Copolymer, ink, ink storage container, image forming method, image forming apparatus and solar cell back sheet

Abstract

To provide a colorant dispersion having excellent storage stability and a copolymer capable of producing an ink having excellent storage stability and redispersibility.SOLUTION: There is provided a copolymer having a structural unit represented by the following general formula (1), a structural unit having an anionic group and a structural unit having a naphthyl group and / or a pyridyl group. (In formula (1), R1 represents hydrogen or a methyl group, R2 represents a methyl group, CH2=CH-COO- or CH2=C(CH3)-COO- and n is an integer in which the weight average molecular weight of the structural unit represented by general formula (1) is 420 or more and 120,000 or less.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a copolymer, an ink, an ink container, an image forming method, an image forming apparatus, and a solar cell backsheet. [Background technology]

[0002] Inkjet printers are widely used as printers for printing on paper media. When printing on media other than paper media (for example, media such as transparent or colored plastic films and colored fabrics), a white ink with high hiding power is required in addition to black ink, yellow ink, magenta ink, and cyan ink.

[0003] Rutile-type titanium oxide, which has a high refractive index, is used as a pigment for white ink with high hiding power. As a dispersant for the titanium oxide, for example, a carboxyl group-containing AB block copolymer of an AB block type, which is composed of methacrylate containing an aliphatic cyclic alkyl group having at least 6 carbon atoms and methacrylic acid, has been proposed (for example, see Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a colorant dispersion having excellent storage stability, and a copolymer capable of producing an ink having excellent storage stability and redispersibility. [Means for solving the problem]

[0005] The copolymer of the present invention as a means for solving the above problems is as follows: That is, the copolymer has a structural unit represented by the following general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group.

[0006] [ka] (In the general formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group, "CH2=CH-COO-", or "CH2=C(CH3)-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.) Effect of the Invention

[0007] According to the present invention, it is possible to provide a colorant dispersion having excellent storage stability, and a copolymer capable of producing an ink having excellent storage stability and redispersibility. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an example of an image forming apparatus of the present invention. [Diagram 2] FIG. 2 is a schematic diagram illustrating an example of an ink cartridge. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Rutile titanium dioxide used in conventional white inks with high hiding power has a specific gravity of 4.17 g / mL, and is known to settle in the ink over time and eventually separate. If the original dispersion state is restored by stirring or shaking when using the white ink, there is no problem in use, but there is a concern that titanium dioxide deposited in the lower layer of the ink may aggregate and the dispersion state may not be restored. In addition, there is a concern that the ink may not return to its original dispersion state, resulting in an increase in the viscosity of the ink, a decrease in the white hiding power, and poor discharge.

[0010] The conventional dispersants described in Patent Document 1 do not provide sufficient ink storage stability or colorant redispersibility, and further improvements are desired.

[0011] As a result of extensive research, the present inventors have found that by using a copolymer having a structural unit represented by general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group, it is possible to obtain a colorant dispersion having excellent storage stability, and an ink having excellent storage stability and redispersibility.

[0012] Furthermore, they discovered that a film in which colorants such as titanium oxide are uniformly dispersed without aggregation can be obtained from an ink containing water, a colorant, and the copolymer, and that by applying the obtained film to a solar cell backsheet as a protective layer, a solar cell backsheet with excellent weather resistance can be obtained.

[0013] The present invention will now be described in detail.

[0014] (copolymer) The copolymer of the present invention has a structural unit represented by the following general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group, and may also have structural units derived from other polymerizable monomers, as necessary.

[0015] [ka] (In the general formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group, "CH2=CH-COO-", or "CH2=C(CH3)-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.)

[0016] For convenience, the terms "first monomer", "second monomer", and "third monomer" are used in this specification. The "structural unit represented by general formula (1)" refers to a structural unit derived from the first monomer, the "structural unit having an anionic group" refers to a structural unit derived from the second monomer, and the "structural unit having a naphthyl group and / or a pyridyl group" refers to a structural unit derived from the third monomer.

[0017] <Structural unit represented by general formula (1)> The structural unit represented by the following general formula (1) is a structural unit derived from the first monomer, as described above.

[0018] [ka] (In the general formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group, "CH2=CH-COO-", or "CH2=C(CH3)-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.)

[0019] In the copolymer having the structural unit represented by the general formula (1), the structural unit having the anionic group, and the structural unit having the naphthyl group and / or the pyridyl group, the structural unit represented by the general formula (1) derived from the first monomer, i.e., the polydimethylsiloxane chain, imparts releasability to the copolymer. Therefore, when the copolymer is adsorbed on the pigment surface, the pigments are prevented from agglomerating, and an ink with high redispersibility can be prepared.

[0020] The content of the structural unit represented by the general formula (1) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 mass % or more and 30 mass % or less, and more preferably 3 mass % or more and 20 mass % or less, based on the total amount of the copolymer.

[0021] The content of the structural unit represented by the general formula (1) in the present invention is 1 H-NMR, 13 It can be determined by a combination of C-NMR, GC-MS, LC-MS, and LC-MS / MS.

[0022] The first monomer may be a synthesized one or a commercially available product, such as X-22-2404, KF-2012, X-22-2426, X-22-2445, X-22-164A, and X-22-164E (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0023] <Structural Unit Having Anionic Group> The structural unit having an anionic group is a structural unit derived from the second monomer, as described above. The structural unit having the anionic group induces electrostatic repulsion between copolymer molecules, which can suppress aggregation of color materials described below, making it possible to prepare an ink with high redispersibility and storage stability.

[0024] The anionic group is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a carboxyl group, a sulfonyl group, a phosphorus-containing group (a phosphoric acid group, or a phosphonic acid group), etc. Among these, a carboxyl group is preferred from the viewpoint of storage stability of the ink.

[0025] The second monomer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the second monomer include unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers, and unsaturated phosphoric acid monomers. Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid. Examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid. Examples of such unsaturated phosphate monomers include vinyl phosphonic acid, vinyl phosphate, bis(methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, and dibutyl-2-acryloyloxyethyl phosphate. These may be used alone or in combination of two or more.

[0026] The second monomer and the structural unit having an anionic group may be neutralized with a base. The base is not particularly limited and can be appropriately selected depending on the purpose. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, triethylmethylammonium hydroxide, tributylmethylammonium hydroxide, trioctylmethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, propyltrimethylammonium hydroxide, hexyltrimethylammonium hydroxide, octyltrimethylammonium hydroxide, nonyltrimethylammonium hydroxide, decyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide, Examples of the ammonium hydroxide include tetradecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, octadecyltrimethylammonium hydroxide, didodecyldimethylammonium hydroxide, ditetradecyldimethylammonium hydroxide, dihexadecyldimethylammonium hydroxide, dioctadecyldimethylammonium hydroxide, ethylhexadecyldimethylammonium hydroxide, aqueous ammonia, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, dimethylethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, isopropanolamine, morpholine, N-methylmorpholine, N-methyl-2-pyrrolidone, and 2-pyrrolidone. These may be used alone or in combination of two or more. The neutralization with a base may be carried out when the second monomer is copolymerized, or when the copolymer is dissolved.

[0027] The content of the structural unit having the anionic group is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5.0 mass% or more and 35.0 mass% or less, and more preferably 15.0 mass% or more and 25.0 mass% or less, based on the total amount of the copolymer. If the content of the structural unit having the anionic group is within the above-mentioned preferred range, it is suitable from the viewpoint of solubility in water and dispersion stability.

[0028] The content of the structural unit having an anionic group in the present invention is 1 H-NMR, 13 The content of anionic groups in the copolymer of the present invention can be determined by a combination of C-NMR, GC-MS, LC-MS, and LC-MS / MS. The content of anionic groups in the copolymer of the present invention can also be determined by a neutralization titration method in which an alkaline solution is dropped into a solution in which a titration indicator such as phenolphthalein is added to a solution in which a certain amount of the copolymer of the present invention is dissolved.

[0029] The second monomer may be a synthesized one or a commercially available product. Examples of the commercially available second monomer include acrylic acid (AA) (manufactured by Tokyo Chemical Industry Co., Ltd.) and methacrylic acid (MA) (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0030] <Structural Unit Having Naphthyl Group and / or Pyridyl Group> The structural unit having a naphthyl group and / or a pyridyl group is a structural unit derived from the third monomer, as described above.

[0031] In the copolymer having structural units having a naphthyl group and / or a pyridyl group, the naphthyl group and / or the pyridyl group is easily adsorbed to the surface of pigment particles, and thus a pigment dispersion and an ink having excellent storage stability are provided. In particular, the pyridyl group present at the terminal functions as a Lewis base, thereby improving the adsorption force to the particle surfaces of titanium oxide, titanium oxide surface-treated with alumina, barium sulfate, and the like.

[0032] The structural unit having a naphthyl group and / or a pyridyl group preferably has a structure represented by the following general formula (2).

[0033] [ka] (In the general formula (2), R3 represents hydrogen or a methyl group, L1 represents "-COO- (bonded to X)", "-CONH- (bonded to X)", or a bond, X represents a hydrocarbon group having 2 to 10 carbon atoms or a hydrocarbon group containing oxygen and having 2 to 10 carbon atoms, L2 represents "-O-" or "-NH-", Y represents a hydrocarbon group having 2 to 12 carbon atoms or a bond, L3 represents "-NHCO- (bonded to Z)", "-OCO- (bonded to Z)", "-O-", or "-(CH2)n-", n represents an integer of 1 to 3, and Z represents a naphthyl group or a pyridyl group.)

[0034] The naphthyl group and / or pyridyl group in the structural unit having a naphthyl group and / or pyridyl group is located away from the main chain of the copolymer, and therefore is less susceptible to the inhibition of adsorption to the colorant by other components involved in the copolymerization (such as structural units having an anionic group). Furthermore, the linking group X in the structural unit having a naphthyl group and / or a pyridyl group, and the "-NH-CO-NH- group" or "-NH-COO- group" bonded to the linking group Y impart water solubility to the copolymer. Therefore, the dispersion stability of the colorant can be improved, and an ink with high storage stability can be obtained. That is, when a colorant dispersion in which a colorant is dispersed in water is prepared as described below, a colorant dispersion with high dispersibility and long-term stability can be prepared by using the copolymer of the present invention.

[0035] The third monomer having a naphthyl group is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include acrylic acid 4-(2-(naphthalen-1-yl)acetoyloxy)butyl ester, 1-naphthoic acid 2-(acryloyloxy)ethyl ester, methacrylic acid 2-(naphthalen-2-yl)-2-oxoethyl ester, methacrylic acid 4-hydroxy-4-(naphthalen-1-yl)butyl ester, and acrylic acid 2-(2-(naphthalen-1-yl)ethoxy)ethyl ester.

[0036] The third monomer having a pyridyl group is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include methacrylic acid 2-(2-pyridinyldithio)ethyl ester, isonicotinic acid 2-(methacryloyloxy)ethyl ester, and acrylic acid 3-(pyridin-4-yl)propyl ester.

[0037] The content of the structural units having a naphthyl group and / or a pyridyl group is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 35.0 mass% or more and 94.0 mass% or less, and more preferably 55.0 mass% or more and 82.0 mass% or less, based on the total amount of the copolymer.

[0038] The content of the structural unit having a naphthyl group and / or a pyridyl group in the present invention is 1 H-NMR, 13 It can be determined by a combination of C-NMR, GC-MS, LC-MS, and LC-MS / MS.

[0039] The method for obtaining the structural unit having a naphthyl group and / or a pyridyl group is not particularly limited and can be appropriately selected depending on the purpose. For example, the following methods can be mentioned. [One example of a method for obtaining a structural unit having a naphthyl group and / or a pyridyl group] Pyridyl carboxylic acid (A-1) is subjected to a condensation reaction with an excess amount of diol to obtain pyridine carboxylic acid hydroxyalkyl ester (A-2).

[0040] [ka]

[0041] Next, an isocyanate compound (A-3) having an acrylic group or the like is reacted with the (A-2) to obtain a monomer (A-4).

[0042] [ka]

[0043] <Structural units derived from other polymerizable monomers> The copolymer of the present invention may contain structural units derived from other polymerizable monomers in addition to the structural units derived from the first monomer, the structural units derived from the second monomer, and the structural units derived from the third monomer. The other polymerizable monomers are not particularly limited and may be appropriately selected depending on the purpose. Examples of the other polymerizable monomers include polymerizable hydrophobic monomers, polymerizable hydrophilic monomers, and polymerizable surfactants. In this specification, the "other polymerizable monomer" may be referred to as "other monomer".

[0044] <<Polymerizable hydrophobic monomers>> The polymerizable hydrophobic monomer is not particularly limited and can be appropriately selected depending on the purpose. For example, it is possible to use unsaturated ethylene monomers having an aromatic ring, such as α-methylstyrene, 4-t-butylstyrene, and 4-chloromethylstyrene; methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, dimethyl maleate, dimethyl itaconate, dimethyl fumarate, lauryl (meth)acrylate (C12), tridecyl (meth)acrylate (C13), tetradecyl (meth)acrylate (C14), pentadecyl (meth)acrylate (C15), hexadecyl (meth)acrylate (C16), heptadecyl (meth)acrylate (C17), nonadecyl (meth)acrylate (C19), eicosyl (meth)acrylate (C20), (meth)acrylate (C21), (meth)acrylate (C22), (meth)acrylate (C23), (meth)acrylate (C24), (meth)acrylate (C25), (meth)acrylate (C26), (meth)acrylate (C27), (meth)acrylate (C28), (meth)acrylate (C29), (meth)acrylate (C30), (meth)acrylate (C31), (meth)acrylate (C32), (meth)acrylate (C33), (meth)acrylate (C34), (meth)acrylate (C35), (meth)acrylate (C36), (meth)acrylate (C37), (meth)acrylate (C38), (meth)acrylate (C39 ...9), (meth)acrylate (C39), (meth)acrylate (C39), (meth)acrylate (Meth)acrylic acid alkyl such as henoicosyl (C21) methacrylate and docosyl (meth)acrylate (C22); unsaturated ethylene monomers having an alkyl group such as 1-heptene, 3,3-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1-octene, 3,3-dimethyl-1-hexene, 3,4-dimethyl-1-hexene, 4,4-dimethyl-1-hexene, 1-nonene, 3,5,5-trimethyl-1-hexene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and 1-docosene. These may be used alone or in combination of two or more.

