JP2016060854A - Inkjet ink, ink cartridge and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet ink, an ink cartridge and an inkjet recording method capable of recording an image having abrasion resistance required in such fields as a commercial printing field and an office printing field.SOLUTION: An inkjet ink includes a resin particle, and the resin particle contains a resin having a silsesquioxane structure. Further, an inkjet ink includes a resin particle, and the resin particle contains a compound having a silsesquioxane structure.SELECTED DRAWING: None

Description

  The present invention relates to an ink jet ink, an ink cartridge having the ink, and an ink jet recording method using the ink.

  In recent years, ink jet recording apparatuses have been increasingly used in commercial printing, office printing, and the like as the image quality of recorded images is improved and the recording speed is increased. In these fields, as an ink for an ink jet recording apparatus (ink jet ink), an ink capable of recording an image having excellent scratch resistance is required. As a measure for improving the scratch resistance of the recorded image, it is known to contain resin particles in the ink. For example, Patent Document 1 describes an ink composition in the form of an emulsion containing resin particles obtained by emulsion polymerization of an ethylenically unsaturated monomer.

  On the other hand, it is known to include an organic-inorganic composite material in the ink. For example, Patent Document 2 discloses an aqueous ink composition containing an amphiphilic polymer having a silsesquioxane unit for the purpose of improving the water resistance of a recorded image.

JP 2006-188601 A Japanese Patent Laid-Open No. 10-7958

  Since most of the resin particles described in Patent Document 1 are made of an organic material, there is a limit to the effect of improving the scratch resistance of the obtained image, and characteristics sufficient for use in the above field cannot be obtained. It was. The resin described in Patent Document 2 contains a polymer having a silsesquioxane unit, which is an organic-inorganic composite material. However, since the polymer is dissolved in ink, recording such as paper is performed. Easy to penetrate into the medium. As a result, even when the polymer was used, a satisfactory level of scratch resistance was not obtained.

  Accordingly, an object of the present invention is to provide an ink jet ink, an ink cartridge, and an ink jet recording method capable of recording an image having excellent scratch resistance.

  The above object is achieved by the present invention described below. That is, according to the present invention, there is provided an ink for ink jetting containing resin particles, wherein the resin particles contain a resin having a silsesquioxane structure. The present invention also provides an ink jet ink containing resin particles, wherein the resin particles encapsulate a compound having a silsesquioxane structure.

  According to the ink, the ink cartridge, and the ink jet recording method of the present invention, it is possible to record an image having excellent scratch resistance.

It is a perspective view of the mechanism part of an inkjet recording device. FIG. 6 is a perspective view illustrating a state where an ink cartridge is mounted on the head cartridge.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments.
The ink of the present invention contains resin particles, and the resin particles contain a resin having a silsesquioxane structure.

First, the effect of the silsesquioxane structure will be described. In the present invention, the “silsesquioxane structure” is a structure represented by the composition formula of RSiO _1.5 , one of the four bonds of the silicon atom is bonded to the organic group R, and the other three are siloxanes. A generic term for polysiloxane structures forming bonds (Si—O—Si). Here, R is an arbitrary substituent composed of an organic group. That is, the silsesquioxane structure is an organic-inorganic composite structure composed of an organic portion composed of the organic group R and an inorganic portion composed of a siloxane bond. The silsesquioxane structure has a siloxane bond having a bond energy higher than that of a carbon-carbon bond, and is a network structure in which adjacent silicon atoms are bonded by three siloxane bonds branched from a silicon atom. . Therefore, in the silsesquioxane structure, the inorganic portion composed of siloxane bonds has high strength and is stable against external force.

  The silsesquioxane structure can usually impart inorganic material characteristics to resin particles formed of an organic material. When the ink containing the resin particles is used, deterioration of the image due to rubbing can be suppressed by the robust silsesquioxane structure existing in the resin film formed near the surface of the image.

  In the present invention, the resin particles may include a compound having a silsesquioxane structure. “The resin particles contain a compound having a silsesquioxane structure” means that the resin particles are not chemically bonded to the resin constituting the resin particles (in a free state, they are physically mixed). It means having a silsesquioxane structure. However, in the present invention, the resin particles preferably include a resin having a silsesquioxane structure. For example, the resin constituting the resin particles is preferably covalently bonded, ionic bond, hydrogen bond, or coordinate bond via an organic group, and more preferably covalently bonded. When the silsesquioxane structure is covalently bonded to the resin via an organic group, even if an external force is applied to the image when the image is scratched, the silsesquioxane structure is protected from the surface of the resin film by a stable covalent bond. The sesquioxane structure is prevented from falling off. Therefore, the scratch resistance of the image can be maintained for a longer period.

  A preferable embodiment of the present invention includes an embodiment in which the silsesquioxane structure is at least one selected from the group consisting of an alkyl group and a fluorinated alkyl group in the general formula (1). Since the alkyl group and the fluorinated alkyl group have low polarity and polarizability, the Coulomb force and intermolecular force are small. Therefore, when the silsesquioxane structure present on the surface of the resin film has the alkyl group or the like, the adhesive force on the surface of the resin film, that is, the coefficient of friction on the image surface can be reduced.

  In a more preferred embodiment of the present invention, the resin having a silsesquioxane structure further has at least one structure (polysiloxane structure) selected from a dialkylpolysiloxane structure and an alkylarylpolysiloxane structure. Can be mentioned. This is because the polysiloxane structure has the same effect as the alkyl group and fluorinated alkyl group in that it reduces the adhesion of the resin film surface, that is, the coefficient of friction of the image surface, and further improves the scratch resistance of the image. is there. Further, since the polysiloxane structure is thermally and chemically stable, there is an effect of improving the storage stability of the entire ink.

  Next, the effect of the resin particles will be described. In the present invention, a resin having a silsesquioxane structure is not dissolved in the ink but is contained in the resin particles. Unlike the resin that dissolves in the ink, the resin particles do not form a chain in the ink but are dispersed in the form of particles. Therefore, when the ink is recorded on the surface of the recording medium, the resin particles do not penetrate the recording medium, and form a lump on the surface of the recording medium to form a resin film. As a result, a large amount of silsesquioxane structure can be present on the surface of the resin film, so that the image scratch resistance is improved.

  A preferable embodiment of the present invention includes an embodiment in which the resin particles have a core-shell structure including a core polymer and a shell polymer. The “core polymer” is a resin constituting the core particle, and the “shell polymer” is a resin constituting the shell (resin layer). In addition, it is also preferable that the resin particles have a core-shell structure including a core polymer, a first shell polymer that forms an intermediate layer, and a second shell polymer that forms a surface layer. This is because the resin particles can be highly functionalized by making the resin particles have a core-shell structure. Specifically, since the surface layer of the resin particles is a part in contact with the aqueous medium, the ink can be obtained by giving a charge to the shell polymer (particularly the second shell polymer) or introducing a bulky hydrophilic group. The dispersion stability of can be improved. The core polymer and the first shell polymer are dominant with respect to the physical properties of the resin film (friction coefficient, glass transition point, minimum film forming temperature, glossiness). Therefore, by setting these resins to a composition different from that of the shell polymer (particularly the second shell polymer), it becomes easy to adjust the resin particles to have desired physical properties.

  As a more preferable form of the present invention, a form in which at least one of the core polymer and the shell polymer has the silsesquioxane structure can be mentioned. Among them, both the core polymer and the shell polymer have the silsesquioxane structure, the content of the silsesquioxane structure in the core polymer, and the content of the silsesquioxane structure in the shell polymer, Are preferably different. Furthermore, a form in which the silsesquioxane structure is unevenly distributed in any of the core polymer and the shell polymer is preferable. By making the silsesquioxane structure imparting hardness to the resin unevenly distributed in the core particles or a specific layer of the resin layer, the resin particles are formed from a flexible portion and a hard portion. When these resin particles form a resin film on the surface of the image, a soft part and a hard part are mixed, so that a crack is not generated as a whole, and a resin film excellent in fastness and gloss is obtained. Can do. On the other hand, if the content of the silsesquioxane structure in each of the layers constituting the core polymer and the shell polymer is made constant regardless of the layer structure of the resin particles, the entire resin particles are uniformly hardened. . For this reason, a crack is easily generated in the formed resin film, and the fastness and glossiness of the resin film may be lowered. For the same reason, when the resin particles have an intermediate layer, the core polymer, the first shell polymer, and the second shell polymer are resins having different contents of the silsesquioxane structure. Form is preferred.

