JP2018205668A - Liquid developer - Google Patents

Abstract

To provide a liquid developer that has excellent low-temperature fixability, even when stored in a resin film, prevents the occurrence of deformation of the resin film, and is not easily dried.SOLUTION: A liquid developer contains toner particles containing a binder resin and a colorant, dispersant, and insulating liquid, where the insulating liquid contains polybutene and olefin at a mass ratio (polybutene/olefin) of 60/40 or more and 90/10 or less; the olefin contains 16 carbon atoms, and is an internal olefin having an average value of double bond positions of 2 or more, which is calculated from the mass ratio of a double bond distribution.SELECTED DRAWING: None

Description

  The present invention relates to a liquid developer used for developing a latent image formed in, for example, electrophotography, electrostatic recording method, electrostatic printing method and the like.

  Electrophotographic developers include a dry developer that uses a toner component made of a material containing a colorant and a binder resin in a dry state, and a liquid developer in which the toner component is dispersed in an insulating liquid.

  In the liquid developer, since the toner particles are dispersed in the insulating liquid in oil, the particle size can be reduced as compared with the dry developer. Therefore, since a high-quality printed matter that surpasses offset printing can be obtained, it is suitable for commercial printing applications.

  In Patent Document 1, as a liquid developer that is excellent in low-temperature fixability and does not affect the printing apparatus even for a long time operation, toner particles containing a resin containing a polyester and a pigment are insulative in the presence of a dispersant. A liquid developer dispersed in a liquid, wherein the insulating liquid has a boiling point of 300 ° C. or less, and a methyl group peak intensity ratio measured by a Fourier transform infrared spectrophotometer is 25% or more. Agents are disclosed.

JP 2017-45051 A

  When a printed matter printed using a liquid developer is stored in a bag made of a resin film such as a polypropylene film, the resin film may be deformed by the insulating liquid remaining on the image surface. In this case, the use of an insulating liquid having high volatility can suppress the remaining of the insulating liquid, but the liquid developer is easy to dry and causes another problem of solidifying on the developing roller during printing. .

  The present invention relates to a liquid developer that has excellent low-temperature fixability, does not cause deformation of a resin film even when stored in a resin film, and is difficult to dry.

  The inventors of the present invention have studied various insulating liquids that hardly remain on the image surface and do not cause deformation of the resin film. As a result, an insulating liquid in which polybutene and a specific olefin are mixed at a predetermined ratio is effective, and the low temperature The inventors have found that the fixability is also good and have completed the present invention.

  The present invention is a liquid developer containing toner particles containing a binder resin and a colorant, a dispersant, and an insulating liquid, wherein the insulating liquid contains polybutene and olefin in a range of 60/40 to 90/10. The olefin is an internal olefin having 16 carbon atoms and an average value of double bond positions calculated from the mass ratio of the double bond distribution of 2 or more. The present invention relates to a liquid developer.

  The liquid developer of the present invention is excellent in low-temperature fixability, has an excellent effect that it does not cause deformation of the resin film even when stored in the resin film, and is difficult to dry.

  The liquid developer of the present invention contains toner particles and an insulating liquid, and the toner particles contain a binder resin and a colorant.

  The binder resin preferably includes a polyester resin. Examples of the polyester resin include polyester resins and composite resins containing polyester resins and other resins such as styrene resins.

  The polyester resin is preferably a polycondensate of an alcohol component containing a divalent or higher alcohol and a carboxylic acid component containing a divalent or higher carboxylic acid compound.

  Examples of the divalent alcohol include aliphatic diols, preferably aliphatic diols having 2 to 20 carbon atoms, more preferably 2 to 15 carbon atoms, and formula (I):

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y are the average number of moles of alkylene oxide added, each being a positive number, The sum value is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and further preferably 4 or less)
The alkylene oxide adduct of bisphenol A represented by these, bisphenol A, hydrogenated bisphenol A, etc. are mentioned. Specific examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and the like.

  As the alcohol component, an alkylene oxide adduct of bisphenol A represented by the formula (I) is preferable from the viewpoint of low-temperature fixability and grindability. The content of the alkylene oxide adduct of bisphenol A represented by the formula (I) is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, more preferably in the alcohol component. It is 95 mol% or more, more preferably 100 mol%.

  Examples of the divalent carboxylic acid compound include dicarboxylic acids having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, anhydrides thereof, or alkyl groups. Examples thereof include derivatives such as alkyl esters having 1 to 3 carbon atoms. Specific examples of the dicarboxylic acid include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, fumaric acid, maleic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, and alkyl having 1 to 20 carbon atoms. And aliphatic dicarboxylic acids such as succinic acid substituted with a group or an alkenyl group having 2 to 20 carbon atoms.

  The carboxylic acid component is preferably an aromatic dicarboxylic compound and more preferably terephthalic acid from the viewpoint of grindability. The content of the aromatic dicarboxylic acid compound is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, further preferably 95 mol% or more in the carboxylic acid component.

  Examples of the trivalent or higher carboxylic acid compound include 4 to 20 carbon atoms, preferably 6 to 20 carbon atoms, more preferably 7 to 15 carbon atoms, still more preferably 8 to 12 carbon atoms, Preferable examples include trivalent or higher carboxylic acids having 9 to 10 carbon atoms, anhydrides thereof, and derivatives such as alkyl esters having an alkyl group having 1 to 3 carbon atoms. Specific examples include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid), and acid anhydrides thereof.

  The content of the trivalent or higher carboxylic acid compound is preferably 15 mol% or less, more preferably 10 mol% or less in the carboxylic acid component from the viewpoint of low-temperature fixability.

  A monovalent alcohol may be contained in the alcohol component, and a monovalent carboxylic acid compound in the carboxylic acid component may be appropriately contained from the viewpoint of adjusting the molecular weight and softening point of the polyester resin.

  The equivalent ratio (COOH group / OH group) of the carboxylic acid component and the alcohol component in the polyester resin is preferably 0.6 or more, more preferably 0.7 or more, and preferably from the viewpoint of adjusting the softening point of the polyester resin. 1.1 or less, more preferably 1.05 or less.

  The polyester resin is, for example, an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, in the presence of an esterification cocatalyst, a polymerization inhibitor, etc. It can be produced by polycondensation at a temperature of 130 ° C. or higher, more preferably 170 ° C. or higher, and preferably 250 ° C. or lower, more preferably 240 ° C. or lower.

  Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate, and tin compounds are preferred. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. The amount is preferably 1 part by mass or less. Examples of the esterification promoter include gallic acid. The amount of esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. More preferably, it is 0.1 parts by mass or less. Examples of the polymerization inhibitor include t-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Preferably it is 0.1 mass part or less.

  In the present invention, the polyester resin may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of the modified polyester resin include grafting or blocking with phenol, urethane, epoxy or the like by the method described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Among the modified polyester resins, a urethane-modified polyester resin obtained by extending the polyester resin with urethane by a polyisocyanate compound is preferable.

  The softening point of the polyester-based resin is preferably 80 ° C. or higher, more preferably 85 ° C. or higher from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, and improves the low-temperature fixability of the toner. From the viewpoint of achieving this, it is preferably 120 ° C. or lower, more preferably 110 ° C. or lower, and still more preferably 100 ° C. or lower.

  The glass transition temperature of the polyester-based resin is preferably 40 ° C. or higher, more preferably 45 ° C. or higher from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, and improves the low-temperature fixability. From the viewpoint, it is preferably 60 ° C. or lower, more preferably 50 ° C. or lower.

  The acid value of the polyester resin is preferably 3 mgKOH / g or more, more preferably 5 mgKOH / g or more from the viewpoint of adsorption of the dispersant to the toner particles, and preferably from the viewpoint of dispersion stability of the toner particles. Is 20 mgKOH / g or less, more preferably 10 mgKOH / g or less.

  The content of the polyester resin is preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 100% by mass, that is, only the polyester resin is used in the binder resin. However, as long as the effect of the present invention is not impaired, other resins than the polyester resin may be contained. Examples of resins other than polyester resins include styrene resins, epoxy resins, rosin-modified maleic resins, polyethylene resins, polypropylene resins, polyurethane resins, silicone resins, phenol resins, aliphatic or cycloaliphatic carbonization. One type or two or more types selected from resins such as hydrogen resins can be used.

  As the colorant, dyes, pigments and the like used as toner colorants can be used. For example, carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazoero . In the present invention, the toner particles may be either black toner or color toner.

  The content of the colorant is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more, with respect to 100 parts by mass of the binder resin, from the viewpoint of improving the image density. From the viewpoints of improving the pulverization property of the toner and reducing the particle size, improving the low-temperature fixability, and improving the dispersion stability of the toner particles and improving the storage stability, the binder resin 100 mass The amount is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 50 parts by mass or less, and still more preferably 30 parts by mass or less.

  In addition to the binder resin and the colorant, the toner particles include a release agent, a charge control agent, a charge control resin, a magnetic powder, a fluidity improver, a conductivity modifier, a reinforcing filler such as a fibrous substance, and an antioxidant. An additive such as an agent and a cleaning property improver may be appropriately contained.

  As a method for producing toner particles, a toner raw material containing a binder resin and a colorant is melt-kneaded, and the resulting melt-kneaded product is pulverized. An aqueous binder resin dispersion and an aqueous colorant dispersion are used. Examples thereof include a method of mixing and uniting the binder resin particles and the colorant particles, or a method of stirring the aqueous binder resin dispersion and the colorant at high speed. From the viewpoint of improving developability and fixability, a method in which the toner raw material is melt-kneaded and then pulverized is preferable.

  First, the toner raw material containing a binder resin, a colorant, an additive used as necessary is preferably mixed in advance with a mixer such as a Henschel mixer, a super mixer, or a ball mill, and then supplied to a kneader. From the viewpoint of improving the dispersibility of the colorant in the binder resin, a Henschel mixer is more preferable.

  Mixing with a Henschel mixer is carried out while adjusting the peripheral speed of stirring and the stirring time. The peripheral speed is preferably 10 m / sec or more and 30 m / sec or less from the viewpoint of improving the dispersibility of the colorant. The stirring time is preferably 1 minute or more and 10 minutes or less from the viewpoint of improving the dispersibility of the colorant.

  Next, melt kneading of the toner raw material can be performed using a known kneader such as a closed kneader, a uniaxial or biaxial kneader, a continuous open roll type kneader. In the present invention, an open roll kneader is preferable from the viewpoint of improving the dispersibility of the colorant and improving the yield of the toner particles after pulverization.

  Next, after the melt-kneaded product is cooled to such an extent that it can be pulverized, toner particles can be obtained through a pulverization step and, if necessary, a classification step.

  The grinding process may be divided into multiple stages. For example, the melt-kneaded product may be coarsely pulverized to about 1 to 5 mm and further finely pulverized. Moreover, in order to improve the productivity at the time of a grinding | pulverization process, you may grind | pulverize, after mixing melt-kneaded material with inorganic fine particles, such as hydrophobic silica.

  Examples of a pulverizer that is suitably used for coarse pulverization include an atomizer and a rotoplex, but a hammer mill or the like may also be used. Moreover, examples of the pulverizer suitably used for fine pulverization include a fluidized bed jet mill, an airflow jet mill, and a mechanical mill.

  Examples of the classifier used in the classification process include an airflow classifier, an inertia classifier, and a sieve classifier. In addition, you may repeat a grinding | pulverization process and a classification process as needed.

The volume median particle size (D ₅₀ ) of the toner particles obtained in this step is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm from the viewpoint of improving the productivity of the wet pulverization step described later. Below, more preferably 12 μm or less. The volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size. The toner particles are preferably further refined by wet pulverization after mixing with the insulating liquid.

  The content of the toner particles is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, from the viewpoint of high-speed printability with respect to 100 parts by mass of the insulating liquid. From the viewpoint of improving dispersion stability, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, and further preferably 60 parts by mass or less.

The dispersant in the present invention is preferably a basic dispersant having a basic nitrogen-containing group from the viewpoint of high adsorptivity to a resin having an acidic group. Basic nitrogen-containing groups include amino groups (—NH ₂ , —NHR, —NHRR ′), amide groups (—C (═O) —NRR ′), imide groups (—N (COR) ₂ ), and nitro groups. (—NO ₂ ), imino group (═NH), cyano group (—CN), azo group (—N═N—), diazo group (═N ₂ ), and azide group (—N ₃ ) At least one selected is preferred. Here, R and R ′ represent a hydrocarbon group having 1 to 5 carbon atoms. From the viewpoint of the adsorptivity of the dispersant to the toner particles, amino groups and / or imino groups are preferable, and from the viewpoint of chargeability of the toner particles, imino groups are more preferable.

