JPH07100772B2 - Binder for printing ink - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to binders for printing inks.

[0002]

2. Description of the Related Art Conventionally, as a binder for printing ink, a polyester diol having a molecular weight of 500 to 3,000, which is composed of 3-methyl-1,5-pentanediol and a dicarboxylic acid, an organic diisocyanate, and an amine chain extender has been used. Polyurethane resins which are derived and have an amine value of 0.1 to 20 are known (for example, JP-A-63-317562).

[0003]

However, although this product has boil resistance when printed and laminated with a two-component reactive ink used by mixing with a polyisocyanate curing agent immediately before printing, When printing with a liquid ink, there is a problem that the boil resistance is insufficient and peeling occurs from the ink coating layer, significantly impairing the appearance as a product.

[0004]

Means for Solving the Problems The present inventor has obtained a binder for printing ink which is excellent in boil resistance even as a one-pack type printing ink containing no polyisocyanate curing agent and is suitable for various plastic films. As a result of earnest studies, the present invention has been achieved. That is, the present invention is a branched alkanediol (a-1) having 5 to 10 carbon atoms.
A glycol component (a) consisting of a dicarboxylic acid component (b) and a polyester diol (A) having a number average molecular weight of 3,500 to 15,000, a low molecular weight glycol (B) having a molecular weight of less than 500, and an organic diisocyanate (C). Derived from an amine chain extender (D) and having an amine value of 0.2 to 2
It is a binder for printing inks, characterized by comprising 0 polyurethane resin.

Examples of the branched alkanediol (a-1) include 1,4-pentanediol, 2,5-hexanediol and 3-
Methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-
Hexanediol, 2-methyl-1,8-octanediol and mixtures of two or more thereof. Preferred of these is 3-methyl-1,5-pentanediol.

As the glycol component (a), other glycol (a-2) together with the branched alkanediol (a-1) is used.
May be used. Examples of (a-2) include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3
-Butanediol, 1,6-hexanediol, 1,8-octamethylenediol, neopentyl glycol, 1,9-
Examples include nonanediol, bishydroxymethylcyclohexane, bishydroxyethylbenzene, and alkyl dialkanolamine. In this case, based on the weight of the glycol component (a), the branched alkanediol (a-
The amount of 1) is usually 20% or more, preferably 35% or more, more preferably 50% or more. If the amount of (a-1) is less than 20%, the redissolvability of the ink is insufficient.

Examples of the dicarboxylic acid component (b) include adipic acid, azelaic acid, sepacic acid, succinic acid, glutaric acid, maleic acid, fumaric acid, isophthalic acid and terephthalic acid, and mixtures of two or more thereof. To be Of these, preferred is adipic acid.

In the present invention, the number average molecular weight (by hydroxyl value measurement) of the polyester diol (A) is usually
It is 3,500 to 15,000, preferably 4,000 to 10,000. When the molecular weight is 3,500 or less, the laminated film has poor boil resistance, and bubbles are partially generated, resulting in poor appearance. When the molecular weight exceeds 15,000, the ratio of the low molecular weight glycol (B) used in combination increases, and it becomes difficult to dissolve it in the solvent, resulting in poor resolubility of the ink.

The polyester diol (A) may be used alone or, in some cases, a polyester diol derived from the other glycols (a-2) and (b) may be used together with (A). In this case, the amount of (a-1) based on the total amount of polyester diol is usually 20% or more, preferably 3
It is used in combination so as to be 5% or more, more preferably 50% or more.

In the present invention, examples of the low molecular weight glycol (B) having a molecular weight of less than 500 are those exemplified as (a-1) and (a-2) in the section of the polyester diol, and alkylene oxide low molar adducts thereof. , A low molar addition product of alkylene oxide of bisphenol A, and the like. Examples of each alkylene oxide include alkylene oxides having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, butylene oxide, etc.).

The amount of the low molecular weight glycol (B) used is
Usually 20% based on the weight of the polyester diol
Below. If it exceeds 20%, the re-solubility of the ink will be reduced.

