JPS6228832B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to aqueous printing inks. More specifically, the present invention relates to a water-based printing ink that has excellent adhesion and water resistance to plastic films such as polyester films and vinyl chloride films, and metals such as aluminum, copper, and iron. Conventionally, many printing inks have been used that contain aromatic organic solvents, but in recent years,
From the viewpoint of air pollution and resource conservation, water-based printing inks that do not use such solvents have been proposed. The performance of such water-based inks depends mainly on the characteristics of the binder, which is its main component, and acrylic resins and alkyd resins having carboxyl groups have been proposed and put into practical use as binders for use in water-based printing inks. There is. However, many of these products do not have sufficient adhesion to polyester films or metals, and the use of a primer is essential.In order to simplify and speed up printing, it is possible to print directly onto ester films or metals without a primer. There is a strong demand for binders that have excellent adhesion and water resistance. On the other hand, attempts to water-solubilize or water-disperse polyester resins have been proposed, for example, in Japanese Patent Publication No. 47-40873 and Japanese Patent Application Laid-open No. 121336-1982, but all of them contain polyester or polyethylene glycol and are hydrophilic. Because of its strong properties, when used as a binder for printing ink, the printed surface easily blocks due to moisture absorption, making it difficult to use as a binder for printing ink. The inventors of the present invention have conducted extensive research to meet the needs of the industry, and have developed a film that has excellent adhesion to polyester films, metals, etc. without the need for a primer, and has excellent photo-selectivity, anti-blocking properties, and water resistance. The inventors discovered a binder for water-based printing ink and arrived at the present invention. That is, in the present invention, the dicarboxylic acid component is 2 to 20 mol% of an aromatic dicarboxylic acid containing a sulfonic acid metal group, 98 to 50 mol% of an aromatic dicarboxylic acid that does not contain a sulfonic acid metal group, and an aliphatic dicarboxylic acid having 4 to 36 carbon atoms. Acid and/or alicyclic dicarboxylic acid 0
~30 mol%, glycol component has 2 carbon atoms
-8 aliphatic glycol and/or alicyclic glycol 20-100 mol% and bisphenol A
This is an aqueous printing ink characterized by dispersing a polyester resin consisting of 80 to 0 mol% of an ethylene oxide or propylene oxide adduct and a pigment in a mixed medium of water and an organic compound compatible with water. . In the present invention, by dispersing a polyester resin containing a sulfonic acid metal base together with a pigment in a mixed medium of water and an organic compound that is compatible with water, it has excellent adhesion to polyester films, metals, etc. without the need for a primer. Furthermore, a water-based printing ink with excellent gloss, blocking resistance, and water resistance can be obtained. Examples of the aromatic dicarboxylic acid containing a sulfonic acid metal group in the polyester resin used in the present invention include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-
Sulfophthalic acid, 4-sulfonaphthalene-2,7
-Dicarboxylic acid-5[4-sulfophenoxy]isophthalic acid and other metal salts can be mentioned. Examples of metal salts include salts of Li, Na, K, Mg, Ca, Cu, Fe, and the like. Particularly preferred are 5
- Sodium sulfoisophthalate. Examples of the aromatic dicarboxylic acid containing no sulfonic acid metal group in the polyester resin used in the present invention include terephthalic acid, isophthalic acid, orthophthalic acid, and 2,6-naphthalenedicarboxylic acid. Aliphatic dicarboxylic acids having 4 to 36 carbon atoms include succinic acid, adipic acid,
azelaic acid, sebacic acid, dodecanedioic acid,
Examples of the alicyclic dicarboxylic acid include hexahydrophthalic acid, hexahydroisophthalic acid, and hexahydroterephthalic acid. Furthermore, if necessary, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid and their ester-forming derivatives, or hydroxycarboxylic acids or cyclic esters such as γ-butyrolactone and ε-caprolactone are added to the total acid components by 10%. It may be used within a range of less than mol%. Examples of the aliphatic glycol having 2 to 8 carbon atoms in the polyester resin used in the present invention include ethylene glycol, propylene glycol, 1.3
