JP3479793B2 - Emulsion ink for stencil printing - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emulsion ink for stencil printing, and more particularly to an emulsion ink for stencil printing which causes less discoloration due to rubbing (hereinafter referred to as being excellent in dryness to the touch).

[0002]

2. Description of the Related Art As is well known, a stencil printing method uses a stencil printing base paper, and by moving ink from one side of the base paper to the other side through a perforation portion of the base paper, a printing material such as paper is printed. Printing is performed on the surface. In recent years, the automation of a rotary stencil printing machine using a microcomputer or the like has progressed, and the operation has become simpler. Accordingly, the use of stencil printing has increased.

However, the stencil printing is dried only by permeation drying and evaporation drying, and since a reactive resin cannot be added to prevent the ink from solidifying on the machine, stability, In order to secure fixability and dryness to the touch, in JP-A-61-255967, a solid resin or the like is added, and 3 or more resins are added to pigment 1.
By increasing the oil phase viscosity, the stability and fixing property of the ink were secured. In addition, sorbitan sesquioleate, sorbitan monooleate and the like have been favorably used as a surfactant (Japanese Patent Publication No. 5-62628). Further, for the purpose of improving the fixability of the ink, a stencil printing emulsion ink containing a gelling agent of JP-A-5-117564 and a pigment dispersibility as in JP-A-6-128518 are improved. Emulsion inks using expensive dispersants have been proposed. Japanese Patent Application Laid-Open No. 4-183762 and Japanese Patent Application Laid-Open No. 6-220382 disclose a method in which a hydrophobic resin is added to the water phase. In the latter, a large amount of resin is added to the ink in order to improve the fixing property. .

However, in these conventional techniques, the temperature dependency is deteriorated by adding a resin having a high temperature dependency, the cost of the ink is increased by adding an expensive additive, and the water phase is hydrophobic. With the addition of a water-soluble resin, the amount of resin in the water phase is large, so after the ink is transferred to the paper, the permeability of the ink decreases significantly due to the remarkable increase in the viscosity of the ink, and the oil in the oil phase and the complete surfactant There is a problem that a film is not formed and the surface is sticky, and thus a low-cost ink that is excellent in dryness to the touch is desired.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide an emulsion ink for stencil printing which is excellent in dryness to the touch in a rotary stencil printing machine easily and at low cost. To provide.

[0006]

According to the present invention, in a water-in-oil emulsion ink composed of about 10 to 90% by weight of an oil phase and about 90 to 10% by weight of an aqueous phase, an oil-in-water resin in the water phase is provided. The emulsion is a solid content of 0.1 to 1. There is provided a water-in-oil emulsion ink for stencil printing, which is characterized by containing 0 % by weight.

As a result of intensive studies to achieve the above object, the present inventors have found that an oil-in-water resin emulsion is added to the total amount of the ink in the water phase of the water-in-oil emulsion ink.
By adding 0.1 to 1.0 wt% on a solids Te, dry tack excellent stencil printing water-in-oil Emarusho <br/>N'inki was found that obtained at low cost.

The reason is presumed as follows. The oil-in-water resin emulsion is a material usually used for water-based paints and adhesives, and has a film forming ability and an adhesive ability. Replace oil-in-water resin emulsion with water-in-oil emulsion
Oil-in-water type oil, when added to the water phase of water ink to form a film when the water-in-oil emulsion ink is dried.
If there is a lot of resin in the oil emulsion, after the ink adheres to the paper,
Before penetration, the resin in the oil-in-water resin emulsion adheres the pigments to each other, causing the pigments to aggregate, and as a result, the penetration of the ink is hindered. A non-volatile oil and a surfactant are added to prevent the oil from solidifying, but because of this non-volatile oil, the resin in the oil-in-water resin emulsion does not form a dry film, and the film has a sticky feel. Will be formed. This film is weak against strong rubbing by an eraser and may deteriorate the fixing property. In addition, if the solid content is too high, the ink may harden in the machine, which is a drawback. However, since the oil-in-water resin emulsion has adhesive ability, by limiting the addition amount,
It is presumed that the pigments can be adhered to each other without impeding the penetration of the ink into the paper, and as a result, the dryness to the touch is improved. Also, adding a large amount of an oil-in-water resin emulsion will replace water with low cost, which causes a problem of high cost, but a small amount of addition will reduce the effect on cost. Can be expected. The oil-in-water resin emulsion added to the water-in-oil emulsion ink for stencil printing of the present invention has a solid content of 0.1% by weight or more based on the total amount of the ink. It is 0 % by weight or less.

