JP2001139864A - Additive for water-based ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive for a water-based ink imparting excellence in heat resistance and abrasion resistance to a water-based ink. SOLUTION: The additive for a water-based ink comprises an aqueous polyester dispersion composed mainly of a water-insoluble polyester (A), a polyester- based polymer (B) containing a sulfonate group bonded thereto and water (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous ink additive, and more particularly to an aqueous ink additive having excellent heat resistance and abrasion resistance.

[0002]

2. Description of the Related Art Water-based inks have come to be widely used for printing inks on cardboards and the like in place of conventional solvent-based inks from the viewpoints of environmental consideration and resource saving. Various improvements have been made in order to meet the physical property requirements of the intended use. Regarding the abrasion resistance particularly required for printing inks, a water-based ink containing a resin as a main component alone has low abrasion resistance, and therefore, abrasion resistance has been imparted by adding a wax or the like. Was.

However, in recent years, physical properties required for water-based inks have become more severe with changes in printing technology. For example, recently, printing by an offset rotary printing press has become widespread, and thus, printed materials have often been dried at high temperatures. As a result, it has been pointed out that, as an additive for an offset rotary ink, an aqueous dispersion of waxes conventionally used mainly has insufficient heat resistance, and does not exhibit sufficient abrasion resistance after drying at a high temperature. Have been. For water-based inks, further improvement of abrasion resistance and improvement of heat resistance are desired.

[0004]

[PROBLEMS TO BE SOLVED] To provide an additive for water-based ink which gives excellent heat resistance and abrasion resistance to the water-based ink.

[0005]

The present invention provides (A) a water-insoluble polyester, (B) a polyester polymer containing a sulfonate group bonded to a polymer, and (C) a polymer mainly containing water. An aqueous ink additive comprising a polyester aqueous dispersion comprising:

In the present invention, the content of the sulfonic acid salt group bonded to the polymer in the polyester polymer (B) is 0.1 in terms of —SO ₃ — group per gram of the polymer.
The aqueous ink additive having a concentration of 1 to 1.5 millimolar equivalent is a preferred embodiment.

The solubility parameter (Sp) of the water-insoluble polyester (A) and the polyester-based polymer (B) is
Is a preferred embodiment of the present invention, wherein the aqueous ink additive has a difference of 2 [cal / cm ³ ] ^1/2 or less.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in detail. The aqueous ink additive of the present invention comprises (A) a water-insoluble polyester, (B) a polyester polymer containing a sulfonate group bonded to a polymer, and (C) an aqueous polyester dispersion mainly comprising water. An aqueous ink additive comprising:

The above-mentioned water-insoluble polyester (A) is a polyester which does not uniformly dissolve, swell or disperse in water or hot water, and is an aromatic polyester, an aliphatic polyester, a saturated polyester, an unsaturated polyester, Including various types of polyester such as polyester.

The water-insoluble polyester used in the present invention is mainly a polycondensate of an acid component monomer and an alcohol component monomer. As the acid component, for example, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acids,
4,4′-diphenyldicarboxylic acid, trimellitic acid,
Trimesic acid, pyromellitic acid, benzoic acid, p-oxybenzoic acid, p- (hydroxyethoxy) benzoic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, suberic acid, brassic acid, dodecanedicarboxylic acid , Fumaric acid, maleic acid, itaconic acid, 1,4
-Cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, hexahydroorthophthalic acid, tricyclodecanedicarboxylic acid, tetrahydroterephthalic acid,
And tetrahydroorthophthalic acid, or a methyl ester or anhydride of these acids. Among these, terephthalic acid, isophthalic acid,
Adipic acid, sebacic acid and trimellitic anhydride are preferably used, and these acid components can be used alone or in combination of two or more.

