JP4845457B2 - Emulsion ink for stencil printing - Google Patents

Description

  The present invention relates to a water-in-oil type (W / O type) stencil printing emulsion ink having good dispersibility, excellent water resistance and abrasion resistance, and high emulsion stability over time.

In a printing process using a stencil printing apparatus, predetermined original data is converted into a digital signal, and a thermal element called a thermal head is used to punch a plate called a stencil sheet based on the signal and wind it on a printing drum. The At this time, the printing ink passes through the stencil sheet wound by the pressing means below the printing drum and is transferred to the printing sheet.
However, although the ink transferred onto the printing paper is apparently dried due to penetration into the printing paper and evaporation of moisture into the air, it cannot be completely dried and is not dried on the surface of the printing paper. Ink remains. If there is an excessive amount of undried ink after printing, the reverse side of the printing paper stacked on the printing paper will be stained, so-called set-off, and the image immediately after printing will become dirty when touched by hand, so-called hand-rubbing As a result, water resistance and wear resistance are not good. In particular, hand-rubbing occurs more prominently when moisture such as sweat adhering to the hand is present.

In order to solve these problems, the oil phase contains a water-insoluble solvent having a boiling point of 180 to 270 ° C. of 5% by mass or more based on the total amount of the aqueous phase, and is 3 or more with respect to the colorant 1. Resin-added emulsion ink for stencil printing (see Patent Document 1) and stencil printing emulsion ink using an oil-in-water resin emulsion as an aqueous phase and a hydrophobic resin added have been proposed (see Patent Document 2). ). However, there is a problem that the pigment aggregation is promoted by adding the resin and the dispersibility is poor. Also, when water in the ink evaporates over time, the viscosity decreases and the ink drips from the ink roller gap, or the ink's plastic viscosity increases, causing ink to leak from the trailing edge of the drum during printing. There is a possibility that problems such as the above may occur, and there is a problem that the emulsification stability over time is poor. Therefore, it is the present situation that the solution is strongly desired.

JP-A 61-255967 JP-A-6-220382

  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 provides a water-in-oil type (W / O type) stencil printing emulsion ink having good dispersibility, excellent water resistance and abrasion resistance, and high emulsion stability over time. Objective.

  As a result of intensive studies by the inventor in order to solve the above problems, the following knowledge has been obtained. That is, by containing acetylene diol and a nonionic surfactant having an HLB value of 10 or more in at least one of the oil phase and the water phase, dispersibility, water resistance, abrasion resistance, and emulsion stability over time It is the knowledge that is improved.

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> A nonionic surfactant comprising 10 to 50% by mass of an oil phase and 90 to 50% by mass of an aqueous phase, wherein at least one of the oil phase and the aqueous phase has an acetylenic diol and an HLB value of 10 or more. It is an emulsion ink for stencil printing characterized by containing.
<2> The emulsion ink for stencil printing according to <1>, wherein the nonionic surfactant having an HLB value of 10 or more is polyoxyethylene alkyl ether.
In the emulsion ink for stencil printing according to <1> and <2>, by containing acetylene diol and a nonionic surfactant having an HLB value of 10 or more, dispersibility, water resistance, abrasion resistance, In addition, the emulsion stability over time can be improved.

<3> A colorant is contained in at least one of the oil phase and the water phase, and the total content of acetylenediol and a nonionic surfactant having an HLB value of 10 or more exceeds 0 with respect to the colorant. The emulsion ink for stencil printing according to any one of <1> to <2>, which is 10% by mass or less. In the emulsion ink for stencil printing described in <3>, the emulsion stability can be further improved by setting the total content of acetylene diol and HLB value to 10% by mass or less based on the colorant. it can.
<4> The emulsion ink for stencil printing according to any one of <1> to <3>, wherein the HLB value is 5.5 or less. In the emulsion ink for stencil printing described in <4>, the emulsion stability can be further improved by setting the HLB value to 5.5 or less.
<5> The emulsion ink for stencil printing according to any one of <1> to <4>, wherein the content of acetylene diol is 0.5% by mass or more based on the colorant.
<6> The stencil printing emulsion according to any one of <1> to <5>, wherein the content of the nonionic surfactant having an HLB value of 10 or more is 0.5% by mass or more based on the colorant. Ink. In the emulsion ink for stencil printing according to <5> and <6>, the acetylene diol or the HLB value is such that the content of the nonionic surfactant is 0.5% by mass or more based on the colorant. Further, it is possible to further improve dispersibility and improve water resistance and wear resistance.