  Examples of the functional group other than the basic nitrogen-containing group include a hydroxy group, a formyl group, an acetal group, an oxime group, and a thiol group.

  The proportion of the basic nitrogen-containing group in the basic dispersant is preferably 70% by number or more, more preferably 80% by number or more, and still more preferably 90% by number in terms of the number of heteroatoms from the viewpoint of dispersion stability. More preferably, it is 95% by number or more, more preferably 100% by number.

  From the viewpoint of dispersibility of the liquid developer, the basic dispersant is a hydrocarbon having 16 or more carbon atoms, a hydrocarbon having 16 or more carbon atoms partially substituted with a halogen atom, and 16 carbon atoms having a reactive functional group. Polymers of the above hydrocarbons, polymers of hydroxycarboxylic acids having 16 or more carbon atoms, polymers of dibasic acids having 2 to 22 carbon atoms and diols having 2 to 22 carbon atoms, alkyl (meth) acrylates having 16 or more carbon atoms It preferably contains a group derived from a polymer, polyolefin or the like (hereinafter also referred to as “dispersible group”).

  The hydrocarbon having 16 or more carbon atoms is preferably a hydrocarbon having 16 to 24 carbon atoms, and examples thereof include hexadecene, octadecene, eicosane and docosane.

  The hydrocarbon having 16 or more carbon atoms partially substituted with a halogen atom is preferably a hydrocarbon having 16 to 24 carbon atoms partially substituted with a halogen atom. For example, chlorohexadecane, bromohexadecane, chlorooctadecane, bromo Examples include octadecane, chloroeicosane, bromoeicosane, chlorodocosane, and bromodocosane.

  The hydrocarbon having 16 or more carbon atoms having a reactive functional group is preferably a hydrocarbon having 16 to 24 carbon atoms having a reactive functional group, such as hexadecenyl succinic acid and octadecenyl succinic acid. Examples include acids, eicosenyl succinic acid, dococenyl succinic acid, hexadecyl glycidyl ether, octadecyl glycidyl ether, eicosyl glycidyl ether, and docosyl glycidyl ether.

  The polymer of hydroxycarboxylic acid having 16 or more carbon atoms is preferably a polymer of hydroxycarboxylic acid having 16 to 24 carbon atoms, and examples thereof include a polymer of 18-hydroxystearic acid.

  Examples of the polymer of a dibasic acid having 2 to 22 carbon atoms and a diol having 2 to 22 carbon atoms include, for example, a polymer of ethylene glycol and sebacic acid, a polymer of 1,4-butanediol and fumaric acid, 1 1,6-hexanediol and fumaric acid polymer, 1,10-decanediol and sebacic acid polymer, 1,12-dodecanediol and 1,12-dodecanedioic acid polymer, and the like.

  As the polymer of alkyl (meth) acrylate having 16 or more carbon atoms, a polymer of alkyl (meth) acrylate having 16 to 24 carbon atoms is preferable. For example, a polymer of hexadecyl methacrylate, a polymer of octadecyl methacrylate, Examples thereof include a polymer of silmethacrylate.

  Examples of the polyolefin include polyethylene, polypropylene, polybutylene, polyisobutene, polymethylpentene, polytetradecene, polyhexadecene, polyoctadecene, polyeicosene, polydocosene and the like.

  The basic dispersant preferably has a polyolefin skeleton from the viewpoint of dispersibility of the toner particles, more preferably has a polypropylene skeleton and / or a polyisobutene skeleton, and from the viewpoint of solubility of the dispersant in the carrier, the polyisobutene. More preferably, it has a skeleton. Accordingly, among the dispersible groups, a group derived from polyolefin is preferable, a group derived from polypropylene and / or a group derived from polyisobutene is more preferable, and a group derived from polyisobutene is more preferable.

  The basic dispersant is not particularly limited, and can be obtained, for example, by reacting a basic nitrogen-containing group material and a dispersible group material.

  Examples of the basic nitrogen-containing group material include polyalkyleneimines such as polyethyleneimine, polyaminoalkyl methacrylates such as polyallylamine, and polydimethylaminoethyl methacrylate.

  The number average molecular weight of the basic nitrogen-containing group raw material is preferably 100 or more, more preferably 500 or more, and still more preferably 1,000 or more, from the viewpoint of adsorptivity to the resin having an acidic group, and the dispersion of toner particles From the viewpoint of property, it is preferably 15,000 or less, more preferably 10,000 or less, and still more preferably 5,000 or less.

  Examples of the dispersible group raw material include halogenated hydrocarbons having 16 or more carbon atoms, hydrocarbons having 16 or more carbon atoms having a reactive functional group, polymers of hydroxycarboxylic acids having 16 or more carbon atoms, and 2 or more carbon atoms. A polymer of a dibasic acid having 22 or less and a diol having 2 to 22 carbon atoms, a polymer of an alkyl (meth) acrylate having 16 or more carbon atoms having a reactive functional group, a polyolefin having a reactive functional group, etc. Can be mentioned. Among these, from the viewpoint of availability of raw materials and reactivity, halogenated hydrocarbons having 16 or more carbon atoms, hydrocarbons having 16 or more carbon atoms having reactive functional groups, and reactive functional groups. A polymer of an alkyl (meth) acrylate having 16 to 24 carbon atoms or a polyolefin having a reactive functional group is preferred. Examples of the reactive functional group include a carboxy group, an epoxy group, a formyl group, and an isocyanate group. Among these, a carboxy group or an epoxy group is preferable from the viewpoint of safety and reactivity. Accordingly, a carboxylic acid compound is preferable as the compound having a reactive functional group. Examples of carboxylic acid compounds include fumaric acid, maleic acid, ethanoic acid, propanoic acid, butanoic acid, succinic acid, oxalic acid, malonic acid, tartaric acid, their anhydrides, or alkyl esters having 1 to 3 carbon atoms. Etc. Specific examples of the dispersible group raw material include halogenated alkanes such as chlorooctadecane, epoxy-modified polyoctadecyl methacrylate, polyethylene succinic anhydride, chlorinated polypropylene, polypropylene succinic anhydride, polyisobutene succinic anhydride, and the like.

  The content of the compound having a polyolefin skeleton in the dispersible group raw material is preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and further preferably from the viewpoint of dispersibility of the toner particles. 100% by mass.