[0045] <<Polymerizable hydrophilic monomer>> The polymerizable hydrophilic monomer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polymerizable hydrophilic monomer include anionic unsaturated ethylene monomers such as maleic acid or a salt thereof, monomethyl maleate, itaconic acid, monomethyl itaconate, fumaric acid, 4-styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, or unsaturated ethylene monomers containing phosphoric acid, phosphonic acid, alendronic acid, or etidronic acid; and nonionic unsaturated ethylene monomers such as 2-hydroxyethyl (meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, (meth)acrylamide, N-methylol(meth)acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, acrylamide, N,N-dimethylacrylamide, Nt-butylacrylamide, N-octylacrylamide, and Nt-octylacrylamide.

[0046] The content of the structural units derived from the polymerizable hydrophobic monomer and the structural units derived from the polymerizable hydrophilic monomer is not particularly limited and can be appropriately selected depending on the purpose. For example, the content of the structural units derived from the monomers forming the copolymer, i.e., the structural units derived from the first monomer, the structural units derived from the second monomer, and the structural units derived from the third monomer, can be in the range of 5% by mass or more and 100% by mass or less.

[0047] <<Polymerizable surfactants>> The polymerizable surfactant is a surfactant having at least one radically polymerizable unsaturated double bond group in the molecule, and examples thereof include anionic surfactants and nonionic surfactants.

[0048] -Anionic surfactants- The anionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, ammonium sulfate base (-SO3-NH4 +), etc., hydrocarbon compounds having sulfate groups and allyl groups (-CH2-CH=CH2), ammonium sulfate groups (-SO3-NH4 + ), etc., which have a sulfate group and a methacryl group (-CO-C(CH3)=CH2), or an ammonium sulfate group (-SO3-NH4 + ) and aromatic hydrocarbon compounds having a sulfate group and a 1-propenyl group (-CH=CH2CH3). Specific examples of the anionic surfactants include, by trade name, ELEMINOL JS-20, RS-300 (all manufactured by Sanyo Chemical Industries, Ltd.), AQUALON KH-10, AQUALON KH-1025, AQUALON KH-05, AQUALON HS-10, AQUALON HS-1025, AQUALON BC-0515, AQUALON BC-10, AQUALON BC-1025, AQUALON BC-20, AQUALON BC-2020 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.).

[0049] -Nonionic surfactants- The nonionic surfactant is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include a hydrocarbon compound or an aromatic hydrocarbon compound having a 1-propenyl group (-CH=CH2CH3) and a polyoxyethylene group (-(C2H4O)nH), where "n" in the polyoxyethylene group is an integer of 2 or more. Specific examples of the nonionic surfactants include, by trade name, Aqualon RN-20, Aqualon RN-2025, Aqualon RN-30, Aqualon RN-50 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Latemul PD-104, Latemul PD-420, Latemul PD-430, Latemul PD-450 (all manufactured by Kao Corporation).

[0050] The content of the structural units derived from the polymerizable surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, the content of the structural units derived from the monomers forming the copolymer, i.e., the total amount of the structural units derived from the first monomer, the structural units derived from the second monomer, and the structural units derived from the third monomer, can be in the range of 0.1 mass % or more and 10 mass % or less.

[0051] In the synthesis of the copolymer of the present invention, a radical polymerization initiator may be used. The radical polymerization initiator is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyesters, cyano-based azobisisobutyronitrile, azobis(2-methylbutyronitrile), azobis(2,2'-isovaleronitrile), non-cyano-based dimethyl-2,2'-azobisisobutyrate, etc. Among these, organic peroxides and azo-based compounds are preferred, and azo-based compounds are more preferred, in terms of ease of molecular weight control and low decomposition temperature.

[0052] The content of the radical polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1% by mass or more and 10% by mass or less based on the total amount of polymerizable monomers. The "polymerizable monomer" refers to all monomers including the first monomer, the second monomer, the third monomer, and other monomers.

[0053] In order to adjust the molecular weight of the copolymer of the present invention, a chain transfer agent may be added. The chain transfer agent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, dodecyl mercaptan, 1-dodecanethiol, and thioglycerol.

[0054] The weight average molecular weight (Mw) of the copolymer of the present invention is preferably from 5,000 to 50,000, more preferably from 15,000 to 40,000, from the viewpoints of storage stability of the colorant dispersion and ink, and redispersibility of the ink.

[0055] The method for measuring the weight average molecular weight (Mw) of the copolymer is not particularly limited, but it can be measured, for example, by the following method. [An example of how to measure weight average molecular weight (Mw)] Measurement was performed by GPC (Gel Permeation Chromatography) under the following conditions. Equipment: GPC-8320GPC (Tosoh Corporation) Column: TSK G2000HXL and G4000HXL (Tosoh Corporation) ·Temperature: 40℃ Solvent: THF (tetrahydrofuran) Flow rate: 0.6mL / min 1 mL of a polymer with a concentration of 0.5% by mass is injected into the apparatus, and the weight average molecular weight Mw of the copolymer is calculated from the molecular weight distribution of the copolymer measured under the above conditions using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

[0056] The structure of the copolymer in the present invention is not particularly limited and can be appropriately selected depending on the purpose. Examples of the copolymer include random copolymers, graft copolymers, and block copolymers.

[0057] The polymerization temperature for forming the copolymer in the present invention is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 50°C to 150°C, more preferably 60°C to 100°C. The polymerization time for forming the copolymer in the present invention is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 3 to 48 hours.

[0058] The method for synthesizing the copolymer of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, radical polymerization can be mentioned.

[0059] (ink) The ink of the present invention contains water, a coloring material, and a copolymer, and may contain other components as necessary. Here, the "copolymer" is the same as that described in the above (copolymer) section, so duplicate descriptions will be omitted.

[0060] <Water> The water contained in the ink is not particularly limited and can be appropriately selected depending on the purpose. The water content is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, the water content is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass to 60% by mass, of the total amount of the ink.

[0061] <Coloring material> The coloring material contained in the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose, and for example, pigments, dyes, etc. can be used. Mixed crystals can also be used.

[0062] <<Pigments>> The pigment is not particularly limited and can be appropriately selected depending on the purpose. For example, black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, metallic pigments, and the like can be used. Examples of the white pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, and aluminum hydroxide.

[0063] As the pigment, inorganic pigments and organic pigments can be used. The inorganic pigment is not particularly limited and can be appropriately selected depending on the purpose. Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon black produced by a known method such as a contact method, a furnace method, or a thermal method. The organic pigment is not particularly limited and can be appropriately selected depending on the purpose. Examples of the organic pigment include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye-type chelates, acid dye-type chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

[0064] Specific examples of the pigment include the following: Examples of black pigments include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper and iron (CI Pigment Black 11); and organic pigments such as aniline black (CI Pigment Black 1). Examples of white pigments include titanium oxide, titanium dioxide, and hollow resin particles. Color pigments include CI Pigment Yellow 1, CI Pigment Yellow 3, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 17, CI Pigment Yellow 24, CI Pigment Yellow 34, CI Pigment Yellow 35, CI Pigment Yellow 37, CI Pigment Yellow 42 (Yellow Iron Oxide), CI Pigment Yellow 53, CI Pigment Yellow 55, CI Pigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow 76, CI Pigment Yellow 77, CI Pigment Yellow 78, CI Pigment Yellow 79, CI Pigment Yellow 80, CI Pigment Yellow 81, CI Pigment Yellow 82, CI Pigment Yellow 83, CI Pigment Yellow 84, CI Pigment Yellow 85, CI Pigment Yellow 86, CI Pigment Yellow 87, CI Pigment Yellow 88, CI Pigment Yellow 89, CI Pigment Yellow 90, CI Pigment Yellow 91, CI Pigment Yellow 92, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 95, CI Pigment Yellow 96, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Yellow 99, CI Pigment Yellow 100, CI Pigment Yellow 101, CI Pigment Yellow 102, CI Pigment Yellow 103, CI Pigment Yellow 104, CI Pigment Yellow 105, CI Pigment Yellow 106, CI Pigment Yellow 107, CI Pigment Yellow 108, CI Pigment Yellow 109, -81, CI Pigment Yellow 83, CI Pigment Yellow 95, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Yellow 100, CI Pigment Yellow 101, CI Pigment Yellow 104, CI Pigment Yellow 108, CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 117, CI Pigment Yellow 120, CI Pigment Yellow 138, CI Pigment Yellow 150, CI Pigment Yellow 153, CI Pigment Yellow 155, CI Pigment Yellow 180, CI Pigment Yellow 185, CI Pigment Yellow 213, CI Pigment Orange 5, CI Pigment Orange 13, CI Pigment Orange 16, CI Pigment Orange 17, CI Pigment Orange 36, CI Pigment Orange 43, CI Pigment Orange 51, CI Pigment Red 1, CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 5, CI Pigment Red 17 , CI Pigment Red 22, CI Pigment Red 23, CI Pigment Red 31, CI Pigment Red 38, CI Pigment Red 48:2 (Permanent Red 2B (Ca)), CI Pigment Red 48:3, CI Pigment Red 48:4, CI Pigment Red 49:1, CI Pigment Red 52:2, CI Pigment Red 53:1, CI Pigment Red 57:1 (Brilliant Carmine 6B), CI Pigment Red 60:1, CI Pigment Red 63:1, C.I. Pigment Red 63:2, CI Pigment Red 64:1, CI Pigment Red 81, CI Pigment Red 83, CI Pigment Red 88, CI Pigment Red 101 (Red Flax), CI Pigment Red 104, CI Pigment Red 105, CI Pigment Red 106, CI Pigment Red 108 (Cadmium Red), CI Pigment Red 112, CI Pigment Red 114, CI Pigment Red 122 (Quinacridone Magenta), CI Pigment Red 1 23, CI Pigment Red 146, CI Pigment Red 149, CI Pigment Red 166, CI Pigment Red 168, CI Pigment Red 170, CI Pigment Red 172, CI Pigment Red 177, CI Pigment Red 178, CI Pigment Red 179, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 190, CI Pigment Red 193, CI Pigment Red 202, CI Pigment Red 207, CI Pigment Red 208, CI Pigment Red 209, CI Pigment Red 213, CI Pigment Red 219, CI Pigment Red 224, CI Pigment Red 254, CI Pigment Red 264, CI Pigment Violet 1 (Rhodamine Lake), CI Pigment Violet 3, CI Pigment Violet 5:1, CI Pigment Violet 16, CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Violet 38, CI Pigment Blue Rue 1, CI Pigment Blue 2, CI Pigment Blue 15 (Phthalocyanine Blue), CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4 (Phthalocyanine Blue), CI Pigment Blue 16, CI Pigment Blue 17:1, CI Pigment Blue 56, CI Pigment Blue 60, CI Pigment Blue 63, CI Pigment Green 1, CI Pigment Green 4, CI Pigment Green 7, CIPigment Green 8, CI Pigment Green 10, CI Pigment Green 17, CI Pigment Green 18, CI Pigment Green 36, etc.

[0065] <<dye>> The dye is not particularly limited and may be appropriately selected depending on the purpose. For example, acid dyes, direct dyes, reactive dyes, and basic dyes may be used. These may be used alone or in combination of two or more.

[0066] Specific examples of the dyes include CI Acid Yellow 17, CI Acid Yellow 23, CI Acid Yellow 42, CI Acid Yellow 44, CI Acid Yellow 79, CI Acid Yellow 142, CI Acid Red 52, CI Acid Red 80, CI Acid Red 82, CI Acid Red 249, CI Acid Red 254, CI Acid Red 289, CI Acid Blue 9, CI Acid Blue 45, CI Acid Blue 249, CI Acid Black 1, CI Acid Black 2, CI Acid Black 24, CI Acid Black 94, CI Food Black 1, CI Food Black 2, CI Direct Yellow 1, CI Direct Yellow 12, CI Direct Yellow 24, CI Direct Yellow 33, CI Direct Yellow 50, CI Direct Yellow 55, CI Direct Yellow 58, CI Direct Yellow 86, CI Direct Yellow 132, CI Direct Yellow 142, CI Direct Yellow 144, CI Dye Direct Yellow 173, CI Direct Red 1, CI Direct Red 4, CI Direct Red 9, CI Direct Red 80, CI Direct Red 81, CI Direct Red 225, CI Direct Red 227, CI Direct Blue 1, CI Direct Blue 2, CI Direct Blue 15, CI Direct Blue 71, CI Direct Blue 86, CI Direct Blue 87, CI Direct Blue 98, CI Direct Blue 165, CI Direct Blue 199, CI Direct Blue 202, CI Directed Black 19, CI Directed Black 38, CI Directed Black 51, CI Directed Black 71, CI Directed Black 154, CI Directed Black 168, CI Directed Black 171, CI Directed Black 195, CI Reactive Red 14, CI Reactive Red 32, CI Reactive Red 55, CI Reactive Red 79, CI Reactive Red 249, CI Reactive Black 3, CIReactive Black 4, CI Reactive Black 35, etc.

[0067] As the coloring material in the present invention, a pigment is preferred from the viewpoints of excellent adsorption ability to the copolymer, and excellent water resistance and weather resistance. In particular, when a white pigment is used as the coloring material, titanium oxide and barium sulfate are preferred from the viewpoint of excellent white hiding power, titanium oxide is more preferred, and titanium oxide is preferred from the viewpoints of excellent storage stability of the coloring material dispersion, storage stability of the ink, and redispersibility of the ink.

[0068] The content of the colorant contained in the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of improving image density and obtaining good fixability and ejection stability, however, the content is preferably from 0.1% by mass to 15% by mass, and more preferably from 10% by mass to 15% by mass, based on the total amount of the ink.

[0069] <Other ingredients> The other components are not particularly limited and can be appropriately selected depending on the purpose. Examples of the other components include other resins (A), organic solvents, additives, radical polymerization initiators, and chain transfer agents.

[0070] <<Other resins (A)>> The ink of the present invention may contain another resin (A) different from the copolymer. The other resin (A) is not particularly limited and can be appropriately selected depending on the purpose. Examples of the other resin (A) include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. These may be used alone or in combination of two or more.

