JP2976291B2 - Binder for printing ink and printing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a binder for printing ink. More specifically, the present invention relates to a binder for a printing ink suitable for printing a plastic film having excellent re-solubility and color tone reproducibility of the ink.

[0002]

2. Description of the Related Art Conventionally, solvents such as toluene, methyl ethyl ketone (MEK) and ethyl acetate have been mixed and used as solvents for printing inks for plastic films. Of these, toluene is inexpensive and has a relatively high boiling point, so the drying of the ink on the gravure plate is suppressed during printing, and the ink in the cells of the gravure plate that has not transferred to the film remains in the ink pan. In contact with the ink,
It is a suitable solvent to prevent plate clogging of cells by sufficiently re-dissolving, and has been used as a main solvent of the printing ink. As a binder having good resolubility in a printing ink using a solvent containing these toluenes, 3-Binder is used.
A polyurethane resin using methylpentane adipate diol (for example, JP-A-63-16065) is known.

[0003]

However, in recent years,
The revision of the Occupational Safety and Health Law has strengthened regulations on the environmental concentration of toluene, which has necessitated an improvement in the printing work environment.Moreover, toluene has a relatively high boiling point and tends to remain in printed matter in large quantities. After the enforcement of the law, it became necessary to reduce the residual solvent, and the demand for a solvent-based printing ink containing no toluene increased. With conventional printing inks using polyester-based polyurethane resin as a binder only with a solvent such as MEK and ethyl acetate excluding toluene, the ink remaining in the gravure plate cells is reduced due to the rapid drying of the solvent. There is a problem that the ink is dried before coming into contact with the ink, does not sufficiently re-dissolve, and causes clogging of the plate, so that printing cannot be performed with a plate having a small depth. In addition, when the above-mentioned polyurethane resin, which had an appropriate ink resolubility in a conventional toluene-containing solvent system, was changed to MEK or an ethyl acetate-based solvent, these solvents have a higher dissolving power of the polyurethane resin than toluene. Because of the large size, when different types of color inks are overprinted, there is a problem that the previously printed ink film dissolves in the subsequently printed ink film, causing color transfer and poor color tone reproduction.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies with the aim of solving the above-mentioned problems, and as a result, a polyester polyol using two kinds of diols in a specific ratio has been used as a polymer polyol component of a polyurethane resin. By using the same, even in an ink solvent containing no toluene, it has been found that a binder for a printing ink that is excellent in re-solubility and color tone reproducibility of the ink and suitable for printing various plastic films can be obtained. Reached.

That is, the present invention relates to a polymer diol (A)
And at least 50% by weight of (A) in a binder for a printing ink comprising a polyurethane resin having a total amine value of 0.2 to 20, derived from an organic diisocyanate (B) and an aliphatic diamine (C). Has 2 carbon atoms
Polyester diol (A1) comprising a mixed diol (a) having a molar ratio of linear diol (a1) of from 6 to 6: branched diol (a2) having 3 to 6 carbon atoms of 2: 8 to 8: 2 and dicarboxylic acid (b). A) a solvent-based printing ink binder containing no toluene; and a toluene-free solvent-based printing ink for a plastic film, wherein the binder is the main binder; and a polyester film, a nylon film, and a surface. A plastic film obtained by applying the printing ink to a plastic film selected from a treated or untreated polypropylene film, a polyethylene film, a polyvinyl acetal film, an acetate film, a polyvinyl chloride film and a film obtained by subjecting these films to aluminum evaporation. is there.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the linear diol (a1) having 2 to 6 carbon atoms constituting the mixed diol (a) as a raw material of the polyester diol (A1) is ethylene glycol, 1,3- Propylene glycol,
Examples thereof include 1,4-butylene glycol, 1,5-pentylene glycol, 1,6-hexamethylene glycol, diethylene glycol, and a mixture of two or more thereof. Preferred among these is 1,4-butylene glycol.

The branched diol having 3 to 6 carbon atoms (a2) includes 1,2-propylene glycol, 1- or 2-propylene glycol.
-Methyl-1,3-butylene glycol, 1- or 2-methyl-1,4-pentylene glycol, 1,2-
Or 2,3-dimethyl-, neopentyl glycol, 1-, 2- or 3-methyl-1,5-pentylene glycol, 1,2-, 1,3-, 2,3- or 1,4-dimethyl Butylene glycol and their 2
Mixtures of more than one type are included. Of these, particularly preferred is neopentyl glycol.

