JP2007314682A - Ink composition having high luminance feeling and degradation-preventing capability for retort product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing ink composition for a laminate ink and a laminate can that hardly lose the high luminance even by the processes of heat-pressure bonding, heat-treatment and retort treatment. <P>SOLUTION: The high luminance ink composition comprising a high luminance pigment having scale-like form particles whose flaked glass surface is coated with a metal, a thermoplastic resin, and a metal chelate; the printing ink for laminates using the same; and the high luminance printing ink composition for laminated cans are provided. On the scale-like particle of the high luminance printing ink composition, a 0.02-0.7 μm thick coating layer made of a metal is formed on the flaked glass surface having an average thickness of 0.05-2 μm and an average particle size of 5-50 μm. The metal chelate used in the high luminance ink composition has its metal atom selected from the group consisting of aluminum, zirconium, titanium and zinc. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a high-intensity printing ink for laminate packaging materials that require boiling and retort, and a high-intensity for laminating cans used for metal cans such as beverage cans and food cans that require heat treatment such as retort and boiling. The present invention relates to a printing ink composition.

  In recent years, as disclosed in JP-A-05-96627 and JP-A-05-112361, a pre-printed film is pre-coated with an adhesive on the outer surface of a metal can of a beverage can or a food can, and the metal can The method of heat laminating to a metal plate for use has been carried out. The printing ink used in this method is, as disclosed in JP-A-7-216280, JP-A-11-172184, JP-A-2001-98192, adhesion to a film, residual solvent, anti-blocking property, and Polyurethane resins are often used as binder resins because of their good adhesion to films even under high hot water conditions such as heat sterilization. As a printing style, gravure printing is used because the same pattern can be produced in large quantities at low cost.

In recent years, scaly particles obtained by coating the surface of flake glass with a metal oxide having a higher refractive index than that of the glass of flake glass have been developed and put on the market. This is used to give a high brightness and improve the aesthetic appearance. There is a need for a laminating printing ink for packaging and a laminating can printing ink using the scaly particles. However, there has been a problem of loss of brightness after retorting, making it difficult to put it to practical use.
JP 7-216280 A JP 11-172184 A Japanese Patent Laid-Open No. 2001-98192

  An object of the present invention is to provide a laminating ink and a printing ink composition for laminating cans that do not easily lose a high brightness feeling even when subjected to thermocompression bonding, heat treatment, and retorting at a high temperature.

  The present invention finds that the metal chelate has an effect on the configuration using a high-luminance pigment that requires a high-luminance feeling among the printing ink composition for laminating and the printing ink composition for laminating cans. I found out to solve it.

That is, the present invention comprises a high-brightness printing ink composition comprising a high-brightness pigment having scaly particles formed by coating the surface of flaky glass with a metal, a thermoplastic resin, and a metal chelate, and The present invention relates to a laminating printing ink using the same, and a high brightness printing ink composition for laminating cans.
Moreover, the present invention provides a coating layer having a thickness of 0.02 to 0.7 μm made of metal on the surface of flake glass having a scale-like particle having an average thickness of 0.05 to 2 μm and an average particle size of 5 to 50 μm. It is related with the said high-intensity printing ink composition which is scale-like particle | grains characterized by forming.
The present invention also relates to a high brightness printing ink composition wherein the metal chelate is selected from the group consisting of aluminum, zirconium, titanium or zinc.

Furthermore, this invention relates to the said high-intensity printing ink composition whose metal chelate is 0.05-10.0 mass%.
Furthermore, this invention relates to the said printed matter printed on the polyester film and the nylon film using the high-intensity printing ink composition.
Furthermore, the present invention provides a film-laminated laminate laminate obtained by thermocompression bonding a film or a metal plate with an adhesive to a printed matter printed using a high-brightness printing ink composition, and the laminate laminate. The present invention relates to a packaging container made by processing, and a beverage can or a food can.
Furthermore, the present invention comprises a high-brightness printing ink composition for laminate cans, comprising a high-brightness pigment having a scaly particle formed by coating the surface of flaky glass with a metal, a thermoplastic resin, and a metal chelate Related to things.

  The printing ink composition provided by the present invention does not lose brightness even when it is subjected to processing such as a retort process in a laminate for packaging, or a printed matter containing scale-like particles in a laminate can, and has excellent ink stability. Is.

