JPH0641488A - Printing ink binder and printing ink composition - Google Patents

Abstract

PURPOSE:To provide the printing ink binder excellent in adhesion to a plastic film such as a polyester, nylon, or polyolefin film and also in processiblities in direct lamination and retorting. CONSTITUTION:The binder contains as the main component a mixture of a polyurethane resin with a urethane-modified chlorinated polypropylene obtd. by reacting a chlorinated polypropylene having, on average, 1.5-4 hydroxyl groups per molecule, a diisocyanate compd., and, if necessary, a chain extender and/or a chain stopper. The compsn. contains the mixture as the main binder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a binder for printing ink.
And a printing ink composition. More specifically, it relates to a printing ink binder and a printing ink composition which are particularly useful as a coating agent for plastic films, plastic sheets or synthetic resin molded articles.

[0002]

2. Description of the Related Art In recent years, various plastic films have been developed as a packaging material in accordance with the diversification of packaging objects and the sophistication of packaging technology, and a suitable one for the packaging object should be appropriately selected and used. Is becoming. In addition, when plastic films are used as packaging materials, they are printed for decoration or surface protection of plastic films, and the printing ink for such printing has high performance and quality for these various plastic films. Is being demanded.

In particular, for printing inks, a wide range of adhesiveness to various composite films for the purpose of making packaging containers more beautiful and sophisticated, and further, suitability for laminate processing, suitability for boil,
Various post-processing suitability such as retort suitability is required. Generally, methods such as gravure printing and flexographic printing are used for plastic films and the like, but in the case of film printing as a packaging material, most of them are winding methods, and thus the printing ink is required to have quick drying property. In addition, when used as a packaging for foods, it is particularly required that the residual solvent is small.

Further, in order to improve the performance of packaging materials, dry lamination processing after printing and extrusion lamination lamination are performed.
Processing may be applied. In particular, films such as polyester and nylon are superior in strength and airtightness to other films, and are laminated with polyethylene film or polypropylene film. In this case, urethane is used for dry lamination. An adhesive such as a system is used, and an anchor coating agent is used in the case of extrusion lamination processing. Further, an aluminum foil may be interposed in the middle so that the packaging material can be boiled or retort processed. Further, in the packaging material field in which a transparent base material is used as a base, oriented polypropylene (OPP) is used as a base material film, and an anchor coating agent is not used, and the melt is directly melted. A lamination processing method (PP direct lamination) of coating with polypropylene is also performed.

In order to carry out such post-processing, it is required that the printing ink used in the preceding step has not only the adhesiveness to various substrate films and printability but also the suitability for each post-processing. Such suitability is mainly determined by the binder used in the printing ink.

Conventionally, as a printing ink used for polyester film, a thermoplastic polyester resin is used as a binder.
When a nylon film and a polyester film are used, a two-pack type reactive ink of a polyester resin having a hydroxyl group and an isocyanate compound is used. Further, recently, printing inks having polyurethane as a binder have been widely used as those having wide suitability for base films such as nylon, polyester and the like.

On the other hand, for polyolefins subjected to PP direct lamination, a chlorinated polyolefin having a relatively low degree of chlorination such as chlorinated polypropylene is used as a binder.
Printing ink is used. However, the printing ink using the thermoplastic polyester resin not only has a limited base film, but also has insufficient drying properties and has a problem in workability such as blocking, and the two-component ink is a reactive type, so that it is a pot. The life is short, various restrictions are imposed on work, and there is an economic loss such as disposal of unused ink.
In addition, printing inks with polyurethane as a binder have excellent adhesiveness independently to polyester films and nylon films, but sufficient adhesion to polyolefin films such as polyethylene films and polypropylene films, which are general-purpose films. There is a problem that it is not strong and that the laminating processability, especially PP direct laminating is insufficient.