  The number average molecular weight of the dispersible group raw material is preferably 500 or more, more preferably 700 or more, and further preferably 900 or more, from the viewpoint of dispersibility of the toner particles, and the adsorptivity of the dispersant to the toner particles. From the viewpoint, it is preferably 5,000 or less, more preferably 4,000 or less, and still more preferably 3,000 or less.

  The mass ratio of the basic nitrogen-containing group to the dispersible group in the basic dispersant (basic nitrogen-containing group / dispersible group) is preferably 3/97 or more from the viewpoint of adsorptivity to the toner particles. The ratio is preferably 5/95 or more, and preferably 20/80 or less, more preferably 15/85 or less from the viewpoint of dispersion stability of the toner particles. The mass ratio of the basic nitrogen-containing group and the dispersible group in the basic dispersant can be measured by NMR of the basic dispersant, but the basic dispersion in which the basic nitrogen-containing group raw material and the dispersible group raw material are reacted with each other. In the production of the agent, the mass ratio of the reacted raw material compound can be regarded as the mass ratio of the basic nitrogen-containing group to the dispersible group in the dispersant (basic nitrogen-containing group / dispersible group).

  Further, the number average molecular weight of the basic dispersant is preferably 2,000 or more, more preferably 2,500 or more, more preferably 3,000 or more, further preferably 3,500 or more, from the viewpoint of low viscosity and low-temperature fixability, and From the same viewpoint, it is preferably 10,000 or less, more preferably 9,000 or less, and still more preferably 8,000 or less.

  The content of the basic dispersant is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 2 parts by mass or more, from the viewpoint of dispersion stability of the toner particles with respect to 100 parts by mass of the toner particles. From the viewpoint of chargeability of the toner, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and still more preferably 5 parts by mass or less.

  The liquid developer of the present invention may contain a known dispersant other than the basic dispersant, but the content of the basic dispersant is preferably 50% by mass or more in the dispersant. More preferably, it is 70 mass% or more, More preferably, it is 90 mass% or more, More preferably, it is 95 mass% or more, More preferably, it is 100 mass%.

The insulating liquid in the present invention means a liquid in which electricity does not easily flow, but in the present invention, the conductivity of the insulating liquid is preferably 1.0 × 10 ⁻¹¹ S / m or less, more preferably 5.0. × 10 ⁻¹² S / m or less, and preferably 1.0 × 10 ⁻¹³ S / m or more.

The insulating liquid in the present invention contains polybutene and olefin in a predetermined ratio, thereby significantly improving film deformation suppression and drying resistance.
The reason for such an effect is not necessarily clear, but is considered as follows. Polybutene has a bulky molecular structure, so its intermolecular force is weaker than normal paraffins and olefins of the same molecular weight, and it quickly evaporates at the time of fixing. is there. On the other hand, since olefin has a double bond, its polarity is higher than that of saturated hydrocarbon, and its affinity with resin is high. Therefore, by containing a specific amount of olefin, when heated to a high temperature during fixing, the resin can be easily plasticized or swelled to improve the low-temperature fixability, but the intermolecular force is strong and hardly volatilizes during fixing. It tends to remain. However, in the present invention, by setting the average value of the double bond position of the olefin to 2 or more and the number of carbons to 16, it can be adjusted to an appropriate intermolecular force and volatilized at the time of fixing while maintaining the drying property at room temperature. It is presumed that low temperature fixability, film deformation suppression, and drying suppression can be satisfied.

  In the present invention, polybutene is obtained by polymerizing butene or isobutene by a known method, for example, cationic polymerization using a catalyst, and then hydrogenating the terminal double bond.

  Examples of the catalyst used in the cationic polymerization method include aluminum chloride, acidic ion exchange resin, sulfuric acid, boron fluoride and complexes thereof. The polymerization reaction can also be controlled by adding a base to the catalyst.

  The degree of polymerization of polybutene is preferably 8 or less, more preferably 6 or less, still more preferably 5 or less, and even more preferably 4 or less, from the viewpoint of improving the low-temperature fixability of the toner. Further, from the viewpoint of suppressing charger contamination, it is preferably 2 or more, more preferably 3 or more.

  Since the product obtained by the polymerization reaction has a double bond at the polymerization terminal, a hydrogenated product is obtained by a hydrogenation reaction. The hydrogenation reaction can be performed, for example, using nickel or palladium as a hydrogenation catalyst at a temperature of 180 to 230 ° C., and contacting hydrogen at a pressure of 2 to 10 MPa.

  Examples of the commercially available insulating liquid containing polybutene include “NAS-3”, “NAS-4”, “NAS-5H” (all of which are manufactured by NOF Corporation). One or more of these can be combined.

  An olefin is an olefin having 16 carbon atoms, and an internal olefin having an average double bond position (DBP average value) calculated from the mass ratio of the double bond distribution of 2 or more (hereinafter, simply referred to as “internal olefin”). Say).

The olefin is a hydrocarbon compound having one or more carbon-carbon double bonds in the molecule. For example, the 1-hexadecene DBP average value is 1, the 2-hexadecene DBP average value is 2, and the DBP average The larger the value, the higher the proportion of double bonds existing inside the carbon chain. The DBP average value of the internal olefin in the present invention is preferably 3 or more, more preferably 4 or more, and preferably 6 or less, more preferably 5 or less. In the case of an olefin having 16 carbon atoms, the maximum value of DBP and its average value is 8.
When it is a mixture of multiple types of hexadecene as in the composite, the double bond distribution is
C1 position: a mass%, C2 position: b mass%, C3 position: c mass%, C4 position: d mass%, C5 position: e mass%, C6 position: f mass%, C7 position: g mass%, C8 Rank: h mass% (total 100 mass%)
Then, the DBP average value is
(1 × a + 2 × b + 3 × c + 4 × d + 5 × e + 6 × f + 7 × g + 8 × h) / 100
Is calculated from In addition, the position of the double bond in an olefin can be confirmed with a gas chromatograph mass spectrometer (GC-MS), for example. Specifically, the ratio of each olefin can be determined from the GC peak area by accurately separating components having different carbon chain lengths and double bond positions by a gas chromatograph analyzer (GC). Furthermore, the double bond position in an olefin can be identified by a mass spectrometer (MS).
Even if the number of carbon atoms is 16, if the DBP average value is less than 2, there is a problem in both drying of the liquid developer and deformation of the resin film. Although it is effective in preventing the agent from drying, it is difficult to volatilize, and therefore, it has high persistence in printed matter, and even if the DBP average value is 2 or more, deformation of the resin film cannot be suppressed.

