JPH069912A - W/o emulsion ink for stencil printing - Google Patents

Abstract

PURPOSE:To improve the fixation of an ink to paper, prevent the staining of a print, etc., due to friction of an image, and obtain a high-density image by using an oil-sol. dye or an oil-sol. dye/pigment mixture as a colorant. CONSTITUTION:As a colorant is used an oil-sol. dye (e.g. Sudan Orange) or an oil-sol. dye/pigment mixture comprising a pigment (e.g. a phthalocyanine pigment) and an oil-sol. dye in an amt. of 1-40wt.% of the pigment. 5-50wt.% oil phase contg. the colorant, etc., and 95-50wt.% aq. phase contg. an antiseptic agent. etc., are stirred on an emulsifying machine to produce the title ink. Since the particle size of the dye is remarkably smaller than that of the pigment. the dye permeates into micropores of paper together with a solvent without leaving a residue behind on the paper, exhibiting no separation due to friction and greatly improving the fixation of the ink.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a W / O type emulsion ink for stencil printing. For more details,
The present invention relates to a W / O emulsion ink suitable for a rotary printing machine for stencil printing, which is capable of improving the fixability of the ink in the image of a printed matter and further increasing the image density.

[0002]

2. Description of the Related Art In recent printing engineering, 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 preserved in good condition. However, in the image of the conventional stencil printing machine, the non-image area is stained by the friction between the printed paper and the image when it is handled by hand, or the hand of the operator who handles the paper. There was a problem in hygiene as well. Among the pigments that have been used as coloring agents for emulsion inks, those that have a larger diameter than the pores on the surface of the paper, or oil or other vehicle penetrates quickly into the paper and is left behind on the paper. This is due to the fact that objects peel off due to friction between the paper and the hands of workers, and adhere to non-image areas and hands.

[0003]

In order to improve the above-mentioned inconvenience, varnish is added to the ink,
Measures have been taken to increase the fixing property between the pigment and the paper to improve the fixing property. However, even with this, the above-mentioned problems occur, and further improvement in fixability is required.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks, to maintain a good printed matter image in a rotary printing press for stencil printing, and to prevent the hand of the printed matter from being stained with the W / O type emulsion ink for stencil printing. To provide.

[0005]

The present inventor has improved the fixability of the W / O type emulsion ink without impairing the safety and storage stability of the W / O type emulsion ink and prevents the non-image area and the hand from being stained by friction. As a result of intensive studies to eliminate the above, it was found that the use of an oil-soluble dye as a colorant was found to achieve the above-mentioned object and that the image density could be increased.

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

The oil-soluble dye has a diameter remarkably smaller than that of the pigment even when it is dissolved or dispersed in a solvent. Therefore, the oil-soluble dye 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 due to friction. Therefore, W / O
By using an oil-soluble dye as a colorant in the oil phase of the type emulsion ink, the fixability can be greatly improved. Further, it is considered that the increase in image density is 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 the colorant. In particular, when 1 to 40% by weight of the oil-soluble dye is used in combination with the pigment, the excellent water resistance and light resistance of the pigment are not impaired, and other image characteristics such as show-through, see-through, and bleeding in the image are not observed. The fixing property can be improved without having the disadvantage of
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 used in combination with a pigment,
The color of the oil-soluble dye is not always the same as the color of the pigment used. The oil phase, oil-soluble dyes, pigments, resins,
It is composed of oil, dispersant, emulsifier, gelling agent, etc., and the aqueous phase is composed of water, water-soluble resin, preservative, water evaporation inhibitor, antifreezing agent, pH adjusting agent, antioxidant, electrolyte, etc. ing.

As oil-soluble dyes, butter yellow, Sudan orange RR, Sudan brown R, Sudan red B
Known oil-soluble dyes such as B, Sudan Black B, Sudan Red 3R, Sudan Violet R, Sudan Blue GL, and Sudan Green BB can be mentioned. These may be used alone or in plural. The amount used is 0.
01 to 5.00% by weight is preferable.

When an oil-soluble dye and a pigment are used in combination, examples of the pigment include azo pigments, phthalocyanine pigments, nitroso pigments, nitro pigments, vat dye pigments, mordant dye pigments, basic dye pigments, Known pigments such as acid dye-based pigments and natural dye-based pigments can be used. These may 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 pigment used is preferably 1 to 20% by weight with respect to the ink.

Examples of the pigment dispersant or the emulsifier for forming the W / O type 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 polyoxy. 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 alkylphenyl 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,
It can be used alone or in combination. The amount of the surfactant used is preferably 1 to 20% by weight based on the ink.

As the oil, known mineral oils, vegetable oils and hydrocarbon synthetic oils can be used alone or in combination. Mineral oils include petroleum solvents, spindle oils, liquid paraffin, motor oils, gear oils, machine oils, and vegetable oils such as linseed oil, tall oil, corn oil, soybean oil, castor oil, and dehydrated castor oil. Can be mentioned. These may be used alone or in combination. The amount of oil used is preferably 5 to 30% by weight with respect to the ink.