  According to the present invention, conventional problems can be solved, dispersibility is good, water resistance and abrasion resistance are excellent, and water-in-oil type (W / O type) stencil printing has high emulsion stability over time. Emulsion ink can be provided.

  The emulsion ink for stencil printing of the present invention comprises an oil phase of 10 to 50% by mass and an aqueous phase of 90 to 50% by mass, and at least one of the oil phase and the aqueous phase has an acetylenic diol and an HLB value of 10 or more. The nonionic surfactant is contained, 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.
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.

<Water phase>
The aqueous phase contains acetylenic diol and a nonionic surfactant having an HLB value of 10 or more, and is a colorant, and further contains a water-soluble polymer compound, water, water evaporation inhibitor or freezing as required. It contains components such as an inhibitor, an antibacterial agent, an electrolyte, an extender pigment, an O / W resin emulsion, and a pH adjuster.

-Acetylene Range All-
Acetylene diol (2,4,7,9-tetramethyl-5-decyne-4,7-diol) has a hydrophobic group made of a hydrocarbon branched from a hydrophilic group consisting of a hydroxyl group and a carbon-carbon triple bond. It is a symmetrical nonionic molecule with a sandwiched structure, and is represented by the following structural formula (1).

Since the acetylene diol has a strong hydrophilic group and a hydrophobic group, it can significantly reduce the surface tension and acts as a water-based wetting penetrant.
Moreover, when the fine bubble in a liquid approaches for the following reasons, it is easy to unite and it has a defoaming effect.
1) Since the hydrophilic group is small, water is not carried into the portion where the foam film is stretched and thinned.
2) Since it is a non-ionic molecule, there is no electrical repulsion between the hydrophilic groups of the surfactant molecules on the inner and outer surfaces of the foam film, and there is little steric hindrance due to the hydrophilic groups, so the foam film becomes thinner. Does not prevent you from cutting.
3) Since it is oriented sideways on the surface of the foam, there are few parts adjacent to the adjacent surfactant and the intermolecular attractive force is small.
Further, since it is a hydrophobic surfactant having an HLB value of 4.0, water resistance and thus wear resistance can be improved, and the pigment and the nonionic surfactant can be blended.
What is the content of acetylene diol? Although there is no restriction | limiting in particular, 0.5 mass% or more is preferable with respect to a coloring agent, 0.5-50 mass% is more preferable, 0.5-1.0 mass% is especially preferable.

