WO2022107402A1 - (meth)acrylic copolymer, (meth)acrylic copolymer composition, and ink - Google Patents

(meth)acrylic copolymer, (meth)acrylic copolymer composition, and ink Download PDF

Info

Publication number
WO2022107402A1
WO2022107402A1 PCT/JP2021/029243 JP2021029243W WO2022107402A1 WO 2022107402 A1 WO2022107402 A1 WO 2022107402A1 JP 2021029243 W JP2021029243 W JP 2021029243W WO 2022107402 A1 WO2022107402 A1 WO 2022107402A1
Authority
WO
WIPO (PCT)
Prior art keywords
meth
acrylic copolymer
mercaptan
derived
ink
Prior art date
Application number
PCT/JP2021/029243
Other languages
French (fr)
Japanese (ja)
Inventor
倫仁 小林
Original Assignee
三菱ケミカル株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱ケミカル株式会社 filed Critical 三菱ケミカル株式会社
Priority to CN202180067390.2A priority Critical patent/CN116390960A/en
Priority to JP2022563580A priority patent/JPWO2022107402A1/ja
Publication of WO2022107402A1 publication Critical patent/WO2022107402A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/02—Printing inks
    • C09D11/10—Printing inks based on artificial resins
    • C09D11/106—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

  • the present invention relates to (meth) acrylic copolymers, (meth) acrylic copolymer compositions and inks.
  • water-based inks can reduce the amount of volatile organic compounds (VOCs), and can reduce the risk of fire and toxicity such as mutagenicity. Therefore, water-based inks are widely used in applications such as gravure printing.
  • VOCs volatile organic compounds
  • acrylic polymers and (meth) acrylic copolymers containing (meth) acrylic acid alkyl ester-derived structural units and (meth) acrylic acid-derived structural units have high transparency and pigments. Because of its good color development, it is widely used in water-based ink applications.
  • the (meth) acrylic polymer and (meth) acrylic copolymer for water-based inks have good solubility in alkaline water, the total amount of VOC at the time of dissolution can be suppressed to a small level, and the storage stability of the ink is stable. Good properties and good concealment during film printing are required.
  • Patent Document 1 a polycarboxylic acid resin and a polyol resin produced by solution polymerization using polyfunctional mercaptan are condensed in a solvent different from the polymerization solvent, and then neutralized with an amine at 95 ° C.
  • Patent Document 2 describes a method for obtaining an aqueous pigment dispersion having high storage stability by introducing a hydrophobic moiety and a hydrophilic moiety into a polyfunctional mercaptan prepared in a solution.
  • the present invention includes a (meth) acrylic copolymer having good solubility in alkaline water, good storage stability of ink, and good concealment in film printing; the above-mentioned (meth) acrylic copolymer ( It is an object of the present invention to provide an ink containing a (meth) acrylic copolymer composition; and the (meth) acrylic copolymer composition.
  • the present invention has the following aspects.
  • It has a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, a structural unit derived from an acid group-containing vinyl compound, and a chemical structure derived from a trifunctional or higher functional mercaptan.
  • it is a (meth) acrylic copolymer that is a solid in the form of particles.
  • It has a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, a structural unit derived from an acid group-containing vinyl compound, and a chemical structure derived from trifunctional or higher mercaptan.
  • a (meth) acrylic copolymer further comprising one or more chemical structures selected from the group consisting of monofunctional mercaptan-derived chemical structures and bifunctional mercaptan-derived chemical structures.
  • (Meta) acrylic copolymer [6] The (meth) acrylic copolymer according to any one of [1] to [5], wherein the (meth) acrylic copolymer has a mass average particle size of 20 to 2000 ⁇ m. [7] The (meth) acrylic copolymer according to any one of [1] to [6], wherein the (meth) acrylic copolymer has a water content of 0.01 to 10% by mass.
  • the (meth) acrylic copolymer and the (meth) acrylic copolymer having good solubility in alkaline water and good storage stability of ink and good concealment in film printing can be obtained. It is possible to provide an ink containing the (meth) acrylic copolymer composition containing the (meth) acrylic copolymer composition and the (meth) acrylic copolymer composition.
  • (meth) acrylic acid is a general term for acrylic acid and methacrylic acid.
  • (Meta) acrylic is a general term for acrylic and methacrylic.
  • the "(meth) acrylic copolymer” is, for example, a copolymer having at least one of an acryloyl group and a methacryloyl group.
  • (meth) acrylate is a general term for acrylate and methacrylate.
  • the ratio of each structural unit of the (meth) acrylic copolymer and the ratio of the chemical structure derived from mercaptan mean those calculated from the mass ratio of each monomer used as the polymerization raw material and mercaptan. ..
  • the term “room temperature” means a temperature within the range of 23 ° C. ⁇ 2 ° C. unless otherwise specified.
  • the (meth) acrylic copolymer according to the first aspect of the present invention is also referred to as a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (hereinafter, also referred to as “monomer (a)”. ), A structural unit derived from an acid group-containing vinyl compound (hereinafter, also referred to as “monomer (b)”), and a chemical structure derived from a trifunctional or higher functional mercaptan.
  • the (meth) acrylic copolymer of the first aspect further preferably has one or more chemical structures selected from the group consisting of a monofunctional mercaptan-derived chemical structure and a bifunctional mercaptan-derived chemical structure. .. Further, the (meth) acrylic copolymer has a structure derived from a monomer other than the monomer (a) and the monomer (b) (hereinafter, also referred to as “monomer (c)”). It may have more units.
  • the (meth) acrylic copolymer of the second aspect of the present invention has a structural unit derived from the monomer (a), a structural unit derived from the monomer (b), and a chemistry derived from trifunctional or higher functional mercaptan. It has a structure and further has one or more chemical structures selected from the group consisting of a monofunctional mercaptan-derived chemical structure and a bifunctional mercaptan-derived chemical structure. Further, the (meth) acrylic copolymer of the second aspect may further have a structural unit derived from the monomer (c).
  • the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention is a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, that is, a single amount. It has a structural unit derived from the body (a).
  • Examples of the monomer (a) in the (meth) acrylic copolymer of the first aspect and the second aspect include methyl (meth) acrylate, ethyl (meth) acrylate, and n- (meth) acrylate.
  • Examples thereof include hexyl, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate.
  • methyl (meth) acrylate, n-butyl (meth) acrylate, and acrylic acid are available because the (meth) acrylic copolymer has better solubility in alkaline water and is easily available.
  • 2-Ethylhexyl is preferred. These may be used alone or in combination of two or more.
  • the proportion of the structural unit derived from the monomer (a) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b).
  • the structural unit derived from the monomer (a) and the monomer (b) are the structural unit derived from the monomer (a) and the monomer (b).
  • 60 to 97% by mass is preferable, and 80 to 95% by mass is more preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the ratio of the structural unit derived from the monomer (a) is within the above range, the film forming property and the water resistance of the ink are good.
  • the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention has a structural unit derived from an acid group-containing vinyl compound, that is, a structural unit derived from the monomer (b).
  • the monomer (b) include vinyl compounds having an acid group such as carboxylic acid or sulfonic acid.
  • Specific examples of the vinyl compound having a carboxylic acid group in the (meth) acrylic copolymer of the first aspect and the second aspect include monobasic acids such as (meth) acrylic acid and crotonic acid; fumaric acid and malein. Bibasic acids such as acids and itaconic acids; partial esters of these dibasic acids and the like can be mentioned.
  • vinyl compound having a sulfonic acid group examples include vinyl sulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and the like.
  • a vinyl compound having a carboxylic acid group is preferable, and (meth) acrylic acid is more preferable, from the viewpoint of improving the water solubility of the (meth) acrylic copolymer.
  • These may be used alone or in combination of two or more.
  • the proportion of the structural unit derived from the monomer (b) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b).
  • the structural unit derived from the monomer (a) and the monomer (b) Of the total 100% by mass of the derived constituent units, 3 to 40% by mass is preferable, and 5 to 20% by mass is more preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the ratio of the structural unit derived from the monomer (b) is within the above range, the solubility of the (meth) acrylic copolymer in alkaline water and the solubility in other solvents are better.
  • the total ratio of the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b) in the (meth) acrylic copolymer of the first aspect and the second aspect is the (meth) acrylic system. 70 to 99.9% by mass is preferable, 80 to 99% by mass is more preferable, and 85 to 95% by mass is further preferable with respect to the total mass of all the constituent units constituting the copolymer.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the total ratio of the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b) is within the above range, the solubility in alkaline water is extremely good.
  • the total mass of all the structural units constituting the (meth) acrylic copolymer of the first aspect and the second aspect also includes the ratio of the chemical structure derived from metacaptan, which will be described later.
  • the (meth) acrylic copolymer of the first aspect and the second aspect has a chemical structure derived from a trifunctional or higher functional mercaptan.
  • a trifunctional or higher functional mercaptan as a chain transfer agent in the polymerization reaction when producing the (meth) acrylic copolymer of the first aspect and the second aspect, the trifunctional or higher functionality is used.
  • the mercaptan of the above becomes the starting point of the polymerization, and the chemical structure derived from the trifunctional or higher mercaptan is introduced into the (meth) acrylic copolymer.
  • a trifunctional or higher functional mercaptan is a compound having three or more mercapto groups in a single molecule.
  • Examples of the trifunctional or higher functional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect include 1,2,3-trimercaptopropane and 2,2-bis (mercaptomethyl) -1-.
  • trimethylol propanthris (3-mercaptopropionate) and pentaerythritol tetrakis (3) are available because the (meth) acrylic copolymer has better solubility in alkaline water and is easily available.
  • -Mercaptopropionate pentaerythritol tetrakis (thioglycolate) are preferred. These may be used alone or in combination of two or more.
  • the proportion of the chemical structure derived from the trifunctional or higher mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect is derived from all the monomers constituting the (meth) acrylic copolymer. 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the constituent units.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the proportion of the chemical structure derived from the trifunctional or higher mercaptan is at least the above lower limit, the solubility of the (meth) acrylic copolymer in alkaline water tends to be better.
  • the ratio of the chemical structure derived from the trifunctional or higher mercaptan is not more than the above upper limit value, the odor of the (meth) acrylic copolymer is suppressed.
  • the (meth) acrylic copolymer of the first aspect is selected from the group consisting of a chemical structure derived from a trifunctional or higher functional mercaptan, a chemical structure derived from a monofunctional mercaptan, and a chemical structure derived from a bifunctional mercaptan. It is preferable to further have one or more chemical structures. If the (meth) acrylic copolymer of the first aspect further has one or more chemical structures selected from the group consisting of monofunctional mercaptan-derived chemical structures and bifunctional mercaptan-derived chemical structures, alkaline water. The viscosity at the time of dissolution in is lowered, and it becomes easy to mix pigments and the like.
  • the (meth) acrylic copolymer of the second aspect has a chemical structure derived from a trifunctional or higher mercaptan, a chemical structure derived from a trifunctional or higher mercaptan, and a chemical structure derived from a monofunctional mercaptan. It further has one or more chemical structures selected from the group consisting of bifunctional mercaptan-derived chemical structures. Therefore, according to the (meth) acrylic copolymer of the second aspect, the viscosity at the time of dissolution in alkaline water becomes low, and the compounding of a pigment or the like becomes easy.
  • a monofunctional mercaptan is a compound having one mercapto group in a single molecule.
  • Examples of the monofunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, and thioglycolic acid.
  • the proportion of the chemical structure derived from the monofunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect is the composition derived from all the monomers constituting the (meth) acrylic copolymer. 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the unit.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the ratio of the chemical structure derived from the monofunctional mercaptan is at least the above lower limit, the solubility of the (meth) acrylic copolymer in alkaline water tends to be better.
  • the ratio of the chemical structure derived from the monofunctional mercaptan is not more than the above upper limit value, the odor of the (meth) acrylic copolymer is suppressed.
  • a bifunctional mercaptan is a compound having two mercapto groups in a single molecule.
  • the bifunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect include 1,4-dimercaptobutane, 3-oxo-1,5-pentanedithiol, and 3-thia-. Examples thereof include 1,5-pentanedithiol, ethylene glycol bis (3-mercaptopropionate), and 1,4-butanediol bis (thioglycolate). These may be used alone or in combination of two or more.
  • the proportion of the chemical structure derived from the bifunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect is the composition derived from all the monomers constituting the (meth) acrylic copolymer. 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the unit.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the ratio of the chemical structure derived from the bifunctional mercaptan is at least the above lower limit, the solubility of the (meth) acrylic copolymer in alkaline water tends to be better.
  • the ratio of the chemical structure derived from the bifunctional mercaptan is not more than the above upper limit value, the odor of the (meth) acrylic copolymer is suppressed.
  • the (meth) acrylic copolymer of the first aspect and the second aspect is a structural unit derived from the monomer (a) and a structural unit derived from the monomer (b), as well as other monomers. It may further have a structural unit derived from (monomer (c)).
  • the monomer (c) in the (meth) acrylic copolymer of the first aspect and the second aspect is also referred to as a compound having one polymerizable double bond (hereinafter, “monomer (c1)”). ), Compounds having two or more polymerizable double bonds (hereinafter, also referred to as “monomer (c2)”) and the like can be mentioned.
  • the monomer (c2) is preferable as the monomer (c). That is, the (meth) acrylic copolymer further has a structural unit derived from the monomer (c2) in addition to the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b). Is preferable.
  • Examples of the monomer (c1) in the (meth) acrylic copolymer of the first aspect and the second aspect include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and ⁇ -methylstyrene.
  • the proportion of the structural unit derived from the monomer (c1) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b). 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the derived constituent units.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the ratio of the structural unit derived from the monomer (c1) is at least the above lower limit value, the storage stability of the ink tends to be better.
  • the ratio of the structural unit derived from the monomer (c1) is not more than the above upper limit value, the viscosity of the ink can be lowered and the handling at the time of printing becomes good.
  • Examples of the monomer (c2) in the (meth) acrylic copolymer of the first aspect and the second aspect include ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, and 1 , 4-Butandiol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanedimethanol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) ) Acrylate, 1,3-propylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, bisphenol A-di (meth) acrylate, 2,2-
  • ethylene glycol diacrylate, 1,6-hexanediol di (meth) acrylate, and trimethylolpropane tri (meth) are low in viscosity when dissolved in alkaline water and can be easily blended with pigments.
  • Acrylate is preferred. These may be used alone or in combination of two or more.
  • the proportion of the structural unit derived from the monomer (c2) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b). 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the derived constituent units.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the ratio of the structural unit derived from the monomer (c2) is at least the above lower limit value, the storage stability of the ink tends to be better.
  • the ratio of the structural unit derived from the monomer (c2) is not more than the above upper limit value, the viscosity of the ink can be lowered and the handling at the time of printing becomes good.
  • the (meth) acrylic copolymer of the first aspect is solid at room temperature. Since the (meth) acrylic copolymer of the first aspect is solid at room temperature, VOC when dissolved in alkaline water can be reduced. In addition, it is suitable for transportation and storage because it can suppress the increase in volume as compared with the state of being dissolved in water (aqueous solution) and the state of being dispersed in water (dispersion liquid).
  • the (meth) acrylic copolymer of the second aspect is also preferably solid at room temperature. When the (meth) acrylic copolymer of the second aspect is solid at room temperature, VOC when dissolved in alkaline water can be reduced.
  • the solid (meth) acrylic copolymer includes powder-like, plate-like, crushed-like, spherical, particle-like, granular, and pellet-like solids. Among these, powdery, crushed, spherical, particulate, and granular solids are preferable because they are easy to handle when dissolved in a solvent or alkaline water.
  • the (meth) acrylic copolymer of the first aspect and the second aspect can be easily dissolved in water or a mixed solvent of water and an auxiliary solvent described later by neutralizing with a basic compound described later. ..
  • the secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 35 ° C. or higher, more preferably 40 ° C. or higher, still more preferably 45 ° C. or higher.
  • the secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 70 ° C. or lower, more preferably 60 ° C. or lower, still more preferably 55 ° C. or lower.
  • the secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect can be measured using a differential scanning calorimeter (DSC), and the specific measurement thereof. The method is as described in the section of Examples.
  • the mass average particle size of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 20 to 2000 ⁇ m, more preferably 50 to 850 ⁇ m, further preferably 80 to 700 ⁇ m, and particularly preferably 150 to 600 ⁇ m. preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the mass average particle size of the (meth) acrylic copolymer is at least the above lower limit, the compounding work becomes easy. Further, when the mass average particle size of the (meth) acrylic copolymer is not more than the above upper limit value, the dissolution time in alkaline water is shortened.
  • the mass average particle size of the (meth) acrylic copolymer can be calculated by shaking 20 g of the granular resin for 5 minutes using a standard sieve to classify the (meth) acrylic copolymer.
  • the water content of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 0.01 to 10% by mass, and 0.02 to 8. 0% by mass is more preferable, 0.1 to 5.0% by mass is further preferable, and 0.5 to 5.0% by mass is particularly preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily. When the water content of the (meth) acrylic copolymer is at least the above lower limit, the solubility in alkaline water is good. Further, when the water content of the (meth) acrylic copolymer is not more than the above upper limit value, the water resistance of the printed matter is high.
  • the handleability of the copolymer when the particulate (meth) acrylic copolymer is obtained is good.
  • the specific method for measuring the water content of the (meth) acrylic copolymer is as described in the section of Examples.
  • the acid value of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 20 to 140 mgKOH / g, more preferably 50 to 100 mgKOH / g, still more preferably 55 to 90 mgKOH / g.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the acid value of the (meth) acrylic copolymer is at least the above lower limit, the solubility in alkaline water becomes better.
  • the acid value of the (meth) acrylic copolymer is not more than the above upper limit, the amount of the basic compound required for neutralization and dissolution can be reduced, and the water resistance of the printed matter is also good.
  • the acid value of the (meth) acrylic copolymer means a value expressed in milligrams of the mass of potassium hydroxide required to neutralize 1 g of the (meth) acrylic copolymer.
  • the acid value of the (meth) acrylic copolymer of the first aspect and the second aspect can be measured by neutralization titration with a potassium hydroxide solution based on the discoloration point of phenolphthalein. The specific measurement method is as described in the section of Examples.
  • the weight average molecular weight (Mw) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 15,000 to 80,000, more preferably 15,000 to 60,000, further preferably 20,000 to 60,000, and even more preferably 25,000 to 60,000. Is particularly preferable, and 25,000 to 40,000 is most preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily. When the weight average molecular weight of the (meth) acrylic copolymer is at least the above lower limit, the storage stability of the ink tends to be better.
  • the weight average molecular weight (Mw) of the (meth) acrylic copolymer of the first aspect and the second aspect is the weight average molecular weight (in terms of polystyrene) measured by gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • the number average molecular weight (Mn) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 5000 to 120000, more preferably 8000 to 80000, still more preferably 12000 to 70000. 15,000 to 60,000 is particularly preferable, and 20,000 to 50,000 is most preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the number average molecular weight of the (meth) acrylic copolymer is at least the above lower limit, the storage stability of the ink tends to be better.
  • the number average molecular weight of the (meth) acrylic copolymer is not more than the above upper limit, the viscosity of the ink tends to be low and the film forming property tends to be good.
  • the number average molecular weight (Mn) of the (meth) acrylic copolymer of the first aspect and the second aspect is the number average molecular weight (in terms of polystyrene) measured by gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • the (meth) acrylic copolymer of the first aspect and the second aspect can be produced by a known polymerization method such as bulk polymerization, suspension polymerization and emulsion polymerization.
  • a known polymerization method such as bulk polymerization, suspension polymerization and emulsion polymerization.
  • bulk polymerization and suspension polymerization are preferable from the viewpoint that a powder-like polymer, a spherical or particle-like copolymer, which is easy to handle, can be easily obtained.
  • the method for producing the (meth) acrylic copolymer according to the first aspect and the second aspect by suspension polymerization includes a suspension polymerization step, a first dehydration step, a washing step, and a second dehydration step. , It is preferable to have a drying step.
  • suspension polymerization step In the suspension polymerization step, the above-mentioned monomers (a) and (b) and, if necessary, the monomer (c) are dispersed in water and polymerized in the presence of trifunctional or higher mercaptan. This is a step of obtaining the (meth) acrylic copolymer of the first aspect and the second aspect.
  • a known method can be adopted as the method of suspension polymerization.
  • Examples of the polymerization aid that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect include a polymerization initiator, a chain transfer agent, a dispersant, and a dispersion aid.
  • a polymerization initiator e.g., ethylene glycol dimethacrylate
  • a chain transfer agent e.g., ethylene glycol dimethacrylate
  • a dispersant e.g., a dispersant, and a dispersion aid.
  • Examples of the polymerization initiator that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect include 2,2'-azobisisobutyronitrile and 2,2'-azobis (2). -Methylbutyronitrile), benzoyl peroxide, lauroyl peroxide, tert-butylperoxy-2-ethylhexanoate, tert-amylhydroxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexanoate , 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate and the like. These may be used alone or in combination of two or more.
  • a mercaptan having at least trifunctionality or higher is used as the chain transfer agent.
  • the chain transfer agent in addition to the trifunctional or higher functional mercaptan, at least one of the above-mentioned monofunctional mercaptan and bifunctional mercaptan may be used in combination.
  • diphenyl disulfide, dibenzyl disulfide, and ⁇ -methylstyrene dimer may be further used in combination. These may be used alone or in combination of two or more.
  • Examples of the dispersant that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect include a surfactant that stably disperses the monomer in water.
  • Examples thereof include copolymers, polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose and the like. These may be used alone or in combination of two or more.
  • Dispersing aids that can be used in the production of the (meth) acrylic copolymers of the first and second aspects include, for example, sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium chloride. , Calcium acetate, magnesium sulfate, manganese sulfate and the like. These may be used alone or in combination of two or more.
  • the (meth) acrylic copolymer of the first aspect and the second aspect is obtained in the state of a slurry.
  • (meth) acrylic copolymer particles having a shape close to that of a true sphere can be obtained.
  • the first dehydration step is a step of dehydrating the slurry after suspension polymerization with a dehydrator or the like to separate the (meth) acrylic copolymer particles of the first aspect and the second aspect from the reaction solution.
  • the second dehydration step is a step of dehydrating the (meth) acrylic copolymer particles after the washing step with a dehydrator or the like to separate the (meth) acrylic copolymer particles from the washing liquid.
  • Various dehydrators can be used in each dehydration step, and for example, a centrifugal dehydrator, a device having a mechanism for sucking and removing water on a perforated belt, and the like can be appropriately selected and used.
  • a centrifugal dehydrator a device having a mechanism for sucking and removing water on a perforated belt, and the like can be appropriately selected and used.
  • One dehydrator may be used, two dehydrators of the same model may be prepared and used in each dehydration step, or a plurality of different models of dehydrators may be used. It is possible to appropriately select a model that suits the purpose in terms of product quality, capital investment cost, productivity, operating cost, and the like. When the balance between product quality and production speed is important, it is preferable to use a dedicated dehydrator in each dehydration process.
  • the washing step is to wash the (meth) acrylic copolymer particles separated from the reaction solution.
  • a cleaning method for example, a method of adding a cleaning liquid to the (meth) acrylic copolymer particles dehydrated in the first dehydration step to re-slurry the (meth) acrylic copolymer and stirring and mixing the (meth) acrylic copolymer, and a cleaning function.
  • a cleaning liquid for example, a method of adding a cleaning liquid to the (meth) acrylic copolymer particles dehydrated in the first dehydration step to re-slurry the (meth) acrylic copolymer and stirring and mixing the (meth) acrylic copolymer, and a cleaning function.
  • the type and amount of cleaning liquid may be selected so that the purpose of the cleaning process is achieved.
  • the cleaning liquid include water (ion-exchanged water, distilled water, purified water, etc.), an aqueous solution in which a sodium salt is dissolved, a buffer adjusted to an arbitrary pH, methanol, and the like.
  • the drying step is a step of drying the (meth) acrylic copolymer particles of the first aspect and the second aspect after the second dehydration step. Water remains on the surface of the (meth) acrylic copolymer particles after the second dehydration step. Further, the inside of the (meth) acrylic copolymer is in a state close to saturated water absorption. Therefore, in order to further reduce the water content of the (meth) acrylic copolymer of the first aspect and the second aspect, it is preferable to dry.
  • a dryer that heats under reduced pressure to dry, and (meth) acrylic copolymer particles are simultaneously dried while being air-transported in a tube using warm air.
  • a dryer that performs drying while blowing warm air from the lower side of the perforated plate and flowing the (meth) acrylic copolymer particles on the upper side.
  • the drying step is preferably performed so that the water content of the (meth) acrylic copolymer of the first aspect and the second aspect after the drying step is 0.01 to 10% by mass.
  • the method for producing a (meth) acrylic copolymer by bulk polymerization preferably includes a bulk polymerization step and a pulverization step.
  • a devolatile step may be provided between the bulk polymerization step and the pulverization step.
  • the above-mentioned monomers (a) and (b) and, if necessary, the monomer (c) are polymerized in the presence of trifunctional or higher functional mercaptan, and the first embodiment is carried out. And the step of obtaining the (meth) acrylic copolymer of the second aspect.
  • a known method can be adopted as the bulk polymerization method.
  • the monomer (a) and the monomer (b) and, if necessary, the monomer (c) are polymerized in a reactor having a polymerization temperature control function. Examples thereof include a method of polymerizing in the presence of an auxiliary agent.
  • Examples of the polymerization aid include a polymerization initiator and a chain transfer agent. However, at least the above-mentioned trifunctional or higher functional mercaptan is used as the chain transfer agent.
  • Examples of the polymerization initiator include the polymerization initiator exemplified above in the description of the suspension polymerization step.
  • Examples of the chain transfer agent include the chain transfer agents exemplified above in the description of the suspension polymerization step.
  • the shape of the reactor used in the bulk polymerization step is arbitrary.
  • a glass cell in which a rubber tube having both ends connected to form an annular shape is sandwiched between two tempered glass plates and the four corners are clipped can be used as a reactor.
  • examples of the reactor used industrially include a closed container having a stirring mechanism.
  • the polymerization temperature control function for example, when the glass cell is used as a reactor, a commercially available constant temperature water tank may be used.
  • a closed container having a stirring mechanism When a closed container having a stirring mechanism is used, the temperature can be controlled by exchanging heat with a heat medium or a refrigerant whose temperature has been adjusted from the outer surface of the reaction container.
  • the devolatile step removes volatile components (for example, unreacted monomer, water, etc.) contained in the (meth) acrylic copolymer of the first aspect and the second aspect obtained in the bulk polymerization step (for example, unreacted monomer, moisture, etc.). This is the process of devolatile).
  • a known method can be adopted as the devolatilization method.
  • Examples of the devolatile method include a method of treating a (meth) acrylic copolymer using an extruder with a vent. The set temperature of the extruder may be determined in consideration of the boiling point of the volatile component to be removed and the like.
  • the pulverization step is a step of pulverizing the (meth) acrylic copolymer of the first aspect and the second aspect, which have been devolatile-treated as necessary, so as to have a desired particle size.
  • the pulverization method any pulverization method according to the required particle size can be adopted.
  • the maximum diameter of the particles after pulverization is preferably 5 mm or less, more preferably 2 mm or less, from the viewpoint of forming a slurry with water during neutralization and dissolution in water.
  • the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention described above has excellent solubility and powder properties, it has good solubility in various solvents, especially alkaline water. be. Further, the composition and the ink containing the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention are excellent in coatability, storage stability and concealment in film printing. Therefore, it is unlikely that bumps or uneven printing will occur during printing. Further, the (meth) acrylic copolymer according to the first aspect and the second aspect of the present invention is also excellent in productivity.
  • the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention can be used as a raw material for, for example, inks and paints. In particular, it is suitable as a raw material for water-based inks.
  • the (meth) acrylic copolymer composition of the present invention is a group consisting of the (meth) acrylic copolymer of the first aspect of the present invention and the (meth) acrylic copolymer of the second aspect described above. Containing one or more selected from; with water; with a basic compound;
  • the (meth) acrylic copolymer composition may further contain a pigment and a solvent other than water (hereinafter, also referred to as "auxiliary solvent").
  • auxiliary solvent a solvent other than water
  • the (meth) acrylic copolymer composition containing a pigment is also particularly referred to as a “pigment-containing composition”.
  • the content of the (meth) acrylic copolymer is preferably 10 to 60% by mass, more preferably 15 to 50% by mass, based on the total mass of the (meth) acrylic copolymer composition.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the (meth) acrylic copolymer is at least the above lower limit value, the film-forming property is good and the texture at the time of printing on the substrate is good.
  • the content of the (meth) acrylic copolymer is not more than the above upper limit value, the film-forming property is good and good printing performance on various substrates is exhibited.
  • the water content is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, based on the total mass of the (meth) acrylic copolymer composition.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily. When the water content is at least the above lower limit, the miscibility with the pigment is good. When the water content is not more than the above upper limit, the viscosity after dissolving the (meth) acrylic polymer is low, and the mixing property with other materials is good.
  • the basic compound serves to neutralize the solid (meth) acrylic copolymer and dissolve it in water or a mixed solvent of water and an auxiliary solvent.
  • the basic compound include alkali metal hydroxides, ammonia, aqueous ammonia, and amine compounds.
  • alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like.
  • the amine compound include triethylamine, 1-propylamine, diethylamine, triisopropylamine, dibutylamine, amylamine, 1-octylamine, 2- (dimethylamino) ethanol, 2- (ethylamino) ethanol and 2- (diethylamino).
  • Ethanol 1-amino-2-propanol, 2-amino-1-propanol, 3-amino-1-propanol, 1- (dimethylamino) -2-propanol, 3- (dimethylamino) -1-propanol, 2- Examples thereof include (propylamino) ethanol, bis (3-ethoxypropyl) amine, aminobenzyl alcohol, morpholin, N-methylmorpholin, tetrabutylammonium hydroxide and the like.
  • the amine valence per usage amount is high, the amount of amine required for neutralization can be reduced, the ink can be made low in VOC, and the printed matter is easily volatilized after drying and does not easily remain in the printed matter.
  • Triethylamine, 2- (dimethylamino) ethanol are preferred. These may be used alone or in combination of two or more.
  • the content of the basic compound is preferably 0.1 to 10% by mass, more preferably 2 to 5% by mass, based on the total mass of the (meth) acrylic copolymer composition.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the basic compound is at least the above lower limit, the solubility of the (meth) acrylic polymer composition is good.
  • the content of the basic compound is not more than the above upper limit value, the water resistance after printing is good.
  • pigment examples include titanium oxide, carbon black, phthalocyanine blue, phthalocyanine green, chrome yellow, cadmium yellow, chrome yellow, cobalt blue, chrome green, cobalt green, benzidine yellow, and zinc white.
  • any commercially available pigment can also be used. These may be used alone or in combination of two or more.
  • the content of the pigment is preferably 20 to 60% by mass, preferably 20 to 50% by mass, based on the total mass of the (meth) acrylic copolymer composition. % Is more preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the pigment is at least the above lower limit value, the concealment property to the substrate is improved and the color development of the coating film is improved.
  • the content of the pigment is not more than the above upper limit value, the ink in which the pigment is uniformly dispersed can be adjusted, and the coating film has less lumps.
  • the (meth) acrylic copolymer composition of the present invention contains water as a solvent, but may contain a solvent other than water as an auxiliary solvent, if necessary.
  • auxiliary solvent include water-soluble organic solvents among alcohols, glycols, ethers, ketones, esters, and carbitols. These may be used alone or in combination of two or more.
  • the content of the auxiliary solvent is preferably 1 to 40% by mass, preferably 2 to 40% by mass, based on the total mass of the (meth) acrylic copolymer composition. 30% by mass is more preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the auxiliary solvent is at least the above lower limit value, the leveling property in the (meth) acrylic copolymer composition can be further improved.
  • the content of the auxiliary solvent is not more than the above upper limit value, the amount of the volatile organic compound (VOC) contained in the (meth) acrylic copolymer composition can be reduced.
  • the (meth) acrylic copolymer composition is obtained by dissolving the (meth) acrylic copolymer together with a basic compound in, for example, water or a mixed solvent of water and an auxiliary solvent. At that time, a pigment may be blended if necessary.
  • Specific examples of the production method include a method of mixing and stirring the components constituting the (meth) acrylic copolymer composition using a normally used stirrer.
  • the (meth) acrylic copolymer composition of the present invention described above is excellent in coatability, storage stability and concealment in film printing, and thus is less likely to cause bumps and uneven printing during printing.
  • the ink of the present invention contains the above-mentioned (meth) acrylic copolymer composition.
  • the ink further contains a pigment in addition to the (meth) acrylic copolymer composition.
  • the pigment-containing composition itself may be used as an ink, or may be further diluted with water or an auxiliary solvent.
  • the ink may further contain an auxiliary solvent, a binder, other auxiliary agents and the like, if necessary, for various purposes.
  • the content of the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention contained in the ink is preferably 5 to 30% by mass, preferably 10 to 25% by mass, based on the total mass of the ink. Is more preferable.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the (meth) acrylic copolymer is at least the above lower limit value, aggregation of the primary particles of the pigment can be suppressed.
  • the content of the (meth) acrylic copolymer is not more than the above upper limit value, the ink has a low viscosity and is easy to handle.
  • the content of water contained in the ink is preferably 20 to 60% by mass, more preferably 25 to 50% by mass, based on the total mass of the ink.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the water content is at least the above lower limit value, the ink has a low viscosity and is easy to print.
  • the water content is not more than the above upper limit value, the dryness of the printed matter is good.
  • the content of the basic compound contained in the ink is preferably 0.1 to 10% by mass, more preferably 2 to 5% by mass, based on the total mass of the ink.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the basic compound is at least the above lower limit value, the film forming property of the ink is good.
  • the content of the basic compound is not more than the above upper limit value, an image having good water resistance can be formed.
  • the pigment examples include the pigments exemplified above in the description of the (meth) acrylic copolymer composition.
  • the content of the pigment contained in the ink is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, based on the total mass of the ink.
  • the lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the pigment is at least the above lower limit value, the ink has excellent hiding power of the base material.
  • the content of the pigment is not more than the above upper limit value, the generation of agglomerates during printing is suppressed, and the ink has less color unevenness.
  • the ink of the present invention contains water as a solvent, but may contain a solvent other than water as an auxiliary solvent, if necessary.
  • the auxiliary solvent include the auxiliary solvent exemplified above in the description of the (meth) acrylic copolymer composition.
  • the content of the auxiliary solvent is preferably 0.1 to 30% by mass, more preferably 1 to 25% by mass, based on the total mass of the ink. The lower and upper limits of these numerical ranges can be combined arbitrarily.
  • the content of the auxiliary solvent is at least the above lower limit value, the leveling property in the water-based ink can be further improved.
  • the content of the auxiliary solvent is not more than the above upper limit value, the amount of the volatile organic compound (VOC) contained in the ink can be reduced.
  • the ink of the present invention may contain a binder for the purpose of supplementing the substrate adhesion of the ink.
  • a binder for the purpose of supplementing the substrate adhesion of the ink.
  • the binder include urethane dispersion (PUD), urethane-acrylic composite dispersion (PUA), acrylic emulsion, polyester dispersion, polyolefin dispersion, polyolefin-acrylic composite dispersion, polyolefin-polyester dispersion and the like. These may be used alone or in combination of two or more.
  • auxiliaries examples include defoaming agents, leveling agents, pigment dispersants, film-forming auxiliaries, and adhesion-imparting agents. These may be used alone or in combination of two or more.
  • the ink is obtained, for example, by adding a pigment and, if necessary, one or more of an auxiliary solvent, a binder and other auxiliary agents to a (meth) acrylic copolymer composition and mixing them. At that time, if necessary, a pigment dispersion treatment may be performed. Further, it may be further diluted with water if necessary.
  • a method for the pigment dispersion treatment an arbitrary dispersion treatment method using a commercially available rocking shaker, a planetary bead mill, a batch type stirring type bead mill, a continuous stirring type bead mill, or the like can be adopted.
  • the ink of the present invention described above is excellent in coatability, storage stability and concealment in film printing, and thus is less likely to cause bumps or uneven printing during printing.
  • the temperature (° C) corresponding to the intersection of the tangent line drawn for the point on the low temperature side and the tangent line of the point (conversion point) where the rate of change in the slope of the graph is maximum is set.
  • the next glass transition temperature (Tg) was used.
  • the water content of the (meth) acrylic copolymer is 0% when the (meth) acrylic copolymer is dried at 105 ° C. for 2 hours, and before and after drying when the (meth) acrylic copolymer is dried at 105 ° C. for 2 hours. It was calculated from the dry weight loss of the (meth) acrylic copolymer.
  • A After stirring for the first 3 hours, no precipitate was visually confirmed and the solubility was excellent.
  • methyl methacrylate was continuously added dropwise at a rate of 0.24 g / min for 75 minutes using a dropping pump, maintained at a polymerization temperature of 60 ° C. for 6 hours, and then cooled to room temperature.
  • the dispersant (1) was obtained.
  • the solid content of the obtained dispersant (1) was 7.5%.
  • Example 1 In a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer, 40 parts of methyl methacrylate, 40 parts of n-butyl methacrylate, 5 parts of n-butyl acrylate, 15 parts of methacrylic acid, and trimethylolpropane trimethacrylate 1.2. A monomer mixture in which parts are uniformly dissolved, 0.4 parts of 2,2'-azobis (2-methylbutyronitrile), 2 parts of 2-ethylhexyl 3-mercaptopropionic acid, and trimethyl propanthris (3-parts).
  • the inside of the kettle was cooled to room temperature, and the generated slurry was dehydrated by a centrifugal dehydrator (first dehydration step).
  • the obtained (meth) acrylic copolymer and pure water as a cleaning liquid are put into a cleaning tank so that the mass ratio ((meth) acrylic copolymer: cleaning liquid) is 1: 2, and the mixture is stirred for 20 minutes.
  • dehydration was performed with a centrifugal dehydrator (second dehydration step).
  • the dehydrated (meth) acrylic copolymer is put into a flow tank type dryer whose internal temperature is set to 40 ° C., and the water content of the (meth) acrylic copolymer particles becomes 10% or less. Dry (drying process).
  • Tg secondary glass transition temperature
  • Mw weight average molecular weight
  • Mn number average molecular weight
  • Solubility in was evaluated.
  • water-based ink was prepared by the above-mentioned method, and the storage stability of the ink and the hiding property of the printed matter were evaluated. The results are shown in Table 1.
  • Examples 2, 3, 5, 6, Comparative Examples 1 to 7 Particle-like solid (meth) acrylic copolymer particles were produced in the same manner as in Example 1 except for the compounding compositions shown in Tables 1 and 2, and various measurements and evaluations were performed. The results are shown in Table 1.
  • Example 4 In a glass cell equipped with a thermometer, 70 parts of methyl methacrylate, 5 parts of n-butyl acrylate, 12 parts of 2-ethylhexyl acrylate, 13 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, and tert-butyl. Uniform mixture of 0.4 part of peroxy-2-ethylhexanoate (manufactured by Nichiyu Co., Ltd., "Perbutyl O”), 4 parts of 2-ethylhexyl 3-mercaptopropionate, and 2 parts of pentaerythritol tetrakis (thioglycolate).
  • the temperature inside the glass cell was controlled to 83 ° C. in a water tank to start bulk polymerization, and after detecting the peak of polymerization heat generation, the bulk polymerization was treated at 90 ° C. for 30 minutes.
  • a (meth) acrylic copolymer was obtained (bulk polymerization step).
  • the inside of the glass cell was cooled to room temperature.
  • the lumpy solid (meth) acrylic copolymer is removed from the cell, crushed with a sanitary crusher SC-01 (manufactured by Misho Industry Co., Ltd.), and then shaken on a mesh with an opening of 2 mm to pass the passage.
  • Example 5 The particulate solid (meth) acrylic copolymer obtained in Example 4 was shaken on a mesh having an opening of 1 mm for 5 minutes, and the passage was collected to collect the particulate solid (meth) acrylic. A system copolymer was obtained.
  • Example 6 The particulate (meth) acrylic copolymer obtained in Example 4 was shaken on a mesh having an opening of 750 ⁇ m for 5 minutes, and the passage was collected to collect the particulate (meth) acrylic copolymer. A polymer was obtained.
  • -MMA Methyl methacrylate.
  • -N-BMA n-butyl methacrylate.
  • -N-BA n-butyl acrylate.
  • 2-EHA 2-ethylhexyl acrylate.
  • IBXMA Isobornyl methacrylate.
  • -MAA Methacrylic acid.
  • -TMPTMA Trimethylolpropane Trimethacrylate.
  • HDDA 1,6-hexanediol diacrylate.
  • -TMPTA Trimethylolpropane triacrylate.
  • EHMP 2-ethylhexyl 3-mercaptopropionate.
  • -EGMP Ethylene glycol bis (3-mercaptopropionate).
  • TMPMP Trimethylolpropanetris (3-mercaptopropionate).
  • -PEMP Pentaerythritol tetrakis (3-mercaptopropionate).
  • -PETG Pentaerythritol tetrakis (thioglycolate).
  • -AMBN 2,2'-azobis (2-methylbutyronitrile).
  • -Perbutyl O tert-butylperoxy-2-ethylhexanoate.
  • IBXMA is a substitute for the monomer (a) (monomer (a')).
  • the (meth) acrylic copolymer obtained in each example had good solubility in alkaline water.
  • the ink containing these (meth) acrylic copolymers has good storage stability and excellent concealment of printed matter in film printing.
  • the (meth) acrylic copolymer of Comparative Example 3 having a constituent unit of origin had poor solubility in alkaline water. Further, in the case of Comparative Example 3, although the (meth) acrylic copolymer composition was obtained, the viscosity was very high and the pigment could not be dispersed, so that the ink storage stability and the concealment of the printed matter were concealed. The sex could not be evaluated. It does not have a chemical structure derived from a trifunctional or higher functional mercaptan, but instead has a chemical structure derived from a monofunctional mercaptan or a chemical structure derived from a bifunctional mercaptan, but the ratio thereof is higher than that in Comparative Examples 1 and 2.
  • the few (meth) acrylic copolymers of Comparative Examples 4 and 5 did not dissolve in the eluent, and GPC measurement could not be performed. Moreover, the solubility in alkaline water was poor. Further, in the cases of Comparative Examples 4 and 5, although the (meth) acrylic copolymer composition was obtained, the viscosity was very high and the pigment could not be dispersed, so that the ink storage stability and the printed matter were printed. could not evaluate the concealment of.
  • the (meth) acrylic copolymers of Comparative Examples 6 and 7 having no structural unit derived from the monomer (a) or the structural unit derived from the monomer (b) had poor solubility in alkaline water. ..
  • the (meth) acrylic copolymer and the (meth) acrylic copolymer having good solubility in alkaline water and good storage stability of ink and good concealment in film printing can be obtained. It is possible to provide an ink containing the (meth) acrylic copolymer composition containing the (meth) acrylic copolymer composition and the (meth) acrylic copolymer composition. Therefore, the (meth) acrylic copolymer of the present invention can be suitably used in the field of resin compositions that can be developed with an alkaline aqueous solution, and is extremely important in industry.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

The present invention relates to: a (meth)acrylic copolymer having good solubility in alkaline water, good storage stability of ink and good hiding property in film printing; a (meth)acrylic copolymer composition containing the (meth)acrylic copolymer; and an ink containing the (meth)acrylic copolymer composition.　A (meth)acrylic copolymer according to the present invention has: a constituent unit derived from a (meth)acrylic acid alkyl ester in which an alkyl group has 1-8 carbon atoms; a constituent unit derived from an acid group-containing vinyl compound; and a chemical structure derived from a mercaptan having three or more functional groups. A (meth)acrylic copolymer composition according to the present invention contains said (meth)acrylic copolymer, water, and a basic compound. An ink according to the present invention contains said (meth)acrylic copolymer composition.