Resins are used for the purpose of improving the adhesion between ink and paper, the dispersibility of pigments, the stability of ink over time, 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 may 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 in the oil phase in order to improve ink stability and pigment dispersibility.

The water used in the water phase is tap water, purified water,
Any ion-exchanged water may be used, and the amount used is preferably 20 to 70% by weight with respect to the ink. Acrylic resin, gum arabic and the like are used as the water-soluble resin used for replenishing moisture or thickening. The amount used is preferably 1 to 15% by weight with respect to the ink.

A water-soluble organic solvent may be used in the aqueous phase in order to suppress water evaporation or prevent freezing, and examples thereof include glycols such as ethylene glycol, diethylene glycol and propylene glycol, methanol, ethanol and isopropanol. Examples include 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 with respect to the ink.

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

The oil phase is prepared by dispersing the pigment in a generally known disperser and diluting it with oil or another oil phase composition.
A known stirrer is usually used for the dilution. In the water phase,
The aqueous phase composition is usually mixed with a stirrer. The finished oil phase and water phase are easily emulsified by using a known emulsifier. The manufacturing method and means such as dispersion, dilution, and emulsification can be appropriately changed.

[0019]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. All parts shown below are based on weight.

Example 1 Sudan Black B (coloring agent) 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 paraoxybenzoate (preservative) 0.1 parts

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

Example 2 Furnace carbon black 2.7 parts Sudan black B 0.3 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 parts Water 70.8 parts Methyl paraoxybenzoate 0.1 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 500, and I.I. D
And the fixing rate was measured.

Example 3 Furnace carbon black 2.8 parts Sudan Blue GL 0.2 parts Spindle oil 15.0 parts Rosin modified phenolic resin 5.0 parts Sorbitan sesquioleate 3.7 parts Sorbitan monooleate 2.3 parts Dibutyl Hydroxytoluene 0.1 parts Water 70.8 parts Methyl paraoxybenzoate 0.1 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 500, and I.I. D
And the fixing rate was 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 parts Water 70.8 parts Methyl paraoxybenzoate 0.1 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 500, and I.I. D
And the fixing rate was measured.

Example 4 Phthalocyanine Green 4.0 parts Sudan Green BB 0.5 parts Petroleum 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 parts 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 500, and I.I. D
And the fixing rate was 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 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 500, and I.I. D
And the fixing rate was measured.

Comparative Example 2 Phthalocyanine Green 4.5 parts Petroleum 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
Printing is performed at 500, and I.I. D
And the fixing rate was measured.

Example 6 Phthalocyanine Blue 4.0 parts Sudan Blue GL 0.5 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 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 500, and I.I. D
And the fixing rate was 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 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 500, and I.I. D
And the fixing rate was measured.

Comparative Example 3 Phthalocyanine Blue 4.5 parts Petroleum 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
Printing is performed at 500, and I.I. D
And the fixing rate was measured.

Example 8 Styrontium Red 3.5 parts Sudan Red BB 0.5 part Petroleum solvent 15.0 parts Alkyd resin 5.0 parts Sorbitan sesquioleate 4.5 parts Dibutylhydroxytoluene 0.1 part Water 66. 7 parts Methyl paraoxybenzoate 0.1 parts 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 500, and I.I. D
And the fixing rate was measured.

Example 9 Styrontium Red 3.7 parts Butter Yellow 0.3 parts Petroleum 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 parts 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 500, and I.I. D
And the fixing rate was measured.

Comparative Example 4 Strontium Red 4.0 parts Petroleum 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 500, and I.I. D
And the fixing rate was measured.

Examples 1, 2, 3 and Comparative Example 1, Example 4,
5 and Comparative Example 2, Examples 6 and 7 and Comparative Example 3, Examples 8 and 9
The results of Comparative Example 4 and 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 fixability of the image and also improves the image density.

[0052]

Since the emulsion ink for stencil printing of the present invention is configured to contain an oil-soluble dye or an oil-soluble dye / pigment mixture as a colorant, it has excellent storage stability, safety and image characteristics. The fixability of the ink on the paper is improved without impairing it. This prevents the printed matter and the hand of the operator from getting dirty due to the friction of the image. Further, the emulsion ink of the present invention can increase the image density.

Claims (4)

[Claims] 1. A W / O type emulsion ink for stencil printing, comprising an oil-soluble dye as a colorant. 2. A W / O type emulsion ink for stencil printing, which comprises an oil-soluble dye / pigment mixture as a colorant. 3. The oil-soluble dye / pigment mixture contains 1 to 40% by weight of the oil-soluble dye based on the pigment.
The W / O type emulsion ink for stencil printing according to 1. 4. The W / O emulsion ink for stencil printing according to any one of claims 1 to 3, which comprises 5 to 50% by weight of an oil phase and 50 to 95% by weight of an aqueous phase. .