The ratio of (a1) to (a2) in (a) is a molar ratio, wherein (a1) :( a2) is usually 2: 8 to 8: 2,
Preferably 3: 7 to 7: 3, particularly preferably 4: 6 to
6: 4. If the ratio of (a2) is less than 20 mol%, the resolubility is poor, and if it exceeds 80 mol%, color transfer occurs, resulting in poor color tone reproducibility.

The dicarboxylic acid (b) constituting the polyester diol (A1) is an aliphatic dicarboxylic acid having 4 to 12 carbon atoms [adipic acid, succinic acid, sebacic acid, azelaic acid, fumaric acid, maleic acid, etc.] , Aromatic dicarboxylic acids [terephthalic acid, isophthalic acid, etc.]
And a mixture of two or more of these. Of these, preferred are adipic acid, sebacic acid,
Azelaic, terephthalic and isophthalic acids, particularly preferred are adipic and sebacic acids. The (b) also includes an ester-forming derivative such as an anhydride of the dicarboxylic acid and an esterified product of a lower alcohol having 1 to 5 carbon atoms.

The number average molecular weight of the polyester diol (A1) is usually from 700 to 4,000, preferably from 1,0 to 4,000.
00 to 3,500, particularly preferably 1,200 to 3,0
00. If it is less than 700, the obtained polyurethane resin is hard and brittle, and has high resolubility,
If it exceeds 0, the polyurethane resin will be soft and the adhesiveness will be poor, and the color tone reproducibility will be poor due to excessive re-dissolution in the solvent.

In the present invention, the polyester diol (A
1) can be obtained by a method similar to a conventionally known method for producing an ester. In the esterification reaction, (b) is replaced with (a1)
And (b2) react simultaneously, but (b1)
Alternatively, after reacting either one of (a2), the other may be successively reacted.

In the polyurethane resin of the present invention, other polyester diols and polyether diols can be used in combination with the polymer diol (A1) if necessary. In this case, the content of (A1) in (A) is usually at least 50% by weight, preferably at least 70% by weight, particularly preferably at least 80% by weight. If the content of (A1) is less than 50% by weight, it is difficult to achieve both re-dissolvability of the ink and color tone reproducibility.

The other polyester diols which can be used in combination with (A1) include a number average molecular weight of 700 to 4,000.
Known polyester diols (polyethylene adipate diol, polybutylene adipate diol, polyethylene butylene adipate diol, polyneopenthylene adipate diol, poly-3-methylpentylene adipate diol, polycaprolactone diol, polyvalerolactone diol, polyhexamethylene carbonate diol Etc.).

The other polyether diol which can be used in combination with (A1) includes a number average molecular weight of 700 to 4,000.
[Polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol, and the like].

The organic diisocyanate (B) used in the present invention has a carbon number (excluding the carbon number in the NCO group)
4 to 15 alicyclic diisocyanates [isophorone diisocyanate (IPDI), dicyclohexylmethane-
4,4'-diisocyanate (hydrogenated MDI), 1,4-
Cyclohexane diisocyanate (CHI), methylcyclohexylene diisocyanate (hydrogenated TDI), etc.]; carbon number (excluding carbon number in NCO group) 2 to 12
Aliphatic diisocyanates [tetramethylene diisocyanate, hexamethylene diisocyanate (HDI),
Dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, etc.]; 8 to 12 carbon atoms (excluding the number of carbon atoms in the NCO group) araliphatic diisocyanate [xylylene diisocyanate (XDI), α, α , Α ', α'-Tetramethylxylylene diisocyanate (TMXDI)
Etc.]; modified products of these organic diisocyanates (for example, modified products of uretdione, isocyanurate, buret, carbodiimide, etc.) and mixtures of two or more of these. Preferred of these are:
Alicyclic diisocyanates, particularly preferred are I
PDI, hydrogenated MDI and mixtures thereof.

As the aliphatic diamine (C) constituting the polyurethane resin in the present invention, an aliphatic diamine or a derivative thereof (ethylenediamine, propylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, N-hydroxyethylethylenediamine, N, N'-dihydroxyethylethylenediamine and the like; alicyclic diamine (isophoronediamine, 4,
4'-diaminodicyclohexylmethane, isopropylidenedicyclohexyl-4,4'-diamine, etc.) and mixtures of two or more thereof. Among these, preferred are N-hydroxyethylethylenediamine, isophoronediamine and 4,4'-diaminodicyclohexylmethane.

