JP2019048997A - Binder for printing inks, printing ink composition for packaging laminates, and printed material - Google Patents

Abstract

To provide a binder for printing ink for obtaining an ink having excellent printability, laminate strength, boiling suitability, and retort suitability without requiring a ketone-based organic solvent or aromatic organic solvent.SOLUTION: Disclosed is a binder for printing inks, which contains a polyurethane resin, and other resins. The polyurethane resin is a polymer that contains (A) a polyol, (B) dimethylolpropionic acid, and the like. The polyol (A) contains a polyester polyol having a number average molecular weight of 1,000-6,000. The content of the dimethylolpropionic acid (B) is 0.01-5 mass% relative to the mass of the polyurethane resin. The other resins are selected from a polyurethane resin other than the polyurethane resin, a polyamide, a nitrocellulose, a poly (meth) acrylate, a polyvinyl chloride, a polyvinyl chloride vinyl acetate copolymer, a rosin-based resin, and a ketone resin.SELECTED DRAWING: None

Description

  The present invention relates to a binder for printing ink, a printing ink composition for packaging laminate, and a printed matter.

  In recent years, plastic films have come to be used in various fields as packaging materials. Printing on such plastic films is carried out by gravure printing or flexo printing. And, with the diversification of packaging substrates, the performances required for printing inks and coatings used for decoration or surface protection are becoming increasingly sophisticated.

  For example, printing inks for plastic films need to have excellent printability, adhesion, blocking resistance, gloss, etc. for a wide variety of films. Furthermore, in the field of food packaging containers, hygienically laminated packaging containers are used so that the ink does not directly touch the contents.

  In general, as laminating, the following two methods are used: printing ink using various plastic films as a printing base, and forming molten polyolefin etc. on the surface (printed surface) of the formed printing film via an anchor coating agent There are an extrusion laminating method of laminating and a dry laminating method of laminating a plastic film on the printing surface through an adhesive.

  The laminating ink to be used in the laminating method should be well adhered to printing substrates such as various plastic films, and be excellent in adhesion to the plastic film to be laminated, printability, and laminating strength. Furthermore, in order to sterilize the contents, all laminated packaging containers are boiled in hot water or boiled if retort is applied, the laminate will not float and wrinkle during processing. Aptitude and retort aptitude are required.

  Most of the above ink performance often depends mainly on the performance of the binder resin. Therefore, various binder resins are used depending on the required performance. Generally, polyurethane resin is used as binder resin of ink for lamination (refer to patent documents 1-3).

JP, 2010-270215, A JP, 2010-270216, A Patent No. 4882206

  Generally, as a binder resin for laminating ink, a polyurethane resin in which the concentration of urethane bond in the molecule is as high as possible is used. However, when the urethane bond concentration is high, the boil aptitude and retort aptitude of the ink are likely to be poor. In addition, the solubility in solvents such as methyl ethyl ketone, ethyl acetate and isopropyl alcohol decreases, and when these solvents are used, streaks are caused by the phenomenon that solid matter of the ink accumulates in the plate, which is said to be plate clogging. There is a problem (deterioration in printability) that printing defects occur in some parts.

  When using an aromatic organic solvent such as toluene, the polyurethane resin skeleton is hardened to improve the blocking resistance, and chlorinated polypropylene (PP) is added to make it suitable for boiling, retort, laminating strength, printability, An ink having good adhesion and blocking resistance can be obtained. However, from the viewpoint of working environment etc., the use of aromatic organic solvents or organic solvents which do not contain ketone organic solvents such as methyl ethyl ketone has been promoted (such as non-toluene conversion). Also, conventional inks containing organic solvents free of aromatic organic solvents and polyurethane resins have had difficulty meeting the needs of a wide variety of films.

  In one aspect, the object of the present invention is to provide a printing ink for obtaining an ink having excellent printability, laminate strength, boilability, and retortability without the need of a ketone-based organic solvent or an aromatic-based organic solvent. It is providing a binder. Another object of the present invention is to provide a printing ink composition for packaging and laminating using such a printing ink binder and a printed material obtained therefrom.

  As a result of intensive studies, the inventors of the present invention have found that polyurethane resins containing dimethylol propionic acid have excellent printability, even when ketone solvents or aromatic solvents are not used. It has been found to be effective to obtain printing inks having laminate strength, boiling and retortability. The present invention has been completed based on such findings.

