JP2019052230A - Resin fluid dispersion for water-based ink and method for producing the same - Google Patents

Abstract

To provide a resin fluid dispersion for water-based ink which is suitable for obtaining water-based ink excellent in water resistance and adhesion when being printed on a soft packaging base material such as a plastic film.SOLUTION: The resin fluid dispersion for water-based ink is provided that contains: an alkali soluble type copolymer (A) of a monomer mixture including water, (meth)acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer; a copolymer (B) of a monomer mixture including diacetone acrylamide and an ethylenic unsaturated monomer; and a hydrazide compound (C), and satisfies specific conditions.SELECTED DRAWING: None

Description

  The present invention relates to a resin dispersion for water-based inks, and more particularly to a resin dispersion for water-based inks suitable for water-based inks used for printing on soft packaging substrates, and a method for producing the same.

  Gravure printing and flexographic printing are used to give cosmetics and functionality to flexible packaging materials used for food and daily necessities such as plastic films. Conventionally, ink for soft packaging materials has been a solvent type, but recently, from the viewpoint of environmental problems and resource saving, there is a strong demand for an aqueous type in which organic solvents are reduced as much as possible. In particular, flexographic inks for soft packaging materials are often used for food packaging applications, and the toxicity of solvents is a major problem, and the use of water-based materials is advancing.

  However, since the water-based ink is inferior in wettability to the plastic film as compared with the oil-based ink, the ink is repelled and a good printed matter cannot be obtained, and there is a problem that the adhesion of the ink to the film is not sufficient. Further, in order to improve pigment dispersibility and re-dissolvability, a water-soluble acrylic resin is used as a binder, but there is a problem that water resistance is lowered.

  In order to solve the above-described problems, Patent Document 1 studies an aqueous ink containing an acrylic resin obtained by copolymerization with a monomer having both an amide group and a vinyl group.

  In Patent Document 2, a resin fine particle dispersion into which a keto group or an aldehyde group is introduced is studied.

  However, even in the water-based inks obtained by these studies, the water resistance and adhesion to the substrate are still insufficient, or the adhesion and water resistance are improved, but newly on the substrate. There were other problems such as poor ink drying.

JP2009-280659A JP-A-8-1173749

  The present invention provides a resin dispersion for water-based ink having characteristics excellent in water resistance and adhesion, and a method for producing the resin dispersion for water-based ink, particularly when printed on a flexible packaging substrate. Objective.

  As a result of diligent studies to solve the above problems, the inventors of the present invention made an alkali-soluble copolymer as a shell and a core-shell emulsion having a diacetone acrylamide-containing ethylenically unsaturated monomer copolymer as a core. By using a water-based resin aqueous dispersion obtained by adding a hydrazide compound as a binder for water-based inks, it has been found that water resistance and adhesion are particularly excellent when used as a soft packaging material ink, and the present invention has been completed. .

That is, the present invention
(1) Alkali-soluble copolymer (A) of monomer mixture containing water, (meth) acrylic acid and alicyclic alkyl group-containing ethylenically unsaturated monomer, diacetone acrylamide and ethylenically unsaturated monomer A resin dispersion for water-based inks, which contains a copolymer (B) of a monomer mixture containing a polymer and a hydrazide compound (C), and satisfies the following conditions <i> to <iii>:
<I> The alkali-soluble copolymer (A) has an acid value of 50 to 150 mgKOH / g.
<Ii> The content ratio of diacetone acrylamide in the copolymer (B) is 2 to 12% by mass with respect to the total of the (A) and (B).
<Iii> The mass ratio of the alkali-soluble copolymer (A) to the copolymer (B) is (A) :( B) = 20: 80 to 60:40.
(2) The resin for water-based ink according to (1), wherein the alkali-soluble copolymer (A) has a weight average molecular weight in terms of polystyrene in gel permeation chromatography (GPC): 6,000 to 20,000. Dispersion,
(3) The aqueous solution according to (1), containing the hydrazide compound (C) at a ratio of 0.8 to 1.2 molar equivalents relative to 1 molar equivalent of keto groups contained in the resin dispersion for aqueous ink. Resin dispersion for ink,
(4) A water-based ink comprising the resin dispersion for water-based ink according to any one of (1) to (3) above,
(5) The water-based ink according to (4), which is a water-based ink for soft packaging,
(6) Ethylenic acid containing diacetone acrylamide in the presence of an alkali-soluble copolymer (A) of a monomer mixture containing (meth) acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer A mixture (b) of unsaturated monomers is emulsion-polymerized to obtain a copolymer (B), which is obtained by adding a hydrazide compound (C), and satisfies the following conditions <i> to <iii> A method for producing a resin dispersion for water-based inks, characterized in that
<I> The alkali-soluble copolymer (A) has an acid value of 50 to 150 mgKOH / g.
<Ii> The content ratio derived from diacetone acrylamide in the copolymer (B) is 2 to 12% by mass with respect to the total of the (A) and (B).
<Iii> The mass ratio of the alkali-soluble copolymer (A) to the copolymer (B) is (A) :( B) = 20: 80 to 60:40.
It is.