Description

（メタ）アクリル系共重合体、（メタ）アクリル系共重合体組成物およびインク(Meta) Acrylic Copolymer, (Meta) Acrylic Copolymer Composition and Ink
　本発明は、（メタ）アクリル系共重合体、（メタ）アクリル系共重合体組成物およびインクに関する。
　本願は、２０２０年１１月１８日に日本国特許庁に出願された特願２０２０－１９２００３号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to (meth) acrylic copolymers, (meth) acrylic copolymer compositions and inks.
This application claims priority based on Japanese Patent Application No. 2020-192003 filed with the Japan Patent Office on November 18, 2020, the contents of which are incorporated herein by reference.
　水系インク（水性インクともいう。）は溶剤系インクと異なり、揮発性有機化合物（ＶＯＣ）の量を低減でき、火災の危険性や変異原性などの毒性を低減できる。そのため水系インクは、グラビア印刷などの用途で広く用いられている。中でも、（メタ）アクリル酸アルキルエステル由来の構成単位、（メタ）アクリル酸由来の構成単位を含む（メタ）アクリル系重合体や（メタ）アクリル系共重合体は、透明性が高いこと、顔料の発色性が良いことから、水系インク用途で広く用いられている。 Unlike solvent-based inks, water-based inks (also called water-based inks) can reduce the amount of volatile organic compounds (VOCs), and can reduce the risk of fire and toxicity such as mutagenicity. Therefore, water-based inks are widely used in applications such as gravure printing. Among them, (meth) acrylic polymers and (meth) acrylic copolymers containing (meth) acrylic acid alkyl ester-derived structural units and (meth) acrylic acid-derived structural units have high transparency and pigments. Because of its good color development, it is widely used in water-based ink applications.
　水系インク用の（メタ）アクリル系重合体や（メタ）アクリル系共重合体は、アルカリ水への良好な溶解性に加えて、溶解時のＶＯＣの総量が少なく抑えられること、インクの貯蔵安定性、フィルム印刷時の良好な隠ぺい性が求められる。 The (meth) acrylic polymer and (meth) acrylic copolymer for water-based inks have good solubility in alkaline water, the total amount of VOC at the time of dissolution can be suppressed to a small level, and the storage stability of the ink is stable. Good properties and good concealment during film printing are required.
　特許文献１には、多官能メルカプタンを使用する溶液重合によって製造されたポリカルボン酸樹脂とポリオール樹脂を、重合溶剤とは異なる溶剤中で縮合させた後、さらに９５℃でアミンを用いて中和し脱イオン水で分散させることで、水で希釈可能な塗料用樹脂を作製する方法が記載されている。
　特許文献２には、溶液中で作製された多官能メルカプタンに対し、疎水性部位と親水性部位を導入することで、保存安定性の高い水性顔料分散物が得られる方法が記載されている。 In Patent Document 1, a polycarboxylic acid resin and a polyol resin produced by solution polymerization using polyfunctional mercaptan are condensed in a solvent different from the polymerization solvent, and then neutralized with an amine at 95 ° C. A method for producing a coating resin that can be diluted with water by dispersing it with deionized water is described.
Patent Document 2 describes a method for obtaining an aqueous pigment dispersion having high storage stability by introducing a hydrophobic moiety and a hydrophilic moiety into a polyfunctional mercaptan prepared in a solution.
特開平０４－３０４２７７号公報Japanese Unexamined Patent Publication No. 04-304277 国際公開第２０１９／０６５６０４号International Publication No. 2019/065604
　しかしながら、特許文献１に記載の方法では、溶剤の脱揮工程を繰り返し行う必要がある。加えて、樹脂の縮合や９５℃程度の高温で樹脂を溶融させたうえでアミン中和を行う必要があるため、樹脂のアルカリ水への溶解性が低い。また、水分散物を得るために必要なエネルギーの総量が大きい上に、重合工程や縮合工程で使用した溶剤が最終組成物に残留してしまうという問題がある。 However, in the method described in Patent Document 1, it is necessary to repeat the solvent devolatile step. In addition, since it is necessary to condense the resin or melt the resin at a high temperature of about 95 ° C. and then neutralize the amine, the solubility of the resin in alkaline water is low. Further, there is a problem that the total amount of energy required to obtain the aqueous dispersion is large and the solvent used in the polymerization step and the condensation step remains in the final composition.
　特許文献２の方法は、多段の重合工程により疎水性部分と親水性部分をそれぞれ導入するため、全体の重合工程が長く、生産性が悪い。加えて、重合工程で得られた（メタ）アクリル系共重合体を７０℃の高温でアルカリ中和を行う必要がある。そのため、（メタ）アクリル系共重合体のアルカリ水への溶解性が低いという問題がある。 In the method of Patent Document 2, since the hydrophobic part and the hydrophilic part are introduced by the multi-step polymerization step, the whole polymerization step is long and the productivity is poor. In addition, it is necessary to perform alkali neutralization of the (meth) acrylic copolymer obtained in the polymerization step at a high temperature of 70 ° C. Therefore, there is a problem that the (meth) acrylic copolymer has low solubility in alkaline water.
　本発明は、アルカリ水への溶解性が良好であり、インクの貯蔵安定性とフィルム印刷における隠ぺい性が良好な（メタ）アクリル系共重合体；前記（メタ）アクリル系共重合体を含む（メタ）アクリル系共重合体組成物；および前記（メタ）アクリル系共重合体組成物を含むインクを提供することを目的とする。 The present invention includes a (meth) acrylic copolymer having good solubility in alkaline water, good storage stability of ink, and good concealment in film printing; the above-mentioned (meth) acrylic copolymer ( It is an object of the present invention to provide an ink containing a (meth) acrylic copolymer composition; and the (meth) acrylic copolymer composition.
　本発明は、以下の態様を有する。
［１］　アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル由来の構成単位と、酸基含有ビニル化合物由来の構成単位と、３官能以上のメルカプタン由来の化学構造とを有し、粒子状の固体である、（メタ）アクリル系共重合体。
［２］　アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル由来の構成単位と、酸基含有ビニル化合物由来の構成単位と、３官能以上のメルカプタン由来の化学構造とを有し、単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する、（メタ）アクリル系共重合体。
［３］　前記（メタ）アクリル系共重合体の二次ガラス転移温度が、３５℃以上である、［１］または［２］の（メタ）アクリル系共重合体。
［４］　重合性二重結合を２つ以上有する化合物由来の構成単位をさらに含む、［１］～［３］のいずれかの（メタ）アクリル系共重合体。
［５］　単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する、［１］、［３］、［４］のいずれかの（メタ）アクリル系共重合体。
［６］　前記（メタ）アクリル系共重合体の質量平均粒子径が、２０～２０００μｍである、［１］～［５］のいずれかの（メタ）アクリル系共重合体。
［７］　前記（メタ）アクリル系共重合体の含水率が、０．０１～１０質量％である、［１］～［６］のいずれかの（メタ）アクリル系共重合体。
［８］　前記（メタ）アクリル系共重合体の酸価が、２０～１４０ｍｇＫＯＨ／ｇである、［１］～［７］のいずれかの（メタ）アクリル系共重合体。
［９］　前記（メタ）アクリル系共重合体の重量平均分子量が、１５０００～８００００である、［１］～［８］のいずれかの（メタ）アクリル系共重合体。
［１０］　［１］～［９］のいずれかの（メタ）アクリル系共重合体と、水と、塩基性化合物とを含む、（メタ）アクリル系共重合体組成物。
［１１］　顔料をさらに含む、［１０］の（メタ）アクリル系共重合体組成物。
［１２］　［１０］または［１１］の（メタ）アクリル系共重合体組成物を含む、インク。 The present invention has the following aspects.
[1] It has a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, a structural unit derived from an acid group-containing vinyl compound, and a chemical structure derived from a trifunctional or higher functional mercaptan. However, it is a (meth) acrylic copolymer that is a solid in the form of particles.
[2] It has a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, a structural unit derived from an acid group-containing vinyl compound, and a chemical structure derived from trifunctional or higher mercaptan. A (meth) acrylic copolymer further comprising one or more chemical structures selected from the group consisting of monofunctional mercaptan-derived chemical structures and bifunctional mercaptan-derived chemical structures.
[3] The (meth) acrylic copolymer of [1] or [2], wherein the secondary glass transition temperature of the (meth) acrylic copolymer is 35 ° C. or higher.
[4] The (meth) acrylic copolymer according to any one of [1] to [3], further comprising a structural unit derived from a compound having two or more polymerizable double bonds.
[5] Any of [1], [3], and [4], which further has one or more chemical structures selected from the group consisting of a monofunctional mercaptan-derived chemical structure and a bifunctional mercaptan-derived chemical structure. (Meta) acrylic copolymer.
[6] The (meth) acrylic copolymer according to any one of [1] to [5], wherein the (meth) acrylic copolymer has a mass average particle size of 20 to 2000 μm.
[7] The (meth) acrylic copolymer according to any one of [1] to [6], wherein the (meth) acrylic copolymer has a water content of 0.01 to 10% by mass.
[8] The (meth) acrylic copolymer according to any one of [1] to [7], wherein the acid value of the (meth) acrylic copolymer is 20 to 140 mgKOH / g.
[9] The (meth) acrylic copolymer according to any one of [1] to [8], wherein the (meth) acrylic copolymer has a weight average molecular weight of 15,000 to 80,000.
[10] A (meth) acrylic copolymer composition containing the (meth) acrylic copolymer according to any one of [1] to [9], water, and a basic compound.
[11] The (meth) acrylic copolymer composition of [10] further comprising a pigment.
[12] An ink containing the (meth) acrylic copolymer composition of [10] or [11].
　本発明によれば、アルカリ水への溶解性が良好であり、インクの貯蔵安定性とフィルム印刷における隠ぺい性が良好な（メタ）アクリル系共重合体、前記（メタ）アクリル系共重合体を含む（メタ）アクリル系共重合体組成物および前記（メタ）アクリル系共重合体組成物を含むインクを提供できる。 According to the present invention, the (meth) acrylic copolymer and the (meth) acrylic copolymer having good solubility in alkaline water and good storage stability of ink and good concealment in film printing can be obtained. It is possible to provide an ink containing the (meth) acrylic copolymer composition containing the (meth) acrylic copolymer composition and the (meth) acrylic copolymer composition.
　以下、本発明を詳細に説明する。以下の実施の形態は、本発明を説明するための単なる例示であって、本発明をこの実施の形態にのみ限定することは意図されない。本発明は、その趣旨を逸脱しない限り、様々な態様で実施することが可能である。 Hereinafter, the present invention will be described in detail. The following embodiments are merely exemplary to illustrate the invention and are not intended to limit the invention to this embodiment alone. The present invention can be carried out in various embodiments as long as it does not deviate from the gist thereof.
　本明細書において、「（メタ）アクリル酸」とは、アクリル酸とメタクリル酸の総称である。「（メタ）アクリル系」とは、アクリル系とメタクリル系の総称である。「（メタ）アクリル系共重合体」とは、例えばアクリロイル基およびメタクリロイル基の少なくとも一方を有する共重合体である。
　本明細書において、「（メタ）アクリレート」とは、アクリレートとメタクリレートの総称である。
　本明細書において、（メタ）アクリル系共重合体の各構成単位の割合とメルカプタン由来の化学構造の割合は、重合原料に用いた各単量体とメルカプタンの質量比から算出したものを意味する。
　本明細書において「室温」とは、特に断りの無い限り２３℃±２℃の範囲内の温度を意味する。 As used herein, "(meth) acrylic acid" is a general term for acrylic acid and methacrylic acid. "(Meta) acrylic" is a general term for acrylic and methacrylic. The "(meth) acrylic copolymer" is, for example, a copolymer having at least one of an acryloyl group and a methacryloyl group.
As used herein, "(meth) acrylate" is a general term for acrylate and methacrylate.
In the present specification, the ratio of each structural unit of the (meth) acrylic copolymer and the ratio of the chemical structure derived from mercaptan mean those calculated from the mass ratio of each monomer used as the polymerization raw material and mercaptan. ..
As used herein, the term "room temperature" means a temperature within the range of 23 ° C. ± 2 ° C. unless otherwise specified.
［（メタ）アクリル系共重合体］
　＜第一の態様の（メタ）アクリル系共重合体＞
　本発明の第一の態様の（メタ）アクリル系共重合体は、アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル（以下、「単量体（ａ）」ともいう。）由来の構成単位と、酸基含有ビニル化合物（以下、「単量体（ｂ）」ともいう。）由来の構成単位と、３官能以上のメルカプタン由来の化学構造とを有する。
　第一の態様の（メタ）アクリル系共重合体は、単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有することが好ましい。また、（メタ）アクリル系共重合体は、単量体（ａ）および単量体（ｂ）以外の他の単量体（以下、「単量体（ｃ）」ともいう。）由来の構成単位をさらに有していてもよい。 [(Meta) acrylic copolymer]
<The (meth) acrylic copolymer of the first aspect>
The (meth) acrylic copolymer according to the first aspect of the present invention is also referred to as a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (hereinafter, also referred to as “monomer (a)”. ), A structural unit derived from an acid group-containing vinyl compound (hereinafter, also referred to as “monomer (b)”), and a chemical structure derived from a trifunctional or higher functional mercaptan.
The (meth) acrylic copolymer of the first aspect further preferably has one or more chemical structures selected from the group consisting of a monofunctional mercaptan-derived chemical structure and a bifunctional mercaptan-derived chemical structure. .. Further, the (meth) acrylic copolymer has a structure derived from a monomer other than the monomer (a) and the monomer (b) (hereinafter, also referred to as “monomer (c)”). It may have more units.
　＜第二の態様の（メタ）アクリル系共重合体＞
　本発明の第二の態様の（メタ）アクリル系共重合体は、単量体（ａ）由来の構成単位と、単量体（ｂ）由来の構成単位と、３官能以上のメルカプタン由来の化学構造とを有し、単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する。また、第二の態様の（メタ）アクリル系共重合体は、単量体（ｃ）由来の構成単位をさらに有していてもよい。 <The (meth) acrylic copolymer of the second aspect>
The (meth) acrylic copolymer of the second aspect of the present invention has a structural unit derived from the monomer (a), a structural unit derived from the monomer (b), and a chemistry derived from trifunctional or higher functional mercaptan. It has a structure and further has one or more chemical structures selected from the group consisting of a monofunctional mercaptan-derived chemical structure and a bifunctional mercaptan-derived chemical structure. Further, the (meth) acrylic copolymer of the second aspect may further have a structural unit derived from the monomer (c).
＜アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル＞
　本発明の第一の態様および第二の態様の（メタ）アクリル系共重合体は、アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル由来の構成単位、すなわち、単量体（ａ）由来の構成単位を有する。
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ａ）としては、例えば（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ｎ－プロピル、（メタ）アクリル酸イソプロピル、（メタ）アクリル酸ｎ－ブチル、（メタ）アクリル酸ｓｅｃ－ブチル、（メタ）アクリル酸ｔｅｒｔ－ブチル、（メタ）アクリル酸イソブチル、（メタ）アクリル酸ｎ－ヘキシル、（メタ）アクリル酸ｎ－オクチル、（メタ）アクリル酸２－エチルヘキシル、（メタ）アクリル酸イソオクチルが挙げられる。
　これらの中でも、（メタ）アクリル系共重合体のアルカリ水への溶解性がより良好となり、入手も容易である点から、（メタ）アクリル酸メチル、（メタ）アクリル酸ｎ－ブチル、アクリル酸２－エチルヘキシルが好ましい。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 <(Meta) acrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group>
The (meth) acrylic copolymer of the first aspect and the second aspect of the present invention is a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, that is, a single amount. It has a structural unit derived from the body (a).
Examples of the monomer (a) in the (meth) acrylic copolymer of the first aspect and the second aspect include methyl (meth) acrylate, ethyl (meth) acrylate, and n- (meth) acrylate. Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n- (meth) acrylate. Examples thereof include hexyl, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate.
Among these, methyl (meth) acrylate, n-butyl (meth) acrylate, and acrylic acid are available because the (meth) acrylic copolymer has better solubility in alkaline water and is easily available. 2-Ethylhexyl is preferred.
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ａ）由来の構成単位の割合は、単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位の合計１００質量％中、６０～９７質量％が好ましく、８０～９５質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　単量体（ａ）由来の構成単位の割合が上記範囲内であれば、インクの製膜性および耐水性が良好となる。 The proportion of the structural unit derived from the monomer (a) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b). Of the total 100% by mass of the derived constituent units, 60 to 97% by mass is preferable, and 80 to 95% by mass is more preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the ratio of the structural unit derived from the monomer (a) is within the above range, the film forming property and the water resistance of the ink are good.
＜酸基含有ビニル化合物＞
　本発明の第一の態様および第二の態様の（メタ）アクリル系共重合体は、酸基含有ビニル化合物由来の構成単位、すなわち単量体（ｂ）由来の構成単位を有する。
　単量体（ｂ）としては、例えばカルボン酸またはスルホン酸などの酸基を有するビニル化合物などが挙げられる。
　第一の態様および第二の態様の（メタ）アクリル系共重合体におけるカルボン酸基を有するビニル化合物の具体例としては、（メタ）アクリル酸、クロトン酸などの一塩基酸；フマール酸、マレイン酸、イタコン酸などの二塩基酸；これら二塩基酸の部分エステルなどが挙げられる。
　スルホン酸基を有するビニル化合物の具体例としては、ビニルスルホン酸、２－アクリルアミド－２－メチルプロパンスルホン酸などが挙げられる。
　これらの中でも、（メタ）アクリル系共重合体の水溶性が良好となる点から、カルボン酸基を有するビニル化合物が好ましく、（メタ）アクリル酸がより好ましい。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 <Acid group-containing vinyl compound>
The (meth) acrylic copolymer of the first aspect and the second aspect of the present invention has a structural unit derived from an acid group-containing vinyl compound, that is, a structural unit derived from the monomer (b).
Examples of the monomer (b) include vinyl compounds having an acid group such as carboxylic acid or sulfonic acid.
Specific examples of the vinyl compound having a carboxylic acid group in the (meth) acrylic copolymer of the first aspect and the second aspect include monobasic acids such as (meth) acrylic acid and crotonic acid; fumaric acid and malein. Bibasic acids such as acids and itaconic acids; partial esters of these dibasic acids and the like can be mentioned.
Specific examples of the vinyl compound having a sulfonic acid group include vinyl sulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and the like.
Among these, a vinyl compound having a carboxylic acid group is preferable, and (meth) acrylic acid is more preferable, from the viewpoint of improving the water solubility of the (meth) acrylic copolymer.
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ｂ）由来の構成単位の割合は、単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位の合計１００質量％中、３～４０質量％が好ましく、５～２０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　単量体（ｂ）由来の構成単位の割合が上記範囲内であれば、（メタ）アクリル系共重合体のアルカリ水への溶解性、その他溶剤に対する溶解性がより良好となる。 The proportion of the structural unit derived from the monomer (b) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b). Of the total 100% by mass of the derived constituent units, 3 to 40% by mass is preferable, and 5 to 20% by mass is more preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the ratio of the structural unit derived from the monomer (b) is within the above range, the solubility of the (meth) acrylic copolymer in alkaline water and the solubility in other solvents are better.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位の合計割合は、（メタ）アクリル系共重合体を構成する全ての構成単位の総質量に対して、７０～９９．９質量％が好ましく、８０～９９質量％がより好ましく、８５～９５質量％がさらに好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位の合計割合が上記範囲内であれば、アルカリ水への溶解性が極めて良好となる。
　本明細書において、第一の態様および第二の態様の（メタ）アクリル系共重合体を構成する全ての構成単位の総質量には、後述するメタカプタン由来の化学構造の割合も含まれる。 The total ratio of the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b) in the (meth) acrylic copolymer of the first aspect and the second aspect is the (meth) acrylic system. 70 to 99.9% by mass is preferable, 80 to 99% by mass is more preferable, and 85 to 95% by mass is further preferable with respect to the total mass of all the constituent units constituting the copolymer. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the total ratio of the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b) is within the above range, the solubility in alkaline water is extremely good.
In the present specification, the total mass of all the structural units constituting the (meth) acrylic copolymer of the first aspect and the second aspect also includes the ratio of the chemical structure derived from metacaptan, which will be described later.
＜メルカプタン＞
　第一の態様および第二の態様の（メタ）アクリル系共重合体は、３官能以上のメルカプタン由来の化学構造を有する。
　詳しくは後述するが、第一の態様および第二の態様の（メタ）アクリル系共重合体を製造する際に重合反応における連鎖移動剤として３官能以上のメルカプタンを使用することで、３官能以上のメルカプタンが重合の開始点となり、３官能以上のメルカプタン由来の化学構造が（メタ）アクリル系共重合体に導入される。 <Mercaptan>
The (meth) acrylic copolymer of the first aspect and the second aspect has a chemical structure derived from a trifunctional or higher functional mercaptan.
As will be described in detail later, by using a trifunctional or higher functional mercaptan as a chain transfer agent in the polymerization reaction when producing the (meth) acrylic copolymer of the first aspect and the second aspect, the trifunctional or higher functionality is used. The mercaptan of the above becomes the starting point of the polymerization, and the chemical structure derived from the trifunctional or higher mercaptan is introduced into the (meth) acrylic copolymer.
　３官能以上のメルカプタンは、単一分子内に３つ以上のメルカプト基を持つ化合物である。
　第一の態様および第二の態様の（メタ）アクリル系共重合体における３官能以上のメルカプタンとしては、例えば１，２，３－トリメルカプトプロパン、２，２－ビス（メルカプトメチル）－１－メルカプトブタン、１，２，３，４－テトラメルカプトブタン、２，２－ビス（メルカプトメチル）－１，３－ジメルカプトプロパン、グリセリントリス（３－メルカプトプロピオネート）、トリメチロールプロパントリス（３－メルカプトプロピオネート）、ペンタエリトリトールテトラキス（３－メルカプトプロピオネート）、ジペンタエリスリトールヘキサキス（３－メルカプトプロピオネート）、グリセリントリス（チオグリコレート）、トリメチロールプロパントリス（チオグリコレート）、ペンタエリトリトールテトラキス（チオグリコレート）、ジペンタエリスリトールヘキサキス（チオグリコレート）、トリメチロールプロパントリス（２－メルカプトブチレート）、ペンタエリトリトールテトラキス（２－メルカプトブチレート）、ジペンタエリスリトールヘキサキス（２－メルカプトブチレート）などが挙げられる。
　これらの中でも、（メタ）アクリル系共重合体のアルカリ水への溶解性がより良好となり、入手も容易である点から、トリメチロールプロパントリス（３－メルカプトプロピオネート）、ペンタエリトリトールテトラキス（３－メルカプトプロピオネート）、ペンタエリトリトールテトラキス（チオグリコレート）が好ましい。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 A trifunctional or higher functional mercaptan is a compound having three or more mercapto groups in a single molecule.