-Nonionic surfactant with HLB value-
Since the acetylenic diol is a hydrophobic surfactant, it hardly dissolves in water by itself, and it is necessary to add a nonionic surfactant as a solubilizer.
The HLB value of the nonionic surfactant is 10 or more, preferably 10 to 19, and more preferably 15 to 19. If the HLB is less than 10, solubilization is insufficient, and if the HLB exceeds 19, the stability of the emulsion may be affected.
The nonionic surfactant having an HLB value of 10 or more is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene castor oil / cured castor Examples thereof include oils, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene lanolin, lanolin alcohol, beeswax derivatives, and the like.
Examples of the polyoxyethylene sorbitan fatty acid esters include mono coconut oil fatty acid polyoxyethylene sorbitan (n = 20), polyoxyethylene sorbitan monopalmitate (n = 20), and polyoxyethylene sorbitan monostearate (n = 20). ), Polyoxyethylene sorbitan monooleate (n = 20), polyoxyethylene sorbitan monoisostearate (n = 20), and the like.
Examples of the polyoxyethylene castor oil / hardened castor oil include polyoxyethylene hardened castor oil (n = 40, 50, 60).
Examples of the polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether (n = 21, 25), polyoxyethylene oleyl ether (n = 20, 50), and the like.
Examples of the polyoxyethylene polyoxypropylene alkyl ethers include polyoxyethylene polyoxypropylene cetyl ether (m = 4 / n = 10, m = 4 / n = 20, m = 8 / n = 20), polyoxyethylene And polyoxypropyldecyl tetradecyl ether (m = 6 / n = 20, m = 6 / n = 30).
Examples of the polyoxyethylene alkylphenyl ethers include polyoxyethylene nonylphenyl ether (n = 18, 20), polyoxyethylene octylphenyl ether (n = 30), and the like.
Examples of the polyoxyethylene lanolin, lanolin alcohol, and beeswax derivatives include polyoxyethylene lanolin alcohol (n = 20, 40).
These nonionic surfactants may be used alone or in a combination of two or more. In the examples, in the symbols in parentheses, n represents the degree of polymerization of ethylene oxide, and m represents the degree of polymerization of propylene oxide.
However, nonylphenol, which is a raw material of polyoxyethylene nonylphenyl ether, is presumed to have an endocrine disrupting action against medaka at a concentration that may exist in the environment. Therefore, it is preferable to use a nonionic surfactant that does not use an environmental hormone substance, and more preferable to use polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether. .
The content of the nonionic surfactant having an HLB value of 10 or more is not particularly limited, but is preferably 0.5% by mass or more, more preferably 0.5 to 50% by mass with respect to the colorant, and 0 0.5 to 1.0% by mass is particularly preferable.

  The total content of the acetylenic diol and the nonionic surfactant having an HLB value of 10 or more is not particularly limited, but is preferably more than 0 to 10% by mass or less, more preferably 1 to 10% by mass with respect to the colorant. 1 to 3% by mass is particularly preferable. When the total content exceeds 10% by mass with respect to the colorant, the acetylenic diol and the nonionic surfactant itself form micelles and the like, which is sufficient for the wetting and defoaming action of the pigment. The effect may not be obtained.

-Colorant-
The colorant is not particularly limited and may be appropriately selected depending on the intended purpose.For example, carbon blacks, metal powders, inorganic pigments, azo pigments, phthalocyanine pigments, condensed polycyclic pigments, organic pigments, Examples include oil-soluble dyes and fluorescent pigments.
Examples of the carbon blacks include acetylene black, channel black, and furnace carbon.
Representative carbon blacks include, for example, MA-100, MA-7, MA-70, MA-77, MA-11, # 40, # 44 (manufactured by Mitsubishi Chemical Corporation), Raven1100, Raven1080, Raven1255, Raven760, Raven410 (Columbia Carbon Co., Ltd.), etc. are mentioned.
Examples of the metal powder include aluminum powder and bronze powder.
Examples of the inorganic pigment include petals, yellow lead, ultramarine, chromium oxide, and titanium oxide.
Examples of the azo pigment include insoluble azo pigments, azo lake pigments, and condensed azo pigments.
Examples of the phthalocyanine pigment include metal-free phthalocyanine pigments and copper phthalocyanine pigments.
Examples of the condensed polycyclic pigment include anthraquinone, quinacridone, isoindolinone, isoindoline, dioxazine, selenium, berylene, perinone, thioindigo, quinofullerone, and metal complexes. Can be mentioned.
Examples of the organic pigment include lakes of acidic or basic dyes.
Examples of the oil-soluble dye include diazo dyes and anthraquinone dyes.
As the fluorescent pigment, for example, when polymerizing a synthetic resin or after polymerization, a fluorescent dye that develops various hues is dissolved or dyed, and the obtained colored bulk resin is pulverized and refined. Synthetic resin solid solution types are exemplified, and examples of the synthetic resin carrying a fluorescent dye include melamine resin, urea resin, sulfonamide resin, alkyd resin, and polyvinyl chloride resin.
These colorants may be used alone or in combination of two or more.
The volume average particle diameter of the colorant is preferably from 0.1 to 10 μm, and more preferably from 0.1 to 1.0 μm.
2-15 mass% is preferable and, as for content of the said coloring agent, 4-10 mass% is more preferable.
Two or more colorants may be added to the aqueous phase or the oil phase as long as they do not adversely affect other systems.

