JP2006077125A - Mimeograph printing emulsion ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mimeograph printing emulsion ink excellent in chalking properties, without causing formation of stains by rolls in case of double-sided printing, excellent in starting-up properties, when ink is allowed to stand in a drum for a long period, scarcely causing separation of an oil from the ink, and excellent in environmental adaptation. <P>SOLUTION: This mimeograph printing emulsion ink contains an oily phase in an amount of 10-90 mass% and an aqueous phase in an amount of 90-10 mass%, wherein an alkyd resin having an acid value of not more than 15 and an iodine value of more than 80 is contained in the oily phase and polyvinyl pyrrolidone is contained in the aqueous phase. An embodiment in which the alkyd resin is contained in the ink in an amount of 1-7 mass%, an embodiment in which the polyvinyl pyrrolidone has a K-value of 15-30, and an embodiment in which the polyvinyl pyrrolidone is contained in the ink in an amount of 0.2-1.0 mass% as a solid concentration are provided, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is free of roller trace stains during double-sided printing, has excellent choking properties, has little oil separation from the ink, has excellent start-up properties when the ink is left in the drum for a long time, and has excellent environmental properties 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. In this stencil printing method, 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 an antiseptic is conventionally used. ) Emulsion ink.

In recent years, from the viewpoint of protecting resources such as paper, demand for double-sided printing has also increased for stencil printing machines, and drying by forced energy (ultraviolet rays (UV) and heat) from the outside is not common, and penetration In a stencil printing machine in which the dry fixing method is general, the occurrence of stains (roller stains) due to rollers during double-sided printing is one of the major problems.
For this reason, for example, (1) a method of adding aluminum chelates to the oil phase (see Patent Document 1), (2) an alkyd resin having an iodine value of 80 or less, and an aluminum chelate compound, Have been proposed (see Patent Document 2), and (3) a method of adding a water-soluble polymer compound containing a tertiary amine in the aqueous phase (see Patent Document 3).
However, according to Patent Document 1, only the effect of improving the penetrability by improving the dispersibility of the pigment is obtained, and thus the effect on the roller trace stain is insufficient. Moreover, according to the said patent document 2, although the alkyd resin is used, the iodine value is 80 or less, and also in this case, the effect with respect to roller trace stains is insufficient. Furthermore, in Patent Document 3, although 1 to 20% by mass of polyvinylpyrrolidone is contained in the aqueous phase, an oil-soluble resin having a high iodine value cannot be mixed in the oil phase, so that it remains against strong forces such as an eraser. There is a problem that the property (choking property) is insufficient.

  Therefore, (1) no smearing due to rollers during double-sided printing, (2) excellent persistence (choking) against strong force such as eraser, (3) little oil separation from ink, and (4) ink Emulsion ink for stencil printing, which has excellent start-up property when left in a drum for a long time, and (5) is environmentally friendly, has not been obtained yet, and its prompt provision is desired. is there.

Japanese Patent No. 2926455 Japanese Patent No. 3008724 JP-A-9-31384

  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 has (1) no stain due to rollers during double-sided printing, (2) excellent persistence (choking) against strong force such as eraser, and (3) little oil separation from ink, (4) An object of the present invention is to provide an emulsion ink for stencil printing which is excellent in standing up property when the ink is left in the drum for a long time, and (5) is environmentally friendly.

  As a result of intensive studies by the inventor in order to solve the above problems, the following knowledge has been obtained. That is, it comprises 10 to 90% by mass of an oil phase and 90 to 10% by mass of an aqueous phase, and contains an alkyd resin having an acid value of 15 or less and an iodine value of more than 80 in the oil phase, The emulsion ink for stencil printing containing polyvinyl pyrrolidone in the aqueous phase is (1) no smearing due to rollers during double-sided printing, (2) excellent persistence (choking) against strong force such as eraser, This is the knowledge that (3) oil separation from ink is small, and (4) emulsion ink for stencil printing is obtained which has an excellent start-up property when the ink is left in the drum for a long time.

