JPH04103623A - Polyester resin and printing ink composition for metal using the same - Google Patents

Abstract

PURPOSE:To obtain the subject resin having suitability to aqueous overprinting varnishes without causing misting in using thereof as a resin for metal printing inks having washability with water by copolymerizing a specific polyoxyethylene ether, etc. CONSTITUTION:(A) A polyhydric alcohol (e.g. ethylene glycol) is mixed and reacted with (B) a monohydric alcohol, expressed by formula I (R1 is 8-26C alkyl, etc.; (n) is 3-70) or formula II (R2 is 8-26C alkyl, etc.) and having >=10 HLB value, (C) a polyfunctional carboxylic acid (e.g. adipic acid) and (D) a monofunctional carboxylic acid such as lauric acid so as to provide (1:1.1) to (1:2.5) ratio of the components [(A)+(B)] to the components [(C)+(D)] and 3-60% equiv. ratio of the component (B) to the components [(A)+(B)]. Thereby, the objective resin is obtained.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to polyester resins, and particularly to polyester resins useful as binders for metal printing inks that have excellent compatibility with water-based overprint varnishes, and polyester resins using the same. An object of the present invention is to provide a printing ink composition for metals.

<Prior Art> Conventionally, as printing inks for metals, printing inks whose main vehicle components are resins such as alkyd resins, polyester resins, and epoxy resins and solvents such as mineral oil have been used.

In addition, overprinting is commonly performed to improve the adhesion and abrasion resistance of the printed film, and the varnishes used for overprinting are resins such as alkyd resin, polyester resin, acrylic resin, and epoxy resin, and melamine resin. , solvent-based products consisting of a curing agent such as benzoguanamine resin and a solvent such as mineral oil were widely used.

When printing on metal surfaces, offset printing machines or dry offset printing machines were used, and overprints were applied onto the ink film using a coater, etc., and baked at 130 to 200°C. .

However, recently, there has been a noticeable shift from solvent-based overprint varnishes to water-based varnishes in the metal printing field due to air pollution issues related to solvents, as well as hygiene and safety issues in the working environment. It's coming. As a result, printing inks for metals have also been required to have sufficient suitability for aqueous overprint varnishes.

In response to this requirement, when aqueous overprint varnish is applied to conventional metal printing ink, phenomena such as repellency on the coating surface and penetration of the varnish into the ink film occur.
As a result, it lacks gloss or adhesion, etc.
This caused a significant deterioration in the quality of the coating film.

As a method of imparting such aqueous overprint suitability, at least a portion of the solvent of the printing ink contains glycol.
A printing ink for metals (Japanese Patent Publication No. 22331/1983) using glycol, glycol ether, or glycol ester has been proposed.

Moreover, in JP-A No. 62-295974, the number of carbon atoms is 4 to 8.
The use of alkylene glycol solvents in
No. 295975 describes the use of polyoxyalkylene diol-based solvents, JP-A-62-295976 describes the use of polyoxyalkylene alkyl ether-based solvents, and JP-A-64-60670 describes the use of polyoxyalkylene alkyl esters. The use of solvents has been proposed.

However, although the use of these solvents is effective in imparting suitability for water-based overprints, simply replacing conventional solvents with these solvents tends to increase printing ink misting, degrading the working environment. It was an invitation.

On the other hand, JP-A-2-24315 discloses a technique for imparting aqueous overprint suitability and reducing misting by using polyester A resin modified with rosin alcohol; In JP-A No. 2-127485, a polyester resin partially modified with alcohol having a carbon number of 7 to 26 is used.
A Bossester resin using 26 branched saturated monocarboxylic acids has been proposed to be similarly effective.

Although these printing inks for metals using polyester resin as a binder have effects such as suitability for water-based overprints and reduction of misting, they still require the use of organic solvents to clean the printing ink on the printing plate. The work environment was not adequate.

<Problems to be Solved by the Invention> The present invention attempts to solve the above-mentioned problems of the prior art. An object of the present invention is to provide a polyester resin for printing ink and a printing ink composition for metal using the same.

Means for Solving the Problems> As a result of intensive research to solve the above problems, the inventors found that a polyester resin modified with a specific alcohol solves the above problems, and completed the present invention.