Printing inks containing chlorinated polyolefin as a binder show good adhesion to polyolefin films, but do not have sufficient adhesion to polyester films and nylon films, so that the base film is limited. Further, although it has PP direct laminate suitability, it has no boil suitability and retort suitability, and its use is limited. Further, the compatibility of chlorinated polyolefin and polyurethane is poor and it is difficult to use a mixture of the two.

As described above, in the conventional printing ink binder, the base material film is limited, or even if it has general versatility with respect to the base material film, the adhesiveness is insufficient, and the laminate is used. It was not sufficiently suitable for processing, boil processing, and retort processing.
Therefore, it is necessary to produce a printing ink containing a binder suitable for each base film, various laminating process, retort process, etc. each time. There was a big problem in inventory management of materials and inks.

[0010]

DISCLOSURE OF THE INVENTION The present invention has excellent adhesiveness to any of various plastic films such as polyester, nylon, polyethylene and polypropylene as a material to be printed, suitability for laminate processing, suitability for boil processing and retort. Binder for printing ink with processability
And to provide a printing ink composition.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that a chlorinated polypropylene having a hydroxyl group in the molecule is combined with a diisocyanate compound and a chain if necessary. Urethane was modified with an extender and / or a chain length terminating agent to improve compatibility with the polyurethane resin. As a result, it has been surprisingly found that by using a mixture of the urethane-modified chlorinated polypropylene and the polyurethane resin as the main component of the binder for printing ink, all the problems of the prior art can be solved.

That is, the present invention has an average of 1.5 in the molecule.
A main component is a mixture of a chlorinated polypropylene having 4 to 4 hydroxyl groups, a diisocyanate compound, and a urethane-modified chlorinated polypropylene obtained by reacting a chain extender and / or a chain length terminating agent if necessary, and a polyurethane resin. And a printing ink composition containing a mixture of the urethane-modified chlorinated polypropylene and a polyurethane resin as a main binder.

In the present invention, a mixture of a urethane-modified chlorinated polypropylene and a polyurethane resin obtained by reacting a specific chlorinated polypropylene having a hydroxyl group with a diisocyanate compound and, if necessary, a chain extender and / or a chain length terminating agent. It is mandatory to use it as the main binder.

Chlorinated polypropylene having an average of 1.5 to 4 hydroxyl groups in the molecule (hereinafter, hydroxyl group-containing chlorinated P
P) is not particularly limited in its manufacturing method,
Any chlorinated polypropylene having an average of 1.5 to 4 hydroxyl groups in the molecule may be used. For example, commercially available chlorinated polypropylene and a compound having a hydroxyl group and a radically polymerizable double bond are known. It can be produced by reacting by the method of. Here, the chlorination degree of the raw material chlorinated polypropylene is usually 20 to 60, and particularly preferably 25 to 45. If it is less than 20, the solubility in organic solvents will decrease, and if it exceeds 60, the adhesion to polyolefins and other synthetic resins will decrease when the modified chlorinated PP component is used. Further, as the compound having a hydroxyl group and a radically polymerizable double bond, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, allyl alcohol, 1,4-
Examples include butenediol.

The number average molecular weight of the obtained hydroxyl group-containing chlorinated PP is usually 500 to 50,000, preferably 700 to 3
It is 0000. If it is less than 500, the solubility in the solvent tends to be lowered after the urethane modification, and if it exceeds 50,000, the solubility and the compatibility with the polyurethane resin after the urethane modification are poor, which is not preferable.

As the diisocyanate compound used for producing the urethane-modified chlorinated polypropylene, various known aromatic, aliphatic or alicyclic diisocyanates can be used. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate. , 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, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-
Typical examples thereof include bis (isocyanate methyl) cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate and dimer diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group. Take as an example.

As the chain extender component, various known ones can be used. For example, ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine and the like can be mentioned. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-
2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and other diamines having a hydroxyl group in the molecule, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3 -Propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4- Representative examples thereof include various well-known saturated and unsaturated low molecular weight glycols having a molecular weight of less than 400 such as butynediol and dipropylene glycol, and dimer-diamine obtained by converting a carboxyl group of dimer acid into an amino group. .