  Another preferred embodiment of the present invention includes a form in which at least one selected from the core polymer, the first shell polymer, and the second shell polymer has the silsesquioxane structure. Among them, the content of the silsesquioxane structure in the second shell polymer is the content of the silsesquioxane structure in the core polymer and the content of the silsesquioxane structure in the first shell polymer. A smaller one is preferred. Furthermore, it is preferable that the second shell polymer does not have the silsesquioxane structure. This is because the surface layer of the resin particles is a portion that comes into contact with the aqueous medium of the ink, and the siloxane bond in the silsesquioxane structure and the bond between the silicon and organic groups are easily hydrolyzed. When a siloxane bond or the like is hydrolyzed, a resin having a silsesquioxane structure becomes brittle, and the scratch resistance of an image formed is lowered. Therefore, it is preferable that most of the resin having the silsesquioxane structure is contained in the core particles and the intermediate layer, not in the surface layer, so as not to contact the aqueous medium.

As described above, the resin particles having the silsesquioxane structure and the resin having the silsesquioxane structure, which are characteristic structures of the present invention, have a synergistic effect. By matching, the effects of the present invention can be achieved.
Hereinafter, elements constituting the ink of the present invention will be described with specific examples.

<Ink>
The ink of the present invention is an inkjet ink containing resin particles. The ink of the present invention may contain a coloring material or an aqueous medium in addition to the resin particles. In the present invention, “ink” includes so-called clear ink which does not include a color material. Hereinafter, components that can be used in the ink of the present invention will be described. In the following description, “(meth) acrylic acid” and “(meth) acrylate” indicate “acrylic acid, methacrylic acid” and “acrylate, methacrylate”, respectively.

(Silsesquioxane structure)
In the ink of the present invention, the resin particles include a resin having a silsesquioxane structure. Silsesquioxane hydrolyzes a silane compound having an organic group R (R-SiX ₃ , X: alkoxy group, halogen atom) to form silanol R-Si (OH) ₃ , and dehydrates and condenses the silanol. , Synthesized by forming a siloxane bond. In the present specification, a material for introducing a silsesquioxane structure into a resin or resin particles constituting a resin particle, such as silsesquioxane, is referred to as a “silsesquioxane structure introduction material”. . The “silsesquioxane structure introduction material” may have a polymerizable functional group or may not have a polymerizable functional group.

Silsesquioxane structures are generally classified into a random structure, a ladder structure, and a cage structure according to the Si—O—Si skeleton. Furthermore, the cage structure is classified into T ₈ , T ₁₀ , and T ₁₂ types. In the present invention, the “silsesquioxane structure” may include any of a random structure, a ladder structure, and a cage structure, or may include only one type of these structures. A plurality of types of structures may be included. The silsesquioxane structure may be an incompletely condensed type having a hydroxy group partially on a silicon atom, or a fully condensed type having no hydroxy group on a silicon atom. Furthermore, in the silsesquioxane structure, the organic group R may be partially replaced with a hydrogen atom.

  A covalent bond between the resin constituting the resin particle and the organic group R of the silsesquioxane structure-introducing material can be formed by a chemical reaction. Examples of the chemical reaction include a polymerization reaction, a condensation reaction, or a coupling reaction. Among these, a polymerization reaction is more preferable, and a silsesquioxane structure-introducing material having a polymerizable functional group in the organic group R is copolymerized with another monomer to produce a resin having a silsesquioxane structure. be able to.

  The polymerizable functional group of the silsesquioxane structure-introducing material includes a terminal olefin type or an internal olefin type radical polymerizable functional group; a cationic polymerizable functional group such as vinyl ether or propenyl ether; anionic polymerization such as vinyl carboxy or cyanoacryloyl Functional group; Among these, a radical polymerizable functional group is preferable. The silsesquioxane structure-introducing material may contain a plurality of polymerizable functional groups.

  The organic group R other than the polymerizable functional group of the silsesquioxane structure-introducing material is not particularly limited, and may be appropriately selected according to desired physical properties. However, from the viewpoint of improving scratch resistance, it is preferably at least one organic group selected from the group consisting of alkyl groups and fluorinated alkyl groups.

Examples of the alkyl group include a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a secondary butyl group, a tertiary butyl group, a cyclohexyl group, an octyl group, a 1-adamantyl group, and a 2-adamantyl group. .
Examples of the fluorinated alkyl group include trifluoromethyl group, 3,3,3-trifluoropropyl group, perfluorobutyl group, 3,3,4,4,5,5,6,6,7,7,8, An 8,8-tridecafluorooctyl group, a perfluorooctyl group, etc. are mentioned.

  As a method for producing a resin having a silsesquioxane structure, a silane compound having a polymerizable functional group was copolymerized with another monomer, and then the silane compound unit of the copolymer was hydrolyzed to produce a resin. A method of dehydrating and condensing a silanol group is not preferable. This is because, in such a method, since silanol groups are located in the side chain of the copolymer having a low degree of freedom, dehydration condensation between the silanol groups hardly proceeds, and a resin having a silsesquioxane structure is desired. This is because it is difficult to control the physical properties. Therefore, it is preferable to prepare a silsesquioxane structure-introducing material having a polymerizable functional group in advance and then copolymerize the silsesquioxane structure-introducing material and another monomer.

As described above, the resin having a silsesquioxane structure preferably has at least one structure selected from a dialkylpolysiloxane structure and an alkylarylpolysiloxane structure. As a method of introducing these polysiloxane structures into the resin, a polysiloxane having a hydroxy group at the end is added when dehydrating and condensing silanol to form a siloxane bond in the process of producing a silsesquioxane structure-introducing material. The method of doing is mentioned. According to such a method, a part of the siloxane bond (Si—O—Si) having a silsesquioxane structure can be replaced with a polysiloxane structure (Si—O— (SiR ′ ₂ O) _n ).

  Specific examples of the polysiloxane structure include dialkylpolysiloxanes in which two R ′ are both alkyl groups such as a methyl group, an ethyl group, and an n-octyl group, and one R ′ of the two R ′ is the alkyl group. And an alkylaryl polysiloxane in which the other R ′ is an aryl group such as a phenyl group.

Examples of the silsesquioxane structure-introducing material include the following specific examples.
As a silsesquioxane structure-introducing material having a cage structure (T ₈ ), for example,
1,3,5,7,9,11,13,15-octamethylpentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13 ] octasiloxane;
1,3,5,7,9,11,13,15-octacyclohexylpentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13 ] octasiloxane;
1,3,5,7,9,11,13,15-octaphenylpentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13 ] octasiloxane;
1- (3-Cyclohexen-1-yl) -3,5,7,9,11,13,15-heptacyclopentylpentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13 ] octasiloxane;
1,3,5,7,9,11,13,15-octavinylpentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13 ] octasiloxane;
3- (3,5,7,9,11,13,15-heptaisobutylpentacyclo [9.5.1.1 ^3,9 .1 ^5,15 .1 ^7,13 ] octasiloxane-1-yl) Propyl methacrylate; and the like (all are manufactured by Sigma-Aldrich).

In addition, as a mixture of a silsesquioxane structure introduction material having a random structure, a ladder structure, and a cage structure, for example,
Silsesquioxane structure-introducing material having an acryloyl group as a polymerizable functional group (trade name: AC-SQ TA-100);
Silsesquioxane structure-introducing material having a methacryloyl group as a polymerizable functional group (trade name: MAC-SQ TM-100);
Silsesquioxane structure introduction material (trade name: MAC-SQ-F) having a perfluoroalkyl group as an organic group and an acryloyl group as a polymerizable functional group;
Silsesquioxane structure-introducing material having a silicone unit and having an acryloyl group as a polymerizable functional group (trade name: AC-SQ SI-20);
And a silsesquioxane structure-introducing material having a methacryloyl group as a polymerizable functional group (trade name: MAC-SQ SI-20); and the like (all are manufactured by Toagosei Co., Ltd.).

