JP2001233929A - Polyurethane resin for printing ink, binder for printing ink and printing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing ink composition achieving both resistance to a plate-fill-in phenomenon and adhesive properties. SOLUTION: In a polyurethane resin for a printing ink comprising (a) a polymer polyol, (b) a diisocyanate compound, (c) a chain-extending agent and (d) a chain-terminating agent, a monoamine compound having a specific structure is employed as the chain-terminating agent (d). A binder for a printing ink comprises the polyurethane resin. The printing ink comprises at least 90 wt.%, based on the total solvent component in the printing ink, of at least one solvent selected from the group consisting of ketone solvents, ester solvents and alcohol solvents, and the binder for a printing ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyurethane resin for printing ink, a binder for printing ink, and a printing ink.

[0002]

2. Description of the Related Art In recent years, various plastic films have been developed and used as packaging materials with the diversification of packaging objects and the advancement of packaging technology. In order to print on these various plastic films, printing inks are required to have unprecedentedly high performance and quality. Among them, polyurethane resins are often used as printing ink resins because they are tough and easy to control various physical properties.

However, since the printing ink containing a polyurethane resin as a main component has poor solubility in a solvent, a portion where the ink is dried and deposited occurs at the image portion of the plate, and particularly a shallow portion of the plate is clogged. There is a major drawback that the phenomenon, that is, the "plate jam phenomenon" is likely to occur. In particular, in non-toluene-type inks which do not contain an aromatic solvent such as toluene due to environmental problems and contain a ketone solvent or an ester solvent as a main component, the evaporation speed of the solvent is reduced.
This "plate jam phenomenon" tends to appear remarkably because the speed is high.

[0004] In order to solve the "plate jam phenomenon", methods using a low molecular weight polyurethane resin or using a surfactant together have been tried. However, printed matter obtained using an ink using a low molecular weight polyurethane resin or an ink using a surfactant in combination has a drawback that the adhesiveness of the printing ink is inferior. As described above, there has been no technology that achieves both the “plate jam phenomenon” and the “adhesiveness”.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a problem which could not be solved by the prior art, namely, a polyurethane suitable for providing a printing ink composition having both "plate jam phenomenon" and "adhesion". We conducted intensive research on resins. as a result,
By using a specific polyurethane resin as a resin for printing ink, the above problems were completely solved. The present invention has been completed based on such new findings.

[0006]

That is, the present invention provides:
Polyurethane resins for printing inks comprising (a) a high molecular weight polyol, (b) a diisocyanate compound, (c) a chain extender and (d) a chain terminator. Equation (1):

[0007]

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(Wherein, R is a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, X is a hydrogen atom, a hydroxyethyl group,
A polyurethane resin for a printing ink, characterized by using a monoamine compound represented by a saturated or unsaturated hydrocarbon group having 1 to 18 carbon atoms; a binder for a printing ink containing the polyurethane resin; a ketone solvent A printing ink comprising at least 90% by weight of at least one solvent selected from the group consisting of ester solvents and alcohol solvents with respect to the total solvent content in the printing ink, and containing the printing ink binder. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The (a) high molecular weight polyol component, which is a constituent component of the polyurethane resin of the present invention, is not particularly limited, and various types having a number average molecular weight of 500 to 10,000 used as high molecular weight polyols of polyurethane resin are used. Can be used. Specifically, polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene diol (block and / or random) polytetramethylene ether glycol which are polymers such as ethylene oxide, propylene oxide, and tetrahydrofuran Ethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5
Aliphatic diols such as pentanediol, hexanediol and 1,8-octamethylenediol, bis (hydroxymethyl) cyclohexane, m- and p-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, Diols having a cyclic group such as 4,4'-bis (2-hydroxyethoxy) -diphenylpropane and the like; aromatic dicarboxylic acids such as phthalic anhydride, isophthalic acid, and terephthalic acid; adipic acid, maleic acid, fumaric acid; Succinic, oxalic, malonic, azelaic,
Polyester polyols obtained by dehydrating and condensing an aliphatic dicarboxylic acid such as sebacic acid; polyester polyols obtained by ring-opening polymerization of a cyclic ester compound; other known polymers such as polycarbonate polyols and polybutadiene glycols A polyol is exemplified.