Furthermore, a chain length terminator can be used.
Examples of such chain length terminators include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol.

The method for producing the urethane-modified chlorinated polypropylene is not particularly limited, but for example, a hydroxyl group-containing chlorinated PP and a diisocyanate compound may be used in a range where the isocyanate group is equivalent to or less than the hydroxyl group of the hydroxyl group-containing chlorinated PP. And a method of reacting the hydroxyl groups of the hydroxyl group-containing chlorinated PP in excess with the isocyanate groups (preferably 3 ≧ isocyanate group (equivalent) / hydroxyl group (equivalent)> 1). In the latter case, a method of reacting a hydroxyl group-containing chlorinated PP, a diisocyanate compound and a chain extender and / or a chain terminator at once, or a method of first reacting a hydroxyl group-containing chlorinated PP and a diisocyanate compound, and then chain extension and / or A method of reacting a chain length terminating agent may be appropriately adopted. In these production methods, the solvent used is usually an aromatic solvent such as benzene, toluene, xylene, which is well known as a solvent for printing inks; methanol, ethanol, isopropanol.
Alcohol, n-butanol, and other alcohol solvents; acetone,
Examples of the solvent include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate, which can be used as a mixture.

The number average molecular weight of the urethane-modified chlorinated PP is usually in the range of 1,000 to 100,000.

The polyurethane resin which is another constituent of the present invention is not particularly limited, and various known polyurethane resins can be used as they are. As the polymer polyol component in the polyurethane resin, for example, polyether polyols such as polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc .; ethylene glycol, diethylene glycol, triethylene Glico
1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol
, Neopentyl glycol, pentandiole, 3-
Methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-butyndiole
Saturated and unsaturated known low-molecular-weight glycols such as glycol and dipropylene glycol, or alkyl glycidyl ethers such as n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and versatic acid Monocarboxylic acid glycidyl esters such as glycidyl ester, dimer diol obtained by reducing dimer acid, and adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid Polyester polyols obtained by dehydration condensation of dibasic acids such as carboxylic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid and suberic acid, or acid anhydrides or dimer acids corresponding thereto; cyclic ester compounds Polyols obtained by ring-opening polymerization of styrene; other polycarbonates Various known polymer polyols generally used in the production of polyurethane, such as topolols, polybutadiene glycols, glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A, can give.

In the case of a polymer polyol obtained from a glycol and a dibasic acid among the polymer polyol components, up to 5 mol% of the glycol is It can be replaced with various kinds of polyol. For example, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-
Butanol, sorbitol, pentaerythritol
Le etc.

The number average molecular weight of the high molecular weight polyol component is appropriately determined in consideration of the solubility, drying property, blocking resistance and the like of the obtained polyurethane, and usually 700 to 1
It is about 0000, preferably within the range of 1000 to 6000. When the number average molecular weight is less than 700, the printability tends to decrease with the decrease in solubility, and when it exceeds 10,000, the drying property and blocking resistance tend to decrease.

As the diisocyanate compound used for producing the polyurethane resin, all of the above-mentioned compounds can be used. The above-mentioned chain extenders and chain length terminators can also be used.

As a method for producing the polyurethane resin, first, a polymer polyol component and a diisocyanate compound are reacted under the condition of excess isocyanate groups to prepare a prepolymer having an isocyanate group at the terminal of the polymer polyol. Then, a two-step method of reacting this with a chain extender and optionally a chain length terminating agent in a suitable solvent, and a polymer polyol component, a diisocyanate compound, a chain extender and optionally a chain length terminating agent in a suitable solvent Although any one-step method in which the reaction is carried out at once can be adopted, the former method is preferable for the purpose of obtaining a uniform polymer solution. In these production methods, the above-mentioned various types of solvents are applicable, and these can be used alone or in combination.