As the alcohol component, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol,
1,4-butanediol, 1,2-butanediol,
1,5-pentanediol, 2-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 1,8-octanediol , 1,9-nonanediol, 1,10-decanediol, 2,2,4
Trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, bisphenol-ethylene oxide adduct, bisphenol-propylene oxide adduct, 1, 4-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclohexanedimethanol, 1,3-cyclohexanediol, hydrogenated bisphenol A, spiroglycol, tricyclodecanediol, tricyclodecanedimethanol, resorcinol and the like Ethylene glycol ether and the like are used, among which ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butane Ol, neopentyl glycol are preferably used, these alcohol components alone,
Alternatively, a plurality of combinations can be used.

The polyester polymer (B) used in the present invention is also a polycondensate of an acid component monomer and an alcohol component monomer. In addition to the acid and alcohol components used in the water-insoluble polyester, 5-sulfoisophthalic acid, sulfoterephthalic acid,
-Sulfophthalic acid, 5- (p-sulfophenoxy) isophthalic acid, 5- (sulfopropoxy) isophthalic acid, 4
-Sulfonaphthalene-2,7-dicarboxylic acid, sulfopropylmalonic acid, sulfosuccinic acid, 2-sulfobenzoic acid, 3-sulfobenzoic acid, 5-sulfosalicylic acid, methyl esters of these carboxylic acids, and metals of these sulfonic acids Salts and ammonium salts are used, among which sodium salt of 5-sulfoisophthalic acid and 5-
The sodium salt of dimethyl sulfoisophthalate is preferably used.

[0012] These sulfonic acid-containing components can be used as the polyester polymer (B) in view of the hygroscopicity, water resistance, weather resistance, etc. of the fine particles obtained from the aqueous dispersion, or the phase inversion after addition of water. There polymer per gram of -SO ₃ - preferably contains a concentration of 0.1 to 1.5 mmol equivalents of base terms, still more preferably in a concentration of 0.2 to 1.0 mmol equivalents.

Further, the polyester system used in the present invention
The polymer (B) is a water-insoluble polyester of interest
It is preferable to select one having good compatibility with (A).
Good. For example, aromatic water-insoluble polyester (A)
Is an aromatic polyester with similar constituents
It is preferable to use the system polymer (B). Proper poly
It is one guide when choosing the ester polymer (B).
The index is the solubility parameter (Sp value). Ie
Water-insoluble polyester (A) and polyester polymer
The difference in solubility parameter from (B) is 2 [cal / cm^Three]^1/2
Within, especially 1 [cal / cm ^Three]^1/2More preferably within
The result is obtained.

In the present specification, the solubility parameter (Sp value) is a value defined in a usual meaning, that is, as a half power of the cohesive energy density. The solubility parameter is obtained by calculating the contribution value Vi of the group to the molar volume and the cohesion energy En of the group by DWVanKlevelen "Properties".
using the value according to of Polymers "(Elsevier, 1972) , is calculated from the equation ^{Sp = (ΣEni / ΣVi) 1} /2 [cal / cm 3] 1/2.

The aqueous polyester dispersion, which is the main component of the aqueous ink additive of the present invention, comprises a water-insoluble polyester (A) and a polyester polymer (B) satisfying the above requirements as main raw materials. Water or a basic aqueous solution equivalent to 1 to 40% by weight of the whole is added, and the mixture is further kneaded, whereby the resin melt can be obtained by inverting the phase to an aqueous dispersion. At this time, the addition amount of water or the basic aqueous solution is more preferably 15 to 30% by weight based on the whole.

The basic aqueous solution in the present invention includes the following substances which act as bases in water, for example, alkali metals, alkaline earth metals, ammonia and amines, alkali metal oxides, hydroxides, weak acid salts and hydrogen. Oxides, hydroxides, weak acid salts, hydrides and alkoxides of these metals. More specifically, sodium, potassium, calcium, strontium, barium, hydroxylamine, inorganic amines such as hydrazine, methylamine, ethylamine, ethanolamine, cyclohexylamine, sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, Strontium oxide, barium oxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium hydride, potassium hydride, calcium hydride, sodium carbonate, potassium carbonate, sodium bicarbonate, hydrogen bicarbonate Potassium, calcium hydrogen carbonate, sodium acetate, potassium acetate, calcium acetate, ammonium hydroxide, quaternary ammonium compounds such as tetramethylammonium hydroxide, hydrazine hydration And the like can be given.