The diisocyanate compound (b) which is a component of the polyurethane resin of the present invention is not particularly limited, and known aromatic, aliphatic and 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,
2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane-
1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate and the like are typical examples.

As the chain extender (c), which is a component of the polyurethane resin of the present invention, various known polyamine compounds can be used. Specific examples include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4-diamine and the like. Diamines having a hydroxyl group in the molecule, for example, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2
Polyamine compounds such as -hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine can also be used.

It is necessary to use a compound represented by the general formula (1) for the chain terminator (d), which is a component of the polyurethane resin of the present invention. Specific examples of the compound represented by the general formula (1) include n-octylamine, 2-ethylhexylamine, dodecylamine, tetradecylamine, hexadecylamine, stearylamine, and oleylamine when X is a hydrogen atom. Can be X is carbon number 1
In the case of 18 saturated or unsaturated hydrocarbon groups, di-n-octylamine, di-2-ethylhexylamine, distearylamine and the like are listed. When X is a hydroxyethyl group, oxyethylene dodecylamine, oxyethylene stearylamine and the like are listed. These (d) chain length terminators may be used alone or in combination of several kinds. Further, a chain terminator other than the compound represented by the general formula (1) can be used in combination without departing from the effects of the present invention. Specific examples of the chain terminator other than the compound represented by the general formula (1) include di-n-butylamine and mono-n
-Butylamine, diethanolamine, monoethanolamine and the like.

The compound represented by the general formula (1) must be contained in the entire chain length terminator in an amount of 30% by weight or more, preferably 50% by weight or more. If the amount of the compound represented by the general formula (1) is less than 30% by weight in the total chain length terminator, the re-solubility decreases, which is not preferable.

As a method for producing the polyurethane resin of the present invention, for example, a urethane prepolymer having isocyanate groups at both terminals of a high molecular polyol is prepared from a high molecular polyol and an excess of a diisocyanate compound. Methods for reacting with long terminating agents are listed.

In this production method, when the above-mentioned polyurethane prepolymer is produced, the isocyanate group of the diisocyanate compound is more than 1.3 g and less than 4.5 g equivalent when the hydroxyl group of the high molecular polyol is 1 g equivalent. The formulation is preferred. Optimally, the diisocyanate compound is blended so that the isocyanate group is more than 1.5 g equivalent and not more than 4.0 g equivalent. When the isocyanate group content is 1.3 g equivalent or less, the blocking resistance decreases, which is not preferable. If the isocyanate group exceeds 4.5 g equivalent, the resulting polyurethane resin tends to have poor adhesion.

In the reaction of a urethane prepolymer having an isocyanate group at both ends with a chain extender and a chain terminator, when the amount of the isocyanate group of the urethane prepolymer is 1 g equivalent, the chain It is preferable that the total of the amino groups in the extender and the chain terminator is 0.8 to 1.20 g equivalent. If the amino group content is less than 0.8 g equivalent, the blocking resistance is undesirably reduced. If the amino group exceeds 1.20 g equivalent, the chain extender remains unreacted in the polyurethane resin and produces an unpleasant odor, which is not preferable.

The production of the polyurethane resin in the present invention is carried out in the presence or absence of a solvent. As the solvent that can be used, aromatic solvents such as benzene, toluene, and xylene, which are well-known as solvents for printing inks; saturated hydrocarbon solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane;
Ester solvents such as butyl acetate; alcohol solvents such as methanol, ethanol, isopropanol and n-butanol; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone can be used alone or in combination. In order to obtain “non-toluene type ink”,
It is particularly convenient to use an ester solvent and / or a ketone solvent as a main component as the solvent used for producing the polyurethane resin of the present invention. The amount of the solvent used is such that the weight ratio of the polyurethane to the solvent is in the range of 100/0 to 10/90, preferably 60/40 to 20/80.

