JP2014065786A - Laminate ink composition for soft packaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, in acknowledgment of the need for environmentally conscious measures, a laminate ink composition for soft packaging exhibiting, even when solubilized into an ester solvent or alcohol solvent alone without using hydrocarbon-based organic solvents led by aromatic hydrocarbons or ketone-based solvents, a favorable solubility and also excellent in terms of fluidity, adhesiveness with a printing target, and boil-retort suitability.SOLUTION: The provided laminate ink composition for soft packaging not only includes, in acknowledgment of the need for environmental friendliness, neither hydrocarbon-based organic solvents led by aromatic hydrocarbons nor ketone-based solvents and exhibits high solubilities even with ester solvents and alcohol solvents while meeting demands of printability specific to soft packaging applications mainly targeting non-absorbent print target foundations such as films, etc. and of fundamental ink characteristics on printing occasions but also takes into account the balance of admixture components comprising a resin and a volatile solvent component.

Description

  The present invention relates to a laminating ink composition for soft packaging that is used for a package that is generally laminated for food use in gravure printing.

Printing inks used for laminating applications, mainly used in the manufacture of soft packaging materials, are mainly vinyl chloride resin / urethane from the viewpoint of required performance such as adhesion to printed materials, laminating strength, and suitability for boil and retort. Gravure inks combining resins or cellulose derivative resins / urethane resins have been used.
As the cellulose derivative resin, cellulose acetate propionate (hereinafter referred to as CAP), cellulose acetate butyrate (hereinafter referred to as CAB), and nitrocellulose (hereinafter referred to as NC) have been mainly used. These cellulose derivative resins are inferior in fluidity in CAP and CAB, and inferior in adhesion to a printing medium and suitability for boil and retort in NC compared with vinyl chloride resin. For this reason, in consideration of these performance aspects, an ink combining vinyl chloride resin / urethane resin has been disclosed for the flexible packaging application, which has become the mainstream in the industry (for example, see Patent Document 1).

  On the other hand, with the growing awareness of the environment, such as occupational health during printing and the safety of packaging materials, esters / alcohols that do not contain aromatic hydrocarbons and other hydrocarbon organic solvents and ketone solvents A mixed-type gravure ink for laminating is disclosed (for example, see Patent Document 2). In addition, in order to obtain an ester / alcohol mixed type by a combination of vinyl acetate resin / urethane resin, the vinyl acetate resin itself has low solubility in an ester solvent and an alcohol solvent, so there is a problem in printability such as transferability. There is. Therefore, it is desired to select a resin having good solubility in an ester solvent or an alcohol solvent and excellent printability.

JP 2005-298618 A JP 2008-265032 A

  The object of the present invention is to be conscious of dealing with environmental consciousness, without using hydrocarbon organic solvents such as aromatic hydrocarbons and ketone solvents, and having good solubility only with ester solvents and alcohol solvents. Another object of the present invention is to provide a laminate ink composition for soft packaging having excellent fluidity, adhesion to a printing medium, and suitability for boil and retort.

  The present invention is intended for environmentally friendly applications such as aromatic hydrocarbons, while satisfying the printing suitability for flexible packaging mainly for non-absorbing raw materials such as films and the basic characteristics of ink at the time of printing. Laminated ink composition for flexible packaging that does not contain hydrocarbon-based organic solvents and ketone-based solvents, exhibits high solubility in ester solvents and alcohol solvents, and has studied the blending components and balance of resin and volatile solvent components Is found. As a result of intensive studies to solve the above-mentioned problems, the present inventor made a specific blend with hydroxypropylcellulose and polyurethane as essential components in the binder resin of the laminate ink composition for soft packaging. While satisfying the basic characteristics of this ink, the inventors found that fluidity, adhesion to a printing medium, and suitability for boil and retort were improved even in an ester solvent / alcohol solvent mixed type. In addition, the hydrocarbon solvent of the present invention means an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, or an alicyclic hydrocarbon solvent.

  That is, the present invention provides a laminating ink composition for soft packaging comprising a colorant, a solvent, and a binder resin as main components, and hydroxypropylcellulose and polyurethane as the binder resin.

  According to the present invention, an organic solvent such as an aromatic hydrocarbon and a ketone solvent are not used, and the ester solvent and the alcohol solvent alone have good solubility in the solvent, and the fluidity. Thus, a laminate ink composition for soft packaging having excellent adhesion to a printing medium and suitability for boil and retort is obtained.

