JPS6357680A - Binder for printing ink - Google Patents

Abstract

PURPOSE:To obtain the title binder which has excellent adhesiveness to a plastic film and gives a printing ink with excellent printability on a plastic film, by mixing a polyurethane resin and a specified acrylic resin. CONSTITUTION:A high-molecular weight polyol of a molecular weight of 500-3,000 is reacted with a diisocyanate compound and a chain extender in a solvent to give a solution which has a viscosity of 50-100,000cp (25 deg.C) and contains 15-60wt% polyurethane resin (A) of a molecular weight of 5,000-100,000. Then, component A is mixed with a solution (B) which has a viscosity of 50-100,000cp (25 deg.C) and contains 20-70wt% acrylic resin having in its molecule at least one kind of functional group selected from a quaternary ammonium salt group, a pyridinium salt group, and a sulfo (sulfonate) group in an amount of 5X10<-6>-5X10<-4>g equivalent per gram of resin solids and having a glass transition temperature of -20 deg.C or higher and a molecular weight of 3,000-200,000, in the weight ratio of A to B of 1/1-20/1.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a binder for printing ink.

More specifically, the present invention relates to a printing ink binder that exhibits excellent adhesion and printability to plastics as printing materials, particularly polypropylene, polyester, and nylon films.

[Prior Art] In recent years, various types of plastic films have been developed as packaging materials as packaging contents have become more complex and packaging technology has become more sophisticated.As a result, it has become necessary to appropriately select a film that is compatible with the contents. It is becoming more and more used.

Conventionally, rosin-modified maleic acid resins, nitrified cotton, polyamide resins, chlorinated polypropylene, polyurethane resins, resins made of vinyl chloride-vinyl acetate copolymers, polyester resins, etc. have been used as binder components for plastic film printing ink compositions. Among these, polyurethane resins have been used in increasing amounts in recent years because they exhibit excellent adhesion to various plastic films.

However, when polyurethane resin is used as a printing ink binder, it has poor printing suitability due to poor resolubility, and as a result, it has the disadvantage of causing so-called "plate jam" or "plate fog" phenomenon during printing. However, there are problems in that blocking resistance and pigment dispersibility are poor.

On the other hand, printing inks using acrylic resins are generally used for paper coatings and paper printing inks, and although they are known to have good printability, it is difficult to use acrylic resins for plastic films. There is a common misconception that it lacks practicality due to insufficient adhesion.

That is, at present, there is no printing ink that has excellent adhesion to various plastic films as printing materials and does not cause problems in terms of printability.

Therefore, in view of the above-mentioned technical background, there is a strong need for a versatile printing ink binder that has excellent adhesion and printability for any plastic film.

Therefore, considering the advantages and disadvantages of polyurethane resins and acrylic resins, it is expected that a mixture of polyurethane resins and acrylic resins will improve both adhesion and printability.

However, simply adding and mixing acrylic resin to polyurethane resin results in poor compatibility, resulting in a decrease in the stability of the resulting ink, which not only tends to cause the ink to separate, but also to reduce its adhesion to plastic films. This is not desirable.

[Problems to be Solved by the Invention] The present inventors have solved the above-mentioned problems that could not be solved by the conventional techniques, namely, for polypropylene, polyester, and nylon films as printing substrates. As a result of intensive research to develop a printing ink binder with excellent adhesion and printability, we developed a binder that combines a polyurethane resin with a specific proportion of an acrylic resin containing special functional groups in its molecule. We have discovered a completely new fact that all of the above-mentioned problems can be solved if a resin mixture prepared by the inventors of the present invention is used as a binder.

The present invention was completed based on this new knowledge.

[Means for Solving the Problems] The present invention provides a polyurethane resin (A) obtained by reacting a polymer polyol, a diisocyanate compound, and a chain extender, a quaternary ammonium base, a pyridium base,
The present invention relates to an ink binder which is mixed with an acrylic resin (B) containing in its molecule at least one functional group selected from the group consisting of sulfonic acid groups and sulfonic acid groups.

That is, in the present invention, in addition to various polyurethane resins, an acrylic resin having a special functional group in the molecule is blended in a specific ratio, and these are used as a binder, thereby making the conventional polyurethane resin the main binder. This solution solves the above-mentioned problems that could not be solved with printing ink.