-propanediol, 1,4-butanediol,
These include neopentyl glycol, 1,5-pentanediol, and 1,6-hexanediol. Examples of the alicyclic glycol include 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol. As the ethylene oxide or propylene oxide adduct of bisphenol A of the polyester resin used in the present invention, bisphenol
Examples include glycols to which 2 to 10 moles of ethylene oxide or propylene oxide are added per mole of A. The use of polyether glycols such as diethylene glycol and polyethylene glycol is undesirable because it reduces water resistance and blocking resistance, but it may be used within the allowable range, that is, 10% by weight or less based on the total glycol. Good too. The polyester resin used in the present invention has a dicarboxylic acid component of 2 to 20 mol% of an aromatic dicarboxylic acid containing a sulfonic acid metal group, 98 to 50 mol% of an aromatic dicarboxylic acid that does not contain a sulfonic acid metal group, and a carbon number of 4 to 36. It consists of 0 to 30 mol% of aliphatic dicarboxylic acid and/or alicyclic dicarboxylic acid. 2 mol% of aromatic dicarboxylic acid containing sulfonic acid metal base
If the amount is less than 1, the polyester resin cannot be uniformly dispersed in water or a mixed medium of water and an organic solvent that is compatible with water. On the other hand, if it exceeds 20 mol %, the adhesion of the resulting printing ink to the polyester film decreases, making it impractical. Furthermore, if the aromatic dicarboxylic acid that does not contain a sulfonic acid metal base is less than 50 mol% and the aliphatic dicarboxylic acid and/or alicyclic dicarboxylic acid exceeds 30 mol%, the blocking resistance of the resulting printing ink will deteriorate. , water resistance also decreases. The polyester resin used in the present invention has a glycol component consisting of 20 to 100 mol% of aliphatic glycol and/or alicyclic glycol having 2 to 8 carbon atoms and 80 to 0 mol% of an ethylene oxide or propylene oxide adduct of bisphenol A. Become. When the aliphatic glycol and/or alicyclic glycol is less than 20 mol% and the ethylene oxide or propylene oxide adduct of bisphenol A exceeds 80 mol%, the polymerizability of the polyester decreases, and the polyester film of the resulting printing ink deteriorates. Adhesion to the surface decreases. The polyester resin used in the present invention is essentially amorphous and has a softening point in the range of 100 to 200°C. If the softening point is less than 100°C, the printing ink obtained will cause blocking and will be of no practical use.On the other hand, if the softening point exceeds 200°C, the polyester resin will have poor dispersibility in water. The molecular weight of the polyester resin used in the present invention is preferably in the range of 600 to 30,000. However, when producing printing ink mainly using a single polyester resin, it is preferable to use one with a molecular weight in the range of 5,000 to 20,000, and if necessary, two or more types of polyester resins may be mixed and used according to the required properties. can. In the case of a polyester resin having a molecular weight exceeding 30,000, the viscosity of the dispersion after being dispersed in water becomes high, making it difficult to increase the concentration of the polyester resin. On the other hand, if the molecular weight is less than 600, the binder itself has poor cohesive force, and the ink may block or be brittle, resulting in poor film-forming properties and cannot be put to practical use. When a polyester resin with a molecular weight in the range of 600 to 5000 is used alone as a binder for printing ink, the performance of the ink such as blocking resistance and water resistance is somewhat low, so it should be used in combination with a polyester resin with a higher molecular weight. is desirable. In the present invention, a polyester resin is uniformly dispersed in water in the presence of an organic compound that is compatible with water. The mixing ratio of water and an organic compound compatible with water is preferably 20 to 99/80 to 1 by weight. The proportion of organic compounds that are compatible with water is 1
If the amount is less than 80% by weight, or even if it exceeds 80% by weight, the resulting aqueous dispersion will have poor storage stability. Organic compounds that are compatible with water have a boiling point of 60 to 200.