  From the viewpoint of improving the storage stability of the liquid developer, the number of double bonds in one olefin molecule is preferably 3 or less, more preferably 2 or less, and even more preferably 1.

  The molecular chain of the internal olefin may be linear or branched, but preferably has a branched structure from the viewpoint of reducing the viscosity of the liquid developer.

  The internal olefin is obtained by dehydration of 1-hexadecanol in the presence of an acid catalyst, but in order to increase the DBP average value, it is required to control the purity of the raw material and the reaction conditions (temperature, time). .

  The mass ratio of polybutene to the olefin (polybutene / olefin) is 60/40 or more, preferably 65/35 or more, more preferably 70/30 or more, from the viewpoints of low-temperature fixability and resin film deformation suppression. From the viewpoint of reducing volatilization, it is 90/10 or less, preferably 85/15 or less, more preferably 80/20 or less.

  Specific examples of the insulating liquid other than polybutene and the olefin include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, polysiloxanes, vegetable oils and the like other than these.

  The total content of polybutene and the olefin in the insulating liquid is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.

  The viscosity at 25 ° C. of the insulating liquid is preferably 1 mPa · s or more, and preferably 100 mPa · s, from the viewpoint of improving developability and improving the storage stability of the toner particles in the liquid developer. · S or less, more preferably 50 mPa · s or less, further preferably 20 mPa · s or less, further preferably 10 mPa · s or less, and further preferably 5 mPa · s or less. The viscosity of the insulating liquid is a weighted average value of the respective viscosity constituting the insulating liquid.

  The liquid developer is obtained by dispersing toner particles in an insulating liquid. From the viewpoint of reducing the particle size of the toner particles, it is preferable to disperse the toner particles in an insulating liquid and then wet pulverize to obtain a liquid developer.

  As a method of mixing the toner particles, the dispersant, and the insulating liquid, a method of stirring with a stirring and mixing device is preferable.

  The stirring and mixing device is not particularly limited, but from the viewpoint of improving the productivity and storage stability of the toner particle dispersion, a high-speed stirring and mixing device is preferable. Specifically, Despa (manufactured by Asada Tekko Co., Ltd.), TK homomixer, TK homodisper, TK robotics (all of which are manufactured by Primics Co., Ltd.), Claremix (manufactured by M Technique Co., Ltd.), KD Mill (manufactured by KD International) Etc.) are preferred.

  By mixing with a high-speed stirring and mixing device, toner particles are preliminarily dispersed to obtain a toner particle dispersion, and the productivity of the liquid developer by the subsequent wet pulverization is improved.

  From the viewpoint of improving the image density, the solid content concentration of the toner particle dispersion is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 33% by mass or more. From the viewpoint of improving the property and improving the storage stability, it is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

  The wet pulverization is a method in which toner particles dispersed in an insulating liquid are mechanically pulverized in a state of being dispersed in the insulating liquid.

  As a device to be used, for example, a generally used stirring and mixing device such as an anchor blade can be used. Among the stirring and mixing devices, high speed stirring and mixing devices such as Despa (manufactured by Asada Tekko Co., Ltd.), TK. Etc. A plurality of these devices can be combined.

  Among these, the use of a bead mill is used from the viewpoint of reducing the particle size of the toner particles, improving the storage stability of the toner particles by improving the dispersion stability of the toner particles, and reducing the viscosity of the dispersion. preferable.

  In the bead mill, toner particles having a desired particle size and particle size distribution can be obtained by controlling the particle size and filling rate of the medium used, the peripheral speed of the rotor, the residence time, and the like.

  From the viewpoint of improving the image density, the solid concentration of the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more, and the dispersion stability of the toner particles. From the viewpoint of improving the storage stability by improving the content, it is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

  The content of the toner particles in the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more from the viewpoint of high-speed printing, and the dispersion stability of the toner particles From the viewpoint of safety, it is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

From the viewpoint of reducing the viscosity of the liquid developer, the volume median particle size (D ₅₀ ) of the toner particles in the liquid developer is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more. From the viewpoint of improving the image quality of the liquid developer, it is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 2.5 μm or less.

  The content of the insulating liquid in the liquid developer is preferably 50% by mass or more, more preferably 55% by mass or more, further preferably 60% by mass or more, from the viewpoint of dispersion stability of the toner particles, and From the viewpoint of high-speed printing, it is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less.

  The viscosity at 25 ° C. of the liquid developer having a solid content concentration of 25% by mass is preferably 3 mPa · s or more, more preferably 5 mPa · s, from the viewpoint of improving the storage stability by improving the dispersion stability of the toner particles. Or more, more preferably 6 mPa · s or more, more preferably 7 mPa · s or more, and from the viewpoint of improving the fixability of the liquid developer, preferably 50 mPa · s or less, more preferably 40 mPa · s or less, Preferably it is 37 mPa · s or less, more preferably 35 mPa · s or less, more preferably 32 mPa · s or less, more preferably 28 mPa · s or less, more preferably 24 mPa · s or less, more preferably 20 mPa · s or less, more preferably 16 mPa · s or less.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical properties of the resin and the like were measured by the following method.

[Softening point of resin]
Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, and a 1.96 MPa load was applied by a plunger, and the diameter was 1 mm and the length was 1 mm. Extrude from the nozzle. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Maximum peak temperature of resin endotherm]
Using a differential scanning calorimeter “Q-100” (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, and the temperature drop rate is 10 ° C. from room temperature (25 ° C.). Cool to 0 ° C at / min and maintain at 0 ° C for 1 minute. Thereafter, the measurement is performed at a heating rate of 10 ° C./min. Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the highest endothermic peak temperature.

[Glass transition temperature of resin]
Using a differential scanning calorimeter “DSC210” (manufactured by Seiko Denshi Kogyo Co., Ltd.), 0.01 to 0.02 g of sample was weighed into an aluminum pan, heated to 200 ° C., and the temperature was reduced to 0 ° C./min. Cool to ° C. Next, the sample is heated at a heating rate of 10 ° C./min, and the endothermic peak is measured. The glass transition temperature is defined as the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Acid value of the resin]
Measured by the method of JIS K0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Volume-median particle size of toner particles before mixing with insulating liquid]
Measuring machine: Coulter Multisizer II (manufactured by Beckman Coulter, Inc.)
Aperture diameter: 100μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter, Inc.)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (Griffin): 13.6) dissolved in the electrolyte to adjust to 5% by mass Dispersion condition: 10 mL of measurement sample in 5 mL of the dispersion And is dispersed for 1 minute with an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80 W). Thereafter, 25 mL of the electrolytic solution is added and further dispersed for 1 minute with an ultrasonic disperser to prepare a sample dispersion.
Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte so that the particle size of 30,000 particles could be measured in 20 seconds, and 30,000 particles were measured. Determine the median particle size (D ₅₀ ).

