JP2585937B2 - Emulsion blue 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 an emulsion blue ink for stencil printing, and more particularly to an emulsion blue ink for stencil printing which is reddish blue and has excellent high-temperature storage stability.

[0002]

2. Description of the Related Art As is well known, a stencil printing method uses a stencil printing paper, and transfers ink from one side of the base paper to the other side through a perforated portion of the stencil printing paper, thereby forming a printing material such as paper. This is for printing on the surface. In recent years, the rotary stencil printing press has been automated by a microcomputer or the like, and the operation has been simplified, and accordingly, it has been demanded that a good printed matter can be obtained in various environments immediately after the start of printing.

[0003] On the other hand, storage conditions may be exposed to high temperatures, such as in a tent in summer or shipping during export, and the stability of the ink at that time is a problem. Conventionally, as a pigment of an emulsion blue ink, α-type Cu phthalocyanine blue (C.I.
Pigment Blue 15) is preferred, but there is a problem with the pigment that when used in an organic solvent system, crystal growth and transition occur, and the coloring power is reduced and the fluidity is significantly reduced. To solve this point, β-type Cu phthalocyanine blue (CI Pigment Blue) is used.
15: 3) and ε-type Cu phthalocyanine blue (C.I.
Pigment Blue 15: 6), pigment surface treatment (CI Pigment Blue 15: 2), chlorine substitution (CI Pigment Blue 15: 1), and the like. With phthalocyanine blue and chlorine substitution, the hue of the ink is replaced with yellowish blue and a vivid reddish blue cannot be obtained. Although there is no problem with respect to, there is a disadvantage that it is expensive.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the above-mentioned disadvantages of the prior art, and to provide a rotary stencil printing machine with excellent emulsion high temperature (50 to 70 ° C.) stability and reddish blue color. And to provide an emulsion blue ink for stencil printing.

[0005]

According to the present invention, there is provided a water-in-oil emulsion comprising about 10 to 50% by weight of an oil phase and about 90 to 50% by weight of an aqueous phase. An emulsion blue ink for stencil printing characterized by comprising α-type phthalocyanine blue and β-type phthalocyanine blue is provided, and in the blue ink, the content ratio of the β-type phthalocyanine blue pigment to all pigments is provided. A blue ink for stencil printing characterized by satisfying the following formula (I), further comprising a paraffinic oil as an organic solvent in the oil phase. An emulsion blue ink for stencil printing is provided. Y ≧ 100 / X + 5 (I) where Y and X represent the following numerical values. Y: ratio (%) of β-type phthalocyanine blue to all pigments used X: viscosity of organic solvent (40 ° C. cSt)

[0006] To achieve the above object, the present inventors have
As a result of various studies, the use of two specific pigments as the blue pigment in the oil phase of the water-in-oil emulsion resulted in a reddish blue color and excellent high-temperature storage stability. By setting the proportion of the pigment used in a specific range, the effect of ensuring high-temperature storage stability has been found, and a paraffinic oil has been found to be preferable as the organic solvent used. The present invention has been made based on these.

Hereinafter, the present invention will be described in more detail. The emulsion blue ink for stencil printing of the present invention has an oil phase of about 10 to
A water-in-oil emulsion comprising 50% by weight and an aqueous phase of about 90 to 50% by weight, wherein the oily phase comprises a pigment component, an organic solvent (oil component), a resin, an emulsifier, and the like. Is composed of water, electrolytes, antiseptic / antifungal agents, antioxidants, water evaporation inhibitors, water-soluble polymers and the like. Known components that do not inhibit the formation of the emulsion are used as these components.

[0008] In the emulsion blue ink of the present invention, α-type Cu phthalocyanine blue (CI Pigment Blue 15) and β-type Cu phthalocyanine blue (CI Pigmen) are used as blue pigment components in the oil phase.
t Blue 15: 3). As a result, even when dispersed in an organic solvent, a decrease in coloring power and a decrease in flow characteristics do not occur, and a reddish blue color and excellent storage stability can be obtained. Further, by setting the use ratio of the two pigments in a range satisfying the above formula (I),
The storage stability at high temperatures is more reliably improved.

