JP4845421B2 - Emulsion ink for stencil printing - Google Patents

Description

  The present invention is a water-in-oil type (W / O type) that does not increase in viscosity even during high temperature storage, does not cause separation and alteration of ink, and does not generate harmful substances when incinerated. The present invention relates to an emulsion ink for stencil printing.

  As is well known, a stencil printing method uses a stencil printing paper (stencil) having a perforated portion, and moves the ink from one side of the stencil to the other side through the perforated portion of the stencil, so that the paper This is a method for printing on the surface of a substrate. This stencil printing method is usually a water-in-oil type (W / O type) containing a volatile solvent, a non-volatile solvent, a resin, a colorant, a surfactant, water, an antifreezing agent, an electrolyte, and a preservative. The emulsion ink is used.

  In such an emulsion ink for stencil printing, for example, C.I. I. Pigment Green 7, C.I. I. A phthalocyanine green pigment such as Pigment Green 36 is used (see Patent Document 1).

  However, a water-in-oil (W / O) emulsion ink using a phthalocyanine-based green pigment has a problem that the viscosity of the ink increases when exposed to high temperatures such as in a warehouse or a car interior. there were. Further, there has been a problem that the ink is separated and deteriorated and the desired print quality cannot be obtained. In addition, phthalocyanine-based green pigments contain halogen components such as chlorine and bromine in the molecule, so if the printed sample is not incinerated by appropriate equipment, it can generate harmful substances such as dioxins. It has sex.

  Therefore, as a water-in-oil (W / O) stencil printing emulsion ink that can be colored at least in green, the viscosity does not increase even during high-temperature storage, and the ink does not undergo separation and alteration. In addition, water-in-oil type (W / O type) emulsion inks for stencil printing that do not generate harmful substances when incinerated have not been obtained, and it is desired to provide them promptly. .

JP 2000-53903 A

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention is a water-in-oil type (W / O type) emulsion ink for stencil printing that can be colored at least in green. In addition, an object of the present invention is to provide a water-in-oil type (W / O type) stencil printing emulsion ink that does not generate toxic substances when incinerated.

Means for solving the problems are as follows. That is,
<1> 10 to 90% by mass of an oil phase and 90 to 10% by mass of an aqueous phase, containing a colorant in at least one of the oil phase and the aqueous phase, and the colorant being a blue colorant and a yellow colorant An emulsion ink for stencil printing comprising a colorant. In the emulsion ink for stencil printing according to <1>, since the green colorant can be colored with a blue colorant and a yellow colorant without using a green colorant, the green colorant has, It is possible to prevent the occurrence of problems such as an increase in viscosity during storage at a high temperature and separation and alteration of ink.
<2> The emulsion ink for stencil printing according to <1>, wherein the colorant does not contain a halogen component. In the emulsion ink for stencil printing described in <2>, since the colorant does not contain a halogen component, generation of harmful substances can be prevented during incineration.
<3> The emulsion ink for stencil printing according to any one of <1> to <2>, wherein the blue colorant is a phthalocyanine pigment having a β-type crystal structure. In the emulsion ink for stencil printing described in <3>, since the blue colorant is a phthalocyanine pigment having a β-type crystal structure, a stable ink can be obtained even at a higher temperature.
<4> The emulsion ink for stencil printing according to any one of <1> to <3>, wherein the yellow colorant is at least one selected from a quinolinoquinolone pigment, a fluoroflavin pigment, and a fluorvin pigment. is there.

  According to the present invention, various problems in the prior art can be solved, and in a water-in-oil (W / O) emulsion ink for stencil printing that can be colored at least in green, the viscosity increases even during high-temperature storage. In addition, a water-in-oil type (W / O type) emulsion ink for stencil printing that does not cause separation and alteration of ink and does not generate harmful substances when incinerated can be provided.

  The emulsion ink for stencil printing of the present invention comprises 10 to 90% by mass of an oil phase and 90 to 10% by mass of an aqueous phase, contains a colorant in at least one of the oil phase and the aqueous phase, and the colored The agent comprises a blue colorant and a yellow colorant, and further contains other components as necessary.

The emulsion ink for stencil printing contains 10 to 90% by mass of an oil phase and 90 to 10% by mass of an aqueous phase, preferably 20 to 50% by mass of an oil phase and 50 to 80% by mass of an aqueous phase.
If the mixing ratio of the oil phase is less than 10% by mass, it may not be possible to take the form of a W / O emulsion, and if it exceeds 90% by mass, the physical properties of the W / O emulsion are insufficiently effective. May end up.