  One aspect of the present invention relates to a binder for printing ink containing a polyurethane resin as a main component. The polyurethane resin is a polymer comprising (A) a polyol, (B) dimethylol propionic acid, (C) a diisocyanate compound, and (D) a chain extender. This polyurethane resin is obtained by reacting at least (A) a polyol, (B) dimethylol propionic acid, (C) a diisocyanate compound, and (D) a chain extender. (A) The polyol contains a polyester polyol having a number average molecular weight of 1000 to 6000. The content of (B) dimethylol propionic acid in the polyurethane resin is 0.01 to 5% by mass with respect to the mass of the polyurethane resin.

  When the binder contains a polyurethane resin containing dimethylol propionic acid, the printability of the printing ink is improved. In addition, when the content of dimethylol propionic acid is within the above range, the laminate strength, the boiling aptitude, the retort aptitude, the printing aptitude, etc. are improved.

  (A) The polyol may contain a polyether polyol (polyethers) having a number average molecular weight of 200 to 4,000. The polyether polyol contained in the (A) polyol may be one or more polyether polyols selected from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene ether glycol. These particular polyether polyols can contribute to further improvement of printability.

  If necessary, in addition to the polyurethane resin, a resin as shown below may be used as an accessory component. Examples thereof include polyurethane resins other than those described above, polyamide, nitrocellulose, poly (meth) acrylic acid ester, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, rosin resin, and ketone resin.

  In another aspect, the present invention relates to a printing ink composition for packaging and laminating comprising the above-mentioned binder for printing ink, a colorant and an organic solvent as components.

  The organic solvent in the printing ink composition for package lamination may not be substantially free of any of an aromatic organic solvent or a ketone organic solvent. The above-mentioned binder for printing ink is particularly suitable for a packaging laminate ink composition which does not contain an aromatic organic solvent or a ketone organic solvent. However, it is also possible to use the said binder for the ink composition containing an aromatic type organic solvent or a ketone type organic solvent, and the outstanding characteristic may be exhibited also in that case.

  Yet another aspect of the present invention relates to a printed matter formed by printing the above-described ink composition for package lamination. This printed matter has a printing film containing a binder for printing ink and a colorant.

  The present invention can provide a binder for a printing ink for obtaining an ink excellent in printability, laminate strength, boiling ability and retortability. Since this binder is excellent in solubility in a solvent, it prevents plate clogging and hardly causes printing defects in the image area.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  The binder for printing ink which concerns on one Embodiment is a binder (binder resin) which contains a polyurethane resin as a main component. Usually, 50 to 100% by mass of the entire binder is composed of a polyurethane resin.

  The polyurethane resin in the binder may be a polymer obtained by reacting at least (A) a polyol, (B) dimethylol propionic acid, (C) diisocyanate compound, and (D) a chain extender. . The polyurethane resin is derived from each of a polyol, dimethylol propionic acid, a diisocyanate compound, and a chain extender. The content of (B) dimethylol propionic acid (content of the structural unit derived from dimethylol propionic acid) in the polyurethane resin may be 0.01 to 5% by mass with respect to the mass of the polyurethane resin.

  (A) Polyol contains polyester polyol. The polyester polyol is a polyester containing a diol, a dicarboxylic acid and the like, and has a hydroxyl group at the end.

  The number average molecular weight of the polyester polyol may be 1000 to 6000. In the present specification, the number average molecular weight of each material may be a value converted by standard polystyrene, which is measured by gel permeation chromatography (GPC).

  Examples of the diol constituting the polyester polyol include ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, triethylene glycol, 1- or 2-methyl-1,3-butylene glycol, 1- or 2-methyl-1,3-butylene glycol, 1- or 2-methyl-1,4-pentylene glycol, 2,4-diethyl-1,5-pentanediol, tripropylene glycol, 1,2- Propylene glycol, 1,3-butanediol, 1-, 2- or 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, bisphenol A ethylene oxide, propylene oxide, ethylene Alkylene such as propylene oxide Oxide adducts, neopentyl glycol, butyl ethyl propanediol. Among these, 3-methyl-1,5-pentanediol and / or neopentyl glycol may be particularly selected. By selecting 3-methyl-1,5-pentanediol and / or neopentyl glycol, the effects according to the present invention can be more significantly exhibited.