The present invention is based on the above knowledge of the present inventor, and means for solving the above problems are as follows. That is,
<1> comprising 10 to 90% by mass of an oil phase and 90 to 10% by mass of an aqueous phase, and containing an alkyd resin having an acid value of 15 or less and an iodine value of more than 80 in the oil phase. The emulsion ink for stencil printing contains polyvinyl pyrrolidone in the aqueous phase. In the emulsion ink for stencil printing of the present invention described in <1>, the oil phase contains an alkyd resin having an acid value of 15 or less and an iodine value of more than 80. A high iodine value means that the molecular structure has many double bonds. When an alkyd resin with a high iodine value is used, the oxygen molecules in the air and the double bond portion undergo an oxidation reaction to polymerize the resin molecules, and the resin component becomes highly viscous and adheres to the paper. It is effective in preventing the occurrence. However, it is known that ink containing an alkyd resin having a high iodine value easily undergoes oxidative polymerization, and therefore, when left in a drum for a long time, it is difficult to eject the ink due to the high viscosity of the resin component. However, even in the above iodine value range, if the alkyd resin has a low acid value (high tendency when there are a large number of hydroxyl groups and carboxyl groups), the emulsion stability of the ink is good and the deterioration of the ink with time is slow. Further, it is possible to provide emulsion ink for stencil printing with less occurrence of stains (roller stains) due to rollers during double-sided printing, and a good rise when the ink is left in the drum for a long period of time. Further, by adding polyvinyl pyrrolidone to the aqueous phase of the emulsion ink, an ink film for forming an image can be strengthened by the film forming performance of the polyvinyl pyrrolidone.
<2> The stencil printing emulsion ink according to <1>, wherein the content of the alkyd resin in the ink is 1 to 7% by mass.
<3> The emulsion ink for stencil printing according to any one of <1> to <2>, wherein the K value in polyvinylpyrrolidone is 15 to 30.
<4> The emulsion ink for stencil printing according to any one of <1> to <3>, wherein the content of polyvinylpyrrolidone in the ink is 0.2 to 1.0% by mass in terms of solid content.
Therefore, in the emulsion ink for stencil printing according to any one of <1> to <4>, a relatively small amount of alkyd resin is responsible for penetration of the pigment into the paper and some drying, and a relatively small amount of polyvinylpyrrolidone. It can bear a weak surface set, does not generate stains due to rollers during double-sided printing, has excellent persistence (choking) against strong forces such as eraser, and the ink has been left in the drum for a long time It is possible to provide an ink that is excellent in time rise.

<5> The emulsion ink for stencil printing according to any one of <1> to <4>, wherein the oil phase contains a colorant. In the emulsion ink for stencil printing according to <5>, a colorant is contained in the oil phase. Although the colorant is effective even when contained in the aqueous phase, the effect of the present invention can be obtained more greatly by adsorbing the alkyd resin in the oil phase to the pigment.
<6> The emulsion ink for stencil printing according to any one of <1> to <5>, wherein the oily phase contains esterified soybean oil and the alkyd resin is a soybean oil fatty acid alkyd resin. In the emulsion ink for stencil printing described in <6>, since vegetable oil is used and long-term leaving property in a drum is not impaired, it is possible to make the ink in consideration of the environment. In stencil printing inks, the alkyd resin is changed to soybean oil fatty acid alkyd, and esterified soybean oil is used, so that the total of soybean oil-derived components exceeds 6%, and the SOY mark is certified by the American Soybean Association. It is advantageous because it is received.
<7> The emulsion ink for stencil printing according to any one of <1> to <6>, wherein the aqueous phase contains at least one of a divalent anion-containing compound and glycerin. In the emulsion ink for stencil printing described in <7>, the yield value as the ink is somewhat low, and there is a tendency for oil separation to be somewhat high, but it contains a divalent anion in the aqueous phase. Thus, since the water phase particle diameter in the ink can be reduced, the yield value can be increased and oil separation can be suppressed. In addition, by containing glycerin in the aqueous phase, the effect of suppressing aging deterioration of the ink due to volatilization of the aqueous phase and the effect of stabilizing the emulsion, while maintaining the effect on roller trace stains, long-term in the drum It is possible to further reduce the quality of the ink when left untreated.

