ４ Among them, at least two are each independently -X-COOR ５ , and the rest are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, X is a single bond or an alkylene group having 1 or 2 carbon atoms, and R ５ is an alkyl group having 16 to 30 carbon atoms, the shell is an amorphous resin, Let the SP value of the amorphous resin be SP Ｓ (J / cm ３ ) ０．５ and let the SP value of the crystalline vinyl resin (A) be SP Ａ (J / cm ３ ) ０．５ When this is done, The SP Ｓ and SP Ａ satisfy |SP Ｓ - SP Ａ | ≤ 5.0 and the toner is characterized by the above.

2. In the measurement of the viscoelasticity of the toner, when the storage elastic modulus G' of the toner is 1.0×10 ８ Pa, the temperature at that time is defined as T1 (°C), The toner according to Claim 1, wherein T1 satisfies 40.0 ≦ T1 ≦ 70.

0.

3. The toner according to Claim 1 or 2, wherein the binder resin contains 20.0% by mass or more of the crystalline vinyl resin (A) based on the mass of the binder resin.

4. The toner according to Claim 1 or 2, wherein the crystalline vinyl resin (A) contains 30.0% by mass or more of the monomer unit (a) based on the mass of the crystalline vinyl resin (A).

5. The toner according to Claim 1 or 2, wherein in the crystalline vinyl resin (A), among the monomer units having an alkyl group with 16 to 30 carbon atoms including the monomer unit (a), the content ratio of the monomer unit (a) is 50.0 to 100.0% by mass.

6. The toner according to Claim 1 or 2, wherein the acid value of the crystalline vinyl resin (A) is 3.0 mgKOH / g or less.

7. The crystalline vinyl resin (A) contains, in addition to the monomer unit (a), a monomer unit (b) different from the monomer unit (a), and Spa and Spb satisfy the following formula (2): Let the SP value of the monomer unit (a) be SPa (J / cm ３ ), ０．５ and when the SP value of the monomer unit (b) is SPb (J / cm ３ ), ０．５ then 3.0 ≦ |Spb - Spa| ≦ 21.0... (2) The toner according to Claim 1 or 2.

8. The toner according to Claim 1 or 2, wherein in an image obtained by observing a cross-section of the toner with a transmission electron microscope, the shell is observed over 70.0% or more of the outer peripheral length of the core.

9. The toner according to Claim 1 or 2, wherein the shell contains at least one selected from the group consisting of an amorphous polyester resin and an amorphous vinyl resin.

10. The toner according to Claim 1 or 2, wherein in an image obtained by observing a cross-section of the toner with a transmission electron microscope, the toner particles further have a second shell that covers the shell and is different from the shell.

11. The toner according to Claim 10, wherein the second shell is an organosilicon polymer.

12. ​ The toner according to claim 1 or 2, wherein the binder resin further contains an amorphous vinyl resin (B).

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