That is, the invention of claim 1 comprises an alcohol component (A) consisting of a polyhydric alcohol and a partial alcohol, and a carboxylic acid component (B) consisting of a polyhydric carboxylic acid and, if necessary, a partial carboxylic acid. In the polyester resin obtained by the reaction, the ratio of the alcohol component (A) to the carboxylic acid component (B) is 1:1.1 to 1:2.
5 (equivalent ratio), and the alcohol component (A
), 3% to 60% (equivalent ratio) is polyoxyethylene ether represented by -maximum N] and/or polyoxyethylene ester represented by -maximum [11] with an HLB value of 10 or more. The present invention provides a polyester resin having the following properties.

1] R2-C-0-(CH2CH□O), H...-maximum [
11] The invention of claim 2 is a printing ink composition for metals containing resin, pigment, and solvent as main components, characterized in that the polyester resin of claim 1 is contained in the printing ink in an amount of 5% by weight or more. The present invention provides a printing ink composition for metals.

The present invention will be explained in detail below.

The polyester resin according to the present invention has a carboxylic acid component (
B) and alcohol component (A) at 1:1.1~], :2
．． It is necessary to carry out the reaction at a ratio of 5 (equivalent ratio of hydroxyl groups to carboxyl groups). When printing on metal materials, the ink film is hardened and dried by baking. During the process, this baking is mainly caused by crosslinking of the curing agent in the printing ink and/or overprint varnish with the free hydroxyl groups of the resin in the printing ink and overprint varnish. It is necessary to react so that as many free hydroxyl groups as are necessary for crosslinking remain in the polyester resin. If the alcohol component is less than the above ratio, there is a greater risk of gelation, and the baking does not react sufficiently with the curing agent during drying, resulting in poor drying.

Moreover, if the above ratio is exceeded, it becomes difficult to synthesize the resin, such as making it impossible to obtain a high molecular weight resin. Here, among the alcohol components (A) constituting the polyester resin, polyhydric alcohols include ethylene glycol, propylene glycol, butylene glycol, hexylene glycol,
Examples include neopentyl glycol, trimethylolpropane, glycerin, and pentaerythritol.

Further, as the monohydric alcohol, it is essential to use a specific amount of a compound represented by -maximum [1] and/or -maximum [II). - In the monohydric alcohol represented by maximum [I] and/or - maximum [■], the number of carbon atoms of R,, R2 must be in the range of 8 to 26, and the number of carbon atoms is 8
If it is less than 27, problems will arise in the dispersibility of the pigment, and if it is 27 or more, the reactivity for obtaining a polyester resin will be lacking.

In addition, n is a real number in the range of 3 to 70, and if n is less than 3, suitability for water-based overprint varnish cannot be obtained;
If it exceeds 0, problems will occur in the reaction for obtaining polyester resin.

Furthermore, in the above-mentioned - slight alcohol, it is necessary that the total carbon number is 27 or more, and the HLB value is 10 or more, and if this is not satisfied, the ink intended for the purpose of the present invention must be It cannot be washed with water.

Specific examples of monohydric alcohols represented by the above general formulas [I] and -maximum [11] include POE (9) lauryl ether, POE (21) lauryl ether, POE
(25> lauryl ether, POE (5,5) cetyl ether, POE (7) cetyl ether, POE (10
) cetyl ether, POE (15) cetyl ether, P
OE (23) cetyl ether, POE (30) cetyl ether, P OE (40) cetyl ether, POE (
20) Stearyl ether, POE (7), oleyl ether, POE (15) oleyl ether,
POE <50) oleyl ether, POE (10) behenyl ether, POE (20> behenyl ether,
POE (30) Behenyl ether, POE (7) Secondary alkyl (15 carbon atoms) ether, POE (9) Secondary alkyl (15 carbon atoms) ether, POE (12>
Secondary alkyl (15 carbon atoms) ether, POE (7,
5) Nonylphenyl ether, P OE (15) /
Neil7 x Neil:X,, -f, POE (20)
Nonylphenyl ether, POE (10) octylphenyl ether, POE (30) octylphenyl ether, POE (10) monostearate, POE (25)
monostearate, POE (40) monostearate,
Examples include POE (55) monostearate and POE (10) monooleate. (Please note that POE is
Polyoxyethylene, the inside box indicates the amount added,
) Here, the amount of the above compound used must be in the range of 3% to 60% (equivalent ratio of hydroxyl groups) in the alcohol component (A), and if it is less than 3%, it is used for aqueous overprinting. No substantial suitability for varnish is observed, and on the contrary, if it exceeds 60%, synthesis of polyester resin becomes difficult.