The present invention will be described in more detail below. The emulsion ink for stencil printing of the present invention has an oil phase of about 10 to 9
It is composed of a water-in-oil emulsion composed of 0% by weight and an aqueous phase of about 90 to 10% by weight, and the oil phase is composed of an oil component, a colorant dispersant, a colorant, a resin, an emulsifier, and the like. The aqueous phase is composed of water, electrolyte, antiseptic / antifungal agent, antioxidant, water evaporation inhibitor, water-soluble polymer, oil-in-water resin emulsion (hydrophobic polymer), and the like. Known constituents that do not inhibit the formation of emulsion are used as these constituents.

The colorants (dyes and pigments) used in the present invention include carbon black; azo pigments, phthalocyanine pigments, nitroso pigments, nitro pigments, vat dye pigments, mordant dye pigments, basic dyes. Pigments, acid dyes and natural pigments; oil-soluble dyes such as diazo dyes and anthraquinone dyes. These dyes and pigments may be added alone or in combination of two or more.

As the oil component used in the present invention, conventionally known ones can be applied, for example, mineral oil such as petroleum solvent, liquid paraffin, spindle oil, light oil, kerosene, machine oil and lubricating oil; linseed oil Vegetable oils such as tall oil, corn oil, olive oil, rapeseed oil, castor oil and soybean oil are used. Also, synthetic oils can be used in the present invention. When using synthetic oils, various compounds are available. Typical synthetic vehicles include polyisobutylenes,
Hydrogenated polydecenes, trimethylolpropane esters, neopentyl ester and pentaerythritol ester, di (2-ethylhexyl) sebacate, di (2
-Ethylhexyl) adipate, dibutyl phthalate,
Fluorocarbons, silicon esters, silanes, esters of phosphorus-containing acids, liquid urea, ferrocene derivatives, hydrogenated synthetic oils, chain polyphenyls, siloxanes and silicons (polysiloxanes), butyl-substituted bis Examples thereof include alkyl-substituted diphenyl ethers represented by (p-phenoxyphenyl) ethers and phenoxyphenyl ethers. As the petroleum-based solvent, a mixed solvent such as Expar's Isopar or Nippon Oil Co.'s Nisseki Solvent may be used. These oils may be used alone or in combination of two or more.

The emulsifier used in the present invention is preferably a nonionic surfactant such as sorbitan higher fatty acid ester, polyoxyethylene sorbitan higher fatty acid ester, fatty acid monoglyceride, fatty acid diglyceride and higher alcohol, alkylphenol, fatty acid and the like. The ethylene oxide adducts of the above are listed alone or those having different HLB (hydrophilic / lipophilic balance)
A highly stable emulsion is prepared by combining two or more kinds. The addition amount is 1 to 8% by weight of the ink weight, preferably 2
It may be set to be about 5.5% by weight.