In the present invention, the amount of the polyester diol (A) and the low molecular weight glycol (B) used is
The weighted average value of the number average molecular weights of (A) and (B) is 500 to 40.
The amount is 00, preferably in the range of 700 to 3,000. If the weighted average value of the molecular weight is less than 500, the film of the polyurethane resin becomes hard, and when it is used as an ink, the adhesiveness and re-dissolvability become poor. On the other hand, the weighted average molecular weight is 4,000
When it exceeds 0, the resin film becomes soft, and when used as an ink, the coating film has poor adhesion resistance and oil resistance.

Examples of the organic diisocyanate (C) used in the present invention include hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate, 2,6-diisocyanate methylcaproate and bis (2 -Isocyanate ethyl) fumarate, bis (2-isocyanate ethyl) carbonate, 2-isocyanate ethyl-2,6-diisocyanate Hexanoate and other aliphatic diisocyanates; isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexyl Cilendiisocyanate, methylcyclohexylene diisocyanate (hydrogenation
TDI), bis (2-isocyanatoethyl) 4-cyclohexene-1,2-dicarboxylate, and other alicyclic diisocyanates; xylylene diisocyanate, tetramethylxylylene diisocyanate, diethylbenzene diisocyanate, and other araliphatic diisocyanates; tolylenediene Isocyanate (TDI), diphenylmethane diisocyanate (MDI), modified MDI (carbodiimide modified MDI, etc.),
Aromatic diisocyanates such as naphthalene diisocyanate; and mixtures of two or more thereof. Preferred among these (C) are aliphatic diisocyanates, alicyclic diisocyanates and araliphatic diisocyanates.

The amine chain extender (D) used in the present invention includes aliphatic diamines {ethylenediamine, hexamethylenediamine, 1,2-propylenediamine, 2,2,4-trimethylhexamethylenediamine, N- (2-
Hydroxyethyl) ethylenediamine, N, N'-bis (2-
Hydroxyethyl) ethylenediamine, etc., alicyclic diamine (isophoronediamine, 4,4'-dicyclohexylmethanediamine, isopropylidenedicyclohexyl-
4,4'-diamine, 1,4-diaminocyclohexane, etc.),
Aromatic diamines (4,4'-diaminodiphenylmethane etc.), Aroaliphatic diamines (xylenediamine etc.),
Examples include hydrazine, dihydrazide (such as dihydrazide adipate), and the like, and mixtures of two or more thereof. Of these (D), preferred are aliphatic diamines and alicyclic diamines.

If necessary, a polymerization terminator may be used. Examples of the polymerization terminator used include monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol and iso-butyl alcohol; monoethylamine, n-propylamine, diethylamine, The-
Examples thereof include monoamines such as n-propylamine and di-n-butylamine; and hydroxylmonoamines such as monoethanolamine and diethanolamine.

Illustrating the production method of the polyurethane resin in the present invention, a urethane prepolymer having isocyanate groups at both ends is prepared from polyester diol (A), low molecular weight glycol (B), and excess organic diisocyanate (C). Alternatively, it can be produced by a prepolymer method in which an amine chain extender (D) is further reacted.

In the production of the urethane prepolymer, the equivalent ratio of the isocyanate group of the organic diisocyanate (C) to the total of the hydroxyl groups of the polyester diol (A) and the low molecular weight glycol (B) is usually 1.1 / 1.0 to.
It is 3.0 / 1.0, preferably 1.2 / 1.0 to 2.0 / 1.0. The amine chain extender (D) is used in excess with respect to the isocyanate groups of the prepolymer. For example, the amine chain extender (D) is usually 1.02 to 1.30 equivalents, preferably 1.05 to 1 equivalent of isocyanate group of the prepolymer.
The amount is 1.20 equivalents.

When a polymerization terminator is used if necessary, the polymerization terminator may be added before the chain extension reaction and reacted, or at the same time as the chain extension agent, or after the chain extension reaction is completed. Any method such as stopping the reaction may be used.

In the above-mentioned method, the polymerization is carried out in the presence or absence of a solvent. When it is carried out in the absence of the solvent, the solvent is added later, or once a solid resin is produced, it is dissolved in the solvent. Can be done. In order to obtain a uniform polymer solution, it is preferable to carry out the polymerization in the presence of a solvent.