[Function and Examples] The binder for printing ink of the present invention comprises a polymer polyol,
A polyurethane resin (A) obtained by reacting a diisocyanate compound and a chain extender, and at least one functional group selected from the group consisting of a quaternary ammonium base, a pyridium base, a sulfonic acid group, and a sulfonic acid group. It can be obtained by mixing the acrylic resin (B) contained in the molecule.

Examples of the polymeric polyol component which is a constituent component of the polyurethane resin (A) include polyether polyols such as polymers such as ethylene oxide, propylene oxide, and tetrahydrofuran, or copolymers thereof; ethylene glycol, ■, 2-propane; Diol, ■, 3-propanediol, 1,3-butanediol, l,4-butanediol, neopentyl glycol, bentanediol, hexanediol, octanediol, l,4-butynediol, diethylene glycol, triethylene glycol, diol Saturated or unsaturated low molecular weight glycols such as propylene glycol, adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, and speric acid. Polyester polyols obtained by dehydration condensation of dibasic acids such as , azelaic acid, and sebacic acid or their corresponding acid anhydrides; Polyester polyols obtained by ring-opening combination of cyclic ester compounds; Other polycarbonate polyols, Examples include various known polymer polyols that are generally used in the production of polyurethane, such as polybutadiene glycols and glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A. Among the above-mentioned polymer polyols, when a polymer polyol obtained from glycols and dibasic acids is used, up to 5 mol % of the glycol component can be replaced with the following various polyols. That is, for example, glycerin, trimethylolpropane, trimethylolethane, 1,2,8-hexanetriol, 1,2,4-butanetriol, pentaerythritol, sorbitol, etc. can be substituted.

The molecular weights of the various polymeric polyols mentioned above are appropriately determined in consideration of the solubility, drying properties, anti-blocking properties, etc. of the resulting polyurethane resin, and are usually in the range of 500 to 3,000. If the molecular weight is less than 500, printability tends to be poor due to decreased solubility;
If it exceeds 000, drying properties and blocking resistance will decrease.

Furthermore, within a range that does not deviate from the performance of the resulting polyurethane resin, a part of the high molecular polyol component can be replaced with low molecular polyols, and the amount used in the polyol component is usually 20% by weight. % or less, preferably 10% by weight or less. Examples of the low-molecular polyols include various low-molecular polyols used in the production of the polymer polyols. If the proportion of low molecular weight polyols used exceeds 20% by weight, the adhesion of the resulting printing ink composition to plastic films and the solubility in diluting solvents tend to decrease.

Examples of the diisocyanate compound that is a component of the polyurethane resin (A) include aromatic, aliphatic, and alicyclic diisocyanates. For example, l, 5
- Naphthylene diisocyanate, 4.4°-diphenylmethane diisocyanate, 4.4”-diphenyldimethylmethane diisocyanate, 4,4°-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, t,a-phenyl diisocyanate , l, 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,
Typical examples include dicyclohexylmethane-4,4°-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and methylcyclohexane diisocyanate.

In addition, chain extenders include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine,
Examples include dicyclohexylmethane-4,4°-diamine. Also, diamines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropyl Ethylenediamine and the like can be used as well. Furthermore, if necessary, a dialkylamine such as di-n-butylamine can also be used as a polymerization terminator.

As a method for producing the polyurethane resin of the present invention, first, a polymer polyol component and a diisocyanate compound are reacted under conditions in which there are an excess of isocyanate groups to prepare a prepolymer having incyanate groups at both ends of the polymer polyol, This can then be reacted with a chain extender and/or polymerization terminator in an appropriate solvent, or by reacting the polymer polyol component, diisocyanate compound, and chain extender and/or polymerization terminator once in an appropriate solvent. Although any one-step method of reacting with the polymer may be employed, the former method is preferred for the purpose of obtaining a uniform polymer solution. In these manufacturing methods, the solvents used are usually aromatic solvents such as benzene, toluene, and xylene, which are well known as solvents for printing inks; ester solvents such as ethyl acetate and butyl acetate; methanol and ethanol. , isopropanol, alcoholic solvents such as n-butanol; acetone, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone may be used alone or in combination of two or more.

When producing the polyurethane resin (A) used in the present invention by a two-step process, it is preferable to mix a chain extender and/or a polymerization terminator with the prepolymer according to the following criteria. That is, if the free isocyanate groups that the prepolymer has at both ends is 1 equivalent, the total equivalent of amino groups in the chain extender and/or polymerization terminator is 0.
．． It is preferably within the range of 9 to 1.30 equivalents. If the amino group is in excess of 1.30 equivalents, the chain extender and/or polymerization terminator remains unreacted,
This will have a negative impact on printed matter in terms of odor.