Further, as other alcohols, pentyl alcohol, octyl alcohol, dodecyl alcohol, etc. can also be used.

On the other hand, polyhydric carboxylic acids of the carboxylic acid component (B) include adipic acid, pimelic acid, speric acid, fumaric acid, maleic anhydride, isophthalic acid, terephthalic acid, phthalic anhydride, trimetic anhydride, pyromellitic anhydride, etc. can be given.

In addition, some carboxylic acids may be used if necessary, and examples include fatty acids such as lauric acid, valmitic acid, stearic acid, oleic acid, and lylunic acid.

To synthesize a polyester resin from the alcohol component and the carboxylic acid component, it can be synthesized by a conventional method.For example, the above components are mixed in a nitrogen atmosphere at a concentration of 140-2
By heating in the range of 50°C, removing the water produced, and reacting at home to a predetermined acid value for 3 to 6 hours,
The desired polyester resin can be synthesized.

Further, although there is no particular restriction on the molecular weight of the polyester resin according to the present invention, a weight average molecular weight of 5.000 or more is desirable.

Next, the printing ink composition for metal will be described. The printing ink for metals is mainly composed of pigments, resins, and solvents, but the printing ink composition for metals according to claim 2 needs to contain the specified polyester resin by weight of 506 or more, When the amount is less than 1% by weight, the effects of suitability for aqueous overprint varnish and water washability, which are the objectives of the present invention, are not observed.

Other resins in the printing ink according to the present invention include various resins conventionally used in printing inks for metals.
It can be used in combination with the specified polyester resin, and there are no particular restrictions.Solvents include alkylene glycols having 2 to 8 carbon atoms, mono- and dialkyl ethers of these glycols, or alkylene oxides thereof. Examples include polyalkylene oxide adducts of monocarboxylic acids, and alkylene oxide adducts of monohydric alcohols. Examples of the curing agent include melamine resin and benzoguanamine resin.

As pigments, customary inorganic and organic pigments can be used.

You can also use a hair dryer, hooks, etc. if necessary.

In order to produce the printing ink according to the present invention from the above-mentioned materials, the following steps are required: 10 to 60% by weight of polyester resin and resin, 5 to 60% by weight of pigment, 10 to 50% by weight of solvent, and 0 to 30% by weight of curing agent. It can be produced by a conventional method.

Furthermore, as the water-based overprint varnish to be applied on top of the metal printing ink, conventionally used varnishes can be used. Specifically, water-based acrylic resins, water-based polyester resins, water-based alkyd resins, etc. An example is one in which an amino resin is used as a binder and a curing agent.

When printing on a metal material using the printing ink and aqueous overprint varnish having the above composition according to the present invention, it is usually carried out by a dry offset printing method or an offset printing method using dampening water, and further, after printing,
Overcoating is performed using a coater or the like with an aqueous overprint varnish, and then baking is performed at 130 to 200° C. for several minutes to more than ten minutes.

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited thereto.

<Example> 1 precept jLL C+sHs+O (CH2CH20) o H Niccol BT-9, manufactured by Nikko Chemicals ■, HLB value 13.5, total carbon number 33) 201.0 parts, trimellitic anhydride 71
．． 5 parts were charged in a Kolben and reacted at 170° C. for about 3 hours in a nitrogen atmosphere to obtain a monoester of trimellitic acid. Next, 20.7 parts of neopentyl glycol and 36.8 parts of trimethylolpropane were added, and the mixture was further heated at 220°C for about 3 parts.
Performed time reaction condensation, acid value 20, weight average molecular weight 113
, 000 polyester resin l was obtained, and the ratio of the carboxylic acid component (B) to the alcohol component (A) was approximately]:
1.4 (equivalent ratio), and the equivalent weight of the compound specified by general formula [1] in alcohol component (A) is about 21%.