-Water-soluble polymer compounds-
The water-soluble polymer compound is not particularly limited as long as it can impart moisture retention and viscosity to the stencil printing emulsion ink, and can be appropriately selected from known ones according to the purpose. Examples thereof include a polymer compound, a semi-synthetic polymer compound, and a synthetic polymer compound.
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 polyvinyl pyrrolidone; acrylic resin derivatives such as polyacrylic acid, sodium polyacrylate, and triethanolamine polyacrylate; synthesis of polyvinyl alcohol, polyacrylamide, polyethylene oxide, polyvinyl methyl ether, and the like. Examples thereof include polymer compounds.
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.

-Water-
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.

-Water evaporation inhibitor or antifreeze agent-
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. 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.
The amount of the water evaporation inhibitor or antifreezing agent added in the aqueous phase is preferably 15% by mass or less, and more preferably 4 to 12% by mass.

-Antibacterial agent-
The antibacterial 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 antibacterial agent is not particularly limited and may be appropriately selected from known ones. For example, aromatics such as salicylic acid, phenols, methyl p-oxybenzoate, ethyl p-oxybenzoate, etc. A hydroxy compound or its chlorine compound, sorbic acid, dehydroacetic acid, etc. are mentioned, These may be used individually by 1 type and may use 2 or more types together.
The addition amount of the antibacterial agent in the aqueous phase is preferably 3% by mass or less, more preferably 0.1 to 1.2% by mass.

-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 addition amount of the electrolyte in the aqueous phase is preferably, for example, 0.1 to 2.0% by mass, and more preferably 0.5 to 1.5% 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.
The extender pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include inorganic fine particles and organic fine particles.
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.

-Oil-in-water (O / W) resin emulsion-
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. The minimum film-forming temperature of the oil-in-water resin emulsion is not particularly limited and can be appropriately selected according to the purpose, and is preferably 40 ° C. or lower.

-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.

<Oil phase>
The oil phase contains an emulsifier, an oil component, an antioxidant, a dispersant, a resin, a gelling agent, and other components as necessary. The colorant is as described above.

-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, and a nonionic surfactant is 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 sorbit 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.
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 2.2-6.0 mass% is more preferable. .
The HLB value of the emulsifier is preferably 5.5 or less, more preferably 3.0 to 4.7, and particularly preferably 3.8 to 4.5.

-Oil component-
There is no restriction | limiting in particular as said oil component, According to the objective, it can select suitably according to the objective, A vegetable oil, mineral oil, synthetic oil, etc. are mentioned. However, the oil component may be used by mixing a plurality of different volatile oils for the purpose of improving ink storage stability. However, the volatile oil may have an adverse effect on the global environment. Therefore, it is preferable not to use as much as possible.
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 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.
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.
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 oil component, According to the objective, it can select suitably, 3-30 mass% is preferable, and 15-25 mass% is more preferable.
In consideration of the ink drying property after printing, it is preferable to use an oil component having an iodine value of 100 or more, generally called a drying oil or a semi-drying oil, to which an antioxidant is added. In consideration of fixing the ink in step 1, an iodine value of 100 or less can be used.
Here, the iodine value of the oil component can be measured by, for example, a commercially available edible fat / oil analyzer.
Examples of the edible fat / oil analyzer include an Oil & Fat analyzer edible fat / oil analyzer (manufactured by Yaki Technotron Co., Ltd.).

-Antioxidant-
The antioxidant is not particularly limited and may be appropriately selected from known ones. Examples thereof include nordihydroguaiaretic acid (NDGA), citrate ester, extracted tocopherol, tocopherol, butylhydroxy Examples include toluene, gallic acid, dibutylhydroxytoluene, propyl gallate, butylhydroxyanisole, sulfites, thiosulfate, ascorbic acid, ascorbate, ascorbic acid derivatives, and the like. Two or more kinds may be used in combination.
The amount of the antioxidant added in the oil phase is, for example, preferably 2% by mass or less, and more preferably 0.1-1% by mass.
When an extremely small amount of antioxidant is added to the vegetable oil content, an appropriate antioxidant effect cannot be expected. On the contrary, a large amount of antioxidant is added to the vegetable oil content at once. If it does, it may act as an oxidation accelerator and will also become disadvantageous also in terms of cost. Therefore, it is preferable to add a synergist to suppress the oxidation of vegetable oil even with a small amount of antioxidant.