  The present invention relates to a laminate ink composition for soft packaging having a colorant, a solvent, and a binder resin as main components, wherein the binder resin contains hydroxypropyl cellulose and polyurethane. Offer things.

  The polyurethane resin used in the laminate ink composition for soft packaging of the present invention is not particularly limited as long as it dissolves only in an ester solvent and an alcohol solvent without using a hydrocarbon or a ketone. Among these, as an alcohol component of a polyurethane resin, a polyurethane resin obtained by reacting an aliphatic polyol, polyalkylene glycol, or an aliphatic polyester having a hydroxyl group at a terminal with a polyisocyanate includes an ester solvent and an alcohol. A solvent alone is preferable because it can be easily dissolved. Furthermore, the alcohol component is preferably an aliphatic polyester having a hydroxyl group at the terminal.

  Examples of the aliphatic polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2methyl-1,3-propanediol, 2ethyl-2butyl-1,3propanediol, 1, 3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol Saturated or unsaturated such as triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaesitol Low molecular polyol etc. And the like.

  Examples of the polyalkylene glycols include polymers or copolymer polyether polyols such as methylene oxide, ethylene oxide, and tetrahydrofuran.

Examples of the aliphatic polyester having a hydroxyl group at the terminal include linear (linear) resins containing an excess of hydroxyl groups obtained by reacting glycol with dibasic acid or a derivative thereof as essential components. Of course, in place of the dibasic acid, an ester-forming derivative such as a dibasic acid anhydride or a dibasic acid lower alkyl ester is used, and not only in a polycondensation reaction, but also in an addition reaction or a transesterification reaction, a polyester resin Can also be obtained.

  Examples of the polyester resin include aliphatics such as ethylene glycol, propylene glycol, butanediol, pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, hexanediol, heptanediol, decanediol, and cyclohexanedimethanol. Fat obtained by reacting glycol with an aliphatic dibasic acid such as succinic acid, adipic acid, sebacic acid, suberic acid fumarate, azelaic acid, 1,10-decamethylenedicarboxylic acid, cyclohexanedicarboxylic acid as an essential raw material component As an essential raw material component, an aliphatic polyester resin, an aliphatic glycol such as ethylene glycol, propylene glycol, or butanediol, and an aromatic dibasic acid such as terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid are used as an essential raw material component. And aromatic polyester resin obtained by.

  Among these, aliphatic polyester resins obtained by reacting aliphatic glycol and aliphatic dibasic acid as essential components are particularly preferable.

  Polyisocyanates are not particularly limited, and examples thereof include 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, and 4,4′-dibenzyl isocyanate. Aromatic diisocyanates such as dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, Methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexa Aliphatic diisocyanates such as 1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate (Including cycloaliphatic diisocyanates). Of these, aliphatic diisocyanates are preferred because the resulting polyurethane resin is less susceptible to yellowing over time and has good solubility in ester solvents and alcohol solvents.

  The polyurethane resin may be a polyurethane polyurea resin obtained by reacting an alcohol component and a polyisocyanate component at a composition ratio in which an isocyanate group becomes excessive, and then extending a chain with a chain extender.

  Examples of the chain extender include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4′-diamine and the like, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine. 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, di- Amines having a hydroxyl group in the molecule such as 2-hydroxypropylethylenediamine can also be used. These chain extenders can be used alone or in admixture of two or more.

  Furthermore, a monovalent active hydrogen compound can also be used as a terminal blocking agent for the purpose of stopping the reaction. Examples of such a compound include alcohols such as propyl alcohol. Moreover, dialkylamines, such as di-n-butylamine, amino acids, such as ethanol, glycine, and L-alanine, can be used as a reaction terminator. These end blockers can be used alone or in admixture of two or more.

  The polyurethane resin preferably has a number average molecular weight of 10,000 or more because the resulting ink composition has good blocking resistance, laminate strength and chemical resistance, and the resulting ink composition does not have a too high viscosity and has a predetermined viscosity. The number average molecular weight is preferably 100,000 or less because the printing density is easily obtained.

  The content of the polyurethane resin used in the laminating ink composition for soft packaging of the present invention in the ink is 3% by weight or more based on the total weight of the ink from the viewpoint of ensuring sufficient adhesion of the ink to the printing medium. From the viewpoint of ink viscosity and work efficiency during ink production and printing, it is preferably 20% by weight or less, and more preferably in the range of 6 to 15% by weight.

