JP3254652B2 - 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 has excellent fixability to paper and is free from hand stains.

[0002]

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

Heretofore, solid resins and the like have been added to emulsion inks in order to ensure stability and fixability. For example, by adding three or more resins to Pigment 1 and increasing the oil phase viscosity, the stability and fixability of the ink have been ensured. Also, sorbitan sesquioleate, sorbitan monooleate, and the like have been favorably used as surfactants (Japanese Patent Publication No. 5-62628). But,
Since the drying system for these inks is basically only permeation drying, sufficient fixability cannot be obtained even with a system using a high-concentration resin, and the fixability is improved by improving the ink permeability to paper. However, there is a problem that even if the height is increased, there is no effect on hand stains.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an emulsion ink for stencil printing which eliminates the above-mentioned disadvantages of the prior art and has excellent fixability and is free from hand stains in a rotary stencil printing machine. It is in.

[0005]

According to the present invention, a water-in-oil emulsion composed of about 10 to 90% by weight of an oil phase and about 90 to 10% by weight of an aqueous phase has a boiling point of 350 ° C. or higher in the oil phase. Wherein the content of the water-insoluble liquid is 50% by weight or less based on the total amount of the oil phase component, and a resin is contained in the oil phase.

The present inventors have conducted intensive studies to achieve the above object, and as a result, determined that the content of the water-insoluble liquid having a boiling point of 350 ° C. or higher in the oil phase of the water-in-oil emulsion was reduced to the total amount of the oil phase component. In contrast, it has been found that when the content is 50% by weight or less and a resin is contained in the oil phase, excellent effects on fixability and hand stains are obtained, and the present invention has been achieved. The reason why the emulsion ink of the present invention exhibits such an excellent effect is that by restricting the content of a water-insoluble liquid having a boiling point of 350 ° C. or higher, the evaporation component in the ink after printing is evaporated, and the resin is evaporated. Is sufficiently dried, and the pigment is fixed to the paper by the dried resin, so that it is presumed that the fixing property and the hand stain prevention property are improved.

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

As described above, the emulsion ink of the present invention has excellent fixability and is free from hand stains.
In the oil phase, the content of the water-insoluble liquid having a boiling point of 350 ° C. or more is 50% by weight or less based on the total amount of the oil phase components,
Further, it is characterized by containing a resin. In particular, in the present invention, the oil phase and the aqueous phase are 50 to 80% by weight of the oil phase and 50% by weight of the aqueous phase.
Desirably, it is comprised between 20% and 20% by weight. This is presumably because the effect of the resin is easily exhibited by increasing the amount of the oil phase, which is the continuous phase, and the amount of the resin added can be increased. The amount of the resin used here is desirably 200% by weight or more based on the total amount of the pigment. This is because a certain amount of resin is required to fix the pigment to the paper. The resin used here preferably has a softening point of 80 to 160 ° C. This is because if the softening point of the resin is too low, printed matter is likely to be sticky, and those having a high softening point tend to have poor solubility, so it is difficult for the resin to have a structure in which the resin is elongated in the ink. This is because the fixing effect is not sufficiently exhibited.

[0009] The water-insoluble liquid component (oil component) in the oil phase used in the present invention has a boiling point of 350 ° C or more and a boiling point of less than 350 ° C. The use amount of those having a temperature of not less than 50 ° C. is limited to 50% by weight or less based on the total amount of the oil phase components. As the water-insoluble liquid having a boiling point of less than 350 ° C., any liquid can be used as long as it has the boiling point range, and a petroleum solvent such as Nisseki Isosol, Nisseki Solvent, Nisseki AF Solvent (Nippon Oil Co., Ltd.) ), Ink Solvent (manufactured by Mitsubishi Petrochemical), Shell Dispazol (manufactured by Shell Chemical), Isopar (manufactured by Exxon Chemical), Pegasol, Sartrex (manufactured by Mobile Oil), and the like.

As the other oil components used in the present invention, conventionally known oil components can be applied, for example, mineral oils such as liquid paraffin, spindle oil, light oil, kerosene, machine oil, lubricating oil; linseed oil, tall Vegetable oils such as oil, corn oil, olive oil, rapeseed oil, castor oil and soybean oil are used. In the present invention, a synthetic oil can also be used.
When using synthetic oils, various compounds are available. Representative synthetic vehicles include polyisobutylenes, hydrogenated polydecenes, trimethylolpropane esters, neopentyl and pentaerythritol esters, di (2-ethylhexyl) sebacate, di (2-ethylhexyl) adipate, dibutyl phthalate, Fluorocarbons, silicon esters, silanes, esters of phosphorus-containing acids, liquid urea, ferrocene derivatives, hydrogenated synthetic oils, linear polyphenyls, siloxanes and silicones (polysiloxanes), butyl-substituted bis Examples thereof include alkyl-substituted diphenyl ethers represented by (p-phenoxyphenyl) ethers and phenoxyphenyl ethers.