[0071] Resin particles made of the other resin (A) may be used as the other resin. The resin particles to be used may be appropriately synthesized or commercially available products.

[0072] The volume average particle size of the resin particles is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of obtaining good fixing property and high image hardness, the volume average particle size is preferably 10 nm or more and 1000 nm or less, more preferably 10 nm or more and 200 nm or less, and particularly preferably 10 nm or more and 100 nm or less. The volume average particle size of the resin particles can be measured, for example, using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac-Bell Co., Ltd.).

[0073] <<Organic solvents>> The ink of the present invention may contain an organic solvent. Since the copolymer is water-soluble in the ink, it may be used in combination with a hydrophilic organic solvent. The organic solvent is not particularly limited and can be appropriately selected depending on the purpose. For example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, polyhydric alcohols such as 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethyl ... Examples of the alkyl ethers include polyhydric alcohols such as ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; polyhydric alcohols such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone; amides such as formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine, and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol; propylene carbonate, and ethylene carbonate.

[0074] When the organic solvent is used as the penetrant, it is preferable to use triethylene glycol monobutyl ether as the penetrant. By including triethylene glycol monobutyl ether in the ink, when printing on a fabric as a recording medium described later, the penetrability into the fabric can be adjusted to an appropriate level, and the problem of the ink penetrating too much into the fabric and failing to obtain a good image can be solved, which is preferable.

[0075] When the organic solvent is used as a moisturizing agent, it is preferable to use ethylene glycol and glycerin as the moisturizing agent. The ethylene glycol is relatively inexpensive and has high moisturizing properties, and can improve the ejection properties of the ink. Furthermore, when a dispersant with high hydrophilicity is used, the storage stability of the ink can be improved. The glycerin has a higher boiling point than other organic solvents, and can improve the ejection stability of the ink.

[0076] The organic solvent not only functions as a wetting agent but also has good drying properties, so it is preferable to use an organic solvent having a boiling point of 250° C. or less.

[0077] When paper is used as the recording medium, polyol compounds having 8 or more carbon atoms and glycol ether compounds can be suitably used as the organic solvent from the viewpoint of improving the permeability of the ink. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

[0078] The content of the organic solvent is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, the content is preferably from 10% by mass to 60% by mass, more preferably from 20% by mass to 70% by mass, and even more preferably from 45% by mass to 65% by mass.

[0079] <<Additives>> The additives are not particularly limited and may be appropriately selected depending on the purpose. Examples of the additives include surfactants, antifoaming agents, antiseptic and antifungal agents, rust inhibitors, and pH adjusters that are used as other components.

[0080] -Surfactants used as other ingredients- The surfactant used as the other component is not particularly limited and can be appropriately selected depending on the purpose. Examples of the surfactant include silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants. In this specification, the term "surfactant used as another component" refers to a surfactant contained in the ink of the present invention as another component, and does not fall under the above-mentioned <other polymerizable monomers>.

[0081] --Silicone surfactants-- The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the silicone surfactant does not decompose even at high pH (pH 11 to 14). Specific examples of silicone surfactants that do not decompose even at high pH (pH 11 to 14) include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, side-chain both-end modified polydimethylsiloxane, etc. Among these, polyether-modified silicone surfactants having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group are preferred from the viewpoint of improving hydrophilicity and increasing solubility in water. These may be used alone or in combination of two or more.

[0082] The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be one in which a polyalkylene oxide structure represented by the general formula (S-1) is introduced into the Si part side chain of dimethylpolysiloxane.

[0083] [ka] (In the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)

[0084] The polyether-modified silicone surfactant may be appropriately synthesized or may be a commercially available product. Examples of commercially available polyether-modified silicone surfactants include KF-618, KF-642, KF-643 (all manufactured by Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, EMALEX-SS-1906EX (all manufactured by Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (all manufactured by Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (all manufactured by Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (all manufactured by Toshiba Silicon Co., Ltd.), etc.

[0085] The silicone surfactant may be a synthetic product or a commercially available product, such as those available from BYK Chemical Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., etc.

[0086] --Fluorosurfactant-- The fluorosurfactant is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a compound having 2 to 16 fluorine-substituted carbon atoms, and more preferably a compound having 4 to 16 fluorine-substituted carbon atoms.

[0087] The fluorosurfactant is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of low foaming, however, perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferred. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonate salts. Examples of the perfluoroalkyl carboxylic acid compound include perfluoroalkyl carboxylic acids and perfluoroalkyl carboxylates. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group on the side chain include sulfate ester salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group on the side chain, and salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group on the side chain.

[0088] As the fluorosurfactant, fluorosurfactants represented by the following general formulas (F-1) and (F-2) are more preferable.

[0089] [ka] In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40 in order to impart water solubility.

[0090] [ka] In the compound represented by the general formula (F-2), Y is H or C m F 2m+1 (m is an integer from 1 to 6), or CH2CH(OH)CH2-C m F 2m+1 (m is an integer from 4 to 6), or C p H2p+1 (p is an integer from 1 to 19), n is an integer from 1 to 6, and a is an integer from 4 to 14.

[0091] Counter ions of the salts in these fluorosurfactants include Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, NH(CH2CH2OH)3, and the like.

[0092] The fluorosurfactant may be a synthetic product or a commercially available product. Examples of commercially available fluorosurfactants include Surflon S-111, Surflon S-112, Surflon S-113, Surflon S-121, Surflon S-131, Surflon S-132, Surflon S-141, Surflon S-145 (all manufactured by AGC Inc.), Fullard FC-93, Fullard FC-95, Fullard FC-98, Fullard FC-129, Fullard FC-135, Fullard FC-170C, Fullard FC-430, Fullard FC-431 (all manufactured by Sumitomo 3M Limited), Megafac F-470, Megafac F-1405, Megafac F-474 (all manufactured by DIC Corporation), Zonyl TB, etc. S, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, Capstone FS-31, Capstone FS-3100, Capstone FS-34, Capstone FS-35 (all manufactured by Chemours), FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, Polyfox PF-156A, Polyfox PF-151N, Polyfox PF-154, Polyfox PF-159 (all manufactured by Omnova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc. Among these, FS-3100, FS-34, FS-300 (all manufactured by Chemours), FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-151N (all manufactured by Omnova), and Unidyne DSN-403N (all manufactured by Daikin Industries, Ltd.) are preferred because they provide good print quality, particularly improved color development, penetration into paper, wettability, and dye uniformity.

[0093] --Amphoteric surfactants-- The amphoteric surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine. These may be used alone or in combination of two or more.

[0094] --Nonionic surfactants-- The nonionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the nonionic surfactant include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohol. These may be used alone or in combination of two or more.

[0095] --Anionic surfactants-- The anionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the anionic surfactant include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and polyoxyethylene alkyl ether sulfates. These may be used alone or in combination of two or more.

[0096] The content of the surfactant used as another component is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of excellent wettability and ejection stability and improved image quality, the content is preferably from 0.001% by mass to 5% by mass, and more preferably from 0.05% by mass to 5% by mass, relative to the total amount of the ink.

[0097] - Defoaming agent - The surfactant used as the other component can be used as a defoaming agent. The defoaming agent is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include silicone-based defoaming agents, polyether-based defoaming agents, fatty acid ester-based defoaming agents, etc. Among these, silicone-based defoaming agents are preferred because of their excellent foam breaking effect. These may be used alone or in combination of two or more.

[0098] -Preservative and fungicide- The antiseptic and antifungal agent is not particularly limited and can be appropriately selected depending on the purpose. For example, 1,2-benzisothiazolin-3-one and the like can be mentioned.

[0099] -pH adjuster- The pH adjuster is not particularly limited and may be appropriately selected depending on the purpose as long as it can adjust the pH to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine. Among these, triethanolamine, which is inexpensive, is preferable. The content of the pH adjuster is preferably 0.5% by mass or less based on the total amount of the ink, and more preferably 0.25% by mass or more and 0.5% by mass or less from the viewpoint of storage stability of the ink.

[0100] [Ink properties] The physical properties of the ink of the present invention are not particularly limited and can be appropriately set depending on the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc. are within the following ranges.

[0101] The viscosity of the ink of the present invention at 25°C is preferably from 5 mPa·s to 30 mPa·s, more preferably from 5 mPa·s to 25 mPa·s, in order to improve print density and character quality and to obtain good ejection properties. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). The viscosity can be measured under the following conditions: 25°C, standard cone rotor (1°34'×R24), sample liquid volume of 1.2 mL, rotation speed of 50 rpm, and 3 minutes.

[0102] The surface tension of the ink of the present invention is preferably 35 mN / m or less, and more preferably 32 mN / m or less at 25° C., from the viewpoints of suitably leveling the ink on a recording medium described below and shortening the drying time of the ink.

[0103] The pH of the ink of the present invention is preferably from 7 to 12, and more preferably from 8 to 11, from the viewpoint of preventing corrosion of metal members that come into contact with the ink.

[0104] Methods for qualitatively and quantitatively determining the organic solvent, copolymer, pigment, and other components contained in the ink of the present invention include, for example, gas chromatography mass spectrometry (GC-MS). An example of a measuring device using gas chromatography mass spectrometry (GC-MS) is GCMS-QP2020NX (manufactured by Shimadzu Corporation). The amount of water contained in the ink can be measured by a general method such as quantifying the volatile components using gas chromatography mass spectrometry (GC-MS) or measuring mass fluctuations using thermogravimetry-differential thermal analysis (TG-DTA).

[0105] (ink container) The ink of the present invention can be used by being contained in a container. In this specification, a container that contains the ink of the present invention is sometimes referred to as an "ink containing container." The ink container is not particularly limited, and examples thereof include known ink cartridges for inkjet printers. The ink storage container is easy to store, transport, and the like, and has excellent handleability, and therefore can be detachably attached to an ink cartridge, an image forming apparatus, and the like, and used to replenish ink. The ink container is not particularly limited and can be appropriately selected from known containers, and examples thereof include a container having a container body and a cap.

[0106] The shape of the ink container is not particularly limited and may be appropriately selected depending on the purpose, but is preferably cylindrical. Furthermore, it is preferable that the inner peripheral surface is formed with a spiral irregularity so that the ink contained therein can move to the outlet side by rotating the container, and that a part or all of the spiral irregularity has a bellows function. The material of the ink container is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of good dimensional accuracy, however, resins such as polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacrylic acid, polycarbonate resin component ABS resin, and polyacetal resin are preferred. The structure and size of the ink container are not particularly limited and can be appropriately selected according to the purpose.

[0107] (Image forming apparatus and image forming method) The image forming apparatus of the present invention comprises an ink containing container that contains the ink of the present invention, and an ejection means that ejects the ink contained in the ink containing container onto a recording medium, and may also have other means as necessary. The image forming method of the present invention comprises a step of ejecting the ink of the present invention onto a recording medium to form an image, and may also comprise other steps as necessary. The image forming method can be suitably carried out by the image forming apparatus.

[0108] <Discharge Means and Discharge Process> The ejection means is a means for ejecting the ink contained in the ink container onto a recording medium. The ejection step is a step of ejecting the ink contained in the ink container onto a recording medium. The ejection step can be suitably carried out by the ejection means. The ejection means is not particularly limited, and any known ink ejection means can be used, such as an inkjet system.

[0109] <Other means and other steps> The other means are not particularly limited and can be appropriately selected depending on the purpose. Examples of the other means include pre-treatment means, post-treatment means, heating means, drying means, and means related to feeding, transporting, and discharging of the recording medium. The other steps are not particularly limited and can be appropriately selected depending on the purpose. Examples of the other steps include a pre-treatment step, a post-treatment step, a heating step, a drying step, and steps related to feeding, transporting, and discharging a recording medium. The other steps can be suitably carried out by the other means.

[0110] -Pretreatment means and pretreatment process- The pretreatment unit is a unit that applies a pretreatment liquid to the recording medium before applying the ink. The pretreatment step is a step of applying a pretreatment liquid to the recording medium before applying the ink. The pretreatment step can be suitably carried out by the pretreatment means. One aspect of a pretreatment device equipped with the pretreatment means is to add a liquid storage section having the pretreatment liquid and a liquid ejection head, as in the case of inks such as black (K), cyan (C), magenta (M), yellow (Y), and white (W), and to eject the pretreatment liquid by an inkjet recording method. The pretreatment means is not particularly limited and can be appropriately selected depending on the purpose. Examples of the pretreatment means include a means in which the pretreatment liquid is stored in an ink storage means like a normal ink and applied to a recording medium by an inkjet method, a blade coating method, a roll coating method, a spray coating method, and the like.

[0111] The pretreatment liquid contains a flocculant, an organic solvent, and water, and may contain, as necessary, a surfactant, an antifoaming agent, a pH adjuster, an antiseptic / fungal agent, an antirust agent, and the like. The organic solvent, the surfactant, the defoaming agent, the pH adjuster, the preservative and antifungal agent, and the rust inhibitor can be similar to the materials used in the ink, and other materials used in known treatment liquids can be used. The type of the flocculant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the flocculant include water-soluble cationic polymers, acids, and polyvalent metal salts.

[0112] -Post-processing means and post-processing process- The post-treatment unit is a unit that applies a post-treatment liquid to the recording medium after applying the ink. The pretreatment step is a step of applying a posttreatment liquid to the recording medium after applying the ink. The post-treatment step can be suitably carried out by the post-treatment means. One aspect of a post-processing device equipped with the post-processing means is to add a liquid storage section having the post-processing liquid and a liquid ejection head, as in the case of inks such as black (K), cyan (C), magenta (M), yellow (Y), and white (W), and to eject the post-processing liquid by an inkjet recording method. The post-treatment means is not particularly limited and can be appropriately selected depending on the purpose. Examples of the post-treatment means include a means in which the post-treatment liquid is stored in an ink storage means like a normal ink and applied to a recording medium by an inkjet method, a blade coating method, a roll coating method, a spray coating method, and the like.

