JP3367112B2 - Active energy ray-curable ink composition for offset printing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition which is cured by irradiation with an active energy ray such as an ultraviolet ray or an electron beam. The present invention relates to an active energy ray-curable ink composition for offset printing exhibiting stability. [0002] In offset printing using a plastic sheet, surface-treated paper or the like as an object to be printed, the curing of the ink is carried out instantaneously at room temperature. In many cases, ink is used.
However, when compared with sheet-fed printing inks using oxidative polymerization as a curing mode, it is said that it is difficult to adjust the emulsified state because of their low viscoelasticity and high polarity. In particular, since materials such as plastic sheets and surface-treated paper do not absorb water, it becomes more difficult to adjust the amount of dampening water as compared to offset printing of paper that absorbs a moderate amount of water. If the fountain solution supply is too low, the print density will increase sharply and eventually the background will be smeared. Conversely, if the fountain solution supply is too high, the ink will emulsify beyond the appropriate conditions. And the print density becomes extremely low. The addition of various auxiliaries has been proposed to improve this point, but none has been decisive. In particular, when a surfactant is added to an ink as an auxiliary agent without considering the HLB value and an appropriate amount, the fluidity of the ink may be seriously impaired, or the ink may be entangled with a roller for supplying a dampening solution. When the amount of water supplied during printing is too small, the ink cannot be maintained in an appropriate emulsified state, and at the same time, the dampening solution film on the non-image area of the plate becomes thin. Is transferred and ink stains occur on printed matter. [0003] The present inventors have made intensive studies on an active energy ray-curable ink composition having a wide supply range of dampening solution during offset printing, and have reached the present invention. did. According to the present invention, an HLB value of 1 is set.
An active energy ray-curable ink for offset printing, characterized in that the ink contains at least one of two or more nonionic surfactants or anionic surfactants in an amount of 0.01 to less than 0.1% by weight in the ink. It relates to a composition. [0005] The HLB value is defined as a Hydrophilic Lip.
This is an abbreviation of ophilic (lipophilic) Balance, and is described in, for example, "Emulsification and Solubilization Techniques" (June 20, 1976, by Tsuji Osamu, published by Kogyo Tosho Co., Ltd.), pages 8 to 15. Is what it is. There are several methods for calculating the HLB value. In the present invention, the following formula based on the organic-inorganic method is used. The inorganic value and the organic value in the formula are values specific to the functional groups. HLB value = inorganic value / organic value × k (k:
The nonionic surfactant used in the present invention includes polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin fatty acid ester, and polyethylene. Glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether,
Polyoxyethylene alkyl phenyl ether, polyoxyethylene castor oil, polyoxyethylene hardened castor oil, polyoxyethylene phytosterol, polyoxyethylene phytostanol, polyoxyethylene lanolin, polyoxyethylene lanolin alcohol, polyoxyethylene alkylamine, polyoxy Examples thereof include ethylene fatty acid amide and polyoxyethylene alkylphenyl formaldehyde condensate. The anionic surfactants used in the present invention include alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids and salts thereof, N-acylmethyl taurine salts, and polyoxyethylene alkyl ether acetates. , Alkyl sulfocarboxylates, α-olefin sulfonates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, and the like. Even when a surfactant having an HLB value of less than 12 alone is added to the ink in the range of 0.01% by weight or more and less than 0.1% by weight, the fountain solution particles remain in the emulsified state of the ink. The effect of fine dispersion is low. Therefore, the effect of stabilizing the emulsified ink is low, that is, the sole addition of a surfactant having an HLB value of less than 12 is not very useful for stabilizing the density during offset printing. The appropriate amount of the surfactant having a high HLB value to be added to the ink is selected in the range of 0.01% by weight or more and less than 0.1% by weight depending on the viscoelasticity of the ink and the type of the material used (particularly, pigment). And preferably 0.02 to
It is desirable to select within the range of 0.09% by weight. High H
LB value When the amount of the surfactant added is less than 0.01% by weight, the effect of increasing the density stability during offset printing is low, and when the amount exceeds 0.1% by weight, the ink at the time of emulsification is an appropriate amount. The dampening solution tends to absorb more than the dampening solution, causing a phenomenon that the ink is accumulated in the ink mixing roller and a phenomenon that the emulsified ink is entangled with the dampening solution supply roll. When the amount of the surfactant having a high HLB value is in the range of 0.01% by weight or more and less than 0.1% by weight, the curing ability by ultraviolet rays and electron beams is not impaired. When two or more surfactants are used as a mixture, an HLB value of 12 is obtained by calculation based on the addition theory.