In addition to the above, a resin, a dispersant for a colorant, a gelling agent, an antioxidant and the like can be added to the oil phase within a range that does not interfere with the formation of an emulsion. The colorant and the emulsifier described above are also included in the oil phase. In the aqueous phase, water-soluble polymers, antiseptic / antifungal agents, water evaporation inhibitors, antifreezing agents, pH adjusters, electrolytes, oil-in-water resin emulsions (hydrophobic Molecule) etc. can be added. The resin added to the oil phase is a binder resin that has been conventionally added for the purpose of fixing the colorant and the material to be printed, dispersing the colorant, improving the stability of the ink over time, and the like. Therefore, it is only necessary to add a resin which has been conventionally added, specifically, rosin; rosin-based resin such as polymerized rosin, hydrogenated rosin, lysine ester, hydrogenated rosin ester; rosin-modified resin such as rosin-modified phenolic resin. Phenol resin, petroleum resin, alkyd resin, rubber derivative, polymerized castor oil, etc. may be added singly or in a mixture of two kinds. Further, the addition amount may be 10% by weight or less of the ink weight, preferably 1 to 7% by weight.

As the dispersant for the colorant used in the present invention, those which do not inhibit the formation of emulsion are used.
The above-mentioned nonionic surfactants for emulsifiers can be used. In addition to these, for example, alkylamine-based polymer compounds, aluminum chelate-based compounds, styrene / maleic anhydride-based copolymerized polymer compounds, polycarboxylic acid ester-based polymer compounds, aliphatic polyvalent carboxylic acids, amines of polymer polyesters Salts, ester-type anionic surfactants, long-chain amine salts of high molecular weight polycarboxylic acids, salts of long-chain polyaminoamides and high-molecular acid polyesters, polyamide compounds, phosphate ester-based surfactants, alkylsulfocarboxylates, α -Olefin sulfonates, dioctyl sulfosuccinates, and resins having pigment dispersing ability such as alkyd resins are also included. These dispersants may be added alone or in admixture of two or more, and the addition amount thereof is 40% by weight or less based on the weight of the colorant, preferably 2 to
It may be 35% by weight.

The gelling agent has a role of gelling the resin contained in the oil phase to improve the storage stability, fixing property and fluidity of the ink, and as the gelling agent added to the ink of the present invention, Compounds that coordinate with the resin in the oil phase are preferred.
Examples of such compounds include Li, Na, K, A
l, Ca, Co, Fe, Mn, Mg, Pb, Zn, Zr
Such as an organic acid salt containing a metal, an organic chelate compound, a metal soap oligomer and the like, and specifically, a metal octylate such as aluminum octylate, a metal naphthenate such as manganese naphthenate, a stearin such as zinc stearate. Examples thereof include acid salts and organic chelate compounds such as aluminum diisopropoxide monoethylacetoacetate. One or more of these gelling agents may be added to the oil phase, and the addition amount thereof is 15% by weight or less of the resin in the oil phase,
It is preferably 5 to 10% by weight.

Antioxidants added to the oil phase are dibutylhydroxytoluene, propyl gallate, butylhydroxyanisole and the like, and the addition of these prevents the binder resin and the like in the oil phase from oxidizing, thereby increasing the ink viscosity. The rise is prevented. The addition amount is 2% by weight or less, preferably 0.1 to 1.0% by weight of the oil in the ink. The antioxidants may be used alone or in combination of two or more.

The water-soluble polymer added to the water phase of the emulsion ink is added for the purpose of moisturizing and thickening. Specifically, the following natural or synthetic polymers are added. For example, starch, mannan, sodium alginate,
Natural polymers such as galactan, tragacanth gum, gum arabic, vullan, dextran, xanthan gum, glue, gelatin, collagen, casein; kilvoxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxymethylstarch, carboxymethyl. Semi-synthetic polymers such as starch and dialdehyde starch; acrylic acid resins and sodium polyacrylate, acrylic acid resin derivatives such as polyacrylic acid triethanolamine, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyethylene oxide, polyvinyl methyl ether, etc. And synthetic polymers of These water-soluble polymers may be used alone or as a mixture of two or more kinds.
Up to and including 0.5% by weight, preferably 0.5 to 15% by weight is added.