Examples of the trifunctional or higher functional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect include 1,2,3-trimercaptopropane and 2,2-bis (mercaptomethyl) -1-. Mercaptobutane, 1,2,3,4-tetramercaptobutane, 2,2-bis (mercaptomethyl) -1,3-dimercaptopropane, glycerintris (3-mercaptopropionate), trimethylpropanthris (3) -Mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), glycerintris (thioglycolate), trimetylolpropanthris (thioglycolate) , Pentaerythritol tetrakis (thioglycolate), dipentaerythritol hexakiss (thioglycolate), trimethylolpropanthris (2-mercaptobutyrate), pentaerythritol tetrakis (2-mercaptobutyrate), dipentaerythritol hexakis (2-mercaptobutyrate) 2-Mercaptobutyrate) and the like.
Among these, trimethylol propanthris (3-mercaptopropionate) and pentaerythritol tetrakis (3) are available because the (meth) acrylic copolymer has better solubility in alkaline water and is easily available. -Mercaptopropionate), pentaerythritol tetrakis (thioglycolate) are preferred.
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における３官能以上のメルカプタン由来の化学構造の割合は、（メタ）アクリル系共重合体を構成する全ての単量体由来の構成単位の合計１００質量部に対して、０．１～２０質量部が好ましく、１～６質量部がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　３官能以上のメルカプタン由来の化学構造の割合が上記下限値以上であれば、（メタ）アクリル系共重合体のアルカリ水への溶解性がより良好となる傾向にある。３官能以上のメルカプタン由来の化学構造の割合が上記上限値以下であれば、（メタ）アクリル系共重合体の臭気が抑制される。 The proportion of the chemical structure derived from the trifunctional or higher mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect is derived from all the monomers constituting the (meth) acrylic copolymer. 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the constituent units. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the proportion of the chemical structure derived from the trifunctional or higher mercaptan is at least the above lower limit, the solubility of the (meth) acrylic copolymer in alkaline water tends to be better. When the ratio of the chemical structure derived from the trifunctional or higher mercaptan is not more than the above upper limit value, the odor of the (meth) acrylic copolymer is suppressed.
　第一の態様の（メタ）アクリル系共重合体は、３官能以上のメルカプタン由来の化学構造に加えて、単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有することが好ましい。第一の態様の（メタ）アクリル系共重合体が単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する場合、アルカリ水への溶解時の粘度が低くなり、顔料などの配合が容易になる。 The (meth) acrylic copolymer of the first aspect is selected from the group consisting of a chemical structure derived from a trifunctional or higher functional mercaptan, a chemical structure derived from a monofunctional mercaptan, and a chemical structure derived from a bifunctional mercaptan. It is preferable to further have one or more chemical structures. If the (meth) acrylic copolymer of the first aspect further has one or more chemical structures selected from the group consisting of monofunctional mercaptan-derived chemical structures and bifunctional mercaptan-derived chemical structures, alkaline water. The viscosity at the time of dissolution in is lowered, and it becomes easy to mix pigments and the like.
　第二の態様の（メタ）アクリル系共重合体は、３官能以上のメルカプタン由来の化学構造に加えて、３官能以上のメルカプタン由来の化学構造に加えて、単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する。そのため、第二の態様の（メタ）アクリル系共重合体によれば、アルカリ水への溶解時の粘度が低くなり、顔料などの配合が容易になる。 The (meth) acrylic copolymer of the second aspect has a chemical structure derived from a trifunctional or higher mercaptan, a chemical structure derived from a trifunctional or higher mercaptan, and a chemical structure derived from a monofunctional mercaptan. It further has one or more chemical structures selected from the group consisting of bifunctional mercaptan-derived chemical structures. Therefore, according to the (meth) acrylic copolymer of the second aspect, the viscosity at the time of dissolution in alkaline water becomes low, and the compounding of a pigment or the like becomes easy.
　単官能のメルカプタンは、単一分子内に１つのメルカプト基を持つ化合物である。
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単官能のメルカプタンとしては、例えばｎ－オクチルメルカプタン、ｎ－ドデシルメルカプタン、ｔｅｒｔ－ドデシルメルカプタン、ｎ－ブチルメルカプタン、チオグリコール酸、３－メルカプトプロピオン酸、２－メルカプトエタノール、３－メルカプトプロピオン酸２－エチルヘキシル、チオグリコール酸２－エチルヘキシル、３－メルカプトプロピオン酸イソオクチル、チオグリコール酸イソオクチル、３－メルカプトプロピオン酸２－メトキシブチルなどが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 A monofunctional mercaptan is a compound having one mercapto group in a single molecule.
Examples of the monofunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, and thioglycolic acid. , 3-Mercaptopropionic acid, 2-mercaptoethanol, 3-mercaptopropionic acid 2-ethylhexyl, 2-ethylhexyl thioglycolate, 3-mercaptopropionic acid isooctyl, thioglycolate isooctyl, 3-mercaptopropionic acid 2-methoxybutyl, etc. Can be mentioned.
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単官能のメルカプタン由来の化学構造の割合は、（メタ）アクリル系共重合体を構成する全ての単量体由来の構成単位の合計１００質量部に対して、０．１～２０質量部が好ましく、１～６質量部がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　単官能のメルカプタン由来の化学構造の割合が上記下限値以上であれば、（メタ）アクリル系共重合体のアルカリ水への溶解性がより良好となる傾向にある。単官能のメルカプタン由来の化学構造の割合が上記上限値以下であれば、（メタ）アクリル系共重合体の臭気が抑制される。 The proportion of the chemical structure derived from the monofunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect is the composition derived from all the monomers constituting the (meth) acrylic copolymer. 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the unit. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the ratio of the chemical structure derived from the monofunctional mercaptan is at least the above lower limit, the solubility of the (meth) acrylic copolymer in alkaline water tends to be better. When the ratio of the chemical structure derived from the monofunctional mercaptan is not more than the above upper limit value, the odor of the (meth) acrylic copolymer is suppressed.
　２官能のメルカプタンは、単一分子内に２つのメルカプト基を持つ化合物である。
　第一の態様および第二の態様の（メタ）アクリル系共重合体における２官能のメルカプタンとしては、例えば１，４－ジメルカプトブタン、３－オキソ－１，５－ペンタンジチオール、３－チア－１，５－ペンタンジチオール、エチレングリコールビス（３－メルカプトプロピオネート）、１，４－ブタンジオールビス（チオグリコ―レート）などが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 A bifunctional mercaptan is a compound having two mercapto groups in a single molecule.
Examples of the bifunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect include 1,4-dimercaptobutane, 3-oxo-1,5-pentanedithiol, and 3-thia-. Examples thereof include 1,5-pentanedithiol, ethylene glycol bis (3-mercaptopropionate), and 1,4-butanediol bis (thioglycolate).
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における２官能のメルカプタン由来の化学構造の割合は、（メタ）アクリル系共重合体を構成する全ての単量体由来の構成単位の合計１００質量部に対して、０．１～２０質量部が好ましく、１～６質量部がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　２官能のメルカプタン由来の化学構造の割合が上記下限値以上であれば、（メタ）アクリル系共重合体のアルカリ水への溶解性がより良好となる傾向にある。２官能のメルカプタン由来の化学構造の割合が上記上限値以下であれば、（メタ）アクリル系共重合体の臭気が抑制される。 The proportion of the chemical structure derived from the bifunctional mercaptan in the (meth) acrylic copolymer of the first aspect and the second aspect is the composition derived from all the monomers constituting the (meth) acrylic copolymer. 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the unit. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the ratio of the chemical structure derived from the bifunctional mercaptan is at least the above lower limit, the solubility of the (meth) acrylic copolymer in alkaline water tends to be better. When the ratio of the chemical structure derived from the bifunctional mercaptan is not more than the above upper limit value, the odor of the (meth) acrylic copolymer is suppressed.
＜他の単量体＞
　第一の態様および第二の態様の（メタ）アクリル系共重合体は、単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位に加えて、他の単量体（単量体（ｃ））由来の構成単位をさらに有していてもよい。
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ｃ）としては、重合性二重結合を１つ有する化合物（以下、「単量体（ｃ１）」ともいう。）、重合性二重結合を２つ以上有する化合物（以下、「単量体（ｃ２）」ともいう。）などが挙げられる。これらの中でも、単量体（ｃ）としては単量体（ｃ２）が好ましい。すなわち、（メタ）アクリル系共重合体は、単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位に加えて、単量体（ｃ２）由来の構成単位をさらに有することが好ましい。 <Other monomers>
The (meth) acrylic copolymer of the first aspect and the second aspect is a structural unit derived from the monomer (a) and a structural unit derived from the monomer (b), as well as other monomers. It may further have a structural unit derived from (monomer (c)).
The monomer (c) in the (meth) acrylic copolymer of the first aspect and the second aspect is also referred to as a compound having one polymerizable double bond (hereinafter, “monomer (c1)”). ), Compounds having two or more polymerizable double bonds (hereinafter, also referred to as “monomer (c2)”) and the like can be mentioned. Among these, the monomer (c2) is preferable as the monomer (c). That is, the (meth) acrylic copolymer further has a structural unit derived from the monomer (c2) in addition to the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b). Is preferable.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ｃ１）としては、例えばスチレン、ｏ－メチルスチレン、ｍ－メチルスチレン、ｐ－メチルスチレン、α－メチルスチレン、ｏ－メトキシスチレン、ｍ－メトキシチレン、ｐ－メトキシスチレン、４－（ｔｅｒｔ－ブチル）スチレン、ｐ－（ｔｅｒｔ－ブトキシ）スチレン、１－ビニルナフタレン、２－ビニルナフタレン、フェニル（メタ）アクリレート、ベンジル（メタ）アクリレート、２－フェノキシエチル（メタ）アクリレート、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート、ステアリル（メタ）アクリレート、ラウリル（メタ）アクリレートなどが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Examples of the monomer (c1) in the (meth) acrylic copolymer of the first aspect and the second aspect include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and α-methylstyrene. , O-methoxystyrene, m-methoxytyrene, p-methoxystyrene, 4- (tert-butyl) styrene, p- (tert-butoxy) styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, phenyl (meth) acrylate, Benzyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, stearyl (meth) acrylate, lauryl ( Meta) acrylate and the like can be mentioned.
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ｃ１）由来の構成単位の割合は、単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位の合計１００質量部に対して、０．１～２０質量部が好ましく、１～６質量部がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　単量体（ｃ１）由来の構成単位の割合が上記下限値以上であれば、インクの貯蔵安定性がより良好となる傾向にある。単量体（ｃ１）由来の構成単位の割合が上記上限値以下であれば、インクの粘度を下げることができ、印刷時の取扱いが良好となる。 The proportion of the structural unit derived from the monomer (c1) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b). 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the derived constituent units. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the ratio of the structural unit derived from the monomer (c1) is at least the above lower limit value, the storage stability of the ink tends to be better. When the ratio of the structural unit derived from the monomer (c1) is not more than the above upper limit value, the viscosity of the ink can be lowered and the handling at the time of printing becomes good.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ｃ２）としては、例えばエチレングリコールジ（メタ）アクリレート、１，２－プロピレングリコールジ（メタ）アクリレート、１，４－ブタンジオールジ（メタ）アクリレート、１，６－ヘキサンジオールジ（メタ）アクリレート、１，４－シクロヘキサンジメタノールジ（メタ）アクリレート、ネオペンチルグリコールジ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、１，３－プロピレングリコールジ（メタ）アクリレート、トリメチロールプロパンジ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、ペンタエリトリトールトリ（メタ）アクリレート、ペンタエリトリトールテトラ（メタ）アクリレート、ビスフェノールＡジ（メタ）アクリレート、２，２－ビス｛４－〔２－（アクリロイルオキシ）エトキシ）〕フェニル｝プロパン、２，２－ビス｛４－〔２－（メタクリロイルオキシ）エトキシ）〕フェニル｝プロパン、トリシクロデカンジメタノールジ（メタ）アクリレート、１，１０－デカンジオールジ（メタ）アクリレート、ジプロピレングリコールジ（メタ）アクリレート、グリセリントリ（メタ）アクリレート、エトキシ変性イソシアヌル酸トリ（メタ）アクリレート、ジペンタエリトリトールヘキサ（メタ）アクリレート、１，４－ジビニルベンゼン、１，３，５－トリビニルベンゼンなどが挙げられる。
　これらの中でも、アルカリ水への溶解時の粘度が低くなり、顔料などの配合が容易になる点から、エチレングリコールジアクリレート、１，６－ヘキサンジオールジ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレートが好ましい。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Examples of the monomer (c2) in the (meth) acrylic copolymer of the first aspect and the second aspect include ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, and 1 , 4-Butandiol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanedimethanol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) ) Acrylate, 1,3-propylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, bisphenol A-di (meth) acrylate, 2,2-bis {4- [2- (acryloyloxy) ethoxy)] phenyl} propane, 2,2-bis {4- [2- (methacryloyloxy) ethoxy)] phenyl} propane , Tricyclodecanedimethanol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, ethoxy-modified isocyanuric acid tri (meth) acrylate, Examples thereof include dipentaerytritor hexa (meth) acrylate, 1,4-divinylbenzene and 1,3,5-trivinylbenzene.
Among these, ethylene glycol diacrylate, 1,6-hexanediol di (meth) acrylate, and trimethylolpropane tri (meth) are low in viscosity when dissolved in alkaline water and can be easily blended with pigments. ) Acrylate is preferred.
These may be used alone or in combination of two or more.
　第一の態様および第二の態様の（メタ）アクリル系共重合体における単量体（ｃ２）由来の構成単位の割合は、単量体（ａ）由来の構成単位および単量体（ｂ）由来の構成単位の合計１００質量部に対して、０．１～２０質量部が好ましく、１～６質量部がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　単量体（ｃ２）由来の構成単位の割合が上記下限値以上であれば、インクの貯蔵安定性がより良好となる傾向にある。単量体（ｃ２）由来の構成単位の割合が上記上限値以下であれば、インクの粘度を下げることができ、印刷時の取扱いが良好となる。 The proportion of the structural unit derived from the monomer (c2) in the (meth) acrylic copolymer of the first aspect and the second aspect is the structural unit derived from the monomer (a) and the monomer (b). 0.1 to 20 parts by mass is preferable, and 1 to 6 parts by mass is more preferable with respect to a total of 100 parts by mass of the derived constituent units. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the ratio of the structural unit derived from the monomer (c2) is at least the above lower limit value, the storage stability of the ink tends to be better. When the ratio of the structural unit derived from the monomer (c2) is not more than the above upper limit value, the viscosity of the ink can be lowered and the handling at the time of printing becomes good.
＜物性＞
　第一の態様の（メタ）アクリル系共重合体は、室温で固体である。第一の態様の（メタ）アクリル系共重合体は室温で固体であるため、アルカリ水に溶解した際のＶＯＣを低減できる。加えて、水に溶解した状態（水溶液）や水に分散した状態（分散液）に比べて嵩が増すのを抑制できるため、輸送や保管の際にも好適である。
　第二の態様の（メタ）アクリル系共重合体も室温で固体であることが好ましい。第二の態様の（メタ）アクリル系共重合体が室温で固体である場合、アルカリ水に溶解した際のＶＯＣを低減できる。加えて、水に溶解した状態（水溶液）や水に分散した状態（分散液）に比べて嵩が増すのを抑制できるため、輸送や保管の際にも好適である。
　固体の（メタ）アクリル系共重合体の具体的な形状としては、粉体状、板状、破砕片状、球状、粒子状、顆粒状、ペレット状の固体などが挙げられる。これらの中でも、溶剤やアルカリ水に溶解する際の取り扱い性が容易である点から、粉体状、破砕片状、球状、粒子状、顆粒状の固体が好ましい。
　第一の態様および第二の態様の（メタ）アクリル系共重合体は、後述する塩基性化合物で中和することにより、水、または水と後述の補助溶剤との混合溶剤に容易に溶解できる。 <Physical characteristics>
The (meth) acrylic copolymer of the first aspect is solid at room temperature. Since the (meth) acrylic copolymer of the first aspect is solid at room temperature, VOC when dissolved in alkaline water can be reduced. In addition, it is suitable for transportation and storage because it can suppress the increase in volume as compared with the state of being dissolved in water (aqueous solution) and the state of being dispersed in water (dispersion liquid).
The (meth) acrylic copolymer of the second aspect is also preferably solid at room temperature. When the (meth) acrylic copolymer of the second aspect is solid at room temperature, VOC when dissolved in alkaline water can be reduced. In addition, it is suitable for transportation and storage because it can suppress the increase in volume as compared with the state of being dissolved in water (aqueous solution) and the state of being dispersed in water (dispersion liquid).
Specific shapes of the solid (meth) acrylic copolymer include powder-like, plate-like, crushed-like, spherical, particle-like, granular, and pellet-like solids. Among these, powdery, crushed, spherical, particulate, and granular solids are preferable because they are easy to handle when dissolved in a solvent or alkaline water.
The (meth) acrylic copolymer of the first aspect and the second aspect can be easily dissolved in water or a mixed solvent of water and an auxiliary solvent described later by neutralizing with a basic compound described later. ..
　第一の態様および第二の態様の（メタ）アクリル系共重合体の二次ガラス転移温度（Ｔｇ）は、３５℃以上が好ましく、４０℃以上がより好ましく、４５℃以上がさらに好ましい。第一の態様および第二の態様の（メタ）アクリル系共重合体の二次ガラス転移温度（Ｔｇ）は、７０℃以下が好ましく、６０℃以下がより好ましく、５５℃以下がさらに好ましい。これらの下限値および上限値は任意に組み合わせることができる。
　第一の態様および第二の態様の（メタ）アクリル系共重合体の二次ガラス転移温度（Ｔｇ）が上記範囲内であれば、アルカリ水への溶解時に共重合体粒子間の凝集が抑制され、アルカリ水への溶解性がより良好となる。
　第一の態様および第二の態様の（メタ）アクリル系共重合体の二次ガラス転移温度（Ｔｇ）は、示差走査熱量計（ＤＳＣ）を用いて測定することができ、その具体的な測定方法は実施例の項に記載される通りである。 The secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 35 ° C. or higher, more preferably 40 ° C. or higher, still more preferably 45 ° C. or higher. The secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 70 ° C. or lower, more preferably 60 ° C. or lower, still more preferably 55 ° C. or lower. These lower and upper limits can be combined arbitrarily.
When the secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect is within the above range, aggregation between the copolymer particles is suppressed when dissolved in alkaline water. Therefore, the solubility in alkaline water becomes better.
The secondary glass transition temperature (Tg) of the (meth) acrylic copolymer of the first aspect and the second aspect can be measured using a differential scanning calorimeter (DSC), and the specific measurement thereof. The method is as described in the section of Examples.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の質量平均粒子径は、２０～２０００μｍが好ましく、５０～８５０μｍがより好ましく、８０～７００μｍがさらに好ましく、１５０～６００μｍが特に好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　（メタ）アクリル系共重合体の質量平均粒子径が上記下限値以上であれば、配合作業が容易になる。また、（メタ）アクリル系共重合体の質量平均粒子径が上記上限値以下であれば、アルカリ水への溶解時間が短縮される。
　（メタ）アクリル系共重合体の質量平均粒子径は、標準ふるいを使用して、粒状樹脂２０ｇを５分間振とうして分級することで算出できる。 The mass average particle size of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 20 to 2000 μm, more preferably 50 to 850 μm, further preferably 80 to 700 μm, and particularly preferably 150 to 600 μm. preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the mass average particle size of the (meth) acrylic copolymer is at least the above lower limit, the compounding work becomes easy. Further, when the mass average particle size of the (meth) acrylic copolymer is not more than the above upper limit value, the dissolution time in alkaline water is shortened.
The mass average particle size of the (meth) acrylic copolymer can be calculated by shaking 20 g of the granular resin for 5 minutes using a standard sieve to classify the (meth) acrylic copolymer.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の含水率は、アクリル系共重合体の総質量に対して０．０１～１０質量％が好ましく、０．０２～８．０質量％がより好ましく、０．１～５．０質量％がさらに好ましく、０．５～５．０質量％が特に好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　（メタ）アクリル系共重合体の含水率が上記下限値以上であれば、アルカリ水への溶解性が良好となる。また、（メタ）アクリル系共重合体の含水率が上記上限値以下であれば、印刷物の耐水性が高くなる。また、（メタ）アクリル系共重合体の含水率が上記範囲内であれば、粒子状の（メタ）アクリル系共重合体を得た際の共重合体の取り扱い性が良好となる。
　（メタ）アクリル系共重合体の含水率の具体的な測定方法は、実施例の項に記載される通りである。 The water content of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 0.01 to 10% by mass, and 0.02 to 8. 0% by mass is more preferable, 0.1 to 5.0% by mass is further preferable, and 0.5 to 5.0% by mass is particularly preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the water content of the (meth) acrylic copolymer is at least the above lower limit, the solubility in alkaline water is good. Further, when the water content of the (meth) acrylic copolymer is not more than the above upper limit value, the water resistance of the printed matter is high. Further, when the water content of the (meth) acrylic copolymer is within the above range, the handleability of the copolymer when the particulate (meth) acrylic copolymer is obtained is good.
The specific method for measuring the water content of the (meth) acrylic copolymer is as described in the section of Examples.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の酸価は、２０～１４０ｍｇＫＯＨ／ｇが好ましく、５０～１００ｍｇＫＯＨ／ｇがより好ましく、５５～９０ｍｇＫＯＨ／ｇがさらに好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　（メタ）アクリル系共重合体の酸価が上記下限値以上であれば、アルカリ水への溶解性がより良好となる。（メタ）アクリル系共重合体の酸価が上記上限値以下であれば、中和溶解に必要とする塩基性化合物の量を減らすことができ、印刷物の耐水性も良好となる。
　（メタ）アクリル系共重合体の酸価とは、（メタ）アクリル系共重合体１ｇを中和するのに必要な水酸化カリウムの質量をミリグラム数で表した値を意味する。第一の態様及び第二の態様の（メタ）アクリル系共重合体の酸価は、フェノールフタレインの変色点を基準にした、水酸化カリウム溶液による中和滴定により測定できる。具体的な測定方法は、実施例の項に記載される通りである。 The acid value of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 20 to 140 mgKOH / g, more preferably 50 to 100 mgKOH / g, still more preferably 55 to 90 mgKOH / g. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the acid value of the (meth) acrylic copolymer is at least the above lower limit, the solubility in alkaline water becomes better. When the acid value of the (meth) acrylic copolymer is not more than the above upper limit, the amount of the basic compound required for neutralization and dissolution can be reduced, and the water resistance of the printed matter is also good.