As described above, it is necessary to add them so that the total amount of the additives is in the range of 0.01% by weight or more and less than 0.1% by weight. However, when a plurality of surfactants are mixed and used, any of them may be HLB 12 or less, but it is necessary that the calculated value based on the addition theory is 12 or more. When adding this surfactant, even if it is mixed with other materials before the ink manufacturing process,
Similar effects can be obtained by adding the ink to an already completed ink later. In the present invention, as the polymerizable compound having an ethylenically unsaturated double bond, monomers having an average molecular weight of less than 1000 and having an ethylenically unsaturated double bond, and a monomer having an average molecular weight of 1,000 or more and an ethylenically unsaturated double bond are used. Oligomers having a bond can be used. The functional group of the ethylenically unsaturated double bond is an acryloyl group,
Examples thereof include a methacryloyl group, an allyl group, and a methallyl group. From the viewpoint of curability, use of a polymerizable compound having at least an acryloyl group or a methacryloyl group (hereinafter abbreviated as (meth) acryloyl group) is preferable. Specific examples of the monomer include tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxytrimethylolpropane tri (meth) acrylate, glycerol propane tri (meth) acrylate, and propoxy triacrylate. Methylolpropane tri (meth) acrylate,
Examples thereof include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate, and there is no problem even if they are mixed and used. The oligomer includes unsaturated polyester, polyester (meth) acrylate, epoxy (meth) acrylate, rosin-modified epoxy (meth)
Examples include various chemically modified epoxy (meth) acrylates represented by acrylate, polyester urethane (meth) acrylate, diallyl phthalate resin and the like, and there is no problem even if they are mixed and used. The photopolymerization initiator optionally used in the present invention includes benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, acetophenone, 2,2-dimethoxy-2-acetophenone, Acetophenones such as 2,2-diethoxy-2-acetophenone and 1,1-dichloroacetophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone,
Anthraquinones such as 1-chloroanthraquinone, 2-amylanthraquinone, thioxanthones such as 2,4-dimethylthioxanthone, 1-chlorothioxanthone and 2,4-diisopropylthioxanthone, ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal, benzophenone Or benzophenones such as derivatives thereof, such a photopolymerization initiator,
According to a conventional method, it may be used in combination with one or more known and commonly used sensitizers such as benzoate esters or tertiary amines. Further, the active energy ray-curable ink composition for offset printing of the present invention may contain any resin such as a saturated polyester containing no ethylenically unsaturated double bond.
Furthermore, organic pigments, inorganic pigments or extenders, and ink auxiliaries may be used in combination. These amounts can be arbitrarily set according to the printing suitability of the ink, the curability, and the physical properties of the cured film. In general, when the entire ink composition is 100% (based on weight%), oligomers; 0 to 80%, monomer; 0 to 80%, polymerization initiator (including sensitizer); 0 to 15%, color pigment;
%, Extender pigment; 0 to 40%, resin containing no ethylenically unsaturated double bond; 0 to 40%, ink auxiliaries;
% Is preferably used. Next, examples are introduced, but the present invention is not limited to the contents. EXAMPLES Example 1 Weight% Coloring Pigment Phthalocyanine Blue 18.0 Extender Pigment Calcium Carbonate 2.0 Polymerization Initiator 2-Methyl-1- (4-methylthio) -2-.. 5.0 Morpholinopropanone-1 Polymerization Inhibitor t-Butylhydroquinone 0.05 Resin Diallyl phthalate resin (Note) 12.0 Monomer dipentaerythritol hexaacrylate 49.5 Trimethylolpropane triacrylate 13.45 Total 100.0 Note) Osaka Soda ( Daiso Dap A manufactured by Nihon Kagaku Co., Ltd. A nonionic surfactant TAMNS-10 manufactured by Nikko Chemicals (polyoxyethylene stearylamine, 0 about 14) LB value.