  The polyester polyol may further contain a polyfunctional polyol. Examples of polyfunctional polyols include glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaerythritol. Be

  Examples of the dicarboxylic acid constituting the polyester polyol include adipic acid, succinic acid, sebacic acid, azelaic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, and a combination of two or more of these. Among these, adipic acid and / or sebacic acid may be particularly selected. By particularly selecting adipic acid and / or sebacic acid, the effects of the present invention can be more significantly exhibited.

  The polyester polyol may contain, in addition to the dicarboxylic acid, or in place of the dicarboxylic acid, an anhydride of the dicarboxylic acid and / or an esterified product of the lower alcohol having 1 to 5 carbon atoms of the dicarboxylic acid.

  The polyester polyol in the present embodiment can be obtained by the same method as the conventional polyester manufacturing method. For example, a polyester polyol can be obtained by dehydration condensation of a diol and a dicarboxylic acid or an acid anhydride.

  The (A) polyol may contain polyether polyols (polyethers) having a number average molecular weight of 200 to 4,000. Examples of polyether polyols include polyoxyalkylene glycols such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene ether glycol (PTMG), and alkylene oxide adducts of bisphenol A. The alkylene oxide added to bisphenol A may be, for example, ethylene oxide, propylene oxide, or a combination thereof.

  When the polyether polyol contained in the (A) polyol is one or more selected from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene ether glycol, the printability can be further improved. From the same viewpoint, the number average molecular weight of these glycols may be 600 to 3,000.

  The polyurethane resin is obtained by reacting (B) dimethylol propionic acid (DMPA) with another monomer. This polyurethane resin is sometimes referred to herein as "DMPA-modified polyurethane resin".

  The content of dimethylol propionic acid (B) may be 0.01 to 5% by mass with respect to the mass of the polyurethane resin. (B) If the content of DMPA is 0.01% by mass or more, the pigment dispersibility of the printing ink is good. When the content is 5% by mass or less, the film (printed film) does not become excessively hard, and it is easy to obtain good laminate strength, boil aptitude and retort aptitude. That is, when the content of DMPA is in the range of 0.01 to 5% by mass, effects such as improvement in laminate strength, boiling aptitude, retort aptitude, and printing aptitude can be obtained. From the same viewpoint, the content of DMPA may be 0.05 to 4% by mass, or 0.1 to 3% by mass.

  The (C) diisocyanate compound constituting the polyurethane resin is a compound having two isocyanate groups, and may be any of aromatic, aliphatic or alicyclic diisocyanates.

  Representative examples of isocyanate compounds include 1,5-naphthyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 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 2,4,4-Trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate Of xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, m-tetramethyl xylylene diisocyanate, and dimer acid There may be mentioned dimeric isocyanates in which carboxyl groups have been converted to isocyanate groups. These diisocyanate compounds may be used alone or in combination of two or more. Of these, cycloaliphatic diisocyanates, in particular isophorone diisocyanate (IPDI) may be selected. By using the alicyclic diisocyanate, the effects of the present invention can be more significantly exhibited.

  The (D) chain extender constituting the polyurethane resin can be optionally selected from those commonly used as a chain extender for polyurethane resins, and may be, for example, a polyamine or a glycol. Examples of chain extenders include ethylene diamine, propylene diamine, hexamethylene diamine, triethylene tetramine, diethylene triamine, isophorone diamine, dicyclohexylmethane-4,4'-diamine, and dimer diamine. Examples of other chain extenders include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2- The diamine which has a hydroxyl group in molecule | numerators, such as a hydroxypropyl ethylene diamine, the glycol already illustrated as a polyol which comprises polyester polyol, and glycols other than that are mentioned. One of these chain extenders may be used alone, or two or more thereof may be used in combination. Among these, isophorone diamine may be selected. By selecting isophorone diamine, the effect according to the present invention can be more significantly exhibited.

  The chain extender may be a diol having a tertiary amine structure such as methyldiethanolamine, methyldiisopropanolamine, phenyldiisopropanolamine, 4-methylphenyldiisopropanolamine, 4-methylphenyldiethanolamine, or a combination of two or more of these. It may be.