Usable solvents are ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, etc.), aromatic hydrocarbons (toluene, xylene, etc.). , Alcohol (methanol, ethanol, isopropyl alcohol, etc.), polyhydric alcohol derivative (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), amide (dimethylformamide, etc.) sulfoxide (dimethyl sulfoxide, etc.) and two or more of these Mixed solvent of. Of these, preferred are acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, tetrahydrofuran, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and these. It is a mixed solvent of two or more kinds of. The amount of the solvent used is such that the weight ratio of the polyurethane resin to the solvent is in the range of 100/10 to 10/90, preferably 80/20 to 20/80.

The resin constituting the binder for the printing ink of the present invention may be the polyurethane resin alone, or may be used in combination with a conventionally known resin as another binder for the printing ink, if necessary. Other resins that can be used in combination include
Polyamide, nitrocellulose, polyacrylates,
Polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, chlorinated polyolefin, styrene-butadiene rubber,
Examples thereof include epoxy resin and rosin resin. When used in combination, the content of the other resin is usually 50% by weight or less in the solid content of the binder.

The binder for printing inks of the present invention is usually one in which the resin component containing the polyurethane resin is a solution of the solvent as exemplified above. The resin concentration in the binder of the present invention is usually 10 to 100% by weight, preferably 20 to 80%. Viscosity is usually 50-500,000 CPS / 20
C., preferably 100 to 100,000 cps / 20.degree.

The weight average molecular weight of the polyurethane resin is usually 5,000 to 500,000, preferably 10,000 to 200,000. If it is less than 5,000, the ink coating film has poor adhesion resistance. If it exceeds 500,000, the re-dissolvability of the ink will be poor.

The amine value (equivalent to polyurethane resin solid content) of the polyurethane resin is usually 0.2 to 20, preferably 1 to 10.
Is. If it is less than 0.2, the adhesion of the ink to the film will be poor. On the other hand, if it exceeds 20, the molecular weight of the polyurethane resin becomes small and the adhesion resistance of the ink coating film becomes poor.

The amount of the branched alkanediol component having 5 to 10 carbon atoms in the polyurethane resin is usually 10 to 10 on a weight basis.
It is 40%, preferably 20-40%. If it is less than 10%, the redissolvability of the ink is insufficient.

The binder for printing inks of the present invention has excellent performance as a binder for special gravure inks. Suitable applications include polyester films, nylon films, polypropylene films, polyethylene films, cellophane films and the like.

The printing ink binder of the present invention can be used in the same manner as in the case of the conventional ink binder. That is, a printing ink can be obtained by adding a pigment and, if necessary, an additive such as a pigment dispersant to the binder of the present invention and mixing them using an ordinary ink manufacturing apparatus such as a ball mill.

The formulation examples of the printing ink using the binder of the present invention are as follows (% represents% by weight). Binder (amount of solid content) of the present invention 10 to 20% Pigment 5 to 40% Other resins 0 to 10% Solvent (including solvent in resin composition) 40 to 75% Additive Appropriate amount

The binder of the present invention may be used for a one-pack type printing ink, but may also be used for a two-pack type printing ink in combination with a polyisocyanate curing agent. In this case, as the polyisocyanate-based curing agent, for example, an adduct body synthesized from 1 mol of trimethylolpropane and 3 mol of 1,6-hexamethylene diisocyanate, tolylene diisocyanate or isophorone diisocyanate; 1,6-hexamethylene diisocyanate or isophorone diisocyanate An isocyanurate group-containing trimer synthesized by cyclic trimerization of an isocyanate group of; a partial burette reaction product synthesized from 1 mol of water and 3 mol of 1,6-hexamethylene diisocyanate and a mixture of two or more thereof. It is suitable. The amount added is usually 0.5 to 10% by weight based on the ink. The printing method using the printing ink using the binder of the present invention may be the same as the case of the conventional special gravure ink.

[0030]

The present invention will be further described with reference to the following examples, but the present invention is not limited thereto. Example,
In the production examples and comparative examples, "part" means part by weight and "%" means% by weight. Example 1 242.5 parts of poly (3-methylpentylene adipate) diol having a number average molecular weight of 6260 (as measured by hydroxyl value), 7.0 parts of 1,4-butanediol and 38.7 parts of isophorone diisocyanate (IPDI) were mixed, and at 130 ° C. Let react for 3 hours
A urethane prepolymer with an NCO% of 1.77 was obtained. Next, add 250 parts of methyl ethyl ketone (MEK) and 250 parts of toluene,
The homogenized solution was put into a solution in which 11.9 parts of isophoronediamine was dissolved in 200 parts of isopropyl alcohol (IPA). After the completion of charging, the temperature was raised and the reaction was carried out at 50 ° C. for 5 hours. The polyurethane resin solution thus obtained had a concentration of 30
%, The viscosity was 1100 cps / 20 ° C. This resin had an amine value of 4.3 and a molecular weight of 57,000.