[0113] The post-treatment liquid is not particularly limited as long as it can form a transparent layer. The post-treatment liquid is obtained by selecting and mixing organic solvents, water, resins, surfactants, defoamers, pH adjusters, antiseptics, antifungals, rust inhibitors, etc. as necessary. The post-treatment liquid may be applied to the entire recording area formed on the recording medium, or may be applied only to the area where an image is formed.

[0114] -Heating means and heating process, and drying means and drying process- The heating means includes, for example, a means for heating the print surface or the back surface of the recording medium. The heating step includes, for example, a step of heating the print surface and the back surface of the recording medium. The heating step can be suitably carried out by the heating means. The drying means includes, for example, a means for drying the printed surface and the back surface of the recording medium. The drying step includes, for example, a step of drying the printed surface and the back surface of the recording medium. The drying step can be suitably carried out by the drying means. The heating means and drying means are not particularly limited, and for example, a hot air heater, an infrared heater, etc. Heating and drying can be carried out before, during, or after printing.

[0115] The image forming apparatus and the image forming method are not limited to those that visualize meaningful images such as characters and figures with ink. For example, they also include those that form patterns such as geometric patterns and those that create three-dimensional images. Unless otherwise specified, the image forming apparatus includes both a serial type apparatus in which the ejection head is moved and a line type apparatus in which the ejection head is not moved. The image forming device includes not only desktop types, but also wide recording devices capable of printing on A0 size recording media, and continuous feed printers that can use continuous paper wound into a roll as a recording medium.

[0116] <Recording Media> In this specification, the term "recording medium" refers to an object on which recording is performed using the ink of the present invention. The recording medium also refers to anything to which the ink of the present invention or various treatment liquids can be attached, even if only temporarily. The recording medium is not particularly limited and can be appropriately selected depending on the purpose. For example, plain paper, glossy paper, special paper, cloth, film, OHP sheet, general-purpose printing paper, non-permeable substrate, etc. may be used. The non-permeable substrate is a substrate having a surface with low water permeability and low absorbency, and includes materials that have many cavities inside but are not open to the outside. More quantitatively, in the Bristow method, 1 / 2 Water absorption up to 10mL / m 2 The term "substrate" refers to a substrate that is: Examples of the non-permeable substrate include plastic films such as polyvinyl chloride resin films, polyethylene terephthalate (PET) films, polypropylene, polyethylene, and polycarbonate films.

[0117] The recording medium is not limited to those generally used as recording media, and may be appropriately used wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather, etc. Also, by adjusting the configuration of the path for conveying the recording medium, ceramics, glass, metal, etc. may be used.

[0118] <Recordings> An image formed on the recording medium using the ink of the present invention can be considered as a recorded matter. The recorded matter can be obtained by recording using the image forming apparatus and image forming method.

[0119] Here, an example of an image forming apparatus of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing an example of an image forming apparatus of the present invention. Figure 2 is a schematic diagram showing an example of an ink cartridge. The image forming apparatus 400 is a serial type image forming apparatus. A mechanism unit 420 is provided inside an exterior 401 of the image forming apparatus 400. Each ink storage unit 411 of the main tanks 410 (410k, 410c, 410m, 410y, 410w) for each color of black (K), cyan (C), magenta (M), yellow (Y), and white (W) is formed of a packaging material such as an aluminum laminate film. The ink storage unit 411 is stored in a storage container case 414 made of, for example, plastic. As a result, the main tanks 410 are used as ink cartridges for each color. On the other hand, a cartridge holder 404 is provided at the back side of the opening when the cover 401c of the apparatus body is opened. A main tank 410 is detachably attached to the cartridge holder 404. This allows each ink outlet 413 of the main tank 410 to communicate with an ejection head 434 for each color via a supply tube 436 for each color, making it possible to eject ink from the ejection head 434 to a recording medium.

[0120] <Application> The ink of the present invention can be suitably used in various recording devices using the ink jet recording method, such as printers, facsimile machines, copying machines, printer / fax / copier combination machines, and three-dimensional modeling devices. The application of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose, and can be applied to, for example, printed matter, paint, coating material, base, etc. Furthermore, it can be used not only to form two-dimensional characters and images, but also as a material for three-dimensional modeling to form three-dimensional solid images (three-dimensional objects). The three-dimensional object includes a three-dimensional object obtained by applying ink in layers, etc. Also included is a molded product obtained by processing a structure in which ink is applied onto a substrate such as a recording medium. The three-dimensional modeling device for forming the three-dimensional object can be a known one, and is not particularly limited, but can be, for example, one equipped with ink storage means, supply means, ejection means, drying means, etc. The molded products are, for example, products obtained by subjecting recorded matter or structures formed into a sheet or film shape to molding processes such as heat stretching or punching, and are suitably used for applications in which the surface is molded after decoration, such as meters and operation panel for automobiles, office automation equipment, electric and electronic equipment, cameras, etc.

[0121] (Solar cell backsheet) The copolymer can also be used as a resin contained in a protective layer of a solar cell back sheet. In other words, the solar cell backsheet of the present invention is a solar cell backsheet having a protective layer, and the protective layer is a coating film made of ink, and may contain other resin (B) as necessary. Note that the "ink" is the same as that described in the above item (ink), and therefore the duplicated description will be omitted. The solar cell backsheet of the present invention can improve weather resistance against light irradiation from the light-receiving surface side and the back surface side of the solar cell module, for example, by providing it on the back surface of the solar cell module.

[0122] The protective layer is preferably provided on a substrate film. The substrate film is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a polyester film from the viewpoint of excellent mechanical strength, dimensional stability, and thermal stability, and more preferably a polyester film mainly composed of polyethylene terephthalate or polyethylene naphthalate.

[0123] The protective layer in the solar cell module may contain another resin (B). The other resin (B) is not particularly limited and may be appropriately selected depending on the purpose, but from the viewpoint of excellent mechanical strength and heat resistance, an acrylic resin is preferable, and an acrylic resin capable of being crosslinked with an isocyanate is more preferable.

[0124] The method for producing the solar cell backsheet is not particularly limited and can be appropriately selected depending on the purpose. For example, the solar cell backsheet can be produced by the following method (steps (1) to (4)). Step (1): The copolymer of the present invention is added to an organic solvent, and the solution is prepared by stirring and dissolving the copolymer. If necessary, a coloring material is gradually added to the solution while stirring the solution, and the solution is stirred again. Step (2): After dispersing using a dispersing device, the contents are filtered through a membrane filter. If necessary, an adjusted amount of an organic solvent is added to prepare a protective layer forming liquid. Step (3): The protective layer forming liquid is applied to the surface of the substrate using a wire bar and dried until a desired thickness is reached, to form a protective layer (coating film). Step (4): The protective layer is aged to obtain a solar cell backsheet.

[0125] The organic solvent in the step (1) is not particularly limited and can be appropriately selected depending on the purpose. For example, the organic solvents described in the above (Ink) section and hexamethylene diisocyanate can be suitably used. The coloring material in the step (1) is not particularly limited and can be appropriately selected depending on the purpose. For example, the coloring materials described in the above (ink) section can be suitably used. The dispersing device in the step (2) is not particularly limited and can be appropriately selected depending on the purpose, for example, Big Rotor BR-2 (manufactured by AS ONE Corporation), etc. The conditions for the dispersion treatment are not particularly limited and can be appropriately selected depending on the purpose, for example, the rotation speed can be set to 90 rpm and the treatment time can be set to 5 days, etc. The substrate in step (3) is not particularly limited and can be appropriately selected depending on the purpose. For example, the recording media described in the above section (Image forming apparatus and image forming method) can be suitably used. The "any film thickness" in the step (3) is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, 2 μm. The drying conditions in the step (3) are not particularly limited and can be appropriately selected depending on the purpose. For example, the drying temperature can be set to 150° C. and the drying time can be set to 5 minutes. The aging conditions in the step (4) are not particularly limited and can be appropriately selected depending on the purpose. For example, the treatment temperature can be set to 50° C. and the treatment time can be set to 3 days.

[0126] In this specification, the terms image formation, recording, printing, printing, etc. are all synonymous. In this specification, the terms recording medium, media, and printed matter are all synonymous. EXAMPLES

[0127] Examples of the present invention will be described below, but the scope of the present invention is not limited to these examples. In the following examples and comparative examples, "parts" and "%" are "parts by mass" and "% by mass" unless otherwise specified.

[0128] The molecular weights of the copolymers obtained in the Synthesis Examples, Examples, and Comparative Examples described below were measured by the following method and conditions. [Method for measuring weight average molecular weight] Measurement was performed by GPC (Gel Permeation Chromatography) under the following conditions. Equipment: GPC-8320GPC (Tosoh Corporation) Column: TSK G2000HXL and G4000HXL (Tosoh Corporation) ·Temperature: 40℃ Solvent: THF (tetrahydrofuran) Flow rate: 0.6mL / min 1 mL of the copolymer having a concentration of 0.5% by mass was injected into the above apparatus, and the weight-average molecular weight Mw of the copolymer was calculated from the molecular weight distribution of the copolymer measured under the above conditions using a molecular weight calibration curve prepared from monodisperse polystyrene standard samples.

[0129] (Synthesis Example 1) <Synthesis of Monomer M-9> 11.77g (120mmol) of concentrated sulfuric acid (manufactured by Kokusan Chemical Co., Ltd.) was added little by little to 31.03g (500mmol) of ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) and heated to 50°C. 12.31g (100mmol) of isonicotinic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added little by little with stirring, heated to 120°C and stirred for 5 hours. After cooling to room temperature, 4N aqueous sodium hydroxide solution (manufactured by Kanto Chemical Co., Ltd.) was added with stirring until the pH became 7. Extraction was performed twice with 150ml of ethyl acetate (manufactured by Kanto Chemical Co., Ltd.), and the isolated organic phase was washed twice with 150ml of water, and then the isolated organic phase was dried with magnesium sulfate (manufactured by Kanto Chemical Co., Ltd.). The solvent was distilled off from the organic phase, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane (manufactured by Kanto Chemical Co., Ltd.) / ethyl acetate (manufactured by Kanto Chemical Co., Ltd.) (volume ratio 5 / 5 to 0 / 10) as an eluent to obtain 9.55 g of intermediate 1.

[0130] [ka]

[0131] Next, 8.36 g (50 mmol) of intermediate 1 was dissolved in 20 mL of dehydrated tetrahydrofuran (THF) (Kanto Chemical Co., Ltd.). A solution of 9.31 g (60 mmol) of 2-isocyanate ethyl methacrylate (Tokyo Chemical Industry Co., Ltd.) dissolved in 10 mL of dehydrated THF was added dropwise to this solution over 10 minutes, and then stirred at 35 ° C. for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 11.55 g of monomer M-9.

[0132] [ka]

[0133] (Synthesis Example 2) <Synthesis of Monomer M-10> 59.08g (500mmol) of 1,6-hexanediol (Tokyo Chemical Industry Co., Ltd.) was heated to 80°C, 11.77g (120mmol) of concentrated sulfuric acid was added in small portions, and then 12.31g (100mmol) of isonicotinic acid was added in small portions with stirring, and the mixture was heated to 120°C and stirred for 5 hours. After cooling to room temperature, 4N aqueous sodium hydroxide solution was added with stirring until the pH reached 7. Extraction was performed twice with 200ml of ethyl acetate, and the isolated organic phase was washed twice with 200ml of water, and then the isolated organic phase was dried over magnesium sulfate. The solvent was distilled off from the organic phase, and the residue was purified by column chromatography on silica gel using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent to obtain 13.67g of intermediate 2.

[0134] [ka]

[0135] Next, 11.16 g (50 mmol) of intermediate 2 was dissolved in 20 mL of dehydrated THF. To this solution, a solution in which 9.31 g (60 mmol) of 2-isocyanate ethyl methacrylate was dissolved in 10 mL of dehydrated THF was dropped over 10 minutes, and then the mixture was stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 13.34 g of monomer M-10.

[0136] [ka]

[0137] (Synthesis Example 3) <Synthesis of Monomer M-11> 11.16 g (50 mmol) of intermediate 2 was dissolved in 20 mL of dehydrated THF. To this solution, 12.68 g (60 mmol) of methacrylic acid 6-isocyanate hexyl ester (manufactured by Hong Kong Chemhere Co., Ltd.) dissolved in 10 mL of dehydrated THF was dropped over 10 minutes, and then stirred at 35 ° C for 12 hours. The solvent was distilled off from the obtained reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 13.34 g of monomer M-11.

[0138] [ka]

[0139] (Synthesis Example 4) <Synthesis of Monomer M-12> 11.16g (50mmol) of intermediate 2 was dissolved in 20mL of dehydrated THF. To this solution, 16.05g (60mmol) of methacrylic acid (3-methyl-7,7-dimethyl-7-isocyanate) hexyl ester (manufactured by Hong Kong Chemhere Co., Ltd.) dissolved in 10mL of dehydrated THF was dropped over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 17.47g of monomer M-12.

[0140] [ka]

[0141] (Synthesis Example 5) <Synthesis of Monomer M-13> 87.14g (500mmol) of 1,10-decanediol (Tokyo Chemical Industry Co., Ltd.) was heated to 80°C, 11.77g (120mmol) of concentrated sulfuric acid was added in small portions, and then 12.31g (100mmol) of isonicotinic acid was added in small portions with stirring, and the mixture was heated to 120°C and stirred for 5 hours. After cooling to room temperature, 4N aqueous sodium hydroxide solution was added with stirring until the pH reached 7. Extraction was performed twice with 200ml of ethyl acetate, and the isolated organic phase was washed twice with 200ml of water, and then the isolated organic phase was dried over magnesium sulfate. The solvent was distilled off from the organic phase, and the residue was purified by column chromatography on silica gel using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent to obtain 14.55g of intermediate 3.

[0142] [ka]

[0143] Next, 13.97 g (50 mmol) of intermediate 3 was dissolved in 20 mL of dehydrated THF. To this solution, 16.05 g (60 mmol) of methacrylic acid (3-methyl-7,7-dimethyl-7-isocyanate) hexyl ester (manufactured by Hong Kong Chemhere Co., Ltd.) dissolved in 10 mL of dehydrated THF was dropped over 10 minutes, and then stirred at 35 ° C for 12 hours. The solvent was distilled off from the obtained reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 16.23 g of monomer M-13.