[Number average molecular weight of basic nitrogen-containing base material]
The molecular weight distribution is measured by the gel permeation chromatography (GPC) method shown below to determine the number average molecular weight.
(1) so that the preparation concentration of the sample solution becomes 0.2 g / 100 mL, dissolved in a solution sample was over Na ₂ SO ₄ was dissolved in 1% aqueous acetic acid in 0.15 mol / L. Next, this solution is filtered using a fluororesin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 0.2 μm to remove insoluble components to obtain a sample solution.
(2) using the analytical column the molecular weight measurement following measurement apparatus, a solution prepared by dissolving over Na ₂ SO ₄ in 1% acetic acid aqueous solution at 0.15 mol / L as the eluent, at a flow rate per minute 1 mL, of 40 ° C. Stabilize the column in a constant temperature bath. Inject 100 μL of the sample solution into the sample and perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. There are several standard pullulans (P-5 (Mw 5.9 × 10 ³ ), P-50 (Mw 4.73 × 10 ⁴ ), P-200 (Mw 2.12 × 10) manufactured by Showa Denko KK). ⁵ ) Use P-800 (Mw 7.08 × 10 ⁵ )) as a standard sample. The molecular weight is shown in parentheses.
Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation)
Analysis column: α + α-M + α-M (manufactured by Tosoh Corporation)

[Number average molecular weight of dispersible group raw material]
(1) The dispersible group raw material was dissolved in tetrahydrofuran so that the preparation concentration of the sample solution was 0.5 g / 100 mL. Subsequently, this solution was filtered using a fluororesin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 2 μm to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Using the following measuring device and analytical column, tetrahydrofuran is flowed as an eluent at a flow rate of 1 mL per minute, and the column is stabilized in a constant temperature bath at 40 ° C. Inject 100 μL of the sample solution into the sample and perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curves at this time include several types of monodisperse polystyrene (A-500 (Mw 5.0 × 10 ² ), A-1000 (Mw 1.01 × 10 ³ ), A-2500 (Mw 2.63 × 10) manufactured by Tosoh Corporation. ³ ), A-5000 (Mw 5.97 × 10 ³ ), F-1 (Mw 1.02 × 10 ⁴ ), F-2 (Mw 1.81 × 10 ⁴ ), F-4 (Mw 3.97 × 10 ⁴ ), F-10 (Mw 9.64 × 10 ⁴ ), F-20 (Mw 1.90 × 10 ⁵ ), F-40 (Mw 4.27 × 10 ⁵ ), F-80 (Mw 7.06 × 10 ⁵ ), F-128 (Mw 1.09 × 10 ⁶ )) Is used as a standard sample. The molecular weight is shown in parentheses.
Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)
Analytical column: GMHXL + G3000HXL (manufactured by Tosoh Corporation)

[Number average molecular weight of dispersant]
The molecular weight distribution is measured by the gel permeation chromatography (GPC) method shown below to determine the number average molecular weight.
(1) Preparation of sample solution Dissolve the dispersant in chloroform so that the concentration is 0.2 g / 100 mL. Next, this solution is filtered using a fluororesin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 0.2 μm to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Using the following measuring device and analytical column, a chloroform solution of 1.00 mmol / L Pharmin DM2098 (manufactured by Kao Corporation) was flowed as an eluent at a flow rate of 1 mL / min. Stabilize the column in. Inject 100 μL of the sample solution into the sample and perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curves at this time include several types of monodisperse polystyrene (A-500 (Mw 5.0 × 10 ² ), A-5000 (Mw 5.97 × 10 ³ ), F-2 (Mw 1.81 × 10) manufactured by Tosoh Corporation. ⁴ ), F-10 (Mw 9.64 × 10 ⁴ ), F-40 (Mw 4.27 × 10 ⁵ )) are used as standard samples. The molecular weight is shown in parentheses.
Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)
Analytical column: K-804L (manufactured by Showa Denko KK)

[Measurement method of double bond distribution of internal olefin]
After reacting the internal olefin with dimethyl disulfide to obtain a dithiolated derivative, components having different carbon chain lengths and double bond positions are separated by gas chromatography (GC). The proportion of internal olefins having different double bond positions is determined from the respective peak areas. Double bond positions are identified by mass spectrometer (MS).
The apparatus and analysis conditions used for GC-MS measurement are as follows.
GC device: 6890 (manufactured by Agilent Technologies)
Column: BPX-35 25m x 0.22mm x 0.25μm (SGE)
Carrier gas: He (column flow rate 1.0mL / min)
Injection mode: Split (100: 1)
Injector temperature: 300 ℃
Column oven temperature: Heated from 60 ° C at 2 ° C / min and held at 300 ° C for 5 min MS device: 5975 (manufactured by Agilent Technologies)
Ion source temperature: 230 ° C
Analyzer temperature: 150 ° C (quadrupole)
Transfer line temperature: 300 ° C
Ionization mode: EI
Scan range: m / z 25-500

[Conductivity of insulating liquid]
Put 25 g of insulating liquid into a 40 mL glass sample tube “Screw No. 7” (manufactured by Marumu Co., Ltd.), and use a non-aqueous conductivity meter “DT-700” (manufactured by Dispersion Technology) to connect the electrode. Immerse in an insulating liquid, measure 20 times at 25 ° C, calculate the average value, and measure the conductivity. The smaller the value, the higher the resistance.

[Viscosity of insulating liquid and liquid developer at 25 ° C]
Put 6 to 7 mL of the measured solution in a 10 mL screw tube, and use the rotational vibration viscometer “Viscomate VM-10A-L” (manufactured by Seconic, detection terminal: titanium, φ8 mm), and the tip of the detection terminal Fix the screw tube at the position where the liquid level is 15mm above the part, and measure the viscosity at 25 ° C.

