JPH1143640A - Printing ink binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printing ink binder which dries in a short time and has a blocking resistance while retaining its excellent adhesiveness by incorporating a polyurethane-polyurea resin obtd. by reacitng bis(isocyanatomethyl)cyclohexane, a high-molecular polyol, a chain extender, and if necessary a terminal reaction stopper into the same. SOLUTION: Bis(isocyanatomethyl)cyclohexane substantially contg. no halogen (20 ppm or lower) is used. A polyether polyol, pref. having a mol. wt. of 3006,000, is used as the high-molecular polyol. An example of the chain extender is ethylenediamine. Methanol, etc., are used as the terminal reaction stopper. The ratio of the number of isocyanate groups to the number of hydroxyl groups in the high-molecular polyol is pref. (1.1/1)-(3/1). The polyurethane-polyurea resin pref. has a wt. average mol.wt. of 5,000-500,000 and a viscosity of 50-100,000 mPa.s and is used in an amt. of 15-60 wt. %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder for a printing ink for a plastic film, and more particularly to a binder for a printing ink containing a polyurethane polyurea resin as a main component.

[0002]

2. Description of the Related Art In recent years, plastic films have been generally used as packaging materials, and accordingly, the demand for printing inks for plastic films has also increased. When a plastic film is used as a packaging material, printing is performed for decoration or surface protection of the plastic film. Printing ink for such printing has good adhesion to these various plastic films. Some high performance is required. Moreover, in order to respond to high-speed printing, its high performance must be exhibited in a short drying time.

Conventionally, polyurethane polyurea resins have been widely used as binders for printing inks used in such printing inks. In general, printing inks using a polyurethane polyurea resin as a binder have excellent adhesion to polyester and nylon films alone, but have insufficient adhesion to general-purpose polyethylene and polypropylene. In order to supplement the adhesive strength, a two-component reactive ink obtained by mixing a polyisocyanate compound with a polyurethane polyurea resin is used.

[0004] However, the two-pack reaction type ink has a disadvantage that a curing agent must be blended immediately before printing, which is inconvenient to handle, and is also subject to various restrictions in terms of pot life (pot life). Have. Therefore, various researches and developments have been made in the art on polyurethane polyurea resins which have good adhesiveness to various plastic films and can be used as a binder for one-component inks without the need to incorporate a polyisocyanate compound. Thus, although the adhesiveness is being improved to some extent, it also results in impairing the blocking resistance.

[0005] For example, a method of improving adhesion to various plastic films by using a modified chlorinated polypropylene having a specific polar group in the molecule (JP-A-4-1593)
No. 77, JP-A-7-82337, JP-B-7-3027
No. 8), a method of using a long-chain dibasic acid as a dibasic acid component of a polyester diol to enhance adhesion to various plastic films (Japanese Patent Publication No. 6-68088), and various plastics using a low molecular triol as a polyol component A method for enhancing the adhesion to a film and the blocking resistance (Japanese Patent Publication No. 5-73154),
A method of increasing the adhesion to various plastic films by using an alkylene oxide adduct of N-dialkylaminoalkylamine (Japanese Patent Publication No. 7-100771), using a diol as an essential component as a chain extender and a mixture with a diamine component. To increase the adhesion to various plastic films by using a compound having an aldehyde group as a chain extender (Japanese Patent Laid-Open No. 5-2570).
No. 22331), and a method of using a long-chain alkylenediamine as a chain extender to enhance the adhesiveness to various plastic films (Japanese Patent Application Laid-Open No. H8-217849). Although all of them use a special system to improve adhesion and blocking resistance, these inventions do not provide good adhesion in a short drying time and have a sufficient blocking resistance. Is not satisfied.

[0006]

As described above, various researches and developments have been made on polyurethane polyurea resins which can be used as a binder for one-pack type inks, but after all, excellent adhesiveness can be obtained in a short drying time. While one-part inks having sufficient blocking resistance at the same time have not yet been obtained, they are currently used with the properties of both or some of them being sacrificed to some extent. is there. The object of the present invention is to use a general polymer polyol component, a chain extender and, if necessary, various known compounds known as a terminal terminator, to thereby obtain a printed material such as polyester, nylon, or polyethylene.
An object of the present invention is to provide a one-pack type printing ink binder having sufficient blocking resistance while maintaining excellent adhesion to various plastic films such as polypropylene in a short drying time.

