JPH04209672A - Gravure ink composition - Google Patents

Abstract

PURPOSE:To improve the adhesion and adaptability to printing on an aluminum foil having a lowered wet tensile strength by mixing a vinyl chloride/vinyl carboxylate copolymer resin which contains a specified copolymer resin with a pigment and an organic solvent. CONSTITUTION:A vinyl chloride/vinyl carboxylate copolymer resin is obtained by copolymerizing vinyl chloride (i), a vinyl ester of a carboxylic acid (ii), and another copolymerizable compound (iii) preferably containing a hydroxylated compound. By copolymerizing 50 to 95wt.% component (i), 5 to 50wt.% component (ii), and 0.01 to 5wt.% phosphoric ester (iv) containing a C=C bond copolymerizable with components (i) to (iii), a copolymer resin (b) containing component (iv) is obtained. By mixing the component (a) with 10 to 90wt.% component (b), a mixture is obtained. The title composition is obtained by mixing the above mixture, 5 to 50wt.% pigment, 40 to 85wt.% organic solvent and, optionally, an additive.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a gravure ink composition that is printed on aluminum foil or aluminum X-coated film.

<Prior art and problems> In printing various packaging materials, various films are used as base materials, but in order to obtain high-quality printed matter with a bright metallic luster, especially in flexible packaging printing, it is necessary to
The base material is aluminum foil or aluminum vapor-deposited film, and organic solvent-based gravure ink is printed using a gravure printing method with high printing accuracy.

In addition, in order to further increase the added value of printed materials, post-processing such as laminating or removing aluminum with acid or alkali and then laminating is performed to add beauty to printed materials and protect the printing surface. It gives the function of

Conventionally, polyamide resins, vinyl chloride/vinyl acetate/maleic acid copolymer resins, and the like have been widely used as binder resins for inks printed on the aluminum surface.

On the other hand, the aluminum surface that serves as the base material is easily oxidized in the air, and the wet tension of the aluminum surface often decreases significantly due to oxidation. It is necessary to have sufficient adhesion even to contaminated aluminum foil or aluminum vapor-deposited film (contaminated aluminum foil or contaminated aluminum vapor-deposited film).

However, when the former resin is used, although it has a certain degree of adhesion to glossy, non-contaminated aluminum surfaces, it does not have sufficient adhesion to contaminated aluminum surfaces, and it does not adhere well after laminating. It also has no processing suitability. Furthermore, there were other problems such as generation of a rancid odor from the polyamide.

On the other hand, if the latter resin is used, it is possible to produce ink with excellent lamination suitability and water resistance.
Like the former, it does not have sufficient adhesion to contaminated aluminum surfaces.

Therefore, when both resins are used as binder resins, it is extremely difficult to obtain a gravure ink with excellent adhesiveness and suitability for post-processing.

For example, in JP-A-63-112675 or JP-A-2-9114.1 in the field of adhesives, a phosphate ester having a copolymerizable carbon-carbon double bond is added to vinyl chloride and carboxylic acid vinyl ester. It is disclosed that an adhesive made of a copolymer resin obtained by copolymerizing the above has good adhesion to metal surfaces.

However, the copolymer resins in the above-mentioned prior documents are
Although it can be applied as an adhesive, it has poor pigment dispersibility and is not suitable for use as a binder resin for printing inks. In the field of printing inks, the basic performance of inks is largely controlled by the degree of dispersion of pigments, and if a resin with poor pigment dispersibility is used as a binder, it is difficult to obtain printing inks with good printability and suitability for post-processing. This is the result.

The present invention aims to solve the above-mentioned problems in gravure inks using vinyl chloride/vinyl carboxylic acid ester copolymer resin as the main binder resin. The present invention aims to provide a gravure ink which has sufficient adhesion and is also excellent in printing suitability and post-processing suitability.

<Means for Solving the Problems> The present invention provides a gravure ink composition comprising a pigment, a vinyl chloride/'carboxylic acid vinyl ester copolymer resin, and an organic solvent as main components, wherein vinyl chloride in the resin contains 50 to 50% of vinyl chloride. 95% by weight, carboxylic acid vinyl ester 5~
A gravure ink composition containing 10 to 90% by weight of a copolymer resin consisting of 50% by weight and each unit of 001 to 5% by weight of a phosphoric acid ester having a carbon-carbon double bond copolymerizable with these. This is what we provide.