  When synthesizing a polyurethane resin, a chain length terminator can also be used as needed. Examples of such chain terminators include monoalcohols and monoamines. Examples of monoalcohols include methanol, propanol, butanol and 2-ethylhexanol. Examples of monoamines include C2-C8 mono- or dialkylamines (butylamine, dibutylamine etc.) and C2-C6 mono- or dialkanolamines (monoethanolamine, diethanolamine, propanolamine etc.).

  The content of each of (A) polyol, (C) diisocyanate compound, and (D) chain extender in the polyurethane resin can be optionally adjusted.

  The polyurethane resin is produced, for example, by the reaction of a raw material mixture containing (A) polyol, (B) dimethylol propionic acid and (C) diisocyanate compound to form a urethane prepolymer having a urethane bond and an isocyanate group, It can synthesize | combine by the method including producing | generating polyurethane resin by reaction of a polymer and (D) chain extender. The conditions for synthesis, etc. can be appropriately set according to a conventional method in the synthesis of polyurethane resin.

  The ink composition which concerns on one Embodiment contains the said binder for printing inks, a coloring agent, and the organic solvent. The ink composition can be a packaging laminate ink composition used to form a printed film of a packaging container produced by a laminating method. The content of the binder (the concentration of resin solid content) in the ink composition is usually about 3 to 50% by mass with respect to the mass of the ink composition.

  The colorant in the ink composition can be appropriately selected from those commonly used as a colorant for printing ink. Examples of colorants include pigments such as cyanine blue. The content of the colorant in the ink composition is usually about 1 to 60% by mass with respect to the mass of the ink composition.

  The organic solvent constituting the ink composition may be, for example, ethyl acetate, isopropyl alcohol or a combination thereof. The organic solvent may be substantially free of either an aromatic organic solvent or a ketone organic solvent. More specifically, the total content of the aromatic organic solvent and the ketone organic solvent in the organic solvent may be 0 to 1% by mass with respect to the mass of the organic solvent.

  The printed matter according to one embodiment has a substrate and a printing film formed on the substrate. A printing film contains the said binder for printing inks, and a coloring agent. The printed matter may be a packaging container (particularly, a food packaging container) further having a plastic film laminated on the substrate while covering the printing film. The printed film can be formed by a method including printing the above ink composition on a substrate and removing the organic solvent from the printed ink composition. The method of printing is not particularly limited, and may be gravure printing or flexographic printing, for example. The thickness of the printing film is usually about 0.1 to 30 μm. The base material constituting the printed matter, the plastic film to be laminated, the adhesive used for lamination, and the like are not particularly limited, and can be appropriately selected from commonly used materials.

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments. Hereinafter, "part" represents "part by mass" and "%" represents "% by mass".

Synthesis Example 1 (Synthesis of Polyurethane Resin A)
In a round bottom flask equipped with a stirrer, a thermometer and a nitrogen gas inlet tube, a polyester polyol having a number average molecular weight of 3000 (3-methyl-1,5-pentanediol manufactured by Hitachi Chemical Co., Ltd.) as component (A) 300 parts of adipate, 1.5 parts of dimethylol propionic acid (DMPA, Wako Pure Chemical Industries, Ltd.) as component (B), and isophorone diisocyanate (IPDI, Wako Pure Chemical Industries, Ltd.) as component (C) ) 49.4 parts. These were reacted at 105 ° C. for 6 hours under a nitrogen stream to form a prepolymer having an isocyanate group content of 2.66%. Thereto, 234 parts of ethyl acetate (Wako Pure Chemical Industries, Ltd.) was added to obtain a uniform urethane prepolymer solution. Subsequently, 20.1 parts of isophorone diamine (IPDA, Wako Pure Chemical Industries, Ltd.) as component (D), and 1.7 parts of di-n-butylamine (DBA, Wako Pure Chemical Industries, Ltd.) 585 parts of the urethane prepolymer solution was added to a mixture of 375 parts of ethyl acetate (Wako Pure Chemical Industries, Ltd.) and 261 parts of isopropyl alcohol (Wako Pure Chemical Industries, Ltd.) as an organic solvent. The resulting solution was heated to 60 ° C., and reaction for 3 hours gave a solution of a polyurethane resin (DMPA-modified polyurethane resin) containing dimethylol propionic acid. Regarding a solution of this DMPA-modified polyurethane resin (hereinafter referred to as "polyurethane resin solution A"), the concentration (NV) of resin solid content (polyurethane resin) is 30%, viscosity is 500 mPa · s (25 ° C), and amine value is 0 It was .5 mg KOH / g. The content of DMPA in the DMPA-modified polyurethane resin was 0.4% as calculated from the amounts of raw materials charged.