  The hydroxypropyl cellulose used in the present invention preferably has a hydroxypropoxyl group content of 53 to 75% by weight, for example, Nippon Soda Co., Ltd. (HPC-SSL, HPC-SL, HPC-L), etc. Can be mentioned.

  The molecular weight of hydroxypropylcellulose is preferably about 40,000 to 210,000. If the hydroxypropyl cellulose satisfies the above-mentioned requirements with such a molecular weight, good properties as an ink can be provided. If the molecular weight is small, the fluidity and the plate fogging tendency tend to decrease, and if the molecular weight is too large, the viscosity of the ink increases and the fluidity tends to decrease. The addition amount with respect to the total amount of the ink is 0.1 to 10% by weight, preferably 0.5 to 3.0% by weight. When the addition amount is large, fluidity, adhesion to the printing medium, and boil resistance tend to decrease. Conversely, when the addition amount is small, plate fogging and transferability during printing decrease.

  The weight ratio of hydroxypropyl cellulose / polyurethane in the laminate ink composition for soft packaging of the present invention is preferably in the range of 5/95 to 60/40. When the hydroxypropylcellulose / polyurethane ratio is small, the plate fog / transferability tends to be low, and when it is large, the fluidity, adhesion to the printing medium, and boil resistance tend to be low.

  The polyurethane resin used in the laminating ink composition for soft packaging of the present invention is prepared by reacting a prepolymer of a terminal isocyanate group obtained by reacting, for example, a polyol with a diisocyanate compound in an excess ratio of an isocyanate group. Medium, that is, a two-stage method of reacting with a chain extender and / or a terminal blocker in a solvent usually used as a solvent for non-toluene gravure ink, or polypropylene glycol and a combination polyol, diisocyanate compound, chain extender And / or is prepared by a one-step process in which the endblocker is reacted at once in a suitable solvent of the above. Among these methods, it is preferable to use a two-stage method in order to obtain a uniform polyurethane resin. Further, when the polyurethane resin is produced by a two-stage method, the total (equivalent ratio) of the active hydrogens of the amino groups of the chain extender and / or end-capping agent is 1 / 0.9 to 1.3. It is preferable to make it react. When the equivalent ratio of isocyanate group and active hydrogen group of amino group is less than 1 / 1.3, the chain extender and / or the end-capping agent remain unreacted, and the polyurethane resin turns yellow, Odor may be generated after printing.

  The solvent used in the laminate ink composition for soft packaging of the present invention does not contain an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent and an alicyclic hydrocarbon solvent, an alcohol solvent and an ester solvent or Contains one or more selected from the group consisting of water.

  Examples of the alcohol solvent used in the laminate ink composition for soft packaging of the present invention include aliphatic alcohols having 1 to 7 carbon atoms such as methanol, ethanol, normal propanol, isopropanol, normal butanol, isobutanol, and tertiary butanol; Examples include glycol ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol propyl ether, propylene glycol isopropyl ether, and propylene glycol monobutyl ether. Of these, alcohol solvents having 1 to 7 carbon atoms are preferable, and isopropanol, ethanol, normal propanol, and propylene glycol monomethyl ether are particularly preferable. These may be used alone or in combination of two or more.

  Examples of the ester solvent used in the laminate ink composition for soft packaging of the present invention include ester solvents such as methyl acetate, ethyl acetate, normal propyl acetate, isopropyl acetate, normal butyl acetate, and isobutyl acetate.

  In the laminate ink composition for soft packaging of the present invention, the alcohol component and / or the ester solvent as a solvent component, the content of 0.1 to 70% by weight with respect to the total amount of the ink composition, and the printability is good. Therefore, water can be more preferably contained in an amount of 0.1 to 50% by weight. In this case, the water may be added to an organic solvent to form a water-containing organic solvent, or a specific amount of water may be added separately.

Furthermore, in order to obtain heat resistance for the ink film, a resin having a urea bond such as the polyurethane resin is effective. At that time, urea bonds are bonded to each other by hydrogen bonds, so that the viscosity of the ink is increased and printability tends to be deteriorated. In order to prevent such a phenomenon, water is preferably contained in the ink composition at a content of less than 10% in order to reduce the viscosity of the resin bonded with urea bonds and hydrogen bonds. Moreover, it is also possible to reduce the used organic solvent component by addition of such water.
Furthermore, there is also a function of controlling the drying property of the ink by adding water. In particular, in the case of gravure printing, it is possible to clearly reproduce a gradation portion having a low ink transfer amount, which is a feature of the ink.