  According to the present invention, various problems in the prior art can be solved, (1) no smearing due to rollers during double-sided printing, (2) excellent persistence (choking) against strong force such as an eraser, and (3) There can be provided an emulsion ink for stencil printing with less oil separation from ink, (4) excellent start-up property when the ink is left in the drum for a long time, and (5) environment-friendly.

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 an alkyd resin in the oil phase, and contains polyvinylpyrrolidone in the aqueous phase. It contains, and further contains other components as necessary.
Here, it is preferable that the alkyd resin has an acid value of 15 or less and an iodine value of more than 80, and the content of the alkyd resin in the ink is 1 to 7% by mass.
Moreover, the aspect whose K value in the said polyvinylpyrrolidone is 15-30, and the content in the ink of this polyvinylpyrrolidone are 0.2-1.0 mass% in solid content concentration are preferable.

In this case, 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.
When 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 when it exceeds 90% by mass, the physical properties are not sufficiently effective. May end up.

<Oil phase>
The oil phase contains an alkyd resin, and further contains other components such as a colorant, a colorant dispersant, an antioxidant, an emulsifier, a vegetable oil, a mineral oil, and an extender if necessary. Become.

-Alkyd resin-
The alkyd resin has an acid value of 15 or less, and more preferably 10 or less. Moreover, an iodine value is more than 80 and 81-110 are more preferable.
If the acid value exceeds 15, the ink may be difficult to eject due to the quality of the ink in the drum of the printing press. Moreover, when the iodine value is 80 or less, stains due to rollers in double-sided printing may easily occur.
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.

The viscosity of the alkyd resin is preferably 20 Pa, 3 Pa · s or more, and more preferably 5 to 20 Pa · s. If the viscosity is less than 3 Pa · s, the ink viscosity ratio may be insufficient, and the ink may not easily penetrate paper.
Here, the viscosity of the alkyd resin can be measured by, for example, a cone plate type rotational viscometer.

  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 triglyceride, and is 50-90 mass% normally.

The alkyd resin is not particularly limited as long as it satisfies the above physical properties, and can be appropriately selected according to the purpose. Usually, the alkyd resin contains an oil, 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.

  1-7 mass% is preferable and, as for the addition amount in the said ink of the said alkyd resin, 3-7 mass% is more preferable. If the amount added is less than 1% by mass, the effect on roller trace stains may be reduced. Even if the amount added exceeds 7% by mass, there is no significant difference in the effect, and the cost may increase. is there.

  In addition to the alkyd resin, the oil phase of the emulsion ink for stencil printing of the present invention may contain other resins as long as the objects and effects of the present invention are not impaired. There is no restriction | limiting in particular as this other resin, According to the objective, it can select suitably according to the objective, for example, rosin; polymerization rosin, hydrogenated rosin, rosin ester, rosin polyester resin, hydrogenated rosin ester Rosin resin such as rosin modified rosin modified alkyd resin, rosin modified maleic resin, rosin modified resin such as rosin modified phenol resin, etc .; maleic resin; phenol resin; petroleum resin; rubber derivative resin such as cyclized rubber; terpene resin; Castor oil and the like can be mentioned, and these may be used alone or in combination of two or more.

-Colorant-
As the colorant, known pigments of various colors, disperse dyes and the like can be used, and among these, pigments are particularly preferable. Examples of the colorant include carbon blacks such as acetylene black, channel black, and furnace black; metal powders such as aluminum powder and bronze powder; inorganic pigments such as petals, yellow lead, ultramarine blue, chromium oxide, and titanium oxide; Azo pigments such as insoluble azo pigments, azo lake pigments, and condensed azo pigments; phthalocyanine pigments such as metal-free phthalocyanine pigments and copper phthalocyanine pigments; anthraquinone pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, dioxane Gin dyes, selenium dyes, perylene dyes, perinone dyes, thioindigo dyes, quinophthalone dyes, condensed polycyclic pigments such as metal complexes; organic pigments such as lakes of acidic or basic dyes; diazo dyes, anthraquinones Oil-soluble dyes such as dyes; fluorescent pigments, etc. Is, it may be used alone or in combination of two or more thereof.