[0007]

The present inventors have made intensive studies on the above-mentioned problems in the prior art, and as a result, have found that a one-pack type printing obtained by using bis (isocyanatomethyl) cyclohexane as a diisocyanate compound. It has been found that a binder for ink has sufficient blocking resistance while maintaining extremely excellent adhesion to various plastic films such as polyester, nylon, polyethylene and polypropylene in a short drying time, and completes the present invention. Reached. That is, the present invention relates to a binder for a printing ink comprising a polyurethane polyurea resin obtained by reacting bis (isocyanatomethyl) cyclohexane with a polymer polyol, a chain extender and, if necessary, a terminal reaction terminator. It is.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the polymer polyol component of the present invention, various known ones generally used as a polymer polyol component of polyurethane polyurea resin polyurethane are used. For example, polyether polyols such as polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran; ethylene glycol, 1,2-
Propanediol, 1,3-propanediol, 1,3
-Butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,
Various known saturated and unsaturated low molecular weight glycols such as 5-pentanediol, hexanediol, octanediol, 1,4-butynediol, diethylene glycol, triethylene glycol and dipropylene glycol, or n-butyl glycidyl ether; Alkyl glycidyl ethers of ethylhexyl glycidyl ethers, glycidyl esters of monocarboxylic acids such as glycidyl versatate, dimer diols obtained by reducing dimer acid, adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, maleic acid Acids, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, dibasic acids such as sebacic acid or the corresponding acid anhydrides or dimer acids are dehydrated and condensed Polyester polyols are; cyclic ester compound polyester polyols obtained by ring-opening polymerization of; other polycarbonate polyols, polybutadiene glycols, bisphenol A
And various known polymer polyols generally used in the production of polyurethane polyurea resins, such as glycols obtained by adding ethylene oxide or propylene oxide to water. The molecular weight of the above-mentioned various polymer polyols is appropriately determined in consideration of the solubility, drying property, blocking resistance and the like of the obtained polyurethane polyurea resin, and is usually 300.
It is suitably in the range of 6000 to 6000, preferably in the range of 500 to 3000. If the molecular weight is less than 300, the printability tends to be inferior due to the decrease in solubility, while if it exceeds 6000, the drying properties and the anti-blocking properties tend to decrease.

In the present invention, bis (isocyanatomethyl) cyclohexane which is a non-yellowing type diisocyanate compound is used as the diisocyanate compound. This bis (isocyanatomethyl) cyclohexane is substantially bis (isocyanatomethyl) free of halogen.
Preferably, cyclohexane is used. In the present invention, substantially containing no halogen means that the content of the halogen element is 20 p
pm or less. Bis (isocyanatomethyl) cyclohexane used in the present invention includes 1,3-bis (isocyanatomethyl) cyclohexane and 1,4-bis (isocyanatomethyl) cyclohexane.

The bis (isocyanatomethyl) cyclohexane used in the present invention may be produced by any method, but those conventionally produced industrially are produced using phosgene. Therefore, it contains a large amount of halogen. Therefore, it is very difficult to make the isocyanate compound produced using phosgene substantially free of halogen.
Bis (isocyanatomethyl) without halogen atom
Cyclohexane can be obtained, for example, by a method of thermally decomposing the corresponding urethane compound (Japanese Patent Application Laid-Open No. Sho.
0-30832, JP-A-60-231640, etc.).
As a method for producing this urethane compound, a method of oxidatively reacting a diamino compound with carbon monoxide and an organic hydroxyl compound, or a method of reducing a dinitro compound, dinitroso compound, azo compound, azoxy compound and the like with carbon monoxide and an organic hydroxyl compound And a method of reacting a diamino compound with a dialkyl or diaryl carbonate (for example, JP-A-1-230550).
), A method of reacting a diamino compound with urea and an organic hydroxyl compound (for example, Japanese Patent Publication No.
No.) and the like. Further, as a method for producing bis (isocyanatomethyl) cyclohexane containing no halogen atom, there is also a method of directly obtaining a diamino compound and a diaryl carbonate (for example, JP-A No. 62-149654).

The one-pack type printing ink binder obtained by using the specific diisocyanate compound of bis (isocyanatomethyl) cyclohexane of the present invention is extremely excellent for various plastic films such as polyester, nylon, polyethylene and polypropylene. It has sufficient blocking resistance while maintaining the improved adhesiveness. In addition, by using bis (isocyanatomethyl) cyclohexane containing substantially no halogen atom as the diisocyanate compound, the adhesion and blocking resistance to various plastic films such as polyester, nylon, polyethylene, and polypropylene are further improved.

