JPH0564669B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vehicle constituting an ultraviolet curable ink (hereinafter referred to as UV ink).Vehicles can be divided into those that are liquid in form and those that have gel elasticity, but the present invention relates to vehicles that have gel elasticity. vehicle (hereinafter referred to as gel varnish)
It is related to. The necessity and usefulness of gel varnishes have been described in various documents. For example, on page 183 of the Printing Ink Handbook published by the Printing Ink Industry Federation, ``Gel'' is described as ``Gel-like varnish is added to letterpress or lithographic inks to improve transferability to printing materials.''
It may be used to improve ink fluidity, emulsification resistance, etc. "a. Also, the patent application was published in 1982.
In 174667, regarding the necessity of UV ink gel varnish, ``The ink has appropriate viscosity and viscoelasticity,
This is absolutely necessary so that it does not change significantly depending on the printing environment or conditions such as printing temperature and amount of dampening water supplied. As described above, gel varnish is desired to be developed for UV ink.
For situations where this is difficult, please refer to the patent application announcement.
55-12446, ``For varnish preparations that require particular elasticity, solvent-based elastic gel varnishes that chelate resin, oil, and solvent systems with aluminum chelate are essential for adjusting the rheological properties of printing inks. However, in the case of self-curing UV-curable inks, solvent-free photopolymerizable varnishes are generally used as vehicle compositions; When synthesizing an elastic gel varnish that is compatible with polymerizable varnishes, it is extremely difficult to reach the level of conventional elastic gel varnishes.
It is stated that. However, as described above, the extremely difficult gel varnish technology can be taken one step further by providing hydroxyl groups, carboxyl groups, etc. as chemically active groups to the UV ink varnish, and allowing the active groups to react with metal alcoholates or their chelate compounds. Moved forward. For example, a photopolymerizable compound containing a hydroxyl group in Patent Application Publication No. 12446/1980, a photopolymerizable compound containing a carboxyl group in Patent Application Publication No. 54-60390, and a hydroxyl group value of 20-250 in Patent Application Publication No. 54-118499. This is rosin-modified unsaturated epoxy resin ester. However, such UV ink varnishes containing hydroxyl and carboxyl groups are themselves strongly emulsified by the dampening water used in lithographic printing, which is the mainstream of printing, and even after being made into gel varnishes, they still do not emulsify. The trend remains. That is, these gel varnishes are not suitable at least for enhancing emulsion resistance during wet lithographic printing. Furthermore, since printing ink is a mixture, it comes into contact with various other compounds. In particular, in UV inks, in addition to pigments, they come into contact with chemically sensitive compounds such as stabilizers and photosensitizers. ), which are undesirable as they impede quality maintenance over time. The present invention has been made to solve the problems of current UV ink gel varnishes as described above. In other words, it does not impair the properties that should be maintained as a vehicle for UV ink (UV curability, storage stability, ability to maintain the dispersion of pigments, etc.), and as a gel varnish it can be used as a UV ink with heat change resistance, dampening water resistance (emulsification resistance), and thixotropic properties. The purpose was to develop a gel varnish for UV ink that could impart properties. In order to achieve this objective, the present inventors have developed a gel varnish for UV ink using a UV ink varnish instead of the conventional method of introducing active groups such as hydroxyl groups and carboxyl groups other than UV curable into the varnish. To find a method of the present invention that does not particularly require a chemically active group for gelling, maintains the properties of the varnish before it is made into a gel varnish, and can change only the morphology without causing any essential changes. It came to this. Furthermore, it was confirmed that the above object could be achieved by using the gel varnish obtained by the method of the present invention in UV ink. Next, the method of the present invention will be described in detail. The aluminum alcoholate or aluminum chelate compound shown in claim (A) for the constituent materials used in the present invention is, for example, representative examples of aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butyrate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), aluminum tris (acetylacetonate), aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum di-n-butoxide monomethyl acetoacetate, aluminum Examples include diisobutoxide monomethyl acetoacetate, aluminum disec-butoxide monoethyl acetoacetate, and further cyclic aluminum oxide stearate. Typical examples of the aluminum soap represented by (B) include aluminum octylate, aluminum stearate, and aluminum naphthenate. Next, the ultraviolet curable oligomer shown in (C) is
Obtained by reacting 1 mole of an unsaturated dibasic acid or/and unsaturated dibasic acid anhydride, 2 moles of a triol having 4 or more carbon atoms without an ester bond, and 4 moles of acrylic acid or/and methacrylic acid. , is expressed by the following general formula.