[0144] [ka]

[0145] (Synthesis Example 6) <Synthesis of Monomer M-14> 9.51 g (100 mmol) of 4-hydroxypyridine, 21.73 g (120 mmol) of 6-bromo-1-hexanol (Tokyo Chemical Industry Co., Ltd.), and 27.64 g (200 mmol) of potassium carbonate (Kanto Chemical Co., Ltd.) were added to 50 mL of methyl ethyl ketone (Kanto Chemical Co., Ltd.), and the mixture was refluxed for 18 hours. After cooling to room temperature, the mixture was filtered, and the solvent was distilled off from the filtrate. The residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, and 15.12 g of intermediate 4 was obtained.

[0146] [ka]

[0147] Next, 9.77 g (50 mmol) of intermediate 4 was dissolved in 20 mL of dehydrated THF. To this solution, a solution of 8.47 g (60 mmol) of acrylic acid 2-isocyanate ethyl ester (Tokyo Chemical Industry Co., Ltd.) dissolved in 10 mL of dehydrated THF was dropped over 10 minutes, and then stirred at 35 ° C for 12 hours. The solvent was distilled off from the obtained reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 14.38 g of monomer M-14.

[0148] [ka]

[0149] (Synthesis Example 7) <Synthesis of Monomer M-15> 6.68g (50mmol) of 4-pyridinepropanol (Tokyo Chemical Industry Co., Ltd.) was dissolved in 10mL of dehydrated THF. A solution of 8.47g (60mmol) of acrylic acid 2-isocyanate ethyl ester dissolved in 10mL of dehydrated THF was added dropwise to this solution over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 9.87g of monomer M-15.

[0150] [ka]

[0151] (Synthesis Example 8) <Synthesis of Monomer M-16> 5.41g (50mmol) of 4-(aminomethyl)pyridine (Tokyo Chemical Industry Co., Ltd.) was dissolved in 10mL of dehydrated THF. A solution of 8.47g (60mmol) of acrylic acid 2-isocyanate ethyl ester dissolved in 10mL of dehydrated THF was added dropwise to this solution over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 8.91g of monomer M-16.

[0152] [ka]

[0153] (Synthesis Example 9) <Synthesis of Monomer M-17> 11.16g (50mmol) of intermediate 2 was dissolved in 20mL of dehydrated THF. To this solution, 9.25g (60mmol) of N-(3-isocyanatepropyl)acrylamide (manufactured by Chemieliva Pharmaceutical Co.,Ltd.) dissolved in 10mL of dehydrated THF was added dropwise over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 14.22g of monomer M-17.

[0154] [ka]

[0155] (Synthesis Example 10) <Synthesis of Monomer M-18> 9.76 g (50 mmol) of intermediate 4 was dissolved in 20 mL of dehydrated THF. A solution of 9.25 g (60 mmol) of N-(3-isocyanatepropyl)acrylamide dissolved in 10 mL of dehydrated THF was added dropwise to this solution over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 12.80 g of monomer M-18.

[0156] [ka]

[0157] (Synthesis Example 11) <Synthesis of Monomer M-19> 5.41g (50mmol) of 4-(aminomethyl)pyridine was dissolved in 10mL of dehydrated THF. A solution of 9.25g (60mmol) of N-(3-isocyanatepropyl)acrylamide dissolved in 10mL of dehydrated THF was added dropwise to this solution over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 9.87g of monomer M-19.

[0158] [ka]

[0159] (Synthesis Example 12) <Synthesis of Monomer M-20> 11.16g (50mmol) of intermediate 2 was dissolved in 20mL of dehydrated THF. To this solution, 11.95g (60mmol) of methacrylic acid 2-(2-isocyanate ethoxy) ethyl ester (manufactured by Chemieliva Pharmaceutical Co., Ltd.) dissolved in 10mL of dehydrated THF was dropped over 10 minutes, and then stirred at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 15.44g of monomer M-20.

[0160] [ka]

[0161] (Synthesis Example 13) <Synthesis of Monomer M-21> 9.76 g (50 mmol) of intermediate 4 was dissolved in 20 mL of dehydrated THF. To this solution, 11.95 g (60 mmol) of methacrylic acid 2-(2-isocyanate ethoxy) ethyl ester was dissolved in 10 mL of dehydrated THF, and then the solution was dropped over 10 minutes, followed by stirring at 35°C for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 14.18 g of monomer M-21.

[0162] [ka]

[0163] (Synthesis Example 14) <Synthesis of Monomer M-22> 5.41g (50mmol) of 4-(2-aminomethyl)pyridine was dissolved in 10mL of dehydrated THF. To this solution, 11.95g (60mmol) of methacrylic acid 2-(2-isocyanate ethoxy) ethyl ester was dissolved in 10mL of dehydrated THF, and then the solution was dropped over 10 minutes, followed by stirring at 35°C for 12 hours. The solvent was removed from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of hexane / ethyl acetate (volume ratio 5 / 5 to 0 / 10) as an eluent, to obtain 11.35g of monomer M-22.

[0164] [ka]

[0165] (Synthesis Example 15) <Synthesis of Monomer M-23> 14.42g (100mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 21.73g (120mmol) of 6-bromo-1-hexanol (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 200mL of methyl ethyl ketone (manufactured by Kanto Chemical Co., Ltd.), and then 27.64g of potassium carbonate (manufactured by Kanto Chemical Co., Ltd.) was added and refluxed for 24 hours. After cooling to room temperature, the mixture was filtered and the solvent was distilled off from the filtrate. The residue was dissolved in methylene chloride (manufactured by Kanto Chemical Co., Ltd.), washed with water, dried, and the solvent was distilled off. The obtained pale yellow solid was purified by silica gel column chromatography using a mixed solvent of methylene chloride (manufactured by Kanto Chemical Co., Ltd.) / hexane (manufactured by Kanto Chemical Co., Ltd.) (volume ratio 5 / 5 to 7 / 3) as an eluent, to obtain 21.50g of intermediate 5.

[0166] [ka]

[0167] Next, 12.22 g (50 mmol) of intermediate 5 was dissolved in 50 mL of ultra-dehydrated methylene chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). To this solution, 7.76 g (50 mmol) of 2-isocyanate ethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise while stirring for 30 minutes, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride (manufactured by Kanto Chemical Co., Ltd.) / methanol (manufactured by Kanto Chemical Co., Ltd.) (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 17.80 g of monomer M-23.

[0168] [ka]

[0169] (Synthesis Example 16) <Synthesis of Monomer M-24> 12.22g (50mmol) of intermediate 5 was dissolved in 50mL of ultra-dehydrated methylene chloride. 10.56g (50mmol) of 6-isocyanate hexyl methacrylate (manufactured by Chemieliva Pharmaceutical Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 19.85g of monomer M-24.

[0170] [ka]

[0171] (Synthesis Example 17) <Synthesis of Monomer M-25> 12.22g (50mmol) of intermediate 5 was dissolved in 50mL of ultra-dehydrated methylene chloride. 13.37g (50mmol) of 3-methyl-7,7-dimethyl-7-isocyanatoheptyl methacrylate (manufactured by Hong Kong Chemhere Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 22.44g of monomer M-25.

[0172] [ka]

[0173] (Synthesis Example 18) <Synthesis of Monomer M-26> 14.42g (100mmol) of 2-naphthol (Tokyo Chemical Industry Co., Ltd.) and 15.00g (120mmol) of 2-bromoethanol (Tokyo Chemical Industry Co., Ltd.) were dissolved in 200mL of methyl ethyl ketone, and then 27.64g of potassium carbonate was added and refluxed for 24 hours. After cooling to room temperature, the mixture was filtered and the solvent was distilled off from the filtrate. The residue was dissolved in methylene chloride, washed with water, dried, and the solvent was distilled off. The obtained pale yellow solid was purified by silica gel column chromatography using a mixed solvent of methylene chloride / hexane (volume ratio 5 / 5 to 7 / 3) as an eluent to obtain 15.65g of intermediate 6.

[0174] [ka]

[0175] Next, 9.41 g (50 mmol) of intermediate 6 was dissolved in 50 mL of ultra-dehydrated methylene chloride. 7.76 g (50 mmol) of 2-isocyanate ethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 15.36 g of monomer M-26.

[0176] [ka]

[0177] (Synthesis Example 19) <Synthesis of Monomer M-27> 14.42g (100mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 28.46g (120mmol) of 10-bromo-1-decanol (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 200mL of methyl ethyl ketone, and then 27.64g of potassium carbonate was added and refluxed for 24 hours. After cooling to room temperature, the mixture was filtered and the solvent was distilled off from the filtrate. The residue was dissolved in methylene chloride, washed with water, dried, and the solvent was distilled off. The obtained pale yellow solid was purified by silica gel column chromatography using a mixed solvent of methylene chloride / hexane (volume ratio 5 / 5 to 7 / 3) as an eluent to obtain 25.67g of intermediate 7.

[0178] [ka]

[0179] Next, 15.02 g (50 mmol) of intermediate 7 was dissolved in 50 mL of ultra-dehydrated methylene chloride. 7.76 g (50 mmol) of 2-isocyanate ethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 19.98 g of monomer M-27.

[0180] [ka]

[0181] (Synthesis Example 20) <Synthesis of Monomer M-28> 23.24g (200mmol) of 1,6-diaminohexane (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 100mL of methylene chloride, and 7.91g (100mmol) of pyridine (manufactured by Kanto Chemical Co., Ltd.) was added. A solution of 19.06g (100mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 30mL of methylene chloride was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 6 hours. The resulting reaction solution was washed with water, and the organic phase was isolated and dried with magnesium sulfate (manufactured by Kanto Chemical Co., Ltd.), and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride (manufactured by Kanto Chemical Co., Ltd.) / methanol (manufactured by Kanto Chemical Co., Ltd.) (volume ratio 98 / 2) as an eluent, and 23.64g of intermediate 8 was obtained.

[0182] [ka]

[0183] Next, 13.52 g (50 mmol) of intermediate 8 was dissolved in 60 mL of ultra-dehydrated methylene chloride. 7.76 g (50 mmol) of 2-isocyanate ethyl methacrylate (Tokyo Chemical Industry Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 18.52 g of monomer M-28.

[0184] [ka]

[0185] (Synthesis Example 21) <Synthesis of Monomer M-29> 12.02g (200mmol) of 1,2-diaminoethane (Tokyo Chemical Industry Co., Ltd.) was dissolved in 100mL of methylene chloride, and 7.91g (100mmol) of pyridine was added. A solution of 19.06g (100mmol) of 2-naphthalenecarbonyl chloride (Tokyo Chemical Industry Co., Ltd.) dissolved in 30mL of methylene chloride was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 6 hours. The resulting reaction solution was washed with water, and the organic phase was isolated, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 2) as an eluent, and 18.63g of intermediate 9 was obtained.

[0186] [ka]

[0187] Next, 10.71 g (50 mmol) of intermediate 9 was dissolved in 40 mL of ultra-dehydrated methylene chloride. 7.76 g (50 mmol) of 2-isocyanate ethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 18.83 g of monomer M-29.

[0188] [ka]

[0189] (Synthesis Example 22) <Synthesis of Monomer M-30> 34.46g (200mmol) of 1,6-diaminohexane (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 100mL of methylene chloride, and 7.91g (100mmol) of pyridine was added. A solution of 19.06g (100mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 30mL of methylene chloride was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 6 hours. After washing the resulting reaction solution with water, the organic phase was isolated, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 2) as an eluent, and 27.50g of intermediate 10 was obtained.

[0190] [ka]

[0191] Next, 16.32 g (50 mmol) of intermediate 10 was dissolved in 80 mL of ultra-dehydrated methylene chloride. 7.76 g (50 mmol) of 2-isocyanate ethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 22.25 g of monomer M-30.

[0192] [ka]

[0193] (Synthesis Example 23) <Synthesis of Monomer M-31> 12.22g (50mmol) of intermediate 5 was dissolved in 50mL of ultra-dehydrated methylene chloride. 7.71g (50mmol) of N-(3-isocyanatopropyl)acrylamide (manufactured by Chemieliva Pharmaceutical Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 18.85g of monomer M-31.

[0194] [ka]

[0195] (Synthesis Example 24) <Synthesis of Monomer M-32> 13.52g (50mmol) of intermediate 8 was dissolved in 60mL of ultra-dehydrated methylene chloride. 9.26g (50mmol) of 2-(2-isocyanatoethoxy)ethyl acrylate (manufactured by Chemieliva Pharmaceutical Co., Ltd.) was added dropwise to this solution over 30 minutes while stirring, and then stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98 / 1 to 95 / 5) as an eluent, to obtain 19.67g of monomer M-32.

[0196] [ka]

[0197] (Synthesis Example 25) <Synthesis of Monomer M-33> 35.5g (300mmol) of 1,6-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was heated to 60°C and dissolved, and then 0.98g (10mmol) of concentrated sulfuric acid was added little by little while stirring. Then, 17.22g (100mmol) of 2-naphthalenecarboxylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added little by little, and then the mixture was heated to 120°C and stirred for 4 hours. After cooling to room temperature, 5N aqueous sodium hydroxide solution (manufactured by Kanto Chemical Co., Ltd.) was added until the pH became 7, and the mixture was extracted with 300mL of ethyl acetate (manufactured by Kanto Chemical Co., Ltd.) and washed with water. The organic phase was isolated, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of ethyl acetate / hexane (volume ratio 5 / 5) as an eluent, and 21.5g of intermediate 11 was obtained.

[0198] [ka]

[0199] Next, 22.71 g (100 mmol) of intermediate 11 and 0.26 g (0.04 mmol) of dibutyltin laurate (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to dry tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.). A solution of 14.12 g (155 mmol) of 2-acryloyloxyethyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 10 mL of dry tetrahydrofuran was added dropwise to this solution over 15 minutes, and then the mixture was stirred at room temperature for 12 hours. The solvent was distilled off from the resulting reaction solution, and the residue was purified by silica gel column chromatography using a mixed solvent of ethyl acetate / hexane (volume ratio 5 / 5) as an eluent, to obtain 28.8 g of monomer M-33.

[0200] [ka]

[0201] The structures of the monomers M-9 to M-33 obtained in Monomer Synthesis Examples 1 to 25 are shown in Table 1.