The polyurethane resin of the present invention obtained as described above is considered to have a structure in which the amino group of the chain terminator reacts with the isocyanate group at the terminal of the prepolymer to form a urea bond. . The number average molecular weight of the polyurethane resin of the present invention is preferably in the range of 5,000 to 100,000. When the number average molecular weight is less than 5,000, the bleeding phenomenon of a printing ink using this as a vehicle tends to occur, while 10,000
If it exceeds 0, the viscosity of the polyurethane resin solution becomes high, and "plate fogging phenomenon" tends to occur, which is not preferable.

A colorant, a solvent, and, if necessary, a surfactant, a wax, and other additives for improving ink fluidity and improving a surface film are appropriately blended with the polyurethane resin solution obtained by the above method, and the mixture is then ball milled. A printing ink composition meeting the object of the present invention can be obtained by kneading using an ordinary ink production apparatus such as a liquid, an attritor and a sand mill.

[0020]

The printing ink of the present invention has excellent properties in both "plate fogging" and "bleeding". Furthermore, in a "non-toluene-type ink" containing 90% by weight or more of a ketone-based solvent, an ester-based solvent, and an alcohol-based solvent in a solvent component of a printing ink, a particularly remarkable improvement effect of a "plate jam phenomenon" can be obtained. It has features.

[0021]

The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In each example, parts and% indicate parts by weight and% by weight, respectively.

Example 1 In a four-necked flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, 525.1 parts of poly (3-methylpentane adipate) diol having a number average molecular weight of 1,000 and 174.9 parts of isophorone diisocyanate were added. Charge, 1 under nitrogen flow
After reacting at 30 ° C. for 6 hours to produce a prepolymer,
300.0 parts of methyl ethyl ketone was added to obtain 1000 parts of a uniform urethane prepolymer solution. Then, 37.3 parts of isophorone diamine, 11.2 parts of dodecylamine,
A mixture consisting of 864.3 parts of methyl ethyl ketone and 582.2 parts of isopropyl alcohol was added to the urethane prepolymer solution and reacted at 50 ° C. for 3 hours. The polyurethane resin solution A thus obtained has a resin solid content concentration of 30% and a number average molecular weight by gel permeation chromatography (GPC) (hereinafter the number average molecular weight is G
It is by PC. ) Was 25,000.

Example 2 Using the same reactor as in Example 1, 1000 parts of the same urethane prepolymer solution as in Example 1 was prepared, and then 36.7 parts of isophorone diamine, 15.6 parts of oxyethylene dodecylamine, A mixture consisting of 870.2 parts of methyl ethyl ketone and 585.0 parts of isopropyl alcohol was added and reacted at 50 ° C. for 3 hours. The polyurethane resin solution B thus obtained has a resin solid content concentration of 30%,
The number average molecular weight of the polyurethane resin was 22,000.

Example 3 Using the same reactor as in Example 1, 1000 parts of the same urethane prepolymer solution as in Example 1 was prepared, and then 37.1 parts of isophoronediamine, 6.9 parts of dodecylamine,
6.1 parts of oxyethylene dodecylamine, 866.8 parts of methyl ethyl ketone and isopropyl alcohol 58
A mixture consisting of 3.4 parts was added and then reacted at 50 ° C. for 3 hours. The polyurethane resin solution C thus obtained had a resin solid content concentration of 30% and a number average molecular weight of the polyurethane resin of 23,000.

Example 4 Using the same reactor as in Example 1, 1000 parts of the same urethane prepolymer solution as in Example 1 was prepared, and then 37.6 parts of isophoronediamine, 5.5 parts of dodecylamine,
3.7 parts of di-n-butylamine, methyl ethyl ketone 8
A mixture consisting of 61.5 parts and 581.0 parts of isopropyl alcohol was added and then reacted at 50 ° C. for 3 hours. The polyurethane resin solution D thus obtained had a resin solid content concentration of 30% and a number average molecular weight of the polyurethane resin of 26,000.