[Formula] [M = Acryloyl group or / and methacryloyl group T = Residue of triol D = Residue of unsaturated dibasic acid] This oligomer is a liquid, non-volatile component, and has excellent polymerizability. This is because it has excellent dispersibility as an oligomer that is widely used as a vehicle for UV ink and has a hardenability and pot life. The unsaturated dibasic acids and unsaturated dibasic acid anhydrides used in the synthesis of (C) include fumaric acid,
itaconic acid, citraconic acid, maleic acid, 3,6
Typical examples include -endomethylenetetrahydrophthalic acid, tetrahydrophthalic acid (including four types: △ ¹ -, △ ² -, △ ³ -, △ ⁴ -), and anhydrides thereof. Typical examples of triols having 4 or more carbon atoms and not having an ester bond include trimethylolethane, trimethylolpropane,
1,2,6-hexanetriol, tris(2-
Hydroxyethyl) isocyanurate may be mentioned. There are many oligomers with UV curability that are applied to UV inks, but they do not have any chemically active groups other than UV curability and do not lose the properties mentioned above that should be maintained as an ink vehicle.
It is impossible to obtain a satisfactory gel varnish using (A) or (B) other than (C). The above is a description of each substance constituting the gel varnish of the present invention. Next, a method for producing a gel varnish using these compounds will be described. The gel varnish of the present invention can be obtained by adding gelling agents (A) and (B) to ultraviolet curable oligomer (C), mixing and heating the gelling agents (A) and (B). If either of them is added alone, a satisfactory gel varnish cannot be obtained, so (A) and (B) must be used in combination. However, gelling agents (A) and (B) may be added separately or simultaneously during the reaction, and finally (A),
When both (B) are added, gel varnishing begins. Furthermore, when adding (A) and (B), add (A) in advance.
It is more effective to use (B) after dispersing it in part of (C) or in a suitable organic solvent. Typical examples of such organic solvents include n-hexane, cyclohexane, benzene, toluene, xylene, isopropanol, etc.
When these organic solvents are used, it is preferable to remove them as much as possible during or after the reaction. The gel varnishing reaction is usually carried out at a temperature between 50 and 120°C, but heating significantly above this temperature will cause radical polymerization of the (meth)acryloyl group in (C), resulting in high It should be avoided because it becomes easily molecularized. Further, in order to avoid these polymerization reactions as much as possible, it is necessary to add a thermal polymerization inhibitor. The amount of the thermal polymerization inhibitor used may be in the range of 0.001 to 1.000% based on the total weight of the unsaturated compounds present in the reaction system. Such thermal polymerization inhibitors include hydroquinone, benzoquinone, mono-tert-butylhydroquinone,
Hydroquinone monomethyl ether, P-tert-
Butylcatechol etc. can be mentioned as a typical example. The mixing ratio of (A), (B), and (C) of the gel varnish of the present invention is:
If the total amount is 100 copies, the total amount of (A) and (B) is 0.5 to 20
(C) is in the range of 80 to 99.5 parts, and (A), (B)
The ratio of one is 1 to the other is within 10. (A)
If the total amount of (B) is 0.5 parts or less, or (A) and (B)
If the ratio of one side exceeds 1 and the other exceeds 10, the elasticity of the gel varnish obtained is weak, and conversely (A),
If the total amount of (B) exceeds 20 parts, the performance of (C) may be inhibited, the gelling agent may not be fully dispersed or dissolved in (C) and may remain in the varnish, or the gel varnish may have strong elasticity. Both are impractical because they are too thick and difficult to form into ink. Although the amounts of (A) and (B) added are within this range, in practice, the ratio of (A) and (B) is 1:1 when the total amount of (A) and (B) is 1 to 10 parts. The closer the better. In addition, for the purpose of adjusting the viscosity and various physical properties of the gel varnish of the present invention, 100 parts of (C) may be added to a non-ultraviolet curable resin compatible with (C) and/or a resin containing the same, and a diluent. It may be added at a rate of 1 to 900 parts, preferably 1 to 500 parts. It takes