The antiseptic / antifungal agent added to the aqueous phase is added to prevent the growth of bacteria and mold in the emulsion, and when the emulsion is stored for a long time, the antiseptic / antifungal agent is usually added. . The amount added is 3% by weight or less of water contained in the ink, preferably 0.1 to 1.2% by weight. As antiseptic / antifungal agents, salicylic acid, phenols, methyl p-oxybenzoate,
In addition to aromatic hydroxy compounds such as ethyl p-oxybenzoate and chlorine compounds thereof, sorbic acid, dehydroacetic acid and the like are used, and these may be used alone or in combination of two or more kinds.

The water evaporation inhibitor and the antifreezing agent can be used together, and the chemicals added for these purposes are glycols such as ethylene glycol, diethylene glycol and propylene glycol; methanol, ethanol, isopropanol, butanol, isobutanol, etc. And lower saturated monohydric alcohols; polyhydric alcohols such as glycerin and sorbitol; These chemicals may be added singly or in a combination of two or more, and the addition amount is 15% by weight or less, preferably 4 to 12% by weight based on the weight of water in the ink.

Since the stability of the oil-in-water type resin emulsion added to the aqueous phase may change depending on the pH value, the stability of the oil-in-water type resin emulsion may change depending on the pH value. The pH value may be adjusted as necessary so as not to impair the stability. Oil-in-water resin emulsions include vinyl acetate, acrylic acid ester, methacrylic acid ester, vinyl chloride, ethylene / vinyl acetate copolymer, vinyl acetate /
Examples thereof include acrylic acid ester copolymers, styrene / acrylic acid ester copolymers, vinylidene chloride / acrylic acid ester copolymers, vinyl chloride / vinyl acetate copolymers, urethanes and the like. These oil-in-water resin emulsions may contain a dispersant, a protective colloid, and a surfactant, as long as they do not impair the stability of the water-in-oil emulsion ink, and are synthesized by soap-free emulsion polymerization. You can use what you have done. Particularly preferred is an acrylic acid ester-based resin emulsion, which has excellent emulsifying properties. In addition, the film-forming temperature (MFT) of these resins
Is preferably 40 ° C. or lower. M. F.
In order to reduce T, a glycol-based compound such as ethylene glycol monobutyl ether or an ester-based compound such as a phthalate-based plasticizer can be appropriately used as a film-forming aid. The oil-in-water resin emulsion can be produced by emulsion polymerization or soap-free emulsion polymerization by a solution emulsification method, a melt emulsification method, or the like. Further, as commercially available products, Boncoat 5450 (styrene / acrylic ester copolymer) [Dainippon Ink and Chemicals, Inc.], Bonron S-4
85 (acrylic acid ester) [Mitsui Toatsu Kogyo Co., Ltd.] and the like can be used.

The pH adjusting agent added to the aqueous phase is triethanolamine, sodium acetate, triamylamine and the like. When necessary, these pH adjusting agents are added to keep the pH of the aqueous phase at 6 to 8. You can If the pH of the aqueous phase deviates from the previous range, there is a problem that the effect of the water-soluble polymer for a thickener is impaired when added.

The electrolyte added to the aqueous phase is added to enhance the stability of the emulsion. Therefore, it is preferable to add to the electrolyte an electrolyte composed of ions having a high syneresis sequence, which is effective for improving the stability of the emulsion. Anions with high syneresis are citrate,
Since cations such as tartrate ion, sulfate ion, and acetate ion, which have high syneresis per se, are alkali metal ions and alkaline earth metal ions, the electrolyte added here should be at least anion or cation. Salts in which one of the above ions is included are preferred. Therefore, as the electrolyte added here, magnesium sulfate, sodium sulfate, sodium citrate, sodium hydrogen phosphate, sodium borate, sodium acetate, etc. are preferable, and the addition amount thereof is 0.1 to 2% by weight of the aqueous phase. , Preferably 0.5-
It is 1.5% by weight.

