JP2936528B2 - W / O emulsion ink for stencil printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a W / O emulsion ink for stencil printing. More specifically,
The present invention relates to a W / O emulsion ink suitable for use in a rotary printing press for stencil printing, which can improve the fixability of the ink in a printed image and further increase the image density.

[0002]

2. Description of the Related Art In recent printing technologies, there have been remarkable technological advances, and it has become possible to obtain better printed materials. Further, it is required that the image of the printed matter can be stored as it is. However, in the image of a conventional stencil printing machine, the non-image area may be stained by the friction between the printed paper and the paper when the paper is handled by hand, or the hand of a worker who handles the paper may be damaged. And had hygienic problems. This is because pigments that are conventionally used as colorants for emulsion inks and that have a diameter larger than the pores on the paper surface, or that oil or other vehicles penetrate into the paper quickly and are left on the paper. Is separated by friction between paper and paper or a worker's hand, and adheres to a non-image area or a hand.

[0003]

Heretofore, in order to improve the above-mentioned disadvantages, a varnish has been added to the ink.
Measures have been taken to increase the fixing property between the pigment and the paper and to increase the fixing property. However, even with this, the above-described problem has occurred, and further improvement in fixability is required.

Accordingly, an object of the present invention is to overcome the above-mentioned disadvantages, to maintain a good printed image in a rotary printing press for stencil printing, and to prevent the hands from being stained by the printed image. Is to provide.

[0005]

Means for Solving the Problems The present inventors have improved the fixability without impairing the safety and storage stability of a W / O emulsion ink, and have improved the non-image area and hand stains due to friction. As a result of intensive studies to eliminate this, it has been found that the use of an oil-soluble dye as a coloring agent achieves the above object, and that the image density can be increased.

That is, according to the present invention, there is provided a W / O emulsion ink for stencil printing characterized by containing an oil-soluble dye as a colorant, and containing an oil-soluble dye / pigment mixture as a colorant. A W / O emulsion ink for stencil printing is provided.

[0007] The oil-soluble dye, even when dissolved or dispersed in a solvent, has a diameter significantly smaller than the diameter of the pigment. Therefore, the oil-soluble dye also penetrates into the fine pores of the paper together with the solvent, does not remain on the paper like the pigment, and does not peel off due to friction. Therefore, W / O
By using an oil-soluble dye as a coloring agent in the oil phase of the emulsion ink, fixability can be significantly improved. The increase in image density is considered to be due to the strength of the coloring power, which is an advantage of the dye.

In the present invention, an oil-soluble dye / pigment mixture may be used as a colorant. In particular, when 1 to 40% by weight of an oil-soluble dye is used in combination with the pigment, the excellent water resistance and light fastness of the pigment are not impaired, and other image characteristics such as see-through, see-through, and bleeding in an image are reduced. Without having the drawbacks described above, the fixability can be improved,
Very preferred.

The emulsion ink of the present invention preferably has an oil phase of 5 to 50% by weight and an aqueous phase of 50 to 95% by weight. When using the oil-soluble dye to be used together with the pigment,
The color of the oil-soluble dye is not always the same as the color of the pigment used. As the oil phase, oil-soluble dyes, pigments, resins,
Oil, dispersant, emulsifier, gelling agent, etc., and the aqueous phase is composed of water, water-soluble resin, preservative, water evaporation inhibitor, antifreeze, pH adjuster, antioxidant, electrolyte, etc. ing.

[0010] Oil-soluble dyes include Butter Yellow, Sudan Orange RR, Sudan Brown R, Sudan Red B
B, Sudan Black B, Sudan Red 3R, Sudan Violet R, Sudan Blue GL, and Sudan Green BB. These can be used alone or in combination. The amount used is 0.
It is preferably from 0.01 to 5.00% by weight.

When an oil-soluble dye and a pigment are used in combination, the pigment may be an azo pigment, a phthalocyanine pigment, a nitroso pigment, a nitro pigment, a vat dye pigment, a mordant dye pigment, a basic dye pigment. Known pigments such as acidic dye pigments and natural dye pigments are exemplified. These can be used alone or in combination. In this case, the amount of the oil-soluble dye used is preferably 1 to 40% by weight of the amount of the pigment used. The amount of the pigment used is preferably 1 to 20% by weight based on the ink.

[0012] Examples of the pigment dispersant or emulsifier for constituting the W / O emulsion include glycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, pentaerythritol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene sorbitan. Ethylene sorbite fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene phytosterol, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene castor oil, poly Oxyethylene hydrogenated castor oil, polyoxyethylene lanolin, polyoxyethylene lanolin Call, polyoxyethylene alkylamine, polyoxyethylene fatty acid amides, nonionic surfactants such as polyoxyethylene alkylphenyl formaldehyde condensates and the like. They are,
One or more can be used. The use amount of the surfactant is preferably 1 to 20% by weight based on the ink.

