JPH0530871B2 - - Google Patents

Description

[Detailed description of the invention]

``Object of the Invention'' (Industrial Application Field) The present invention relates to an emulsion ink, and more particularly to an emulsion ink suitably used in letterpress printing and flexographic printing for newspapers and books. (Prior art) Normally, oil-based ink used in letterpress printing etc. is affected by centrifugal force and static electricity in the roller part of the printing machine.
The so-called misting phenomenon, in which a portion of the oil-based ink becomes granular or filamentous and scatters in the air, contaminates printing machines and printed matter, and also has a negative impact on printing workers. In addition, the oil-based inks normally used in letterpress printing etc. are composed of colorants, mineral oil, vegetable oil, synthetic resin vehicles, natural resin vehicles, or mixtures thereof, and are therefore flammable and burn a high number of calories. In particular, low viscosity ink of 100 poise or less is in a completely liquid state, so there is a great risk of fire, and it is classified as a dangerous substance under the Fire Service Act. Furthermore, ordinary oil-based inks do not have very good affinity with paper, so the transferability from the plate to the paper is not sufficient, and the image quality of printed matter is not smooth. Further, after printing, the low viscosity vehicle and mineral oil in the oil-based ink permeate into the paper and cause the image to show through on the opposite side, causing so-called strike-through or strike-through phenomena, which deteriorates the image quality of printed matter. Among these drawbacks, emulsion ink has been developed as an ink to prevent misting and the risk of fire, but in general emulsion ink, the water-based component is mainly alcohol, or it uses water. However, emulsions have insufficient stability and water content, and there is no emulsion that satisfactorily satisfies both effects. In addition, although the emulsion ink shown in JP-A-55-5946 that uses nonionic activators with HLB7 to HLB13 can prevent misting and fire hazards, it also causes problems in printed matter such as transferability and strike-through. A sufficient effect could not be obtained in terms of image quality. Furthermore, emulsion inks are known, such as those disclosed in JP-A-58-8970, which use amine salts or alkali metal salts of wax oxidation product acids as emulsifiers. In other words, emulsion inks using oxides of mineral waxes or neutralized products of such oxides have a strong odor characteristic of wax oxides, which may worsen the printing environment, or use wax oxides with less odor. Emulsion ink is insufficient in terms of stability and fluidity suitable for printing. (Problems to be Solved by the Invention) In order to solve the above-mentioned problems and obtain excellent printed matter, the inventors of the present invention have developed an emulsion ink using maleated wax or its derivatives as a result of intensive research. It has been found that by creating this method, an ink with little odor, no misting, and no risk of fire can be obtained. We have also completed an emulsion ink that has excellent transfer properties to paper even with light printing pressure, has low strike-through and strike-through, and has good printing effects. "Structure of the Invention" (Means for Solving Problems) The present invention provides a printing emulsion ink containing an oil-based component such as a pigment, mineral oil, or resin, and an aqueous component such as water or alcohol. or a derivative thereof. Maleated waxes or derivatives thereof used in the present invention are maleated or maleated waxes such as paraffin waxes, microcrystalline waxes, and polyethylene waxes that contain alkali metals, alkaline earth metals, ammonia, It is made by neutralizing it with amine etc. Maleation is generally an addition reaction of wax with maleic anhydride through a radical reaction and/or a thermal addition reaction (ene reaction) to a non-conjugated double bond. To explain an example of a maleation reaction, for example, maleic anhydride is added to polyethylene wax (having double bonds), and while adding an organic peroxide,
When heated and stirred at 150°C or higher, a radical reaction occurs, maleic anhydride is added to the double bonds of the polyethylene wax, and a maleated polyethylene wax is obtained. Furthermore, when maleic anhydride is added to paraffin wax and the mixture is heated and stirred at 150°C or higher while adding an organic peroxide, a radical reaction occurs and a maleated product of paraffin wax is obtained. In addition, for example, when maleic anhydride is added to polyethylene wax and heated and stirred at 200°C or higher in a nitrogen atmosphere, an ene reaction occurs and maleic anhydride is thermally added to the double bonds of the polyethylene wax, resulting in maleic acid of polyethylene. is obtained. Furthermore, the maleates of these waxes can be neutralized to form derivatives. Among maleated waxes or derivatives thereof prepared by the above methods, those having the following properties are particularly suitable for the emulsion ink of the present invention. Hardness (penetration) ASTMD-1321 10 or more Acid value ASTMD-1386 50 or more Melting point ASTMD-127 30-70℃ Specific products such as maleated waxes or derivatives thereof include Nippon Oil Co., Ltd.'s
PO wax S-10, 20, 30 (hardness 12-33, acid value 55