  By using the resin dispersion for water-based ink of the present invention as a binder for water-based ink, it is possible to obtain an ink having excellent water resistance and adhesion when printed on a flexible packaging substrate such as a plastic film.

  Below, the resin dispersion for water-based inks of this invention and its manufacturing method are demonstrated concretely.

The present invention relates to an alkali-soluble copolymer (A) of a monomer mixture containing water, (meth) acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer, diacetone acrylamide and ethylenically unsaturated monomer. It is the resin dispersion for water-based inks which contains the copolymer (B) of the monomer mixture containing a monomer, and the hydrazide compound (C).

  An alkali-soluble copolymer (A) of a monomer mixture containing (meth) acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer is (meth) acrylic acid and at least one alicyclic ring A copolymer of a monomer mixture having an ethylenically unsaturated monomer having an alkyl group as an essential component, and a base of 90 to 100% equivalent to the acid group of the alkali-soluble copolymer (A) A polymer soluble in water that has been completely or partially neutralized by adding a chemical compound and dissolving it at 80 to 90 ° C. for 3 hours. The pH of the solution obtained by solubilizing the alkali-soluble copolymer (A) in water with a base compound is preferably 7.5 to 9.0.

  When copolymerizing the alkali-soluble copolymer (A), at least one monomer selected from acrylic acid and methacrylic acid can be suitably used as (meth) acrylic acid. (Meth) acrylic acid is 6 to 23% by mass in the monomer mixture used for copolymerization of the alkali-soluble copolymer (A) so that it is soluble in water when it is a neutralized product with a basic compound. It is preferably included.

  Examples of the alicyclic alkyl group-containing ethylenically unsaturated monomer include (meth) acrylic acid esters such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and cyclooctyl (meth) acrylate. From these, one type or two or more types can be selected. The alicyclic alkyl group-containing ethylenically unsaturated monomer is contained in the monomer mixture used for copolymerization of the alkali-soluble copolymer (A) from the viewpoints of adhesion to a flexible packaging substrate and water resistance. It is preferable that 10-30 mass% is contained, and it is more preferable that 20-30 mass% is contained.

  Other monomer components that can be used for copolymerization of the alkali-soluble copolymer (A) include styrenes such as styrene and α-methylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, Examples include (meth) acrylic acid esters such as butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and benzyl (meth) acrylate, and one or more of them can be selected. Among these, (meth) acrylic acid esters are preferable from the viewpoint of adhesion to the flexible packaging substrate. The skeleton derived from these monomers is preferably contained in the monomer mixture for copolymerization of the alkali-soluble copolymer (A) in an amount of 47 to 84% by mass, and contained in an amount of 47 to 74% by mass. It is more preferable.

  That is, the ratio of each monomer when copolymerizing the alkali-soluble copolymer (A) is (meth) acrylic acid: alicyclic alkyl group-containing ethylenically unsaturated monomer: other monomer in mass ratio. = 6 to 23: 10 to 30: 47 to 84 (%), (meth) acrylic acid: alicyclic alkyl group-containing ethylenically unsaturated monomer: other monomer = 6 to 23: 20 It is more preferable that it is 30: 47-74 (%).