  As the fluorescent pigment, a so-called synthetic resin solid solution obtained by dissolving or dyeing a fluorescent dye that develops various hues after bulk polymerization of a synthetic resin or by pulverizing and refining the obtained colored bulk resin Examples of synthetic resins that carry dyes include melamine resins, urea resins, sulfonamide resins, alkyd resins, and polyvinyl chloride resins.

  When carbon black as the colorant is added to the oil phase, commercially available products can be used as acidic carbon black having a pH of less than 5, for example, MA-100, MA-7, MA-77, MA -11, # 40, # 44 (all manufactured by Mitsubishi Chemical Corporation), Raven 1100, Raven 1080, Raven 1255, Raven 760, Raven 410 (all manufactured by Colombian Carbon).

The average particle diameter of the insoluble colorant is preferably 0.01 to 1.0 μm, and more preferably 0.01 to 0.5 μm.
There is no restriction | limiting in particular in the addition amount in the emulsion ink for stencil printing of the said coloring agent, According to the objective, it can select suitably, Usually, 2-15 mass% is preferable.

-Colorant dispersant-
The colorant dispersant is not particularly limited as long as it does not inhibit the formation of the emulsion, and can be appropriately selected depending on the purpose. For example, the nonionic surfactant for an emulsifier described later, an alkylamine-based polymer Molecular compound, aluminum chelate compound, styrene-maleic anhydride copolymer, partial alkyl ester of polyacrylic acid, polyalkylene polyamine, aliphatic polyvalent carboxylic acid, polyether, ester type anionic surfactant, high molecular weight polycarboxylic acid Long chain amine salts, polyamide compounds, phosphate ester surfactants, alkyl sulfocarboxylates, α-olefin sulfonates, dioctyl sulfosuccinates, polyethylenimine, alkylolamine salts, inhibits ink storage stability Ionic surfactant, amphoteric interface if not Well as sexual agents may be used, these may be used alone or in combination of two or more thereof.
Among these, the aluminum chelate compound is more effective for stains due to the dispersibility of the pigment (the synergistic effect of the adsorption effect of the aluminum chelate compound and the steric hindrance effect of the polyglycerin fatty acid ester compound). And at least one selected from polyglycerin fatty acid ester compounds are preferred.

  There is no restriction | limiting in particular in the addition amount of the said coloring agent dispersing agent, According to the objective, it can select suitably, 40 mass% or less of the total mass of a coloring agent is preferable, and 2-35 mass% is more preferable.

-Antioxidant-
The antioxidant can prevent oxidation of the alkyd resin and the like, can prevent deterioration of the ink when left in the drum for a long time, and can be added to at least one of the oil phase and the water phase. There is no restriction | limiting in particular as this antioxidant, Although it can select and use suitably from well-known things, For example, nordihydroguaiaretic acid (NDGA), a guaiac fat, a citrate ester, extraction tocopherol, tocopherol , Butylhydroxytoluene, gallic acid, dibutylhydroxytoluene, propyl gallate, butylhydroxyanisole, sulfites, thiosulfate, ascorbic acid, ascorbate, ascorbic acid derivatives, etc., which are used alone Alternatively, two or more kinds may be used in combination.
There is no restriction | limiting in particular in the addition amount of the said antioxidant, According to the objective, it can select suitably, 2 mass% or less is preferable with respect to the total amount of ink, and 0.1-1.0 mass% is more preferable.

  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. Examples of the nonionic surfactant include sorbitan fatty acid ester and glycerin. Fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, pentaerythritol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, Polyoxyethylene phytosterol ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, Reoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene lanolin derivatives, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, polyoxyethylene alkylphenyl formaldehyde condensates, etc. You may use, and may use 2 or more types together.

  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.