--Synergist--
The synergist is not particularly limited and can be appropriately selected from known ones. For example, methionine, ascorbic acid, threonine, leucine, milk protein hydrolyzate, norvaline, ascorbyl palmitate, phenylalanine , Cystine, tryptophan, proline, alanine, glutamic acid, valine, pancreatic protein pepsin digestion solution, asparagine, arginine, barbituric acid, asphenamine, ninhydrin, propanidin, histidine, norleucine, glycerophosphate, casein trypsin hydrolyzate, casein Hydrochloric acid hydrolyzate, etc. may be mentioned, and these may be used alone or in combination of two or more.
The addition amount of the synergist is preferably 0.1 to 1% by mass.

-Dispersant-
The dispersant is preferably added when a colorant is also added to the oil phase.
The dispersant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include alkylamine polymer compounds, aluminum chelate compounds, styrene-maleic anhydride copolymer polymers, polycarboxylic acids. Ester type polymer compound, aliphatic polycarboxylic acid, amine salt of polymer polyester, ester type anionic surfactant, long chain amine salt of high molecular weight polycarboxylic acid, salt of long chain polyaminoamide and polymer acid polyester , Polyamide compounds, phosphate ester surfactants, alkyl sulfocarboxylates, α-olefin sulfonates, dioctyl sulfosuccinates, polyethyleneimine, alkylolamine salts, alkyd resins, etc. Resin etc. are mentioned. In addition, ionic surfactants, amphiphilic surfactants, and the like may be used as long as they do not impair the storage stability of the ink. These dispersing agents may be added singly or in combination of two or more.
The addition amount of the dispersant other than the polymer and resin is preferably 40% by mass or less, more preferably 2 to 35% by mass of the colorant.
The alkyd resin is particularly effective for the dispersion stability of the insoluble colorant when a high molecular weight resin is added, but the amount of resin added when the alkyd resin is used alone or in combination with other dispersants. Is preferably 0.05% by mass or more based on the colorant.

-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. Further, the iodine value is preferably 80 or less, and more preferably 80 to 110. 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.

-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.

  In the emulsion ink for stencil printing of the present invention, wax can be added to the oil phase in order to improve separation of the printing paper and the printing drum at the time of 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 the emulsion ink for stencil printing, and the amount of addition may be the same as that of conventional products.

-HLB value of emulsion ink for stencil printing-
The HLB value of the emulsion ink for stencil printing is not particularly limited, but is preferably 5.5 or less from the viewpoint of improving emulsification stability, suppressing oil separation over time, and stability at high temperatures. 0-5.5 are more preferable, 3.0-4.7 are still more preferable, and 3.8-4.5 are the most preferable. When the HLB value exceeds 5.5, oil separation is likely to occur over time, and stability at high temperatures may be reduced. When the HLB value is less than 3.0, emulsification may be difficult.
Here, the HLB value of the emulsion ink for stencil printing is a weighted average value of acetylene diol added to the aqueous phase, a nonionic surfactant having an HLB value of 10 or more, and each emulsifier added to the oil phase. .
Specifically, each HLB value of the acetylene diol, nonionic surfactant having an HLB value of 10 or more, and each emulsifier is multiplied by the content (% by mass) in the emulsion ink for stencil printing. Is a value obtained by dividing the value by the sum of the contents (mass%) of the above components in the emulsion ink for stencil printing.
For example, acetylene diol is 0.04% by mass with respect to stencil printing emulsion ink, and a nonionic surfactant having an HLB value of 13.5 is 0.04% by mass with respect to stencil printing emulsion ink, with an HLB value. If the emulsifier of No. 4.3 contains 5.8% by mass of the emulsion ink for stencil printing, the HLB value of the emulsion ink for stencil printing should be calculated as “4.36” by the following formula. Can do.
〔formula〕
(4.0 × 0.04 + 13.5 × 0.04 + 4.3 × 5.8) ÷ (0.04 + 0.04 + 5.8)
Further, acetylene diol is 0.04% by mass based on the emulsion ink for stencil printing, and a nonionic surfactant having an HLB value of 18.0 is 0.04% by mass based on the emulsion ink for stencil printing, and HLB. An emulsifier having a value of 4.0 is contained in an amount of 0.5% by mass relative to the emulsion ink for stencil printing, and an emulsifier having an HLB value of 4.3 is contained in the emulsion ink for stencil printing containing 5.8% by mass. In this case, the HLB value of the stencil printing emulsion ink can be obtained as “4.36” by the following formula.
〔formula〕
(4.0 × 0.04 + 18 × 0.04 + 4.0 × 0.5 + 4.3 × 5.8) ÷ (0.04 + 0.04 + 0.5 + 5.8)