  In the form in which the resin particles encapsulate the compound having a silsesquioxane structure, the content (% by mass) of the silsesquioxane structure in the resin particles is not particularly limited. However, it is preferably 1% by mass or more and 50% by mass or less, more preferably 2% by mass or more and 40% by mass or less based on the total mass of the resin particles. Moreover, even if the resin particles include a resin having a silsesquioxane structure, the content (% by mass) of the silsesquioxane structure in the resin particles is not particularly limited. However, it is preferably 1% by mass or more and 40% by mass or less, more preferably 2% by mass or more and 30% by mass or less based on the total mass of the resin constituting the resin particles.

The “content of the silsesquioxane structure” is calculated using the final ink by the following method.
(1) Extracting resin particles from ink The ink is purified by density gradient centrifugation to separate the resin particles. At this time, the separation can be performed by the difference in the sedimentation coefficient of the ink-containing component in the density gradient sedimentation rate method, and by the difference in the density of the ink-containing component in the density gradient sedimentation equilibrium method.
(2) Separating resin particles into layers First, resin particles are dyed and fixed with ruthenium tetroxide, and then embedded in an epoxy resin. Next, the obtained resin particle-containing epoxy resin is cut with an ultramicrotome and then observed using a scanning transmission electron microscope (STEM). The layer structure can be confirmed from the cross-section of the resin particles, and the silicon can be quantitatively analyzed by energy dispersive X-ray spectroscopy (EDX). Thus, after measuring a silicon atom, resin which comprises each layer is isolate | separated.
The resin particles as a sample may be in a water-dispersed state or a dried film state, and are completely dissolved using a soluble organic solvent. The obtained solution is separated and fractionated for each resin constituting each layer by gel permeation chromatography (GPC).
(3) Measure “content of silsesquioxane structure” in each layer The resin constituting each layer separated by GPC is pretreated by acid decomposition (hydrofluoric acid addition) method or alkali melting method to induce Quantitative analysis of silicon is performed by coupled plasma emission spectroscopy. Comparison with the quantitative silicon analysis by STEM-EDX shows which layer the separated and purified resin constituted.
Next, the separated and purified resin is analyzed for ¹ H, ¹³ C, and ²⁹ Si by nuclear magnetic resonance (NMR) spectroscopy. In particular, it is possible to distinguish from silicon derived from the silsesquioxane structure RSiO _1.5 and silicon derived from other chemical structures from the spectrum of ²⁹ Si-NMR. That is, since the silicon content in the resin is known, the content of the partial SiO _1.5 excluding the organic group R is known from the silsesquioxane structure.
The structure of the organic group R possessed by silsesquioxane can be determined by analyzing ¹ H, ¹³ C-NMR spectra and fragment ions by matrix-assisted laser desorption / ionization mass spectrometry. In addition, the silsesquioxane structure is decomposed by treating the resin with an acid, alkali, or fluoride ion, and the organic group R is converted into a resin such as R—H, R—OH, or R—Si (OH) _3. Can be separated from the main chain. Such low molecular weight is preferable because the structure can be determined more easily.

(Resin particles)
“Resin particles” means a resin that exists in a state having a particle size. The resin particles are preferably in a state of being dispersed in the ink, that is, in the form of a so-called resin emulsion.

The volume average particle diameter (D ₅₀ ) of the resin particles is preferably 25 nm or more and 600 nm or less, more preferably 50 nm or more and 400 nm or less, and particularly preferably 60 nm or more and 300 nm or less. The ink of the present invention, as D ₅₀ is less than the resin particles 300nm or 60 nm, even when the particle size contains a relatively small resin particles, that can improve the scratch resistance of the image to be recorded Is preferable.

The volume average particle size of the resin particles is measured using an aqueous solution containing resin particles diluted with pure water as a measurement sample, and a dynamic light scattering type particle size / particle size distribution measuring device (trade name “Nanotrack UPA-EX150”). ", Nikkiso Co., Ltd.)" means a value measured under the following measurement conditions.
[Measurement condition]
SetZero: 30s
Number of measurements: 3 Measurement time: 180 seconds Shape: True sphere Refractive index: 1.59

The surface charge amount of the resin particles is preferably 0.5 [mu] mol / m ² or more 100 [mu] mol / m ² or less, and more preferably 1 [mu] mol / m ² or more 30 [mu] mol / m ² or less. The surface charge amount of the resin particles can be calculated by the following method. First, hydrochloric acid is added to the resin particles to adjust the pH of the mixture to 2, and the mixture is stirred for 24 hours. Thereafter, the mixture is centrifuged, and the precipitated solid is recovered and pulverized. To 1 g of the pulverized solid, 30 g of a 0.1 mol / L sodium hydrogen carbonate aqueous solution is added, and the mixture is stirred for 15 hours. After stirring, the mixture is centrifuged to remove coarse particles, pure water is added to 1 g of the obtained resin particle-containing supernatant, and the whole is diluted to 15 g. The obtained diluted solution is titrated with 0.1 mol / L hydrochloric acid using an automatic potentiometric titrator (trade name “AT510”, manufactured by Kyoto Electronics Industry Co., Ltd.), and the charge amount of the resin particles is measured. Then, the surface charge amount is calculated by dividing the measured charge amount by the surface area calculated from the volume average particle diameter.

  As monomers used when polymerizing the resin constituting the core particles or the resin constituting the resin layer, in addition to the silsesquioxane structure-introducing material having a polymerizable functional group, a monomer having an ethylenically unsaturated bond, and A monomer having an ionic group is preferably used.

  Monomers having only one ethylenically unsaturated bond include: alkenes such as ethylene and propylene; (meth) acrylic acid; methyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, hexadecyl (meth) acrylate Alkyl (meth) acrylates such as; hydroxy group-containing monomers such as hydroxyethyl (meth) acrylate; polyethylene oxide group-containing monomers such as polyethylene glycol monomethacrylate; aromatic hydrocarbons such as styrene and allylbenzene. These can be used alone or in combination of two or more as required. Among these, it is more preferable to use alkene having 22 or less carbon atoms, (meth) acrylic acid, alkyl (meth) acrylate having 22 or less carbon atoms in the alkyl group, and styrene. Furthermore, it is particularly preferable to use an alkyl (meth) acrylate having an alkyl group having 12 or less carbon atoms, preferably 6 or less, and more preferably 4 or less.

  Monomers having two or more ethylenically unsaturated bonds (hereinafter sometimes referred to as “crosslinking monomers”) include dienes such as butadiene and isoprene; alkynes such as acetylene; 1,4-butanediol diacrylate and nonane. Diol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, EO-modified bisphenol A diacrylate, polytetramethylene glycol diacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, propoxylated ethoxylated bisphenol A Diacrylate, ethoxylated bisphenol A diacrylate, 9,9-bis (4- (2-acryloyloxyethoxy) phenyl) fluorene, tricyclo Candimethanol diacrylate, 1,10-decanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 1 , 4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol dimethacrylate, EO-modified bisphenol A dimethacrylate, polytetramethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethyl glycol dimethacrylate, ethoxylated bisphenol A dimethacrylate, tri Cyclodecane dimethanol dimethacrylate, 1,6-hexanediol di Methacrylate, 1,9-nonanediol dimethacrylate, ethoxylated polypropylene glycol dimethacrylate, difunctional alkyl (meth) acrylates such as glycerin dimethacrylate;

  Tris (2-acryloyloxyethyl) isocyanurate, trimethylolprotan triacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, ethoxylated trimethylolpropane acrylate, pentaerythritol triacrylate, propoxylated trimethylolpropane triacrylate, Propoxylated glyceryl triacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone modified tris- (2-acryloxyethyl) isocyanurate, pentaerythritol acrylate, trimethylolpropane triacrylate, EO modified trimethylolpropane trimethacrylate, trimethylolpropane Trifunctional alkyl (meth) acrylates such as trimethacrylate;

  And tetrafunctional alkyl (meth) acrylates such as ditrimethylolprotan tetraacrylate, ethoxylated pentaerythritol tetraacrylate, and pentaerythritol tetraacrylate.