As the oil, known mineral oils, vegetable oils, and hydrocarbon-based synthetic oils can be used alone or in combination. Mineral oils include petroleum solvents, spindle oils, liquid paraffin, motor oils, gear oils, and machine oils, and vegetable oils include linseed oil, tall oil, corn oil, soybean oil, castor oil, and dehydrated castor oil. No. These can be used alone or in combination. The amount of the oil used is preferably 5 to 30% by weight based on the ink.

A resin is used for the purpose of improving the adhesion between the ink and paper, the dispersibility of the pigment, the stability over time of the ink, and the like. Examples thereof include rosin, polymerized rosin, hydrogenated rosin, rosin ester, and hydrogen. Rosin ester, rosin-modified phenol, alkyd resin, polymerized castor oil and the like. These can be used alone or in combination.
The amount of the resin used is preferably 1 to 15% by weight in the ink.
In addition, a pigment dispersant such as aluminum chelate and a gelling agent can be appropriately selected and used for the oil phase in order to improve ink stability and pigment dispersibility.

The water used for the aqueous phase is tap water, purified water,
Any of ion-exchanged water may be used, and the use amount is preferably 20 to 70% by weight based on the ink. As the water-soluble resin used for moisturizing or thickening, acrylic resin, gum arabic and the like are used. The amount used is preferably from 1 to 15% by weight based on the ink.

To suppress water evaporation or prevent freezing, a water-soluble organic solvent may be used in the aqueous phase. Examples thereof include glycols such as ethylene glycol, diethylene glycol and propylene glycol, methanol, ethanol, isopropanol, and the like. Alcohols such as butanol and isobutanol; and glycerin. These organic solvents can be used alone or in combination. The amount used is preferably 0.5 to 10% by weight based on the ink.

In addition, a preservative, a pH adjuster, an antioxidant, an electrolyte for stabilizing an emulsion, a rust inhibitor for preventing corrosion of metal parts, an antifoaming agent, etc. may be used alone or in plural in the aqueous phase. Can be selected and used.

The oily phase is usually prepared by dispersing a pigment using a known dispersing machine and diluting the pigment with oil or another oily phase composition.
In general, a known stirrer is used for dilution. In the aqueous phase,
The aqueous phase composition is usually mixed by a stirrer. The completed oil phase and aqueous phase are easily emulsified using a known emulsifier. Production methods and means such as dispersion, dilution, and emulsification can be appropriately changed.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In addition, all the parts shown below are based on weight.

Example 1 Sudan Black B (colorant) 3.0 parts Spindle oil (solvent) 15.0 parts Rosin-modified phenolic resin (resin) 5.0 parts Sorbitan sesquioleate (surfactant) 3.7 parts Polyoxysorbitan monooleate (surfactant) 2.3 parts Dibutylhydroxytoluene (antioxidant) 0.1 part Water 70.8 parts Methyl parahydroxybenzoate (preservative) 0.1 part

The above-mentioned rosin-modified phenolic resin was heated and dissolved in spindle oil at 150 ° C., and Sudan Black B, sorbitan sesquioleate and sorbitan monooleate were subjected to dispersion treatment with a three-roll mill to obtain an oil phase. While gradually adding an aqueous solution in which methyl parahydroxybenzoate was dissolved to the oil phase, the mixture was stirred with a conventionally known emulsifier to obtain an emulsion ink having the above composition. Using this emulsion ink, Ricoh VT3500
Machine printed. I. of the print image D. Was measured with a Macbeth densitometer (manufactured by Macbeth), and the I.C. D. Was measured, and the ratio between the two was calculated. Hereinafter, this ratio is referred to as a fixing rate.