℃ and dissolves at least 20 parts by weight per 100 parts by weight of water at 20°C, such as methanol, ethanol, n-propanol, isopropanol,
n-butanol, i-butanol, sec-butanol, tert-butanol, ethylene glycol,
Propylene glycol, methyl cellosolve, ethyl cellosolve, n-propyl cellosolve, i-propyl cellosolve, n-butyl cellosolve, tert
-Butyl cellosolve, 3-methyl-3methoxybutanol, n-butyl cellosolve acetate, dioxane, tetrahydrofuran, ethyl acetate,
Examples include methyl ethyl ketone and cyclohexanone. These compounds may be used alone or in combination of two or more. Most preferred among these compounds is isopropanol. A method for uniformly dispersing the polyester resin of the present invention in water is to add the polyester resin to a mixed medium of water and an organic compound that is compatible with water at a temperature below the boiling point of the organic compound that is compatible with water. ,
A method of dispersing the polyester resin uniformly under stirring, a method of dissolving the polyester resin in an organic compound that is compatible with water at a temperature below the boiling point of the organic compound, and then gradually adding water under stirring, or vice versa. ,
There are methods such as mixing a polyester resin solution into water while stirring, but the most suitable method can be selected depending on the need. The concentration of the polyester resin in the resulting aqueous dispersion is 5 to 60% by weight, preferably 10 to 40% by weight; if it is less than 5% by weight, the aqueous printing ink will have poor adhesion to the surface of the polyester film, and vice versa. to 60
If it exceeds % by weight, the viscosity of the aqueous dispersion becomes too high and printing becomes impossible. The aqueous printing ink binder made of the above aqueous dispersion can be used in combination with a well-known aqueous printing ink binder such as an aqueous solution or dispersion of an alkyd resin, an epoxy resin, a rosin resin, a styrene-acrylic resin, an acrylic resin, etc. You may. The aqueous printing ink of the present invention is made by dispersing a pigment in the above aqueous dispersion. Pigments used in the present invention include white pigments such as titanium oxide, zinc white, lead white, black pigments such as carbon black, pine smoke (lamp black), and graphite, and gray pigments such as zinc powder, zinc oxide, and slate powder. , cadmium red, cadmium mercury red,
Red pigments such as red iron, cadmium yellow, zinc yellow,
Yellow pigments such as yellow lead and titanium yellow, green pigments such as viridian, chromium oxide green, cobalt green, and chromium green, blue pigments such as ultramarine, deep blue, and cobalt blue, purple pigments such as manganese purple, cobalt purple, mars yellow, Iron oxide pigments such as iron oxide black, extender pigments such as calcium carbonate, barium sulfate, alumina, talc, clay, Permanent Red 4R, Hansa Yellow G, Hansa Yellow 10G, Brilliant Carmine 3B, Brilliant Carmine
These include azo organic pigments such as 6B, phthalocyanine organic pigments such as Phthalocyanine Green and Fast Sky Blue, metal powder pigments such as silver powder, copper powder, and gold powder, glass powder, glass flakes, and glass beads. The blending ratio of pigment and polyester resin is 50-2:50-98 (weight ratio). If the amount of pigment exceeds 50% by weight based on the total amount of pigment and polyester resin, dispersibility will be poor.
If it is less than 2% by weight, the coloring properties will be poor. The water-based printing ink of the present invention may contain, if necessary, acrylic additives known as surface smoothing agents and antifoaming agents, such as Modaflow (manufactured by Monsanto) and Polyflow S (manufactured by Kyoeisha Yushi Chemical), and silicone additives, such as Bisilon. OL (manufactured by Bayer), YF
−3818, XF-3913, TSA-720 (manufactured by Toshiba Silicone), etc. can be added. Furthermore, melamine resins, acrylic resins, epoxy resins, phenoxy resins, polyurethane resins, polystyrene, polybutadiene, polyvinyl chloride, polyethylene, polypropylene, polyvinyl acetate, ethylene-vinyl acetate copolymers, within a range that does not impair the purpose of the present invention. , styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-
It is also possible to blend maleic anhydride copolymers, butadiene-maleic anhydride copolymers, polyester resins containing no sulfonic acid metal bases, and the like. The water-based printing ink of the present invention not only has extremely excellent adhesion to various plastic films, paper, metals, textile fabrics, etc., but also has excellent water resistance, blocking resistance, and flexibility, and is superior to conventional water-based printing inks. It has characteristics that cannot be demonstrated by other methods. EXAMPLES Examples are given below to explain the present invention more specifically, but the present invention is of course not limited to the Examples in any way. In the examples, parts simply indicate parts by weight. Various measurements were made according to the following methods. (1) Molecular weight Molecular weight measuring device (manufactured by Hitachi,
115 type) was used for measurement. (2) Softening point Fully automatic melting point measuring device (METTLER)
The measurement was carried out using MODEL FP-1) manufactured by Co., Ltd. (3) Adhesion Compliant with ASTMD-3359. (4) Blocking resistance Evaluated by touch with finger. (5) Optical gloss meter (Nippon Denshoku Kogyo TYPE-
VG107). Production example 1 466 parts of dimethyl terephthalate, 388 parts of dimethyl isophthalate, 178 parts of dimethyl 5-sodium sulfoisophthalate, 443 parts of ethylene glycol
parts, 400 parts of neopentyl glycol, zinc acetate
A reaction vessel was charged with 0.44 parts of sodium acetate, 0.04 parts of sodium acetate, and 0.43 parts of antimony trioxide, and a transesterification reaction was carried out at 140 to 220°C over 4 hours. Next 1
The pressure inside the reaction system was reduced to 1 mmHg over time, and 260
The polycondensation reaction was carried out under vacuum at 0.1 to 0.2 mmHg for 1 hour. The obtained polyester resin (A-1) had a molecular weight of 18,000 and a softening point of 162°C. Composition analysis of polyester resin (A-1) by NMR etc. revealed that 48 mol% of terephthalic acid and 40% of isophthalic acid were found.