In addition to the above, the water-in-oil emulsion ink for stencil printing of the present invention has an oil phase to improve the separation between the printing paper and the printing drum during printing or to prevent the printing paper from rolling up. Wax can be added to the. Further, triethanolamine, sodium hydroxide or the like can be added to the aqueous phase to further increase the viscosity by adding a water-soluble polymer. Further, by adding a rust preventive agent or an antifoaming agent to the aqueous phase, it is possible to prevent the printing machine from rusting or the ink foaming during printing. Known additives that have been added to stencil printing inks may be added as necessary to these additives, and the amount of addition may be approximately the same as in the case of conventional products.

The emulsion ink of the present invention may be prepared by preparing an oil phase and an aqueous phase liquid in the same manner as in the conventional production of emulsion ink and emulsifying both of them in a known emulsifying machine to obtain an ink. That is, an oil in which additives such as a colorant, an emulsifier, and a resin that is added as necessary are well dispersed is prepared at room temperature, and an antiseptic / antifungal agent, a water-soluble polymer, or the like is added to the oil, if necessary. The prepared aqueous solution may be gradually added to emulsify.

[0025]

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

Example 1 The raw materials of the formulations shown below were used. (Colorant) Carbon black 4.0 parts (Solvent) Spindle oil 21.0 parts (Pigment dispersant) Aluminum chelate 0.3 parts (Emulsifier) sorbitan sesquioleate 4.7 parts (Water) Deionized water 58.0 parts (Anti-freezing agent) Ethylene glycol 10.0 parts (Electrolyte) Magnesium sulfate 1.0 part   Styrene / acrylic ester oil-in-water resin emulsion (solid) 1.0 part

The pigment dispersion is prepared by kneading carbon black, a spindle oil and a pigment dispersant with three rolls, and the pigment dispersion is mixed with an emulsifying surfactant and oil, and if necessary, rosin. An emulsion ink for stencil printing was obtained by adding a varnish such as a modified phenolic resin to obtain an oil phase and adding an aqueous phase containing an oil-in-water resin emulsion to the oil phase and emulsifying the emulsion.

Example 2 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the raw materials having the following formulations were used. (Colorant) Carbon black 4.0 parts (solvent) Spindle oil 8.0 parts Petroleum solvent 7.0 parts (resin) Rosin-modified phenolic resin 6.0 parts (emulsifier) Sorbitan sesquioleate 5.0 parts (water) Ion-exchanged water 58.0 parts (antifreeze agent) Ethylene glycol 10.0 parts (electrolyte) Magnesium sulfate 1.0 part Acrylic ester oil-in-water resin emulsion (solid content) 1.0 part

Reference Example 3 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the following raw materials were used.

Example 4 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the raw materials having the following formulations were used. (Colorant) Carbon black 4.0 parts (Solvent) Spindle oil 21.0 parts (Pigment dispersant) Aluminum chelate 0.3 parts (Emulsifier) Sorbitan sesquioleate 4.7 parts (Water) Ion-exchanged water 58.8 parts (Antifreezing agent) Ethylene glycol 10.0 parts ( Electrolyte) Magnesium sulfate 1.0 part Styrene / acrylic ester oil-in-water resin emulsion (solid content) 0.2 part

Comparative Example 1 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the following raw materials were used. (Colorant) Carbon black 4.0 parts (Solvent) Spindle oil 21.0 parts (Pigment dispersant) Aluminum chelate 0.3 parts (Emulsifier) Sorbitan sesquioleate 4.7 parts (Water) Ion-exchanged water 59.0 parts (Antifreezing agent) Ethylene glycol 10.0 parts ( Electrolyte) Magnesium sulfate 1.0 part

Comparative Example 2 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the raw materials having the following formulations were used. (Colorant) Carbon black 4.0 parts (Solvent) Spindle oil 21.0 parts (Pigment dispersant) Aluminum chelate 0.3 parts (Emulsifier) Sorbitan sesquioleate 4.7 parts (Water) Ion-exchanged water 56.0 parts (Anti-freezing agent) Ethylene glycol 10.0 parts ( Electrolyte) Magnesium sulfate 1.0 part Acrylic ester oil-in-water resin emulsion (solid content) 3.0 parts