Comparative Example 1 Using the same reactor as in Example 1, 1000 parts of the same urethane prepolymer solution as in Example 1 was prepared, and then 37.8 parts of isophoronediamine and 3.96 parts of monoethanolamine.
A mixture consisting of 1 part, 852.5 parts of methyl ethyl ketone and 576.3 parts of isopropyl alcohol was added, and the mixture was reacted at 50 ° C. for 3 hours. The polyurethane resin solution E thus obtained had a resin solid content concentration of 30% and a number average molecular weight of the polyurethane resin of 27,000.

Comparative Example 2 Using the same reactor as in Example 1, 1000 parts of the same urethane prepolymer solution as in Example 1 was prepared, and then 37.8 parts of isophoronediamine and 1.88 parts of monoethanolamine.
5 parts, 3.7 parts of di-n-butylamine, 855.8 parts of methyl ethyl ketone and 577.
A mixture of 8 parts was added, followed by a reaction at 50 ° C. for 3 hours. The polyurethane resin solution F thus obtained
Was 30% in resin solids concentration, and the number average molecular weight of the polyurethane resin was 27000.

Examples 1-4 and Comparative Examples 1-2 40 parts of titanium white (rutile type), polyurethane resin solutions A-F40 obtained in Examples 1-4 and Comparative Examples 1-2
And a mixture of 20 parts by weight of ethyl acetate, each of which was kneaded with a paint shaker to prepare a white printing ink, and six white inks shown in Table 1 were produced.

(Redissolution test) The obtained white ink was applied to a glass plate, air-dried for 10 seconds, and then a solvent (ethyl acetate / methyl ethyl ketone / isopropyl alcohol = 2/2 /).
1), and the re-dissolvability was visually observed. Table 1 shows the results. Evaluation criteria ○: 80% or more of the ink film dissolved ○ △: 60 to less than 80% of the ink film dissolved △: Less than 40 to 60% of the ink film dissolved △ ×: Less than 20 to 40% of the ink film dissolved ×: Almost remained without dissolution

(Adhesion test) The obtained white ink was printed on one side of a polyethylene terephthalate film (PET) or nylon film (NY) using a bar coater (No. 4), and dried at 40 to 50 ° C. A printed film was obtained. Then, an 18-mm-wide adhesive tape (registered trademark cellophane tape) made by Nichiban Co., Ltd. was stuck on the printing surface of the obtained printing film, and one end of the adhesive tape was rapidly peeled off in a direction perpendicular to the printing surface. Of the printed surface was visually observed. Evaluation criteria ：: 80% or more of the ink film remained on the film. Δ: 40% or more and less than 80% of the ink film remained on the film. X: Less than 40% of the ink film remained on the film.

[Table 1]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J034 BA08 CA02 CA13 CA14 CA15 CB01 CB03 DA01 DB04 DC02 DC50 DF01 DF02 DF14 DG02 DP19 HA01 HA07 HC03 HC12 HC22 JA01 QB05 RA07 4J039 AE04 BC07 BC16 BC20 BE12 CA04 EA48

Claims (5)

[Claims] 1. A polyurethane resin for printing ink comprising (a) a high molecular weight polyol, (b) a diisocyanate compound, (c) a chain extender and (d) a chain terminator.
(D) As a chain length terminator, the following general formula (1): (Wherein, R: a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, X: a hydrogen atom, a hydroxyethyl group, a carbon number of 1 to 1)
And a saturated or unsaturated hydrocarbon group (8). 2. The polyurethane resin for a printing ink according to claim 1, wherein the (d) chain terminator represented by the general formula (1) is contained in an amount of 30% by weight or more in the total chain length terminator component. 3. A printing ink binder comprising the polyurethane resin according to claim 1 or 2. 4. The polyurethane resin according to claim 1 or 2, wherein the polyurethane resin is dissolved in at least one solvent selected from the group consisting of ketone solvents, ester solvents and alcohol solvents. 4. The binder for a printing ink according to 3. 5. The printing ink according to claim 3, wherein at least one solvent selected from the group consisting of ketone solvents, ester solvents and alcohol solvents is contained in an amount of 90% by weight or more based on the total solvent content in the printing ink. A printing ink comprising the printing ink binder described in 1 above.