In the present invention, various known components can be used as the chain extender component. For example, ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, metaxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (Aminomethyl) cyclohexane is a typical example.
In addition, 2-hydroxyethylethylenediamine, 2-
Diamines having a hydroxyl group in the molecule such as hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and the like are also included.

In preparing a printing ink binder having a desired molecular weight as the polyurethane polyurea resin used in the printing ink binder of the present invention, a terminal reaction terminator is used as necessary. Specific examples of the terminal reaction terminator include methyl alcohol, ethyl alcohol,
n-propyl alcohol, isopropyl alcohol, n
-Butyl alcohol, monohydric alcohols such as isobutyl alcohol, monoethylamine, n-propylamine,
Monoamines such as diethylamine, di-n-propylamine and di-n-butylamine, and alkanolamines such as monoethanolamine and diethanolamine are exemplified.

The method for producing the polyurethane polyurea resin used in the binder for printing ink of the present invention comprises:
For example, a polymer polyol component is reacted with bis (isocyanatomethyl) cyclohexane, which is an organic diisocyanate compound, at an isocyanate group excess molar ratio,
Prepare a prepolymer having isocyanate groups at both ends of the polymer polyol, dilute with a solvent, and then increase the molecular weight with a chain extender, or react the polymer polyol, organic diisocyanate and chain extender at once Can be performed by a one-shot method, etc.
For the purpose of obtaining a uniform polymer solution, the former prepolymer method is preferred.

In this prepolymer method, the order of addition of the components during the prepolymerization reaction of the terminal isocyanate group is not particularly limited, and all the components are mixed sequentially or simultaneously, or if necessary, the prepolymer is mixed. Various methods conventionally used in this field, such as re-adding an organic diisocyanate monomer appropriately during the chemical reaction, can be employed. In producing the prepolymer, the ratio of the number of isocyanate groups to the number of hydroxyl groups in the high molecular weight polyol component is preferably 1.1 / 1 to 3/1. When this ratio is less than 1.1 / 1, heat resistance and coating strength are reduced, and when it is more than 3/1, the adhesion to various plastic films is reduced.

The amine equivalent of the chain extender in producing the polyurethane polyurea resin is 0.8 to 1.3 equivalents per 1 equivalent of the isocyanate group of the prepolymer.
Preferably it is 0.9 to 1.2 equivalents. When the amine equivalent is less than 0.8, the drying property, the blocking resistance, and the film strength are not sufficient. When the amine equivalent is more than 1.3, the chain extender remains unreacted and is printed on the printed matter. Odor tends to remain.

The equivalent ratio of the amine equivalent of the diamine in the chain extender to the hydroxyl equivalent of the monoalcohol or the amine equivalent of the monoamine in the chain terminator is in the range of 1/2 to 100/2. When the corresponding ratio is smaller than 1/2, the chemical resistance is reduced, and when it is larger than 100/2, the molecular weight is increased to increase the viscosity of the resin and the workability is reduced. The chain length terminator may be reacted before the chain extension reaction, added simultaneously with the chain extension agent, or added after the completion of the chain extension reaction to complete the reaction.

Solvents used for the production of these polyurethane polyurea resin solutions include those which are usually well known as solvents for printing inks, for example, alcohols such as methanol, ethanol, isopropanol and n-butanol; acetone, Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers such as dioxane and tetrahydrofuran; aliphatic hydrocarbons such as hexane and cyclohexane; esters such as ethyl acetate and butyl acetate; aromatics such as benzene, toluene and xylene Hydrocarbons; aprotic polar solvents such as dimethyl sulfoxide, N-methyl-2-pyrrolidone, dimethylformamide and the like, and mixtures of two or more thereof. The reaction can use a catalyst. Examples of the catalyst that promotes the urethanization reaction include tertiary amine catalysts such as triethylamine and dimethylaniline, and organometallic catalysts such as organotin and organozinc.

The polyurethane polyurea resin of the present invention thus obtained has a weight average molecular weight of 5,000 to 50.
0000, preferably 10,000 to 300,000. When the weight average molecular weight is less than 5000, the drying properties of the printing ink and coating film using this as a binder,
Blocking resistance and oil resistance are poor. 5000 on the other hand
If it exceeds 00, handling becomes difficult because the viscosity of the polyurethane polyurea solution is high, the resulting printing ink and coating film have low gloss and poor resolubility.

