JPH04225081A - Aqueous printing ink composition - Google Patents

Abstract

PURPOSE:To obtain an aqueous printing ink composition having excellent bond strength, suitable for providing excellently printing effects, useful for compounded cartons obtained by printing paper substrates with the aqueous printing ink composition, and laminating a thermoplastic resin for extrusion lamination represented by polyethylene. CONSTITUTION:An aqueous printing ink composition comprising (A) a resin acid salt obtained by neutralizing a carboxyl group-containing acrylic resin with a basic substance, (B) water and a colorant and (C) an organic metallic chelate compound.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a water-based printing ink, and its purpose is to
An object of the present invention is to provide a water-based printing ink composition that is suitable for use in composite paper containers obtained by laminating thermoplastic resins for extrusion lamination, such as polyethylene, and that has good adhesive strength and is suitable for obtaining excellent printing effects. It is something.

0002

[Prior Art] In recent years, beverages such as milk and juice have been made using plastic films instead of the conventional glass bottles and metal cans because they are lightweight and easy to handle and have a good display effect at retail stores. Composite paper containers laminated with aluminum are widely used.

[0003] Printing on composite paper containers generally includes two methods: one is to print on a paper base material and then extrude and laminate polyethylene, etc., and the other is to extrude and laminate polyethylene, etc. onto a paper base material, and then print on the surface of the paper base material. .

[0004] In the latter method, the printing ink is required to have physical and chemical resistance such as chemical resistance and abrasion resistance, whereas in the former method, the ink is laminated and cannot be exposed to the outside air directly. There is no need for the above-mentioned resistance. However, when extrusion lamination is performed on a paper base material, the anchor coating agent is not applied, so it is desired that the printing ink maintains sufficient lamination strength.

[0005] For such purposes, oil-based inks made of resins such as nitrified cotton, alkyd, and rosin have been used.

[0006] In recent years, efforts have been made to prevent air pollution, improve working environments,
For disaster prevention reasons, shellac, rosin, maleic acid-based water-soluble resins, acrylic resins, styrene/acrylic resins,
Water-based printing inks whose compositions include various copolymer resins such as styrene/maleic resin and styrene/acrylic/maleic resin are used.

However, water-based inks suitable for this purpose are not suitable for this purpose, such as those that have printability but insufficient lamination strength, and those that have sufficient lamination strength but have poor printing effects such as gloss and leveling properties. There wasn't.

[0008]

[Problems to be Solved by the Invention] Although acrylic resin-based inks can easily provide printing effects such as gloss and leveling, the lamination strength is low and unstable. Inks made of shellac or rosin-modified maleic acid resins have high lamination strength, but lack gloss and sharpness of hue, and printing effects are insufficient.

[0009] Water-based ink made by mixing shellac, rosin-modified maleic acid resin, etc. with acrylic resin system can achieve both printing effect and lamination strength to a certain extent, but it causes increase in ink viscosity and separation due to lack of compatibility. It has little commercial value.

[0010] As a result of extensive studies, the present inventor has found that by incorporating an organometallic chelating agent into a specific resin component that has excellent printing effects and is easy to obtain lamination strength, it has been possible to achieve commercially excellent printing effects and lamination strength. However, it has been discovered that these are compatible, leading to the present invention.

[0011]

[Structure of the invention]

[Means for Solving the Problems] The present invention provides (A) a resin acid salt obtained by neutralizing a carboxyl group-containing acrylic resin with a basic substance, (B) water and a coloring agent, and (C) an organometallic chelate compound. , and the present invention also provides the above water-based printing ink, wherein the carboxyl group-containing acrylic resin is an acrylic resin having a glass transition point of 70 to 140°C.

In the present invention, the carboxyl group-containing acrylic resin includes (meth)acrylic acid, itaconic acid,
Polymerizable unsaturated carboxylic acids such as maleic acid, fumaric acid, crotonic acid or their anhydrides, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylic acid 2 -Ethylhexyl, 2-hydroxyethyl (meth)acrylate, (meth)
(meth)acrylic acid esters such as 2-hydroxypropyl acrylate, (meth)acrylic monomers other than (meth)acrylic acid such as (meth)acrylamide, acrylontolyl, and if necessary α-methylstyrene and acetic acid. It is an acrylic resin obtained by copolymerizing vinyl or the like using polymerization methods such as milk polymerization, solution polymerization, and bulk polymerization.

The glass transition point of these carboxyl group-containing acrylic resins is in the range of 70 to 140°C, preferably 8.
It is desirable that the temperature be between 0°C and 130°C.

[0014] If the glass transition point of the carboxyl group-containing acrylic resin is less than 70°C, it is difficult to obtain sufficient lamination strength, and if it exceeds 140°C, the dried coating film becomes brittle and the printed matter is easily scratched, resulting in a poor printing effect. cannot be obtained.

[0015] The weight average molecular point of these carboxyl group-containing acrylic resins is preferably 7,000 or more.

[0016] The above carboxyl group-containing acrylic resin is
Neutralize with organic amines such as trimethylamine, triethylamine, dimethylaminoethanol, monoethanolamine, triethanolamine, morpholine, etc. or ammonia, preferably ammonia, to a pH of about 6 to 9 (
A) It is a resin acid salt.