[0202] [Table 1]

[0203] Example 1 <Synthesis of copolymer CP-1> 10.4 parts by mass of monomer SM-1 (X-22-2404, in general formula (1), R1 = methyl group, R2 = methyl group, n = 420, manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7 parts by mass of acrylic acid (AA) (manufactured by Tokyo Chemical Industry Co., Ltd.), 69.9 parts by mass of monomer M-1 represented by the following formula (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.94 parts by mass of 2,2'-azoiso(butyronitrile) (AIBN) (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 252 parts by mass of dimethylformamide (DMF) (manufactured by Kanto Chemical Co., Ltd.). This solution was dropped into 28 parts by mass of DMF heated to 80 ° C. under a nitrogen stream over 30 minutes, and then stirred at 80 ° C. for 5 hours. The mixture was cooled to room temperature and the resulting reaction solution was dropped into 500 mL of water. The precipitate was separated by filtration and dried under reduced pressure to obtain 96.2 parts by mass of copolymer CP-1 (weight average molecular weight (Mw): 20,200).

[0204] [ka]

[0205] Example 2 <Synthesis of copolymer CP-2> 97.1 parts by mass of copolymer CP-2 (Mw: 23,400) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-2 (KF-2012, in general formula (1), R1 = methyl group, R2 = methyl group, n = 4,600, manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7 parts by mass of AA, 69.9 parts by mass of monomer M-1, and 0.81 parts by mass of AIBN were used.

[0206] Example 3 <Synthesis of copolymer CP-3> 96.5 parts by mass of copolymer CP-3 (Mw: 30,900) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-3 (X-22-2426, in general formula (1), R1 = methyl group, R2 = methyl group, n = 12,000, manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7 parts by mass of AA, 69.9 parts by mass of monomer M-1, and 0.72 parts by mass of AIBN were used.

[0207] Example 4 <Synthesis of copolymer CP-4> Except for using 10.4 parts by mass of monomer SM-4 (X-22-2445, in general formula (1), R1 = hydrogen, R2 = "CH2 = CH-COO-", n = 1,600, manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7 parts by mass of AA, 69.9 parts by mass of monomer M-1, and 0.64 parts by mass of AIBN, 96.0 parts by mass of copolymer CP-4 (Mw: 35,900) was obtained in the same manner as in Example 1.

[0208] Example 5 <Synthesis of copolymer CP-5> 96.5 parts by mass of copolymer CP-5 (Mw: 34,500) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-5 (X-22-164A, in general formula (1), R1 = methyl group, R2 = "CH2 = C(CH3) -COO-", n = 450, manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7 parts by mass of AA, 69.9 parts by mass of monomer M-1, and 0.66 parts by mass of AIBN were used.

[0209] Example 6 <Synthesis of copolymer CP-6> 96.2 parts by mass of copolymer CP-6 (Mw: 48,100) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-6 (X-22-164E, in general formula (1), R1 = methyl group, R2 = "CH2 = C(CH3) -COO-", n = 3,900, manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7 parts by mass of AA, 69.9 parts by mass of monomer M-1, and 0.45 parts by mass of AIBN were used.

[0210] Example 7 <Synthesis of copolymer CP-7> 10.4 parts by mass of monomer SM-1, 21.0 parts by mass of AA, 68.7 parts by mass of monomer M-2 represented by the following formula (manufactured by Chemieliva Pharmaceuticals), 2.00 parts by mass of AIBN, and 0.32 parts by mass of 3-mercaptopropionic acid (3MPA) were dissolved in 252 parts by mass of dimethylformamide (DMF) (manufactured by Kanto Chemical Co., Ltd.). This solution was dropped into 28 parts by mass of DMF heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of water. The precipitate was filtered and dried under reduced pressure to obtain 97.1 parts by mass of copolymer CP-7 (Mw: 4,400).

[0211] [ka]

[0212] Example 8 <Synthesis of copolymer CP-8> 10.4 parts by mass of monomer SM-1, 24.6 parts by mass of AA, 65.1 parts by mass of monomer M-3 (manufactured by Chemieliva Pharmaceuticals) represented by the following formula, and 0.29 parts by mass of AIBN were dissolved in 216 parts by mass of DMF. This solution was dropped into 24 parts by mass of DMF heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of water. The precipitate was filtered and dried under reduced pressure to obtain 96.5 parts by mass of copolymer CP-8 (Mw: 53,000).

[0213] [ka]

[0214] Example 9 <Synthesis of copolymer CP-9> 97.2 parts by mass of copolymer CP-9 (Mw: 16,500) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-1, 18.8 parts by mass of methacrylic acid (MA) (manufactured by Tokyo Chemical Industry Co., Ltd.), 70.8 parts by mass of monomer M-9, and 0.91 parts by mass of AIBN were used.

[0215] Example 10 <Synthesis of copolymer CP-10> 97.6 parts by mass of copolymer CP-10 (Mw: 17,400) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-1, 18.8 parts by mass of MA, 70.8 parts by mass of monomer M-10, and 0.85 parts by mass of AIBN were used.

[0216] Example 11 <Synthesis of copolymer CP-11> 97.0 parts by mass of copolymer CP-11 (Mw: 21,200) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-1, 18.8 parts by mass of MA, 70.8 parts by mass of monomer M-11, and 0.67 parts by mass of AIBN were used.

[0217] Example 12 <Synthesis of copolymer CP-12> Except for using 10.4 parts by mass of monomer SM-1, 18.8 parts by mass of MA, 70.8 parts by mass of monomer M-12, and 0.64 parts by mass of AIBN, 97.9 parts by mass of copolymer CP-12 (Mw: 23,800) was obtained in the same manner as in Example 1.

[0218] (Example 13) <Synthesis of copolymer CP-13> 97.3 parts by mass of copolymer CP-13 (Mw: 28,200) was obtained in the same manner as in Example 1, except that 10.4 parts by mass of monomer SM-1, 18.8 parts by mass of MA, 70.8 parts by mass of monomer M-13, and 0.60 parts by mass of AIBN were used.

[0219] Example 14 <Synthesis of copolymer CP-14> 97.7 parts by mass of copolymer CP-14 (Mw: 33,200) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-14, and 0.58 parts by mass of AIBN were used.

[0220] Example 15 <Synthesis of copolymer CP-15> 98.0 parts by mass of copolymer CP-15 (Mw: 31,900) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-15, and 0.64 parts by mass of AIBN were used.

[0221] Example 16 <Synthesis of copolymer CP-16> 97.3 parts by mass of copolymer CP-16 (Mw: 33,700) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-16, and 0.69 parts by mass of AIBN were used.

[0222] (Example 17) <Synthesis of copolymer CP-17> 97.0 parts by mass of copolymer CP-17 (Mw: 33,000) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-17, and 0.55 parts by mass of AIBN were used.

[0223] (Example 18) <Synthesis of copolymer CP-18> 96.9 parts by mass of copolymer CP-18 (Mw: 32,800) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-18, and 0.57 parts by mass of AIBN were used.

[0224] (Example 19) <Synthesis of copolymer CP-19> Except for using 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-19, and 0.68 parts by mass of AIBN, 97.8 parts by mass of copolymer CP-19 (Mw: 32,400) was obtained in the same manner as in Example 1.

[0225] (Example 20) <Synthesis of copolymer CP-20> 97.7 parts by mass of copolymer CP-20 (Mw: 34,100) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-20, and 0.52 parts by mass of AIBN were used.

[0226] Example 21 <Synthesis of copolymer CP-21> 97.9 parts by mass of copolymer CP-21 (Mw: 32,900) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-21, and 0.54 parts by mass of AIBN were used.

[0227] Example 22 <Synthesis of copolymer CP-22> 97.6 parts by mass of copolymer CP-22 (Mw: 32,100) was obtained in the same manner as in Example 1, except that 6.4 parts by mass of monomer SM-2, 19.1 parts by mass of MA, 74.5 parts by mass of monomer M-22, and 0.61 parts by mass of AIBN were used.

[0228] Example 23 <Synthesis of copolymer CP-23> 97.0 parts by mass of copolymer CP-23 (Mw: 4,900) was obtained in the same manner as in Example 7, except that 10.4 parts by mass of monomer SM-1, 18.8 parts by mass of MA, 70.8 parts by mass of monomer M-9, 1.52 parts by mass of AIBN, and 0.25 parts by mass of 3-mercaptopropionic acid were used.

[0229] Example 24 <Synthesis of copolymer CP-24> Except for using 10.4 parts by mass of monomer SM-2, 18.8 parts by mass of MA, 70.8 parts by mass of monomer M-9, and 0.18 parts by mass of AIBN, 96.8 parts by mass of copolymer CP-24 (Mw: 52,200) was obtained in the same manner as in Example 8.

[0230] (Example 25) <Synthesis of copolymer CP-25> 5.8 parts by mass of monomer SM-1, 23.0 parts by mass of AA, 71.2 parts by mass of monomer M-4 (manufactured by Chemieliva Pharmaceuticals) represented by the following formula, and 0.92 parts by mass of AIBN were dissolved in 252 parts by mass of methyl ethyl ketone (MEK) (manufactured by Kanto Chemical Co., Ltd.). This solution was dropped into 28 parts by mass of MEK heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of hexane (manufactured by Kanto Chemical Co., Ltd.). The precipitate was filtered and dried under reduced pressure to obtain 98.4 parts by mass of copolymer CP-25 (Mw: 24,400).

[0231] [ka]

[0232] (Example 26) <Synthesis of copolymer CP-26> Except for using 5.8 parts by mass of monomer SM-2, 23.0 parts by mass of AA, 71.2 parts by mass of monomer M-4, and 0.81 parts by mass of AIBN, 98.6 parts by mass of copolymer CP-26 (Mw: 25,200) was obtained in the same manner as in Example 25.

[0233] Example 27 <Synthesis of copolymer CP-27> Except for using 5.8 parts by mass of monomer SM-3, 23.0 parts by mass of AA, 71.2 parts by mass of monomer M-4, and 0.72 parts by mass of AIBN, 98.5 parts by mass of copolymer CP-27 (Mw: 27,500) was obtained in the same manner as in Example 25.

[0234] (Example 28) <Synthesis of copolymer CP-28> Except for using 5.8 parts by mass of monomer SM-4, 23.0 parts by mass of AA, 71.2 parts by mass of monomer M-4, and 0.63 parts by mass of AIBN, 98.3 parts by mass of copolymer CP-28 (Mw: 31,100) was obtained in the same manner as in Example 25.

[0235] (Example 29) <Synthesis of copolymer CP-29> Except for using 5.8 parts by mass of monomer SM-5, 23.0 parts by mass of AA, 71.2 parts by mass of monomer M-4, and 0.55 parts by mass of AIBN, 98.0 parts by mass of copolymer CP-29 (Mw: 33,400) was obtained in the same manner as in Example 25.

[0236] (Example 30) <Synthesis of copolymer CP-30> Except for using 5.8 parts by mass of monomer SM-6, 23.0 parts by mass of AA, 71.2 parts by mass of monomer M-4, and 0.45 parts by mass of AIBN, 98.6 parts by mass of copolymer CP-30 (Mw: 37,500) was obtained in the same manner as in Example 25.

[0237] (Example 31) <Synthesis of copolymer CP-31> 5.8 parts by mass of monomer SM-1, 25.3 parts by mass of AA, 68.9 parts by mass of monomer M-5 (manufactured by Chemieliva Pharmaceuticals) represented by the following formula, 2.04 parts by mass of AIBN, and 0.33 parts by mass of 3-mercaptopropionic acid were dissolved in 252 parts by mass of MEK. This solution was dropped into 28 parts by mass of MEK heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of hexane. The precipitate was filtered and dried under reduced pressure to obtain 98.1 parts by mass of copolymer CP-31 (Mw: 4,500).

[0238] [ka]

[0239] Example 32 <Synthesis of copolymer CP-32> 5.8 parts by mass of monomer SM-1, 28.1 parts by mass of AA, 66.1 parts by mass of monomer M-6 (manufactured by Hong Kong Chemhere) represented by the following formula, and 0.27 parts by mass of AIBN were dissolved in 216 parts by mass of MEK. This solution was dropped into 24 parts by mass of MEK heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of hexane. The precipitate was filtered and dried under reduced pressure to obtain 98.7 parts by mass of copolymer CP-32 (Mw: 50,900).

[0240] [ka]

[0241] (Example 33) <Synthesis of copolymer CP-33> 98.6 parts by mass of copolymer CP-33 (Mw: 4,600) was obtained in the same manner as in Example 31, except that 5.8 parts by mass of monomer SM-1, 25.9 parts by mass of AA, 68.3 parts by mass of monomer M-7 (manufactured by Hong Kong Chemhere) represented by the following formula, 2.01 parts by mass of AIBN, and 0.33 parts by weight of 3-mercaptopropionic acid were used.

[0242] [ka]

[0243] (Example 34) <Synthesis of copolymer CP-34> 98.1 parts by mass of copolymer CP-34 (Mw: 51,100) was obtained in the same manner as in Example 32, except that 5.8 parts by mass of monomer SM-1, 26.9 parts by mass of AA, 67.3 parts by mass of monomer M-8 (manufactured by Chemieliva Pharmaceuticals) represented by the following formula, and 0.26 parts by mass of AIBN were used.

[0244] [ka]

[0245] (Example 35) <Synthesis of copolymer CP-35> Except for using 5.8 parts by mass of monomer SM-1, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-23, and 0.86 parts by mass of AIBN, 98.1 parts by mass of copolymer CP-35 (Mw: 20,100) was obtained in the same manner as in Example 25.

[0246] (Example 36) <Synthesis of copolymer CP-36> Except for using 5.8 parts by mass of monomer SM-1, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-24, and 0.82 parts by mass of AIBN, 98.7 parts by mass of copolymer CP-36 (Mw: 22,200) was obtained in the same manner as in Example 25.

[0247] (Example 37) <Synthesis of copolymer CP-37> Except for using 5.8 parts by mass of monomer SM-1, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-25, and 0.65 parts by mass of AIBN, 98.2 parts by mass of copolymer CP-37 (Mw: 28,600) was obtained in the same manner as in Example 25.