The concentration of the resin solids (polyurethane polyurea) in the polyurethane polyurea solution obtained according to the present invention can be set widely by appropriately adjusting the amount of the solvent used in consideration of workability in the application. Is usually 15 to 60% by weight, and the viscosity of the solution is
50 to 100000 mPa · s is practically suitable. The binder for printing ink of the present invention has excellent performance especially as a binder for special gravure ink. Applies to polyester, nylon, polyethylene,
A polypropylene film is suitable. 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 kneading the resulting mixture using an ordinary ink manufacturing apparatus such as a ball mill.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples, comparative examples, production examples and test examples, but the present invention is not limited to these examples. In each example, parts and% are based on weight.

Example 1 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with poly (1,4,4) having an average molecular weight of 2,000.
468.8 parts of (butylene adipate) glycol and 80 parts of 1,3-bis (isocyanatomethyl) cyclohexane having a halogen content of 2 ppm were charged and reacted at 90 ° C. for 18 hours under a nitrogen stream to obtain a free isocyanate content of 1 After preparing a 1.6% prepolymer, 365.9 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Then 21.1 parts of isophorone diamine,
5.3 parts of di-n-butylamine, methyl ethyl ketone 4
A mixture consisting of 88.1 parts and 488.1 parts of isopropanol was added to 914.7 parts of the urethane prepolymer solution and reacted at 50 ° C. for 6 hours. The polyurethane polyurea resin solution thus obtained has a resin solid content concentration of 30.
%, Viscosity was 1650 cps / 25 ° C.

Example 2 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with poly (1,1) having an average molecular weight of 2,000.
468.8 parts of 4-butylene adipate) glycol,
Hydrolytic chlorine content is 254 ppm (acidity HCl: 4
80 ppm of 1,3-bis (isocyanatomethyl) cyclohexane and reacted at 90 ° C. for 18 hours under a nitrogen stream to produce a prepolymer having a free isocyanate content of 1.6%. 365.9 parts were added to obtain a uniform urethane prepolymer solution. Next, 21.0 parts of isophorone diamine, 5.3 parts of di-n-butylamine, and 48 parts of methyl ethyl ketone were used.
A mixture consisting of 8 parts and 488 parts of isopropanol was added to 914.7 parts of the urethane prepolymer solution.
The reaction was carried out at 6 ° C. for 6 hours. The polyurethane polyurea resin solution thus obtained had a resin solid content concentration of 30% and a viscosity of 2300 cps / 25 ° C.

Comparative Example 1 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with poly (1, 1) having an average molecular weight of 2,000.
739.7 parts of 4-butylene adipate) glycol and 170 parts of isophorone diisocyanate were reacted at 90 ° C. for 8 hours under a nitrogen stream to produce a prepolymer having a free isocyanate content of 2.8%, and then 606.5 parts of methyl ethyl ketone. Was added to obtain a uniform urethane prepolymer solution. Next, 52.9 parts of isophorone diamine, 13.4 parts of di-n-butylamine, and methyl ethyl ketone 8
A mixture consisting of 35.4 parts and 835.4 parts of isopropanol was added to 1516.2 parts of the urethane prepolymer solution and reacted at 50 ° C. for 4 hours. The polyurethane polyurea resin solution thus obtained has a resin solid content concentration of 3
0% and a viscosity of 450 cps / 25 ° C.

Comparative Example 2 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with poly (1,1) having an average molecular weight of 2,000.
460.7 parts of 4-butylene adipate) glycol,
After 90 parts of isophorone diisocyanate was charged and reacted at 90 ° C. for 27 hours under a nitrogen stream to produce a prepolymer having a free isocyanate content of 0.5%, 367.1 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Next, 21 parts of isophoronediamine, di-n-
5.3 parts of butylamine, 489.6 of methyl ethyl ketone
And a mixture consisting of 489.6 parts of isopropanol and 550.7 parts of the urethane prepolymer solution.
The reaction was performed at 0 ° C. for 6 hours. The polyurethane polyurea resin solution thus obtained had a resin solid content concentration of 30% and a viscosity of 950 cps / 25 ° C.

Comparative Example 3 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with poly (1,1) having an average molecular weight of 2,000.
473.6 parts of 4-butylene adipate) glycol,
After 70 parts of hexamethylene diisocyanate was charged and reacted at 90 ° C. for 16 hours under a nitrogen stream to produce a prepolymer having a free isocyanate content of 0.5%, 362.4 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Then 19.3 parts of isophorone diamine,
4.9 parts of di-n-butylamine, methyl ethyl ketone 4
A mixture consisting of 81.2 parts and 481.2 parts of isopropanol was added to 906 parts of the urethane prepolymer solution, and reacted at 50 ° C. for 6 hours. The polyurethane polyurea resin solution thus obtained has a resin solid content concentration of 30.
% And a viscosity of 28000 cps / 25 ° C.