<Oil phase>
There is no restriction | limiting in particular as said oil phase, According to the objective, it can select suitably, A coloring agent, an oil component, an emulsifier, resin, a dispersing agent, a gelling agent, antioxidant, an extender, Furthermore, as needed And other components.

-Colorant-
The colorant comprises a blue colorant and a yellow colorant, which may be pigments or dyes, but are preferably pigments from the viewpoint of weather resistance.

--Blue colorant--
There is no restriction | limiting in particular as said blue colorant, Although it can select suitably according to the target hue, The thing which does not contain a halogen component from a viewpoint which does not generate | occur | produce harmful substances, such as a dioxin, is preferable.
Suitable examples of such blue colorants include phthalocyanine pigments.
The phthalocyanine pigment is not particularly limited and may be appropriately selected depending on the purpose. It may be a metal such as Cu, Ni, Co, or Fe, or may be a metal-free one. The metal is preferably Cu.
There is no restriction | limiting in particular as a crystal structure (crystal type) of the said phthalocyanine pigment, According to the target hue, it can select suitably, For example, alpha type, beta type, epsilon type etc. are mentioned. Among these, β type is preferable from the viewpoint of stability and cost in a high temperature environment.
Preferable specific examples of the β-type phthalocyanine pigment include C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15: 4, and the like.
Specific examples of phthalocyanine pigments other than β-type include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 5, C.I. I. Pigment Blue 15: 6, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Blue 64, C.I. I. Pigment Blue 66, and the like.

--Yellow colorant--
The yellow colorant is not particularly limited and may be appropriately selected depending on the target hue. For example, a disazo yellow pigment, a benzimidazolone pigment, an isoindrian pigment, a flavanzuron pigment, an anthra pigment Examples include pyrimidine pigments, anthraquinone pigments, quinolinoquinolone pigments, fluoroflavin pigments, and fluorvin pigments. Among these, those not containing a halogen component are preferable from the viewpoint of preventing generation of harmful substances such as dioxins.
Preferred examples of such a yellow colorant include quinolinoquinolone pigments, fluoroflavin pigments, and fluorvin pigments.
Preferred examples of the yellow colorant include C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 4, C.I. I. Pigment Yellow 5, C.I. I. Pigment Yellow 9, C.I. I. Pigment Yellow 24, C.I. I. Pigment Yellow 42, C.I. I. Pigment Yellow 61, C.I. I. Pigment Yellow 62, C.I. I. Pigment Yellow 65, C.I. I. Pigment 74, C.I. I. Pigment 100, C.I. I. Pigment 101, C.I. I. Pigment 104, C.I. I. Pigment 117, C.I. I. Pigment 120, C.I. I. Pigment 123, C.I. I. Pigment 129, C.I. I. Pigment 133, C.I. I. Pigment 139, C.I. I. Pigment 147, C.I. I. Pigment 148, C.I. I. Pigment 151, C.I. I. Pigment 155, C.I. I. Pigment 168, C.I. I. Pigment 169, C.I. I. Pigment 175, C.I. I. Pigment 180, C.I. I. Pigment 181, C.I. I. Pigment 182, C.I. I. Pigment 185, C.I. I. Pigment 192, C.I. I. Pigment 194, quinolinoquinolone, fluoroflavin, fluorvin, and the like.

The blending ratio of the blue colorant and the yellow colorant is not particularly limited and can be appropriately adjusted according to the target green hue, but in terms of weight ratio, blue colorant: yellow colorant = 90: 10-10. : 90 is preferable, and 70:30 to 20:80 is more preferable.
The colorant can be added to the water phase as well as the oil phase. There is no restriction | limiting in particular in the addition amount in the said emulsion ink for stencil printing of the said coloring agent, According to the objective, it can select suitably, 0.1-15 mass% is preferable, and 2-8 mass% is more preferable.

-Oil component-
There is no restriction | limiting in particular as said oil component, According to the objective, it can select suitably from a well-known thing, Mineral oil, vegetable oil, etc. are mentioned.

