JP6066677B2 - Liquid ink - Google Patents

Description

  The present invention relates to a liquid ink composition that can be generally used for various heat shrink films in gravure printing, and a printed matter using the ink.

  For heat shrink labels for beverage containers by gravure printing, shrink styrene films, shrink polyester films, shrink polyvinyl chloride films and the like are mainly used. Among these, since the shrink styrene film has poor solvent resistance, acrylic resin solvent-based inks mainly composed of alcohol components are mainly used for printing. In view of solvent resistance, water-based acrylic inks may be used, but existing water-based inks have poor adhesion to styrene films and have not been put into practical use.

  On the other hand, the use of alcohol-based inks other than acrylic resin such as nitrified cotton, cellulose ester resin, polyurethane resin, and polyvinyl butyral resin is also conceivable, but the adhesiveness with the shrink styrene film is inferior and it is difficult to adopt. Therefore, the actual situation is that a special alcohol solvent ink is used for the shrink styrene film.

  Under such circumstances, printing manufacturers use dedicated inks suitable for each heat shrink film, and complicated production operations such as handling small lots and replacing inks are necessary. In recent years, therefore, there has been a growing demand for integrated general-purpose inks that can be used for all three types of heat shrinkable films.

  On the other hand, a printing ink composition containing methylcyclohexane in the ink composition to improve adhesion to various shrink films has been disclosed (for example, Patent Document 1). However, the ink composition to which methylcyclohexane is added cannot be said to have sufficient drying properties, and the effect of improving the adhesion to various shrink films is not sufficient, and therefore more effective improvement measures are required.

JP 2009-286974 A

  An object of the present invention is to provide a liquid ink having improved adhesion to various shrink films such as a shrink vinyl chloride film, a shrink styrene film, and a shrink polyester film, and improved basic printing properties and post-processing physical properties. There is. Moreover, it is providing the printed matter using this ink, and a processed material after that.

  The present invention has found a liquid ink that satisfies the basic properties of printability and post-processing physical properties while improving adhesion to various shrink films such as shrink PVC film, shrink styrene film, and shrink polyester film. is there. As a result of intensive studies to solve the above-mentioned problems, the present inventors have formulated a proper amount of a specific cyclic ester compound in the solvent component of the liquid ink composition, and post-processing such as drying properties after printing and blocking resistance. The inventors have found that the adhesion to various shrink films such as a shrink vinyl chloride film, a shrink styrene film, and a shrink polyester film is improved to one leaf while satisfying the physical properties.

  That is, the present invention is, firstly, a liquid ink having a binder resin and a solvent, wherein the binder resin is a urethane resin and / or an acrylic resin, and the solvent component has 4 to 10 carbon atoms. A liquid ink comprising 0.01 to 8.0% by weight of a cyclic ester compound is provided.

  Secondly, the present invention provides a printed matter obtained by printing the above-described liquid ink.

  The present invention can improve adhesion to various shrink films such as shrink PVC film, shrink styrene film, and shrink polyester film while maintaining the drying property important as printability and the blocking resistance affecting post-processing properties. Liquid ink is obtained.

  The present invention is a liquid ink having a binder resin and a solvent, wherein the binder resin is a urethane resin and / or an acrylic resin, and a cyclic ester compound having 4 to 10 carbon atoms in the solvent component, Provided is a liquid ink containing 0.01 to 8.0% by weight of the total weight of the ink.

  In the liquid ink of the present invention, a polyurethane resin and / or an acrylic resin is preferable as a resin component, and these resins may be used alone or in a plurality of types.

  The number average molecular weight of the polyurethane resin and acrylic resin used in the liquid ink of the present invention is preferably in the range of 15,000 to 100,000. When the number average molecular weight of the polyurethane resin and acrylic resin is less than 15,000, the resulting ink composition tends to have low blocking resistance, chemical resistance, and the like. There is a tendency that the viscosity of the obtained ink composition becomes high and a predetermined printing density cannot be obtained.

  The liquid ink of the present invention can further contain nitrified cotton as a resin component. Pigment dispersibility and drying properties are improved by using nitrified cotton mixed with polyurethane resin and acrylic resin. The content of nitrified cotton is preferably 1 to 10% by weight of the total ink weight.