When the polyurethane resin is produced by the two-step method, the conditions for reacting the prepolymer with the chain extender and, if necessary, the chain length terminating agent are not particularly limited, but they are present at the end of the prepolymer. When the free isocyanate group is 1 equivalent, the total equivalent of active hydrogen capable of reacting with the isocyanate group in the chain extender is 0.5 to 2.
The amount is preferably in the range of 0 equivalents, and particularly preferably in the range of 0.5 to 1.3 equivalents when the active hydrogen-containing group is an amino group. When the amount of active hydrogen is less than 0.5 equivalent, the drying property, blocking resistance and film strength are not sufficient, and when the amount of active hydrogen is more than 2.0 equivalents, the chain extender is unreacted. It may remain as it is and is not preferable. The number average molecular weight of such a polyurethane resin is the drying property of the obtained printing ink, blocking resistance, film strength,
It is appropriately determined in consideration of oil resistance, viscosity, etc., but usually 5
The range of 000 to 100,000 is preferable.

In the present invention, the use ratio of the urethane-modified chlorinated polypropylene and the polyurethane resin is in the order of 5/95 to 60/40, preferably 10/90.
It is set within the range of 50/50. When the content of the urethane-modified chlorinated polypropylene is less than 5% by weight, the suitability for direct laminating decreases, and when it exceeds 60% by weight, the adhesion to polyester, nylon and the like, the suitability for boiling and retorting deteriorate.

The resin solid content concentration of the binder resin solution of the present invention is not particularly limited, but may be appropriately determined in consideration of workability at the time of printing and the like, usually 15 to 60% by weight, and the viscosity is 50. It is practically preferable to adjust the temperature within the range of -100,000 cP / 25 ° C. Further, in the present invention, if necessary, unless the performance of the binder of the present invention is deviated, chlorinated polyolefin such as nitrified cotton, chlorinated polyethylene, chlorinated polypropylene, and chlorinated ethylene / propylene,
Resins such as chlorosulfonated polyolefin, ethylene / vinyl acetate copolymer or its chloride or chlorosulfonate, maleic acid resin, vinyl chloride / vinyl acetate copolymer and the like can be used together.

The binder of the present invention thus obtained is a colorant, a solvent, and if necessary, a surfactant for improving the ink fluidity and the ink surface film, a wax,
Ball mill, attritor,
The printing ink composition of the present invention can be produced by kneading using a conventional ink producing device such as a sand mill. The blending amount of the binder of the present invention in the printing ink composition is such that the resin solid content in the printing ink composition is 3%.
It is preferable to mix it in an amount of about 20% by weight.

[0030]

INDUSTRIAL APPLICABILITY According to the present invention, excellent adhesion to any of various plastic films such as polyester, nylon, polyethylene and polypropylene as a material to be printed, suitability for laminating and suitability for direct laminating. It is possible to provide a printing ink binder having a boil processing suitability and a retort processing suitability, and the printing ink composition.

[0031]

EXAMPLES The present invention will be described in detail below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. Parts and% are based on weight.

Production Example 1 800 parts of a 50% toluene solution of chlorinated polypropylene (number average molecular weight 3000, chlorination degree 30%) was placed in a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube. , 2-hydroxyethyl acrylate 32
Part, t-butyl peroxybenzoate 5 parts,
The reaction was carried out at 100 ° C for 4 hours. Further, 1 part of t-butyl peroxybenzoate was added every 2 hours and reacted for 4 hours to obtain a resin solution of hydroxyl group-containing chlorinated PP. Resin solid content concentration is 51%, hydroxyl value is 3 per 1 g of resin solid content.
It was 5 KOHmg.

Production Example 2 In the same reactor as in Production Example 1, 1000 parts of a 40% toluene solution of chlorinated polypropylene (number average molecular weight of 5000, chlorination degree of 40%), 21 parts of 2-hydroxypropyl acrylate and benzoyl peroxide. 3 parts were charged and reacted at 80 ° C. for 4 hours. Further, 1 part of benzoyl peroxide was added every 2 hours and reacted for 4 hours to obtain a resin solution of chlorinated PP containing hydroxyl group. Resin solid content concentration is 41%, hydroxyl value is 21 KO per 1 g of resin solid content.
It was Hmg.