[0248] (Example 38) <Synthesis of copolymer CP-38> Except for using 5.8 parts by mass of monomer SM-1, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-26, and 0.77 parts by mass of AIBN, 98.5 parts by mass of copolymer CP-38 (Mw: 29,100) was obtained in the same manner as in Example 25.

[0249] (Example 39) <Synthesis of copolymer CP-39> Except for using 5.8 parts by mass of monomer SM-1, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-27, and 0.61 parts by mass of AIBN, 98.6 parts by mass of copolymer CP-39 (Mw: 30,300) was obtained in the same manner as in Example 25.

[0250] (Example 40) <Synthesis of copolymer CP-40> Except for using 11.6 parts by mass of monomer SM-2, 21.6 parts by mass of MA, 66.8 parts by mass of monomer M-28, and 0.61 parts by mass of AIBN, 98.0 parts by mass of copolymer CP-40 (Mw: 33,600) was obtained in the same manner as in Example 25.

[0251] (Example 41) <Synthesis of copolymer CP-41> Except for using 11.6 parts by mass of monomer SM-2, 21.6 parts by mass of MA, 66.8 parts by mass of monomer M-29, and 0.57 parts by mass of AIBN, 98.8 parts by mass of copolymer CP-41 (Mw: 34,200) was obtained in the same manner as in Example 25.

[0252] (Example 42) <Synthesis of copolymer CP-42> Except for using 11.6 parts by mass of monomer SM-2, 21.6 parts by mass of MA, 66.8 parts by mass of monomer M-30, and 0.52 parts by mass of AIBN, the same procedure as in Example 25 was followed to obtain 98.4 parts by mass of copolymer CP-42 (Mw: 35,500).

[0253] (Example 43) <Synthesis of copolymer CP-43> Except for using 11.6 parts by mass of monomer SM-2, 21.6 parts by mass of MA, 66.8 parts by mass of monomer M-31, and 0.48 parts by mass of AIBN, the same procedure as in Example 25 was followed to obtain 98.9 parts by mass of copolymer CP-43 (Mw: 37,200).

[0254] (Example 44) <Synthesis of copolymer CP-44> Except for using 11.6 parts by mass of monomer SM-2, 21.6 parts by mass of MA, 66.8 parts by mass of monomer M-32, and 0.47 parts by mass of AIBN, 98.2 parts by mass of copolymer CP-44 (Mw: 36,900) was obtained in the same manner as in Example 25.

[0255] (Example 45) <Synthesis of copolymer CP-45> Except for using 11.6 parts by mass of monomer SM-2, 21.6 parts by mass of MA, 66.8 parts by mass of monomer M-33, and 0.41 parts by mass of AIBN, the same procedure as in Example 25 was followed to obtain 97.8 parts by mass of copolymer CP-45 (Mw: 40,100).

[0256] (Example 46) <Synthesis of copolymer CP-46> Except for using 5.8 parts by mass of monomer SM-2, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-23, 1.39 parts by mass of AIBN, and 0.22 parts by mass of 3-mercaptopropionic acid, 98.1 parts by mass of copolymer CP-46 (Mw: 4,500) was obtained in the same manner as in Example 31.

[0257] (Example 47) <Synthesis of copolymer CP-47> Except for using 5.8 parts by mass of monomer SM-3, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-23, 1.39 parts by mass of AIBN, and 0.31 parts by mass of 3-mercaptopropionic acid, 98.6 parts by mass of copolymer CP-47 (Mw: 4,800) was obtained in the same manner as in Example 31.

[0258] (Example 48) <Synthesis of copolymer CP-48> Except for using 5.8 parts by mass of monomer SM-4, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-23, and 0.17 parts by mass of AIBN, 98.8 parts by mass of copolymer CP-48 (Mw: 51,000) was obtained in the same manner as in Example 32.

[0259] (Example 49) <Synthesis of copolymer CP-49> Except for using 5.8 parts by mass of monomer SM-5, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-23, 1.43 parts by mass of AIBN, and 0.23 parts by mass of 3-mercaptopropionic acid, 98.7 parts by mass of copolymer CP-49 (Mw: 4,000) was obtained in the same manner as in Example 31.

[0260] (Example 50) <Synthesis of copolymer CP-50> Except for using 5.8 parts by mass of monomer SM-6, 20.5 parts by mass of MA, 73.6 parts by mass of monomer M-23, and 0.14 parts by mass of AIBN, 98.0 parts by mass of copolymer CP-50 (Mw: 51,900) was obtained in the same manner as in Example 32.

[0261] Comparative Example 1 <Synthesis of comparative copolymer RCP-1> 16.5 parts by mass of AA, 83.5 parts by mass of monomer M-1, and 0.91 parts by mass of AIBN were dissolved in 252 parts by mass of DMF. This solution was dropped into 28 parts by mass of DMF heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of water. The precipitate was filtered and dried under reduced pressure to obtain 96.5 parts by mass of comparative copolymer RCP-1 (Mw: 27,800).

[0262] Comparative Example 2 <Synthesis of comparative copolymer RCP-2> 97.2 parts by mass of comparative copolymer RCP-2 (Mw: 30,500) was obtained in the same manner as in Comparative Example 1, except that 23.4 parts by mass of AA, 76.6 parts by mass of monomer M-2, and 0.96 parts by mass of AIBN were used.

[0263] Comparative Example 3 <Synthesis of comparative copolymer RCP-3> 97.7 parts by mass of comparative copolymer RCP-3 (Mw: 35,600) was obtained in the same manner as in Comparative Example 1, except that 27.4 parts by mass of AA, 72.6 parts by mass of monomer M-3, and 1.00 part by mass of AIBN were used.

[0264] Comparative Example 4 <Synthesis of comparative copolymer RCP-4> 32.7 parts by mass of MA, 67.3 parts by mass of monomer M-3, 2.40 parts by mass of AIBN, and 0.39 parts by mass of 3-mercaptopropionic acid were dissolved in 252 parts by mass of DMF. This solution was dropped into 28 parts by mass of DMF heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of water. The precipitate was filtered and dried under reduced pressure to obtain 96.3 parts by mass of comparative copolymer RCP-4 (Mw: 4,500).

[0265] Comparative Example 5 <Synthesis of comparative copolymer RCP-5> 24.4 parts by mass of AA, 75.6 parts by mass of monomer M-4, and 0.95 parts by mass of AIBN were dissolved in 252 parts by mass of MEK. This solution was dropped into 28 parts by mass of MEK heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500mL of hexane (Kanto Chemical Co., Ltd.). The precipitate was filtered and dried under reduced pressure to obtain 98.8 parts by mass of comparative copolymer RCP-5 (Mw: 28,600).

[0266] Comparative Example 6 <Synthesis of comparative copolymer RCP-6> 98.3 parts by mass of comparative copolymer RCP-6 (Mw: 31,100) was obtained in the same manner as in Comparative Example 5, except that 26.7 parts by mass of AA, 73.3 parts by mass of monomer M-5, and 0.95 parts by mass of AIBN were used.

[0267] Comparative Example 7 <Synthesis of comparative copolymer RCP-7> 98.1 parts by mass of comparative copolymer RCP-7 (Mw: 34,300) was obtained in the same manner as in Comparative Example 5, except that 29.8 parts by mass of AA, 70.2 parts by mass of monomer M-6, and 0.91 parts by mass of AIBN were used.

[0268] Comparative Example 8 <Synthesis of comparative copolymer RCP-8> 98.6 parts by mass of comparative copolymer RCP-8 (Mw: 38,400) was obtained in the same manner as in Comparative Example 5, except that 27.5 parts by mass of AA, 72.5 parts by mass of monomer M-7, and 0.73 parts by mass of AIBN were used.

[0269] Comparative Example 9 <Synthesis of comparative copolymer RCP-9> 98.1 parts by mass of comparative copolymer RCP-9 (Mw: 39,100) was obtained in the same manner as in Comparative Example 5, except that 28.6 parts by mass of AA, 71.4 parts by mass of monomer M-8, and 0.65 parts by mass of AIBN were used.

[0270] Comparative Example 10 <Synthesis of comparative copolymer RCP-10> 32.3 parts by mass of MA, 67.7 parts by mass of monomer M-8, and 0.26 parts by mass of AIBN were dissolved in 216 parts by mass of MEK. This solution was dropped into 24 parts by mass of MEK heated to 80°C under a nitrogen stream over 30 minutes, and then stirred at 80°C for 5 hours. The reaction solution was cooled to room temperature and dropped into 500 mL of hexane. The precipitate was filtered and dried under reduced pressure to obtain 98.4 parts by mass of comparative copolymer RCP-10 (Mw: 51,100).

[0271] Comparative Example 11 <Synthesis of comparative copolymer RCP-11> 97.9 parts by mass of comparative copolymer RCP-11 (Mw: 24,500) was obtained in the same manner as in Comparative Example 1, except that 10.4 parts by mass of SM-2, 89.6 parts by mass of monomer M-1, and 0.52 parts by mass of AIBN were used.

[0272] Comparative Example 12 <Synthesis of comparative copolymer RCP-12> 97.0 parts by mass of comparative copolymer RCP-12 (Mw: 23,300) was obtained in the same manner as in Comparative Example 1, except that 10.4 parts by mass of SM-2, 89.6 parts by mass of monomer AA, and 1.84 parts by mass of AIBN were used.

[0273] The compositions, parts by mass, and weight average molecular weights (Mw) of copolymers CP-1 to CP-50 synthesized in Examples 1 to 50 and copolymers RCP-1 to RCP-12 synthesized in Comparative Examples 1 to 12 are summarized in Tables 2 and 3.

[0274] [Table 2]

[0275] [Table 3]

[0276] (Example 51) <Preparation of pigment dispersion PD-1> 40.00 parts by mass of ion-exchanged water and 5.0 parts by mass of ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a glass container and stirred, after which 0.61 parts by mass of dimethylaminoethanol (manufactured by Tokyo Chemical Industry Co., Ltd.) as a base and 2.50 parts by mass of copolymer CP-1 prepared in Example 1 as a dispersant were added and dissolved. Next, 50.00 parts by mass of titanium oxide JR-405 (manufactured by Teika Co., Ltd.) as a pigment were added little by little while stirring, and then stirred for 6 hours. 540 parts by mass of zirconia beads with a diameter of 2 mm were added, and dispersion treatment was performed for 48 hours at a rotation speed of 90 rpm using a Big Rotor BR-2 (manufactured by AS ONE Co., Ltd.). The contents were filtered through a membrane filter with a pore size of 10 μm, and an adjusted amount of ion-exchanged water was added to obtain 100.00 parts by mass of pigment dispersion PD-1 (pigment solid content concentration: 50%).

[0277] <Preparation of Water-Based Ink-1> 20.0 parts by mass of pigment dispersion PD-1, 18.0 parts by mass of ethylene glycol, 4.0 parts by mass of 3-methyl-1,3-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.0 part by mass of Zonyl FS-300 (fluorine-based surfactant, solids content 40%, manufactured by Dupont), 0.3 parts by mass of triethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.7 parts by mass of 1,2-benzothiazolin-3-one (manufactured by Tokyo Chemical Industry Co., Ltd.), and 56.0 parts by mass of ion-exchanged water were mixed and stirred for 1 hour, and then filtered through a membrane filter with a pore size of 5.0 μm to obtain ink Ink-1.

[0278] (Example 52) to (Example 108) Pigment dispersions PD-2 (pigment solids concentration: 50%) to PD-58 (pigment solids concentration: 50%) and inks Ink-2 to Ink-58 were obtained in the same manner as in Example 51, except that the dispersants, pigments, and bases shown in Tables 4 to 5 were used instead of the dispersants, pigments, and bases used in Example 51. In Tables 4 to 5, DMAEtOH stands for dimethylaminoethanol.

[0279] [Table 4]

[0280] [Table 5]

[0281] (Comparative Example 13) to (Comparative Example 28) Comparative pigment dispersions RPD-1 (pigment solids concentration: 50%) to RPD-16 (pigment solids concentration: 50%) and comparative inks RInk-1 to RInk-16 were obtained in the same manner as in Example 51, except that the dispersants, pigments, and bases shown in Table 6 were used instead of the dispersants, pigments, and bases used in Example 51. In Table 6, DMAEtOH stands for dimethylaminoethanol.

[0282] Comparative Example 29 <Preparation of pigment dispersion RPD-17> 34.17 parts by mass of ion-exchanged water and 5.0 parts by mass of ethylene glycol (manufactured by Tokyo Kasei Co., Ltd.) were placed in a glass container, and after stirring, 8.33 parts by mass of a silicone-based graft polymer (trade name: Cymac US-450, manufactured by Toa Gosei Co., Ltd., an aqueous solution with a solid content of 30%) was added as a dispersant. Next, 50.00 parts by mass of titanium oxide JR-405 (manufactured by Teika Co., Ltd.) was added little by little as a pigment while stirring, and then stirred for 6 hours. 540 parts by mass of zirconia beads with a diameter of 2 mm were added, and the mixture was dispersed for 48 hours at a rotation speed of 90 rpm using a Big Rotor BR-2 (manufactured by AS ONE Co., Ltd.). The contents were filtered through a membrane filter with a pore size of 10 μm, and an adjusted amount of ion-exchanged water was added to obtain 100.00 parts by mass of pigment dispersion RPD-17 (pigment solid content concentration: 50%).

[0283] <Preparation of Water-Based Ink RInk-17> 20.0 parts by mass of pigment dispersion RPD-17, 18.0 parts by mass of ethylene glycol, 4.0 parts by mass of 3-methyl-1,3-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.0 part by mass of Zonyl FS-300 (fluorine-based surfactant, solids content 40%, manufactured by Dupont), 0.3 parts by mass of triethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.7 parts by mass of 1,2-benzothiazolin-3-one (manufactured by Tokyo Chemical Industry Co., Ltd.), and 56.0 parts by mass of ion-exchanged water were mixed and stirred for 1 hour, and then filtered through a membrane filter having a pore size of 5.0 μm to obtain ink RInk-17.