The acid value of the (meth) acrylic copolymer means a value expressed in milligrams of the mass of potassium hydroxide required to neutralize 1 g of the (meth) acrylic copolymer. The acid value of the (meth) acrylic copolymer of the first aspect and the second aspect can be measured by neutralization titration with a potassium hydroxide solution based on the discoloration point of phenolphthalein. The specific measurement method is as described in the section of Examples.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の重量平均分子量（Ｍｗ）は、１５０００～８００００が好ましく、１５０００～６００００がより好ましく、２００００～６００００がさらに好ましく、２５０００～６００００が特に好ましく、２５０００～４００００が最も好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　（メタ）アクリル系共重合体の重量平均分子量が上記下限値以上であれば、インクの貯蔵安定性がより良好となる傾向にある。（メタ）アクリル系共重合体の重量平均分子量が上記上限値以下であれば、インクの粘度が低くなり、製膜性が良好となる傾向がある。
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の重量平均分子量（Ｍｗ）は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によって測定される重量平均分子量（ポリスチレン換算）である。具体的な測定方法は実施例の項に記載される通りである。 The weight average molecular weight (Mw) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 15,000 to 80,000, more preferably 15,000 to 60,000, further preferably 20,000 to 60,000, and even more preferably 25,000 to 60,000. Is particularly preferable, and 25,000 to 40,000 is most preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the weight average molecular weight of the (meth) acrylic copolymer is at least the above lower limit, the storage stability of the ink tends to be better. When the weight average molecular weight of the (meth) acrylic copolymer is not more than the above upper limit, the viscosity of the ink tends to be low and the film forming property tends to be good.
The weight average molecular weight (Mw) of the (meth) acrylic copolymer of the first aspect and the second aspect is the weight average molecular weight (in terms of polystyrene) measured by gel permeation chromatography (GPC). The specific measurement method is as described in the section of Examples.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の数平均分子量（Ｍｎ）は、５０００～１２００００であることが好ましく、８０００～８００００がより好ましく、１２０００～７００００がさらに好ましく、１５０００～６００００が特に好ましく、２００００～５００００が最も好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。
　（メタ）アクリル系共重合体の数平均分子量が上記下限値以上であれば、インクの貯蔵安定性がより良好となる傾向にある。（メタ）アクリル系共重合体の数平均分子量が上記上限値以下であれば、インクの粘度が低くなり、製膜性が良好となる傾向がある。
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の数平均分子量（Ｍｎ）は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によって測定される数平均分子量（ポリスチレン換算）である。具体的な測定方法は実施例の項に記載される通りである。 The number average molecular weight (Mn) of the (meth) acrylic copolymer of the first aspect and the second aspect is preferably 5000 to 120000, more preferably 8000 to 80000, still more preferably 12000 to 70000. 15,000 to 60,000 is particularly preferable, and 20,000 to 50,000 is most preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily.
When the number average molecular weight of the (meth) acrylic copolymer is at least the above lower limit, the storage stability of the ink tends to be better. When the number average molecular weight of the (meth) acrylic copolymer is not more than the above upper limit, the viscosity of the ink tends to be low and the film forming property tends to be good.
The number average molecular weight (Mn) of the (meth) acrylic copolymer of the first aspect and the second aspect is the number average molecular weight (in terms of polystyrene) measured by gel permeation chromatography (GPC). The specific measurement method is as described in the section of Examples.
＜製造方法＞
　第一の態様及び第二の態様の（メタ）アクリル系共重合体は、塊状重合、懸濁重合、乳化重合などの公知の重合方法によって製造することができる。これらの重合方法の中でも、共重合体の取り扱い性が容易な粉体状や球状や粒子状の共重合体が得られやすい点から、塊状重合、懸濁重合が好ましい。 <Manufacturing method>
The (meth) acrylic copolymer of the first aspect and the second aspect can be produced by a known polymerization method such as bulk polymerization, suspension polymerization and emulsion polymerization. Among these polymerization methods, bulk polymerization and suspension polymerization are preferable from the viewpoint that a powder-like polymer, a spherical or particle-like copolymer, which is easy to handle, can be easily obtained.
<懸濁重合による製造方法>
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の懸濁重合による製造方法は、懸濁重合工程と、第一の脱水工程と、洗浄工程と、第二の脱水工程と、乾燥工程とを有することが好ましい。 <Manufacturing method by suspension polymerization>
The method for producing the (meth) acrylic copolymer according to the first aspect and the second aspect by suspension polymerization includes a suspension polymerization step, a first dehydration step, a washing step, and a second dehydration step. , It is preferable to have a drying step.
（懸濁重合工程）
　懸濁重合工程は、上述した単量体（ａ）および単量体（ｂ）と、必要に応じて単量体（ｃ）とを水中に分散させて３官能以上のメルカプタンの存在下、重合し、第一の態様及び第二の態様の（メタ）アクリル系共重合体を得る工程である。
　懸濁重合の方法としては公知の方法を採用できる。懸濁重合の方法としては、例えば、重合温度制御機能と攪拌機能とを有する反応器内にて、単量体（ａ）および単量体（ｂ）と、必要に応じて単量体（ｃ）とを、重合用助剤の存在下、水中で重合させる方法が挙げられる。 (Suspension polymerization step)
In the suspension polymerization step, the above-mentioned monomers (a) and (b) and, if necessary, the monomer (c) are dispersed in water and polymerized in the presence of trifunctional or higher mercaptan. This is a step of obtaining the (meth) acrylic copolymer of the first aspect and the second aspect.
A known method can be adopted as the method of suspension polymerization. As a method of suspension polymerization, for example, in a reactor having a polymerization temperature control function and a stirring function, the monomer (a) and the monomer (b) and, if necessary, the monomer (c) ) And in the presence of a polymerization aid, a method of polymerizing in water can be mentioned.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の製造で使用できる重合用助剤としては、重合開始剤、連鎖移動剤、分散剤、分散助剤などが挙げられる。ただし、少なくとも連鎖移動剤として上述した３官能以上のメルカプタンを用いる。
　重合用助剤として３官能以上のメルカプタンを用いることで、３官能以上のメルカプタン由来の化学構造を有する第一の態様及び第二の態様の（メタ）アクリル系共重合体が得られる。 Examples of the polymerization aid that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect include a polymerization initiator, a chain transfer agent, a dispersant, and a dispersion aid. However, at least the above-mentioned trifunctional or higher functional mercaptan is used as the chain transfer agent.
By using a trifunctional or higher functional mercaptan as a polymerization aid, the (meth) acrylic copolymer of the first aspect and the second aspect having a chemical structure derived from the trifunctional or higher functional mercaptan can be obtained.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の製造で使用できる重合開始剤としては、例えば２，２’－アゾビスイソブチロニトリル、２，２’－アゾビス（２－メチルブチロニトリル）、過酸化ベンゾイル、ラウロイルパーオキサイド、ｔｅｒｔ－ブチルペルオキシ－２－エチルヘキサノエート、ｔｅｒｔ－アミルヒドロキシ－２－エチルヘキサノエート、ｔｅｒｔ－ヘキシルペルオキシ－２－エチルヘキサノエート、１，１，３，３－テトラメチルブチルペルオキシ－２－エチルヘキサノエートなどが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Examples of the polymerization initiator that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect include 2,2'-azobisisobutyronitrile and 2,2'-azobis (2). -Methylbutyronitrile), benzoyl peroxide, lauroyl peroxide, tert-butylperoxy-2-ethylhexanoate, tert-amylhydroxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexanoate , 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate and the like.
These may be used alone or in combination of two or more.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の製造で使用できる連鎖移動剤としては、少なくとも３官能以上のメルカプタンを用いる。
　また、連鎖移動剤として、３官能以上のメルカプタンに加えて、上述した単官能のメルカプタンおよび２官能のメルカプタンの少なくとも一方を併用してもよい。
　さらに、これらメルカプタンに加えて、ジフェニルジスルフィド、ジベンジルジスルフィド、α－メチルスチレンダイマーをさらに併用してもよい。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 As the chain transfer agent that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect, a mercaptan having at least trifunctionality or higher is used.
Further, as the chain transfer agent, in addition to the trifunctional or higher functional mercaptan, at least one of the above-mentioned monofunctional mercaptan and bifunctional mercaptan may be used in combination.
Further, in addition to these mercaptans, diphenyl disulfide, dibenzyl disulfide, and α-methylstyrene dimer may be further used in combination.
These may be used alone or in combination of two or more.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の製造で使用できる分散剤としては、例えば水中で単量体を安定に分散させる界面活性剤が挙げられる。具体的には、メタクリル酸２－スルホエチルナトリウムとメタクリル酸カリウムとメタクリル酸メチルとの共重合体、３－ナトリウムスルホプロピルメタクリレートとメタクリル酸メチルとの共重合体、メタクリル酸ナトリウムとメタクリル酸との共重合体、ポリビニルアルコール、ポリビニルピロリドン、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロースなどが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Examples of the dispersant that can be used in the production of the (meth) acrylic copolymer of the first aspect and the second aspect include a surfactant that stably disperses the monomer in water. Specifically, a copolymer of 2-sulfoethyl sodium methacrylate, potassium methacrylate and methyl methacrylate, a copolymer of 3-sodium sulfopropyl methacrylate and methyl methacrylate, and sodium methacrylate and methacrylic acid. Examples thereof include copolymers, polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose and the like.
These may be used alone or in combination of two or more.
　第一の態様及び第二の態様の（メタ）アクリル系共重合体の製造で使用できる分散助剤としては、例えば硫酸ナトリウム、炭酸ナトリウム、リン酸二水素ナトリウム、リン酸水素二ナトリウム、塩化カリウム、酢酸カルシウム、硫酸マグネシウム、硫酸マンガンなどが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Dispersing aids that can be used in the production of the (meth) acrylic copolymers of the first and second aspects include, for example, sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium chloride. , Calcium acetate, magnesium sulfate, manganese sulfate and the like.
These may be used alone or in combination of two or more.
　懸濁重合により、第一の態様及び第二の態様の（メタ）アクリル系共重合体はスラリーの状態で得られる。スラリーを脱水することで通常は真球に近い形状の（メタ）アクリル系共重合体粒子が得られる。 By suspension polymerization, the (meth) acrylic copolymer of the first aspect and the second aspect is obtained in the state of a slurry. By dehydrating the slurry, (meth) acrylic copolymer particles having a shape close to that of a true sphere can be obtained.
（第一の脱水工程、第二の脱水工程）
　第一の脱水工程は、懸濁重合後のスラリーを脱水機などで脱水して、第一の態様及び第二の態様の（メタ）アクリル系共重合体粒子を反応液から分離する工程である。
　第二の脱水工程は、洗浄工程後の（メタ）アクリル系共重合体粒子を脱水機などで脱水して、（メタ）アクリル系共重合体粒子を洗浄液から分離する工程である。 (First dehydration step, second dehydration step)
The first dehydration step is a step of dehydrating the slurry after suspension polymerization with a dehydrator or the like to separate the (meth) acrylic copolymer particles of the first aspect and the second aspect from the reaction solution. ..
The second dehydration step is a step of dehydrating the (meth) acrylic copolymer particles after the washing step with a dehydrator or the like to separate the (meth) acrylic copolymer particles from the washing liquid.
　各脱水工程には各種の脱水機を使用することができ、例えば遠心脱水機、多孔ベルト上で水を吸引除去する機構の装置などを適宜選択して使用することができる。
　脱水機は、１基を使用してもよいし、同一機種を２基用意して各脱水工程で使用してもよいし、複数の異なる機種の脱水機を使用してもよい。製品品質、設備投資費、生産性、運転コストなどの点から目的に沿う機種を適宜選択することができる。製品品質と生産速度のバランスを重視する場合は、各脱水工程でそれぞれ専用の脱水機を使用することが好ましい。 Various dehydrators can be used in each dehydration step, and for example, a centrifugal dehydrator, a device having a mechanism for sucking and removing water on a perforated belt, and the like can be appropriately selected and used.
One dehydrator may be used, two dehydrators of the same model may be prepared and used in each dehydration step, or a plurality of different models of dehydrators may be used. It is possible to appropriately select a model that suits the purpose in terms of product quality, capital investment cost, productivity, operating cost, and the like. When the balance between product quality and production speed is important, it is preferable to use a dedicated dehydrator in each dehydration process.
（洗浄工程）
　洗浄工程は、反応液から分離された（メタ）アクリル系共重合体粒子を洗浄することである。
　洗浄工程により、（メタ）アクリル系共重合体以外の成分が除去され、第一の態様及び第二の態様の（メタ）アクリル系共重合体が得られる。
　洗浄方法としては、例えば第一の脱水工程で脱水した（メタ）アクリル系共重合体粒子に洗浄液を添加して（メタ）アクリル系共重合体を再度スラリー化させて攪拌混合する方法、洗浄機能を有する脱水機内で脱水工程を行った後に、続けて洗浄液を加えて洗浄する方法などが挙げられる。また、これらの洗浄方法を組み合わせて洗浄を行ってもよい。 (Washing process)
The washing step is to wash the (meth) acrylic copolymer particles separated from the reaction solution.
By the washing step, components other than the (meth) acrylic copolymer are removed, and the (meth) acrylic copolymer of the first aspect and the second aspect is obtained.
As a cleaning method, for example, a method of adding a cleaning liquid to the (meth) acrylic copolymer particles dehydrated in the first dehydration step to re-slurry the (meth) acrylic copolymer and stirring and mixing the (meth) acrylic copolymer, and a cleaning function. After performing the dehydration step in the dehydrator having the above, there is a method of continuously adding a cleaning liquid for cleaning. Moreover, you may perform cleaning by combining these cleaning methods.
　洗浄液は、洗浄工程の目的が達成されるようにその種類や量を選定すればよい。洗浄液としては、例えば水（イオン交換水、蒸留水、精製水など）、ナトリウム塩が溶解した水溶液、任意のｐＨに調整されたバッファー、メタノールなどが挙げられる。 The type and amount of cleaning liquid may be selected so that the purpose of the cleaning process is achieved. Examples of the cleaning liquid include water (ion-exchanged water, distilled water, purified water, etc.), an aqueous solution in which a sodium salt is dissolved, a buffer adjusted to an arbitrary pH, methanol, and the like.
（乾燥工程）
　乾燥工程は、第二の脱水工程後の第一の態様及び第二の態様の（メタ）アクリル系共重合体粒子を乾燥する工程である。
　第二の脱水工程後の（メタ）アクリル系共重合体粒子の表面には水が残留している。また、（メタ）アクリル系共重合体の内部は飽和吸水に近い状態にある。そのため、第一の態様及び第二の態様の（メタ）アクリル系共重合体の含水率をさらに下げるために、乾燥することが好ましい。 (Drying process)
The drying step is a step of drying the (meth) acrylic copolymer particles of the first aspect and the second aspect after the second dehydration step.
Water remains on the surface of the (meth) acrylic copolymer particles after the second dehydration step. Further, the inside of the (meth) acrylic copolymer is in a state close to saturated water absorption. Therefore, in order to further reduce the water content of the (meth) acrylic copolymer of the first aspect and the second aspect, it is preferable to dry.
　乾燥には各種の乾燥機を使用することができ、例えば減圧下で加温して乾燥を行う乾燥機、加温空気を用いて（メタ）アクリル系共重合体粒子を管内空輸しながら同時に乾燥を行う乾燥機、多孔板の下側から加温空気を吹き込み上側の（メタ）アクリル系共重合体粒子を流動させながら乾燥を行う乾燥機などが挙げられる。
　乾燥工程は、乾燥工程後の、第一の態様及び第二の態様の（メタ）アクリル系共重合体の含水率が０．０１～１０質量％となるように行うことが好ましい。 Various dryers can be used for drying. For example, a dryer that heats under reduced pressure to dry, and (meth) acrylic copolymer particles are simultaneously dried while being air-transported in a tube using warm air. Examples thereof include a dryer that performs drying while blowing warm air from the lower side of the perforated plate and flowing the (meth) acrylic copolymer particles on the upper side.
The drying step is preferably performed so that the water content of the (meth) acrylic copolymer of the first aspect and the second aspect after the drying step is 0.01 to 10% by mass.
<塊状重合による製造方法>
　（メタ）アクリル系共重合体の塊状重合による製造方法は、塊状重合工程と、粉砕工程とを有することが好ましい。塊状重合工程と粉砕工程との間に、脱揮工程を有していてもよい。 <Manufacturing method by bulk polymerization>
The method for producing a (meth) acrylic copolymer by bulk polymerization preferably includes a bulk polymerization step and a pulverization step. A devolatile step may be provided between the bulk polymerization step and the pulverization step.
（塊状重合工程）
　塊状重合工程は、上述した単量体（ａ）および単量体（ｂ）と、必要に応じて単量体（ｃ）とを３官能以上のメルカプタンの存在下、重合し、第一の態様及び第二の態様の（メタ）アクリル系共重合体を得る工程である。
　塊状重合の方法としては公知の方法を採用できる。塊状重合の方法としては、例えば、重合温度制御機能を有する反応器内にて、単量体（ａ）および単量体（ｂ）と、必要に応じて単量体（ｃ）とを、重合用助剤の存在下で重合させる方法が挙げられる。 (Bulk polymerization step)
In the bulk polymerization step, the above-mentioned monomers (a) and (b) and, if necessary, the monomer (c) are polymerized in the presence of trifunctional or higher functional mercaptan, and the first embodiment is carried out. And the step of obtaining the (meth) acrylic copolymer of the second aspect.
A known method can be adopted as the bulk polymerization method. As a method of bulk polymerization, for example, the monomer (a) and the monomer (b) and, if necessary, the monomer (c) are polymerized in a reactor having a polymerization temperature control function. Examples thereof include a method of polymerizing in the presence of an auxiliary agent.
　重合用助剤としては、重合開始剤、連鎖移動剤などが挙げられる。ただし、少なくとも連鎖移動剤として上述した３官能以上のメルカプタンを用いる。
　重合開始剤としては、懸濁重合工程の説明において先に例示した重合開始剤が挙げられる。
　連鎖移動剤としては、懸濁重合工程の説明において先に例示した連鎖移動剤が挙げられる。 Examples of the polymerization aid include a polymerization initiator and a chain transfer agent. However, at least the above-mentioned trifunctional or higher functional mercaptan is used as the chain transfer agent.
Examples of the polymerization initiator include the polymerization initiator exemplified above in the description of the suspension polymerization step.
Examples of the chain transfer agent include the chain transfer agents exemplified above in the description of the suspension polymerization step.
　塊状重合工程で用いる反応器の形状は任意である。例えば、実験室レベルの方法としては、両端部を繋ぎ環状にしたゴムチューブを２枚の強化ガラス板で挟み込み、四隅をクリップで止めたガラスセルを反応器として用いることができる。また、工業的に用いられる反応器としては、攪拌機構を有する密閉容器が挙げられる。 The shape of the reactor used in the bulk polymerization step is arbitrary. For example, as a laboratory-level method, a glass cell in which a rubber tube having both ends connected to form an annular shape is sandwiched between two tempered glass plates and the four corners are clipped can be used as a reactor. Further, examples of the reactor used industrially include a closed container having a stirring mechanism.
　重合温度制御機能については、例えば、反応器として前記ガラスセルを用いる場合は、市販の恒温水槽を用いればよい。攪拌機構を有する密閉容器を用いる場合は、反応容器外表面から温度調整された熱媒や冷媒と熱交換させることで温度制御を行うことができる。 Regarding the polymerization temperature control function, for example, when the glass cell is used as a reactor, a commercially available constant temperature water tank may be used. When a closed container having a stirring mechanism is used, the temperature can be controlled by exchanging heat with a heat medium or a refrigerant whose temperature has been adjusted from the outer surface of the reaction container.
（脱揮工程）
　脱揮工程は、塊状重合工程で得られた第一の態様及び第二の態様の（メタ）アクリル系共重合体に含まれる揮発成分（例えば未反応の単量体、水分など）を除去（脱揮）する工程である。
　脱揮方法としては公知の方法を採用できる。脱揮方法としては、例えば、ベント付き押出機を用いて（メタ）アクリル系共重合体を処理する方法などが挙げられる。
　押出機の設定温度は、除去しようとする揮発成分の沸点などを勘案して決定すればよい。 (Devolatile process)
The devolatile step removes volatile components (for example, unreacted monomer, water, etc.) contained in the (meth) acrylic copolymer of the first aspect and the second aspect obtained in the bulk polymerization step (for example, unreacted monomer, moisture, etc.). This is the process of devolatile).
A known method can be adopted as the devolatilization method. Examples of the devolatile method include a method of treating a (meth) acrylic copolymer using an extruder with a vent.
The set temperature of the extruder may be determined in consideration of the boiling point of the volatile component to be removed and the like.
（粉砕工程）
　粉砕工程は、必要に応じて脱揮処理された第一の態様及び第二の態様の（メタ）アクリル系共重合体を、所望の粒子径となるように粉砕する工程である。
　粉砕方法としては、要求される粒子径に応じた任意の粉砕方法を採用できる。
　水中での中和溶解時に水とスラリーを形成させる点から、粉砕後の粒子の最大径は５ｍｍ以下が好ましく、２ｍｍ以下がより好ましい。 (Crushing process)
The pulverization step is a step of pulverizing the (meth) acrylic copolymer of the first aspect and the second aspect, which have been devolatile-treated as necessary, so as to have a desired particle size.
As the pulverization method, any pulverization method according to the required particle size can be adopted.
The maximum diameter of the particles after pulverization is preferably 5 mm or less, more preferably 2 mm or less, from the viewpoint of forming a slurry with water during neutralization and dissolution in water.
＜作用効果＞
　以上説明した本発明の第一の態様及び第二の態様の（メタ）アクリル系共重合体は優れた溶解性と粉体性状をもつことから各種溶剤、特にアルカリ水への溶解性が良好である。さらに本発明の第一の態様及び第二の態様の（メタ）アクリル系共重合体を含有する組成物およびインクは、塗工性に優れており、貯蔵安定性とフィルム印刷における隠ぺい性が優れることから、印刷時にブツや印刷ムラを生じにくい。
　また、本発明の第一の態様及び第二の態様の（メタ）アクリル系共重合体であれば、生産性にも優れる。 <Action effect>