In the polyurethane resin of the present invention, a low molecular weight diol having a number average molecular weight of less than 500 together with a high molecular weight diol (A) [alkylene oxide adducts of glycols and bisphenols exemplified in the above (a1) and (a2)] , Dimethylolpropionic acid, etc.]. When used in combination, the amount of the low molecular weight diol is usually at most 30% by weight, preferably at most 20% by weight, based on (A). If it exceeds 30% by weight, the resolubility decreases.

If necessary, a terminating agent can be used. Examples of the terminator include monoalcohols (methanol, propanol, butanol, 2-ethylhexanol and the like), monoamines [mono- or dialkylamines having 2 to 8 carbon atoms (butylamine, dibutylamine and the like), mono- and dialkylamines having 2 to 6 carbon atoms. Dialkanolamine (monoethanolamine, diethanolamine, propanolamine, etc.)]. Preferred among these are monoamines.

The polyurethane resin of the present invention has a primary or secondary amino group in the molecular chain, and has an amine value of usually 0.2 to 20, preferably 0.5 to 15, and particularly preferably 1 to 10. is there. By setting the amine value within the above range, it becomes possible to impart good adhesion to a surface-treated (corona-treated or the like) polypropylene film.

In producing the polyurethane resin (B)
The equivalent ratio of the isocyanate group of (A) to the active hydrogen-containing group of (A) is usually 1: (0.4 to 0.92), preferably 1:
(0.5-0.8), and the equivalent ratio of the isocyanate group of (B) to the active hydrogen-containing group of (C) is usually 1: (0.8
To 0.1), preferably 1: (0.7 to 0.25). The equivalent ratio of the isocyanate group of (B) and the active hydrogen-containing group of (A) and (C) is usually 1:
(1.4 to 1.02), preferably 1: (1.2 to 1.0)
1.05).

The method for producing the polyurethane resin is not particularly limited, and is a one-shot method in which the components are reacted at once or a multi-stage method in which the components are reacted stepwise [eg, by reacting (B) with a part of the active hydrogen compound. After the isocyanate group-terminated prepolymer is formed, and then the remaining active hydrogen compound is added thereto and further reacted to produce the isocyanate group-terminated prepolymer. The multi-stage method is preferred in that the introduction of the group is easy.

The production of the polyurethane resin is usually 20 to 1
The reaction is carried out at a temperature of 40 ° C., preferably 40 to 120 ° C. (However, when a polyamine is reacted, it is usually 100 ° C.)
Hereinafter, it is preferably 0 to 80 ° C. ).

In the above reaction, in order to promote the reaction, a catalyst used in a usual urethane reaction [amine catalyst (triethylamine, N-ethylmorpholine, triethylenediamine, etc.), a tin catalyst (dibutyltin dilaurate, dioctyl) may be used, if necessary. Tin dilaurate,
Tin octylate), a titanium-based catalyst (such as tetrabutyl titanate)] and the like. The amount of the catalyst used is usually 0.1% by weight or less based on the polyurethane resin.

The above reaction may be carried out in an organic solvent, or the organic solvent may be added during or after the reaction.
Solvents that can be used include ester solvents (ethyl acetate, butyl acetate, ethyl cellosolve acetate, etc.),
Ketone solvents (acetone, MEK, methyl isobutyl ketone, etc.), ether solvents (dioxane, tetrahydrofuran, propylene glycol monomethyl ether, etc.), hydrocarbon solvents (n-hexane, n-heptane, cyclohexane, etc.), alcohol solvents Solvents (ethanol, methanol, isopropyl alcohol (IP
A), n-propyl alcohol, butanol, etc.). Among them, preferred are ethyl acetate, butyl acetate, propylene glycol monomethyl ether, MEK, IPA and n-propyl alcohol, and particularly preferred are ethyl acetate, MEK and IPA.

GPC of polyurethane resin in the present invention
Number average molecular weight is usually 5,000 to 100,00
0, preferably 7,000 to 50,000, particularly preferably 10,000 to 30,000. By setting the number average molecular weight within the above range, a binder having a good balance between the blocking resistance of the ink coating film and the re-solubility of the ink when the ink is formed can be obtained.