(Composition examples 2 to 12)
Polyurethane resin solutions B to L were obtained in the same manner as in Synthesis Example 1 using the raw materials shown in Tables 1 and 2.

1. Preparation of Ink Composition (Examples 1 to 10 and Comparative Examples 1 to 3)
Ink Composition for Color Pigment Dispersion Evaluation In Example 1, a nitrocellulose solution (solvent) was used with respect to 28 parts of the polyurethane resin solution of Synthesis Examples 1 to 12, 10 parts of cyanine blue, and 52 parts of mixed solvent (ethyl acetate / isopropyl alcohol). : Mixed solvent, concentration: 30%) 3.5 parts in Examples 2 to 10 and Comparative Examples 1 to 3 10 parts of a solution of vinyl chloride vinyl acetate copolymer resin (solvent: ethyl acetate, concentration: 15%) Mixed.
Each obtained mixture was dispersed for 3 hours using a pigment disperser (paint shaker). Thereafter, using the mixed solvent, the viscosity of the obtained dispersion is determined using Zahn cup no. The number of seconds measured in 3 was adjusted to 15 seconds to obtain an ink composition for color pigment dispersibility evaluation.
The mixing ratio in the mixed solvent used for preparation of the ink composition was set to ethyl acetate / isopropyl alcohol = 7/3 (mass ratio).

Other Ink Composition for Evaluation The solution of nitrocellulose in Example 1 with respect to 35 parts of the solution of polyurethane resin of Synthesis Examples 1 to 12, 35 parts of titanium white, and 20 parts of mixed solvent (ethyl acetate / isopropyl alcohol) (Solvent: mixed solvent, concentration: 30%) 3.5 parts in Examples 2 to 10 and Comparative Examples 1 to 3 Solution of vinyl chloride vinyl acetate copolymer resin (solvent: ethyl acetate, concentration: 15%) 10 The parts were mixed.
Each obtained mixture was dispersed for 1 hour using a pigment disperser (paint shaker). The viscosity of the obtained dispersion was measured using a mixed solvent, using a Zahn cup No. 1 solution. It adjusted so that the number of seconds measured by 3 might be 15 seconds, and obtained the ink composition for evaluation of following (2)-(6).
The mixing ratio in the mixed solvent used for preparation of the ink composition was set to ethyl acetate / isopropyl alcohol = 7/3 (mass ratio).

2. Evaluation (1) Color pigment dispersibility The above-mentioned ink composition was printed on a polyethylene terephthalate film (hereinafter abbreviated as "PET film") to prepare a printing film having a coating film as a printing film. The state of the coating film (printing film) of the obtained printing film was visually observed, and the color pigment dispersibility was determined on the basis of the following criteria. The uneven color in the coating film means that the dispersibility of the pigment is poor.
"A": There is no color unevenness in the coating.
"B": part of the coating film has uneven color.
"C": color unevenness occurs in the coating film.

(2) Adhesiveness The above-mentioned ink composition containing titanium white was printed on a PET film or nylon film (hereinafter abbreviated as "NY film") to produce a print film having a coating film as a print film. . After the printed film was allowed to stand for 24 hours, a cellophane tape was applied to the coating, which was rapidly peeled off. The state of the coating film at this time was observed, and the adhesion of the coating film was evaluated based on the following criteria.
"A": 80% or more of the coating film remains on the film.
"B": 50 to 80% of the coating film remains on the film.
"C": 50% or less of the coating film remains on the film.

(3) Printability The above ink composition containing titanium white was printed on a PET film using a small gravure printing tester to form a print pattern (printed film). Thereafter, the condition of the printing pattern, that is, the condition of the doctor cutting of the plate and the lack of the printing pattern related to the cell clogging were visually observed, and the printability was determined according to the following criteria.
"A": printability is good.
"B": printability is insufficient.
"C": the printability is extremely poor.