  These can be used alone or in combination of two or more as required. Among these, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethyl glycol dimethacrylate 1,4-butanediol dimethacrylate and ethylene glycol dimethacrylate are particularly preferable.

  Examples of the ionic group include a carboxy group and a quaternary ammonium group. Examples of the monomer having an ionic group (hereinafter sometimes referred to as “ionic group-containing monomer”) include (meth) acrylic acid; 2- (acryloyloxy) ethyltrimethylammonium chloride. These can be used alone or in combination of two or more as required. Among these, it is preferable to use (meth) acrylic acid.

Non-reactive surfactants such as anionic surfactants, nonionic surfactants, cationic surfactants, zwitterionic surfactants, or reactive when producing core polymer or shell polymer A surfactant may be added.
“Reactive surfactant” means a compound having at least one hydrophilic site, hydrophobic site, and ethylenically unsaturated bond in the molecule. Since the reactive surfactant has an ethylenically unsaturated bond, it is introduced into the core polymer or shell polymer as a repeating unit constituting the copolymer.

  Anionic surfactants include alkali metal salts of higher alcohol sulfates, alkali metal salts of alkylbenzene sulfonic acids, alkali metal salts of succinic acid dialkyl ester sulfonic acids, alkali metal salts of alkyl diphenyl ether disulfonic acids, and polyoxyethylene alkyls. Examples thereof include a sulfate ester of ether, a sulfate ester salt of polyoxyethylene alkylphenyl ether, a phosphate ester salt of polyoxyethylene alkyl ether, and a phosphate ester salt of polyoxyethylene alkylphenyl ether.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and alkyl ether having a sugar chain as a hydrophilic group.
Examples of the cationic surfactant include alkyl pyridinyl chloride and alkyl ammonium chloride.
Examples of the zwitterionic surfactant include lauryl betaine.

  As the reactive surfactant, it is preferable to use a compound in which any of a methacryloyl group, an acryloyl group, a maleyl group, a vinyl group, and an allyl group is bonded to the inside or the molecular end of the polyoxyalkylene alkyl ether. .

  Specifically, polyoxyethylene nonylpropenyl phenyl ether (trade names: Aqualon RN-20, RN-30, RN-50); polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate (trade names: Aqualon HS-10, BC-0515) , BC-10, BC-20); polyoxyethylene-1- (allyloxymethyl) alkyl ether ammonium sulfate (trade names: Aqualon KH-05, KH-10, and above, both manufactured by Daiichi Kogyo Seiyaku);

  [alpha] -hydro- [omega]-(1-alkoxymethyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl)) (trade names: ADEKA rear soap ER-10, ER-20, ER -30, ER-40); α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene (trade names: Adekalya soap NE-10, NE-20, NE-30, NE-40, NE-50); α-sulfo-ω- (1-alkoxymethyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl) ammonium salt (product) Name: ADEKA rear soap SR-10S, SR-10, SR-20, SR-3025, SE-10N, SE-20N, or more, all manufactured by ADEKA);

2-sodium sulfoethyl methacrylate (trade name: Antox MS-2N); bis (polyoxyethylene polycyclic phenyl ether) methacrylate sulfate (trade name: Antox MS-60); alkoxy polyethylene glycol methacrylate (trade name: Antox LMA) -10, LMA-20, LMA-27); alkoxy polyethylene glycol maleate (trade name: Antox SMH-20, LMH-20, EMH-20, all of which are manufactured by Nippon Emulsifier);
Polyoxyalkylene alkenyl ethers (trade names: Latemul PD-420, PD-430, PD-450; polyoxyalkylene alkenyl ether ammonium sulfates (trade names: Latemul PD-105, all of which are manufactured by Kao);

Vinyl ether alkoxylate (trade name: Emulsogen R208, R307, above, manufactured by Clariant);
Alkyl allylsulfosuccinate (trade name: Eleminol JS-20), polyoxyalkylene methacrylate sulfate ester (trade name: Eleminol RS-3000, all of which are manufactured by Sanyo Chemical);
Unsaturated phosphoric acid ester (trade name: Maxemul 6106, 6112, or more, manufactured by CRODA).

  The resin particles may be composed only of core particles, but preferably have core particles and at least one resin layer covering the core particles. The at least one resin layer is an outermost surface layer of the resin layers and an intermediate layer arbitrarily provided between the core particles and the resin layer. The intermediate layer may be composed of a plurality of layers. The plurality of layers have different compositions in two adjacent layers. That is, the composition of the resin constituting each layer (for example, the type and ratio of monomer units) is different.

  Moreover, it is preferable that the thickness of each resin layer is 1 nm or more. The layer thickness of the resin layer can be calculated from the difference between the particle size before the resin layer is formed and the particle size after the resin layer is formed by measuring the particle size before and after forming the resin layer. it can. Moreover, it can also calculate indirectly from the preparation amount of the monomer used when manufacturing resin particles.

As described above, the configuration of the resin particles includes the following three forms.
(1) Form in which resin particles do not have a resin layer (only core particles; first form)
(2) Form in which resin particles have only one resin layer (core particles + surface layer; second form)
(3) Form in which resin particles have two or more resin layers (core particle + intermediate layer + surface layer; third form)
Hereinafter, a preferable configuration will be described for each of these modes.

[First form (core particles only)]
In the first embodiment, the type of the resin (core polymer) constituting the core particle is not particularly limited, and examples thereof include a resin having a silsesquioxane structure and an ethylenically unsaturated monomer unit. Such a resin can be produced, for example, by copolymerizing the silsesquioxane structure-introducing material and a monomer having only one ethylenically unsaturated bond.

  Although content of the silsesquioxane structure in a core polymer is not specifically limited, It is preferable that they are 5 mass% or more and 40 mass% or less on the basis of the total mass of a core polymer.

  In synthesizing the core polymer, a crosslinking monomer may be used. However, if the amount of the cross-linking monomer is too large, the cross-linking structure between the core polymers increases and the THF insoluble fraction increases, so it is preferable not to use the cross-linking monomer when synthesizing the core polymer.

  The weight average molecular weight (Mw) of the core polymer is preferably 3,000 or more and 1,000,000 or less. In addition, the weight average molecular weight (Mw) said here is a weight average molecular weight of polystyrene conversion obtained by gel permeation chromatography (GPC).

It is preferable that the tetrahydrofuran insoluble fraction (THF insoluble fraction) of the core polymer is 25% by mass or less. When the THF-insoluble fraction is more than 25% by mass, there are many cross-linked structures between the core polymers, and the silsesquioxane structure is less likely to be present on the surface of the recorded image, which has the effect of improving the scratch resistance of the image. You may not get enough. The THF insoluble fraction can be calculated by the following method. THF is added to the dried core particles so that the solid content is 0.5% by mass, and the mixture is stirred for 24 hours to dissolve the solid content in THF. Thereafter, the amount of the core particles remaining without being dissolved in THF is weighed, and the THF insoluble fraction is calculated based on the following formula.
THF insoluble fraction (% by mass)
= {(Mass of remaining core particles) / (total mass of core particles)} × 100

  The glass transition point of the core polymer is preferably −20 ° C. or higher and 200 ° C. or lower. In particular, in the ink jet recording method for recording an image using the ink of the present invention, when the heat fixing step is provided, it is preferable that the glass transition point of the core polymer is equal to or lower than the heating temperature of the heat fixing step. In addition, it is preferable that the heating temperature in a heat fixing process is 25 degreeC or more and 200 degrees C or less.