Since the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention described above has excellent solubility and powder properties, it has good solubility in various solvents, especially alkaline water. be. Further, the composition and the ink containing the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention are excellent in coatability, storage stability and concealment in film printing. Therefore, it is unlikely that bumps or uneven printing will occur during printing.
Further, the (meth) acrylic copolymer according to the first aspect and the second aspect of the present invention is also excellent in productivity.
＜用途＞
　本発明の第一の態様及び第二の態様の（メタ）アクリル系共重合体は、例えばインク、塗料の原料として使用できる。特に、水系インクの原料として好適である。 <Use>
The (meth) acrylic copolymer of the first aspect and the second aspect of the present invention can be used as a raw material for, for example, inks and paints. In particular, it is suitable as a raw material for water-based inks.
［（メタ）アクリル系共重合体組成物］
　本発明の（メタ）アクリル系共重合体組成物は、上述した本発明の第一の態様の（メタ）アクリル系共重合体及び第二の態様の（メタ）アクリル系共重合体からなる群から選ばれる１種以上と；水と；塩基性化合物と；を含む。
　（メタ）アクリル系共重合体組成物は、顔料や、水以外の溶剤（以下、「補助溶剤」ともいう。）をさらに含んでいてもよい。
　以下、顔料を含む（メタ）アクリル系共重合体組成物を特に「顔料含有組成物」ともいう。 [(Meta) acrylic copolymer composition]
The (meth) acrylic copolymer composition of the present invention is a group consisting of the (meth) acrylic copolymer of the first aspect of the present invention and the (meth) acrylic copolymer of the second aspect described above. Containing one or more selected from; with water; with a basic compound;
The (meth) acrylic copolymer composition may further contain a pigment and a solvent other than water (hereinafter, also referred to as "auxiliary solvent").
Hereinafter, the (meth) acrylic copolymer composition containing a pigment is also particularly referred to as a “pigment-containing composition”.
　（メタ）アクリル系共重合体の含有量は、（メタ）アクリル系共重合体組成物の総質量に対して１０～６０質量％が好ましく、１５～５０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。（メタ）アクリル系共重合体の含有量が上記下限値以上であれば、製膜性が良好となり、基材への印刷時の質感が良好となる。（メタ）アクリル系共重合体の含有量が上記上限値以下であれば、製膜性が良好となり、各種基材に対する良好な印字性能を発揮する。 The content of the (meth) acrylic copolymer is preferably 10 to 60% by mass, more preferably 15 to 50% by mass, based on the total mass of the (meth) acrylic copolymer composition. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the (meth) acrylic copolymer is at least the above lower limit value, the film-forming property is good and the texture at the time of printing on the substrate is good. When the content of the (meth) acrylic copolymer is not more than the above upper limit value, the film-forming property is good and good printing performance on various substrates is exhibited.
　水の含有量は、（メタ）アクリル系共重合体組成物の総質量に対して２０～８０質量％が好ましく、３０～７０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。水の含有量が上記下限値以上であれば、顔料との混合性が良好となる。水の含有量が上記上限値以下であれば、（メタ）アクリル系重合体を溶解させた後の粘度が低く、他材料との混合性が良好となる。 The water content is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, based on the total mass of the (meth) acrylic copolymer composition. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the water content is at least the above lower limit, the miscibility with the pigment is good. When the water content is not more than the above upper limit, the viscosity after dissolving the (meth) acrylic polymer is low, and the mixing property with other materials is good.
　塩基性化合物は、固体状の（メタ）アクリル系共重合体を中和して、水、または水と補助溶剤との混合溶剤に溶解させる役割を果たす。
　塩基性化合物としては、例えばアルカリ金属水酸化物、アンモニア、アンモニア水、アミン化合物などが挙げられる。
　アルカリ金属水酸化物としては、例えば水酸化リチウム、水酸化ナトリウム、水酸化カリウムなどが挙げられる。
　アミン化合物としては、例えばトリエチルアミン、１－プロピルアミン、ジエチルアミン、トリイソプロピルアミン、ジブチルアミン、アミルアミン、１－オクチルアミン、２－（ジメチルアミノ）エタノール、２－（エチルアミノ）エタノール、２－（ジエチルアミノ）エタノール、１－アミノ－２－プロパノール、２－アミノ－１－プロパノール、３－アミノ－１－プロパノール、１－（ジメチルアミノ）－２－プロパノール、３－（ジメチルアミノ）－１－プロパノール、２－（プロピルアミノ）エタノール、ビス（３－エトキシプロピル）アミン、アミノベンジルアルコール、モルホリン、Ｎ－メチルモルホリン、テトラブチルアンモニウムヒドロキシドなどが挙げられる。
　これらの中でも、使用量あたりのアミン価数が高く中和に必要なアミン量を少なくでき、インクの低ＶＯＣ化が実現できるという点、および印刷物の乾燥後に揮発しやすく、印刷物に残りにくい点から、トリエチルアミン、２－（ジメチルアミノ）エタノールが好ましい。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 The basic compound serves to neutralize the solid (meth) acrylic copolymer and dissolve it in water or a mixed solvent of water and an auxiliary solvent.
Examples of the basic compound include alkali metal hydroxides, ammonia, aqueous ammonia, and amine compounds.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like.
Examples of the amine compound include triethylamine, 1-propylamine, diethylamine, triisopropylamine, dibutylamine, amylamine, 1-octylamine, 2- (dimethylamino) ethanol, 2- (ethylamino) ethanol and 2- (diethylamino). Ethanol, 1-amino-2-propanol, 2-amino-1-propanol, 3-amino-1-propanol, 1- (dimethylamino) -2-propanol, 3- (dimethylamino) -1-propanol, 2- Examples thereof include (propylamino) ethanol, bis (3-ethoxypropyl) amine, aminobenzyl alcohol, morpholin, N-methylmorpholin, tetrabutylammonium hydroxide and the like.
Among these, the amine valence per usage amount is high, the amount of amine required for neutralization can be reduced, the ink can be made low in VOC, and the printed matter is easily volatilized after drying and does not easily remain in the printed matter. , Triethylamine, 2- (dimethylamino) ethanol are preferred.
These may be used alone or in combination of two or more.
　塩基性化合物の含有量は、（メタ）アクリル系共重合体組成物の総質量に対して０．１～１０質量％が好ましく、２～５質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。塩基性化合物の含有量が上記下限値以上であれば、（メタ）アクリル系重合体組成物の溶解性が良好となる。塩基性化合物の含有量が上記上限値以下であれば、印刷後の耐水性が良好となる。 The content of the basic compound is preferably 0.1 to 10% by mass, more preferably 2 to 5% by mass, based on the total mass of the (meth) acrylic copolymer composition. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the basic compound is at least the above lower limit, the solubility of the (meth) acrylic polymer composition is good. When the content of the basic compound is not more than the above upper limit value, the water resistance after printing is good.
　顔料としては、例えば酸化チタン、カーボンブラック、フタロシアニンブルー、フタロシアニングリーン、クロムイエロー、カドミウムイエロー、黄鉛、コバルトブルー、クロムグリーン、コバルトグリーン、ベンジジンイエロー、ジンクホワイトなどが挙げられる。また、市販されている任意の顔料を用いることもできる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Examples of the pigment include titanium oxide, carbon black, phthalocyanine blue, phthalocyanine green, chrome yellow, cadmium yellow, chrome yellow, cobalt blue, chrome green, cobalt green, benzidine yellow, and zinc white. Moreover, any commercially available pigment can also be used.
These may be used alone or in combination of two or more.
　（メタ）アクリル系共重合体組成物が顔料を含む場合、顔料の含有量は、（メタ）アクリル系共重合体組成物の総質量に対して２０～６０質量％が好ましく、２０～５０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。顔料の含有量が上記下限値以上であれば、基材に対する隠ぺい性が向上し、塗膜の発色が良好になる。顔料の含有量が上記上限値以下であれば、均一に顔料が分散したインクを調整することができ、ブツの少ない塗膜となる。 When the (meth) acrylic copolymer composition contains a pigment, the content of the pigment is preferably 20 to 60% by mass, preferably 20 to 50% by mass, based on the total mass of the (meth) acrylic copolymer composition. % Is more preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the pigment is at least the above lower limit value, the concealment property to the substrate is improved and the color development of the coating film is improved. When the content of the pigment is not more than the above upper limit value, the ink in which the pigment is uniformly dispersed can be adjusted, and the coating film has less lumps.
　本発明の（メタ）アクリル系共重合体組成物は、水を溶剤として含むが、必要に応じて水以外の溶剤を補助溶剤として含んでもよい。
　補助溶剤としては、例えばアルコール類、グリコール類、エーテル類、ケトン類、エステル類、カルビトール類のうち水に可溶な有機溶剤などが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 The (meth) acrylic copolymer composition of the present invention contains water as a solvent, but may contain a solvent other than water as an auxiliary solvent, if necessary.
Examples of the auxiliary solvent include water-soluble organic solvents among alcohols, glycols, ethers, ketones, esters, and carbitols.
These may be used alone or in combination of two or more.
　（メタ）アクリル系共重合体組成物が補助溶剤を含む場合、補助溶剤の含有量は、（メタ）アクリル系共重合体組成物の総質量に対して１～４０質量％が好ましく、２～３０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。補助溶剤の含有量が上記下限値以上であれば、（メタ）アクリル系共重合体組成物におけるレベリング性をより向上させることができる。補助溶剤の含有量が上記上限値以下であれば、（メタ）アクリル系共重合体組成物に含まれる揮発性有機化合物（ＶＯＣ）の量を低減できる。 When the (meth) acrylic copolymer composition contains an auxiliary solvent, the content of the auxiliary solvent is preferably 1 to 40% by mass, preferably 2 to 40% by mass, based on the total mass of the (meth) acrylic copolymer composition. 30% by mass is more preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the auxiliary solvent is at least the above lower limit value, the leveling property in the (meth) acrylic copolymer composition can be further improved. When the content of the auxiliary solvent is not more than the above upper limit value, the amount of the volatile organic compound (VOC) contained in the (meth) acrylic copolymer composition can be reduced.
　（メタ）アクリル系共重合体組成物は、例えば水、または水と補助溶剤との混合溶剤に、（メタ）アクリル系共重合体を塩基性化合物とともに溶解させることにより得られる。その際、必要に応じて顔料を配合してもよい。具体的な製造方法としては、通常使用される攪拌機を用いて、（メタ）アクリル系共重合体組成物を構成する成分を混合攪拌する方法が挙げられる。 The (meth) acrylic copolymer composition is obtained by dissolving the (meth) acrylic copolymer together with a basic compound in, for example, water or a mixed solvent of water and an auxiliary solvent. At that time, a pigment may be blended if necessary. Specific examples of the production method include a method of mixing and stirring the components constituting the (meth) acrylic copolymer composition using a normally used stirrer.
　以上説明した本発明の（メタ）アクリル系共重合体組成物は、塗工性に優れ、貯蔵安定性とフィルム印刷における隠ぺい性が優れることから、印刷時にブツ、印刷ムラを生じにくい。 The (meth) acrylic copolymer composition of the present invention described above is excellent in coatability, storage stability and concealment in film printing, and thus is less likely to cause bumps and uneven printing during printing.
［インク］
　本発明のインクは、上述した（メタ）アクリル系共重合体組成物を含む。
　（メタ）アクリル系共重合体組成物が顔料を含まない場合、インクは（メタ）アクリル系共重合体組成物に加えて、顔料をさらに含むことが好ましい。
　（メタ）アクリル系共重合体組成物が顔料含有組成物の場合、顔料含有組成物そのものをインクとしてもよいし、水や補助溶剤でさらに希釈してもよい。
　また、インクは、種々の目的により、必要に応じて補助溶剤、バインダー、その他助剤などをさらに含んでいてもよい。 [ink]
The ink of the present invention contains the above-mentioned (meth) acrylic copolymer composition.
When the (meth) acrylic copolymer composition does not contain a pigment, it is preferable that the ink further contains a pigment in addition to the (meth) acrylic copolymer composition.
When the (meth) acrylic copolymer composition is a pigment-containing composition, the pigment-containing composition itself may be used as an ink, or may be further diluted with water or an auxiliary solvent.
Further, the ink may further contain an auxiliary solvent, a binder, other auxiliary agents and the like, if necessary, for various purposes.
　インクに含まれる本発明の第一の態様及び第二の態様の（メタ）アクリル系共重合体の含有量は、インクの総質量に対して５～３０質量％が好ましく、１０～２５質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。（メタ）アクリル系共重合体の含有量が上記下限値以上であれば、顔料の一次粒子の凝集を抑制することができる。（メタ）アクリル系共重合体の含有量が上記上限値以下であれば、粘度が低く取扱いが容易なインクとなる。 The content of the (meth) acrylic copolymer of the first aspect and the second aspect of the present invention contained in the ink is preferably 5 to 30% by mass, preferably 10 to 25% by mass, based on the total mass of the ink. Is more preferable. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the (meth) acrylic copolymer is at least the above lower limit value, aggregation of the primary particles of the pigment can be suppressed. When the content of the (meth) acrylic copolymer is not more than the above upper limit value, the ink has a low viscosity and is easy to handle.
　インクに含まれる水の含有量は、インクの総質量に対して２０～６０質量％が好ましく２５～５０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。水の含有量が上記下限値以上であれば、粘度の低く印刷が容易なインクとなる。水の含有量が上記上限値以下であれば、印刷物の乾燥性が良好となる。 The content of water contained in the ink is preferably 20 to 60% by mass, more preferably 25 to 50% by mass, based on the total mass of the ink. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the water content is at least the above lower limit value, the ink has a low viscosity and is easy to print. When the water content is not more than the above upper limit value, the dryness of the printed matter is good.
　インクに含まれる塩基性化合物の含有量は、インクの総質量に対して０．１～１０質量％が好ましく、２～５質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。塩基性化合物の含有量が上記下限値以上であれば、インクの製膜性が良好となる。塩基性化合物の含有量が上記上限値以下であれば、耐水性が良好な画像を形成することができる。 The content of the basic compound contained in the ink is preferably 0.1 to 10% by mass, more preferably 2 to 5% by mass, based on the total mass of the ink. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the basic compound is at least the above lower limit value, the film forming property of the ink is good. When the content of the basic compound is not more than the above upper limit value, an image having good water resistance can be formed.
　顔料としては、（メタ）アクリル系共重合体組成物の説明において先に例示した顔料が挙げられる。
　インクに含まれる顔料の含有量は、インクの総質量に対して１０～５０質量％が好ましく、２０～４０質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。顔料の含有量が上記下限値以上であれば、基材の隠ぺい性に優れるインクとなる。顔料の含有量が上記上限値以下であれば、印刷時の凝集物発生が抑制され、色ムラの少ないインクとなる。 Examples of the pigment include the pigments exemplified above in the description of the (meth) acrylic copolymer composition.
The content of the pigment contained in the ink is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, based on the total mass of the ink. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the pigment is at least the above lower limit value, the ink has excellent hiding power of the base material. When the content of the pigment is not more than the above upper limit value, the generation of agglomerates during printing is suppressed, and the ink has less color unevenness.
　本発明のインクは、水を溶剤として含むが、必要に応じて水以外の溶剤を補助溶剤として含んでもよい。
　補助溶剤としては、（メタ）アクリル系共重合体組成物の説明において先に例示した補助溶剤が挙げられる。
　インクが補助溶剤を含む場合は、補助溶剤の含有量は、インクの総質量に対して０．１～３０質量％が好ましく、１～２５質量％がより好ましい。これらの数値範囲の下限値および上限値は任意に組み合わせることができる。補助溶剤の含有量が上記下限値以上であれば、水系インクにおけるレベリング性をより向上させることができる。補助溶剤の含有量が上記上限値以下であれば、インクに含まれる揮発性有機化合物（ＶＯＣ）の量を低減できる。 The ink of the present invention contains water as a solvent, but may contain a solvent other than water as an auxiliary solvent, if necessary.
Examples of the auxiliary solvent include the auxiliary solvent exemplified above in the description of the (meth) acrylic copolymer composition.
When the ink contains an auxiliary solvent, the content of the auxiliary solvent is preferably 0.1 to 30% by mass, more preferably 1 to 25% by mass, based on the total mass of the ink. The lower and upper limits of these numerical ranges can be combined arbitrarily. When the content of the auxiliary solvent is at least the above lower limit value, the leveling property in the water-based ink can be further improved. When the content of the auxiliary solvent is not more than the above upper limit value, the amount of the volatile organic compound (VOC) contained in the ink can be reduced.
　本発明のインクは、インクの基材密着力を補う目的でバインダーを含んでいてもよい。
　バインダーとしては、例えばウレタンディスパージョン（ＰＵＤ）、ウレタン－アクリル複合ディスパージョン（ＰＵＡ）、アクリルエマルション、ポリエステルディスパージョン、ポリオレフィンディスパージョン、ポリオレフィン－アクリル複合ディスパージョン、ポリオレフィン－ポリエステルディスパージョンなどが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 The ink of the present invention may contain a binder for the purpose of supplementing the substrate adhesion of the ink.
Examples of the binder include urethane dispersion (PUD), urethane-acrylic composite dispersion (PUA), acrylic emulsion, polyester dispersion, polyolefin dispersion, polyolefin-acrylic composite dispersion, polyolefin-polyester dispersion and the like.
These may be used alone or in combination of two or more.
　その他の助剤としては、例えば消泡剤、レベリング剤や、顔料分散剤、製膜助剤、密着性付与剤などが挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 Examples of other auxiliaries include defoaming agents, leveling agents, pigment dispersants, film-forming auxiliaries, and adhesion-imparting agents.
These may be used alone or in combination of two or more.
　インクは、例えば（メタ）アクリル系共重合体組成物に、顔料と、必要に応じて補助溶剤、バインダーおよびその他助剤の１つ以上を加え、混合することにより得られる。その際、必要に応じて、顔料分散処理を行ってもよい。また、必要に応じて水でさらに希釈してもよい。
　顔料分散処理の方法としては、市販のロッキングシェーカーや、遊星ビーズミル、バッチ式攪拌式ビーズミル、連続式攪拌式ビーズミルなどを用いた、任意の分散処理方法を採用できる。 The ink is obtained, for example, by adding a pigment and, if necessary, one or more of an auxiliary solvent, a binder and other auxiliary agents to a (meth) acrylic copolymer composition and mixing them. At that time, if necessary, a pigment dispersion treatment may be performed. Further, it may be further diluted with water if necessary.
As a method for the pigment dispersion treatment, an arbitrary dispersion treatment method using a commercially available rocking shaker, a planetary bead mill, a batch type stirring type bead mill, a continuous stirring type bead mill, or the like can be adopted.
　以上説明した本発明のインクは、塗工性に優れており、貯蔵安定性とフィルム印刷における隠ぺい性が優れることから、印刷時にブツや印刷ムラを生じにくい。 The ink of the present invention described above is excellent in coatability, storage stability and concealment in film printing, and thus is less likely to cause bumps or uneven printing during printing.
　以下、本発明を実施例により具体的に説明するが、本発明はこれらに限定されるものではない。
　以下の実施例および比較例における各種測定および評価方法は、以下の通りである。
　なお、以下の説明において、特に断りがない限り「部」は質量部を意味し、「％」は質量％を意味する。 Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.
Various measurement and evaluation methods in the following Examples and Comparative Examples are as follows.
In the following description, unless otherwise specified, "parts" means parts by mass and "%" means% by mass.
［測定・評価方法］
＜二次ガラス転移温度（Ｔｇ）の測定＞
　示差走査熱量計（セイコーインスツル株式会社製、「ＥＸＳＴＡＲ　ＤＳＣ－６２００」）を用い、下記温度走査条件にて（メタ）アクリル系共重合体５ｍｇに対して昇降温操作を行った。下記温度走査条件の工程（３）で測定されたＤＳＣデータを、横軸に温度（℃）、縦軸にＤＳＣ測定値（ｍＷ）をプロットした際、グラフの傾きの変化率が０となる点のうち低温側の点について引いた接線と、グラフの傾きの変化率が最大となる点（変曲点）の接線の交点に対応する温度（℃）を（メタ）アクリル系共重合体の二次ガラス転移温度（Ｔｇ）とした。
（温度走査条件）
・工程（１）：－１０℃で５分間安定後、１１０℃まで昇温する。
・工程（２）：－１０℃まで冷却する。
・工程（３）：１１０℃まで再度昇温する。
・工程（４）：室温まで冷却する。
・昇温速度　：＋１０℃／分。
・降温速度　：－１０℃／分。 [Measurement / evaluation method]
<Measurement of secondary glass transition temperature (Tg)>
Using a differential scanning calorimeter (“EXSTAR DSC-6200” manufactured by Seiko Instruments Inc.), a temperature increase / decrease operation was performed on 5 mg of the (meth) acrylic copolymer under the following temperature scanning conditions. When the DSC data measured in step (3) under the following temperature scanning conditions is plotted with the temperature (° C.) on the horizontal axis and the DSC measured value (mW) on the vertical axis, the rate of change in the slope of the graph becomes 0. Of the (meth) acrylic copolymer, the temperature (° C) corresponding to the intersection of the tangent line drawn for the point on the low temperature side and the tangent line of the point (conversion point) where the rate of change in the slope of the graph is maximum is set. The next glass transition temperature (Tg) was used.
(Temperature scanning conditions)
Step (1): After stabilizing at −10 ° C. for 5 minutes, the temperature is raised to 110 ° C.
-Step (2): Cool to -10 ° C.
-Step (3): The temperature is raised again to 110 ° C.
-Step (4): Cool to room temperature.
・ Temperature rise rate: + 10 ° C / min.
・ Temperature drop rate: -10 ° C / min.
＜酸価の測定＞
　（メタ）アクリル系共重合体約０．５ｇをビーカーに精秤し（Ａ（ｇ））、トルエンとエタノールの混合溶液（質量比１：１）５０ｍＬを加えた。フェノールフタレイン数滴を加え、０．０５規定のＫＯＨ溶液（溶媒：エタノール）にて滴定した。（滴定量＝Ｂ（ｍＬ）、ＫＯＨ溶液の力価＝ｆ）。ブランク測定を同様に行い（滴定量＝Ｃ（ｍＬ））、以下の式に従って算出した。
　酸価（ｍｇＫＯＨ／ｇ）＝｛（Ｂ－Ｃ）×０．０５×５６．１１×ｆ｝／Ａ <Measurement of acid value>
About 0.5 g of the (meth) acrylic copolymer was precisely weighed in a beaker (A (g)), and 50 mL of a mixed solution of toluene and ethanol (mass ratio 1: 1) was added. A few drops of phenolphthalein were added, and the mixture was titrated with a KOH solution (solvent: ethanol) of 0.05N. (Titration = B (mL), titer of KOH solution = f). The blank measurement was performed in the same manner (titration = C (mL)), and the calculation was performed according to the following formula.
Acid value (mgKOH / g) = {(BC) x 0.05 x 56.11 x f} / A
＜重量平均分子量（Ｍｗ）および数平均分子量（Ｍｎ）の測定＞
　（メタ）アクリル系共重合体の重量平均分子量（Ｍｗ）および数平均分子量（Ｍｎ）は、ゲルパーミエーショングロマトグラフィー（ＧＰＣ）により測定し、標準ポリスチレンの検量線を用いてポリスチレン換算した値として算出した。ＧＰＣの測定条件は以下の通りである。
（ＧＰＣ測定条件）
・装置：東ソー株式会社製の「ＨＬＣ－８２２０ＧＰＣ」。
・カラム：東ソー株式会社製の「ＴＳＫｇｅｌ　Ｇ５０００ＨＸＬ（７．８ｍｍφ×３００ｍｍ）」と「ＧＭＨＸＬ－Ｌ（７．８ｍｍφ×３００ｍｍ）」を直列に連結したもの。
・溶離液：テトラヒドロフラン。
・試料濃度：０．４％。
・測定温度：４０℃。
・注入量：１００μＬ。
・流量：１．０ｍＬ／分。