The molecular weight of the polyurethane resin (A) used in the present invention obtained as described above is preferably within the range of 5,000 to 100,000. If the molecular weight is less than 5,000, the drying properties, blocking resistance, film strength and oil resistance of printing inks using it as a binder will be poor, while if it exceeds 100,000, the viscosity of the polyurethane resin solution will be poor. There is a tendency for the gloss of the printing ink to decrease.

The resin solid content concentration of the polyurethane resin solution obtained as described above is not particularly limited, and is appropriately determined in consideration of workability during printing, etc., and is usually 15 to 60% by weight, and the viscosity is 50~100000cP (25℃)
Practically speaking, it is preferable to do so.

The acrylic resin CB), which is another binder component used in the present invention, contains at least 18 functional groups selected from the group consisting of quaternary ammonium bases, pyridium bases, sulfonic acid groups, and sulfonic acid groups. ,
It is preferable that the functional group is contained in an amount of 5X10-6 to 5XlO-4 gram equivalent per gram of solid content of the acrylic resin (B). If the content of the functional group is less than 5XLO-6 gram equivalent, the compatibility with the polyurethane resin (A) will be poor, the ink will separate, and the adhesion to the plastic film and pigment dispersibility will decrease. 5XlO-
If the amount exceeds 4 gram equivalents, the solubility in organic solvents decreases and becomes unstable, so that the effect of adding the acrylic resin (B) is no longer apparent. The acrylic resin (B)
As the main component, it is possible to use acrylic ester and/or methacrylic ester, which generally exhibit excellent effects on printability. Below, acrylic acid and/or
Or methacrylic acid is expressed as (meth)acrylic acid.

As a (meth)acrylic acid ester monomer, (meth)
Methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, (
(2-ethylhexyl meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, etc.
Generally commercially available products include meth)acrylic acid alkyl ester monomers and (meth)acrylic acid hydroxyalkyl ester monomers such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. In addition, a styrene monomer may be added in a range of 0 to 50 parts to 100 parts (parts by weight, hereinafter the same) of the total monomers of the acrylic resin (B) component and copolymerized.

The acrylic resin having a quaternary ammonium base in the molecule is composed of the (meth)acrylic acid ester monomer and a monomer containing a quaternary ammonium base, such as N-2
-methacryloyloxyethyl-N,N,N-trimethylammonium salt, N-3-methacryloyloxy-2
-Hydroxypropyl-N,N,N-trimethylammonium salt, N-3-methacryloylaminopropyl-N
, N,N-trimethylammonium salt, etc., or the above (meth)acrylic acid ester monomer and a monomer containing a tertiary amino group, such as 2-N,N-dimethylaminoethyl methacrylate, 2-N, N-diethylaminoethyl methacrylate, 8-N, N
- It can be obtained by copolymerizing with dimethylaminopropylacrylamide, etc., and then adding a quaternizing agent and causing the reaction. Examples of quaternizing agents include dimethyl sulfate,
Examples include dialkyl sulfates such as diethyl sulfate; halogenated hydrocarbons such as methyl chloride, benzyl chloride, methyl iodide, and ethyl bromide.

The acrylic resin containing a pyridium base in the molecule is composed of the (meth)acrylic acid ester monomer and a vinyl monomer containing a pyridium base, such as 4-vinyl-
N-propylpyridium salt, 2-vinyl-N-propylpyridium salt, etc. are copolymerized, or the above-mentioned (meth)acrylic acid ester monomer and a vinyl monomer containing a pyridyl group - 1 For example, 2-vinylpyridine, 4 - It can be obtained by copolymerizing with vinylpyridine or the like, and then quaternizing it with the quaternizing agent.

The acrylic resin containing a sulfonic acid group or a sulfonic acid group in the molecule is a combination of the above (meth)acrylic ester monomer and a monomer containing a sulfonic acid group or a sulfonic acid group, such as 2-acryloylamino-2-methyl-1. - Obtained by copolymerizing propanesulfonic acid or its salt, p-styrenesulfonic acid or its salt, etc.