  In addition, in the copolymerization of the alkali-soluble copolymer (A), instead of a part of the other monomer components, any hydroxyethyl (meth) acrylate may be used as long as the effect of the present invention is not hindered. Hydroxyl group-containing ethylenically unsaturated monomers such as monoalkoxyalkylene glycol (meth) acrylates such as 2-methoxyethyl (meth) acrylate; (meth) acrylamide; N, N-dimethyl (meth) acrylamide, diacetone acrylamide N-substituted (meth) acrylamides such as dicarboxylic acid monomers such as itaconic acid and maleic acid, and anhydrides or derivatives thereof may be used alone or in combination. In general, the upper limit of 10% by mass of the monomer mixture used for copolymerization of the alkali-soluble copolymer (A) can be used.

  In the present invention, the copolymer (B) can be obtained by copolymerizing a monomer mixture containing diacetone acrylamide and an ethylenically unsaturated monomer.

  As the ethylenically unsaturated monomer component used for copolymerization of the copolymer (B), those having no ionicity are preferable, for example, styrenes such as styrene and α-methylstyrene; methyl (meth) acrylate, (Meth) acrylic acid esters such as ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, and the like. 1 type or 2 types or more can be selected. Among these, (meth) acrylic acid esters are preferable from the viewpoint of adhesion to a soft packaging substrate, and in particular, monomers that increase the glass transition temperature such as methyl methacrylate, and butyl acrylate and 2-ethylhexyl acrylate. A combination of monomers that lowers the glass transition temperature is more preferable from the viewpoint of the coating film physical properties of the ink.

  The amount of the ethylenically unsaturated monomer used for copolymerization of the copolymer (B) may be adjusted so as to satisfy the conditions <ii> and <iii> described later.

  The hydrazide compound (C) is a hydrazide compound containing two or more hydrazide groups in the molecule, and crosslinks with the keto group derived from the diacetone (meth) acrylamide skeleton in the copolymer (B). If it is. In addition to aliphatic dihydrazides such as adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, carbonic acid polyhydrazide, aliphatic, alicyclic, aromatic bissemicarbazide, aromatic dicarboxylic And acid dihydrazide, polyhydrazide of polyacrylic acid, dihydrazide of aromatic hydrocarbon, hydrazine-pyridine derivative and dihydrazide of unsaturated dicarboxylic acid such as maleic acid dihydrazide. Adipic acid dihydrazide is preferable.

The resin dispersion for water-based inks of the present invention needs to satisfy the following conditions <i> to <iii>.
<I> The alkali-soluble copolymer (A) has an acid value of 50 to 150 mgKOH / g.
<Ii> The content ratio derived from diacetone acrylamide in the copolymer (B) is 2 to 12% by mass with respect to the total of the (A) and (B).
<Iii> The mass ratio of the alkali-soluble copolymer (A) to the copolymer (B) is (A) :( B) = 20: 80 to 60:40.

Condition <i>
The alkali-soluble copolymer (A) of the (meth) acrylic acid-containing ethylenically unsaturated monomer needs to have an acid value of 50 to 150 mgKOH / g. When the acid value is less than 50 mgKOH / g, the storage stability of the emulsion is lowered, and when it exceeds 150 mgKOH / g, the water resistance of the coating film is lowered. The acid value is more preferably 70 to 150 mgKOH / g.

Condition <ii>
The content ratio of the skeleton derived from diacetone acrylamide in the copolymer (B) of the monomer mixture containing diacetone acrylamide and the ethylenically unsaturated monomer is at least the copolymer (A) from the viewpoint of coating film properties and printability. ) And (B) should be 2 to 12% by mass. If the amount is less than 2% by mass, the effect of crosslinking cannot be confirmed in the physical properties of the coating film. If the amount exceeds 12% by mass, the re-dissolution property and the plate cleaning property of the coating film are adversely affected. It is more preferable in it being 3-10 mass%. Moreover, also as a content rate of the skeleton derived from diacetone acrylamide contained in both the said copolymers (A) and (B), it is 2-12 mass% with respect to the sum total of the said copolymers (A) and (B). It is preferable that it is 3 to 10% by mass.