[Solid content concentration of toner particle dispersion and liquid developer]
10 parts by mass of the sample is diluted with 90 parts by mass of hexane, and is rotated for 20 minutes at a rotational speed of 25,000 r / min using a centrifugal separator “H-201F” (manufactured by Kokusan Co., Ltd.). After standing, the supernatant is removed by decantation, diluted with 90 parts by mass of hexane, and centrifuged again under the same conditions. After removing the supernatant by decantation, the lower layer is dried in a vacuum dryer at 0.5 kPa and 40 ° C. for 8 hours, and the solid content concentration is calculated from the following formula.

[Volume Median Particle Size (D ₅₀ ) of Toner Particles in Liquid Developer]
Using a laser diffraction / scattering particle size measuring device “Mastersizer 2000” (Malvern), add Isopar L (ExxonMobil, isoparaffin, viscosity 1 mPa · s at 25 ° C.) to the measurement cell, and then the scattering intensity. The volume median particle size (D ₅₀ ) is measured under the conditions of a particle refractive index of 1.58 (imaginary part 0.1) and a dispersion medium refractive index of 1.42 at a concentration of 5 to 15%.

Resin production example 1
The raw material monomer and esterification catalyst shown in Table 1 were put into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 230 ° C. using a mantle heater. The reaction is carried out at 230 ° C. until the reaction rate reaches 90%, and further the reaction is carried out at 8.3 kPa until the softening point shown in Table 1 is reached, to obtain a polyester resin (resin A) having the physical properties shown in Table 1. It was. In the resin production example, the reaction rate means a value of the amount of generated reaction water (mol) / theoretical generated water amount (mol) × 100.

Resin production example 2
The raw material monomer and the esterification catalyst shown in Table 1 were put into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 180 ° C. using a mantle heater. The temperature was raised to 220 ° C. over 10 hours, the reaction was carried out at 220 ° C. until the reaction rate reached 90%, and the reaction was further carried out at 8.3 kPa until the softening point shown in Table 1 was reached. A polyester resin (resin B) having the physical properties shown in FIG.

Dispersant Production Example 1
20 parts by mass of polyethyleneimine (polyethyleneimine 600, manufactured by Junsei Chemical Co., Ltd., branched structure, Mn: 2500) as a basic nitrogen-containing raw material was equipped with a condenser, nitrogen inlet, stirrer, dehydrator and thermocouple. The reaction vessel was replaced with nitrogen gas in a 2 L four-necked flask. A solution obtained by dissolving 197 parts by mass of polyisobutene succinic anhydride (PIBSA) (OLOA15500, manufactured by Chevron Japan Co., Ltd., effective content: 78% by mass, Mn: 1100) as a dispersible base material in 217 parts by mass of xylene while stirring. Was added dropwise at room temperature over 1 hour. After completion of dropping, the mixture was kept at room temperature for 30 minutes. Thereafter, the inside of the reaction vessel was heated to 150 ° C. and held for 1 hour, and then heated to 160 ° C. and held for 1 hour. Depressurize to 8.3 kPa at 160 ° C and distill off the solvent. From the IR analysis, the PIBSA-derived acid anhydride peak (1780 cm ^-1 ) disappeared and the imide bond-derived peak (1700 cm ^-1 ) occurred. As a reaction end point, dispersant A (Mn: 6700, basic nitrogen-containing group raw material / dispersible group (mass ratio): 11/89) was obtained.

Production example 1 of internal olefin
In a flask equipped with a stirrer, 1-hexadecanol “Calcol 6098” (Kao Co., Ltd.) 7000 g (28.9 mol) and γ-alumina (STREM Chemicals, Inc.) 1050 g as a solid acid catalyst (raw alcohol 100 parts by mass) The reaction was carried out for 13 hours while flowing nitrogen (7000 mL / min) through the system at 275 ° C. with stirring. After the reaction, the alcohol conversion was 100% and the olefin purity was 99.5%. The obtained crude olefin was transferred to a distillation flask and distilled at 148 to 158 ° C./0.5 mmHg to obtain a C16 internal olefin (C16-IO) having an olefin purity of 100%.
The double bond distribution of the resulting internal olefin is
C1 position: 1.5 mass%, C2 position: 20.4 mass%, C3 position: 17.7 mass%, C4 position: 18.2 mass%, C5 position: 15.0 mass%, C6 position: 12.4 mass%, C7 position: 7.4 mass%, C8 Rank: 7.4% by mass
The DBP average value was 4.3.

Production example 2 of internal olefin
In a flask equipped with a stirrer, 1-octadecanol “Calcoal 8098” (Kao Co., Ltd.) 7000 g (25.9 mol), γ-alumina (STREM Chemicals, Inc.) 1050 g as a solid acid catalyst (100 parts by mass of raw alcohol) The reaction was carried out for 13 hours while stirring and flowing nitrogen (7000 mL / min) through the system at 285 ° C. with stirring. After the reaction, the alcohol conversion was 100% and the olefin purity was 98.5%. The obtained crude olefin was transferred to a distillation flask and distilled at 148 to 158 ° C./0.5 mmHg to obtain an internal olefin having 18% carbon purity (C18-IO) having an olefin purity of 100%.
The double bond distribution of the resulting internal olefin C18-IO is
C1 position: 0.3 mass%, C2 position: 13.3 mass%, C3 position: 12.6 mass%, C4 position: 13.9 mass%, C5 position: 14.8 mass%, C6 position: 13.7 mass%, C7 position: 12.6 mass%, C8 Rank: is 9.4 mass%, C9: is 9.4 mass%
The DBP average value was 5.2.

  Table 2 shows insulating liquids used in Examples and Comparative Examples.

Examples 1-5 and Comparative Examples 1-5
Rotate 80 parts by mass of the binder resin shown in Table 3 and 20 parts by mass of the colorant “ECB-301” (manufactured by Dainichi Seika Kogyo Co., Ltd., phthalocyanine blue 15: 3) using a 20 L Henschel mixer in advance. After stirring and mixing for several minutes at several 1500 r / min (circumferential speed 21.6 m / sec), the mixture was melt-kneaded under the following conditions.