The binder for printing ink of the present invention is used as a solution (varnish) obtained by dissolving the polyurethane resin in the solvent exemplified above. The resin concentration of the solution is usually 10 to 60% by weight, preferably 20 to 50% by weight. The viscosity is usually 50-100,000 cP / 25.
° C, preferably 100 to 10,000 cP / 25 ° C.

The printing ink of the present invention contains the above-mentioned binder and pigment as main components. The pigment is not particularly limited, and inorganic and organic pigments used in ordinary printing inks can be used.

If necessary, additives such as other resins, solvents and pigment dispersants commonly used in printing inks can be added. As the other resins, for example, polyamide resin, nitrocellulose, acrylic resin,
Examples include vinyl acetate resin, vinyl chloride resin, styrene maleic acid copolymer resin, chlorinated polyolefin, epoxy resin, and rosin resin. The addition amount of these other resins is usually 30% by weight or less in the ink, preferably 2% by weight.
0% by weight or less.

The method of mixing the components is not particularly limited, and a printing ink can be produced by using an ordinary ink production apparatus such as a three-roll mill, ball mill, sand grinder mill and the like.

An example of the formulation of the printing ink of the present invention is as follows (% indicates% by weight). Normal (preferably) The binder (solid content) of the present invention 5 to 40% (10 to 30%) Pigment 5 to 40% (10 to 30%) Other resins 0 to 30% (0 to 20%) ) Solvent (including solvent in resin component) 30-80% (40-70%)

The printing ink comprising the binder of the present invention may be used as a one-part printing ink, but may also be used as a two-part printing ink in combination with, for example, a polyisocyanate-based curing agent. As the polyisocyanate-based curing agent in this case, for example, an adduct from 1 mol of trimethylolpropane and 3 mol of 1,6-hexamethylene diisoisocyanate, tolylene diisocyanate or isophorone diisocyanate;
Trimers containing isocyanurate groups synthesized by cyclotrimerization of isocyanate groups of hexamethylene diisoisocyanate or isophorone diisocyanate; partial burette derived from 1 mol of water and 3 mol of 1,6-hexamethylene diisoisocyanate Reactants and mixtures of two or more of these are preferred. When used as a two-part printing ink, the amount of the polyisocyanate-based curing agent to be added is usually 0.5 to 10% by weight based on the ink.

The printing method using the printing ink of the present invention comprises:
It may be the same as the case of the special gravure printing ink used for printing a conventional plastic film.

Examples of the plastic film to which the printing ink of the present invention is applied include polyester film, nylon film, surface-treated or untreated polypropylene film, polyethylene film, polyvinyl acetal film, acetate film, polyvinyl chloride film, and these films. And a film on which aluminum is deposited.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the following, "parts" indicates parts by weight and "%" indicates% by weight.

Example 1 A four-necked flask equipped with a thermometer and a stirrer was charged with poly-
Butylene neopentylene adipate diol (1,4-
The molar ratio of butanediol to neopentyl glycol is 5
0/50, number average molecular weight 2010) 200 parts and IP
After 33.3 parts of DI was charged and reacted at 120 ° C. for 5 hours with stirring, the mixture was cooled to 40 ° C., and 350 parts of MEK was added and dissolved to obtain a MEK solution of an NCO-terminated polyurethane resin having an NCO content of 0.72%. IPA2 is added to the obtained MEK solution.
10 parts, 6.4 parts of isophoronediamine (IPDA) and 0.37 part of monoethanolamine were added to carry out chain extension, and the resin concentration was 30.0%, the viscosity was 1200 cP / 25 ° C.,
A polyurethane resin solution having a total amine value (converted to the concentration in the solid content) of 2.1 was obtained. The number average molecular weight (hereinafter the same) of the resin measured by gel permeation chromatography (GPC) was 20,000.