Condition <iii>
The mass ratio of the alkali-soluble copolymer (A) and the copolymer (B) needs to be (A) :( B) = 20: 80 to 60:40. When the mass ratio of (A) is less than 20, the polymerization of the emulsion is not sufficiently performed, or the stability of the emulsion is lowered, and when it exceeds 60, the water resistance of the ink and the adhesion to the substrate are inferior. Become. (A) :( B) = 30: 70 to 60:40 is more preferable.

  The weight average molecular weight in terms of polystyrene in the gel permeation chromatography (GPC) of the alkali-soluble copolymer (A) is 6,000 to 20,000 for the water resistance of the coating film and the storage stability of the emulsion. From the viewpoint, it is preferably 8,000 to 20,000.

  The glass transition temperature (Tg) of the entire resin component [copolymer (A) + copolymer (B)] of the resin dispersion for water-based ink of the present invention may be −5 to 30 ° C. From the viewpoints of the film forming property, water resistance, adhesion, and blocking resistance of the coating film.

  Further, the hydrazide compound (C) is 0.8 to 1 with respect to 1 molar equivalent of a keto group derived from diacetone (meth) acrylamide in the copolymer (B) in obtaining desired coating film properties. It is preferable to mix | blend in the ratio which becomes 2 molar equivalent.

  The aqueous ink resin dispersion of the present invention is a core-shell type emulsion having a copolymer (A) component as a shell part and a copolymer (B) component as a core part. This is preferable because the storage stability increases. Hereinafter, a method for producing a core-shell emulsion suitable as the resin dispersion for water-based ink of the present invention will be described.

  In the presence of the alkali-soluble copolymer (A) of a monomer mixture containing (meth) acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer, the resin dispersion for water-based ink of the present invention, It is obtained by emulsion polymerization of a monomer mixture containing diacetone acrylamide and an ethylenically unsaturated monomer to obtain a copolymer (B), and then adding a hydrazide compound (C).

  When the monomer mixture containing diacetone acrylamide and the ethylenically unsaturated monomer is emulsion-polymerized, the alkali-soluble copolymer (A) is neutralized with a basic compound and used as an aqueous solution. Examples of basic substances for neutralization include ammonia; alkylamines such as trimethylamine, triethylamine, and butylamine; alcohol amines such as dimethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol; neutralization with a base such as morpholine. can do. At this time, the pH after neutralization is not necessarily about 7. That is, the degree of neutralization is not particularly limited, and the alkali-soluble copolymer (A) may function as a polymer emulsifier when forming a core-shell emulsion.

  Using the alkali-soluble copolymer (A) as a polymer emulsifier, a monomer mixture containing diacetone acrylamide and an ethylenically unsaturated monomer is emulsion-polymerized, so that the alkali-soluble copolymer (A) is used as a shell. A core-shell type emulsion having the copolymer (B) as a core can be obtained.

  The hydrazide compound (E) is added to the core-shell type emulsion thus obtained to prepare the resin dispersion for aqueous ink of the present invention.

  A water-based ink is prepared by adding a pigment, a solvent, and other additives to the resin dispersion for water-based ink of the present invention. The water-based ink is composed of the following mass proportions. Water-based ink dispersant: pigment: solvent: other additives = 50-60: 16-20: 10-29: 5-10.

  Examples of the pigment that can be used in the present invention include organic and inorganic pigments used in general inks, paints, and recording agents.

  Organic pigments such as azo, naphtholazo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, diketopyrrolopyrrole, etc. Pigments.

  Examples of inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, bengara, kaolin clay, talc, and mica.