The mineral oil is not particularly limited and can be appropriately selected according to the purpose. For example, paraffinic oil, naphthenic oil, petroleum solvent, spindle oil, liquid paraffin, light oil, kerosene, machine oil, gear Oils, lubricating oils, motor oils and the like can be mentioned. Among these, paraffinic oils, naphthenic oils, and petroleum solvents are particularly preferable.
Commercially available products can be used as the paraffinic oil, for example, Gargo Oil Arctic series manufactured by Mobil Oil Co., Nippon Oil Super Oil Series manufactured by Nippon Oil Corporation, Diana Process Oil manufactured by Idemitsu Kosan Co., Ltd. And Diana Fresia series.
The naphthenic oil has a naphthene component carbon content (CN) of 30% or more by ring analysis, an aromatic component carbon content (CA) of 20% or less, and a paraffin component carbon content. A quantity (CP) of 55% or less is suitable, for example, Gargo Oil Arctic Oil 155 and 300ID manufactured by Mobil Oil, Gargo Oil Arctic Oil Light, Gargo Oil Arctic Oil C Heavy; The company's Diana Process Oil, Diana Fresia Series; Nippon San Oil Co., Ltd.
Commercially available products can be used as the petroleum-based solvent, for example, Isopar series (C, E, G, H, L, M, etc.) and Exol (D30, D40, D80, D110, manufactured by Exxon Chemical Co., Ltd.) D130 etc.); AF solvent series (No. 4, No. 5, No. 6, No. 7, etc.) manufactured by Nippon Oil Corporation.

When considering the stability of the ink, these mineral oils preferably use those having a polycyclic aromatic component that is an aromatic hydrocarbon containing three or more condensed aromatic rings of less than 3% by mass. . Further, the mutagenicity index (MI) is less than 1.0, the aroma content (% C _A ) is 20 to 55%, the aniline point is 100 ° C. or less, and benzo [a] anthracene based on the total mass of the oil, The content of polycyclic aromatics such as benzo [b] fluoranthene, benzo [j] fluoranthene, benzo [k] fluoranthene, benzo [a] pyrene, dibenzo [a, j] acridine is 10 ppm or less and total content The amount is 50 ppm or less.
Note that a highly safe aroma oil (for example, JP-A-11-80640) can be used as necessary.

  There is no restriction | limiting in particular in the addition amount in the said emulsion ink for stencil printing of the said mineral oil, According to the objective, it can select suitably, 5-50 mass% is preferable and 15-30 mass% is more preferable.

Examples of the vegetable oil include soybean oil, corn oil, sunflower oil, rapeseed oil, safflower oil, sesame oil, castor oil, dehydrated castor oil, camellia oil, olive oil, palm oil, rice oil, cottonseed oil, palm oil, linseed oil, Examples include palm kernel oil, tung oil, camelia oil, grape seed oil, sweet almond oil, pistachio nut oil, jojoba oil, macadamia nut oil, and mead home oil. These may be used alone. Two or more kinds may be used in combination.
Examples of the esterified vegetable oil include those obtained by esterifying the vegetable oil. Examples of the ester include methyl ester, ethyl ester, and butyl ester. Examples of the esterified vegetable oil include esterified soybean oil and esterified tall oil.
As the alkyd resin, the soybean oil fatty acid alkyd resin whose fat is soybean oil is used, and by using esterified soybean oil, the total of the components derived from soybean oil exceeds 6%. This is also advantageous in terms of safety.
Moreover, waste edible oil can also be used as a raw material of the esterified vegetable oil.
The waste cooking oil is not particularly limited as long as it can be regenerated with the vegetable oil after use, but examples include those obtained by recovering the vegetable oil used for the production of tempura etc. in restaurants, school lunches, prepared dishes, etc. It is done.

  The addition amount of the vegetable oil in the emulsion ink for stencil printing is preferably 5 to 20% by mass.

-Emulsifier-
The emulsifier is not particularly limited as long as it can form a water-in-oil emulsion and can be appropriately selected according to the purpose, but a nonionic surfactant is particularly preferable. Examples of the nonionic surfactant include sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, pentaerythritol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbite fatty acid ester, polyoxy Ethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene phytosterol ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, poly Oxyethylene lanolin derivatives, polyoxyethylene alkyl amines Emissions, polyoxyethylene fatty acid amides, polyoxyethylene alkylphenyl formaldehyde condensates, and the like, which may be used alone or in combination of two or more thereof. When using 2 or more types together, it is preferable to adjust a highly stable emulsion by combining those having different HLB values.
There is no restriction | limiting in particular in the addition amount in the said emulsion ink for stencil printing of the said emulsifier, According to the objective, it can select suitably, 1-8 mass% is preferable, and 2-5.5 mass% is more preferable.