  Examples of other resins that can be used in combination with the binder resin include vinyl chloride / vinyl acetate copolymers, rosin resins and modified products thereof, ketone resins, cellulose resins, polyester resins, and polyamide resins.

  The content of the binder resin component in the liquid ink of the present invention is preferably, for example, 5 to 25% by weight based on the total weight of the gravure ink.

  For example, in the case of gravure printing, the content of the binder resin component in the liquid ink of the present invention is 5% by weight or more based on the total weight of the ink from the viewpoint of sufficient adhesion to the printing body of the gravure ink, From the viewpoint of moderate ink viscosity and work efficiency at the time of ink production and printing, it is preferably 25% by weight or less, and in the case of flexographic printing, it should be 5% by weight or more and 30% by weight or less based on the total weight of the flexographic ink. preferable.

  In the liquid ink of the present invention, a cyclic ester compound having 4 to 10 carbon atoms as an essential component together with an organic solvent as a volatile component is 0.01 to 8.0% by weight, preferably 0.01 to 5% of the total weight of the ink. 0.0% by weight can be contained.

  Specific examples of the cyclic ester compound include γ-butyrolactone having 4 carbon atoms, δ-valerolactone having 5 carbon atoms, ε-caprolactone having 6 carbon atoms, oxylican-2-one having 7 carbon atoms, carbon Examples include several η-capryllactone, nine oxecan-2-one having 9 carbons, and oxacycloundecan-2-one having 10 carbons.

  By adding a small amount of the cyclic ester during the blending of the ink, after printing the ink, the solvent attack on the film surface in the drying step is uniformly increased, and the adhesion of the ink coating is improved. This effect is remarkable in the shrink styrene film. When the film is subjected to a solvent attack, there are problems such as shrinkage whitening and film breakage. However, in the case of the cyclic ester, the adhesiveness is improved by adding a small amount, so that the post-processing characteristics of the shrink film are affected. Absent. If the added amount of the cyclic ester with respect to the total weight of the ink exceeds 8.0%, the drying property is lowered and the printability is affected. In addition, the solvent component tends to remain, leading to odor problems.

  The liquid ink of the present invention can contain an alcohol solvent as a solvent component. The alcohol solvent used in the printing ink of the present invention is preferably one selected from methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol. In particular, ethanol, 1-propanol, and 2-propanol are preferable from the viewpoint of drying speed, odor, and safety to the human body. The alcohol solvent may be added in an amount of 50% by weight or more based on the total weight of the ink.

  Examples of the colorant used in the liquid ink of the 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. Indigo ink is copper phthalocyanine, and transparent yellow ink is C.I. I. Pigment No Yellow 83 is preferably used.

  For example, pigment C.I. I. Black7, Y12, Y13, Y14, Y17, Y83, Y74, Y-154, Y180, R57: 1, R122, R48: 1, R48: 2, R48: 3, R53: 1, R146, R-150 R-166, R170, R184, R185, V19, V23, V32, O13, O16, O34, G7, G36, B15: 3, B15: 4, W6 and the like.

  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.

  The pigment content is preferably 1 to 30% by weight, particularly preferably 5 to 20% by weight, based on 100% by weight of the ink.

(Normal production method)
The production of the gravure ink of the present invention is, for example, a polyurethane resin, a coloring pigment, an extender pigment, a solvent, and, if necessary, an additive such as an antistatic agent, an antiblocking agent, a plasticizer, ink fluidity and Normal printing inks such as ball mills, attritors, and sand mills that use surfactants to improve dispersibility or resins that are compatible with polyurethane resins in a range where thickening and gelation do not occur over time. This is done by kneading using a production apparatus. In particular, the addition of an antistatic agent is effective in suppressing static electricity troubles during printing, called whiskers and lightning stripes, which are likely to occur when using ester solvents and ketone solvents.

  The present invention provides a printed matter and a post-processed product obtained by printing the above-described liquid ink.

  Hereinafter, the present invention will be specifically described with reference to examples. In addition, "part" in an Example represents a mass part.