[0284] [Table 6]

[0285] (Evaluation of storage stability of pigment dispersion) Each pigment dispersion was filled into a glass container and stored at 70°C for 2 weeks, and the rate of change in viscosity after storage relative to the viscosity before storage was calculated using the following formula and evaluated according to the following criteria. A viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity at 25°C at 50 revolutions. Viscosity change rate (%) = 100 x (viscosity of pigment dispersion after storage - viscosity of pigment dispersion before storage) / viscosity of pigment dispersion before storage [Evaluation Criteria] A: Viscosity change rate is within ±5% B: Viscosity change rate exceeds ±5% and is within ±8% C: Viscosity change rate exceeds ±8% and is within ±10% D: Viscosity change rate exceeds ±10% and is within ±30%

[0286] (Evaluation of ink storage stability) Each ink was filled into an ink cartridge and stored at 70°C for one week, and the rate of change in viscosity after storage relative to the viscosity before storage was calculated using the following formula and evaluated according to the following criteria. A viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity at 25°C at 50 revolutions. Viscosity change rate (%) = 100 x (viscosity of ink after storage - viscosity of ink before storage) / viscosity of ink before storage [Evaluation Criteria] A: Viscosity change rate is within ±5% B: Viscosity change rate exceeds ±5% and is within ±8% C: Viscosity change rate exceeds ±8% and is within ±10% D: Viscosity change rate exceeds ±10% and is within ±30%

[0287] (Evaluation of ink redispersibility) Sedimentation of the ink components by leaving the ink still requires leaving the ink for a long time, so a centrifuge was used to accelerate the sedimentation of the ink components. First, the ink was poured into a test tube PYREX (registered trademark) IWAKI TE-32 (16.5 mm x 105 mm, manufactured by AGC) to a depth of 45 mm, and the tube was covered with a silicone stopper to prepare an evaluation sample. Next, in order to define the initial state of the evaluation sample, immediately after the evaluation sample was prepared, the tip of a 2-3 mm pipette was immersed in the ink liquid surface to collect about 0.02 mL (about 20 mg) of ink. Of the collected ink, 4-10 mg was placed in a 50 mL sample bottle and diluted 4000 times with ion-exchanged water. The sample bottle was placed on the stand of a mix rotor VMR-5R (manufactured by AS ONE) and rotated at a rotation speed of 60 rpm for 10 minutes or more, and then immediately the absorption spectrum of UV-VIS (Ultraviolet-Visible Absorption Spectroscopy) was measured using an ultraviolet-visible-near infrared spectrophotometer V-680 (manufactured by JASCO Corporation) to prepare a reference spectrum before accelerated sedimentation. The measurement conditions are as follows. -UV-VIS measurement conditions- Wavelength range: 350~800nm Cell length: 3mm Measurement conditions: UV / VIS band width 2.0 nm, NIR band width 4.0 nm, response FAST, scanning speed 400 nm / min Next, the evaluation sample was placed in an inverter hematocrit centrifuge 3220 (KUBOTA) and accelerated sedimentation was performed at 300 rpm for 14 hours. The evaluation sample was gently turned sideways and gently placed on a mix rotor VMR-5R and rotated at 60 rpm for 1, 2, 3, or 4 minutes, after which the evaluation sample was immediately returned to its original vertical orientation, and a sample was taken from the ink surface in the same manner as above, and the absorption spectrum was measured, and the redispersion spectrum was obtained after 1, 2, 3, or 4 minutes. The redispersibility of the ink was evaluated according to the following criteria by calculating the rate of change of the redispersion spectrum relative to the reference spectrum from the following formula. Redispersibility (%) = 100 x (absorbance at peak wavelength of redispersion spectrum / absorbance at peak wavelength of reference spectrum) [Evaluation Criteria] A: Redispersion spectrum after 1 minute shows redispersion rate of 90% or more B: Redispersion spectrum after 2 minutes shows redispersion rate of 90% or more C: Redispersion spectrum after 3 minutes shows redispersion rate of 90% or more D: Redispersion spectrum after 4 minutes shows redispersion rate of 90% or more E: Redispersion spectrum after 4 minutes shows redispersion rate of 89% or less

[0288] The results of storage stability and redispersibility of pigment dispersions PD-1 to PD-58 and inks Ink-1 to Ink-58 of Examples 51 to 108, and comparative pigment dispersions RPD-1 to RPD-17 and comparative inks RInk-1 to RInk-17 of Comparative Examples 13 to 29 are summarized in Tables 7 to 9.

[0289] [Table 7]

[0290] [Table 8]

[0291] [Table 9]

[0292] (Example 109) <Preparation of solar cell backsheet BS-1> -Preparation of protective layer forming solution PC-1- In a glass container, 45 parts by mass of dimethylformamide (manufactured by Kanto Chemical Co., Ltd.) and 36 parts by mass of the copolymer CP-9 obtained in Example 9 were added and stirred to dissolve. Next, 10 parts by mass of titanium oxide JR-405 were added little by little while stirring, and then stirred for 6 hours. 540.0 parts by mass of zirconia beads with a diameter of 1 mm were added, and the mixture was dispersed for 2 days at a rotation speed of 90 rpm using a Big Rotor BR-2 (manufactured by AS ONE Co., Ltd.). The contents were filtered through a membrane filter with a pore size of 10 μm, and an adjusted amount of dimethylformamide (manufactured by Kanto Chemical Co., Ltd.) and 4.0 parts by mass of hexamethylene diisocyanate (manufactured by Tokyo Kasei Co., Ltd.) were added to obtain 100.0 parts by mass of protective layer forming solution PC-1 (pigment solid content concentration: 10%).

[0293] -Preparation of solar cell backsheet BS-1- The protective layer forming liquid PC-1 was applied to the surface of a 75 μm-thick white polyethylene terephthalate film (Lumirror MX11, manufactured by Toray Industries, Inc.) using a wire bar, and dried at 150°C for 5 minutes to provide a protective layer with an average film thickness of 2 μm. The film was then aged at 50°C for 3 days to obtain a solar cell backsheet BS-1.

[0294] (Example 110) <Preparation of solar cell backsheet BS-2> A protective layer forming liquid PC-2 and a solar cell back sheet BS-2 were obtained in the same manner as in Example 109, except that the copolymer CP-14 prepared in Example 14 was used instead of the copolymer CP-9 used in Example 109.

[0295] (Example 111) <Preparation of solar cell backsheet BS-3> A protective layer forming liquid PC-3 and a solar cell back sheet BS-3 were obtained in the same manner as in Example 109, except that the copolymer CP-35 prepared in Example 35 was used instead of the copolymer CP-9 used in Example 109.

[0296] (Example 112) <Preparation of solar cell backsheet BS-4> A protective layer forming liquid PC-4 and a solar cell back sheet BS-4 were obtained in the same manner as in Example 109, except that the copolymer CP-40 prepared in Example 40 was used instead of the copolymer CP-9 used in Example 109.

[0297] (Comparative Example 30) <Preparation of comparative solar cell backsheet RBS-1> A comparative protective layer forming liquid RPC-1 and a comparative solar cell back sheet RBS-1 were obtained in the same manner as in Example 109, except that the comparative copolymer RCP-3 prepared in Comparative Example 3 was used instead of the copolymer CP-9 used in Example 109.

[0298] (Comparative Example 31) <Preparation of comparative solar cell backsheet RBS-2> A comparative protective layer forming liquid RPC-2 and a comparative solar cell back sheet RBS-2 were obtained in the same manner as in Example 109, except that the copolymer RCP-8 prepared in Comparative Example 8 was used instead of the copolymer CP-9 used in Example 109.

[0299] (Weather resistance evaluation) -Measurement of initial breaking elongation Es- Each of the produced solar cell backsheets was cut into a size of 1 cm x 10 cm, and the breaking elongation of the solar cell backsheet was measured based on ASTM-D882 (ANNUAL BOOK OF ASTM STANDARDS 1999 edition), and the result was taken as the initial breaking elongation Es.

[0300] -Measurement of breaking elongation Ee after aging- Using a Super Xenon Weather Meter SX75 (manufactured by Suga Test Instruments), the black panel temperature was 65°C, the relative humidity was 50%, and the illuminance was 180W / m 2 Under the condition of UV irradiation (wavelength range: 300-400 nm), a solar cell backsheet test piece of 10 cm x 20 cm was repeatedly irradiated with UV rays for 108 minutes and then irradiated with UV rays while spraying water for 12 minutes (without humidity control) for a total of 3000 hours. The test piece was then cut into a size of 1 cm x 10 cm, and the breaking elongation was measured by the above method, and the result was defined as the breaking elongation after aging Ee.

[0301] -Weather resistance evaluation- As an index of weather resistance, the breaking elongation retention rate (%)=(Ee / Es)×100 was calculated, and the weather resistance was evaluated as follows based on the following evaluation criteria. [Evaluation Criteria] A: Breaking elongation retention is 50% or more B: Breaking elongation retention rate is 30% or more and less than 50% C: Breaking elongation retention is less than 30%

[0302] The weather resistance results of the solar cell backsheets BS-1 to BS-4 of Examples 109 to 112 and the comparative solar cell backsheets RBS1 to RBS2 of Comparative Examples 30 to 31 are summarized in Table 10.

[0303] [Table 10]

[0304] For example, aspects of the present invention are as follows. <1> The copolymer is characterized by having a structural unit represented by the following general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group. [ka] (In the general formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group, "CH2=CH-COO-", or "CH2=C(CH3)-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.) <2> 1. An ink comprising water, a colorant, and a copolymer, The copolymer is an ink characterized by having a structural unit represented by the following general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group. [ka] (In the general formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group, "CH2=CH-COO-", or "CH2=C(CH3)-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.) <3> The structural unit having a naphthyl group and / or a pyridyl group is represented by the following general formula (2): <2> The ink is as described in [ka] (In the general formula (2), R3 represents hydrogen or a methyl group, L1 represents "-COO- (bonded to X)", "-CONH- (bonded to X)", or a bond, X represents a hydrocarbon group having 2 to 10 carbon atoms or a hydrocarbon group containing oxygen and having 2 to 10 carbon atoms, L2 represents "-O-" or "-NH-", Y represents a hydrocarbon group having 2 to 12 carbon atoms or a bond, L3 represents "-NHCO- (bonded to Z)", "-OCO- (bonded to Z)", "-O-", or "-(CH2)n-", n represents an integer of 1 to 3, and Z represents a naphthyl group or a pyridyl group.) <4> The weight average molecular weight of the copolymer is 5,000 or more and 50,000 or less. <2> or the above <3> The ink is as described in <5> The coloring material is titanium oxide. <2> From the above <4> The ink according to any one of claims 1 to 5, <6> The above <2> From the above <5> 1 is an ink container that contains the ink according to any one of the above items. <7> The above <2> From the above <5> 2. An image forming method comprising discharging the ink according to any one of claims 1 to 11 onto a recording medium to form an image. <8> The above <2> From the above <5> an ink container that contains the ink according to any one of the preceding claims; a discharge means for discharging the ink contained in the ink container onto a recording medium; The image forming apparatus is characterized by comprising: <9> A solar cell backsheet having a protective layer, The protective layer is <2> From the above <5> 2. A solar cell back sheet comprising a coating film made of the ink according to any one of claims 1 to 11.

[0305] The above <1> From the above <5> The ink according to any one of the preceding claims. <6> The ink container according to the <7> The image forming method according to the <8> and the image forming apparatus according to the above. <9> According to the solar cell backsheet described above, the conventional problems can be solved and the object of the present invention can be achieved. [Explanation of symbols]

[0306] 400 Image forming device 401 Exterior of image forming device 401c Device body cover 404 Cartridge Holder 410 Main Tank 410k, 410c, 410m, 410y, 410w Main tanks for each color: Black (K), Cyan (C), Magenta (M), Yellow (Y), and White (W) 411 Ink storage unit 413 Ink outlet 414 Storage container case 420 Mechanism Department 434 Discharge Head 436 Supply Tube [Prior art documents] [Patent documents]

[0307] [Patent Document 1] Patent No. 5863600

Claims

1. A copolymer comprising a structural unit represented by the following general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group: 【Chemistry 1】 (In the general formula (1), R １ represents hydrogen or a methyl group, R ２ is a methyl group, "CH ２ =CH-COO-" or "CH ２ = C(CH ３ )-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.

2. 1. An ink comprising water, a colorant, and a copolymer, The copolymer is characterized in that it has a structural unit represented by the following general formula (1), a structural unit having an anionic group, and a structural unit having a naphthyl group and / or a pyridyl group. 【Chemistry 2】 (In the general formula (1), R １ represents hydrogen or a methyl group, R ２ is a methyl group, "CH ２ =CH-COO-" or "CH ２ = C(CH ３ )-COO-", and n is an integer such that the weight average molecular weight of the structural unit represented by the general formula (1) is 420 or more and 120,000 or less.

3. The ink according to claim 2 , wherein the structural unit having a naphthyl group and / or a pyridyl group is represented by the following general formula (2): 【Chemistry 3】 (In general formula (2), R ３ represents hydrogen or a methyl group; L １ represents "-COO- (bonded to X)", "-CONH- (bonded to X)", or a bond, X represents a hydrocarbon group having 2 to 10 carbon atoms, or a hydrocarbon group containing oxygen having 2 to 10 carbon atoms, L ２ represents "-O-" or "-NH-", Y represents a hydrocarbon group having 2 to 12 carbon atoms or a bond, L ３ is "-NHCO- (bonded to Z)", "-OCO- (bonded to Z)", "-O-" or "-(CH ２ ) n-", n is an integer of 1 to 3, and Z is a naphthyl group or a pyridyl group.

4. The ink according to claim 2 or 3, wherein the weight average molecular weight of the copolymer is from 5,000 to 50,000.

5. The ink according to claim 2 or 3, wherein the coloring material is titanium oxide.

6. An ink container comprising the ink according to claim 2 or 3.

7. 4. An image forming method comprising discharging the ink according to claim 2 or 3 onto a recording medium to form an image.

8. an ink container that contains the ink according to claim 2 or 3; a discharge means for discharging the ink contained in the ink container onto a recording medium; An image forming apparatus comprising:

9. A solar cell backsheet having a protective layer, A solar cell backsheet, wherein the protective layer is a coating film made of the ink according to claim 2 or 3.

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