-Resin-
The resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, alkyd resin, rosin; polymerized rosin, hydrogenated rosin, rosin ester, rosin polyester resin, hydrogenated rosin Rosin resins such as esters; Rosin-modified alkyd resins, rosin-modified maleic resins, rosin-modified resins such as rosin-modified phenol resins; maleic resins; phenol resins; petroleum resins; rubber derivative resins such as cyclized rubbers; Polymerized castor oil and the like can be mentioned, and these may be used alone or in combination of two or more. Among these, alkyd resins are particularly preferable.

The weight average molecular weight of the resin is preferably 8000 to 160,000, more preferably 30,000 to 80,000, from the viewpoint of fixability and printability.
The addition amount of the resin in the oil phase is preferably 2 to 50% by mass and more preferably 5 to 20% by mass from the viewpoint of the cost of the ink and printing suitability.
When the weight average molecular weight of the resin is low and when the addition amount is small, the effect on fixability may be small, while when the weight average molecular weight is too high or the addition amount of the resin is large, the ink In some cases, the viscosity becomes high, and printability problems such as ink leakage from the rear end of the drum may occur.
Commercially available products can be used as the resin, and KG-836, KG-846, KG-1801, KG-1832, KG-1829, KG-1804, KG-1828, KG- manufactured by Arakawa Chemical Industries, Ltd. 1808-1, KG-1834, KG-1831, KG-1833, Tamanol 353, Tamanol 403, Tamanol 371, Tamanol 394; Hariphenol (561, 564, 582, 173, T3120, T3040, P637, manufactured by Harima Chemical Co., Ltd.) In addition, cyclized rubber is also effective for fixing properties, for example, trade names ALSYNOL RS47, ALSYNOL RS44, SYNTEX 800 manufactured by Colombian Carbon Japan, and ALPEX CK 450, ALPEX CK514 manufactured by Hoechst. Etc.

The said alkyd resin is normally comprised from fats and oils, a polybasic acid, and a polyhydric alcohol. Examples of the fats and oils include coconut oil, palm oil, olive oil, castor oil, rice bran oil, cottonseed oil, soybean oil, linseed oil, and tung oil. Among these, soybean oil is particularly preferable. As the polybasic acid, either a saturated polybasic acid or an unsaturated polybasic acid can be used. Examples of the saturated polybasic acid include phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, tetrahydrophthalic acid and the like. Examples of the unsaturated polybasic acid include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic anhydride, and the like.
Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, glycerin, trimethylolpropane, neopentyl glycol, diglycerin, triglycerin, and pentaerythritol. Examples include slits, dipentaery slits, mannits, and sorbits.

The alkyd resin has an acid value of 15 or less, and more preferably 10 or less. The iodine value is preferably 120 or less. Moreover, the oil length of the said alkyd resin is represented by the mass% in resin when the fatty acid in the said fats and oils exists with a triglyceride, and 60-90 mass% is preferable normally. The weight average molecular weight of the alkyd resin is preferably 30,000 or less, and more preferably 10,000 or less.
Here, the acid value of the alkyd resin can be measured, for example, according to JIS K0070. The iodine value of the alkyd resin can be measured, for example, according to JIS K0070.

-Dispersant-
As the dispersant, those which are dissolved in each of the oil phase and the water phase and have a surface activity and do not inhibit the formation of the emulsion can be used. Nonionic surfactant for emulsifier and water-soluble polymer described later Compounds can also be used as dispersants.
The dispersant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include sodium di (2-ethylhexyl) sulfosuccinate (OTP-75, manufactured by Nikko Chemicals Co., Ltd.), alkylamine polymers. Compound, aluminum chelate compound, styrene-maleic anhydride copolymer polymer compound, polyglycerin fatty acid ester compound, polyesteramine compound, polycarboxylic acid ester type polymer compound, aliphatic polycarboxylic acid, polymer Polyester amine salts, ester type anionic surfactants, long chain amine salts of high molecular weight polycarboxylic acids, salts of long chain polyaminoamides and high molecular acid polyesters, polyamide compounds, phosphate ester surfactants, alkylsulfocarboxylic acids Salts: N such as polyisopropylacrylamide -Alkyl-substituted acrylamide polymers or copolymers thereof, α-olefin sulfonates, dioctyl sulfosuccinates, polyethyleneimine, alkylolamine salts, acetylenic diol compounds, orioxyethylene nonylphenyl ether, polyoxyethylene alkylamines , Polyoxyethylene alkyl ether, and the like. In addition to these, ionic surfactants and amphoteric surfactants can be used as long as they do not impair the storage stability of the ink. These may be used alone or in combination of two or more. May be used in combination. Among these, polyesteramine compounds are particularly preferable.