  Examples of the colorant used in the laminate ink composition for soft packaging 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.

  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.

  These organic pigments and inorganic pigments also have the effect of improving the drying properties and printing characteristics of the ink by the addition of the moisture described above.

(Normal production method)
The laminate ink composition for soft packaging of the present invention can be produced, for example, by polyurethane resin, other binder resin, coloring pigment, extender pigment, solvent, water, and, if necessary, antistatic agent or antiblocking agent. In addition, an additive such as a plasticizer, a surfactant for improving ink fluidity and dispersibility, or a resin having compatibility with a polyurethane resin is used in a range in which thickening and gelation do not occur over time, This is done by kneading using a printing ink manufacturing apparatus such as a ball mill, an attritor, a sand mill, or a paint conditioner.

  Any resin or additive compatible with the polyurethane resin can be used in combination.

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

In addition, the weight average molecular weight (Mw) described in the Example of this invention is the value measured on condition of the following using a gel permeation chromatograph (GPC).
Measuring device: HLC-8220 manufactured by Tosoh Corporation
Column: Guard column H _XL- H manufactured by Tosoh Corporation
+ Tosoh Corporation TSKgel G5000H _XL
+ Tosoh Corporation TSKgel G4000H _XL
+ Tosoh Corporation TSKgel G3000H _XL
+ Tosoh Corporation TSKgel G2000H _XL
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation SC-8010
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow rate: 1.0 ml / min Standard: Polystyrene sample: Use a 0.4% by weight tetrahydrofuran solution (100 μl) filtered through a microfilter in terms of resin solids.

(Preparation of polyurethane polyurea resin A)
In a four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube, 240 parts of polypropylene glycol having a molecular weight of 1,000, neopentyl glycol having a molecular weight of 1,000, and adipic acid 42 parts of the condensate were charged, and the temperature was raised to 50 ° C. while flowing nitrogen gas and stirring. Subsequently, 126 parts of isophorone diisocyanate was added and reacted at 90 ° C. until NCO%, which is the residual ratio of isocyanate groups, reached 5.8 to obtain a linear polyurethane prepolymer having aliphatic isocyanate groups at both ends. .
Subsequently, in a four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube, 23 parts of isophoronediamine, 14 parts of N-aminoethyl-2-ethanolamine, and dinormalbutylamine 5 parts and 1,050 parts of isopropyl alcohol were mixed and heated to 40 ° C. Next, 408 parts of the polyurethane prepolymer obtained in the previous step was charged and reacted at 40 ° C. for 4 hours to obtain a polyurethane polyurea resin solution having a solid content of 30% by weight and a weight average molecular weight (Mw) of 52,000, “Resin A”. Obtained.

(Preparation of polyurethane polyurea resin B)
Number average molecular weight obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a four-necked flask equipped with a stirrer, thermometer, Dimroth type reflux condenser, and nitrogen gas inlet tube Charge 772 parts of 2,000 polyester diols and 167.1 parts of isophorone diisocyanate, flow nitrogen gas and react at 90 ° C. until the NCO%, which is the residual ratio of isocyanate groups, reaches 3.2. , 750 parts were added to obtain a urethane prepolymer solution.
Subsequently, 583 parts of isopropyl alcohol, 54 parts of isophorone diamine, and 6.9 parts of dinormal butyl amine were mixed in a four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction pipe. The temperature was raised to 40 ° C. Next, 2689.1 parts of the polyurethane prepolymer solution obtained in the previous step was charged and reacted at 45 ° C. for 7 hours to obtain a polyurethane polyurea resin solution having a solid content of 30% by weight and a weight average molecular weight (Mw) of 48,000, “resin B "was obtained.

Examples 1 to 11 and Comparative Examples 1 to 7 will be specifically described.
(Ink preparation method)
In a 450 ml glass bottle, 200 parts of 1.5 mm glass beads are charged, and Example 1 is taken as an example. 32 parts of ethyl acetate, 20 parts of IPA, 5 parts of water, 3 HPC-L (manufactured by Nippon Soda Co., Ltd.) 10 parts of MONARCH 460 (manufactured by Cabot Specialty Chemicals, Inc.) as carbon black was added, and after dispersion for 1 hour with a paint conditioner, glass beads were filtered with a wire mesh to prepare ink. For Examples 2 to 11 and Comparative Examples 1 to 7, inks were prepared in the same procedure as in Example 1 at the blending ratios shown in Tables 1 and 2.