The vegetable oil is not particularly limited and can be appropriately selected from known ones according to the purpose.For example, 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, bonito oil, palm kernel oil, tung oil, camelia oil, grape seed oil, sweet almond oil, pistachio nut oil, jojoba oil, macadamia nut oil, Meadow home oil and the like can be mentioned, and these may be used alone or in combination of two or more.
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. As the esterified vegetable oil, for example, esterified soybean oil is particularly preferable.
By using soybean oil fatty acid alkyd resin whose fat is soybean oil as the alkyd resin and using esterified soybean oil, the total of soybean oil-derived components exceeds 6%. Certification can be obtained, which is also advantageous in terms of safety.

  The amount of vegetable oil added to the emulsion ink for stencil printing is preferably 1 to 35% by mass, and more preferably 5 to 25% by mass.

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.
As the naphthenic oil, the carbon content (CN) of the naphthene component by ring analysis is 30% by mass or more, the carbon content (CA) of the aromatic component is 20% by mass or less, and the paraffin component Those having a carbon content (CP) of 55% by mass or less are 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; Idemitsu Kosan Co., Ltd. Diana Process Oil, Diana Fresia Series; Nippon San Oil Co., Ltd. Sansen Oil Series.
Commercially available products can be used as the petroleum-based solvent, and examples include Isopar series and Exol manufactured by Exxon Chemical; AF Solvent Series 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 preferably 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, 1-35 mass% is preferable and 5-25 mass% is more preferable.

  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.

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 polyvinylpyrrolidone, other water-soluble polymer compound, water, and if necessary, water evaporation inhibitor or antifreeze agent, electrolyte, O / W resin emulsion, antiseptic / antifungal agent, pH adjuster It contains other components such as.

-Polyvinylpyrrolidone-
There is no restriction | limiting in particular as said polyvinylpyrrolidone (PVP), It can select suitably from well-known things, A commercial item may be sufficient and what was synthesize | combined suitably may be sufficient. These may be used individually by 1 type and may use 2 or more types together.
As said polyvinylpyrrolidone (PVP), what is represented by following Structural formula (1) can be used suitably, for example.

ただし、前記構造式（１）中、ｎは重合度を表す。

However, in said structural formula (1), n represents a polymerization degree.

  The polyvinyl pyrrolidone preferably has a K value of 15-30. Here, the K value means a numerical value serving as a standard for the average molecular weight, the degree of polymerization, and the intrinsic viscosity of polyvinylpyrrolidone. When the K value exceeds 30, the viscosity of the aqueous phase to which polyvinyl pyrrolidone is added becomes too high, and the ink viscosity becomes high, which inhibits the suction of ink from the ink pack and the penetration into the paper during printing. There is.

ただし、前記数式１中、ｃは、ｇ／１００ｍｌ溶液における濃度を表す。ηｒｅｌは、溶媒と比較した溶液の粘度を表す。 The K value can be derived from the measured value of the polyvinyl pyrrolidone viscosity, and can be calculated based on the Fikenscher formula of the following formula 1.
<Formula 1>

However, in the said Numerical formula 1, c represents the density | concentration in a g / 100ml solution. ηrel represents the viscosity of the solution compared to the solvent.

  The content of the polyvinyl pyrrolidone in the emulsion ink for stencil printing is preferably 0.2 to 1.0% by mass in terms of solid content. When the content is less than 0.2% by mass, the effect on roller trace stains may be insufficient. Even if the content exceeds 1.0% by mass, the cost increases on the contrary. Clogging may occur when left unattended.

  In addition to the polyvinyl pyrrolidone, other water-soluble polymer compounds can be added to the aqueous phase as necessary. There is no restriction | limiting in particular as this other water-soluble high molecular compound, According to the objective, it can select suitably, For example, a natural high molecular compound, a semi-synthetic high molecular compound, a synthetic high molecular compound etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

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 semi-synthetic 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 acrylic acid resin derivatives such as polyacrylic acid, sodium polyacrylate, and triethanolamine polyacrylate; synthetic polymer compounds such as polyvinyl alcohol, polyacrylamide, polyethylene oxide, and polyvinyl methyl ether. Etc.