Synthesis Example 2 C+uIzxC-0 (CH2CH20) roH (Niracol MYL-10, manufactured by Nikko Chemicals ■, HLB value 12
．． 5. Total carbon number 32) 203.4 parts and anhydrous Trimerit M 70.5 parts were charged in a Kolben, and 1
The reaction is carried out at 70°C for about 3 hours to obtain a monoester of trimellitic acid. Then, 23.3 parts of neopentyl glycol and 34.5 parts of trimethylolpropane were added to obtain Synthesis Example 1.
The reaction was carried out in the same manner as above, and the acid value was 20 and the weight average molecular weight was 2.
], 000 polyester resin 2 was obtained.

The ratio of carboxylic acid component (B) to alcohol component (A) is approximately 1.4 (equivalent ratio), and the equivalent of the compound specified by general formula [I] in alcohol component (A) is approximately 2.
It is 1%.

"Kin 1 Haru" - Niracol BT-9, 49, 5 parts used in Synthesis Example 1,
99.6 parts of neopentyl glycol, 34.1 parts of trimethylolpropane, 77.7 parts of adipine r1i, and 89.1 parts of isophthalic acid were charged in a Kolben, and an esterification reaction was carried out at 220°C for about 3 hours in a nitrogen atmosphere. Value 2
0, polyester resin 3 with a weight average molecular weight of 12.000
I got it. The ratio of the carboxylic acid component (B) to the alcohol component (A) is 1:1.3 (equivalent ratio), and the equivalent of the compound specified by the general formula [I] in the alcohol component (A>) is approximately 3%. be.

Synthesis example 4 H17C8-C6H4-0-(CH2CH20) r
oH Nikkor op-io, manufactured by Nikko Chemicals ■, HL
B value 11.5, total carbon number 34 > 208.0 parts,
715 parts of trimellitic anhydride was charged into a Kolben and reacted in a nitrogen atmosphere at 170°C for about 3 hours to obtain a monoester of trimellitic acid. Next, 20.7 parts of neopentyl glycol and 36.8 parts of trimethylolpropane were added and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain polyester resin 4 having an acid value of 20 and a weight average molecular weight of 16.000. In addition, carboxylic acid component (B) and alcohol component (A)
The ratio is about 1:1.4 (equivalent ratio), and the equivalent amount of the f-hybrid compound specified by general formula [I] in the alcohol component (A) is about 21%.

Synthesis Example 5 C+68i30- (CH2CH20)s, s H is Tucor BC-5,5, manufactured by Nikko Chemicals ■, HLB value 1
0.0, total carbon number 27) and 71.5 parts of trimellitic anhydride were charged into a Kolben and reacted at 170° C. for about 3 hours in a nitrogen atmosphere to obtain a monoester of trimellitic acid. Then neopentyl glycol 20.7
1 part, and 36.8 parts of trimethylolpropane were added, and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain an acid value of 20 and a weight average molecular weight of 1.
15,000 polyester resin 5 was obtained.

The ratio of carboxylic acid component (B) to alcohol component (A) is approximately 1:1.4 <equivalent ratio), and the alcohol component (
The equivalent weight of the compound specified by general formula [1] in A) is approximately 21
%.

Button [Mackerel L C + zHgqO (CH2CH20) 2q11 Sokol BL-25, manufactured by Nikko Chemicals ■, l-f L B value 1, 5, total carbon number 62) 414.1 parts, trimellitic anhydride 71.5 parts The mixture was charged into a Kolben and reacted at 170°C for about 3 hours in a nitrogen atmosphere to obtain a monoester of trimellitic acid. Next, neopentyl glycol 20.
7 parts and 36.8 parts of trimethylolpropane were added, and the reaction was carried out in the same manner as in Synthesis Example 1, and the acid value was 20. Polyester resin 6 having a weight average molecular weight j of 129.000 was obtained.

The ratio of carboxylic acid component (B) to alcohol component (A> is approximately 1:1.4 (equivalent ratio), alcohol component (
The equivalent weight of the compound specified by general formula [I] in A) is approximately 21
%.