~90℃, melting point 51~66℃). The reasons why they are suitable are as follows: 1) A maleated wax or a derivative thereof having a hardness of less than 10 impairs the fluidity of the emulsion ink and may also make the stability of the emulsion unstable. 2) If the acid value is less than 50, the stability of the emulsion ink will be insufficient, and there will be a drawback that the above-mentioned excellent performance as an emulsion ink cannot be obtained. 3) Those with a melting point exceeding 70°C have poor fluidity as emulsion inks and also have poor emulsion stability. In carrying out the present invention, if the maleated wax having the above properties is liquid, it may be used as is, or if it is solid, it may be used after being melted and dispersed in mineral oil. The emulsion ink of the present invention is an ink whose main components are pigments, oily components such as mineral oil and resin, aqueous components such as water and alcohol, and maleated wax or derivatives thereof. As other components, for example, surfactants, extender pigments, rosin, etc. can be used as necessary. The composition ratio of emulsion ink is oil-based component
For 100 parts by weight, 1 to 20 parts by weight of the maleated wax or its derivative and 20 to 80 parts by weight of the aqueous component are preferable. The emulsion ink is prepared by dissolving 5 to 25 parts by weight of pigment as an oil-based component in one or more of mineral oil, drying oil, natural resin, or synthetic resin, for example, resin in mineral oil or drying oil. The mixture is mixed with 75 to 95 parts of a vehicle, and then ground and dispersed using a sand mill, three rolls, or the like. To 100 parts of this oily component, 1 to 20 parts of the above maleated wax or its derivative is thoroughly mixed with a stirrer, and then 20 to 80 parts of aqueous components such as water, alcohol, surfactant, etc. are mixed with a high-speed stirrer. and emulsion. Oil-soluble surfactants for oily components, such as HLB8
The following polyoxyethylene-based, sorbitan-based, and aliphatic glyceride-based products are added to the aqueous component.
An even more stable emulsion ink can be obtained when a polyoxyethylene-based, alkylbenzene-based, or alkylnaphthalene-based anionic surfactant with HLB-12 or higher is used in combination. As described above, by using the maleated wax or its derivative according to the present invention,
A very stable emulsion ink has been prepared, and when used in rotary letterpress printing, it produces a weak odor during printing, exhibits good printability with little misting, and prints with minimal strike-through. It has good transferability to paper and produces an effect similar to offset printing. Examples are shown below. In the examples, "part" and "%" indicate parts by weight and weight %. Example 1 Natural resin vehicle (25% Gilsonite, 75% spindle oil) 15 parts High viscosity mineral oil (50-100 poise petroleum fraction) 100 parts Carbon black 12 parts Navy blue 2 parts Low viscosity mineral oil (Spindle oil) 25 The above mixture is kneaded using a sand mill or three-roll kneading machine, and 10 parts of mineral oil dispersion of wax maleate (PO wax S-30, containing 50%) is added, stirred and mixed. make. To this, 25 parts of water and 1 part of Demol N (surfactant manufactured by Kao Soap Co., Ltd.) are added and stirred with a high-speed stirrer to obtain an emulsion ink. Example 2 Synthetic resin vehicle (Tamanol 354 (rosin-modified phenolic resin manufactured by Arakawa Chemical Co., Ltd.) 40%, linseed oil 35%, spindle oil 25%) 20 parts high viscosity mineral oil 10 parts phthalocyanine blue 8 parts low viscosity mineral Mix 25 parts or more of oil, knead with a sand mill or three-roll kneader, and add 15 parts of mineral oil dispersion of wax maleate (PO wax S-10, containing 50%) sorbitan diglycerin fatty acid Add 1 part of ester and stir to mix to make an oily component. To this, 20 parts of water and 1 part of polyoxyethylene fatty acid ester are added and stirred with a high-speed stirrer to obtain an emulsion ink. Example 3 Natural resin vehicle 5 parts High viscosity mineral oil 15 parts Carbon black 10 parts Phthalocyanine blue 1 part Low viscosity mineral oil 25 parts The above was kneaded in a sand mill or three-roll kneader, and further mixed with maleated wax. mineral oil dispersion (PO
Add 1 part of 7-part fatty acid monoglyceride (Wax S-30, 50% content) and stir and mix to create an oily component. To this, 35 parts of water and 1 part of Demol N are added and stirred with a high-speed stirrer to obtain an emulsion ink. Comparative example Natural resin varnish 5 parts High viscosity mineral oil 15 parts Carbon black 10 parts Navy blue 1 part Low viscosity mineral oil 25 parts The above was kneaded in a sand mill or three-roll kneader, and then sorbitan diglycerin fatty acid ester Add 2 parts and 6 parts of paraffin wax dispersion in mineral oil and stir to mix to form an oily component. To this, 35 parts of water and 1 part of Demol N were added and stirred with a high-speed stirrer to form an emulsion ink, but it thickened during storage and the emulsion stability was poor. Therefore, the following printing was not possible. Table 1 shows the performance comparison results between the current rotary letterpress ink and the emulsion inks of Examples 1 and 3.

[Table] (1) Bluefield viscosity
(2) Visual judgment
(3) Rub it with your finger and check the dirt on your finger Table 2 shows currently used letterpress rotary indigo ink and Example 2
The results of a performance comparison with emulsion ink are shown below.

【table】

Claims (1)

[Scope of Claims] 1. An emulsion ink for printing containing an oil component such as a pigment, mineral oil, or resin, and an aqueous component such as water or alcohol, which is characterized by containing a maleated product of wax or a derivative thereof. Jiyoung ink. 2. The emulsion ink according to claim 1, which comprises 1 to 20 parts by weight of a maleated wax or a derivative thereof and 20 to 80 parts by weight of an aqueous component per 100 parts by weight of an oil component.