The aqueous dispersion thus obtained is an apparent solid having a solid content of 60% by weight or more, and the solid content can be uniformly dispersed as fine particles in the aqueous phase by adding water. It is suitable. The solid content is more preferably 70% by weight or more.

The weight ratio of the water-insoluble polyester (A) / polyester polymer (B) used in the present invention is preferably from 95/5 to 50/50, and is preferably 90/1.
More preferably, it is 0 to 60/40.

In the present invention, the water dispersibility of the polyester resin can be improved by adding an anionic surfactant as necessary. For example, primary higher fatty acid salts, secondary higher fatty acid salts, primary higher alcohol sulfate salts, secondary higher alcohol sulfate salts, higher alkyl disulfonates, sulfonated higher fatty acid salts, higher fatty acid sulfate salts Higher fatty acid ester sulfonate, higher alcohol ether sulfate, higher alcohol ether sulfonate, higher fatty acid amide alkylolated sulfate, alkyl benzene sulfonate, alkyl phenol sulfonate, alkyl naphthalene sulfonate Any substance may be used as long as it reacts with a basic substance such as an alkylbenzimidazole sulfonate to become an anionic surfactant.

More specific compound names of these surfactants are, for example, “Synthetic surfactants” written by Hiroshi Horiguchi (Showa 41,
Sankyo Publishing). Of these, alkylbenzene sulfonates are particularly preferred, and more specifically, sodium dodecylbenzenesulfonate.

As a method of incorporating such a surfactant, the surfactant may be added as a raw material together with the water-insoluble polyester (A) and the polyester-based polymer (B), or may be prepared in advance as an aqueous solution and added during melt-kneading. May be. Further, the content is preferably 10% by weight or less, and more preferably 3% by weight or less, based on the whole aqueous polyester dispersion. When the surfactant is contained in an amount of 10% by weight or more, there is a problem that the fine particles obtained from the aqueous dispersion have high hygroscopicity, and the water resistance, weather resistance and the like are reduced.

By adding water to the aqueous dispersion of high solids polyester obtained in the present invention, the 50% volume average particle size of the solid particles uniformly dispersed in water is 0.1 to 1%.
It is preferably 0 μm, more preferably 0.2 to 5 μm.

The aqueous dispersion of high solids polyester obtained in the present invention can be converted into a liquid aqueous dispersion having fluidity by adding water or a basic aqueous solution (including hot water) as needed and stirring. Cooled naturally or artificially to room temperature.

As described above, by further finely dispersing the aqueous dispersion of the high solid content polyester uniformly and finely in water, it is possible to widely adjust the liquid properties such as the solid content concentration, viscosity, pH, etc. Can be added. The polyester resin prepared in such a desirable aqueous dispersion has excellent properties such as water resistance, weather resistance, processability, and adhesiveness, similarly to the original high solids polyester aqueous dispersion.

As the melt-kneading means which can be used in the production method of the present invention, any known method may be used, but preferred examples include a twin-screw extruder, a single-screw extruder, a kneader and a Banbury mixer.

The aqueous ink additive of the present invention may contain various auxiliary materials which can be used in the aqueous dispersion of the polyester, such as a dispersant and an emulsifier, as long as the performance is not impaired. Surfactants, stabilizers,
Wetting agent, thickening agent, foaming agent, antifoaming agent, coagulant, gelling agent,
Anti-settling agent, antistatic agent, antistatic agent, anti-aging agent, softener, plasticizer, filler, colorant, fragrance, anti-adhesive,
A release agent or the like may be used in combination.