The emulsifier used in the present invention is preferably a nonionic surfactant, for example, higher sorbitan fatty acid ester, higher polyoxyethylene sorbitan fatty acid ester, fatty acid monoglyceride, fatty acid diglyceride and higher alcohol, alkylphenol, fatty acid and the like. Ethylene oxide adducts of the same type or those having different HLB (hydrophilic-lipophilic balance).
Combine more than one species to prepare highly stable emulsions.

The pigment dispersant used in the present invention includes:
Emulsions that do not inhibit the formation of emulsions are used, for example, alkylamine-based polymer compounds, aluminum chelate-based compounds, styrene / maleic anhydride-based copolymerized polymer compounds, polyalkyl acrylate partial alkyl esters, polyalkylene polyamines, and aliphatic-based compounds. Polyvalent carboxylic acids, amine salts of high molecular weight polyesters, polyethers, ester type anionic surfactants, long chain amine salts of high molecular weight polycarboxylic acids, salts of long chain polyaminoamides and high molecular weight polyesters, polyamide compounds, phosphoric acid Examples include ester surfactants, alkyl sulfocarboxylates, α-olefin sulfonates, dioctyl sulfosuccinates, and the like.

Examples of the pigment used in the present invention include organic and / or inorganic pigments such as furnace carbon black, lamp black, cyanine blue, cyanine green, lake red, titanium oxide, and calcium carbide.

[0014] As the resin used in the present invention, rosin, polymerized rosin, hydrogenated rosin, rosin ester, hydrogenated rosin ester, rosin or rosin-modified resin, such as rosin-modified phenolic resin is used.

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

In the aqueous phase, a water-soluble polymer can be used for moisturizing or thickening. Specific examples of the water-soluble polymer include natural polymers such as starch, mannan, sodium alginate, galactan, tragacanth gum, gum arabic, burlan, dextran, xanthan gum, glue, gelatin, collagen, casein; Semi-synthetic polymers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxymethylstarch, carboxymethylstarch and dialdehyde starch; acrylic resins and acrylic acids such as sodium polyacrylate and triethanolamine polyacrylate Resin derivative, polyvinyl alcohol,
Examples include synthetic polymers such as polyvinylpyrrolidone, polyacrylamide, polyethylene oxide, and polyvinyl methyl ether.

In order to increase the viscosity of the aqueous phase, a thickening accelerator can be used in addition to the water-soluble polymer. For example, as a thickening accelerator used in combination with an acrylic resin, diisopropanolamine, di-2 (ethylhexyl) amine, triethanolamine, triamylamine, b-dimethylaminopropionitrile, dodecylamine, morpholine Examples thereof include low molecular amines such as phosphorus, alkanolamines, and the like, and inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

Further, it is highly preferable that the aqueous phase contains an electrolyte composed of ions located at the upper position of the syneresis sequence in an amount of 0.1% by weight or more of the aqueous phase, because the stability of the emulsion is improved. In this case, as the anion located in the upper part of the syneresis sequence, for example, citric acid, tartaric acid, SO ₄ , CH ₃ CO ₂
And cations such as Li, N
a, K, Mg, Ca and the like, and those containing at least one of these ions are preferable. Specific examples thereof include magnesium sulfate, sodium sulfate, sodium citrate, sodium hydrogen phosphate, sodium borate and the like, and acetic acid can also be used. The aqueous phase may contain an antioxidant, and specific examples thereof include dibutylhydroxytoluene, propyl gallate, and butylhydroxyanisole.

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

[0020]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In addition, all the parts shown below are based on weight.

Example 1 Raw materials having the following formulation were used. (Oil phase component) Colorant Furnace carbon black 4.0 parts Pigment dispersant Aluminum chelate compound 1.0 part (water-insoluble liquid) Emulsifier Sorbitan sesquiolate 3.0 parts (water-insoluble liquid) Oil Spindle oil (boiling point) 3.0 parts (Non-water soluble liquid) Solvent Isopar L (boiling point 190-193 ° C) 20.0 parts 〃 Isopar G (boiling point 159-175 ° C) 9.0 parts Resin Rosin ester (softening point 100 ° C) 20.0 parts (aqueous phase component) Anti-freezing agent Ethylene glycol 3.0 parts Water Deionized water 36.5 parts Electrolyte Magnesium sulfate 0.5 part

The pigment dispersion is prepared by kneading a varnish such as carbon black or rosin ester and a pigment dispersant with a three-roll mill, and adding a surfactant for emulsification, an oil and a solvent to the pigment dispersion. According to the above, a varnish such as rosin ester was further added to obtain an oil phase, and an aqueous phase was added thereto and emulsified to obtain an emulsion ink for stencil printing.