  The following evaluation was implemented about the ink of Examples 1-11 obtained above and the ink of Comparative Examples 1-7.

(Liquidity)
The viscosities of the inks listed in Tables 1 and 2 were measured with a B-type viscometer at 6 rpm and 60 rpm. The viscosity measured at 6 rpm was divided by the viscosity measured at 60 rpm to determine the TI value. If the TI value is less than 3.0, it can be used practically.
(Evaluation)
◯: TI value is less than 1.5 Δ: TI value is 1.5 or more and less than 3.0 ×: TI value is 3.0 or more

(Adhesion)
The inks listed in Table 1 and Table 2 were developed with a bar coater # 4 on the treated surface of a biaxially stretched polyethylene terephthalate film (E5102, 12 μm, manufactured by Toyobo Co., Ltd.) having a corona discharge treatment on one side. 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.
(Evaluation)
A: Area ratio of ink adhering to cellophane tape 0%
○: Area ratio of ink adhering to cellophane tape is less than 10% Δ: Area ratio of ink adhering to cellophane tape is less than 30% ×: Area ratio of ink adhering to cellophane tape is 30% or more XX: Adhering to cellophane tape More than 80% ink area ratio

(Plate cover)
The inks listed in Table 1 and Table 2 were diluted with ethyl acetate / IPA = 1/1, and diluted with Zaan Cup No. 3 manufactured by Kosei Co., Ltd. so that the time was 16 seconds. The adjusted ink is printed on the treated surface of a biaxially stretched polypropylene film (Pyrene P-2161 20 μm, manufactured by Toyobo Co., Ltd.) subjected to corona discharge treatment on one side using a gravure printing machine equipped with a semi-solid plate. It was. The printing speed is changed to 100 m / min, 150 m / min, and 200 m / min. The ink in the non-image area of the semi-solid plate is not scraped off, and the leaked ink is transferred to the biaxially stretched polypropylene film (plate The degree of occurrence of (fog) was visually evaluated. If the plate fog phenomenon does not occur under the printing conditions of 100 m / min, it can be determined that the level is practical. However, it is desirable that the plate fog phenomenon does not occur even at a higher printing speed.
(Evaluation)
◎: No plate fog phenomenon occurs at a printing speed of 200 m / min. ○: No plate fog phenomenon occurs at a printing speed of 150 m / min. Δ: No plate fog phenomenon occurs at a printing speed of 100 m / min. X: Printing speed of 100 m Plate fog phenomenon occurs at / min. XX: Plate fog phenomenon occurs severely at a printing speed of 100m / min.

(Metastatic)
The inks listed in Table 1 and Table 2 were diluted with ethyl acetate / IPA = 1/1, and diluted with Zahn Cup No. 3 made by Kogaisha Co., Ltd. so as to be 16 seconds. It printed on the processing surface of the biaxially-stretched polypropylene film (Toyobo Co., Ltd. pyrene P-2161 20micrometer) which gave the corona discharge process to one side using the gravure printing machine which attached the gradation plate. The printing speed was changed to 50 m / min and 80 m / min, and the presence or absence of missing ink (scratch) in the highlight portion (cell volume: 5%, 10%) of the gradation plate was visually evaluated. Although it can be determined that it is a practical level if no blurring occurs in the 10% cell volume under printing conditions of a printing speed of 80 m / min or more, it is desirable that no blurring occurs even at a lower printing speed and at a lower cell volume%.
(Evaluation)
◎: No blurring at a printing speed of 50 m / min. ○: No blurring at a printing speed of 80 m / min. Δ: Scratching occurs at a printing speed of 80 m / min and a cell volume of 5%, but a cell volume of 10%.
No blurring occurred: Scratch can be remarkably confirmed even at a printing speed of 80 m / min and a cell volume of 10%.