-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, an oil phase and an 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, an emulsifier, an oil component, and the like are mixed and stirred with a high-speed dissolver. Thereafter, a dispersion treatment is performed using a bead mill to prepare an oil phase. On the other hand, acetylene diol, a surfactant having an HLB value of 10 or more, a water-soluble polymer, an antifreezing agent, an antibacterial agent, an electrolyte, and the like 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 when the shear rate is 20 sec ⁻¹ .

-Application-
As described above, the emulsion ink for stencil printing of the present invention has good dispersibility, excellent water resistance and abrasion resistance, and high emulsification stability with time. For example, stencil printing by a rotary stencil printing machine. Is preferably used.

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-
First, an emulsifier and an oil component 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 colorant, acetylenic diol, nonionic surfactant, water-soluble polymer, water, antifreezing agent, antibacterial agent, and electrolyte were mixed with a homomixer (specialized machinery company) according to the formulations shown in Tables 1-3. Made by KK HOMOMIXER, and then dispersed by a bead mill (LMZ0.6, manufactured by Ashizawa Finetech Co., Ltd.) 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 stencil emulsion ink of Example 1 was produced.

(Examples 2 to 4 and 11, Reference Examples 5 to 10 and Comparative Examples 1 to 4)
In Example 1, except that it changed into the composition shown in Tables 1-3, it carried out similarly to Example 1, and produced the emulsion ink for stencil printing of each example.

[Evaluation]
Next, the following evaluation was performed about each obtained emulsion ink for stencil printing.
(1) Measurement of dispersion time A bead mill (LMZ0.6, manufactured by Ashizawa Finetech Co., Ltd.) was used, and the time until the volume average particle diameter of the colorant became 10 μm was measured. In addition, the said volume average particle diameter was measured by LA-700 (made by Horiba Ltd.).

(2) Evaluation of water resistance An image is printed with Satelio A400 manufactured by Tohoku Ricoh Co., Ltd., and the image after 30 minutes is rubbed with a cloth wetted with water. It was evaluated with.
○: Image rubbing is hardly seen.
Δ: Some image rubbing is seen.
X: Striking of the image is noticeable.

(3) Evaluation of foam generation level The generation level of foam during pre-dispersion by a homomixer (manufactured by Tokushu Kika Co., Ltd., TK HOMOMIXER) was visually evaluated in the following three stages.
○: Almost no bubbles are observed.
Δ: Some bubbles are observed.
X: Generation | occurrence | production of a bubble is seen notably.

(4) Measurement of centrifugal oil separation amount Ink left for 2 weeks at 60 ° C. after production was centrifuged at 6300 G for 3 hours with a centrifuge (manufactured by Sakuma Seisakusho Co., Ltd., M150-IVD) and then generated. The ratio of the obtained oil to the ink mass was calculated as a percentage as the centrifugal oil separation amount.

(5) Evaluation of high-temperature stability The prepared ink was allowed to stand at 60 ° C. for 45 days, and the state of the ink after being left was visually evaluated in the following three stages.
○: No problem in appearance.
Δ: Slightly separated oil and water.
X: Oil and water are separated.

The results of the above (1) to (5) are shown in Tables 1 to 3. In addition, the unit of each component in Tables 1 to 3 is “mass%”.