The acrylic resin (B) contains the (meth)acrylic acid ester monomer and at least one member selected from the group consisting of the quaternary ammonium base, pyridium base, sulfonic acid group, and sulfonic acid group in a suitable solvent. It is prepared by reacting at 50 to 150°C in the presence of a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile. The acrylic resin (B
The solvent used in the preparation of ) may be the same as that used in the production of the polyurethane resin.

The molecular weight of the acrylic resin <8) used in the present invention, which is obtained as in the case of slanting, is 3,000 to 20,000.
A range of 0 is preferable. If the molecular weight is less than 3000, if this is used as a binder,
The film strength, drying property, blocking resistance, etc. of the printing ink are poor, and when it exceeds 200,000, the effect of improving resolubility decreases.

Furthermore, if the glass transition point (hereinafter referred to as Tg) is less than -20°C, blocking resistance tends to decrease. The viscosity and density are not particularly limited, and are determined appropriately considering workability during printing, and usually the density is 20 to 70%.
, a viscosity of 50 to 100,000 cP (25°C) is practically suitable.

The weight ratio (^)/(B) of polyurethane resin (A) and acrylic resin (B) obtained by slanting is 1/1~
It is preferable to mix them in a ratio of 20/1, and use them as is or further diluted to make a binder for printing ink.

If the weight ratio is less than 1 part, the adhesion will decrease, and if it exceeds 20/1, there will be no effect on printability, which is not preferable. This binder is mixed with a colorant, a solvent, and if necessary a surfactant for improving ink fluidity and a surface film, a wax, and other additives. Printing ink can be changed by kneading it using manufacturing equipment. The printing ink prepared in this way has excellent adhesion to various plastic films and has excellent re-dissolution properties during printing, so-called "
Clear printing results can be obtained without problems such as "plate jam" or "one plate fog".

Furthermore, it exhibits excellent properties such as blocking resistance and pigment dispersibility.

Production Example 1 A polymerization vessel was charged with 100 parts of poly(butylene adipate) glycol having a molecular weight of 12,000 and 22.2 parts of isophorone diisocyanate, and the mixture was heated at 100°C under a nitrogen stream for 6 hours.
The mixture was reacted for a period of time to obtain a prepolymer having a free isocyanate value of 3.3B%, and 81.5 parts of methyl ethyl ketone was added thereto to obtain a homogeneous solution of a urethane prepolymer. Then, 8.87 parts of isophorone diamine, 122.4 parts of methyl ethyl ketone and 101 parts of isopropyl alcohol were added.
In the presence of the 9 parts mixture, 203.7 parts of the urethane prepolymer solution was added, followed by reaction at 50°C for 3 hours. The polyurethane resin solution thus obtained is
Resin solid content concentration is 30%, viscosity is 3800cP (25℃
)Met.

Production Example 2 A polyurethane resin was obtained in the same manner as Production Example 1, using polyoxytetramethylene glycol having a molecular ffi of 2000 instead of poly(butylene adipate) glycol. The resin solution thus obtained had a resin solid concentration of 30% and a viscosity of 1000 cP (25°C).

Production example 3 75 parts of methyl ethyl ketone and 2 parts of isopropyl alcohol
A mixed solution consisting of 5 parts of methyl methacrylate, 97 parts of methacryloyloxyethyltrimethylammonium chloride, 3 parts of azobisisobutyronitrile was placed in a polymerization vessel, heated with stirring, and reacted at 7il'C for 5 hours. The acrylic resin solution thus obtained had a resin solid content concentration of 50% and a viscosity of 4200 cP (25°C
), Tg was 99°C.

Production example 4 75 parts of methyl ethyl ketone and 2 parts of isopropyl alcohol
5 parts, 99 parts of methyl acrylate, lO% of 2-acryloylamino-2-methyl-1-propanesulfonic acid
A mixed solution consisting of 10 parts of aqueous solution and 1 part of azobisisobutyronitrile was placed in a polymerization container and heated with stirring to 70°C.
The reaction was carried out for 5 hours.

The acrylic resin solution thus obtained has a resin solid content concentration of 50%, a viscosity of 1100 cP (at 25°C), and a Tg.
The temperature was 8°C.

Production Example 5 75 parts of methyl ethyl ketone and 2 parts of isopropyl alcohol
5 parts, 60 parts of methyl acrylate, 38 parts of styrene, 4
-2 parts of vinylpyridine, 1 part of azobisisobutyronitrile
The mixed solution consisting of 50% was placed in a polymerization container, heated while stirring, and reacted at 70° C. for 5 hours. Thereafter, 2.4 parts of benzyl chloride was added and the mixture was refluxed for 2 hours. The acrylic resin solution thus obtained has a resin solid content concentration of 50%,
The viscosity was 700 cP (25°C) and the Tg was 39°C.