  About each component in the high-brightness printing ink composition characterized by containing a high-brightness pigment having a scaly particle formed by coating the surface of the flaky glass of the present invention with a metal, a thermoplastic resin and a metal chelate, This will be described below.

  The thermoplastic resin used in the printing ink of the present invention has a softening point of 200 ° C. or less, preferably 180 ° C. or less. For example, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer , Polyethylene, polypropylene, polyacetal, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polystyrene, polyacrylate ester, polyamide, ethyl cellulose, epoxy resin, acrylic resin, xylene resin, ketone resin, petroleum resin, There are synthetic rubbers such as rosin or its derivatives, coumarone indene resin, terpene resin, polyurethane resin, styrene-butadiene rubber, polyvinyl butyral, nitrile rubber, acrylic rubber, ethylene-propylene rubber, and these resins are used alone or in two kinds. For mixing above Can be. Preferably, it is a polyurethane resin alone.

The high-brightness pigment in the present invention uses glass flakes of scaly particles, and the metal oxide coating of the glass flakes can obtain various brilliant interference colors by changing the thickness of the layer. Therefore, various colors ranging from achromatic to chromatic are developed by adjusting the layer thickness.
The scaly particles are obtained by forming a coating layer made of a metal oxide and having a thickness of 0.02 to 0.7 μm on the surface of a flaky glass having an average thickness of 0.05 to 2 μm and an average particle size of 5 to 50 μm. Preferably there is. The content of the glossy pigment in the ink composition is preferably 0.1 to 50% by weight.

When a metal chelate compound is blended in the printing ink of the present invention, the printed ink is in a dry state, and the functional group such as amino group, hydroxyl group and carboxyl group of the resin and the metal atom are coordinated to form a crosslinked structure. Forming and increasing the cohesive strength of the printing ink coating. As the metal component of the metal chelate compound, metals such as aluminum, zirconium, titanium, zinc, iron, cobalt, tin, chromium and nickel are usually used, but aluminum, zirconium, titanium and zinc are preferable. These metal chelates can be used alone or in admixture of two or more.
Further, the addition amount of the metal chelate is 0.05 to 10.0% by weight, the effect is difficult to obtain when the addition amount is 0.05% or less, and the stability with time such as increase in viscosity when 10.0% or more is inferior. Therefore, it is preferably 0.1 to 5.0% by weight.

Examples of the solvent to be blended in order to have a function required for the ink of the present invention include commonly used solvents. Alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol (IPA), ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, aliphatic hydrocarbons such as n-hexane, n-heptane, toluene, Examples include aromatic hydrocarbons such as xylene, glycol derivatives such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, and esters such as ethyl acetate and isopropyl acetate. These can be used alone or in admixture of two or more, but from the standpoint of solubility and drying properties, a mixed solvent is used, preferably 10 to 80% by weight.

  Examples of the colorant blended to have the function required for the ink of the present invention include organic and inorganic pigments and dyes used in general inks, paints, and recording agents. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, dictopyrrolopyrrole, isoindoline, etc. Pigments. It is preferable to use C.I. Pigment NoYellow83 for the indigo ink and for the transparent yellow ink from the viewpoint of cost and light resistance.

  Examples of the inorganic pigment include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, bengara, aluminum, mica (mica), and the like. From the viewpoints of cost and coloring power, it is preferable to use titanium oxide for white ink, carbon black for black ink, aluminum for silver ink, and mica for pearl ink. Aluminum is in the form of powder or paste, but is preferably used in the form of paste from the viewpoint of handling and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and concentration.

  The colorant is preferably contained in an amount sufficient to ensure the density 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. Moreover, a coloring agent can be used individually or in combination of 2 or more types.

  In order to stably disperse the pigment in the organic solvent, it is possible to disperse the resin alone, but it is also possible to use a dispersant in order to disperse the pigment stably. As the dispersant, anionic, nonionic, cationic, amphoteric surfactants can be used. The dispersant is preferably contained in the ink in an amount of 0.05% by weight or more based on the total weight of the ink from the viewpoint of the storage stability of the ink and 5% by weight or less from the viewpoint of the suitability for lamination. .1 to 2% by weight. Further, if necessary, leveling agents, antifoaming agents, waxes, antiblocking agents, and plasticizer additives are also optionally added, and are preferably contained in the ink in an amount of 5% by weight or less from the viewpoint of proper lamination.