In Tables 1 to 3, polyglyceric acid fatty acid ester is hexaglycerin polyricinoleate manufactured by Nikko Chemicals, sorbitan monooleate is SO-10 manufactured by Nikko Chemicals, naphthenic oil is SUNTHEN 380 manufactured by Nippon Sun Oil, and soybean oil fatty acid methyl ester. Vertec Biosolvents Vertecbio Gold # 4, Carbon Black 1 is Columbia Carbon Raven 1080, Carbon Black 2 is Columbia Carbon Raven 760, Acetylenediol is Air Products Surfynol 104, Nonionic Surfactant is Nikko Chemicals Polyoxyethylene alkyl ethers or polyoxyethylene alkyl phenyl ethers manufactured by the company, water-soluble polymer is Luvitec K30 solution manufactured by BASF, The antibacterial agent used was Dell Top 512 manufactured by Nippon Enviro Chemicals, the cryoprotectant used was glycerin manufactured by Nippon Oil & Fats, and the electrolyte used was magnesium sulfate heptahydrate manufactured by Kanto Chemical.
In Tables 1 to 3, the HLB value (calculated value) is the content (mass) of each component in the emulsion ink for stencil printing in the respective HLB values of acetylene diol, nonionic surfactant and each emulsifier. %) Is a value obtained by dividing the value (mass%) of each component in the emulsion ink for stencil printing.

From the results of Tables 1 to 3, the emulsion inks for stencil printing of Examples 1 to 4 and 11 and Reference Examples 5 to 10 containing acetylene diol and a nonionic surfactant having an HLB value of 10 or more were dispersed. It was found that the properties were good, the water resistance and the wear resistance were excellent, and the emulsion stability over time was high. In particular, the total content of acetylenic diol and nonionic surfactant having an HLB value of 10 or more is 10% by mass or less based on the colorant, the HLB value is 5.5 or less, and acetylenic diol and In the emulsion inks for stencil printing of Examples 1 to 4 and 11 in which the content of the nonionic surfactant having an HLB value of 10 or more is 0.5% by mass or more based on the colorant, the dispersion time is short, and the image The generation of rubs and bubbles is hardly observed, the amount of centrifugal oil separation is small, and the high-temperature stability is high, which further improves dispersibility, water resistance, abrasion resistance, and emulsion stability over time. I found out that it was planned. In the stencil printing emulsion ink of Reference Example 8, the total content of acetylenic diols and HLB value of 10 or more non-ionic surfactants, for many and 15% by weight, based on the colorant of Example 10 In the emulsion ink for stencil printing, since the HLB value of the emulsion ink for stencil printing was as large as 5.62, the result was that the amount of centrifugal oil separation was large.

The emulsion ink for stencil printing of the present invention is suitably used for stencil printing by, for example, a rotary stencil printing machine because it has good dispersibility, excellent water resistance and abrasion resistance, and high emulsion stability over time.

Claims (6)

Oil phase 10-50% by weight and comprises an aqueous phase from 90 to 50 wt%, to at least one of the oil phase and the aqueous phase, acetylenic diols, HLB value of 10 or more nonionic surfactants and coloring containing agent, wherein is the content of acetylene diol 0.5% by mass or more with respect to the colorant, 0.5% by mass or more relative to the nonionic surfactant content of the coloring agent An emulsion ink for stencil printing having an HLB value of 3.0 to 4.7 .   The emulsion ink for stencil printing according to claim 1, wherein the nonionic surfactant having an HLB value of 10 or more is polyoxyethylene alkyl ether. The total content of A isethionate diol and an HLB value of 10 or more non-ionic surfactants, stencil according to claim 1 which is 1 wt% to 10 wt% of 2 with respect to wear color agent Emulsion ink for printing. The emulsion ink for stencil printing according to any one of claims 1 to 3, having an HLB value of 3.8 to 4.5 . The emulsion ink for stencil printing according to any one of claims 1 to 4, wherein the content of acetylene diol is 0.5% by mass to 1.0% by mass with respect to the colorant. The emulsion ink for stencil printing according to any one of claims 1 to 5, wherein the content of the nonionic surfactant having an HLB value of 10 or more is 0.5% by mass to 1.0% by mass with respect to the colorant. .