As the organic solvent in the oil phase used in the present invention, a paraffinic oil is preferable. However, a commonly used organic solvent for letterpress printing, offset printing, screen printing and the like, and naphthenic oil are also used. For example, mineral oils such as liquid paraffin, spindle oil, light oil, kerosene, machine oil and lubricating oil; and vegetable oils such as olive oil, rapeseed oil, castor oil, soybean oil and the like are used. In the present invention, a synthetic oil can also be used. When using synthetic oils, various compounds are available. Representative synthetic vehicles include polyisobutylenes, hydrogenated polydecenes, trimethylolpropane esters, neopentyl and pentaerythritol esters, di (2-ethylhexyl) sebacate, di (2-ethylhexyl) adipate, dibutyl phthalate, Fluorocarbons, silicon esters, silanes, esters of phosphorus-containing acids, liquid urea, ferrocene derivatives, hydrogenated synthetic oils, linear polyphenyls, siloxanes and silicons (polysiloxanes), butyl-substituted bis Examples thereof include alkyl-substituted diphenyl ethers represented by (p-phenoxyphenyl) ethers and phenoxyphenyl ethers.

Resins are used in the oil phase for the purpose of improving the adhesion between ink and paper and the dispersibility of the pigment in the oil phase. Examples of the resin include a phenol resin, a maleic acid resin, and a petroleum oil. Resins, alkyd resins, rubber derivative resins and the like can be mentioned, and these can be used alone or in combination of two or more.

The emulsifier used in the present invention is preferably a nonionic surfactant, such as sorbitan higher fatty acid ester, polyoxyethylene sorbitan higher fatty acid ester, fatty acid monoglyceride, fatty acid diglyceride and higher alcohol, alkylphenol, fatty acid and the like. Of ethylene oxide. These emulsions are used alone or in combination of two or more having different HLB to prepare emulsions having high stability.

As the evaporation inhibitor and anticoagulant in the aqueous phase used in the present invention, polyhydric alcohols such as ethylene glycol, sorbitol and glycerin, and polyethylene glycol are used. As the antiseptic / fungicide, for example, an aromatic hydroxy compound and its chlorine compound, salicylic acid, phenolic acid, methyl p-oxybenzoate, ethyl p-oxybenzoate and the like, sorbic acid, dehydroacetic acid and the like are used.

The water-soluble polymer used in the aqueous phase includes, for example, starch, mannan, sodium alginate,
Natural polymers such as galactan, tragacanth gum, gum arabic, bullran, dextran, xanthan gum, glue, gelatin, collagen, casein; kilboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxymethylstarch, carboxymethyl Semi-synthetic polymers such as starch and dialdehyde starch; acrylic resin and acrylic resin derivatives such as sodium polyacrylate and triethanolamine polyacrylate; polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyethylene oxide, polyvinyl methyl ether, etc. Is used.

In preparing the emulsion blue ink of the present invention, the oil phase is usually prepared by dispersing the pigment using a known disperser and diluting the pigment with an organic solvent or another oil phase composition. A known stirrer is usually used for dilution. The aqueous phase is usually mixed with an aqueous phase composition using a stirrer. The completed oil phase and aqueous phase are usually using a known emulsifier,
It is easily emulsified. Production methods and means such as dispersion, dilution, and emulsification can be appropriately changed.

[0015]

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. The parts and percentages shown below are based on weight.