In the present invention, examples of the organometallic chelate compound include di-iso-propoxybis(acetylacetone) titanate, di-n-butoxybis(triethanolamine)titanate (TAT), and di-hydroxybis(lactic acid)titanate. (TLA), tetra-octylene glycol titanate, di-iso-propoxy bis(ethyl acetoacetate) titanate, poly-(hydroxytitanium stearate), di-iso-propoxyaluminum monoethyl acetoacetate, di-iso-
propoxyaluminum monomethyl acetoacetate,
Di-n-butoxyaluminum-mono-ethylacetoacetate, aluminum tris(ethylacetoacetate), aluminum monoacetylacetonate bis(ethylacetoacetate) (ALD), aluminum tris(acetylacetoacetonate) (ALA), aluminum- Di-n-butoxide mono-methyl acetoacetate, aluminum diisobutoxide mono-
Methyl acetoacetate, aluminum-di-sec-
Butoxide-mono-ethylacetoacetate trilactate ammonium zirconate, triglycolate ammonium zirconate, and the like can be mentioned.

The amount of the organometallic chelate compound used is 0.
It is 1 to 10% by weight. In the case of 0.1 or less,
If the lamination strength is insufficient and the amount exceeds 10% by weight, it is not only uneconomical but also increases the viscosity of the ink over time and causes plate clogging due to decreased resolubility, resulting in a loss of printing effectiveness.

For example, the amount of the organometallic chelate compound to be used for an acrylic resin having a glass transition point of 100° C. to 120° C. is preferably 2 to 7% by weight based on 100 g of ink.

The aqueous printing ink according to the present invention can be obtained by adding colorants such as pigments, fillers, and other necessary additives, and by a known kneading method.

[0021] The water-based printing ink of the present invention may also contain shellac resin, rosin-modified maleic acid resin, carboxylated petroleum resin, cellulose resin, and styrene maleic acid resin, if necessary, within a range that does not impede its performance. Can be used together.

[0022]

[Action] The water-based printing ink compositions made of these compositions have the effect of increasing the cohesive force of the coating film and the affinity for dissolved polyethylene, which are necessary to obtain laminate strength, and thereby obtain stable laminate strength. it is conceivable that.

[0023]

[Examples] The present invention will be explained below with reference to Examples. In the examples, "part" means part by weight, and "%" means % by weight.

Production Examples 1 to 5 Isopropyl alcohol 30
0 part was heated to 83°C, and while refluxing it, 200 parts of a monomer mixture having the composition shown in Table 1 and 6 parts of azobisisobutyronitrile were added dropwise over 2 hours, and then heated to 83°C for 4 hours. Made it react. Next, the entire amount of isopropyl alcohol was distilled off under reduced pressure, and 600 parts of water containing ammonia equivalent to the carboxyl group in the reaction product was added to form an aqueous solution of acrylic resin (solid content 25%) (a) shown in Table 1. ~(e) was obtained. In addition, the glass transition temperature of the resin shown in Table 1 is:
From the glass transition point temperature (Tgi) of the homopolymer of each monomer and the weight fraction (Wi) of each monomer, Gord of the following formula
It was calculated using the on-Taylor law. 1/Tg=Σ(Wi/Tgi)

Production Examples 6 to 8 Acrylic resin aqueous solution (c) obtained in Production Example 3 400
and 126 parts of water were kept at 80°C, and 200 parts of a monomer mixture having the composition shown in Table 2 and 24 parts of an aqueous solution of 4 parts of ammonium persulfate dissolved in 20 parts of water were added dropwise over 1 hour.
The reaction was carried out until the solid content reached 40% to obtain hydrosol type acrylic resin emulsions (f) to (h).

Examples 1 to 9 and Comparative Examples 1 to 7 Production Example 1
Acrylic resin aqueous solution obtained in ~5 and 6~8 (a
) to (e) and hydrosol-type acrylic resin emulsions (f) to (h) were kneaded with 100 parts of a mixture having the composition shown in Table 3 as an example and Table 4 as a comparative example, and a water-based printing ink was prepared. was prepared. Each water-based ink was mixed with Zahn Cup No. The viscosity was measured in step 4 and defined as the finished viscosity. The obtained ink was stored in a constant temperature bath at 40° C. for one week, and storage viscosity stability was evaluated. Storage viscosity stability
○ if the viscosity is 1 to 1.5 times higher than the finished viscosity
1.5 to 2.0 times is represented by △, and 2 times or more is represented by ×.

The obtained water-based printing inks were each diluted with water, and the viscosity was adjusted to Zahn cup No. 3 for 17 seconds (25℃
), and use a gravure printing machine (plate: Helio).
175 lines/inch) on paper, and the gloss and swimming were visually judged. Those with a uniform coating film were evaluated as ○, those with some swimming were evaluated as △, and those with noticeable swimming were evaluated as ×.

[0028] Further, the obtained printed matter was laminated with molten polyethylene using an extrusion laminator,
The laminate strength was evaluated using a tensile tester. Compared to the laminate strength of the non-printed material, 1 to 2.0 times the lamination strength is represented by ◯, 1 to 0.5 times is represented by △, and 0.5 times or less is represented by ×.

[0029] In Tables 3 and 4, “Lionor Blue FG-73
30" is a phthalocyanine blue pigment (Toyo Ink Manufacturing (
"PNP-40M" is a shellac resin (manufactured by Gifu Shellac Manufacturing Co., Ltd., product name, solid content 40%), and Marquid 32-30WS is a maleic acid resin aqueous solution (Arakawa Chemical Co., Ltd.). ), product name, solid content 30
%).

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide an aqueous ink composition having sufficient printability, excellent printing effect in lamination strength, gloss, and leveling.

Claims (3)

[Claims] 1. An aqueous printing ink composition comprising (A) a resin acid salt obtained by neutralizing a carboxyl group-containing acrylic resin with a basic substance, (B) water and a colorant, and (C) an organometallic chelate compound. . 2. The aqueous printing ink composition according to claim 1, wherein the carboxyl group-containing acrylic resin is an acrylic resin having a glass transition point of 70°C to 140°C. 3. The aqueous printing ink composition according to claim 1, wherein the amount of the organometallic chelate compound added is 0.1% to 10% by weight.