Production Example 6 Triethanolamine 0.7 was added to the solution synthesized in Production Example 4.
1 part was added and the mixture was refluxed for 2 hours. The acrylic resin solution thus obtained has a resin solid content concentration of 50% and a viscosity of 11%.
00cP (25°C), Tg was 8°C.

Production Example 7 75 parts of methyl ethyl ketone and 2 parts of isopropyl alcohol
A mixed solution consisting of 5 parts of methyl methacrylate, 100 parts of azobisisobutyronitrile, and 1 part of azobisisobutyronitrile was placed in a polymerization vessel, heated with stirring, and reacted at 70°C for 5 hours. The acrylic resin solution thus obtained had a resin solid content concentration of 50%, a viscosity of 4300 cP (at 25°C), and a Tg of 100°C.

Production Example 8 75 parts of methyl ethyl ketone and 2 parts of isopropyl alcohol
A mixed solution consisting of 5 parts of methyl acrylate, 100 parts of azobisisobutyronitrile, and 1 part of azobisisobutyronitrile was placed in a polymerization vessel, heated with stirring, and reacted at 70'C for 5 hours. The acrylic resin solution thus obtained has a resin solid content concentration of 50%, a viscosity of 1300 cP (at 25°C), and a Tg of 8.
It was ℃.

Each mixture having the composition shown in Table 1 was milled in a ball mill to prepare eight white printing inks.

To 100 parts of each of the resulting printing inks, 35 parts of methyl ethyl ketone and 15 parts of isopropyl alcohol were further added to adjust the viscosity.

The prepared white ink was tested and evaluated based on the following items.

(Stability of Ink) The sedimentation property of the white pigment in the white ink whose viscosity was adjusted was observed and evaluated.

(Extractability) Using a rotogravure printing press, the above-mentioned adjusted ink was applied to a corona discharge stretched polypropylene film (hereinafter referred to as OPP), a polyethylene terephthalate film (hereinafter referred to as PE
(hereinafter referred to as NY) and nylon film (hereinafter referred to as NY). A cellophane adhesive tape was applied to the printed surface, and when one end of the cellophane adhesive tape was rapidly peeled off in a direction perpendicular to the printed surface, the condition of the printed surface was observed and evaluated.

(Blocking Resistance) The above adjustment ink was printed on NY using a rotogravure printing press. Place the printed surfaces on top of each other at a temperature of 40℃.
After holding at a humidity of 80% and a pressure of 1) cg/cm2 for 3 hours, the ink was peeled off and the degree of peeling of the ink was observed and evaluated.

(Resolubility) At the time when the above adjusted ink was printed on NY for 1 minute at a printing speed of ``toom'' on a rotogravure printing machine,
The presence or absence of clogging of the roll plate was evaluated by observation.

(Pigment dispersibility) Each of the above adjusted inks was printed on NY using a rotogravure printing machine, and the gloss of the printed surface was observed and evaluated.

[Margin below] From the above results, it can be seen that when the binder of the present invention is used, it exhibits excellent adhesion and printability to various plastic films.

[Effects of the Invention] The printing ink binder of the present invention has excellent preoperative properties and printability on various plastic films, so it can be applied to various uses as a highly versatile printing ink binder. .

Patent applicant: Toyo Ink Manufacturing Co., Ltd. Haka 1 person

Claims (1)

[Claims] 1. Polyurethane resin (A) obtained by reacting a polymeric polyol, a diisocyanate compound, and a chain extender.
and an acrylic resin (B) containing in its molecule at least one functional group selected from the group consisting of a quaternary ammonium base, a pyridium base, a sulfonic acid group, and a sulfonic acid group. Binder for ink. 2 The polyurethane resin (A) and the acrylic resin (B) have a weight ratio ((A)/(B)) of 1/1 to 20/
1. The binder for printing ink according to claim 1, which is 3 The acrylic resin (B) is the acrylic resin (
5 x 10^-^6~ of the above functional groups in 1 g of solid content of B)
The binder for printing ink according to claim 1, which contains 5×10^-^4 gram equivalent. 4 The glass transition point of the acrylic resin (B) is -2
The binder for printing ink according to claim 1, which has a temperature of 0°C or higher.