The pigment is preferably contained in an amount sufficient to ensure the concentration and coloring power of the ink, that is, in a proportion of 1 to 50% by weight based on the total weight of the ink. In addition, pigments can be used alone or in combination of two or more. In the water-based ink of the present invention, water and a water-soluble organic solvent may be used in a small amount. Examples of such solvents include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and n-propyl alcohol, glycols such as ethylene glycol and propylene glycol, butyl cellosolve, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. And glycol ethers such as diethylene glycol monobutyl ether. Here, the small amount means a minimum amount in consideration of the discharge amount to the environment and the drying property at the time of printing.

  Additives that can be blended include, but are not limited to, pigment dispersants, leveling agents, viscosity modifiers, preservatives, antifoaming agents, and rust inhibitors.

  In particular, the water-based ink of the present invention can provide a printed material having excellent water resistance and ink adhesion when a soft package is used as a base material. Examples of the soft packaging as the printing substrate include various plastic films such as polyolefin, modified polyolefin, polyester, nylon, and polystyrene. In particular, a film subjected to corona discharge treatment has excellent adhesion to ink since it has a carbonyl group on the film surface.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the examples, “parts” and “%” are based on mass unless otherwise specified.

<Examples of production of alkali-soluble copolymer (A) A-1 to A-14>
100 parts of propylene glycol monomethyl ether acetate (PGMAc) as a solvent was charged into a four-necked separaflas equipped with a stirrer, thermometer, cooler, and nitrogen inlet tube, and after setting to a nitrogen atmosphere, the internal temperature was set to 145 ° C. did. Next, while introducing nitrogen gas, 100 parts of the monomer mixture shown in Tables 1 and 2 and 4 parts of di-t-butyl peroxide (DTBP) as a polymerization initiator were added for 3 hours using a metering pump. It was dripped over. After completion of the dropwise addition, the copolymerization reaction was advanced by keeping the temperature at the same temperature for 2 hours. The obtained copolymer liquid was heated to 180 ° C. and subjected to atmospheric distillation. When the fraction flowing out decreased, PGMAc was distilled off by vacuum distillation to obtain alkali-soluble copolymers A-1 to A-14 shown in Tables 1 and 2.

(Explanation of abbreviations in Tables 1 and 2)
AA: acrylic acid MAA: methacrylic acid DAAM: diacetone acrylamide MMA: methyl methacrylate BA: butyl acrylate
2EHA: 2-ethylhexyl acrylate CHA: cyclohexyl acrylate CHMA: cyclohexyl methacrylate

<Production Examples of Resin Dispersion for Aqueous Inks Examples 1-14, Comparative Examples 1-8>
A four-necked separaflas equipped with a stirrer, thermometer, cooler, and nitrogen inlet tube, the types and amounts of alkali-soluble copolymers (A) shown in Tables 3 to 6, and a base for neutralization The aqueous solution was charged with an equivalent amount to the acid value of the copolymer (A) using 25% aqueous ammonia as a functional compound, heated to 80 ° C., kept warm for 3 hours and dissolved to obtain an aqueous solution. Thereafter, the glass transition temperature of the entire resin component [copolymer (A) + copolymer (B)] of the resin dispersion for water-based ink is 19 to 26 ° C. while introducing nitrogen gas while maintaining 80 ° C. Monomers and amounts shown in Tables 3 to 6 and 0.5 part of 10% ammonium persulfate aqueous solution were added dropwise with a metering pump over 3 hours so as to be within the range. After the remaining monomer was polymerized by maintaining the temperature at 80 ° C. for 2 hours after the completion of the dropping, the amount of adipic acid dihydrazide shown in Tables 3 to 6 was added and stirred at 60 to 70 ° C. for 30 minutes. Dissolved. Then, moderate water was added and cooled so that the viscosity of the resin dispersion for water-based inks at 25 ° C. was about 1000 mPa · s, and Examples 1 to 12 described in Tables 3 and 4 and Tables 5 and 5 were used. The resin dispersion for water-based inks of Comparative Examples 1 to 8 described in 6 was obtained. In addition, the non volatile matter in a table | surface represents the ratio (%) of the non volatile matter with respect to the resin dispersion liquid for aqueous inks, when drying the resin dispersion liquid for water based inks at 180 degreeC for 1 hour with a dryer.