Using the obtained polyurethane resin solution as a binder, a printing ink was prepared according to the following formulation. [Preparation of white ink] Polyurethane resin solution 100 parts Pigment (rutile type titanium oxide) 90 parts IPA 30 parts MEK 40 parts Ethyl acetate 40 parts Ceramic balls 150 parts [Preparation of blue ink] Polyurethane resin solution 100 parts Pigment (β-phthalocyanine) Blue) 30 parts IPA 30 parts MEK 70 parts Ethyl acetate 70 parts Ceramic balls 150 parts The above-mentioned raw material mixture is put into a steel can with an inner volume of 500 ml, and a paint conditioner (manufactured by Red Devil Co., Ltd.)
For 1 hour to obtain a printing ink [1].

Example 2 In the same manner as in Example 1, poly-butylene neopentene adipate diol (molar ratio of 1,4-butanediol to neopentyl glycol was 50/50, number average molecular weight 2
500) 250 parts, IPDI 37.7 parts, MEK432
From these parts, a MEK solution of an NCO-terminated polyurethane resin having an NCO content of 0.82% was obtained. IP to the obtained MEK solution
A260 parts, 8.5 parts of IPDA and 0.6 parts of monoethanolamine, a resin concentration of 30.0% and a viscosity of 106
0 cP / 25 ° C, total amine value (converted to concentration in solids)
A polyurethane resin solution of 0.7 was obtained. The number average molecular weight of this resin was 15,000. A printing ink [2] was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Example 3 In the same manner as in Example 1, poly-butylene neopentyl adipate diol (molar ratio of 1,4-butanediol to neopentyl glycol was 50/50, number average molecular weight was 1)
500) 150 parts, IPDI 28.9 parts, MEK268
A MEK solution of an NCO-terminated polyurethane resin having an NCO content of 0.56% was obtained from the parts. IP to the obtained MEK solution
A160 parts, 8.5 parts of IPDA and 0.06 parts of monoethanolamine, a resin concentration of 30.0% and a viscosity of 10
00cP / 25 ° C, total amine value (converted to concentration in solids)
A polyurethane resin solution of 0.7 was obtained. The number average molecular weight of this resin was 19,000. A printing ink [3] was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Comparative Example 1 In the same manner as in Example 1, 200 parts of poly-3-methylpentylene adipate diol (number average molecular weight 2000), I
A MEK solution of an NCO-terminated polyurethane resin having an NCO content of 0.70% was obtained from 33.3 parts of PDI and 350 parts of MEK. 210 parts of IPA and IPD were added to the obtained MEK solution.
A6.5 parts and 0.4 parts of monoethanolamine, resin concentration 30.0%, viscosity 1000 cP / 25 ° C.
A polyurethane resin solution having a total amine value (converted to the concentration in solid content) of 0.7 was obtained. The number average molecular weight of this resin is 20,0
00. A printing ink [4] was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Comparative Example 2 In the same manner as in Example 1, 200 parts of poly-neopenthylene adipate diol (number average molecular weight 2000), IPD
NCO content 0.7 from 33.3 parts of ME and 350 parts of MEK
A 0% MEK solution of the NCO terminated polyurethane resin was obtained. 210 parts of IPA and IPDA were added to the obtained MEK solution.
From 6.5 parts and 0.4 parts of monoethanolamine,
A polyurethane resin solution having a resin concentration of 30.0%, a viscosity of 860 cP / 25 ° C., and a total amine value (converted to the concentration in solid content) of 0.7 was obtained. The number average molecular weight of this resin was 19,000. A printing ink [5] was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Comparative Example 3 In the same manner as in Example 1, 200 parts of poly-butylene adipate diol (number average molecular weight: 2000), IPDI3
NCO content 0.70% from 3.3 parts, MEK350 parts
To obtain an NCO-terminated polyurethane resin MEK solution. The resulting MEK solution was prepared by adding 210 parts of IPA, 6.5 parts of IPDA, and 0.4 part of monoethanolamine to a resin concentration of 30.0%, a viscosity of 1300 cP / 25 ° C., and a total amine value of 0. Thus, a polyurethane resin solution of No. 7 was obtained. The number average molecular weight of this resin was 20,000. A printing ink [6] was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Performance Test Examples Using the printing inks [1] to [6] obtained in Examples 1 to 3 and Comparative Examples 1 to 3, the following performance tests were performed.
Table 1 shows the results. (1) Resolubility A white ink was applied to a glass plate with a solid content of 2 to 3 μm using a bar coater, left at room temperature for 10 seconds to make the ink surface semi-dry, and then dried with a solvent (MEK / acetic acid). (Ethyl / IPA = 1/1/1), and the resolubility of the ink film was observed. Evaluation criteria ○: Semi-dried coating film is redissolved ×: Semi-dried coating film is not dissolved and remains on glass plate (2) Plate clogging Gravure printing tester (TS-1 type printing machine; manufactured by Higashiya Iron Works) Then, using a gravure plate having a depth of 35 μm, 30 m /
After printing 100 m of the white ink on the OPP film at a speed of 1 minute, the excess ink adhering to the gravure plate was washed off lightly with the mixed solvent, and the clogging state of the cells was observed. (3) Color transfer Blue ink is applied to the surface-treated polypropylene film (OPP) with a bar coater so as to have a solid content of 2 to 3 μm, and dried at 60 ° C. for 10 seconds. Was applied with a bar coater to a thickness of 2 to 3 μm, and the appearance of the base blue ink being eluted and mixed with the white ink was observed. (4) Cellotape Adhesiveness A white ink is applied to a surface-treated polypropylene film (OPP), a surface-treated polyester film (PET), and a surface-treated nylon film by a bar coater so as to have a solid content of a thickness of 2 to 3 μm. After drying for 1 minute, cellophane tape (made by Nichiban, 12 mm width) was attached to the coated surface, and the state of the coated surface when one end of the cellophane was rapidly peeled off in a direction perpendicular to the coated surface was observed. (5) Blocking resistance The coated test piece (P
The coated surface of the ET was overlaid on the non-coated surface, and a load of 1.0 kgf / cm ² × was applied at a temperature of 40 ° C. and a humidity of 60% RH, and peeled off after 24 hours to observe the state of the surface. (6) Lamination test A white ink was applied to a surface-treated polyester film (PET) with a bar coater so as to have a solid content of 2 to 3 μm, and dried at 60 ° C. for 1 minute. Urethane adhesive [Eunoflex J-3 (manufactured by Sanyo Chemical Industries, Ltd.)]
Is adjusted to a solid content concentration of 30% with ethyl acetate] using a bar coater so that the solid content has a thickness of 2 to 3 μm, and surface-treated polypropylene film (CPP)
And laminated at 40 ° C. for 1 day to form a laminate film. A test piece with a width of 15 mm was collected from this,
The T peel strength (g) was measured by an autograph.