Further, the present invention provides that the vinyl chloride/vinyl carboxylic acid ester copolymer resin further contains 50 to 94% by weight of vinyl chloride, 1 to 45% by weight of vinyl carboxylic acid ester, and a copolymerizable compound 5 containing a hydroxyl group. The present invention provides a gravure ink composition containing at least 10% by weight of a copolymer resin composed of 1% by weight of each unit.

Hereinafter, the gravure ink composition according to the present invention will be specifically explained.

First, the vinyl chloride/'carboxylic acid vinyl ester copolymer used in the present invention is a resin obtained by copolymerizing vinyl chloride, carboxylic acid vinyl ester, and other copolymerizable compounds.

The carboxylic acid vinyl ester includes vinyl acetate,
Vinyl propionate, vinyl stearate, etc. can be used.

Further, as the copolymerizable compound, maleic acid,
Examples include α, β-unsaturated acids such as acrylic acid and methacrylic acid and their various esters, unsaturated alcohols such as allyl alcohol and polyvinyl alcohol, partially saponified products such as vinyl acetate, and vinylidene chloride. Among the copolymerizable compounds, especially those containing hydroxyl groups are
A copolymer resin containing up to 20% by weight is preferred from the viewpoint of pigment dispersibility.

On the other hand, the copolymer resin containing a phosphoric acid ester specified in the present invention is obtained by copolymerizing the above-mentioned vinyl chloride, vinyl carboxylic acid ester, and the following phosphoric acid esters.

Examples of phosphoric acid esters include 2-acid phosphooxine ethyl acrylate, 3-chloro-2-acid phosphooxy70vir acrylate, 2-acid phosphooxypropyl acrylate, 2-acid phosphooxyethyl methacrylate, 3-chloro-2- Examples include acid phosphooxypropyl methacrylate and 2-acid phosphooxypropyl methacrylate.

The content of these phosphate ester components in the copolymer is 0.01 to 5% by weight, more preferably 0.1 to 3% by weight.
Weight%. If it is less than 0.01% by weight, good adhesion cannot be obtained, and if it exceeds 5% by weight, the resulting copolymer will have poor solubility.

The vinyl chloride content of these two types of copolymers is
At least 50% by weight or more, more preferably 70-9%
It is 0% by weight. When the content of vinyl chloride is less than the above range, the solubility will be good, but the blocking resistance, chemical resistance, and water resistance will deteriorate.

On the other hand, as the carboxylic acid vinyl ester, vinyl acetate is particularly preferred for both types, and the content of the carboxylic acid vinyl ester must be at least 1% by weight, and if it is less than that range, the solubility will decrease. Furthermore, the viscosity of the solution increases, resulting in poor workability.

The above two types of copolymers can be polymerized by any conventional method, but the solution polymerization method is the method that can easily obtain a uniform copolymer.

The average degree of polymerization of both valve polymers is 100 to 900, more preferably 300 to 500. Note that if this average degree of polymerization is less than 100, good adhesion cannot be obtained;
If it exceeds this, the solubility will be poor and even if it is dissolved, the viscosity of the solution will be high.

When producing the gravure ink composition which is the object of the present invention using the above copolymer resin, the above-mentioned vinyl chloride/
The solid content weight ratio of the carboxylic acid vinyl ester copolymer and the phosphoric acid ester copolymer specified in the present invention,
10:90 to 90:10, more preferably 30:
It is necessary to use the ratio in the range of 70 to 85:15.

If the former resin ratio is less than 10% by weight, the pigment dispersibility will be insufficient; conversely, if the latter resin ratio is less than 10% by weight,
If it is less than 20%, adhesive dispersibility will be insufficient.

Note that it is also possible to use other resins in combination as long as the adhesiveness of the printing ink is not impaired. Examples of resins that can be used in combination include film-forming resins such as acrylic resins, polyurethane resins, and cellulose derivative resins, and hard resins such as rosin derivative resins and petroleum resins.

In addition, as pigments, general organic pigments, inorganic pigments, and even extender pigments used in printing inks can be used.
It is usually used in a range of 5 to 50% by weight.

In addition, the organic solvent is an organic solvent that dissolves the vinyl chloride/carboxylic acid vinyl ester copolymer resin mentioned above.
Ketones such as methyl ethyl ketone, esters such as ethyl acetate alone or mixed with aromatic hydrocarbons such as toluene, alcohols such as inpropyl alcohol, etc., are used to prepare the entire ink composition while adjusting drying properties, viscosity, etc. Medium, 40~
It is used in a range of 85% by weight.