(Boil aptitude)
The inks listed in Table 1 and Table 2 were diluted with ethyl acetate / IPA = 1/1, and diluted with Zahn Cup No. 3 made by Kogaisha Co., Ltd. so as to be 16 seconds. The adjusted ink is printed on the treated surface of a biaxially stretched polyethylene terephthalate film (E5102, 12 μm, manufactured by Toyobo Co., Ltd.) subjected to corona discharge treatment on one side using a gravure printing machine equipped with a solid plate (Helio 175 line). Went. On the ink surface of the obtained printed matter, a laminating adhesive in which 5 parts of Dick Dry LX-401, 5 parts of SP-60, and 20 parts of ethyl acetate were mixed was applied with a bar coater # 12, and one side was used with a precision laminator. Were laminated together with a L-LDPE film (TUX-HC 60 μm, manufactured by Mitsui Chemicals Tosero Co., Ltd.) subjected to corona discharge treatment to obtain a laminate. The laminate was aged at 40 ° C. for 48 hours.
The laminate, which is the laminate after aging, is three-side sealed with a heat sealer under the conditions of 180 ° C., 1 second, and 0.1 MPa to make a pouch. Add salad oil / meat sauce / vinegar = 1/1/1 in it. And the upper part is sealed. Using a boil tester, boil treatment was performed at 98 ° C. for 30 minutes, 60 minutes and 90 minutes, and the appearance was visually evaluated. If the appearance is not abnormal after boiling for 30 minutes, it can be judged as a practical level, but it is desirable to be able to withstand a longer processing time.
(Evaluation)
◎: No abnormality in the appearance even after 90 minutes of boil treatment ○: No abnormality in the appearance after 60 minutes of boil treatment △: No abnormality in the appearance after 30 minutes of boil treatment XX: Lami floating can be confirmed partially XX: Lami Frequent floats or broken bags

The raw materials in the table are as follows.
MONARCH 460 (manufactured by Cabot Specialty Chemicals, Inc.): carbon black, particle size 27 nm, BET specific surface area 84 m ² / g
HPC-L (Nippon Soda Co., Ltd.): Hydroxypropylcellulose Weight average molecular weight (Mw) 200,000, Viscosity 6-10 (mPa · s 20 ° C / 2% aqueous solution)
HPC-SL (manufactured by Nippon Soda Co., Ltd.): Hydroxypropylcellulose Weight average molecular weight (Mw) 120,000, Viscosity 3 to 5.9 (mPa · s 20 ° C./2% aqueous solution)
HPC-SSL (manufactured by Nippon Soda Co., Ltd.): hydroxypropylcellulose weight average molecular weight (Mw) 50,000, viscosity 2 to 2.9 (mPa · s 20 ° C./2% aqueous solution)
NC (L1 / 8) (manufactured by Asahi Kasei Corporation): Nitrified cotton CAP-482-0.5 (manufactured by EASTMAN CHEMICAL): cellulose acetate propionate CAB-381-0.1 (manufactured by EASTMAN CHEMICAL): cellulose acetate butyro Nate S-REC B BL-1 (manufactured by Sekisui Chemical Co., Ltd.) polyvinyl butyral resin: glass transition point 68 ° C., hydroxyl group 36 (mol%)
Solvein TA5R (manufactured by Nissin Chemical Industry Co., Ltd.) Vinyl chloride vinyl acetate copolymer resin: number average molecular weight 28,000, glass transition point 78 ° C., K value = 41
Resin composition; vinyl chloride / vinyl acetate / vinyl alcohol = 88/1/11 (weight ratio)

  From the above results, the laminate ink composition for soft packaging of the present invention has excellent printability and boil resistance without using an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, or an alicyclic hydrocarbon solvent. Can be maintained.

  The laminating ink composition for soft packaging of the present invention is a dearomatic hydrocarbon solvent, dealiphatic hydrocarbon solvent and delipidated cyclic hydrocarbon solvent that are environmentally and hygienically considered in gravure printing. Yes, it is an ink composition with excellent printability due to a resin composition that has good solubility in ester solvents and alcohol solvents, and is widely used in flexible packaging applications for food packaging materials and industrial products such as sanitary, cosmetics, and electronic parts. obtain.

Claims (5)

A laminate ink composition for soft packaging, comprising a colorant, a solvent, and a binder resin as main components, wherein the binder resin contains hydroxypropyl cellulose and polyurethane. The content of the hydroxypropyl cellulose is 0.1 to 10% by weight in the laminate ink composition for soft packaging, and the content of the polyurethane is 3 to 20% by weight in the laminate ink composition for soft packaging, The laminate ink composition for soft packaging according to claim 1, wherein the ratio of hydroxypropylcellulose / polyurethane is in the range of 5/95 to 60/40 (weight ratio). The laminate ink composition for soft packaging according to claim 1, wherein the solvent does not contain a hydrocarbon solvent and contains an alcohol solvent and / or an ester solvent.   Furthermore, the laminate ink composition for soft packaging of Claim 1, 2 or 3 which water contains in the range of 0.1 to 70 weight% with respect to the ink composition whole quantity. The laminated body obtained by printing the laminated ink composition for soft packaging of said 1-4.