・検出器：ＲＩ（装置内蔵）、ＵＶ（東ソー　ＵＶ－８２２０）。 <Measurement of weight average molecular weight (Mw) and number average molecular weight (Mn)>
The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth) acrylic copolymer were measured by gel permeation glomatography (GPC) and converted into polystyrene using a standard polystyrene calibration curve. Calculated. The measurement conditions of GPC are as follows.
(GPC measurement conditions)
-Device: "HLC-8220GPC" manufactured by Tosoh Corporation.
-Column: "TSKgel G5000HXL (7.8 mmφ x 300 mm)" and "GMHXL-L (7.8 mmφ x 300 mm)" manufactured by Tosoh Corporation are connected in series.
-Eluent: Tetrahydrofuran.
-Sample concentration: 0.4%.
-Measurement temperature: 40 ° C.
-Injection amount: 100 μL.
-Flow rate: 1.0 mL / min.
-Detector: RI (built-in device), UV (Tosoh UV-8220).
＜含水率の測定＞
　（メタ）アクリル系共重合体の含水率は、（メタ）アクリル系共重合体を１０５℃で２時間乾燥した場合の含水率を０％として、１０５℃で２時間乾燥した時の乾燥前後の（メタ）アクリル系共重合体の重量の乾燥減量から算出した。 <Measurement of water content>
The water content of the (meth) acrylic copolymer is 0% when the (meth) acrylic copolymer is dried at 105 ° C. for 2 hours, and before and after drying when the (meth) acrylic copolymer is dried at 105 ° C. for 2 hours. It was calculated from the dry weight loss of the (meth) acrylic copolymer.
＜アルカリ水への溶解性の評価＞
　水６５．５ｇおよび（メタ）アクリル系共重合体３０．０ｇを攪拌子とともにガラス瓶（柏洋硝子株式会社製、「Ｍ－２２５」）に投入し、蓋をして、３０℃に調温された水浴中で１０分間攪拌してスラリーとした。得られたスラリーに、２－（ジメチルアミノ）エタノール４．５ｇを加え、さらに３０℃で３時間攪拌した後の溶解性を溶液の状態を目視にて確認した。溶液中に沈殿物がある場合は追加で３時間攪拌を行い、以下の評価基準にてアルカリ水への溶解性を評価した。
　Ａ：最初の３時間の攪拌後、沈殿物が目視で確認されず、溶解性に優れている。
　Ａ－：最初の３時間の攪拌後は沈殿物が目視で確認されたが、追加で３時間攪拌することで沈殿物が消失しており、溶解性に優れている。
　Ｂ：６時間攪拌後も明らかに不溶物が沈殿しており、溶解性が悪い。 <Evaluation of solubility in alkaline water>
65.5 g of water and 30.0 g of the (meth) acrylic copolymer were put into a glass bottle (“M-225” manufactured by Kashiwayo Glass Co., Ltd.) together with a stirrer, covered, and the temperature was adjusted to 30 ° C. The mixture was stirred in a water bath for 10 minutes to obtain a slurry. After adding 4.5 g of 2- (dimethylamino) ethanol to the obtained slurry and further stirring at 30 ° C. for 3 hours, the solubility of the solution was visually confirmed. If there was a precipitate in the solution, it was stirred for an additional 3 hours, and its solubility in alkaline water was evaluated according to the following evaluation criteria.
A: After stirring for the first 3 hours, no precipitate was visually confirmed and the solubility was excellent.
A-: The precipitate was visually confirmed after stirring for the first 3 hours, but the precipitate disappeared by stirring for an additional 3 hours, and the solubility was excellent.
B: Insoluble matter is clearly precipitated even after stirring for 6 hours, and the solubility is poor.
＜貯蔵安定性および隠ぺい性の評価＞
（（メタ）アクリル系共重合体組成物の調製）
　水６５．５ｇおよび（メタ）アクリル系共重合体３０．０ｇを攪拌子とともにガラス瓶（柏洋硝子株式会社製、「Ｍ－２２５」）に投入し、蓋をして、室温で１０分間攪拌してスラリーとした。得られたスラリーに、２－（ジメチルアミノ）エタノール４．５ｇを加え、さらに６０℃の水浴につけ、溶け残りがなくなるまで攪拌して、（メタ）アクリル系共重合体の濃度が３０％である（メタ）アクリル系共重合体組成物を得た。 <Evaluation of storage stability and concealment>
(Preparation of (meth) acrylic copolymer composition)
65.5 g of water and 30.0 g of the (meth) acrylic copolymer were put into a glass bottle (“M-225” manufactured by Kashiwayo Glass Co., Ltd.) together with a stirrer, covered, and stirred at room temperature for 10 minutes. Was made into a slurry. To the obtained slurry, 4.5 g of 2- (dimethylamino) ethanol was added, and the mixture was further immersed in a water bath at 60 ° C. and stirred until there was no undissolved residue. The concentration of the (meth) acrylic copolymer was 30%. A (meth) acrylic copolymer composition was obtained.
（インクの調製）
　得られた（メタ）アクリル系共重合体組成物５０ｇ、酸化チタンＣＲ－９０（石原産業株式会社製）３０ｇ、２－プロパノール２０ｇ、ガラスビーズ６０ｇを容器内で混合した後、ロッキングシェーカーにて１時間分散処理を行った。次いで、得られた混合物からガラスビーズを除去し、顔料ペーストを得た。
　得られた顔料ペースト６０ｇに対して、２－プロパノール１１ｇ、水１３ｇを添加し希釈して、水系インクを得た。得られた水系インクを用いて、インクの貯蔵安定性と印刷物の隠ぺい性の評価を行った。 (Ink preparation)
After mixing 50 g of the obtained (meth) acrylic copolymer composition, 30 g of titanium oxide CR-90 (manufactured by Ishihara Sangyo Co., Ltd.), 20 g of 2-propanol, and 60 g of glass beads in a container, 1 using a locking shaker. Time distribution processing was performed. Then, the glass beads were removed from the obtained mixture to obtain a pigment paste.
To 60 g of the obtained pigment paste, 11 g of 2-propanol and 13 g of water were added and diluted to obtain a water-based ink. Using the obtained water-based ink, the storage stability of the ink and the hiding property of the printed matter were evaluated.
（貯蔵安定性の評価）
　インクを室温で３日間静置し、顔料の沈降の有無を目視にて確認し、以下の評価基準にて貯蔵安定性を評価した。
　Ａ：３日経過時でもインク中で顔料が分散状態にある。
　Ｂ：３日経過時にインク中の顔料の一部または全部が沈殿している。 (Evaluation of storage stability)
The ink was allowed to stand at room temperature for 3 days, the presence or absence of pigment precipitation was visually confirmed, and the storage stability was evaluated according to the following evaluation criteria.
A: The pigment is still dispersed in the ink even after 3 days have passed.
B: After 3 days, part or all of the pigment in the ink has settled.
（隠ぺい性の評価）
　グラビア印刷機（ＲＫ　ＰＲＩＮＴＣＯＡＴ　ＩＮＳＴＲＵＭＥＮＴＳ社製、「ＧＰ－１００」）にインクをセットして、印刷を行った。印刷時の版プレートは１５０線／インチのものを使用した。また、印刷対象の基材としては、プロピレンフィルム（東洋紡株式会社製、「パイレン（登録商標）フィルムＯＴ　Ｐ２１０８」）を使用した。
　印刷後の塗膜について、分光測色計（コニカミノルタ株式会社、「ＣＭ－５」）を用いて、透過光の色差を測定した。その後、Ｌ＊値（明度）の実測値から１００を減ずることにより△Ｌ値を求め、以下の評価基準にて隠ぺい性を評価した。△Ｌ値が小さいほど、印刷物の隠ぺい性に優れることを意味する。
　Ａ：△Ｌ値≦－２２．５。
　Ｂ：△Ｌ値＞－２２．５。 (Evaluation of concealment)
Ink was set in a gravure printing machine (“GP-100” manufactured by RK PRINTCOAT INSTRUMENTS), and printing was performed. The plate plate used for printing was 150 lines / inch. A propylene film (“Pyrene (registered trademark) film OT P2108” manufactured by Toyobo Co., Ltd.) was used as the base material to be printed.
With respect to the coating film after printing, the color difference of transmitted light was measured using a spectrocolorimeter (Konica Minolta Co., Ltd., "CM-5"). Then, the ΔL value was obtained by subtracting 100 from the measured value of the L * value (brightness), and the concealment was evaluated according to the following evaluation criteria. The smaller the ΔL value, the better the concealment of the printed matter.
A: ΔL value ≦ -22.5.
B: ΔL value> -22.5.
［分散剤（１）の製造］
　攪拌機、冷却管、温度計を備えた重合装置に、脱イオン水１２３０ｇ、メタクリル酸２－スルホエチルナトリウム６０ｇ、メタクリル酸カリウム１０ｇ、メタクリル酸メチル１２ｇを加えて攪拌し、重合装置内を窒素置換しながら、重合温度５０℃に昇温し、重合開始剤として２，２’－アゾビス（２－メチルプロピオンアミジン）二塩酸塩０．０８ｇを添加し、さらに重合温度６０℃に昇温した。重合開始剤の添加と同時に、滴下ポンプを使用して、メタクリル酸メチルを０．２４ｇ／ｍｉｎの速度で７５分間連続的に滴下し、重合温度６０℃で６時間保持した後、室温に冷却して分散剤（１）を得た。得られた分散剤（１）の固形分は７．５％あった。 [Manufacturing of dispersant (1)]
To a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer, 1230 g of deionized water, 60 g of 2-sulfoethyl sodium methacrylate, 10 g of potassium methacrylate, and 12 g of methyl methacrylate were added and stirred to replace the inside of the polymerization apparatus with nitrogen. However, the polymerization temperature was raised to 50 ° C., 0.08 g of 2,2'-azobis (2-methylpropionamidine) dihydrochloride as a polymerization initiator was added, and the polymerization temperature was further raised to 60 ° C. Simultaneously with the addition of the polymerization initiator, methyl methacrylate was continuously added dropwise at a rate of 0.24 g / min for 75 minutes using a dropping pump, maintained at a polymerization temperature of 60 ° C. for 6 hours, and then cooled to room temperature. The dispersant (1) was obtained. The solid content of the obtained dispersant (1) was 7.5%.
［実施例１］
　攪拌機、冷却管、温度計を備えた重合装置中に、メタクリル酸メチル４０部、メタクリル酸ｎ－ブチル４０部、アクリル酸ｎ－ブチル５部、メタクリル酸１５部、トリメチロールプロパントリメタクリレート１．２部を均一に溶解した単量体混合物と、２，２’－アゾビス（２－メチルブチロニトリル）０．４部と、３－メルカプトプロピオン酸２－エチルヘキシル２部、トリメチロールプロパントリス（３－メルカプトプロピオネート）２部、ペンタエリスリトールテトラキス（チオグリコレート）２部を加え、均一になるまで攪拌混合した。さらに、純水１６０部、硫酸ナトリウム０．１部、分散剤（１）０．６部を均一混合したものを加え、攪拌しながら窒素置換を行った。その後、８０℃にフラスコ内温度を制御して懸濁重合を開始し、重合発熱のピークを検出した後、９０℃で３０分処理し、スラリー状の（メタ）アクリル系共重合体を得た（懸濁重合工程）。
　重合後、釜内を常温まで冷却し、生成したスラリーを遠心分離式脱水機にて脱水した（第一の脱水工程）。
　得られた（メタ）アクリル系共重合体と、洗浄液として純水を質量比（（メタ）アクリル系共重合体：洗浄液）が１：２となるように洗浄用槽に投入し、２０分間攪拌混合して洗浄を行った後（洗浄工程）、遠心分離式脱水機にて脱水した（第二の脱水工程）。
　脱水後、脱水された（メタ）アクリル系共重合体を４０℃に内温設定された流動槽式乾燥機に投入し、（メタ）アクリル系共重合体粒子の含水率が１０％以下になるように乾燥した（乾燥工程）。
　得られた粒子状の固体の（メタ）アクリル系共重合体粒子について、二次ガラス転移温度（Ｔｇ）、酸価、重量平均分子量（Ｍｗ）および数平均分子量（Ｍｎ）を測定し、アルカリ水への溶解性を評価した。また、上述した方法により水系インクを調製し、インクの貯蔵安定性と印刷物の隠ぺい性を評価した。結果を表１に示す。 [Example 1]
In a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer, 40 parts of methyl methacrylate, 40 parts of n-butyl methacrylate, 5 parts of n-butyl acrylate, 15 parts of methacrylic acid, and trimethylolpropane trimethacrylate 1.2. A monomer mixture in which parts are uniformly dissolved, 0.4 parts of 2,2'-azobis (2-methylbutyronitrile), 2 parts of 2-ethylhexyl 3-mercaptopropionic acid, and trimethyl propanthris (3-parts). Two parts of mercaptopropionate) and two parts of pentaerythritol tetrakis (thioglycolate) were added, and the mixture was stirred and mixed until uniform. Further, 160 parts of pure water, 0.1 part of sodium sulfate, and 0.6 part of the dispersant (1) were uniformly mixed, and nitrogen substitution was performed while stirring. Then, suspension polymerization was started by controlling the temperature in the flask to 80 ° C., and after detecting the peak of polymerization heat generation, the treatment was performed at 90 ° C. for 30 minutes to obtain a slurry-like (meth) acrylic copolymer. (Suspension polymerization step).
After the polymerization, the inside of the kettle was cooled to room temperature, and the generated slurry was dehydrated by a centrifugal dehydrator (first dehydration step).
The obtained (meth) acrylic copolymer and pure water as a cleaning liquid are put into a cleaning tank so that the mass ratio ((meth) acrylic copolymer: cleaning liquid) is 1: 2, and the mixture is stirred for 20 minutes. After mixing and washing (washing step), dehydration was performed with a centrifugal dehydrator (second dehydration step).
After dehydration, the dehydrated (meth) acrylic copolymer is put into a flow tank type dryer whose internal temperature is set to 40 ° C., and the water content of the (meth) acrylic copolymer particles becomes 10% or less. Dry (drying process).
For the obtained particulate solid (meth) acrylic copolymer particles, the secondary glass transition temperature (Tg), acid value, weight average molecular weight (Mw) and number average molecular weight (Mn) were measured, and alkaline water was measured. Solubility in was evaluated. In addition, water-based ink was prepared by the above-mentioned method, and the storage stability of the ink and the hiding property of the printed matter were evaluated. The results are shown in Table 1.
［実施例２、３、５、６、比較例１～７］
　表１、２に示す配合組成とした以外は、実施例１と同様にして粒子状の固体の（メタ）アクリル系共重合体粒子を製造し、各種測定および評価を行った。結果を表１に示す。 [Examples 2, 3, 5, 6, Comparative Examples 1 to 7]
Particle-like solid (meth) acrylic copolymer particles were produced in the same manner as in Example 1 except for the compounding compositions shown in Tables 1 and 2, and various measurements and evaluations were performed. The results are shown in Table 1.
［実施例４］
　温度計を備えたガラスセル中に、メタクリル酸メチル７０部、アクリル酸ｎ－ブチル５部、アクリル酸２－エチルヘキシル１２部、メタクリル酸１３部、トリメチロールプロパントリアクリレート１．２部、ｔｅｒｔ－ブチルペルオキシ－２－エチルヘキサノエート（日油株式会社製、「パーブチルＯ」）０．４部、３－メルカプトプロピオン酸２－エチルヘキシル４部、ペンタエリスリトールテトラキス（チオグリコレート）２部、の均一混合物を投入し、密閉した後、水槽中で８３℃にガラスセル内温度を制御して塊状重合を開始し、重合発熱のピークを検出した後、９０℃で３０分処理し、塊状の固体の（メタ）アクリル系共重合体を得た（塊状重合工程）。
　重合後、ガラスセル内を常温まで冷却した。塊状の固体の（メタ）アクリル系共重合体をセルから取り外し、サニタリークラッシャーＳＣ－０１（三庄インダストリー株式会社製）にて粉砕後、目開き２ｍｍのメッシュの上で振とうし、通過分を回収し、粒子状の固体の（メタ）アクリル系共重合体を得た（粉砕工程）。
　得られた粒子状の固体の（メタ）アクリル系共重合体について、二次ガラス転移温度（Ｔｇ）、酸価、重量平均分子量（Ｍｗ）および数平均分子量（Ｍｎ）を測定し、アルカリ水への溶解性を評価した。また、上述した方法により水系インクを調製し、インクの貯蔵安定性と印刷物の隠ぺい性を評価した。結果を表１に示す。 [Example 4]
In a glass cell equipped with a thermometer, 70 parts of methyl methacrylate, 5 parts of n-butyl acrylate, 12 parts of 2-ethylhexyl acrylate, 13 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, and tert-butyl. Uniform mixture of 0.4 part of peroxy-2-ethylhexanoate (manufactured by Nichiyu Co., Ltd., "Perbutyl O"), 4 parts of 2-ethylhexyl 3-mercaptopropionate, and 2 parts of pentaerythritol tetrakis (thioglycolate). After charging and sealing, the temperature inside the glass cell was controlled to 83 ° C. in a water tank to start bulk polymerization, and after detecting the peak of polymerization heat generation, the bulk polymerization was treated at 90 ° C. for 30 minutes. A (meth) acrylic copolymer was obtained (bulk polymerization step).
After the polymerization, the inside of the glass cell was cooled to room temperature. The lumpy solid (meth) acrylic copolymer is removed from the cell, crushed with a sanitary crusher SC-01 (manufactured by Misho Industry Co., Ltd.), and then shaken on a mesh with an opening of 2 mm to pass the passage. It was recovered to obtain a solid (meth) acrylic copolymer in the form of particles (pulverization step).
The secondary glass transition temperature (Tg), acid value, weight average molecular weight (Mw) and number average molecular weight (Mn) of the obtained particulate solid (meth) acrylic copolymer were measured, and the mixture was added to alkaline water. The solubility of was evaluated. In addition, water-based ink was prepared by the above-mentioned method, and the storage stability of the ink and the hiding property of the printed matter were evaluated. The results are shown in Table 1.
［実施例５］
　実施例４で得られた粒子状の固体の（メタ）アクリル系共重合体を、目開き１ｍｍのメッシュ上で５分間振とうし、通過分を回収し、粒子状の固体の（メタ）アクリル系共重合体を得た。 [Example 5]
The particulate solid (meth) acrylic copolymer obtained in Example 4 was shaken on a mesh having an opening of 1 mm for 5 minutes, and the passage was collected to collect the particulate solid (meth) acrylic. A system copolymer was obtained.
［実施例６］
　実施例４で得られた粒子状の（メタ）アクリル系共重合体を、目開き７５０μｍのメッシュ上で５分間振とうし、通過分を回収し、粒子状の固体の（メタ）アクリル系共重合体を得た。 [Example 6]
The particulate (meth) acrylic copolymer obtained in Example 4 was shaken on a mesh having an opening of 750 μm for 5 minutes, and the passage was collected to collect the particulate (meth) acrylic copolymer. A polymer was obtained.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表中の略号は以下の通りである。また、表中の空欄は、その成分が配合されていないこと（配合量０部）を意味する。
・ＭＭＡ：メタクリル酸メチル。
・ｎ－ＢＭＡ：メタクリル酸ｎ－ブチル。
・ｎ－ＢＡ：アクリル酸ｎ－ブチル。
・２－ＥＨＡ：アクリル酸２－エチルヘキシル。
・ＩＢＸＭＡ：メタクリル酸イソボルニル。
・ＭＡＡ：メタクリル酸。
・ＴＭＰＴＭＡ：トリメチロールプロパントリメタクリレート。
・ＨＤＤＡ：１，６－ヘキサンジオールジアクリレート。
・ＴＭＰＴＡ：トリメチロールプロパントリアクリレート。
・ＥＨＭＰ：３－メルカプトプロピオン酸２－エチルヘキシル。
・ＥＧＭＰ：エチレングリコールビス（３－メルカプトプロピオネート）。
・ＴＭＰＭＰ：トリメチロールプロパントリス（３－メルカプトプロピオネート）。
・ＰＥＭＰ：ペンタエリスリトールテトラキス（３－メルカプトプロピオネート）。
・ＰＥＴＧ：ペンタエリスリトールテトラキス（チオグリコレート）。
・ＡＭＢＮ：２，２’－アゾビス（２－メチルブチロニトリル）。
・パーブチルＯ：ｔｅｒｔ－ブチルペルオキシ－２－エチルヘキサノエート。
　なお、ＩＢＸＭＡは単量体（ａ）の代替品（単量体（ａ’））である。 The abbreviations in the table are as follows. Further, a blank in the table means that the component is not blended (blending amount is 0 parts).
-MMA: Methyl methacrylate.
-N-BMA: n-butyl methacrylate.
-N-BA: n-butyl acrylate.
2-EHA: 2-ethylhexyl acrylate.
IBXMA: Isobornyl methacrylate.
-MAA: Methacrylic acid.
-TMPTMA: Trimethylolpropane Trimethacrylate.
HDDA: 1,6-hexanediol diacrylate.
-TMPTA: Trimethylolpropane triacrylate.
EHMP: 2-ethylhexyl 3-mercaptopropionate.
-EGMP: Ethylene glycol bis (3-mercaptopropionate).
-TMPMP: Trimethylolpropanetris (3-mercaptopropionate).
-PEMP: Pentaerythritol tetrakis (3-mercaptopropionate).
-PETG: Pentaerythritol tetrakis (thioglycolate).
-AMBN: 2,2'-azobis (2-methylbutyronitrile).
-Perbutyl O: tert-butylperoxy-2-ethylhexanoate.
IBXMA is a substitute for the monomer (a) (monomer (a')).
　表１の結果から明らかなように、各実施例で得られた（メタ）アクリル系共重合体は、アルカリ水への溶解性が良好であった。また、これら（メタ）アクリル系共重合体を含むインクは、貯蔵安定性が良好であり、フィルム印刷における印刷物の隠ぺい性にも優れていた。 As is clear from the results in Table 1, the (meth) acrylic copolymer obtained in each example had good solubility in alkaline water. In addition, the ink containing these (meth) acrylic copolymers has good storage stability and excellent concealment of printed matter in film printing.
　一方、表２の結果から明らかなように、３官能以上のメルカプタン由来の化学構造を有さず、代わりに単官能のメルカプタン由来の化学構造を有する（メタ）アクリル系共重合体を使用した比較例１、２の場合、インクの貯蔵安定性と印刷物の隠ぺい性が悪かった。
　３官能以上のメルカプタン由来の化学構造を有さず、代わりに単官能のメルカプタン由来の化学構造を有するものの、単量体（ｃ２）由来の構成単位としてＨＤＤＡ（１，６－ヘキサンジオールジアクリレート）由来の構成単位を有する比較例３の（メタ）アクリル系共重合体は、アルカリ水への溶解性が悪かった。また、比較例３の場合、（メタ）アクリル系共重合体組成物は得られたものの粘度が非常に高く、顔料の分散処理を行うことができなかったため、インクの貯蔵安定性と印刷物の隠ぺい性の評価を行うことができなかった。
　３官能以上のメルカプタン由来の化学構造を有さず、代わりに単官能のメルカプタン由来の化学構造または２官能のメルカプタン由来の化学構造を有するものの、その割合が比較例１、２の場合と比べて少ない比較例４、５の（メタ）アクリル系共重合体は、溶離液に溶解せず、ＧＰＣ測定を行うことができなかった。また、アルカリ水への溶解性が悪かった。さらに、比較例４、５の場合、（メタ）アクリル系共重合体組成物は得られたものの粘度が非常に高く、顔料の分散処理を行うことができなかったため、インクの貯蔵安定性と印刷物の隠ぺい性の評価を行うことができなかった。
　単量体（ａ）由来の構成単位または単量体（ｂ）由来の構成単位を有さない比較例６、７の（メタ）アクリル系共重合体は、アルカリ水への溶解性が悪かった。また、比較例６、７の場合、（メタ）アクリル系共重合体がアルカリ水に完全に溶解せず、（メタ）アクリル系共重合体組成物およびインクを調製することができなかったため、インクの貯蔵安定性と印刷物の隠ぺい性の評価を行うことができなかった。 On the other hand, as is clear from the results in Table 2, a comparison using a (meth) acrylic copolymer which does not have a chemical structure derived from a trifunctional or higher mercaptan and instead has a chemical structure derived from a monofunctional mercaptan. In the cases of Examples 1 and 2, the storage stability of the ink and the concealment of the printed matter were poor.
HDDA (1,6-hexanediol diacrylate) as a structural unit derived from the monomer (c2), although it does not have a chemical structure derived from a trifunctional or higher functional mercaptan and instead has a chemical structure derived from a monofunctional mercaptan. The (meth) acrylic copolymer of Comparative Example 3 having a constituent unit of origin had poor solubility in alkaline water. Further, in the case of Comparative Example 3, although the (meth) acrylic copolymer composition was obtained, the viscosity was very high and the pigment could not be dispersed, so that the ink storage stability and the concealment of the printed matter were concealed. The sex could not be evaluated.
It does not have a chemical structure derived from a trifunctional or higher functional mercaptan, but instead has a chemical structure derived from a monofunctional mercaptan or a chemical structure derived from a bifunctional mercaptan, but the ratio thereof is higher than that in Comparative Examples 1 and 2. The few (meth) acrylic copolymers of Comparative Examples 4 and 5 did not dissolve in the eluent, and GPC measurement could not be performed. Moreover, the solubility in alkaline water was poor. Further, in the cases of Comparative Examples 4 and 5, although the (meth) acrylic copolymer composition was obtained, the viscosity was very high and the pigment could not be dispersed, so that the ink storage stability and the printed matter were printed. Could not evaluate the concealment of.
The (meth) acrylic copolymers of Comparative Examples 6 and 7 having no structural unit derived from the monomer (a) or the structural unit derived from the monomer (b) had poor solubility in alkaline water. .. Further, in the cases of Comparative Examples 6 and 7, the (meth) acrylic copolymer was not completely dissolved in alkaline water, and the (meth) acrylic copolymer composition and the ink could not be prepared. It was not possible to evaluate the storage stability of the ink and the concealment of the printed matter.
　本発明によれば、アルカリ水への溶解性が良好であり、インクの貯蔵安定性とフィルム印刷における隠ぺい性が良好な（メタ）アクリル系共重合体、前記（メタ）アクリル系共重合体を含む（メタ）アクリル系共重合体組成物および前記（メタ）アクリル系共重合体組成物を含むインクを提供することができる。したがって、本発明の（メタ）アクリル系共重合体は、アルカリ水溶液によって現像可能な樹脂組成物の分野においても好適に利用でき、産業上極めて重要である。 According to the present invention, the (meth) acrylic copolymer and the (meth) acrylic copolymer having good solubility in alkaline water and good storage stability of ink and good concealment in film printing can be obtained. It is possible to provide an ink containing the (meth) acrylic copolymer composition containing the (meth) acrylic copolymer composition and the (meth) acrylic copolymer composition. Therefore, the (meth) acrylic copolymer of the present invention can be suitably used in the field of resin compositions that can be developed with an alkaline aqueous solution, and is extremely important in industry.