  The ink of the present invention can be produced by dissolving and / or dispersing a resin, a colorant and the like in an organic solvent. Specifically, an ink can be produced by producing a pigment dispersion in which a pigment is dispersed in an organic solvent with a resin, and blending the obtained pigment dispersion with other compounds as required. .

  In addition, the ink of the present invention may contain a high-brightness pigment and / or a metal chelate, which is blended at the time of ink production, added immediately before using the ink, or diluted to a viscosity suitable for printing with a diluent solvent. For example, there is a method of adding to the diluted ink. The content of the high brightness pigment and / or the metal chelate varies depending on whether the calculation is based on the ink (base ink) or the diluted ink. In the present invention, the content is calculated based on the ink (base ink).

  The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the grinding media of the disperser, the filling rate of the grinding media, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As a disperser, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used. In the case where bubbles or unexpectedly large particles are included in the ink, it is preferably removed by filtration or the like in order to reduce the quality of the printed matter. A conventionally well-known filter can be used.

  The ink viscosity produced by the above method is in the range of 10 mPa · s or more from the viewpoint of preventing the pigment from settling and being appropriately dispersed, and 1000 mPa · s or less from the viewpoint of workability efficiency during ink production or printing. preferable. In addition, the said viscosity is a viscosity measured at 25 degreeC with the Tokimec B-type viscometer. The viscosity of the ink can be adjusted by appropriately selecting the type and amount of raw materials used, for example, a polyurethane resin, a colorant, an organic solvent, and the like. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

As the hue of the ink of the present invention, there are five basic colors of yellow, red, indigo, black, and white, depending on the type of colorant used, and red (orange) and grass (colors outside the process gamut) There are three colors, green) and purple. Further, transparent yellow, peony, vermilion, brown, gold, silver, pearl, almost transparent medium for adjusting color density (including extender pigments if necessary), etc. are prepared as base colors. The base ink of each hue is diluted with a diluting solvent to a viscosity and density suitable for gravure printing, and supplied alone or mixed to each printing unit.

  Next, a bonded metal plate using the ink of the present invention will be described. In the polyester film-bonded metal plate, the polyester film to be bonded to the metal plate may be a polyester film, but 75 to 100% of the ester repeating units are preferably composed of ethylene terephthalate units. Examples of the ester unit other than the ethylene terephthalate unit include ester units such as phthalic acid, isophthalic acid, succinic acid, and adipic acid. The polyester film preferably has a surface subjected to surface treatment such as corona discharge treatment in order to improve adhesion to the ink of the present invention and further to the adhesive.

  Examples of the metal plate used for the bonded metal plate of the present invention include hot rolled steel plate, cold rolled steel plate; hot dip galvanized steel plate, electrogalvanized steel plate, iron-zinc alloy plated steel plate, zinc-aluminum alloy plated steel plate, nickel- Zinc alloy-plated steel sheet, nickel-tin alloy-plated steel sheet, tinplate, chrome-plated steel sheet, aluminum-plated steel sheet, turn-plated steel sheet, nickel-plated steel sheet, etc .; stainless steel, tin-free steel, aluminum plate, copper plate, titanium plate, etc. These metal materials and, if necessary, those subjected to chemical conversion treatment such as phosphate treatment, chromate treatment, composite oxide film treatment, etc. can be used.

  The present invention can be produced, for example, by the following method. First, the ink of the present invention is applied to the corona discharge-treated surface of a polyester film having a thickness of about 5 to 30 μm by a gravure printing method so as to have a dry film thickness of about 0.3 to 3 μm. Dry at 40-80 ° C. until free. Next, an adhesive is applied to the printing surface of the polyester film on which the ink layer obtained as described above is formed by a coating means known per se such as spray coating, roll coating, gravure coating, etc. Dry at temperature. The polyester film having the gravure ink layer and the adhesive layer obtained as described above is bonded to a metal plate and heated and laminated at a temperature of about 150 ° C. to 250 ° C. for a short time (usually about 2 seconds or less). Can be manufactured.