The polyesteramine compound is a reaction product of a polyester having a free carboxylic acid group and a poly (low alkylene) imine, has at least two polyester chains, and each of the polyester chains has a poly (low alkylene) imine chain. Is a compound to which is bound.
Examples of the polyesteramine-based compound include Lubrizol Solspurs described in British Patent Application Publication No. 2001083.

  Further, when the pigment added to the aqueous phase is a phthalocyanine pigment, it is more preferable to use a phthalocyanine sulfonic acid dispersant (for example, Solsperz 5000) substituted with ammonium.

  Commercially available products can be used as the dispersant, for example, Plenact AL-M, Ajisper PN411 (manufactured by Ajinomoto Fine Techno Co., Ltd.), Solspers series 5000, 13940, 16000, 17000, 20000, 28000, 54000 (Lublizol). Etc.). These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular in the addition amount of the said dispersing agent, According to the objective, it can select suitably, 40 mass parts or less are preferable with respect to 100 mass parts of coloring agents, and 0.1-35 mass parts is more preferable. When the addition amount exceeds 40 parts by mass, the emulsion stability of the ink may be affected, and the cost may increase.

-Gelling agent-
The gelling agent has a role of improving the storage stability, fixability, fluidity, etc. of the ink by gelling the resin contained in the oil phase, and is preferably a compound that coordinates with the resin in the oil phase. . Examples of the gelling agent include organic acid salts containing organic metals such as Li, Na, K, Al, Ca, Co, Fe, Mn, Mg, Pb, Zn, and Zr, organic chelate compounds, and metal soap oligomers. Can be mentioned. Specifically, octylic acid metal salts such as aluminum octylate, naphthenic acid metal salts such as manganese naphthenate, stearates such as zinc stearate, organic chelate compounds such as aluminum diisopropoxide monoethyl acetoacetate, etc. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the addition amount of the said gelatinizer, According to the objective, it can select suitably, 15 mass% or less is preferable with respect to the total amount of resin in an oil phase, and 5-10 mass% is more preferable.

-Antioxidant-
The antioxidant is not particularly limited and can be appropriately selected from known ones. For example, nordihydroguaiaretic acid (NDGA), citrate ester, extracted tocopherol, tocopherol, butylhydroxytoluene , Gallic acid, dibutylhydroxytoluene, propyl gallate, butylhydroxyanisole, sulfites, thiosulfate, ascorbic acid, ascorbate, ascorbic acid derivatives and the like, and these may be used alone. Two or more kinds may be used in combination.
The amount of the antioxidant added to the oil phase is preferably 2% by mass or less, and more preferably 0.01 to 1.0% by mass.

-Extender pigment-
The extender pigment can be added to the oil phase, the aqueous phase, or both phases for preventing bleeding and adjusting the viscosity in the ink, and either inorganic fine particles or organic fine particles are preferable. Examples of the inorganic fine particles include clay, silica, talc, clay, calcium carbonate, barium sulfate, titanium oxide, alumina white, diatomaceous earth, kaolin, mica, and aluminum hydroxide. Examples of the organic fine particles include polyacrylate resin, polyurethane resin, polyester resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polysiloxane resin, phenol resin, epoxy resin, or these A copolymer, and the like.
There is no restriction | limiting in particular in the addition amount in the said emulsion ink for stencil printing of the said extender, According to the objective, it can select suitably, 0.1-50 mass% is preferable, and 1-5 mass% is more preferable.

<Water phase>
The aqueous phase is water, an electrolyte, and if necessary, a water-soluble polymer compound, an O / W resin emulsion, an antiseptic or fungicide, a water evaporation inhibitor or an antifreeze agent, a pH adjuster, etc. It contains other components.