Example 2 2.7 parts of furnace carbon black 0.3 parts of Sudan Black B 15.0 parts of spindle oil 5.0 parts of rosin-modified phenol resin 5.0 parts 3.7 parts of sorbitan sesquioleate 2.3 parts of sorbitan monooleate Dibutylhydroxytoluene 0.1 part Water 70.8 parts Methyl parahydroxybenzoate 0.1 part

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 3 Furnace carbon black 2.8 parts Sudan blue GL 0.2 parts Spindle oil 15.0 parts Rosin-modified phenol resin 5.0 parts Sorbitan sesquioleate 3.7 parts Sorbitan monooleate 2.3 parts Dibutyl Hydroxytoluene 0.1 part Water 70.8 parts Methyl parahydroxybenzoate 0.1 part

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Comparative Example 1 Furnace carbon black 3.0 parts Spindle oil 15.0 parts Rosin-modified phenolic resin 5.0 parts Sorbitan sesquioleate 3.7 parts Sorbitan monooleate 2.3 parts Dibutylhydroxytoluene 0.1 part Water 70.8 parts Methyl parahydroxybenzoate 0.1 part

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 4 Phthalocyanine Green 4.0 parts Sudan Green BB 0.5 parts Petroleum-based solvent 25.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 5.0 parts Dibutylhydroxytoluene 0.1 parts Water 55. 7 parts Methyl parahydroxybenzoate 0.1 part Glycerin (water evaporation inhibitor) 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 5 Phthalocyanine green 4.2 parts Butter yellow 0.3 parts Petroleum solvent 25.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 5.0 parts Dibutylhydroxytoluene 0.1 parts Water 55.7 Part Methyl parahydroxybenzoate 0.1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Comparative Example 2 Phthalocyanine Green 4.5 parts Petroleum-based solvent 25.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 5.0 parts Dibutylhydroxytoluene 0.1 parts Water 55.7 parts Methyl parahydroxybenzoate 0 .1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
The printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 6 Phthalocyanine Blue 4.0 parts Sudan Blue GL 0.5 parts Petroleum-based solvent 25.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 5.0 parts Dibutylhydroxytoluene 0.1 parts Water 55.7 Part Methyl parahydroxybenzoate 0.1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
The printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 7 Phthalocyanine blue 4.2 parts Butter yellow 0.3 parts Petroleum solvent 25.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 5.0 parts Dibutylhydroxytoluene 0.1 parts Water 55.7 Part Methyl parahydroxybenzoate 0.1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
The printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Comparative Example 3 Phthalocyanine Blue 4.5 parts Petroleum-based solvent 25.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 5.0 parts Dibutylhydroxytoluene 0.1 parts Water 55.7 parts Methyl paraoxybenzoate 0 .1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
The printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 8 3.5 parts of Stylonium Red 3.5 parts of Sudan Red BB 1 part of petroleum-based solvent 5.0 parts of alkyd resin 4.5 parts of sorbitan sesquioleate 4.5 parts of 0.1 part of dibutylhydroxytoluene 7 parts Methyl parahydroxybenzoate 0.1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Example 9 3.7 parts of stylonium red 3.7 parts of butter yellow 0.3 parts of a petroleum solvent 15.0 parts of an alkyd resin 5.0 parts 4.5 parts of sorbitan sesquioleate 0.1 part of dibutylhydroxytoluene 7 parts Methyl parahydroxybenzoate 0.1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
The printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Comparative Example 4 Strontium Red 4.0 parts Petroleum-based solvent 15.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 4.5 parts Dibutylhydroxytoluene 0.1 parts Water 66.7 parts Methyl paraoxybenzoate 0 .1 part Glycerin 4.6 parts

The above composition was emulsified in the same manner as in Example 1 to obtain an emulsion ink. VT3 using this
Printing is performed at I.500, and I.500 printing is performed in the same manner as in the first embodiment. D
And the fixation rate were measured.

Examples 1, 2, and 3 and Comparative Example 1, Example 4,
5, Comparative Example 2, Examples 6, 7 and Comparative Example 3, Examples 8, 9
And the results of Comparative Example 4 are shown in Tables 1 to 4, respectively.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

[Table 4]

From the results shown in Tables 1 to 4, it can be seen that the emulsion ink of the present invention improves the fixing property of an image and also improves the image density.

[0052]

The emulsion ink for stencil printing of the present invention has a constitution in which an oil-soluble dye or an oil-soluble dye / pigment mixture is contained as a colorant, so that the storage stability, safety and image characteristics of the ink are improved. The fixability of the ink to the paper is improved without any loss. This prevents the printed matter and the operator's hands from being stained by the friction of the image. Further, according to the emulsion ink of the present invention, the image density can be increased.

Claims (4)

(57) [Claims] 1. A W / O emulsion ink for stencil printing comprising an oil-soluble dye as a colorant. 2. A stencil printing W / O emulsion ink comprising an oil-soluble dye / pigment mixture as a colorant. 3. The W / O emulsion ink for stencil printing according to claim 1, wherein the W / O emulsion ink contains a resin. 4. The W / O emulsion ink for stencil printing according to claim 1, comprising 5 to 50% by weight of an oil phase and 50 to 95% by weight of an aqueous phase. .