(Preparation of polyurethane resin A)
Neo having a hydroxyl value of 56.1 (mg-KOH / g) and a molecular weight of 2,000 in a 1 liter four-necked flask equipped with a stirrer, thermometer, Dimroth type reflux condenser, and nitrogen gas inlet tube 171 parts of a condensate of pentyl glycol and adipic acid, 171 parts of polypropylene glycol having a hydroxyl value of 56.1 (mg-KOH / g) and a molecular weight of 2,000 were charged, and nitrogen gas was allowed to flow and the mixture was stirred at 70 ° C. The temperature rose. Subsequently, 77 parts of isophorone diisocyanate was added and reacted at 90 ° C. until the NCO%, which is the residual ratio of isocyanate groups, reached 3.4, and a linear urethane prepolymer (A1) having aliphatic isocyanate groups at both ends was obtained. Obtained.

  Subsequently, 157 parts of ethyl acetate (B1), 893 parts of isopropyl alcohol (C1), isophoronediamine were added to a 2 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. (D1) 30 parts and dinormal butylamine (E1) 1.6 parts were added, and it heated up to 40 degreeC. Next, part of the linear urethane prepolymer (A1) 419 is added and reacted at 40 ° C. for 4 hours, and the amino group (d1) in the diamine (D1) and the amino group (e1) in the monoamine (E1), The equivalent ratio [(d1 + e1) / (A1)] to the aliphatic isocyanate group (a1) in the linear urethane prepolymer (A1) is 1.05, and the organic solvent (B1) having no active hydrogen and the alcohol type A polyurethane polyurea resin solution A having a weight ratio [(C1) / (B1)] to the solvent (C1) of (85/15) was obtained.

Examples 1-16, Comparative Examples 1-5
(Ink preparation method)
Mixtures mixed at the blending ratios shown in Table 1 and Table 2 were kneaded using a dyno mill (manufactured by Willy et Bacofen), and inks described in Examples 1 to 16 and Comparative Examples 1 to 5 were prepared.

  The following evaluation was implemented about Examples 1-16 ink and Comparative Examples 1-5 ink which were obtained above.

(Adhesion to film)
The inks listed in Tables 1 and 2 were developed on the treated surface of each shrink film with a bar coater # 4. After the Nichiban cellophane tape 18 mm width was brought into close contact with the color development surface, the cellophane tape was peeled off vigorously in the vertical direction, and the area ratio of the ink film adhering to the cellophane tape was visually evaluated.
If the area ratio of the ink adhering to the cellophane tape is less than 30%, it can be judged as a practical level, but it is preferable that the ink does not adhere to the cellophane tape.
(Evaluation)
5: Area ratio of ink adhering to cellophane tape 0%
4: Area ratio of ink adhering to cellophane tape is less than 10% 3: Area ratio of ink adhering to cellophane tape is less than 30% 2: Area ratio of ink adhering to cellophane tape 30% or more 1: Ink adhering to cellophane tape More than 80% area ratio

(Solvent attack)
The inks listed in Tables 1 and 2 were diluted with a mixed organic solvent having the same ratio used for ink preparation, and diluted with Zaan Cup No. 3 manufactured by Kogaisha Co., Ltd. for 16 seconds. With a dropper, 2 cc of ink was dropped on the corona discharge treated surface of a shrink styrene film (Bonset EPS-35 manufactured by C-I Kasei Co., Ltd.) and left for 5 minutes. After the film was dried, the haze value of the film in contact with the ink was measured with a haze meter NDH500 (manufactured by Nippon Denshoku Industries Co., Ltd.). When the haze value of the film is low, it is judged that the solvent attack property is good.
(Evaluation)
5: Haze value 5 or less Visually transparent 4: Haze value 5 or more and 10 or less Visually opaque 3: Haze value 10 or more and 15 or less Visually opaque 2: Haze value 15 or more and 20 or less Visually opaque 1 : Haze value of 20 or more