  If it is clean, there will be no restriction | limiting in particular if it is clean, According to the objective, it can select suitably, For example, a tap water, ion-exchange water, distilled water etc. can be used.

-Electrolyte-
The electrolyte is added to increase the stability of the emulsion, and it is preferable to add an electrolyte composed of ions having a high liquid separation permutation effective for improving the stability of the emulsion. Anions having a high liquid separation permutation are citrate ions, tartaric acid ions, sulfate ions, acetate ions, and the like. Cations having a high liquid separation permutation are alkali metal ions and alkaline earth metal ions. The electrolyte added here is preferably a salt in which at least one of an anion and a cation is composed of the above ions, such as magnesium sulfate, sodium sulfate, sodium citrate, sodium hydrogen phosphate, sodium borate, sodium acetate, etc. Is mentioned. Among these, a divalent anion-containing compound is preferable, and magnesium sulfate is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.
The amount of the electrolyte added in the aqueous phase is, for example, preferably 0.01 to 2% by mass, and more preferably 0.5 to 1.5% by mass.

-Water-soluble polymer compounds-
The water-soluble polymer compound may be added for the purpose of moisturizing, thickening, dispersing colorants and extender pigments, improving drying after printing, and the like.
The water-soluble polymer compound is not particularly limited and may be appropriately selected from known compounds according to the purpose. Examples thereof include natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds. Can be mentioned.
Examples of the natural polymer compound include starch, mannan, sodium alginate, galactan, tragacanth gum, gum arabic, pullulan, dextran, xanthan gum, glue, gelatin, collagen, casein, and the like.
Examples of the semisynthetic polymer compound include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxymethyl starch, carboxymethyl starch, and dialdehyde starch.
Examples of the synthetic polymer compound include neutralized products such as acrylic acid resin and sodium polyacrylate; polyvinyl imide, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene imine, polyacrylamide, poly N-acryloyl pyrrolidine, poly N-isopropyl. Poly N-alkyl substituted acrylamides such as acrylamide; polyethylene oxide, polyvinyl methyl ether, styrene-maleic anhydride copolymer, styrene-acrylic acid copolymer, or polymers in which these are partially hydrophobic with alkyl groups, etc. Is mentioned.
The acrylamide polymer and the acrylic polymer may be a copolymer type polymer in which a substituent is partially hydrophobized with an alkyl group. Further, it may be a block copolymer of polyethylene and polypropylene or polybutylene. These water-soluble polymer compounds may be used alone or in combination of two or more.
The addition amount of the water-soluble polymer compound in the aqueous phase is preferably 25% by mass or less, and more preferably 0.5 to 15% by mass.

-Oil-in-water (O / W) resin emulsion-
The oil-in-water (O / W) resin emulsion may be added for the same purpose as the water-soluble polymer compound.
The oil-in-water (O / W) resin emulsion is not particularly limited and may be appropriately selected from known ones, and may be a synthetic polymer compound or a natural polymer compound. Examples of the synthetic polymer compound include vinyl acetate resin, acrylic ester resin, methacrylic ester resin, vinyl chloride resin, ethylene-vinyl acetate copolymer, vinyl acetate-acrylic ester copolymer, styrene-acrylic acid. Examples thereof include ester copolymers, vinylidene chloride-acrylic acid ester copolymers, vinyl chloride-vinyl acetate copolymers, and urethane resins. Examples of the natural polymer compound include a polymer compound that can be added to an oil phase commonly used in emulsion inks for stencil printing. These may be used individually by 1 type and may use 2 or more types together.
Further, the dispersion method of the oil-in-water resin emulsion is not particularly limited, and a dispersant, a protective colloid, and a surfactant may be added, or may be synthesized by soap-free emulsion polymerization. There is no restriction | limiting in particular in the minimum film forming temperature of the said oil-in-water resin emulsion, According to the objective, it can select suitably, 40 degrees C or less is preferable.

-Preservatives or fungicides-
The preservative or fungicide is added to prevent bacteria and fungi from growing in the emulsion, and is effective when the emulsion is stored for a long period of time. The antiseptic or fungicide is not particularly limited and may be appropriately selected from known ones. Examples include salicylic acid, phenols, methyl p-oxybenzoate, and ethyl p-oxybenzoate. An aromatic hydroxy compound such as the above or a chlorine compound thereof, sorbic acid, dehydroacetic acid and the like may be mentioned, and these may be used alone or in combination of two or more.
The amount of the preservative or fungicide added to the aqueous phase is preferably 3% by mass or less, and more preferably 0.1 to 1.2% by mass.