A specific method for measuring the glass transition point of the core polymer is as follows. First, the core particles are dried at 60 ° C. to obtain a dried product, and 2 mg of the dried product is sealed in an aluminum container. Then, using a differential scanning calorimeter (DSC, trade name “Q1000”, manufactured by TA Instruments), the glass transition point of the core polymer is measured by thermal analysis of the sealed solid product. The temperature program for measuring the glass transition point may be, for example, the following procedures (1) and (2).
(1) After heating to 200 ° C. at 10 ° C./min, the temperature is decreased from 200 ° C. to −50 ° C. at 5 ° C./min.
(2) Next, thermal analysis is performed while increasing the temperature from −50 ° C. to 200 ° C. at a rate of 10 ° C./min.

In the first embodiment, the volume average particle diameter (D ₅₀ ) of the core particles is preferably 20 nm or more and 200 nm or less, more preferably 40 nm or more and 150 nm or less, and particularly preferably 60 nm or more and 100 nm or less. . The volume average particle diameter of the core particles (D ₅₀₎ can be measured the same manner as the volume average particle diameter of the resin particles (D _50), the measurement conditions.

[Second form (core particle + surface layer)]
In the second form, the same core particles as in the first form can be used. In the second embodiment, the ratio of the core polymer in the resin particles is not particularly limited, but is preferably 20% by mass or more and 98% by mass or less, and 40% by mass or more and 96% by mass based on the total mass of the resin particles. More preferably, it is as follows.

  In the second embodiment, the type of resin (shell polymer) constituting the surface layer is not particularly limited, but is preferably a resin having a silsesquioxane structure, an ionic group, and a crosslinked structure. Such a resin can be produced, for example, by copolymerizing the silsesquioxane structure-introducing material, an ionic group-containing monomer, and a crosslinkable monomer. If necessary, a monomer having only one ethylenically unsaturated bond may be further added during the polymerization.

  The content of the ionic group-containing monomer unit in the shell polymer is not particularly limited, but is preferably 5% by mass or more and 60% by mass or less based on the total mass of the shell polymer.

  Note that the shell polymer preferably further has a hydrophilic portion. Examples of the “hydrophilic portion” include a hydroxy group, a methylene oxide group, and an ethylene oxide group in addition to the ionic group described above.

  The content of the crosslinking monomer unit in the shell polymer is not particularly limited, but is preferably 5% by mass or more and 60% by mass or less based on the total mass of the shell polymer.

  The THF-insoluble fraction of the shell polymer is preferably greater than 25% by mass, more preferably greater than 25% by mass and 80% by mass or less. When the THF-insoluble fraction is 25% or less, the shell polymers do not substantially form a crosslinked structure, and the strength of the recorded image may decrease. If the THF insoluble fraction is larger than 80% by mass, the effect of improving the scratch resistance of the image may not be sufficiently obtained. The THF-insoluble fraction of the shell polymer can be calculated by the same method as that for the core polymer.

  In order to make the THF-insoluble fraction of the shell polymer greater than 25%, a crosslinkable monomer may be added when the shell polymer is synthesized. By using the crosslinking monomer, a structure in which the shell polymers are crosslinked is formed, and the THF-insoluble fraction of the shell polymer becomes larger than 25%.

  The weight average molecular weight (Mw) of the shell polymer is preferably 3,000 or more and 1,000,000 or less. The weight average molecular weight (Mw) of the shell polymer can be measured by the same method as that for the core polymer.

  The glass transition point of the shell polymer is preferably −20 ° C. or higher and 200 ° C. or lower, and the glass transition point of the shell polymer is preferably lower than the heating temperature of the heat fixing step. The glass transition point of the shell polymer can be measured by the same method as that for the core polymer.

  The layer thickness of the surface layer in the second embodiment is preferably 1 nm or more, and more preferably 1 nm or more and 30 nm or less.

  In the second embodiment, the ratio of the shell polymer in the resin particles is not particularly limited, but is preferably 1% by mass or more and 90% by mass or less based on the total mass of the resin particles, and is 2% by mass or more and 70% by mass. More preferably, it is as follows. In addition, only 1 type may be sufficient as the shell polymer which comprises a surface layer, and 2 or more types may be sufficient as it.

[Third form (core particle + intermediate layer + surface layer)]
In the third form, the same core particles as in the first form can be used. In the third embodiment, the ratio of the core polymer in the resin particles is not particularly limited, but is preferably 1% by mass or more and 90% by mass or less, based on the total mass of the resin particles, and 5% by mass or more and 60% by mass. More preferably, it is as follows.

  In the third embodiment, the type of the resin (first shell polymer) constituting the intermediate layer is not particularly limited, and examples thereof include a resin having a silsesquioxane structure and an ethylenically unsaturated monomer unit. Such a resin can be produced, for example, by copolymerizing the silsesquioxane structure-introducing material and a monomer having only one ethylenically unsaturated bond.

  The content of the silsesquioxane structure in the first shell polymer is not particularly limited, but is preferably 5% by mass or more and 40% by mass or less based on the total mass of the first shell polymer.

  In synthesizing the first shell polymer, a crosslinking monomer may be used. However, if the amount of the cross-linking monomer is too large, the cross-linking structure between the first shell polymers increases and the THF insoluble content increases, so it is preferable not to use the cross-linking monomer when synthesizing the first shell polymer. .

  The first shell polymer preferably has a tetrahydrofuran insoluble fraction (THF insoluble fraction) of 25% by mass or less. If the THF-insoluble fraction is larger than 25% by mass, the cross-linking structure between the first shell polymers is large, and the silsesquioxane structure is less likely to be present on the surface of the recorded image, improving the scratch resistance of the image. In some cases, sufficient effects cannot be obtained. The THF-insoluble fraction of the first shell polymer can be calculated by the same method as that for the core polymer.

  The weight average molecular weight (Mw) of the first shell polymer is preferably 3,000 or more and 1,000,000 or less. The weight average molecular weight (Mw) of the first shell polymer can be measured by the same method as that for the core polymer.

  The glass transition point of the first shell polymer is preferably −20 ° C. or higher and 200 ° C. or lower, and the glass transition point of the first shell polymer is preferably lower than the heating temperature in the heat fixing step. The glass transition point of the first shell polymer can be measured by the same method as that for the core polymer.

  The thickness of the intermediate layer in the third embodiment is preferably 1 nm or more, and more preferably 1 nm or more and 200 nm or less.

  In the third embodiment, the ratio of the first shell polymer in the resin particles is not particularly limited, but is preferably 1% by mass or more and 90% by mass or less, preferably 5% by mass or more based on the total mass of the resin particles. More preferably, it is 80 mass% or less. In addition, the 1st shell polymer which comprises an intermediate | middle layer may be only 1 type, and 2 or more types may be sufficient as it.

  In the third embodiment, the same resin as the second embodiment can be used as the resin (second shell polymer) constituting the surface layer.

  In the third embodiment, the content of the ionic group-containing monomer unit in the second shell polymer is not particularly limited, but is 5% by mass or more and 60% by mass or less based on the total mass of the second shell polymer. Is preferred.

  In the third embodiment, the content of the crosslinking monomer unit in the second shell polymer is not particularly limited, but is preferably 5% by mass or more and 60% by mass or less based on the total mass of the second shell polymer.

  In the third embodiment, the weight average molecular weight (Mw) of the second shell polymer is preferably 3,000 or more and 1,000,000 or less. The weight average molecular weight (Mw) of the second shell polymer can be measured by the same method as that for the core polymer.

  In the third embodiment, the glass transition point of the second shell polymer is preferably −20 ° C. or higher and 200 ° C. or lower, and the glass transition point of the second shell polymer is lower than the heating temperature of the heat fixing step. Preferably there is. The glass transition point of the second shell polymer can be measured by the same method as that for the core polymer.

  In the third embodiment, the ratio of the second shell polymer in the resin particles is not particularly limited, but is preferably 1% by mass or more and 90% by mass or less, based on the total mass of the resin particles, and 2% by mass or more. More preferably, it is 70 mass% or less. In addition, only 1 type may be sufficient as the 2nd shell polymer which comprises a surface layer, and 2 or more types may be sufficient as it.