Claims (12)

  1. 　アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル由来の構成単位と、酸基含有ビニル化合物由来の構成単位と、３官能以上のメルカプタン由来の化学構造とを有し、粒子状の固体である、（メタ）アクリル系共重合体。 A particle having a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, a structural unit derived from an acid group-containing vinyl compound, and a chemical structure derived from a trifunctional or higher functional mercaptan. A (meth) acrylic copolymer that is a solid state.
  2. 　アルキル基の炭素数が１～８である（メタ）アクリル酸アルキルエステル由来の構成単位と、酸基含有ビニル化合物由来の構成単位と、３官能以上のメルカプタン由来の化学構造とを有し、単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する、（メタ）アクリル系共重合体。 It has a structural unit derived from a (meth) acrylic acid alkyl ester having 1 to 8 carbon atoms in an alkyl group, a structural unit derived from an acid group-containing vinyl compound, and a chemical structure derived from a trifunctional or higher functional mercaptan. A (meth) acrylic copolymer further having one or more chemical structures selected from the group consisting of a functional mercaptan-derived chemical structure and a bifunctional mercaptan-derived chemical structure.
  3. 　前記（メタ）アクリル系共重合体の二次ガラス転移温度が、３５℃以上である、請求項１または２に記載の（メタ）アクリル系共重合体。 The (meth) acrylic copolymer according to claim 1 or 2, wherein the secondary glass transition temperature of the (meth) acrylic copolymer is 35 ° C. or higher.
  4. 　重合性二重結合を２つ以上有する化合物由来の構成単位をさらに含む、請求項１～３のいずれか一項に記載の（メタ）アクリル系共重合体。 The (meth) acrylic copolymer according to any one of claims 1 to 3, further comprising a structural unit derived from a compound having two or more polymerizable double bonds.
  5. 　単官能のメルカプタン由来の化学構造および２官能のメルカプタン由来の化学構造からなる群から選ばれる１種以上の化学構造をさらに有する、請求項１、３、４のいずれか一項に記載の（メタ）アクリル系共重合体。 The (meth) according to any one of claims 1, 3 and 4, further comprising one or more chemical structures selected from the group consisting of monofunctional mercaptan-derived chemical structures and bifunctional mercaptan-derived chemical structures. ) Acrylic copolymer.
  6. 　前記（メタ）アクリル系共重合体の質量平均粒子径が、２０～２０００μｍである、請求項１～５のいずれか一項に記載の（メタ）アクリル系共重合体。 The (meth) acrylic copolymer according to any one of claims 1 to 5, wherein the (meth) acrylic copolymer has a mass average particle size of 20 to 2000 μm.
  7. 　前記（メタ）アクリル系共重合体の含水率が、０．０１～１０質量％である、請求項１～６のいずれか一項に記載の（メタ）アクリル系共重合体。 The (meth) acrylic copolymer according to any one of claims 1 to 6, wherein the (meth) acrylic copolymer has a water content of 0.01 to 10% by mass.
  8. 　前記（メタ）アクリル系共重合体の酸価が、２０～１４０ｍｇＫＯＨ／ｇである、請求項１～７のいずれか一項に記載の（メタ）アクリル系共重合体。 The (meth) acrylic copolymer according to any one of claims 1 to 7, wherein the acid value of the (meth) acrylic copolymer is 20 to 140 mgKOH / g.
  9. 　前記（メタ）アクリル系共重合体の重量平均分子量が、１５０００～８００００である、請求項１～８のいずれか一項に記載の（メタ）アクリル系共重合体。 The (meth) acrylic copolymer according to any one of claims 1 to 8, wherein the (meth) acrylic copolymer has a weight average molecular weight of 15,000 to 80,000.
  10. 　請求項１～９のいずれか一項に記載の（メタ）アクリル系共重合体と、水と、塩基性化合物とを含む、（メタ）アクリル系共重合体組成物。 A (meth) acrylic copolymer composition containing the (meth) acrylic copolymer according to any one of claims 1 to 9, water, and a basic compound.
  11. 　顔料をさらに含む、請求項１０に記載の（メタ）アクリル系共重合体組成物。 The (meth) acrylic copolymer composition according to claim 10, further comprising a pigment.
  12. 　請求項１０または１１に記載の（メタ）アクリル系共重合体組成物を含む、インク。 An ink containing the (meth) acrylic copolymer composition according to claim 10 or 11.
PCT/JP2021/029243 2020-11-18 2021-08-06 (meth)acrylic copolymer, (meth)acrylic copolymer composition, and ink WO2022107402A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202180067390.2A CN116390960A (en) 2020-11-18 2021-08-06 (meth) acrylic copolymer, (meth) acrylic copolymer composition and ink
JP2022563580A JPWO2022107402A1 (en) 2020-11-18 2021-08-06