08% by weight, and the resulting mixture was well ground with a three-roll mill to obtain Ink-1. Example 2 0.08% by weight of anionic surfactant Sarkosinate LN (lauroyl sarcosine sodium, HLB value of about 30) manufactured by Nikko Chemicals was added to the base ink, and the mixture was thoroughly milled with a three-roll mill. Ink-2
And Comparative Example 1 Ink-3 was prepared by adding no surfactant having an HLB of 12 or more to the base ink. Comparative Example 2 To the base ink, 0.3% by weight of anionic surfactant Sarkosinate LN manufactured by Nikko Chemicals was added.
Ink-4 was obtained by thoroughly milling with three rolls. Example 1, Example 2, Comparative Example 1, Comparative Example 2
A printing test for confirming the water width was performed using each of the above inks. The printing press, plate, paper, and fountain solution used are as follows. Printing machine; Roland R201 PS plate; Positive type PS plate RP paper made by Polychrome Japan; Diamond coat made by Jujo Paper (using a forty-sixth plate with four trees) dampening water; 95% by weight of tap water and domestically produced isopropyl alcohol (Primary) Using a solution obtained by adding 5% by weight of NT liquid K701 manufactured by Dainippon Ink
Dilution of 00 times The printing conditions at room temperature and printing speed were as follows. Room temperature; 25 ± 1 ° C. Printing speed: 8,000 sheets / hour (52.5 m / min.) Specifically, the scale 30 of the dampening water supply device
Printing is started at (the dial scale value of the standard supply water amount), and after printing about 2000 sheets, the scale of the supply device is lowered to 25, 20, and 15. Approximately 200 sheets were printed at each scale setting, and the scale value at which background contamination occurred and the degree of contamination were recorded. Next, the feeder scale is set to 30
Then, the scale was increased to 30, 40, 45, and 50, and the scale and the degree at which the occurrence of the water mark was confirmed were recorded as in the case where the scale was lowered. The range of the scale value at which the water mark is generated from the scale value at which the background stain occurs is the water width, and the wider the range, the better the workability of the ink. If necessary, use a cold mirror type small UV irradiator (manufactured by Eye Graphic, number of lamps 1, lamp output 120W / cm, line speed 20m
/ Min. ), The printed matter obtained in the above test was dried, and the cured film was evaluated with respect to abrasion resistance, scratch resistance and the like. Table 1 shows Example 1, Example 2, Comparative Example 1,
The test results for Comparative Example 2 are shown. In comparison with Ink-3 which does not contain a surfactant having an HLB value of 12 or more, H
Ink containing an appropriate amount of a surfactant having an LB value of 12 or more
1. The water width of Ink-2 was wide, and the print density stability against fluctuations in the amount of dampening water supplied was high. HL
Ink containing an excessive amount of a surfactant having a B value of 12 or more
No. 4 hardly causes soiling when the supply water amount is low, but the water mark is generated at the supply water amount of 37.5%.
Further, as an adverse effect due to excessive addition of a surfactant having an HLB value of 12 or more, roller accumulation occurs in the ink supply system. Roller accumulation means that the transferability of the ink emulsified by the fountain solution is remarkably reduced, and the ink is not completely transferred from the ink supply system of the printing press onto the printing medium. This is a phenomenon in which ink accumulates in the ink. [Table 1] According to the present invention, the dampening solution supply range during offset printing can be widened without impairing other printability.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-142066 (JP, A) JP-A-3-296575 (JP, A) JP-A-51-53909 (JP, A) JP-A-2- 238013 (JP, A) JP-A-48-33912 (JP, A) JP-A-54-111902 (JP, A) JP-A-61-138677 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) C09D 11/00-11/20 B41F 1/16 B41F 7/02

Claims (1)

(57) [Claim 1] In an active energy ray-curable ink for offset printing containing a polymerizable compound having an ethylenically unsaturated double bond, a nonionic interface having an HLB of 12 or more. An active energy ray-curable ink composition for offset printing, comprising at least one kind of an activator or an anionic surfactant in the ink in an amount of 0.01% by weight or more and less than 0.1% by weight.