The additive for aqueous ink of the present invention is added in the range of 0.1 to 10%, preferably 1 to 5%, based on the resin which is the main component of the aqueous ink.

The resin which is the main component of the water-based ink is not particularly limited, but is usually starch, dextrin, alginate, cellulose ester, cellulose ether, polyvinyl alcohol, polyvinyl methyl ether, polyacrylamide, polyethylene oxide. Water-soluble resin such as polyacrylate, shellac, styrenated shellac, styrene maleic acid resin, rosin maleic acid resin, casein and its derivatives, colloidal dispersion such as acrylic copolymer, acrylic resin, acrylic styrene copolymer Resin, vinyl acetate resin,
Emulsions such as styrene resin, vinyl chloride resin, synthetic rubber latex, polyurethane, polyester, alkyd resin, epoxy ester, and rosin ester can be used.

[0029]

EXAMPLES The present invention will be described in detail below with reference to preferred examples and comparative examples of the present invention, but these examples do not limit the scope of the present invention in any way.

In the present invention, various characteristic values were measured by the following methods. (1) Dispersion state of aqueous dispersion The dispersion was examined by passing the dispersion through a 100-mesh wire net. (2) Particle Size (μm) of Aqueous Dispersion A 50% volume average particle size was measured with Microtrac HRA (Microtrac). (3) pH of aqueous dispersion Measured with a pH meter (manufactured by HORIBA).

(4) Evaluation of abrasion resistance of water-based ink Base material on which water-based ink is printed: K liner paper (Oji Paper Co., Ltd.) White liner paper (Sets Co., Ltd.) Water-based ink: water-based varnish (Joncryl 62: Johnson Polymer), pigment dispersion (WS RED R-
1: Toyo Ink Manufacturing Co., Ltd.) and a binder (Joncry)
l 450) was mixed at a ratio of 20:40:40 to prepare an ink. Evaluation method for abrasion resistance: Ink is applied to the above substrate so as to have a dry film thickness of 3.4 μm. Gakushin-type friction tester type II (Tester Sangyo Co., Ltd.) used Friction paper CRC cardboard Load / number of times of friction 200 g x 500 times Evaluation The ink-coated surface is rubbed with a cardboard attached to a friction element, and the ink is applied to the cardboard. The degree of transfer is visually evaluated according to the following criteria and evaluated in five steps. 5: Ink is hardly transferred. 4: Ink is transferred to about 20% of the entire area. 3: The ink is transferred to about 50% of the entire area. 2: The ink is transferred to about 80% of the entire area. 1: Ink is transferred to almost the entire surface.

[Production Example (A) -1: water-insoluble polyester 1] 83 parts of terephthalic acid, 83 parts of isophthalic acid, 62 parts of ethylene glycol and 0.1 part of dibutyltin oxide were charged into a reaction vessel and gradually heated from 140 ° C. The transesterification was carried out for 6 hours while removing water generated up to 250 ° C. Next, a polycondensation reaction was carried out under reduced pressure for 2 hours while increasing the temperature from 250 ° C. to 280 ° C. to obtain a water-insoluble polyester (A) -1. Table 1 shows the composition and Sp value of the obtained polyester.

[Production Example (A) -2: water-insoluble polyester 2] 50 parts of terephthalic acid, 50 parts of isophthalic acid, 58 parts of adipic acid, 31 parts of ethylene glycol, 53 parts of diethylene glycol, and 0.1 part of dibutyltin oxide are reacted. The mixture was charged in a container and transesterification was carried out for 6 hours while removing water generated from 140 ° C. to 220 ° C. gradually. Next, the polycondensation reaction was performed under reduced pressure for 2 hours while increasing the temperature from 220 ° C. to 250 ° C., to obtain a water-insoluble polyester (A) -2. Table 1 shows the composition and Sp value of the obtained polyester.