The resin that is compatible with (C) and has no ultraviolet curability is a non-reactive solid resin, representative examples of which are generally referred to as ketone resins, xylene resins, rosin ester resins, and petroleum resins. In addition, UV-curable resins, diluents that have an allyl group in the molecule such as diallyl phthalate prepolymer and triallyl isocyanurate, general unsaturated polyester resins, and neopentyl glycol di( meth)acrylate, trimethylolpropane tri(meth)acrylate,
1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyethylene glycol di(meth)acrylate, bisphenol A ethylene oxide adduct diacrylate, and generally Representative examples include liquid monomers and oligomers having a methacryloyl group or an acryloyl group in the molecule, such as epoxy acrylate, urethane acrylate, and polyester acrylate. These can be used alone or in combination. A UV-curable printing ink can be obtained by adding a photosensitizer, a UV-curable unsaturated compound, a pigment, a thermal polymerization inhibitor, and other auxiliary agents to the UV ink gel varnish thus obtained. Since the ink can be crosslinked and cured not only by ultraviolet rays but also by electron beams, it can also be applied as an electron beam curing type ink using a suitable electron beam irradiation device. In addition, the UV ink using the gel varnish of the present invention was able to achieve excellent printing effects in letterpress and lithographic printing that are not available with conventional UV inks. Even in lithographic printing that does not use water (waterless lithographic printing), it is possible to obtain printing effects that are not available with conventional UV inks. The lithographic printing that does not use dampening water referred to here refers to Toray's ``waterless lithographic printing'' developed by Toray Industries, Inc. (2-2 Muromachi, Nihonbashi, Chuo-ku, Tokyo). Next, details of the present invention will be explained using the following specific examples. Example 1 A compound obtained by esterifying 1 mole of tetrahydrophthalic anhydride, 2 moles of trimethylolpropane, and 4 moles of acrylic acid, that is, the general formula represented by (C) in the claims, where D is tetrahydrophthalic acid. , T is trimethylolpropane and M is an acryloyl group.
1) (viscosity 43000cps/25℃). 94 parts of this oligomer (C-1) and 0.3 parts of hydroquinone as a thermal polymerization inhibitor were placed in a beaker and heated to 120 parts while stirring.
Heated to ℃. Next, isopropyl alcohol 2
2 parts of ethyl acetoacetate aluminum diisopropylate and 2 parts of aluminum octylate were mixed and dispersed in advance.
After gradually adding it into the beaker, it was stirred for 20 minutes while maintaining the temperature at 100°C. During this time, the isopropyl alcohol added as a solvent was removed from the system to obtain the desired ultraviolet curable gel varnish. Example 2 In the synthesis of (C-1) in Example 1, methacrylic acid was used instead of acrylic acid to produce UV-curable oligomer (C-2) (viscosity 32000 cps/25°C)
I got it. An ultraviolet curable gel varnish was obtained in exactly the same manner as in Example 1 except that (C-2) was used instead of (C-1). Example 3 Similarly, maleic anhydride was used in place of tetrahydrophthalic anhydride in (C-1) in Example 1, and ultraviolet curable oligomer (C-3) (viscosity
An ultraviolet curable gel varnish was obtained in exactly the same manner as in Example 1, except that (C-3) was used in place of (C-1). Examples 4 to 9 Example 1 using oligomer (C-1)
Using the same manufacturing method as above, the compounded substances were prepared in Table 1.