Production Example 3 A reactor similar to that of Production Example 1 was charged with 1961 parts of the hydroxyl group-containing chlorinated PP obtained in Production Example 1 and 125 parts of isophorone diisocyanate (NCO / OH = 1.8), and 100 ° C. under a nitrogen stream. Was reacted for 6 hours to obtain a prepolymer having a free isocyanate content of 1.00%. Then, 32.2 parts of isophoronediamine, 13.8 parts of di-n-butylamine and 165 parts of isopropyl alcohol were added, and the mixture was reacted under stirring at 50 ° C. for 3 hours to give a resin solid content concentration of 51.
%, A urethane-modified chlorinated polypropylene resin solution A having a number average molecular weight of 20,000 was obtained.

Production Example 4 A reactor similar to that of Production Example 1 was charged with 2439 parts of the hydroxyl group-containing chlorinated PP obtained in Production Example 2 and 83 parts of isophorone diisocyanate (NCO / OH = 2.0), and the mixture was heated to 100 ° C. under a nitrogen stream. And reacted for 6 hours at a free isocyanate content of 0.
61% prepolymer was obtained. Then 33.1 parts of isophorone diamine, 2.1 parts of di-n-butylamine and 238 parts of isopropyl alcohol are added and 5 parts are added with stirring.
The reaction was carried out at 0 ° C. for 3 hours to obtain a urethane-modified chlorinated polypropylene resin solution B having a resin solid content concentration of 40% and a number average molecular weight of 40,000.

Preparation Example 5 A reaction apparatus similar to Preparation Example 1 was charged with 1961 parts of the chlorinated PP containing hydroxyl group obtained in Preparation Example 1, 50 parts of 1,6-hexanediol and 245 parts of isophorone diisocyanate (NCO / OH = 1.5). ) Under a nitrogen stream at 100 ° C. for 6 hours to obtain a prepolymer having a free isocyanate content of 1.30%. Next, 51.4 parts of isophoronediamine, 10.5 parts of di-n-butylamine and 293 parts of isopropyl alcohol were added and reacted at 50 ° C. for 3 hours with stirring to give a resin solid content concentration of 52% and a number average molecular weight of 3000.
Urethane-modified chlorinated polypropylene resin solution C which is 0
Got

Production Example 6 A reaction apparatus similar to that of Production Example 1 was charged with 2439 parts of the chlorinated PP containing hydroxyl group obtained in Production Example 2 and 33.2 parts of isophorone diisocyanate (NCO / OH = 0.8), and the mixture was heated to 100 in a nitrogen stream. React at 10 ℃ for 10 hours, the resin solids concentration is 42
%, A urethane-modified chlorinated polypropylene resin solution D having a number average molecular weight of 20,000 was obtained.

Production Example 7 In the same reactor as in Production Example 1, 1000 parts of polyester diol having an average molecular weight of 2000 obtained from adipic acid and 1,6-hexanediol and 222 parts of isophorone diisocyanate (NCO) were used. /OH=2.0) and put it under nitrogen stream 1
The reaction was carried out at 00 ° C for 6 hours to give a free isocyanate content of 3.4.
After producing 3% of prepolymer, 815 parts of methyl ethyl ketone was added to obtain a uniform solution of urethane prepolymer. Then 74.8 parts of isophoronediamine, di-n
-Butylamine 15.2 parts, toluene 1093 parts, methyl ethyl ketone 497 parts and isopropyl alcohol 656 parts were added and reacted at 50 ° C for 3 hours with stirring,
A polyurethane resin solution E having a resin solid content concentration of 30% and a number average molecular weight of 22,000 was obtained.