-Preservatives or fungicides-
There is no restriction | limiting in particular as said antiseptic | preservative or antifungal agent, Although it can select and use suitably from well-known things, For example, a lower saturated monohydric alcohol, glycol, a polyhydric alcohol etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. The water evaporation inhibitor and the antifreezing agent can be used in combination.
Examples of the lower saturated monohydric alcohol include methanol, ethanol, isopropanol, butanol, isobutanol and the like. Examples of the glycol include ethylene glycol, diethylene glycol, and propylene glycol. Examples of the polyhydric alcohol include glycerin and sorbitol.
Among these, it is possible to use a water-soluble organic solvent or a polyhydric alcohol such as glycerin having a boiling point of 220 ° C. or higher, preferably 280 ° C. or higher, in order to prevent the colorant from being dried and fixed on the printing press. preferable.
1-15 mass% is preferable, as for the addition amount in the said water phase of the said water-soluble organic solvent, 4-12 mass% is more preferable, and 5-9 mass% is especially preferable.

-PH adjuster-
There is no restriction | limiting in particular as said pH adjuster, Although it can select and use suitably from well-known things, For example, a triethanolamine, sodium acetate, a triamylamine etc. are mentioned suitably. These pH adjusters can be added as necessary to maintain the pH of the aqueous phase at 6-8. If the pH of the aqueous phase deviates from the above range, the effect may be impaired when a water-soluble polymer compound is added.

  In the emulsion ink for stencil printing of the present invention, wax can be added to the oil phase in order to improve separation between the printing paper and the printing drum during printing, or to prevent the printing paper from rolling up. In addition, it is possible to further increase the viscosity by adding triethanolamine, sodium hydroxide, or the like to the aqueous phase and adding a water-soluble polymer compound. Furthermore, a rust preventive agent or an antifoaming agent can be added to the water phase to prevent the printing press from being rusted by ink or causing ink to foam. These additives may be added as necessary to known products added to emulsion inks for stencil printing, and the amount added may be the same as that of conventional products.

-Manufacturing method-
The method for producing the emulsion ink for stencil printing of the present invention is not particularly limited and can be appropriately selected from known methods according to the purpose. For example, the oil phase and the aqueous phase liquid are previously prepared by a conventional method. It can be prepared by separately preparing, adding an aqueous phase to the oil phase, and emulsifying in a known emulsifier such as a disper mixer, a homomixer, or a high-pressure homogenizer.
Specifically, a colorant, an oil component, a dispersant, a resin, and an emulsifier are mixed and stirred with a high-speed dissolver. Then, an oil phase is prepared by performing a dispersion treatment using a three-roll or bead mill (LMZ2, manufactured by Ashizawa Finetech Co., Ltd.). On the other hand, a colorant, a water-soluble polymer compound, a dispersant, an antifreezing agent, and a preservative are mixed, and this mixed solution is well dissolved in water to prepare an aqueous phase. Next, an emulsion ink for stencil printing can be produced by using an emulsifier and gradually adding and emulsifying the aqueous phase liquid while charging the oil phase liquid and stirring the liquid.
The emulsion ink for stencil printing of the present invention preferably has a viscosity of 3 to 40 Pa · s, more preferably 10 to 30 Pa · s at a shear rate of 20 sec ⁻¹ .

-Application-
As described above, the emulsion ink for stencil printing of the present invention is a water-in-oil (W / O type) stencil printing emulsion ink that can be colored at least in green, and has a viscosity even during high-temperature storage. It does not increase, does not cause separation and alteration of ink, and does not generate harmful substances when incinerated. Therefore, it is suitably used for stencil printing by a rotary stencil printing machine, for example.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

( Reference Example 1)
-Preparation of emulsion ink for stencil printing-
First, a colorant, an oil component, a dispersant, a resin, and an emulsifier were mixed according to the formulation shown in Table 1, and stirred with a high-speed dissolver. Thereafter, a dispersion process was performed using a bead mill (LMZ2, manufactured by Ashizawa Finetech Co., Ltd.) to prepare an oil phase.
Next, a coloring agent, a water-soluble polymer, a dispersing agent, an antifreezing agent, and a preservative were mixed according to the formulation shown in Table 1, and this mixed solution was dissolved well in water to prepare an aqueous phase.
Subsequently, using the emulsifier (Nikko Chemicals make, an emulsification tester ET-3A type), the said water phase liquid was gradually added, charging the said oil phase liquid and stirring the liquid. Thus, the emulsion ink for stencil printing of Example 1 was produced.