Comparative Example 3 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the raw materials having the following formulations were used. (Colorant) Carbon black 4.0 parts (Solvent) Spindle oil 21.0 parts (Pigment dispersant) Aluminum chelate 0.3 parts (Emulsifier) Sorbitan sesquioleate 4.7 parts (Water) Ion-exchanged water 58.95 parts (Antifreezing agent) Ethylene glycol 10.0 parts ( Electrolyte) Magnesium sulfate 1.0 part Acrylic ester oil-in-water resin emulsion (solid content) 0.05 part

Comparative Example 4 An emulsion ink for stencil printing was obtained in the same manner as in Example 1 except that the following raw materials were used. (Colorant) Carbon black 4.0 parts (Solvent) Spindle oil 21.0 parts (Pigment dispersant) Aluminum chelate 0.3 parts (Emulsifier) Sorbitan sesquioleate 4.7 parts (Water) Ion-exchanged water 29.5 parts (Antifreezing agent) Ethylene glycol 10.0 parts ( Electrolyte) Magnesium sulfate 1.0 part Acrylic ester oil-in-water resin emulsion (solid content) 29.5 parts

(Evaluation of Emulsion Ink) Using these inks, a commercial stencil printer (VT350 manufactured by Ricoh Co., Ltd.) was used.
0) was sufficiently printed to spread the ink in the printing machine and then printed. The printing density of the printed matter at this time was measured by a reflection type optical densitometer (RD914 manufactured by Macbeth Co.). The temperature dependence was evaluated by performing the above printing at 10 ° C. and 30 ° C. and measuring the density difference. 0.3 or less is ◎, 0.3
1 to 0.35 were evaluated as ◯, and 0.35 or more were evaluated as x. Further, the fixability of the printed matter, the dryness to the touch, the sticky feeling, and the dryness of the ink were evaluated. The evaluation and measurement methods are as follows. The results are summarized in Table 1.

The area after the fixing print density was measured was also measured with a clock meter equipped with an eraser at 10 reciprocations / 10 seconds, and the density was also measured. From (density after deletion) / (print density) The fixing rate was calculated. A sample having the same level as that of Comparative Example 1 was marked with ◯, and a sample having an obviously poor level was marked with x. The touch-drying printed portion was rubbed with a clock meter equipped with a cloth at 10 reciprocations / 10 seconds, and the soiling condition of the cloth was compared and determined. The one with little stain on the cloth was evaluated as touch-drying property ○, and the one with much stain on cloth was evaluated as touch-free property ×. The sticky printed material was evaluated by touching it with the hand. The state of film formation when the dry ink was allowed to stand in the atmosphere was evaluated, and those that did not form a film were rated as ◯ and those that formed were rated as x.

[0037]

[Table 1]

[0038]

The water-in-oil type emulsion ink for stencil printing according to claim 1 comprises an oil-in-water type resin emulsion in the aqueous phase in a solid content of 0.1 to 1. Since the content is 0 % by weight, it is excellent in dryness to the touch and can be obtained at a relatively low cost.

In the emulsion ink for stencil printing according to the second aspect, since the acrylic acid ester type resin emulsion is used as the oil-in-water type resin emulsion, the effect of improving the emulsifying property is added.

Claims (2)

(57) [Claims] 1. An oil phase of about 10-90% by weight and an aqueous phase of about 90-.
Oil consisting of 10 wt% aqueous emulsion Lee
In the ink tank, an oil-in-water resin emulsion was added to the aqueous phase in a solid content of 0.1 to 1. A water-in-oil emulsion ink for stencil printing, characterized by containing 0 % by weight. Wherein said oil-in-water resin emulsion for stencil printing water-in-oil emulsion ink according to claim 1, wherein the resin emulsion of acrylic ester.