Synthesis Example 7 I Cl7H3S CO(CH2CH20)4 (IH Niccol MYS-40, manufactured by Nikko Chemicals ■, HLB value 1
7.5, total carbon number 98) 658.2 parts and 71.5 parts of anhydrous trimellit M were charged in a Kolben and reacted at 170°C for about 3 hours in a nitrogen atmosphere to obtain a monoester of trimellitic acid9. 20.7 parts of pentyl glycol and 36.8 parts of trimethylolpropane were added and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain polyester resin 7 having an acid value of 20 and a weight average molecular weight of 43,000. The ratio of the carboxylic acid component (B) to the alcohol component (A) is approximately 1.1, 4 (equivalent ratio), and the equivalent of the compound specified by the general formula [■] in the alcohol component (A) is approximately 21%. It is.

1 liter of "Ruso" 119.7 parts of neopentyl glycol, 32.0 parts of trimethylolpropane, 92.3 parts of adipic acid, 106.0 parts of isophthalic acid and 30 parts of xylene were charged in a Kolben and heated to 220°C in a nitrogen atmosphere. The esterification reaction was carried out for about 6 hours, and when the acid value reached 10, xylene was distilled off to obtain a polyester resin having a weight average molecular weight of 113,000.

In addition, the ratio of the carboxylic acid component (B) and the alcohol component (A) is 1.1.2 (equivalent ratio), and the amount of the compound specified by the general formula [I] and [I[] in the alcohol component (A). teeth,
It is 0%.

A comparative polyester resin 1 having a solid content of 80% was prepared by dissolving this resin in hexyl alcohol with an adduct of 6 moles of propylene oxide.

L1 button (Mackerel L C18H370 (CH2CH20) 4 H to Kkkor B
5-4, manufactured by Nikko Chemicals ■, HLB value 9.0, total carbon number 26 > 143.6 parts, trimellitic anhydride 71.
Pour 5 parts into a Kolben and heat at 170°C in a nitrogen atmosphere.
After a period of reaction, a monoester of trimellitic acid is obtained.

Next, 20.7 parts of neopentyl glycol and 368 parts of 1-limethylolpropane were added and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain Comparative Polyester Resin 2 having an acid value of 20 and a weight average molecular weight of 14,000. The ratio of carboxylic acid component CB) to alcohol component (A) is approximately 1.4.
(equivalent ratio), general formula [1] in alcohol component (A)
This is the compound to be identified with! is approximately 21°. It is.

Dial direct judgment - λy CH2<CHs)C16Hs□OH, instearyl alcohol (Fine Oxocol 180, manufactured by Nissan Kaji) 157.0 parts, trimellitic anhydride 82.7 parts,
Charge 15 parts of xylene into a Kolben, and add 1 part of xylene in a nitrogen atmosphere.
The reaction is carried out at 70°C for 3 hours to obtain trimellitic acid monoester. Next, 110 parts of trimethylolpropane was added, the temperature was raised to 220°C, dehydration was carried out for 5 hours, and when the acid value reached 8, xylene was distilled off and the weight average molecular weight was compared at 3400. Polyester resin 3 was obtained. In addition, carboxylic acid component (B) and alcohol component (
The ratio of A) is about 1:2.4 <equivalent ratio), and the proportion of the compound specified by the general formula [N and [■]] in the alcohol component (A) is 0%.

``Uronoko'' 1 Blood Applicable □ Polyester Resin 1-7 and Comparative Polyester Resin 1-
30 parts by weight of each of 3 and 50 parts by weight of titanium oxide were mixed and dispersed in a conventional manner, followed by 10 parts by weight of melamine resin (Cymel 303, manufactured by Mitsui Toatsu Chemical Co., Ltd.) as a hardening agent and hexyl alcohol as a solvent component. A metal printing ink having a plastic viscosity of 100 to 200 voids was prepared by adding 10 parts by weight of the propylenoxide adduct.

Inks using each polyester resin were designated as Inks 1 to 7 and Comparative Inks 1 to 3, respectively.

Evaluation method 1) Compatibility test with water-based overprint varnish.