  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.

The water evaporation inhibitor or antifreeze agent is not particularly limited and may be appropriately selected from known ones. Examples thereof include lower saturated monohydric alcohols, glycols and polyhydric alcohols. . These may be used individually by 1 type and may use 2 or more types together.
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, the effect of suppressing the deterioration of the ink with time due to volatilization of the aqueous phase and the effect of stabilizing the emulsion, while maintaining the effect of the alkyd resin against the stains of the roller, the ink of the ink when left in the drum for a long time is maintained. Glycerin is particularly preferable in that the alteration can be reduced.
The addition amount of the water evaporation inhibitor or antifreeze agent is not particularly limited and may be appropriately selected depending on the purpose. It is preferably 15% by mass or less based on the total mass of water in the ink. The mass% is more preferable.

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.
There is no restriction | limiting in particular in the addition amount of the said electrolyte, According to the objective, it can select suitably, 0.1-2 mass% of a water phase is preferable, and 0.5-1.5 mass% is more preferable.

There is no restriction | limiting in particular as said oil-in-water resin emulsion, Although it can select suitably from well-known things and can use, a synthetic polymer compound or a natural polymer compound may be sufficient. 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.

The antiseptic / antifungal agent 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 / antifungal agent is not particularly limited and may be appropriately selected from known ones. Examples include salicylic acid, phenols, methyl p-oxybenzoate, ethyl p-oxybenzoate, and the like. Aromatic hydroxy compounds or chlorinated compounds thereof, sorbic acid, dehydroacetic acid and the like, and these may be used alone or in combination of two or more.
The addition amount of the antiseptic / antifungal agent is not particularly limited and may be appropriately selected depending on the purpose. It is preferably 3% by mass or less based on the total mass of water contained in the ink, More preferably, 2% by mass.

  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.

  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, additives such as an alkyd resin, a colorant, an emulsifier, and other components added as necessary were well dispersed with a three-roll mill to prepare an oil phase by a conventional method. What is necessary is just to gradually add and emulsify an aqueous solution to which polyvinylpyrrolidone is added and other components such as an antiseptic / antifungal agent are added as necessary.

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 .
As described above, the emulsion ink for stencil printing according to the present invention has no occurrence of roller trace stains during double-sided printing, excellent choking, little oil separation from the ink, and when the ink is left in the drum for a long time. It is excellent in start-up property and is suitably used for stencil printing by a rotary stencil printing machine.

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

Example 1
-Preparation of emulsion ink for stencil printing-
Spindle oil as mineral oil (Cosmo Oil Co., Ltd.) 9.0% by mass, Nisseki AF Solvent No. 4 (Shin Nippon Oil Co., Ltd.) 10.0% by mass as mineral oil, and sorbitan emulsifier 3.0 An oil phase was prepared by adding mass% and mixing, and mixing 2.0 mass% of the alkyd resin shown in Table 1 with a stirrer.
On the other hand, 4.0% by mass of phthalocyanine blue (manufactured by Toyo Ink Manufacturing Co., Ltd.), 0.8% by mass of polyvinylpyrrolidone (manufactured by BASF, trade name Luvitec K30, K value = 30), and 69.2% by mass of tap water. The aqueous phase was prepared by mixing with a bead mill.
Next, the water phase was gradually added to the oil phase and emulsified with a disper mixer to prepare an emulsion ink for stencil printing.

(Example 2)
-Preparation of emulsion ink for stencil printing-
Three phthalocyanine blues (manufactured by Toyo Ink Manufacturing Co., Ltd.), 4.0% by mass, spindle oil as mineral oil (manufactured by Cosmo Oil Co., Ltd.), 9.0% by mass, and 2.0% by mass of the alkyd resin shown in Table 1 A pigment dispersion was prepared by kneading with a roll. To this pigment dispersion, 12.0% by mass of Nisseki AF Solvent No. 4 (manufactured by Shin Nippon Oil Co., Ltd.) as a mineral oil and 3.0% by mass of a sorbitan emulsifier were added and mixed to prepare an oil phase. .
Meanwhile, an aqueous phase was prepared by mixing 0.8% by mass of polyvinylpyrrolidone (manufactured by BASF, trade name Luvitec K30, K value = 30) and 69.2% by mass of tap water.
Next, the water phase was gradually added to the oil phase and emulsified with a disper mixer to prepare an emulsion ink for stencil printing.