Production Example 8 A reactor similar to that of Production Example 1 was charged with 1000 parts of polycaprolactone diol having a number average molecular weight of 2000 and 200 parts of isophorone diisocyanate, and the mixture was heated to 100 in a nitrogen stream.
The reaction was carried out at ℃ for 6 hours, the free isocyanate content 2.63
% Of prepolymer, 800 parts of methyl ethyl ketone was added to obtain a uniform solution of urethane prepolymer. Then, 63.0 parts of isophoronediamine, di-n-
Butylamine 5.7 parts, toluene 800 parts, methyl ethyl ketone 360 parts and isopropyl alcohol 980
20 parts by weight of the urethane prepolymer solution
00 parts was added, and the mixture was reacted under stirring at 50 ° C. for 3 hours to obtain a polyurethane resin solution F having a resin solid content concentration of 30% and a number average molecular weight of 22,000.

Examples 1 to 4 and Comparative Examples 1 to 2 As shown in Table 1 below, a predetermined amount of urethane-modified chlorinated polypropylene resin solution and polyurethane resin solution were used, and toluene was further added to prepare a binder having a nonvolatile content of 30%. Then
The ink was prepared as described below.

[0041]

(Preparation of printing ink) Titanium white (rutile type) 30 parts Binder resin solution shown in Table 1 40 parts Toluene 15 parts Isopropyl alcohol 15 parts Mixtures of composition were kneaded with a paint shaker to obtain white. A printing ink was prepared. Mixture 1 obtained
To 00 parts, 35 parts of toluene and 15 parts of isopropyl alcohol were added to adjust the viscosity, and 6-point white printing ink as shown in Table 1 was prepared.

The obtained 6 points of white printing ink were applied to the plate depth 3
By a simple gravure printing machine equipped with 0 μm gravure plate, the discharge treated surface of corona discharge treated polypropylene film (OPP) with a thickness of 15 μm, one side of polyethylene terephthalate film (PET) with a thickness of 11 μm, and corona with a thickness of 15 μm Printing was performed on the discharge-treated surface of the discharge-treated nylon film (NY) and dried at 40 to 50 ° C to obtain a printed film.

Adhesiveness After leaving the above printed matter for 1 day, cellophane tape was attached to the printed surface, and the appearance of the printed film when it was rapidly peeled off was observed and evaluated. The evaluation results are shown in Table 2. ⊚--No peeling was observed. O ----- More than 80% of the printed film remained on the film. Δ --- 50 to 80% of the printed film remained on the film. X --- 50% or less of the printed film remained on the film.

Extrusion Laminate Strength For each of the above-mentioned printed matter, OPP is imine type, PET, N
With respect to Y, an isocyanate-based anchor coating agent was used, molten polyethylene was laminated by an extrusion laminator, and after 3 days, the sample was cut into a width of 15 mm and the T-type peel strength was measured. The evaluation results are shown in Table 2.

PP Direct Laminate Strength With respect to each OPP printed matter described above, a molten polypropylene was directly laminated by an extrusion laminator, and two days later, the peel strength was measured by the same method as described above. The evaluation results are shown in Table 2.

[0047]

[Table 2]

Claims (5)

[Claims] 1. A urethane modification obtained by reacting a chlorinated polypropylene having an average of 1.5 to 4 hydroxyl groups in the molecule, a diisocyanate compound, and, if necessary, a chain extender and / or a chain length terminating agent. A binder for a printing ink, which contains a mixture of chlorinated polypropylene and a polyurethane resin as a main component. 2. The charging weight ratio of urethane-modified chlorinated polypropylene and polyurethane resin is 5 / 95-60 in order.
The binder for printing ink according to claim 1, which is / 40. 3. The printing ink binder according to claim 1, wherein the urethane-modified chlorinated polypropylene has a number average molecular weight of 1,000 to 100,000. 4. A printing ink composition for plastics containing as a main binder a mixture comprising the urethane-modified chlorinated polypropylene according to any one of claims 1 to 3 and a polyurethane resin. 5. The method according to claim 4, which is applied to a plastic substrate.
The printing ink composition described.