The molecular weight of the polyurethane resin was measured by the following method. [Measurement of molecular weight] A tetrahydrofuran solution containing 0.1% of polyurethane resin was prepared, and GPC device HL manufactured by Tosoh Corporation was prepared.
Injection volume 100 μl using C-8020, column GMH6 × 2,
The weight average molecular weight was measured with an RI detector at a flow rate of 1.0 ml / min.

Using the obtained polyurethane resin solution as a binder, printing ink was prepared according to the following formulation.

The above raw materials were placed in a steel can having an internal volume of 500 ml and kneaded for 1 hour with a paint conditioner (manufactured by Red Devil Co.) to obtain a printing ink I.

Example 2 254.6 parts of poly (3-methylpentylene adipate) diol having a number average molecular weight of 5220, 3.0 parts of ethylene glycol and 32.5 parts of IPDI were mixed and reacted at 130 ° C. for 3 hours to obtain NCO.
% Urethane of 1.40 was obtained. Then MEK250
Parts and 250 parts of toluene were added, and the homogenized solution was poured into a solution of 9.9 parts of isophoronediamine dissolved in 200 parts of IPA. After the completion of charging, the temperature was raised and the reaction was carried out at 50 ° C for 5 hours.
The polyurethane resin solution thus obtained had a concentration of 30% and a viscosity of 1500 cps / 20 ° C. The amine value of this resin is 3.6
And the molecular weight was 68,000. A printing ink II was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Example 3 225.4 parts of poly (3-methylpentylene adipate) diol having a number average molecular weight of 4040, 6.6 parts of 1,6-hexanediol and 44.6 parts of IPDI were mixed and reacted at 130 ° C. for 3 hours to be NC.
A urethane prepolymer having an O% of 2.71 was obtained. Then MEK250
Parts and 250 parts of toluene were added, and the homogenized solution was poured into a solution prepared by dissolving 23.4 parts of 4,4′-dicyclohexylmethanediamine in 200 parts of IPA. After the addition is completed, the temperature is raised to 50 ° C.
The reaction was carried out for 5 hours. The polyurethane resin solution thus obtained had a concentration of 30% and a viscosity of 600 cps / 20 ° C. This resin had an amine value of 8.3 and a molecular weight of 30,000. A printing ink III was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Comparative Example 1 257.3 parts of poly (3-methylpentylene adipate) diol having a number average molecular weight of 2020 and 42.4 parts of IPDI were mixed to obtain 1
A urethane prepolymer having an NCO% of 1.78 was obtained by reacting at 30 ° C. for 3 hours. Next, 250 parts of MEK and 250 parts of toluene were added to obtain a uniform solution, and 13.0 parts of isophoronediamine was added to IPA20.
It was poured into a solution dissolved in 0 part. After charging, raise the temperature to 5
The reaction was carried out at 0 ° C for 5 hours. The polyurethane resin solution thus obtained had a concentration of 30% and a viscosity of 600 cps / 20 ° C. This resin had an amine value of 4.7 and a molecular weight of 51,000. A printing ink IV was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Comparative Example 2 212.1 parts of poly (3-methylpentylene adipate) diol having a number average molecular weight of 1050 and 67.3 parts of IPDI were mixed to obtain 1
A urethane prepolymer having an NCO% of 3.04 was obtained by reacting at 30 ° C. for 3 hours. Next, 250 parts of MEK and 250 parts of toluene were added, and a uniform solution was prepared by adding 20.6 parts of isophoronediamine to IPA20.
It was poured into a solution dissolved in 0 part. After charging, raise the temperature to 5
The reaction was carried out at 0 ° C for 5 hours. The polyurethane resin solution thus obtained had a concentration of 30% and a viscosity of 220 cps / 20 ° C. This resin had an amine value of 7.5 and a molecular weight of 33,000. A printing ink V was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Comparative Example 3 241.3 parts of poly (butylene adipate) diol having a number average molecular weight of 6100, 7.1 parts of 1,4-butanediol and IPDI 3
9.5 parts were mixed and reacted at 130 ° C. for 3 hours to obtain a urethane prepolymer having an NCO% of 1.73. Next, 250 parts of MEK and 250 parts of toluene were added, and a uniform solution was added to a solution in which 12.1 parts of isophoronediamine was dissolved in 200 parts of IPA.
After the completion of charging, the temperature was raised and the reaction was carried out at 50 ° C for 5 hours. The polyurethane resin solution thus obtained had a concentration of 30% and a viscosity of 1200 cp.
It was s / 20 ° C. The resin had an amine value of 4.1 and a molecular weight of 60,000. A printing ink VI was obtained in the same manner as in Example 1 except that the obtained resin solution was used as a binder.