(Example 3)
-Preparation of emulsion ink for stencil printing-
In Example 2, an emulsion ink for stencil printing was prepared in the same manner as in Example 2 except that 0.5% by mass of magnesium sulfate was added to the aqueous phase and the amount of tap water added was 68.7% by mass. did.

Example 4
-Preparation of emulsion ink for stencil printing-
In Example 2, an emulsion ink for stencil printing was prepared in the same manner as in Example 2 except that 5.0% by mass of glycerin was added to the aqueous phase and the amount of tap water added was 64.2% by mass. .

(Example 5)
-Preparation of emulsion ink for stencil printing-
In Example 2, 4.0% by mass of soybean methyl ester was added to the oil phase, the amount of spindle oil added as mineral oil was 6.0% by mass, and Nisseki AF Solvent No. 4 (manufactured by Nippon Oil Corporation). The emulsion ink for stencil printing was prepared in the same manner as in Example 2 except that the addition amount of 1) was 11.0% by mass.

(Comparative Example 1)
-Preparation of emulsion ink for stencil printing-
In Example 1, the alkyd resin was not added to the oil phase, the amount of spindle oil added as mineral oil was 12.0% by mass, and the amount of tap water added in the aqueous phase was 68.2% by mass. In the same manner as in Example 1, an emulsion ink for stencil printing was prepared.

(Comparative Example 2)
-Preparation of emulsion ink for stencil printing-
In Example 2, an emulsion ink for stencil printing was prepared in the same manner as in Example 2 except that polyvinylpyrrolidone was not added to the aqueous phase and the amount of tap water added was 70.0% by mass.

(Comparative Example 3)
-Preparation of emulsion ink for stencil printing-
In Example 2, the addition amount of the alkyd resin in the oil phase was 10.0% by mass, the addition amount of the spindle oil as the mineral oil was 12.0% by mass, and polyvinyl pyrrolidone was not added to the water phase. An emulsion ink for stencil printing was prepared in the same manner as in Example 2 except that the amount added was 68.0% by mass.

(Comparative Example 4)
-Preparation of emulsion ink for stencil printing-
In Example 1, no alkyd resin was added to the oil phase, the amount of spindle oil added as mineral oil was 12.0% by mass, the amount of polyvinylpyrrolidone added in the aqueous phase was 5.0% by mass, and tap water An emulsion ink for stencil printing was prepared in the same manner as in Example 1 except that the amount added was 64.0% by mass.

  Next, various performances of the obtained emulsion inks for stencil printing of Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated as follows. The results are shown in Tables 1 and 2.

<Evaluation 1: Roll trace stain>
After each ink was sufficiently dispersed in the drum of a stencil printing machine (Preport N-500, manufactured by Tohoku Ricoh Co., Ltd.), solid image printing was performed. After being left for 1 hour after printing, the back side of the image was printed again with a white paper plate making, and the degree of stains on the 100th image was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
◎: No roller trace stains occurred. ○: No roller trace stains occurred. △: Some roller trace stains occurred. ×: Many roller trace stains occurred.

<Evaluation 2: Choking residue>
After each ink was sufficiently dispersed in the drum of a stencil printing machine (Preport N-500, manufactured by Tohoku Ricoh Co., Ltd.), solid image printing was performed. The degree of residual density after the solid image part obtained was rubbed ten times with an eraser was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
A: Almost all images remain (residual density is high).
○: An image remains.
Δ: Image remains but slightly low ×: Image hardly remains (residual density is low).