<Emulsion stability>
Stability was evaluated by visually observing the viscosity change and appearance of the emulsion after the aqueous ink dispersion was stored at 40 ° C. for 1 month.
○: Viscosity change is 30% or less, and no aggregates are formed.
(Triangle | delta): 30%-60% of viscosity changes, or a part aggregate occurs.
X: Viscosity change 60% or more, or an agglomerate occurs.

(* 1) At the end of the reaction, there was much resin adhesion to the flask and it was unstable as an emulsion.

(Explanation of abbreviations in Table 3 to Table 6)
MMA: methyl methacrylate 2EHA: 2-ethylhexyl acrylate DAAM: diacetone acrylamide ADH: adipic acid dihydrazide

<Preparation of aqueous pigment dispersion>
As pigment, 50 parts of titanium oxide CR-90 (manufactured by Ishihara Sangyo Co., Ltd.), 8 parts of ML-2146 (manufactured by Seiko PMC Co., Ltd.) as pigment dispersing resin, 42 parts of ion-exchanged water, and 150 parts of glass beads After charging in a 250 ml plastic bottle and shaking for 30 minutes with a paint shaker, the glass beads were removed to obtain an aqueous pigment dispersion.

<Preparation of water-based ink>
50 parts of the obtained aqueous pigment dispersion and 50 parts of a resin dispersion for aqueous ink were mixed to obtain an aqueous ink. The film properties of the obtained ink were evaluated by the following methods.

<Water resistance>
A water-based ink prepared on a corona-treated OPP film was coated with a bar coater # 10. After drying at room temperature for one day, the surface state after rubbing the coating film portion with gauze soaked with ion-exchanged water 10 times was visually evaluated. Tables 7 to 10 show the results of evaluation based on the following criteria.
A: No trace.
○: There is a slight trace.
Δ: Part of the coating film peels off.
X: The coating film peels off and the substrate is visible.

<Adhesion>
A water-based ink prepared on a corona-treated OPP film was coated with a bar coater # 10. After drying at room temperature for one day, a cellophane tape having a width of 18 mm (manufactured by Nichiban Co., Ltd.) was adhered to the coating film portion, and then the tape was removed, and the state of the peeled portion was visually evaluated. Tables 7 to 10 show the results of evaluation based on the following criteria.
A: No trace.
○: There is a slight trace.
Δ: Part of the coating film peels off.
X: The coating film peels off and the substrate is visible.

  The water-based ink of Example 15 using the resin dispersion for water-based ink of the present invention obtained in Example 1 contains an alicyclic alkyl group in the monomer-derived skeleton constituting the alkali-soluble copolymer (A). It is an example containing cyclohexyl acrylate which is an ethylenically unsaturated monomer. This water-based ink is Comparative Example 1 and Comparative Example in which an alkali-soluble copolymer (A) that does not contain a skeleton derived from an alicyclic alkyl group-containing ethylenically unsaturated monomer and is outside the scope of the present invention is used. Compared with Comparative Example 9 and Comparative Example 10 using the aqueous ink resin dispersion obtained in No. 2, it is understood that the water resistance and adhesion are excellent.

  In the aqueous inks of Examples 15, 24, and 25 using the resin dispersion for aqueous ink of the present invention obtained in Examples 1, 10, and 11, the acid value of the alkali-soluble copolymer (A) is In this example, 104 mgKOH / g, 60 mgKOH / g, and 140 mgKOH / g are used. In addition, the aqueous ink of Example 19 using the resin dispersion for aqueous ink obtained in Example 5 in which the acid value is 104 mgKOH / g within the range of the present invention has an acid value outside the range of the present invention. Compared with the water-based inks of Comparative Examples 15 and 16 using the resin dispersions for water-based inks obtained in Comparative Examples 7 and 8 with 40 mgKOH / g and 180 mgKOH / g, the water resistance and adhesion are excellent. I understand.