Using each of the printing inks I to VI obtained in Examples 1 to 3 and Comparative Examples 1 to 3, a surface-treated polypropylene film (abbreviated as 0PP) polyester film (abbreviated as PET) with a gravure proofing machine. Then, the surface-treated nylon film (abbreviated as NY) was printed to obtain a printed matter. The following performance test was performed on the obtained printed matter.

[Performance test items and test method] (1) Re-dissolvability Dissolve the ink coating film by dropping one drop of solvent (MEK 40 parts, toluene 40 parts, IPA 20 parts mixed solvent) on the PET printing surface with a void. The state of doing was observed.

(2) Adhesiveness Nichiban Cello tape (12 mm width) was attached to the printed surface, and one end of this Nichiban Cello tape was rapidly peeled in a direction perpendicular to the printed surface to observe the state of the printed surface.

(3) Adhesion resistance The printed surface and the non-printed surface are overlapped, and the temperature is 40 ° C. and the humidity is 60% R.
In H., a load of 1.0 kg / cm ² was applied and after 24 hours, it was peeled off and the surface condition was observed.

(4) Oil resistance The printed matter was immersed in rapeseed oil at 25 ° C. for 24 hours, and the surface condition was observed.

(5) Boil resistance The urethane printed material {a solution of Eunoflex [manufactured by Sanyo Kasei Co., Ltd.] diluted with ethyl acetate to a solid content of 5%] was applied to NY printed matter, and the surface treatment was performed after solvent drying. A non-stretched polypropylene film was pressure bonded and left at 40 ° C. for 2 days to prepare a laminated film. 90 this laminated film
The surface condition after immersing in hot water at ℃ for 60 minutes was observed.

Judgment of each test result is ⊚ extremely good, ○ good, Δ a little bad, and × bad. The results of the above tests are shown in Table 1.

[0046]

[Table 1]

[0047]

The binder of the present invention provides a binder for ink which is excellent in boil resistance of a laminated product when printed with a one-pack type ink. The binder of the present invention gives an ink with less defective appearance of a laminated film after boil treatment, as compared with a binder using a conventional polyurethane resin. In addition, the binder of the present invention provides a printing ink suitable for various plastic films having excellent adhesiveness, oil resistance, and redissolvability.
Because of the above effects, the binder of the present invention is particularly suitable as a binder for special gravure ink (for polyester film, nylon film, polypropylene film, cellophane film, etc.). Further, since the binder of the present invention has excellent properties such as adhesiveness, it can be used not only as a binder for printing inks but also as a binder for paints or as a coating material for woven fabrics, nonwoven fabrics, etc., and is extremely useful. Is.

Claims (2)

[Claims] 1. A branched alkanediol (a having 5 to 10 carbon atoms)
-1) a glycol component (a) and a dicarboxylic acid component (b) having a number average molecular weight of 3,500 to 15,000, a polyester diol (A), a low molecular weight glycol having a molecular weight of less than 500 (B), and an organic diisocyanate ( C) and an amine chain extender (D), and has an amine value of 0.2.
A binder for printing inks, which is composed of ~ 20 polyurethane resins. 2. The binder according to claim 1, wherein the weight average value of the number average molecular weights of (A) and (B) constituting the polyurethane resin is 500 to 4,000.