Example 1 Raw materials having the following formulation were used. (Pigment) α-type Cu phthalocyanine blue 4.5 parts β-type Cu phthalocyanine blue 1.5 parts (Emulsifier) Sorbitan sesquioleate 5 parts (Solvent) Paraffin oil 16 parts (Water) Deionized water 34.17 parts (Anti-freezing agent) Ethylene glycol 10.00 Part (water-soluble polymer) 1% aqueous solution of polyacrylic acid 28.00 parts (thickener) 10% aqueous solution of sodium hydroxide 0.83 part Note) Ratio of β-type Cu phthalocyanine to all pigments used: 25% Oil viscosity: 121 cSt

The pigment dispersion is prepared by milling Cu phthalocyanine blue, a paraffinic oil and a surfactant, and optionally an alkyd resin with three rolls. Accordingly, a small amount of a gel varnish such as a rosin-modified phenol resin was added, and these were uniformly mixed with a mixing stirrer to obtain an oil phase.
The aqueous phase was prepared by immersing the acrylic acid polymer in water overnight, adding ethylene glycol thereto, and then adding an aqueous solution of sodium hydroxide as a thickener with stirring to increase the viscosity. Was the aqueous phase. Next, the aqueous phase was added to the oil phase and emulsified to obtain an emulsion blue ink for stencil printing.

Examples 2 to 7 and Comparative Examples The emulsion blue ink for stencil printing was obtained in the same manner as in Example 1 with the formulation shown in Table 1. Table 1 also shows the ratio of β-type phthalocyanine to the pigments used, the type of organic solvent, and the viscosity of the organic solvent.

(Evaluation) The above inks were stored in an environment of 70 ° C., and a viscometer (manufactured by Rion) (23)
° C), and the rate of increase in viscosity was evaluated as high-temperature storage stability. Table 1 shows the results.

[0020]

[Table 1] Note) ○: Ratio of increase in viscosity after 7 days at 70 ° C is less than 1.4 times △: Ratio of increase in viscosity after 7 days at 70 ° C is 1.4 times or more and less than 2.0 times ×: Ratio of increase in viscosity after 70 days and 7 days Is 2.0 times or more and less than 2.5 times XX: The rate of increase in viscosity after 7 days at 70 ° C is 2.5 times or more

[0021]

The emulsion blue ink for stencil printing according to claim 1 contains α-phthalocyanine blue and β-phthalocyanine blue as blue pigments in the oil phase of the water-in-oil emulsion. Even when dispersed in an organic solvent, the coloring power and the fluidity do not decrease, the color is reddish blue, and the storage stability at high temperatures is excellent.

In the emulsion blue ink for stencil printing according to claim 2, since the content ratio of the β-type phthalocyanine blue pigment to all the pigments satisfies the above formula (I), the improvement in high-temperature storage stability can be further improved. The effect of ensuring is added.

The emulsion blue ink for stencil printing according to claim 3 contains a paraffinic oil as an organic solvent in the oil phase, so that the effect of further improving high-temperature storage stability is added. .

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Ota Shimada, Shimada-cho, Shibata-gun, Miyagi Prefecture No. 3 1 Tohoku Ricoh Co., Ltd. (72) Inventor Keisuke Asada Shimada, Shibata-cho, Miyagi Jinmyodo 3 No. 1 Tohoku Ricoh Co., Ltd. (56) References JP-A-4-132777 (JP, A) JP-A-2-20976 (JP, A)

Claims (3)

(57) [Claims] An oil phase of about 10 to 50% by weight and an aqueous phase of about 90 to 90% by weight.
50% by weight of a water-in-oil emulsion,
In addition, an emulsion blue ink for stencil printing, characterized by containing α-type phthalocyanine blue and β-type phthalocyanine blue as blue pigments in the oil phase. 2. The emulsion blue ink for stencil printing according to claim 1, wherein the content ratio of the β-type phthalocyanine blue pigment to all the pigments satisfies the following formula (I). Y ≧ 100 / X + 5 (I) where Y and X represent the following numerical values. Y: ratio (%) of β-type phthalocyanine blue to all pigments used X: viscosity of organic solvent (40 ° C. cSt) 3. The emulsion blue ink for stencil printing according to claim 1, wherein a paraffin-based oil is contained as an organic solvent in the oil phase.