[0043]

[Table 1]

[0044]

The binder of the present invention provides a printing ink having excellent resolubility and color tone reproducibility even in an ink solvent containing no toluene. The printing ink using the binder of the present invention is excellent in resolubility and color tone reproducibility even in an ink solvent not containing toluene, compared with a printing ink using a conventional polyester-based polyurethane resin, and is a gravure plate at the time of printing. The ink remaining in the cell is redissolved, the plate is not clogged, and when overprinting is performed, the previous ink does not melt and transfer color. Because of the above effects, the binder of the present invention,
Particularly, it is suitable as a binder for special gravure ink for various plastic films (polyester film, nylon film, polypropylene film, cellophane film, etc.). Further, the binder of the present invention is excellent not only for the above-mentioned applications but also as a binder for flexographic printing inks, a binder for paints, an adhesive, and a coating agent for paper and the like because of its excellent adhesiveness to various substrates. .

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09D 11/00-11/20

Claims (4)

(57) [Claims] 1. A printing ink comprising a polyurethane resin having a total amine value of 0.2 to 20, derived from a polymer diol (A), an organic diisocyanate (B), and an aliphatic diamine (C). In the binder, (A)
Is mixed diol (a) having a molar ratio of 2: 8 to 8: 2 of linear diol (a1) having 2 to 6 carbon atoms: branched diol (a2) having 3 to 6 carbon atoms and dicarboxylic acid. A solvent-free printing ink binder containing no toluene, which is a polyester diol (A1) with an acid (b). 2. The printing ink binder according to claim 1, wherein (a1) is 1,4-butylene glycol and (a2) is neopentyl glycol. 3. A toluene-free solvent-based printing ink for a plastic film, comprising the binder according to claim 1 as a main binder. 4. Polyester film, nylon film, surface treated or untreated polypropylene film,
A plastic film obtained by applying the printing ink according to claim 3 to a plastic film selected from a polyethylene film, a polyvinyl acetal film, an acetate film, a polyvinyl chloride film, and a film obtained by subjecting these films to aluminum evaporation.