(Method for producing resin particles)
As a method for producing resin particles, any known method can be used as long as it is a method capable of producing resin particles having the configuration of the present invention. Examples thereof include an emulsion polymerization method, a pre-emulsion polymerization method, a seed polymerization method, and a phase inversion emulsification method.

  Here, as a representative example, a method for producing resin particles composed of core particles and one resin layer (surface layer) will be described. First, in the first step, a dispersion of core particles composed of a core polymer having a silsesquioxane structure is obtained by emulsion polymerization of a silsesquioxane structure-introducing material having a polymerizable functional group and another monomer. obtain. Next, in the second step, an emulsion containing water, a silsesquioxane structure-introducing material having a polymerizable functional group, another monomer, and a surfactant is added to the dispersion and polymerized to form a shell polymer. And the surface of the core particle is coated with the shell polymer. By such a method, resin particles composed of core particles and a surface layer are obtained. Furthermore, the resin particle which has an intermediate | middle layer can also be manufactured by performing the process of forming another resin layer, before forming a surface layer.

<Color material>
The ink of the present invention may further contain a color material. Examples of the color material include pigments and dyes. Any conventionally known pigments and dyes can be used. In the present invention, it is preferable to use a pigment from the viewpoint of imparting water resistance to the image. As the pigment, it is preferable to use carbon black or an organic pigment. Moreover, a pigment can be used individually by 1 type or in combination of 2 or more types. The content (% by mass) of the coloring material in the ink is preferably 0.1% by mass or more and 15.0% by mass or less, and 1.0% by mass or more and 10.0% by mass or less based on the total mass of the ink. Further preferred.

  When a pigment is used as a coloring material, the pigment is dispersed by using a resin dispersion type pigment using a resin as a dispersant (a resin dispersion type pigment using a resin dispersant; a microcapsule in which the particle surface of the pigment is coated with a resin. Type pigments). Examples of the resin-dispersed pigment include a resin-bonded self-dispersed pigment in which an organic group containing a resin is chemically bonded to the pigment particle surface. Furthermore, as another dispersion method, a self-dispersion type pigment (self-dispersion pigment) in which a hydrophilic group is introduced on the particle surface of the pigment can be mentioned. Of course, in the water-based ink of the present invention, pigments having different dispersion methods can be used in combination.

  The resin used as the dispersant in the resin dispersion type pigment preferably has both a hydrophilic part and a hydrophobic part. Specifically, an acrylic resin polymerized using a monomer having a carboxy group such as acrylic acid or methacrylic acid; a urethane resin polymerized using a diol having an anionic group such as dimethylolpropionic acid; Moreover, it is preferable that the acid value of resin used as a dispersing agent is 50 mgKOH / g or more and 300 mgKOH / g or less.

  Moreover, it is preferable that the polystyrene conversion weight average molecular weight (Mw) obtained by GPC of resin used as a dispersing agent is 1,000 or more and 15,000 or less. The content (% by mass) of the resin dispersant in the ink is 0.1% by mass to 10.0% by mass, and further 0.2% by mass to 4.0% by mass based on the total mass of the ink. % Or less is preferable. Moreover, it is preferable that content (mass%) of a resin dispersing agent is 0.1 time or more and 1.0 time or less by mass ratio with respect to content (mass%) of a pigment.

  When using a dye as a color material, it is preferable to use a water-soluble dye having an anionic group such as a sulfonic acid group or a carboxy group. Specifically, an acid dye, a direct dye described in the color index (COLOUR INDEX), And dyes and reactive dyes. Moreover, even if it is a dye which is not described in a color index, if it is a dye which has at least anionic groups, such as a sulfonic acid group and a carboxy group, it can be used conveniently.

(Aqueous medium)
The ink of the present invention preferably contains water or an aqueous medium that is a mixed solvent of water and a water-soluble organic solvent. The content (mass%) of the water-soluble organic solvent in the ink is preferably 3.0 mass% or more and 50.0 mass% or less based on the total mass of the ink. Any conventionally used water-soluble organic solvent can be used. Examples thereof include alcohols, glycols, alkylene glycols, polyethylene glycols, nitrogen-containing compounds, and sulfur-containing compounds. These water-soluble organic solvents can be used alone or in combination of two or more as required. It is preferable to use deionized water (ion exchange water) as the water. The content (% by mass) of water in the ink is preferably 50.0% by mass or more and 95.0% by mass or less based on the total mass of the ink.

(Other ingredients)
In addition to the above components, the ink of the present invention is a water-soluble organic compound that is solid at room temperature, such as polyhydric alcohols such as trimethylolpropane and trimethylolethane, and urea derivatives such as urea and ethyleneurea. May be contained. Furthermore, the ink of the present invention may contain a surfactant, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, an anti-reduction agent, an evaporation accelerator, a chelating agent, and the like, if necessary. Various additives such as a resin other than the resin particles may be contained. In particular, when a color material is contained in the ink, it is more preferable to adjust the pH to 6 or more and 10 or less.

<Ink cartridge>
The ink cartridge of the present invention is an ink cartridge having an ink storage portion for storing ink, and the ink stored in the ink storage portion is the ink of the present invention. As for the structure of the ink cartridge, the ink storage portion includes an ink storage chamber that stores liquid ink and a negative pressure generation member storage chamber that stores a negative pressure generation member that holds the ink therein by a negative pressure. Things. Alternatively, the ink storage unit may be an ink cartridge that does not have an ink storage chamber that stores liquid ink and that holds the entire storage amount by a negative pressure generating member. Furthermore, the ink cartridge may be configured to have an ink storage portion and a recording head.

<Inkjet recording method>
The ink jet recording method of the present invention is an ink jet recording method in which ink is ejected from a recording head by the action of thermal energy, and the ink of the present invention is used as the ink. The “recording” in the present invention refers to a mode in which ink is applied to a permeable recording medium and recording is performed, and ink is applied to a non-permeable recording medium (base material) such as a glass plate, a plastic plate, or a plastic film. And a mode of recording by assigning. Examples of the permeable recording medium include plain paper and so-called glossy paper having a porous ink-receiving layer containing an inorganic pigment and a binder on the surface of a gas-permeable support (paper or the like). .

  FIG. 1 is a perspective view of a mechanism portion of the ink jet recording apparatus. When performing paper feeding, first, a predetermined number of recording media are sent to a nip portion including a paper feeding roller and a separation roller in a paper feeding unit including a paper feeding tray. The recording medium is separated at the nip portion, and only the uppermost recording medium is conveyed. The recording medium sent to the transport unit is guided by the pinch roller holder M3000 and the paper guide flapper, and is sent to the roller pair of the transport roller M3060 and the pinch roller M3070. A roller pair composed of a conveyance roller M3060 and a pinch roller M3070 is rotated by driving of an LF motor, and the recording medium is conveyed on the platen M3040 by this rotation.

  When recording an image, the carriage unit disposes the recording head at a target image forming position and ejects ink onto the recording medium in accordance with a signal from the electric substrate. In the ink jet recording apparatus, the main scanning in which the carriage M4000 scans in the column direction while recording by the recording head and the sub-scan in which the recording medium is transported in the row direction by the transport roller M3060 are alternately repeated, thereby recording the recording medium. An image is formed on. Finally, the recording medium on which the image is formed is sandwiched by the nip between the first paper discharge roller M3110 and the spur at the paper discharge unit, conveyed, and discharged to the paper discharge tray. In the figure, E0014 is an electric board, M5000 is a pump, and M5010 is a cap.

  FIG. 2 is a perspective view showing a state where the ink cartridge H1900 is mounted on the head cartridge H1000. FIG. 2 shows a state where ink cartridges H1900 corresponding to a plurality of inks are independently prepared. Each ink cartridge H1900 is detachable from the head cartridge H1000. The ink cartridge H1900 can be attached and detached while the head cartridge H1000 is mounted on a carriage (reference numeral M4000 in FIG. 1). Note that reference numeral H1001 in the figure denotes a recording head.

  Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples. The present invention is not limited in any way by the following examples as long as the gist thereof is not exceeded. In the description of the following examples, “part” is based on mass unless otherwise specified.

The meanings of the following explanations and the abbreviations in the table are as follows.
SSQ-8CH: 1,3,5,7,9,11,13,15-octacyclohexylpentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13 ] octasiloxane. Silsesquioxane structure-introducing material having no polymerizable functional group and no polysiloxane structure SSQ-MA: 3- (3,5,7,9,11,13,15-heptaisobutylpentacyclo [9.5. 1.1 ^3,9 .1 ^5,15 .1 ^7,13 ] ^{octasiloxane-} 1-yl) propyl methacrylate. Silsesquioxane structure-introducing material having a methacryloyl group as a polymerizable functional group (all of these are made by Sigma-Aldrich)
MAC-SQ TM-100: Trade name of silsesquioxane structure-introducing material having methacryloyl group as polymerizable functional group MAC-SQ SI-20: Polysiloxane structure having methacryloyl group as polymerizable functional group Name of silsesquioxane structure-introduced material having slag (all are manufactured by Toagosei Co., Ltd.)
・ Aqualon KH-05: Trade name of polyoxyethylene-1- (allyloxymethyl) alkyl ether ammonium sulfate (5EO adduct) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ・ Nikkool BC15: Polyoxyethylene (15) cetyl ether manufactured by Nikko Chemicals Product name of ADEKA rear soap ER-20: Product of α-hydro-ω- (1-alkoxymethyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl)) manufactured by ADEKA Name BMA: n-butyl methacrylate n-HD: n-hexadecane MAA: methacrylic acid 1,4-BDDMA: 1,4-butanediol dimethacrylate AMBN: 2,2′-azobis- (2-methyl Butyronitrile)
・ KPS: Potassium persulfate

<Preparation of resin particle dispersion>
A resin particle dispersion was prepared by the following method. The content of the silsesquioxane structure was calculated by the method described above.

(Preparation of resin particle dispersion 1)
n-butyl methacrylate (BMA): 27.0 parts, MAC-SQ TM-100: 8.0 parts, n-hexadecane (n-HD) as a hydrophobe: 2.0 parts, and 2,2′-azobis -(2-Methylbutyronitrile) (AMBN): 2.0 parts were mixed and stirred for 30 minutes. This mixed solution was added dropwise to 61.0 parts of a 5.0 mass% aqueous solution of Nikkol BC15 and stirred for 30 minutes. Next, using an ultrasonic irradiator (trade name: S-150D Digital Sonifier, manufactured by Branson), the mixed solution was dispersed under conditions of 400 W, 20 kHz, 3 hours, and then polymerized at 80 ° C. for 4 hours in a nitrogen atmosphere. Reaction was performed to form resin particles (core particles). Thereafter, the reaction solution was cooled to room temperature, and ion exchange water and an aqueous potassium hydroxide (KOH) solution were added to obtain a resin particle dispersion 1 having a resin content of 15% by mass and a pH of 8.5. The said resin particle is a resin particle which is comprised from the core polymer whose content of a silsesquioxane structure is 19.0 mass%, and does not have a resin layer (it consists only of core particles). The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersion 2)
n-butyl methacrylate (BMA): 27.0 parts, MAC-SQ TM-100: 8.0 parts, n-hexadecane (n-HD) as a hydrophobe: 2.0 parts, and 2,2′-azobis -(2-Methylbutyronitrile) (AMBN): 2.0 parts were mixed and stirred for 30 minutes. This mixed solution was added dropwise to 61.0 parts of a 5.0 mass% aqueous solution of Nikkol BC15 and stirred for 30 minutes. Next, using an ultrasonic irradiator (trade name: S-150D Digital Sonifier, manufactured by Branson), the dispersion was carried out under conditions of 400 W, 20 kHz, 3 hours, and then a polymerization reaction was performed at 80 ° C. for 4 hours in a nitrogen atmosphere. A dispersion of core particles was obtained.

  Next, 73.0 parts of the core particle dispersion obtained above was heated to 75 ° C. in a nitrogen atmosphere, and 0.1 part of potassium persulfate (KPS) was added thereto. In a separate container, ion-exchanged water: 7.9 parts, n-butyl methacrylate (BMA): 7.0 parts, MAC-SQ TM-100: 4.0 parts, methacrylic acid (MAA): 3.0 parts, 1 , 4-butanediol dimethacrylate (1,4-BDDMA): 2.0 parts and Aqualon KH-05: 3.0 parts were mixed and emulsified, and the resulting emulsion was added to the core particle dispersion. It dripped over time and performed the polymerization reaction and formed the resin layer (surface layer) on the surface of the said core particle. After the dropwise addition, the dispersion was heated to 85 ° C. and stirred for 2 hours to conduct a chasing polymerization reaction. Thereafter, the reaction solution was cooled to room temperature, and ion exchange water and an aqueous potassium hydroxide (KOH) solution were added to obtain a resin particle dispersion 2 having a resin content of 15% by mass and a pH of 8.5. The resin particles include a core particle composed of a core polymer having a silsesquioxane structure content of 19.0% by mass and a shell polymer having a silsesquioxane structure content of 20.9% by mass. It is a resin particle having a single resin layer (surface layer). The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersion 3)
As shown in Table 1 below, the resin content was 15% by mass, pH 8 in the same manner as in the resin particle dispersion 2 except that the amount of monomer and the type and amount of silsesquioxane structure-introducing material were changed. 5 resin particle dispersion 3 was obtained. The resin particles use SSQ-8CH having no polymerizable functional group as a silsesquioxane structure-introducing material when forming the resin layer, and silsesquioxane that is not chemically bonded to the shell polymer. It has a structure. The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersions 4 to 6)
As shown in Table 1 below, the resin content was 15% by mass, pH 8 in the same manner as in the resin particle dispersion 2 except that the amount of monomer and the type and amount of silsesquioxane structure-introducing material were changed. 5 resin particle dispersions 4 to 6 were obtained. These are resin particles having core particles and one resin layer (surface layer). The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersion 7)
n-butyl methacrylate (BMA): 25.0 parts, MAC-SQ SI-20: 10.0 parts, n-hexadecane (n-HD) which is hydrophobe: 2.0 parts, and 2,2′-azobis -(2-Methylbutyronitrile) (AMBN): 2.0 parts were mixed and stirred for 30 minutes. This mixed solution was added dropwise to 61.0 parts of a 5.0 mass% aqueous solution of Nikkol BC15 and stirred for 30 minutes. Next, using an ultrasonic irradiator (trade name: S-150D Digital Sonifier, manufactured by Branson), the dispersion was carried out under conditions of 400 W, 20 kHz, 3 hours, and then a polymerization reaction was performed at 80 ° C. for 4 hours in a nitrogen atmosphere. A dispersion of core particles was obtained.

  Next, 73.0 parts of the core particle dispersion obtained above was heated to 75 ° C. in a nitrogen atmosphere, and potassium persulfate (KPS): 0.07 part was added thereto. In a separate container, ion exchange water: 5.9 parts, n-butyl methacrylate (BMA): 6.0 parts, MAC-SQ SI-20: 4.0 parts, and Aqualon KH-05: 1.5 parts are mixed. After emulsification, the emulsion was dropped into the dispersion of the core particles over 1 hour, and a polymerization reaction was performed to form a resin layer (intermediate layer) on the surface of the core particles. After the dropwise addition, the dispersion was heated to 85 ° C. and stirred for 2 hours to conduct a follow-up polymerization reaction to obtain a dispersion of resin particles (core particles + intermediate layer).