When producing a printing ink composition using each of the above materials, the above-mentioned copolymer resin, organic solvent, and pigment are mixed and dispersed using a normal mixing and dispersing device to produce the printing ink. I can do it.

Furthermore, examples of additives include plasticizers such as dioctyl sebacate and octyltributyl citrate, lubricants such as polyethylene wax, anti-blocking agents such as fatty acid amide, and epoxy stabilizers, which may be added to the ink as necessary. It is possible to do so.

After the gravure ink thus obtained is printed with a gravure printing machine, it is often subjected to post-processing such as lamination in order to increase the added value of the printed matter. Dry lamination is a common method of laminating metallized films, and this is a lamination method in which various films are bonded together using an incyanate adhesive or the like. This lamination provides a surface protection function as well as a decorative effect on printed matter.

Furthermore, it is possible to see through the contents, and as a processing method to obtain printed matter with a metallic luster, the printed matter printed on aluminum vapor-deposited film is immersed in an aqueous solution such as hydrofluoric acid or sodium hydroxide. After performing an aluminum punching process to elute the aluminum in the areas not covered with ink, the above-mentioned lamination process may be performed. The gravure ink obtained according to the present invention has sufficient resistance to protect the aluminum portion covered by printing from the above-mentioned chemicals.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these.

<Example> Examples 1 to 12 and Comparative Examples 1 to 8 The following copolymers A, B, and C were used as binders and mixed and kneaded according to the materials and formulations shown in Table 1,
Manufactures gravure ink. Note that the numbers in the formulations indicate parts by weight.

Acid, 1% by weight> Comparative Example 9 A polyamide type gravure ink is manufactured according to the following formulation.

Phthalocyanine blue 10% by weight nitrified cotton 1
/4'' 1% by weight octyltributyl citrate 1% by weight Each of the ink compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 3 was used to prepare vapor deposited films having various wetting tensions, that is, aluminum vapor deposited polyester ( VMPET), aluminum-deposited polyboropyrene (V
140PP) and evaluated for pigment dispersibility, adhesion, and lamination suitability, and the results are shown in Table 1.

In addition, each evaluation method is based on the following method.

1) Pigment dispersion Each ink is printed on a specified film using a gravure proofing machine.The prints have sufficient gloss and density (◎), and those with the same gloss but slightly less density. (O)
Those with slightly inferior gloss and density but still marketable were evaluated as (Δ), and those with poor gloss and density were evaluated as (x).

2) Adhesiveness When each ink was printed on a designated film using a gravure proofing machine and left for one day, cellophane tape was applied to the printed surface and this was rapidly peeled off, the printed film did not come off at all. 80% or more remained on the film as (0), 50-80% remained on the film (△), and only 20% or less remained on the film as (x).

3) Dry lamination strength: Apply urethane adhesive (Atocoat 308A/D) to 2.7% of printed matter based on aluminum vapor-deposited polypropylene.
g/- coated, laminated with PP film using a dry laminating machine, aged at 40°C for 3 days, cut the sample into 15 mm width, and tested T with a peel tester manufactured by Yasuda Seiki Co., Ltd.
The mold peel strength (g/15ma+) was measured.

<Effects of the Invention> As specifically explained above using Examples, the gravure ink composition according to the present invention has excellent pigment dispersibility and suitability for lamination processing, and also reduces wetting tension due to oxidation, etc., which has been a problem in the past. It can be seen that the adhesive has sufficient adhesion even to aluminum foil or aluminum vapor-deposited film having a reduced adhesiveness.

Therefore, by using the gravure ink according to the present invention, it is possible to obtain high-quality printed matter that has excellent metallic luster and is suitable for post-processing such as aluminum punching or lamination.

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Claims (1)

[Scope of Claims] 1) A gravure ink composition containing a pigment, a vinyl chloride/vinyl carboxylic acid ester copolymer resin, and an organic solvent as main components, wherein the resin contains 50 to 9 of vinyl chloride.
5% by weight, 5% to 50% by weight of carboxylic acid vinyl ester, and 0.01% to 5% by weight of phosphoric acid ester having a carbon-carbon double bond copolymerizable with these units. A gravure ink composition containing 90% by weight. 2) The vinyl chloride/carboxylic acid ester copolymer resin further contains 50 to 94% by weight of vinyl chloride, 1 to 45% by weight of vinyl carboxylate ester, and 5 to 20% by weight of a copolymerizable compound containing a hydroxyl group. The gravure ink composition according to claim 1, containing at least 10% by weight of a copolymer resin consisting of each unit.