Example 3 A three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with poly-3- having an average molecular weight of 2,000.
270.5 methylpentylene adipate glycol
Parts, 53 parts of 1,3-bis (isocyanatomethyl) cyclohexane having a halogen content of 2 ppm were charged,
After reacting at 70 ° C. for 15 hours in a nitrogen stream to produce a prepolymer having a free isocyanate content of 2.9%, 362.4 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Then isophorone diamine 17.9
, 4.5-parts of di-n-butylamine, 222.4 parts of methyl ethyl ketone, and 222.4 parts of isopropanol were added to 685.9 parts of the urethane prepolymer solution, and reacted at 50 ° C. for 6 hours. The polyurethane polyurea resin solution thus obtained had a resin solid content concentration of 30% and a viscosity of 550 cps / 25 ° C.

Production Examples Using the polyurethane polyurea resin solutions obtained in Examples 1 to 3 and Comparative Examples 1 to 3 as binders, printing inks were prepared according to the following formulation. Polyurethane polyurea resin solution 100 parts Pigment (rutile type titanium oxide) 50 parts Methyl ethyl ketone 15 parts Toluene 15 parts Isopropanol 20 parts Alumina beads 200 parts

Each of the above-mentioned raw materials was ground for 4 hours with a pent shaker (manufactured by Red Devil Co.) to obtain a white printing ink. Using these printing inks, Bar Coater N
o. Polyethylene (P)
E), polypropylene (PP), polyester (PE
Printing was performed on the treated surface of each film of T) and nylon-6 (NY) to obtain a printed matter, which was dried. Drying condition is temperature 50
After heating at 30 ° C. for 30 seconds, it was allowed to stand at a temperature of 23 ° C. and a humidity of 50% for 60 seconds.

Test Example The following test was performed on the obtained printed matter. Table 1 shows the results. (I) Adhesiveness A Nichiban cellophane tape (18 mm width) was adhered to the printing surface, and the state of the printing surface when one end of the cellophane tape was rapidly peeled off in a direction perpendicular to the printing surface was observed. ：: extremely good (no peeling) ：: good (0 to 10% peeling) □: moderate (10 to 30% peeling) △: slightly poor (30 to 50% peeling) ×: poor (50 to 100% peeling)

(Ii) Blocking resistance The printing surface and the non-printing surface (treated surface or untreated surface) are overlapped, and 1.0 kg / cm ² at a temperature of 40 ° C. and a humidity of 60% RH.
Was applied, and after 24 hours, it was peeled off and the surface condition was observed. Drying conditions were as follows: after heating at 50 ° C for 30 seconds,
It was left still for 60 seconds at 3 ° C. and 50% humidity. A: No blocking at all. ：: Almost no blocking. Δ: Blocking considerably. X: Blocking is remarkable.

[0032]

[Table 1] Adhesion Blocking resistance Treated surface Untreated surface PE PP PET NY PE PP PET NY PE PP PET NY Example 1 ◎ ○ ◎ ◎ ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Example 2 ◎ ○ ◎ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ◎ ◎ Example 3 ◎ ○ ◎ ◎ ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Comparative Example 1 ◎ × ○ ◎ × × △ × ◎ ◎ △ × Comparative Example 2 ◎ × ○ ◎ × × △ × ◎ ◎ ◎ △ × Comparative Example 3 Unable to test due to poor pigment dispersion

[0033]

As is clear from the above test results,
The ink using the binder for printing ink of the present invention has sufficient blocking resistance while maintaining extremely excellent adhesion to various plastic films in a short drying time. Further, since the binder for printing ink of the present invention is a one-pack type, the printing ink using the binder does not need to be compounded with a curing agent immediately before printing as in a two-pack type, so that it is easy to handle, and the polyester to be printed is ,Nylon,
It can be used very advantageously for various plastic films such as polyethylene and polypropylene.

Claims (2)

[Claims] 1. A binder for a printing ink comprising a polyurethane polyurea resin obtained by reacting bis (isocyanatomethyl) cyclohexane with a polymer polyol, a chain extender and, if necessary, a terminal reaction terminator. . 2. The printing ink binder according to claim 1, wherein bis (isocyanatomethyl) cyclohexane containing substantially no halogen is reacted.