The mol% was 12 mol% of 5-sodium sulfoisophthalic acid, 48 mol% of ethylene glycol, and 52 mol% of neopentyl glycol. Furthermore, polyester resin (A
-2) to (A-8) were obtained. Their characteristic values are shown in Table 1.

【table】

[Table] Example 1 Add 30 parts of polyester resin (A-1) to a mixed solution of 14 parts of isopropanol and 56 parts of water,
A binder for water-based printing ink was obtained by uniformly dispersing the mixture for 3 hours under heating at .degree. After cooling, the particle size of the dispersion was measured and was found to be less than 1 μm, with a diameter of 1 μm at 0°C.
Storage stability was measured for months, but the dispersion state did not change. Next, 100 parts of the above aqueous dispersion with a solid content of 30%, 15 parts of titanium oxide [manufactured by Ishihara Sangyo Co., Ltd.: R-930], and silicone compound XF-3913 [Toshiba Silicone
0.5 part of a 50% by weight ethanol solution (manufactured by Co., Ltd.) was added, stirred and mixed, and further mixed uniformly using a ball mill to prepare a white water-based ink. This water-based printing ink was coated onto a 125μ polyethylene terephthalate film using a bar coater #20 to a film thickness of 7.
After applying it so that it becomes μ and drying it for 2 minutes at 70℃,
When the coated surface was judged by touch, no blocking property was observed. The results of water resistance and adhesion tests were also good as shown in Table 2. Examples 2 to 4 A binder for water-based printing ink was prepared using polyester resin (A-2) and polyester resin (A-3) under the compounding conditions shown in Table 2 in the same manner as in Example 1, and the binder was carried out. A white water-based printing ink was prepared in the same manner as in Example 1. It was coated on a 125μ polyethylene terephthalate film and tested for blocking resistance, water resistance, and adhesion, and as shown in Table 2, good results were obtained. Comparative Examples 1 to 5 A binder for water-based printing ink was created using polyester resins (A-4) to (A-8) in the same manner as in Example 1, and white water-based printing was performed in the same manner as in Example 1. Created ink. Table 2 shows the results of coating on a 125μ polyethylene terephthalate film and evaluating its performance.

【table】

【table】

Claims (1)

[Claims] 1 The dicarboxylic acid component is 2 to 20 mol% of an aromatic dicarboxylic acid containing a sulfonic acid metal group, 98 to 50 mol% of an aromatic dicarboxylic acid that does not contain a sulfonic acid metal group, and an aliphatic dicarboxylic acid having 4 to 36 carbon atoms and/or or alicyclic dicarboxylic acid 0 to 30 mol%
The glycol component is an aliphatic glycol and/or alicyclic glycol having 2 to 8 carbon atoms.
~100 mol% and ethylene oxide or propylene oxide adducts of bisphenol A80
1. A water-based printing ink comprising a polyester resin and a pigment containing up to 0 mol % dispersed in a mixed medium of water and an organic compound compatible with water.