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-192003 2020-11-18
JP2020192003 2020-11-18

Publications (1)

Publication Number Publication Date
WO2022107402A1 true WO2022107402A1 (en) 2022-05-27

Family

ID=81708772

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/029243 WO2022107402A1 (en) 2020-11-18 2021-08-06 (meth)acrylic copolymer, (meth)acrylic copolymer composition, and ink

Country Status (3)

Country Link
JP (1) JPWO2022107402A1 (en)
CN (1) CN116390960A (en)
WO (1) WO2022107402A1 (en)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04304277A (en) * 1990-12-27 1992-10-27 Vianova Kunstharz Ag Coating material binder that is based on acrylic ester copolymer and can be diluted with water
JP2005097406A (en) * 2003-09-24 2005-04-14 Nippon Shokubai Co Ltd Uv ray-curable hot-melt adhesive composition
US20140179823A1 (en) * 2012-12-21 2014-06-26 Rohm And Haas Company Acrylic dispersions with multi-functional acrylates for uv-cure coatings
JP2016196626A (en) * 2015-04-02 2016-11-24 アイカ工業株式会社 Reactive hot melt composition for automobile lamp tool and automobile lamp fitting
WO2019065604A1 (en) * 2017-09-29 2019-04-04 富士フイルム株式会社 Aqueous composition and macromolecular compound
JP2019163417A (en) * 2018-03-20 2019-09-26 富士フイルム株式会社 Ink, ink set, inkjet recording method, and manufacturing method of ink
JP2019207143A (en) * 2018-05-29 2019-12-05 東洋インキＳｃホールディングス株式会社 Blocking agent for biochemical analysis
EP3587459A1 (en) * 2018-06-23 2020-01-01 Helios, Tovarna Barv lakov in umetnih smol Kolicevo, d.o.o. Synthetic resin for preparation of protective coatings and process for preparation of coatings on the basis of such resin
JP2020041071A (en) * 2018-09-12 2020-03-19 住友化学株式会社 Composition, cured film and display device

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04304277A (en) * 1990-12-27 1992-10-27 Vianova Kunstharz Ag Coating material binder that is based on acrylic ester copolymer and can be diluted with water
JP2005097406A (en) * 2003-09-24 2005-04-14 Nippon Shokubai Co Ltd Uv ray-curable hot-melt adhesive composition
US20140179823A1 (en) * 2012-12-21 2014-06-26 Rohm And Haas Company Acrylic dispersions with multi-functional acrylates for uv-cure coatings
JP2016196626A (en) * 2015-04-02 2016-11-24 アイカ工業株式会社 Reactive hot melt composition for automobile lamp tool and automobile lamp fitting
WO2019065604A1 (en) * 2017-09-29 2019-04-04 富士フイルム株式会社 Aqueous composition and macromolecular compound
JP2019163417A (en) * 2018-03-20 2019-09-26 富士フイルム株式会社 Ink, ink set, inkjet recording method, and manufacturing method of ink
JP2019207143A (en) * 2018-05-29 2019-12-05 東洋インキＳｃホールディングス株式会社 Blocking agent for biochemical analysis
EP3587459A1 (en) * 2018-06-23 2020-01-01 Helios, Tovarna Barv lakov in umetnih smol Kolicevo, d.o.o. Synthetic resin for preparation of protective coatings and process for preparation of coatings on the basis of such resin
JP2020041071A (en) * 2018-09-12 2020-03-19 住友化学株式会社 Composition, cured film and display device

Also Published As

Publication number Publication date
JPWO2022107402A1 (en) 2022-05-27
CN116390960A (en) 2023-07-04

Similar Documents

Publication Publication Date Title
EP1710284B1 (en) Aqueous polymer dispersions
JP5507245B2 (en) Production of aluminum phosphate or polyphosphate aluminum particles
JP5683263B2 (en) Nonionic water-soluble additive
AU2013364228B2 (en) Grafted pigment dispersing polymeric additive and paint employing the same with improved hiding
KR101200124B1 (en) High-molecular dispersant for inorganic pigments
US9574105B2 (en) Coating composition comprising autoxidisable component
JPH01213371A (en) Aqueous coating composition having sweeping mechanism of anionic seed
EP3523381B1 (en) Latex paint containing titanium dioxide pigment
WO2022107402A1 (en) (meth)acrylic copolymer, (meth)acrylic copolymer composition, and ink
AU2017339556B2 (en) Latex paint containing titanium dioxide pigment
CN111234093A (en) Acrylic polymer particles, method for producing same, ink composition, and coating composition
WO2023276708A1 (en) Thickener and adhesive composition
US20140194585A1 (en) Bulk polymerization of (meth)acrylate copolymers soluble under aqueous-alkaline conditions
JPH0649131A (en) Production of @(3754/24)meth)acrylic polymer with high acid value
JPH0258285B2 (en)
CN107109088B (en) The additive of covering for raising and coating compositions comprising it
JPH06211942A (en) Production of vinyl polymer for pigment dispersion
EP3130617B1 (en) Polymer nanoparticle preparation by miniemulsion polymerization
WO2017022423A1 (en) (meth)acrylic crosslinked particles and method for producing same
JP5063182B2 (en) Vinyl polymer and method for producing the same
CN113661189A (en) Resin particle, method for producing same, and hydrophilicity-imparting agent containing same

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21894277

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022563580

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21894277

Country of ref document: EP

Kind code of ref document: A1