  Next, a description will be given of a packaging laminate using the ink of the present invention. The laminate laminate of the present invention comprises an object to be printed, the ink of the present invention, a sealant, and an anchor coat agent or adhesive used when laminating the sealant as necessary. It can be obtained by printing the ink of the present invention on a substrate by gravure printing or flexographic printing, and laminating a sealant by a method such as extrusion lamination (extrusion lamination), dry lamination, non-sol dry lamination, etc. I can do it. In addition, a processed product obtained by printing an ink other than the present invention on a substrate to be printed by the above-described method, finally printing the ink of the present invention, and laminating by the above-described method can also be exemplified as the packaging laminate of the present invention.

  Examples of the substrate to be used for the laminate laminate of the present invention include plastic and paper generally used for gravure printing or flexographic printing. Plastics include uniaxially or biaxially stretched or unstretched films or sheets such as nylon, polyester, polypropylene, polyethylene, etc. These are generally subjected to surface treatments such as corona discharge treatment and low temperature plasma treatment. It has been subjected. Furthermore, a film or sheet made of cellophane, moisture-proof cellophane, vinyl chloride resin, vinylidene chloride resin, styrene resin, vinyl acetate resin, vinyl alcohol resin, polyamide or the like, or a laminate thereof can also be mentioned. .

  Examples of the sealant used in the present invention include the plastic film or sheet or aluminum foil. In particular, as the resin to be extruded (extruded laminate), low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer or saponified product thereof, ethylene-acrylic acid Examples thereof include a copolymer, an ethylene-ethyl acrylate copolymer, and polypropylene.

  Examples of the anchor coating agent or the adhesive used as necessary in the laminated product of the present invention include those commonly used for laminating. Examples of the anchor coating agent include polyisocyanate series, polybutadiene series, polyethyleneimine series, and organic titanium series. Examples of the adhesive include urethane and modified polyolefin.

  The laminated product of the ink of the present invention is formed into a container such as a bag, and is used by being filled with food / beverage products, medical products, medical instruments, cosmetics, and the like.

The present invention will be described more specifically with reference to examples. Hereinafter, both “parts” and “%” are based on weight.
In addition, a hydroxyl group is the number of mg of potassium hydroxide required in order to neutralize the hydroxyl group contained in 1g of resin, and is the value performed according to JISK0070. The amine value is the number of mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize the amino group contained in 1 g of resin. The method for measuring the amine value was as described below. The molecular weight was determined as a polystyrene-converted molecular weight by measuring the molecular weight distribution using a GPC (gel permeation chromatography) apparatus. The viscosity was measured at 25 ° C. with a Tokimec B-type viscometer.

(Synthesis example)
147.1 parts of polyester diol (PMPA4000) having a number average molecular weight (hereinafter referred to as Mn) of 4,000 obtained from adipic acid and 3-methyl-1,5-pentadiol, 97.0 parts of polypropylene glycol (PPG2000) of Mn2000, 39.7 parts of isophorone diisocyanate and acetic acid 90 parts of ethyl was reacted at 90 ° C. for 6 hours under a nitrogen stream to obtain 373.8 parts of a solvent solution of a terminal isocyanate prepolymer. Next, 15.8 parts of isophoronediamine, 0.3 part of 2-hydroxyethylethylenediamine, 0.1 part of di-n-butylamine, 330 parts of ethyl acetate and 280 parts of isopropyl alcohol were mixed with 473 parts of the solvent solution of the resulting terminal isocyanate prepolymer. Gradually added at room temperature and then reacted at 50 ° C. for 1 hour to obtain a polyurethane resin solution having a solid content of 30%, an amine value of 1.0 mg KOH / resin, 1 g of hydroxyl value, 0.2 mg KOH / resin of 1 g, and a viscosity of 8 P at 25 ° C. .

[Example]
For the high-intensity ink, a mixture of 15 parts of glass flakes, 50 parts of a polyurethane resin solution, 25 parts of methyl ethyl ketone, and 25 parts of toluene was dispersed with stirring to obtain a high-intensity printing ink base.

  In order to adjust the viscosity at the time of printing after adding the chelating agent in Table 1 to 100 parts of each of the base inks, a mixed solvent consisting of 35% methyl ethyl ketone, 50% toluene, and 15% isopropanol was used at 25 ° C. Dilution was carried out so that the viscosity measured with Cup No. 3 was 18 seconds to obtain a high-intensity printing ink (diluted ink).