(4) Dry (DL) Lamination Strength The above ink composition containing titanium white was printed on a PET film or NY film to obtain a printed matter having a coating film as a printing film. A non-oriented polypropylene film (CPP film) was laminated by a dry laminating machine while sandwiching a urethane adhesive on the coating film. The resulting laminate was aged at 40 ° C. for 2 days (the third day after lamination), and then cut into a width of 15 mm, and the 180 ° peel strength was measured.

(5) Boil aptitude test The above-mentioned ink composition containing titanium white was printed on a PET film or a NY film to obtain a printed matter having a coating film as a printing film. After applying an isocyanate type adhesive to the coating film, a 60 μm polyethylene film was laminated by a dry laminating machine to obtain a laminate. The laminate was used to make a bag, into which a water / oil mixture was added to seal the bag. Next, the bag was heated in hot water of 95 ° C. for 30 minutes, and the floating state of the laminate was observed to evaluate the boil aptitude based on the following criteria.
"A": The laminate was completely free from lifting.
"B": Partial lifting occurred in the laminate.
"C": A lift occurred on the entire surface of the laminate.

(6) Retort Suitability Test A coated film of the above ink composition containing titanium white was printed on a PET film or a NY film to obtain a printed matter. After applying an isocyanate type adhesive to the coating film, a 60 μm non-oriented polypropylene (CPP) film was laminated by a dry laminating machine to obtain a laminate. The laminate was used to make a bag, into which a water / oil mixture was added to seal the bag. Next, the bag was heated in pressurized hot water at 120 ° C. for 30 minutes, and the floating state of the laminate was observed to evaluate retort suitability based on the following criteria.
"A": There was no float on the laminate.
"B": Partial lifting occurred in the laminate.
"C": A lift occurred on the entire surface of the laminate.

  The evaluation result "AB" in the table means that the evaluation was intermediate between A and B. As shown in Tables 3 and 4, the ink compositions of Comparative Examples 1 to 3 containing a polyurethane resin whose content of dimethylol propionic acid is not in the range of 0.01 to 5% by mass as a binder have color pigment dispersibility. It did not show sufficient properties in any of adhesion, printability, boiling and retortability.

  On the other hand, the ink compositions of Examples 1 to 10, which contain as a binder a polyurethane resin having a content of dimethylol propionic acid in the range of 0.01 to 5% by mass, have color pigment dispersibility, adhesiveness, and printability. It can be seen that the laminate strength, the boil aptitude, and the retort aptitude are all excellent.

  Therefore, the ink composition containing the binder for printing ink of the present invention can have good color pigment dispersibility without using an aromatic organic solvent or a ketone organic solvent. In addition, the ink composition containing the binder for printing ink of the present invention is excellent in adhesiveness (lamination strength) and printability, and is also excellent in boiling aptitude and retort aptitude, so a binder for printing ink used in food packaging containers etc. It is extremely useful as

Claims (8)

A binder for printing ink comprising a polyurethane resin and another resin, wherein
The polyurethane resin is a polymer comprising (A) a polyol, (B) dimethylol propionic acid, (C) a diisocyanate compound, and (D) a chain extender.
The (A) polyol contains a polyester polyol having a number average molecular weight of 1000 to 6000,
The content of (B) dimethylol propionic acid in the polyurethane resin is 0.01 to 5% by mass with respect to the mass of the polyurethane resin,
The other resin is selected from polyurethane resins other than the polyurethane resin, polyamide, nitrocellulose, poly (meth) acrylic acid ester, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, rosin resin, and ketone resin.
Binder for printing ink.   The binder for printing inks of Claim 1 whose number average molecular weight of the said polyester polyol is 3000-6000.   The binder for printing inks of Claim 1 or 2 in which the said (A) polyol further contains the polyether polyol whose number average molecular weight is 200-4000.   The binder for printing ink according to claim 2, wherein the polyether polyol is one or more selected from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene ether glycol.   The printing ink composition for package laminations containing the binder for printing inks as described in any one of Claims 1-4, a coloring agent, and an organic solvent.   The printing ink composition for packaging laminate according to claim 5, wherein the organic solvent is substantially free of any of an aromatic organic solvent or a ketone organic solvent.   The printing ink composition for the packaging laminate according to claim 5 or 6, wherein the organic solvent comprises ethyl acetate and isopropyl alcohol.   The printed matter which has a printing film containing the binder for printing inks as described in any one of Claims 1-4, and a coloring agent.