(Drying)
The inks listed in Tables 1 and 2 were diluted with the same ratio of mixed organic solvents used for ink preparation, and diluted with Zaan Cup No. 3 manufactured by Kotosha Co., Ltd. for 15 seconds. A gravure plate (plate depth: 25 micrometers, 100% solid plate) was set on a CONVERDIC gravure 8-color printing machine (Dainippon Ink Chemical Co., Ltd.), and the inks listed in Tables 1 and 2 were dried at a drying speed of 80. Printing is performed at a set printing speed for 30 minutes under a shrinkage styrene film (Bonset EPS-35 manufactured by C-I Kasei Co., Ltd.) under the conditions of ° C. and a dry air volume of 70 m ³ / min. Black paper is placed on a guide roll directly above the dryer, and the amount of ink transferred from the printing surface to black paper is evaluated.
(Evaluation)
5: Not transferred at all. The ink is completely dry.
4: Very little ink transfer is observed. Since the ink is almost dry, there is no practical problem.
3: Slight ink transfer is observed. Ink drying failure has occurred.
2: Ink transfer is clearly observed. Ink drying failure has occurred.
1: Ink transfer is observed on a large scale. Ink drying failure has occurred.

(Blocking resistance)
The ink described in Table 1 and Table 2 was applied to the corona discharge treated surface of each shrink film using Bar Coder # 4. Next, another untreated surface of the same shrink film was adhered to the coated surface of the ink described in Table 1 and Table 2. A pressure of 0.5 MPa was applied to the two-layered film test piece and left for 24 hours in an environment of a temperature of 50 ° C. and a relative humidity of 80%. After the film was air-cooled to room temperature, the two test pieces were peeled off. When the ink film on the coated surface is not transferred to the other film, it is judged as good.
(Evaluation)
5: The ink film does not transfer to the other film surface at all 4: The ink film transfers about 10% to the other film surface 3: The ink film transfers about 20% to the other film surface 2: Ink film Is transferred to the other film surface by about 30% 1: the ink film is transferred to the other film surface by about 40% or more

The raw materials in the table are as follows.
Fastogen Blue 5380 (manufactured by DIC Corporation): C.I. I. Pig.
No. = B-15: 3
Nitrified cotton L1 / 4 Solid content Nitrogen content 10.7 to 11.4%, Solution concentration 25.0%, drop time showing viscosity 3.0 to 8.9 seconds (JIS K-6703 industrial cellulose) Nitrocellulose Dianal BR-90 Weight average molecular weight 230,000, Tg65 ° C. Solid content (Mitsubishi Rayon Co., Ltd.) acrylic resin n-propyl acetate (Daicel Co., Ltd.)
Product Name Caprolactone Monomer (Daicel Co., Ltd.) ε-Caprolactone Product Name GBL (BASF Co., Ltd.) γ-Butyrolactone Shrinkage Polyester (PET) Film Space Clean S-7053 (Toyobo Co., Ltd.)
Shrink polystyrene (OPS) film Bonset EPS-35 (Cai Kasei Co., Ltd.)
Shrink PVC film Hishilex 502 (Mitsubishi Plastics)

  From the above results, the liquid ink of the present invention is capable of various shrinkage such as shrinkage PVC film, shrinkage styrene film, shrinkage polyester film, etc. while maintaining the drying property important as printability and blocking resistance affecting post-processing properties. It turns out that the adhesiveness with respect to a film improves compared with the conventional ink.

  The liquid ink of the present invention is a general-purpose type ink that has improved adhesion to various shrink films in gravure, flexo, silk screen printing, beverage labels, shrink cap seals, food packaging materials, sanitary, cosmetics, and electronic parts. It can be widely deployed in flexible packaging applications for industrial products such as industrial products.

Claims (3)

A liquid ink having a binder resin and a solvent, wherein the binder resin is a urethane resin and / or an acrylic resin, and a cyclic ester compound having 4 to 10 carbon atoms in the solvent component is 0.01 to 8 Liquid ink characterized by containing 0.0% by weight, wherein the liquid ink contains (46.0 / 105.0) × 100 % by weight or more of the total amount of alcohol solvent.   The liquid ink according to claim 1, wherein the binder resin contains nitrified cotton. A printed matter obtained by printing the liquid ink according to claim 1.