(Examples 2-3 and Reference Examples 4-6 )
-Preparation of emulsion ink for stencil printing-
Reference Example 1, except for changing the composition shown in Table 1 and Table 2, in the same manner as in Reference Example 1 to prepare a stencil printing emulsion ink of Example 2-3 and Reference Example 4-6.

(Comparative Example 1)
-Preparation of emulsion ink for stencil printing-
The emulsion ink for stencil printing of Comparative Example 1 was produced in the same manner as in Reference Example 1, except that the composition shown in Table 2 was changed to that in Reference Example 1.

  Next, each obtained stencil printing emulsion ink was subjected to a high temperature storage test as follows. The results are shown in Table 3.

<High temperature storage test>
(1) Increase in viscosity After storing the ink for 45 days at 60 ° C for one week, the three-stage evaluation shows that the increase in viscosity is 1 compared to the viscosity before storage. Evaluation was made with 2 as the sample, and 3 when the viscosity was not increased.

(2) Stability In the same manner as in (1), after storage for 45 days, in a three-stage evaluation, 1 shows a remarkable ink separation and alteration compared to the viscosity before storage, and 1 shows a slight separation and alteration of the ink. What was seen was evaluated as 2, and those where no separation and alteration of the ink were observed were evaluated as 3.

表３の結果から、比較例１は、緑色着色剤を含有しているので、粘度上昇やインキの分離変質が起こりやすいことが認められる。また、ハロゲン成分を含むので、燃焼時にダイオキシン等の有害物質が発生する虞がある。
これに対し、実施例２〜３及び参考例１、４〜６は、比較例１に比べて、粘度上昇やインキの分離変質が起こりにくいことが認められる。特に、青色着色剤がβ型の結晶構造のフタロシアニン系顔料である実施例２〜３及び参考例１及び５では、粘度上昇及びインキの分離変質の少なくともいずれかが、より起こりにくいことが認められる。また、ハロゲン成分を含まないので、燃焼時にダイオキシン等の有害物質が発生する虞もない。

From the results in Table 3, it can be seen that Comparative Example 1 contains a green colorant, so that viscosity increase and ink separation and alteration are likely to occur. Moreover, since a halogen component is contained, there exists a possibility that harmful substances, such as dioxin, may generate | occur | produce at the time of combustion.
On the other hand, it is recognized that Examples 2 to 3 and Reference Examples 1 and 4 to 6 are less likely to cause an increase in viscosity and ink separation and alteration than Comparative Example 1. In particular, in Examples 2 to 3 and Reference Examples 1 and 5 in which the blue colorant is a phthalocyanine pigment having a β-type crystal structure, it is recognized that at least one of an increase in viscosity and separation and alteration of ink is less likely to occur. . Further, since it does not contain a halogen component, there is no possibility that harmful substances such as dioxins are generated during combustion.

The emulsion ink for stencil printing of the present invention is a water-in-oil type (W / O type) emulsion ink for stencil printing that can be colored at least in green, the viscosity does not increase even during high-temperature storage, and Since it does not cause separation and alteration of ink and does not generate harmful substances when incinerated, it is suitably used for stencil printing by a rotary stencil printing machine, for example.

Claims (3)

Oil phase 10-90% by weight and comprises an aqueous phase 90 to 10 wt%, a colorant that does not contain halogen oil phase, and Ri colorant is Do blue colorant and a yellow colorant, The blue colorant is a phthalocyanine pigment having a β-type crystal structure, and the yellow colorant is C.I. I. Pigment Yellow 167 and C.I. I. A emulsion ink for stencil printing , comprising at least one of Pigment Yellow 180 . The emulsion ink for stencil printing according to claim 1, comprising 20 to 50% by mass of an oil phase and 50 to 80% by mass of an aqueous phase. The emulsion ink for stencil printing according to any one of claims 1 to 2, comprising 0.1 to 15% by mass of a colorant.