[Production Examples (B) -1 to 3: Polyester Polymers 1 to 4] Instead of the monomers and monomer ratios used in Production Example (A) -1, the monomers and monomer ratios shown in Table 1 were used. And polyester polymers 1 to 5 were obtained in the same manner as in Production Example (A) -1. Composition of the obtained polyester, -SO ₃ -molar concentration in 1 g of resin and S
Table 1 shows the p values.

[Table 1]

[Synthesis Example 1] Water-insoluble polyester (A)
-1 and 50 parts of the polyester polymer (B) -2
Parts, a mixture of 1 part of sodium dodecylbenzenesulfonate as an anionic surfactant, at a rate of 101 parts / hour, a co-rotating twin-screw extruder (PCM-3 manufactured by Ikegai Iron Works)
0, L / D = 40), melt-knead at a set temperature of 240 ° C. and a screw rotation speed of 150 rpm, and continuously feed water at a rate of 25 parts / hour from a supply port provided in an intermediate portion of the extruder. Supplied. The mixture of extruded resin etc.
The mixture was cooled to 90 ° C. by passing through a single screw extruder installed at the outlet of the extruder, and discharged. The discharged material was a white solid, and the solid content concentration calculated from the difference in weight before and after drying was 77% by weight. When this aqueous dispersion was added to warm water, it was finely dispersed, and a white aqueous dispersion was obtained. The solid content was adjusted to 30% by weight, and the mixture was filtered through a 100-mesh wire net. However, no undispersed substance was observed and the dispersion state was good. Manufacturing conditions, solid content concentration, average particle size, p
H is described in Table 2.

[Synthesis Examples 2 and 3] Water-insoluble polyester,
An emulsion was obtained in the same manner as in Example 1, except that the polyester-based polymer and the emulsification conditions were changed to the conditions described in Table 2. The properties are shown in Table 2.

[Table 2]

[0037]

Example 1 The aqueous polyester dispersion synthesized in Synthesis Example 1 was added to the aqueous ink at a solid content ratio of 1%,
Stir to obtain a sample. This was applied to a K liner in accordance with the above-described method for evaluating abrasion resistance, dried at room temperature for 2 days, and then its abrasion resistance was evaluated. The results are shown in Table 3.

[0038]

Example 2 The same evaluation as in Example 1 was carried out except that the drying conditions were changed to 120 ° C. and 20 minutes, and the abrasion resistance was evaluated. The results are shown in Table 3.

[0039]

Examples 3-10 Polyester aqueous dispersions used
Except for changing the base material under the conditions described in Table 3, the same evaluation as in Example 1 was performed to evaluate the abrasion resistance. The results are shown in Table 3.

[0040]

Comparative Examples 1 to 10 Instead of the aqueous polyester dispersion, a polyethylene wax dispersion (Kemipearl W700, Mitsui Chemicals, Inc .: average particle size 1.2 μm, W4)
00: 3 μm, W308: 7 μm), and the same evaluation as in Example 1 was performed to evaluate abrasion resistance. The results are shown in Table 3.

[Table 3]

Claims (4)

[Claims] 1. An aqueous polyester dispersion mainly comprising (A) a water-insoluble polyester, (B) a polyester polymer containing a sulfonate group bonded to a polymer, and (C) water. Water-based ink additive. 2. The polyester-based polymer (B) has a sulfonate group content of 0.1 to 1.5 mmol equivalent per gram of the polymer in terms of --SO ₃ -groups per gram of the polymer. The aqueous ink additive according to claim 1, wherein the concentration is a concentration. 3. The method according to claim 1, wherein the difference between the solubility parameter (Sp value) of the water-insoluble polyester (A) and the polyester-based polymer (B) is 2 [cal / cm ³ ] ^1/2 or less. 3. The additive for aqueous ink according to 1 or 2. 4. The method according to claim 1, wherein the weight ratio of the water-insoluble polyester (A) / polyester polymer (B) in the aqueous polyester dispersion is 95/5 to 50/50. The aqueous ink additive according to any one of the above.