[Melting and kneading conditions]
A continuous two-open roll kneader “NIDEX” (manufactured by Nippon Coke Industries Co., Ltd., roll outer diameter: 14 cm, effective roll length: 55 cm) was used. The operating conditions of the continuous two-open roll type kneader are: high rotation side roll (front roll) rotation speed 75r / min (circumferential speed 32.4m / min), low rotation side roll (back roll) rotation speed 35r / min ( The peripheral speed was 15.0 m / min), and the roll clearance at the end of the kneaded product supply port was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll are 90 ° C. on the raw material input side of the high rotation side roll and 85 ° C. on the kneaded material discharge side, 35 ° C. on the raw material input side of the low rotation side roll and 35 ° C. on the kneaded material discharge side. there were. The feed rate of the raw material mixture to the kneader was 10 kg / h, and the average residence time in the kneader was about 3 minutes.

The obtained kneaded product was rolled and cooled with a cooling roll, and then roughly pulverized to about 1 mm using a hammer mill. The obtained coarsely pulverized product was finely pulverized and classified by an airflow jet mill “IDS” (manufactured by Nippon Pneumatic Co., Ltd.) to obtain toner particles having a volume median particle size (D ₅₀ ) of 10 μm.

  A mixture of 35 parts by mass of the obtained toner particles and insulating liquid A and insulating liquid B in the mass ratio shown in Table 3 (Comparative Example 1 is only insulating liquid A) 183 parts by mass) and 1.05 parts by mass of Dispersant A (3 parts by mass with respect to 100 parts by mass of toner particles) are placed in a 1 L polyethylene container, and “TK Robotics” (manufactured by Primics Co., Ltd.) Under ice cooling, the mixture was stirred for 30 minutes at a rotation speed of 7000 r / min to obtain a toner particle dispersion having a solid content concentration of 36% by mass.

Next, the obtained toner particle dispersion was rotated with a 6-cylinder sand mill “TSG-6” (manufactured by IMEX Co., Ltd.) using zirconia beads having a diameter of 0.8 mm at a volume filling rate of 60% by volume. Wet grinding was performed at 1300 r / min (circumferential speed 4.8 m / sec) until the volume-median particle size (D ₅₀ ) shown in Table 3 was obtained. After removing the beads by filtration, 44 parts by mass of the same insulating liquid used for preparing the toner particle dispersion (126 parts by mass with respect to 100 parts by mass of toner particles) is added to 100 parts by mass of the filtrate. The liquid developer having the physical properties shown in Table 3 having a solid content concentration of 25% by mass was obtained.

Test Example 1 [low temperature fixability]
A liquid developer was dropped onto the printing paper “POD gloss coated paper” (manufactured by Oji Paper Co., Ltd.), and a thin film was prepared with a wire bar so that the mass after drying was 1.2 g / m ² . Then, it hold | maintained for 10 second in an 80 degreeC thermostat.

  Subsequently, using a fixing device taken out from “OKI MICROLINE 3010” (manufactured by Oki Data Co., Ltd.), fixing processing was performed at a fixing roll temperature of 80 ° C. and a fixing speed of 280 mm / sec. Thereafter, the fixing roll temperature was increased to 120 ° C. by 10 ° C., and the fixing process was performed in the same manner to obtain a fixed image at each temperature.

  Affix the mending tape “Scotch Mending Tape 810” (manufactured by 3M Japan Co., Ltd., width 18mm) to the fixed image obtained, apply pressure to the tape with a roller so that a load of 500g is applied, and then apply the tape. It peeled. The image density before tape application and after peeling was measured using a color meter “GretagMacbeth Spectroeye” (manufactured by Gretag). The image printed portion was measured at three points, and the average value was calculated as the image density. The fixing rate (%) was calculated from the value of image density after peeling / image density before sticking × 100, and the temperature at which the fixing rate reached 90% or more was defined as the minimum fixing temperature. The results are shown in Table 3.

Test Example 2 [Drying resistance]
Drop the liquid developer onto the resin film “PET Film Lumirror T60 # 75” (manufactured by Toray Industries, Inc.), and use a wire bar to form a thin film so that the liquid developer has a mass of 13 g / m ² when dropped. Produced. Thereafter, the state after standing for 1 day in an environment of a temperature of 25 ° C. and a relative humidity of 50% was observed, and drying resistance was evaluated according to the following evaluation criteria. The results are shown in Table 3.

〔Evaluation criteria〕
A: No drying at all B: Partially dried, but no problem in practical use C: Dry but redispersed by addition of insulating liquid D: Dry, insulating liquid Redispersion difficult even with addition of E: Completely coated

Test Example 3 [Inhibition of film deformation]
In the fixing test of Test Example 1, the printed matter on which the image was fixed at 120 ° C. was wrapped with a polypropylene film “biaxially stretched PP film FOR # 25” (Futamura Chemical Co., Ltd.), and the temperature was 25 ° C. and the relative humidity was 50%. I left it in the environment for a day. The state of the film after standing was observed, and the presence or absence of film deformation was evaluated according to the following evaluation criteria. The results are shown in Table 3.

〔Evaluation criteria〕
A: No deformation is observed at all B: Wrinkles are generated, but there is no problem in actual use C: Wrinkles are generated and there is a problem in actual use D: Large wrinkles are observed E: Large deformation is observed

From the above results, it can be seen that the liquid developers of Examples 1 to 5 are excellent in low-temperature fixability and difficult to dry, but the deformation of the resin film is suppressed.
On the other hand, the liquid developer of Comparative Example 1 containing no olefin is solidified by drying, and the liquid developer of Comparative Example 3 having too much olefin lacks low-temperature fixability and is a deformed resin film. Has occurred. In addition, the liquid developer of Comparative Example 2 containing an olefin that is not an internal olefin is easy to dry and the resin film is deformed. Even if it is an internal olefin, the liquid developer contains an olefin having 18 carbon atoms. In the liquid developers of Examples 4 and 5, deformation of the resin film cannot be suppressed.

The liquid developer of the present invention is suitably used for developing a latent image formed in, for example, electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (5)

  A liquid developer containing toner particles containing a binder resin and a colorant, a dispersant, and an insulating liquid, wherein the insulating liquid contains polybutene and olefin in a mass ratio of 60/40 to 90/10 ( Polybutene / olefin), and the olefin is an internal olefin having 16 carbon atoms and an average double bond position calculated from the mass ratio of the double bond distribution of 2 or more.   The liquid developer according to claim 1, wherein the binder resin includes a polyester resin.   The liquid developer according to claim 1, wherein the dispersant contains a basic dispersant having a basic nitrogen-containing group.   The liquid developer according to claim 3, wherein the basic nitrogen-containing group is an imino group.   The liquid developer according to claim 3 or 4, wherein the basic dispersant has a polyisobutene skeleton.