  Further, the dispersion of the resin particles (core particles + intermediate layer) obtained above was heated to 75 ° C. in a nitrogen atmosphere, and potassium persulfate (KPS): 0.03 part was added thereto. In a separate container, ion-exchanged water: 2.0 parts, n-butyl methacrylate (BMA): 2.0 parts, methacrylic acid (MAA): 2.0 parts, 1,4-butanediol dimethacrylate (1,4- (BDDMA): 3.0 parts and Aqualon KH-05: 0.5 part were mixed and emulsified, and then the emulsion was added dropwise to the dispersion of the resin particles over 30 minutes to conduct a polymerization reaction, and A resin layer (surface layer) was formed on the surface of the resin particles (core particle + intermediate layer). After the dropwise addition, the dispersion was heated to 85 ° C. and stirred for 2 hours to conduct a chasing polymerization reaction. Thereafter, the reaction solution was cooled to room temperature, and ion-exchanged water and an aqueous potassium hydroxide (KOH) solution were added to obtain a resin particle dispersion 7 having a resin content of 15% by mass and a pH of 8.5. The resin particles include a core particle composed of a core polymer having a silsesquioxane structure content of 23.8% by mass and two resin layers (silsesquioxane structure content of 34.6% by mass). It is a resin particle having an intermediate layer made of a certain first shell polymer and a surface layer not containing a silsesquioxane structure. The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersion 8)
As shown in Table 1 below, the resin content was 15 masses in the same manner as in the resin particle dispersion 7 except that the reactive surfactant was changed from AQUALON KH-05 to ADEKA rear soap ER-20. %, PH 8.5 resin particle dispersion 8 was obtained. The resin particles include a core particle composed of a core polymer having a silsesquioxane structure content of 23.8% by mass and two resin layers (silsesquioxane structure content of 34.6% by mass). It is a resin particle having an intermediate layer made of a certain first shell polymer and a surface layer not containing a silsesquioxane structure. The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersion 9)
As shown in Table 1 below, the resin content was changed in the same manner as in the resin particle dispersion 2 except that the type and amount of the monomer were changed and the silsesquioxane structure-introducing material was not used. A resin particle dispersion 9 of 15% by mass and pH 8.5 was obtained. The resin particles are resin particles that have a core particle and one resin layer (surface layer), and do not contain a resin having a silsesquioxane structure in any of the core particles and the resin layer. The results are shown in Tables 1 and 2.

(Preparation of resin particle dispersion 10)
As shown in Table 1 below, the resin content was changed in the same manner as in the resin particle dispersion 7 except that the type and amount of the monomer were changed and the silsesquioxane structure introduction material was not used. A resin particle dispersion 10 having a mass of 15% by mass and a pH of 8.5 was obtained. The resin particle has a core particle and two resin layers (intermediate layer and surface layer), and the resin does not contain a resin having a silsesquioxane structure in any of the core particle and the resin layer. Particles.

<Preparation of pigment dispersion>
A styrene-ethyl acrylate-acrylic acid copolymer having an acid value of 150 mgKOH / g and a weight average molecular weight of 8,000 is neutralized with a 10% by mass aqueous potassium hydroxide solution, and the resin content is 20.0% by mass. A resin aqueous solution was obtained. And 30 parts of resin aqueous solution, 20 parts of carbon black monak 1100 (product made from Cabot), and 50 parts of ion-exchange water were mixed. This mixture was dispersed for 5 hours using a batch type vertical sand mill (manufactured by IMEX) filled with 200 parts of zirconia beads having a particle diameter of 0.3 mm. Thereafter, the dispersion was centrifuged to remove coarse particles, and pressure filtration was performed with a micro filter (manufactured by Fujifilm) having a pore size of 3.0 μm. By the above-described method, a pigment dispersion liquid (pigment content is 20% by mass and resin content is 6% by mass) in a state where carbon black is dispersed in water by the resin is obtained.

<Preparation of ink>
The resin particle dispersion obtained above was mixed with the following components to prepare ink.
The meanings of the following explanations and the abbreviations in the table are as follows.
-GLY: Glycerin-DEG: Diethylene glycol-Acetylenol E100: Product name of nonionic surfactant (POE (10) acetylene glycol) manufactured by Kawaken Fine Chemicals

Example 1
Resin particle dispersion 1: 70.0 parts, pigment dispersion: 10.0 parts, glycerin (GLY): 10.0 parts, diethylene glycol (DEG): 4.0 parts, acetylenol E100: 1 0.0 part and 5.0 parts of ion-exchanged water were mixed. After these were sufficiently stirred and dispersed, this dispersion was subjected to pressure filtration using a microfilter (manufactured by Fuji Film) having a pore size of 3.0 μm to prepare the ink of Example 1.

(Examples 2 to 8 and Comparative Examples 1 and 2)
As shown in Table 3 below, inks of Examples 2 to 8 and Comparative Examples 1 to 2 were obtained in the same manner as in Example 1 except that the type of the resin particle dispersion was changed.

<Evaluation>
(Evaluation of scratch resistance of images)
Image formation was performed using an inkjet recording apparatus (trade name: PIXUS Pro 9500, manufactured by Canon Inc.). In the ink jet recording apparatus, an image recorded under the condition that the resolution is 600 dpi × 600 dpi and eight 3.5 ng ink droplets are applied to a unit area of 1/600 inch × 1/600 inch has a recording duty of 100%. Is defined as

Each ink obtained above was filled in an ink cartridge and mounted on the ink jet recording apparatus. A solid image (200 mm × 200 mm) with a recording duty of 100% was recorded on A2 coated paper (trade name: OK top coat + (plus), basis weight 127.9 g, manufactured by Oji Paper). The image was subjected to a friction test under the conditions of a load of 500 g and 10 reciprocations using a Gakushin type friction tester (trade name: wear resistance tester, manufactured by Imoto Seisakusho) in accordance with JIS L 0849. By visually observing the image after the friction test, the scratch resistance of the image was evaluated. In this example, AA to B were set as preferable levels and C was set as an unacceptable level according to the following evaluation criteria. The evaluation results are shown in Table 4.
AA: The image was not scratched. A: The image was slightly scratched, but the white background of the recording medium was not visible. B: The image was scratched and the recording medium was slightly white. Although it was visible, it was an inconspicuous level. C: The image was scratched and the white background of the recording medium was visible.

E0014: Electric substrate H1000: Head cartridge H1001: Recording head H1900: Ink cartridge M3000: Pinch roller holder M3040: Platen M3060: Transport roller M3070: Pinch roller M3110: First paper discharge roller M4000: Carriage M5000: Pump M5010: Cap

Claims (9)

An ink jet ink containing resin particles,
The ink, wherein the resin particles include a resin having a silsesquioxane structure. The resin particles have a core-shell structure including a core polymer and a shell polymer;
The ink according to claim 1, wherein at least one of the core polymer and the shell polymer has the silsesquioxane structure. Both the core polymer and the shell polymer have the silsesquioxane structure,
The ink according to claim 2, wherein the content of the silsesquioxane structure in the core polymer is different from the content of the silsesquioxane structure in the shell polymer. The resin particles have a core-shell structure including a core polymer, a first shell polymer constituting an intermediate layer, and a second shell polymer constituting a surface layer;
At least one selected from the core polymer, the first shell polymer, and the second shell polymer has the silsesquioxane structure,
The silsesquioxane structure content in the second shell polymer is any of the silsesquioxane structure content in the core polymer and the silsesquioxane structure content in the first shell polymer. The ink according to claim 1, which is smaller than the ink.   The ink according to claim 4, wherein the second shell polymer does not have the silsesquioxane structure.   The ink according to any one of claims 1 to 5, wherein the resin having a silsesquioxane structure further has at least one structure selected from a dialkylpolysiloxane structure and an alkylarylpolysiloxane structure. An ink jet ink containing resin particles,
An ink, wherein the resin particles encapsulate a compound having a silsesquioxane structure. An ink cartridge having an ink containing portion for containing ink,
The ink cartridge according to claim 1, wherein the ink stored in the ink storage unit is the ink according to claim 1. An inkjet recording method for ejecting ink from a recording head by the action of thermal energy,
An ink jet recording method using the ink according to any one of claims 1 to 7 as the ink.

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