  The aqueous inks of Examples 15, 19, 20, and 21 using the resin dispersion for aqueous ink of the present invention obtained in Examples 1, 5, 6, and 7 are derived from diacetone acrylamide in the copolymer (B). It is an example using the copolymer (B) whose content rate is in the range of 2 to 12% by mass with respect to the total of the copolymer (A) and the copolymer (B). Compared with the water-based ink of Comparative Example 11 using the resin dispersion for water-based ink obtained in Comparative Example 5 having a glass transition temperature similar to that of Examples 1 and 5 and diacetone acrylamide being outside the above range. It turns out that it is excellent in water resistance and adhesiveness. Further, even when compared with the aqueous ink of Comparative Example 13 using the resin dispersion for aqueous ink of Comparative Example 5 having a skeleton derived from diacetone acrylamide only in the copolymer (A), water resistance and adhesion It turns out that it is excellent in property.

  The aqueous inks of Examples 15, 22, and 23 using the aqueous ink resin dispersions of the present invention obtained in Examples 1, 8, and 9 are respectively alkali-soluble copolymers in the aqueous ink resin dispersions. In this example, the mass ratio of (A) to the copolymer (B) is 40:60, 20:80, and 60:40, respectively. These water-based inks are more resistant to water than the water-based ink of Comparative Example 11 using the resin dispersion for water-based ink obtained in Comparative Example 3 in which the mass ratio is 67:33 which is outside the scope of the present invention. And it turns out that it is excellent in adhesiveness. Moreover, it is excellent in emulsion stability compared with the comparative example 4 which made the said mass ratio 15:85 which is outside the range of this invention, and the comparative example 9 using the resin dispersion for water-based inks obtained in the comparative example 12 It turns out that it is excellent in water resistance and adhesiveness compared with water-based ink.

  The water-based inks of Examples 15, 26, 27, and 28 using the resin dispersions for water-based inks of the present invention obtained in Examples 1, 12, 13, and 14 are weight averages of the alkali-soluble polymer (A). In this example, molecular weights of 12,000, 7,000, 9,000, and 18,000 are used, but it is understood that the water resistance and adhesion are excellent.

Claims (6)

Including an alkali-soluble copolymer (A) of a monomer mixture containing water, (meth) acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer, including diacetone acrylamide and an ethylenically unsaturated monomer A resin dispersion for water-based inks comprising a monomer mixture copolymer (B) and a hydrazide compound (C) and satisfying the following conditions <i> to <iii>.
<I> The alkali-soluble copolymer (A) has an acid value of 50 to 150 mgKOH / g.
<Ii> The content ratio derived from diacetone acrylamide in the copolymer (B) is 2 to 12% by mass with respect to the total of the (A) and (B).
<Iii> The mass ratio of the alkali-soluble copolymer (A) to the copolymer (B) is (A) :( B) = 20: 80 to 60:40. The resin dispersion for water-based ink according to claim 1, which has a polystyrene-reduced weight average molecular weight of 6,000 to 20,000 in gel permeation chromatography (GPC) of the alkali-soluble copolymer (A). The hydrazide compound (C) is contained at a ratio of 0.8 to 1.2 molar equivalents relative to 1 molar equivalent of keto groups contained in the resin dispersion for water-based inks. Resin dispersion for water-based inks. A water-based ink comprising the resin dispersion for water-based ink according to any one of claims 1 to 3. The water-based ink according to claim 4, which is a water-based ink for soft packaging. Diacetone acrylamide and ethylenically unsaturated monomer in the presence of an alkali-soluble copolymer (A) of a monomer mixture containing (meth) acrylic acid and an alicyclic alkyl group-containing ethylenically unsaturated monomer A copolymer mixture (B) is obtained by emulsion polymerization of a monomer mixture containing hydrazide compound (C), and the following conditions <i> to <iii> are satisfied: A method for producing a resin dispersion for water-based inks.
<I> The alkali-soluble copolymer (A) has an acid value of 50 to 150 mgKOH / g.
<Ii> The content ratio derived from diacetone acrylamide in the copolymer (B) is 2 to 12% by mass with respect to the total of the (A) and (B).
<Iii> The mass ratio of the alkali-soluble copolymer (A) to the copolymer (B) is (A) :( B) = 20: 80 to 60:40.