Instead, an ultraviolet curable gel varnish was obtained.
However, in Example 9, the gelling agent was added after the solid resin was completely dissolved. Comparative Examples 1 and 2 Ultraviolet curable non-gel varnishes were obtained using the same manufacturing method as in Example 1 without adding a gelling agent.

[Table] Using the ultraviolet curable gel varnish obtained in Production Examples 1 to 9 of the gel varnish, it was milled in a three-roll mill according to the following formulation for lithographic printing.
Manufactured UV ink. However, the tack value is 15.0±
Trimethylolpropane triacrylate was used in a range of 0 to 5% in order to adjust the temperature to 0.5 (incometer 30°C, 400 rpm). In addition, in order to compare with inks using these gel varnishes, UV inks were produced in the same manner using the non-gel varnishes obtained in Comparative Examples 1 and 2 instead of the gel varnishes. UV gel varnish 50 parts Aronix M-8030 (acrylate oligomer manufactured by Toagosei Kagaku Kogyo Co., Ltd.) 21 parts Red pigment Carmine 6B 20 parts Benzophenone 6 parts 4,4'-bis(N,N diethylamino)benzophenone 3 parts Hydroquinone 0.5 parts Next We conducted a printing test on these inks using a Komori Printing Machinery Sprint Machine, observed the ink's heat change resistance and moisture resistance (emulsification resistance) on the machine, and then placed the printed matter under an ultraviolet irradiation machine. A hardenability test was conducted through. Each test method will be described in detail below. (Heat change resistance test method) Inks with poor heat change resistance have lower ink viscosity as the printing temperature rises, and are more likely to cause stains and changes in print density. Therefore, evaluation was made by observing these during printing. (Moistening water resistance test method) Using a plate with a pattern that makes it easy for ink to emulsify during printing, gradually increasing dampening water, causing the ink to emulsify and not stick to the metal roller, causing "roller baldness". observed. (Ultraviolet curing test method) UV irradiation was performed using a high-pressure mercury lamp at 80 W/cm2, lamp height was 10 cm, and line speed was 70 m/min, and the curing property was evaluated by the degree of stickiness on the printed surface. (Storage stability test method) 100g of ink is sealed in a can and placed in a constant temperature dryer.
After being left at 45°C for 30 days, it was observed whether the ink would polymerize and become a polymer. The criteria for evaluation were very good ◎, good ○, slightly poor △, and poor ×, and the test results are shown in Table 2.

[Table] As shown above, UV ink using gel varnish has superior heat change resistance and moisture resistance compared to UV ink that does not use gel varnish, and also has superior ultraviolet curability, storage stability, etc. It was found that no damage was caused. Furthermore, instead of the red pigment Carmine 6B used in the formulation of the UV ink mentioned above, the yellow pigment Disazo Yellow was used.
Each color is created using the indigo pigment Phthalocyanine Blue, the Japanese ink pigment Carbon Black, and the golden red pigment Lake Red C.
When we produced UV ink and conducted similar tests, we obtained similar good results compared to ink that did not use gel varnish.

Claims (1)

[Scope of Claims] 1 (A) aluminum alcoholate or aluminum chelate compound and (B) aluminum soap used in combination (C) ester bond with 1 mole of unsaturated dibasic acid or/and unsaturated dibasic acid anhydride carbon number 4 without
A UV-curable oligomer synthesized from 2 moles of the above triol and 4 moles of acrylic acid or/and methacrylic acid and having the following general formula [Formula] [M = acryloyl group or/and methacryloyl group T = residue of triol D = non-containing residue of a saturated dibasic acid] and heating, and the weight mixing ratio of each substance (hereinafter all mixing ratios are weight ratios) is the same as that of (A), (B), and (C). If the total quantity is 100 copies
Total amount of (A) and (B) is 0.5 to 20 parts, and (C) is 80 to 80 parts.
99.5 parts of ultraviolet curable gel varnish for printing ink, characterized in that the ratio of (A) and (B) is within 1 to 10.