Approximately 3 o 11 g/100 c of inks 1 to 7 and comparative inks 1 to 3 were spread on an aluminum plate using an RI color spreader (manufactured by Mei Seisakusho).
After that, using a coater (manufactured by Toyo Seiki Co., Ltd.), apply an aqueous overprint varnish with the following composition (approximately 50 mg/100 mg in terms of solid content) using a wet-on-wet method. -) B. Baking was performed at 200° C. for 2 minutes in a gas oven to form a hardened film, and the repellency and smoothness of the surface were observed. The water-based overprint varnish used had the following composition.

[Composition of aqueous overprint varnish] Charge 40 parts of isopropyl alcohol and 25 parts of butyl cellosolve into a four-loaf flask, and while stirring while introducing nitrogen gas, maintain the temperature at 95°C and add 10 parts of styrene and 60 parts of butyl acrylate from the dropping tank. A mixture of 20 parts of methacrylic acid, 10 parts of hydroxyethyl acrylate, and 3 parts of benzoyl peroxygen was added dropwise over 3 hours. Thereafter, the temperature was maintained at 95°C, and the mixture was reacted for 2 hours, and then cooled. When the liquid temperature became 40°C or lower, 23.5 parts of triethylamine and 17 parts of water were added.
0 parts was added and the solvent was flowed out together with water under reduced pressure at 80"C to obtain an aqueous acrylic resin solution (A) with a solid content of 40% and a residual butyl cellosolve of 10%. This aqueous acrylic resin solution (A) 75 part, hexamethoxymelamine 15
part, amine-blocked paratoluene sulfo 260.2
1 part, 0.1 part and 7.2 parts of a silicone leveling agent, and 2.5 parts of butyl cellosolve to prepare an aqueous overprint varnish.

2) Cleanability with Water Test Inks 1 to 7 and Comparative Inks 1 to 3 are sufficiently kneaded between rolls using an RI color spreader. Then pour 30ml of water onto the roll.
cc was dropped and wiped off with a cloth to evaluate the cleanability with water.

The results of the above evaluation are shown in Table-1.

Table-1 The evaluation criteria are as follows.

1) Compatibility with water-based OP varnish: ◎: compatibility with water-based OP varnish, with no repellency observed at all and good gloss; ◎: compatibility with water-based OP varnish: ◎, with almost no repellency, but slightly reduced gloss; Those that can be seen are evaluated as △, and those that are repelled and the varnish is significantly engraved are evaluated as ×.

2) Washability test with water: If the ink can be wiped off well with dropped water, it is evaluated as ○, if it is not wiped off very well, it is △, and if it cannot be wiped off at all, it is evaluated as ×.

Effect> As shown above in Examples, the metal printing ink using the polyester resin specified in the present invention as a binder has sufficient suitability for water-based overprint varnish, and is free from the misting phenomenon. In addition to being characterized by the fact that it hardly ever occurs, it is also washable with water.

Therefore, when the metal printing ink according to the present invention is used, there is no need to use organic solvents not only for organic solvent-type overprint varnishes but also for ink cleaning work, which greatly improves the working environment. is possible.

Claims (2)

[Claims] (1) Polyester obtained by reacting an alcohol component (A) consisting of a polyhydric alcohol and a monohydric alcohol with a carboxylic acid component (B) consisting of a polyhydric carboxylic acid and, if necessary, a monohydric carboxylic acid. In the resin, the ratio of the alcohol component (A) to the carboxylic acid component (B) is from 1:1.1 to 1:2.5 (equivalent ratio), and from 3% to 60% in the alcohol component (A). % (equivalent ratio)
is a polyoxyethylene ether represented by the following general formula [I] and/or a polyoxyethylene ester represented by the general formula [II] having an HLB value of 10 or more. R_1-O-(CH_2CH_2O)_nH...General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...General formula [II] However, in the general formulas [I] and [II], R_1 is carbon An alkyl group, an alkenyl group, or an aryl group that may have 8 to 26 side chains, R_2
represents an alkyl group or alkenyl group which may have a side chain having 8 to 26 carbon atoms, n is a real number in the range of 3 to 70, and the total number of carbon atoms is 27 or more. (2) A printing ink composition for metals containing resin, pigment, and solvent as main components, which contains the polyester resin of claim 1 in an amount of 5% by weight or more in the printing ink.