<Evaluation 2: Centrifugal oil separation amount>
About each ink, 7000G was added for 3 hours with the centrifuge, the quantity of the isolate | separated oil was measured, and the following reference | standard evaluated.
〔Evaluation criteria〕
A: There is almost no separated oil.
○: Slightly separated oil.
Δ: There is a little more separated oil.
X: There are many separated oils.

<Evaluation 4: Standing-up property after being left in the drum for a long time>
After each ink was sufficiently distributed in the printing drum of a stencil printing machine (Tohoku Ricoh Co., Ltd., Preport N-500), the printing drum was left in an oven at 50 ° C. for 2 weeks, and then printing was performed again. And visually observed whether the image appeared on the entire surface, and evaluated according to the following criteria.
〔Evaluation criteria〕
A: The image appears on the entire surface (image restoration is fast).
○: The image is almost on the entire surface.
(Triangle | delta): There exists a part from which the image does not appear partially.
X: Many portions where no image appears are observed (there is a clogged portion that does not completely return).

なお、表１及び表２に示すアルキド樹脂の酸価は、ＪＩＳ Ｋ００７０により測定した。また、アルキド樹脂のヨウ素価は、ＪＩＳ Ｋ００７０により測定した。

The acid values of the alkyd resins shown in Tables 1 and 2 were measured according to JIS K0070. The iodine value of the alkyd resin was measured according to JIS K0070.

From the results of Tables 1 and 2, the emulsion inks for stencil printing in Examples 1 to 5 are (1) no smear due to rollers during double-sided printing, compared to the inks in Comparative Examples 1 to 4. (2 ) Excellent persistence (choking) against strong force such as eraser, (3) Less oil separation from ink, (4) Excellent rise when ink is left in the drum for a long time, and (5) It is recognized that the environment is considered.
That is, it is clear from the comparison between Examples 1 and 2 and Comparative Examples 1 and 2 that there is no stain due to rollers during double-sided printing. Moreover, it is understood from comparing Example 1 with Comparative Example 1 and Comparative Example 4 that the residual property (choking property) against a strong force such as an eraser is excellent. As in Examples 2 to 5, the oil phase It can be seen that the effect is further increased by containing a colorant. Also, it is clear that Example 3 is very superior to Example 1 that oil separation from ink is small. In addition, it can be seen that the ink has excellent start-up property when left in the drum for a long time by comparing Example 1, Comparative Example 3 and Comparative Example 4, and in Example 4, the effect is even greater. it is obvious.
The environmental consideration is clearly recognized from the formulation of Example 5 because the vegetable oil component increases and the mineral oil component decreases.

The emulsion ink for stencil printing of the present invention has no occurrence of roller trace stains when printing on both sides, is excellent in choking properties, has little oil separation from the ink, and has excellent start-up properties when the ink is left in the drum for a long period of time. Moreover, it is excellent in environmental properties, and is suitably used for stencil printing by a rotary stencil printing machine, particularly double-sided printing.

Claims (7)

  Comprising 10 to 90% by mass of an oil phase and 90 to 10% by mass of an aqueous phase, wherein the oil phase contains an alkyd resin having an acid value of 15 or less and an iodine value of more than 80; Emulsion ink for stencil printing characterized by containing polyvinylpyrrolidone in the phase.   The emulsion ink for stencil printing according to claim 1, wherein the content of the alkyd resin in the ink is 1 to 7% by mass.   3. The emulsion ink for stencil printing according to claim 1, wherein the polyvinyl pyrrolidone has a K value of 15 to 30. 4.   The emulsion ink for stencil printing according to any one of claims 1 to 3, wherein the content of polyvinylpyrrolidone in the ink is 0.2 to 1.0 mass% in terms of solid concentration.   The emulsion ink for stencil printing according to any one of claims 1 to 4, comprising a colorant in the oil phase.   The emulsion ink for stencil printing according to any one of claims 1 to 5, wherein the oil phase contains esterified soybean oil and the alkyd resin is a soybean oil fatty acid alkyd resin. The emulsion ink for stencil printing according to any one of claims 1 to 6, wherein the aqueous phase contains at least one of a divalent anion-containing compound and glycerin.