Using the diluted high-intensity printing ink (diluted ink) and a gravure printing machine equipped with a gravure solid plate having a plate depth of 35 μm, a corona discharge-treated polyethylene terectrate film “E5100” (Toyobo ( The product was printed on a corona discharge treated surface of a product name, and dried at a dryer temperature of 40 ° C to 50 ° C to obtain a printed film.
Next, a thermosetting epoxy resin adhesive was applied to the 35 μm high-brightness ink printing part of the printing film so that the dry coating film weight was 10 g / m ² and preliminarily dried.
Next, a tin-free steel plate is used as the metal plate for the can, and the printed film provided with the adhesive layer and the metal plate for the can are overlaid so that the adhesive layer is in contact with the metal plate for the can, and the laminator is used to roll Heat lamination was performed at a pressure of 4 kg / cm 2 and a roll temperature of 200 ° C., and further heat-treated at 200 ° C. for 2 minutes or at 230 ° C. for 2 minutes to obtain a polyester film bonded metal plate. Next, using the polyester film-laminated metal plate, a hot water resistance test was performed, and luminance changes before and after the hot water resistance test were visually evaluated. Tables 1 and 2 show the results. The evaluation method was performed as described later. Furthermore, the state of the ink was evaluated after high temperature printing ink (diluted ink) after printing film preparation was carried out at 40 ° C. for 1 day, and the results are shown in Tables 1 and 2.

[Examples and Comparative Examples 1 to 3 and Reference Example]
An ink (base ink) was prepared in the same manner as in the example. Furthermore, the isocyanate shown in Table 2 and the silane coupling agent were mix | blended, and it diluted with the mixed solvent similar to Example 1, and obtained high-intensity ink (diluted ink). Using the diluted ink, printing and laminating were carried out in the same manner as in Example to obtain a polyester film bonded metal plate. The same evaluation was performed for each. The results are shown in Tables 1 and 2.

The method for measuring the amine value is as follows.
[Method for measuring amine value]
Weigh 0.5-2 g of sample accurately. (Sample amount: Sg) 30 mL of neutral ethanol (BDG neutral) is added to a precisely weighed sample and dissolved. The obtained solution is titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The point at which the color of the solution changed from green to yellow was taken as the end point, and the amine value was determined by the following formula (1) using the titration amount (AmL) at this time.
[Formula 1]

The conditions for each performance evaluation are as follows.
[Brightness change before and after hot water test]
The prepared polyester film-laminated metal plate was retorted at 125 ° C. for 30 minutes, and the appearance (change in luminance) was evaluated with a magnifying glass in five stages. Good (◯), slightly good (○ △), slightly bad (Δ), bad (ΔX), very bad (×).

[Ink stability]
After the printing film was created, the separation, precipitation, and fluidity of high-intensity printing ink (diluted ink) after 1 day at 40 ° C. were visually evaluated on a five-point scale. Good (◯), slightly good (○ △), slightly bad (Δ), bad (ΔX), very bad (×).

Table 1

Claims (7)

A high-brightness printing ink composition comprising a high-brightness pigment having a scaly particle formed by coating the surface of a flaky glass with a metal, a thermoplastic resin, and a metal chelate. The scale-like particles formed by coating the surface of the flaky glass with a metal material have a thickness of 0.02 made of a metal material on the surface of the flaky glass having an average thickness of 0.05 to 2 μm and an average particle diameter of 5 to 50 μm. The high-brightness printing ink composition according to claim 1, which is a scaly particle having a coating layer of ˜0.7 μm. The high brightness printing ink composition according to claim 1 or 2, wherein the metal chelate is selected from the group consisting of aluminum, zirconium, titanium or zinc. The high-luminance printing ink composition according to any one of claims 1 to 3, wherein the content of the metal chelate is 0.05 to 10.0 mass%. The printed matter printed on the polyester film and the nylon film using the high brightness printing ink composition according to any one of claims 1 to 4. A film-laminated laminate laminate obtained by thermocompression bonding with a film or a metal plate via an adhesive on a printed matter printed using the high-luminance printing ink composition according to any one of claims 1 to 5, and the laminate Packaging containers made by processing laminates, and beverage or food cans. The high for a laminate can according to any one of claims 1 to 6, comprising a high-intensity pigment having scaly particles formed by coating the surface of flake glass with a metal, a thermoplastic resin, and a metal chelate. Luminance printing ink composition.