Examples 2 to 12 Emulsion inks for stencil printing were obtained in the same manner as in Example 1 using the formulations shown in Table 1.

Comparative Examples 1 to 4 Emulsion inks for stencil printing were obtained in the same manner as in Example 1 using the formulations shown in Table 2.

[0025]

[Table 1]

[0026]

[Table 2]

(Evaluation) Using the emulsion ink for stencil printing obtained as described above, printing was sufficiently performed with a stencil printing machine (VT3500) manufactured by Ricoh Co., Ltd., and the ink was allowed to pass through the printing machine and then printed. The print density of the printed matter was measured by a reflection type optical densitometer (RD 914 manufactured by Macbeth), and the density after erasing the density measured portion at 10 reciprocations / 10 seconds with a clock meter equipped with an eraser was also measured. The ink fixing rate (fixability) was determined from (density after erasure) / (print density). In addition, hand soiling was evaluated based on the degree of soiling of the cloth when the cloth was rubbed at 10 reciprocations / 10 seconds with a clock meter attached to the cloth. The stickiness was evaluated by leaving the printed matter at 40 ° C. and actually touching the printed matter. These results are summarized in Table 3.

[0028]

[Table 3]

From Tables 1 to 3, the following becomes clear. In the oil phase, the amount of the water-insoluble liquid having a boiling point of 350 ° C. or higher based on the total amount of the oil phase component is set to 50% by weight or less, and the inks of Examples 1 to 12 which contain the resin satisfy the above requirements. When the inks of Comparative Examples 1 to 4 are not compared, the former ink is excellent in fixability and does not cause hand stains.

About 50 to 80% by weight of an oil phase and about 50 of an aqueous phase
Comparing the ink of Example 3 which falls within the range of ~ 20% by weight with the ink of Example 2 which falls within the range of about 10 to 90% by weight of the oil phase and about 90 to 10% by weight of the aqueous phase, the former ink is Since the effect of the resin is easily obtained, the resin is more excellent in fixing property and hand stain prevention property.

The amount of the resin used is 200 relative to the total amount of the pigment.
% Of the ink of Example 1 and the ink of Example 8 outside the same range, and the ink of Example 9 within the same range and the ink of Example 5 outside the same range, respectively. Since the ink can sufficiently fix the pigment to the paper by the resin, the ink is further excellent in fixability and hand stain prevention.

The ink of Example 6 in which the softening point of the resin used is in the range of 80 to 160 ° C., which is out of the same range as the ink of Example 11, and the ink in Example 12 which is in the same range and which is out of the same range as the ink of Example 12. In comparison with the ink of No. 7, the former ink has no stickiness because the resin is sufficiently stretched in the ink, and is excellent in fixability and hand stain prevention.

[0033]

The emulsion ink for stencil printing according to claim 1 is a water-in-oil emulsion composed of about 10 to 90% by weight of an oil phase and about 90 to 10% by weight of an aqueous phase.
Since the content of the water-insoluble liquid having a boiling point of 350 ° C. or higher in the oil phase is 50% by weight or less based on the total amount of the oil phase components, and the resin is contained in the oil phase, the fixing property is improved. Excellent and no stain on hands.

In the stencil printing emulsion ink according to the second aspect, since the oil phase and the aqueous phase are composed of about 50 to 80% by weight of the oil phase and about 50 to 20% by weight of the aqueous phase, the effect of the resin is reduced. It is easy to fix, and it is excellent in fixing property and hand stain prevention property.

In the emulsion ink for stencil printing according to claim 3, the content of the resin is 200% by weight based on the whole pigment.
From the above, the pigment can be sufficiently fixed to the paper by the resin, and further, the fixing property and the hand stain preventing property are excellent.

In the emulsion ink for stencil printing according to the fourth aspect, since the softening point of the resin is 80 to 160 ° C., the resin sufficiently expands in the ink, has no sticky feeling, and further has fixability and hand. It is excellent in stain prevention.

Continuation of front page (56) References JP-A-6-128516 (JP, A) JP-A-7-26186 (JP, A) JP-A-61-255967 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (2)

(57) [Claims] 1. An oil phase of about 50 (excluding 50% by weight or less)
A water-in-oil emulsion composed of 80 % by weight and about 50 to 20 % by weight of an aqueous phase , wherein the oil phase comprises:
The content of the water-insoluble liquid having a boiling point of 350 ° C. or more is 50% by weight or less based on the total amount of the oil phase component, and the resin in the oil phase
Rosin type having a softening point of 80 to 160 ° C or
An emulsion ink for stencil printing, comprising a rosin-modified resin . 2. The content of the resin component is based on the total amount of the pigment.
2. The emulsion ink for stencil printing according to claim 1 , wherein the content is 200% by weight or more .