JPH1143633A - Stamp ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stamp ink which can prevent its bleeding by shortening the drying time, can prevent its bias in an impregnated item without adding a thixotropic agent or the like which gives a thixotropy, and also can reduce its cost. SOLUTION: In a stamp ink in which a colorant is dispersed in a vehicle comprising a resin and an oil based solvent, the viscosity of the stamp ink at 2 rpm is regulated in the range of 180-300 ps and the thixotropy index (T.I.) value calculated with the formula is regulated in the range of 1.2-2.0 by controlling the colorant concentration in the range of 3.0-8.0 wt.%, wherein T.I. value=(viscosity of the stamp ink at 2 rpm)/(viscosity of the stamp ink at 20 rpm).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stamp body in which the surface of an impregnated body is covered with a perforated stencil sheet, and the ink impregnated in the impregnated body is perforated through a perforated sheet such as paper. Perform stamp printing by transferring on a print medium,
Regarding the stamp ink used in the so-called stencil printing method, it is possible to prevent the bias of the stamp ink in the impregnated body, particularly without adding a thixotropy-imparting agent that imparts thixotropy to the stamp ink. In addition, the present invention relates to a stamp ink capable of preventing bleeding by shortening the drying time of the stamp ink and reducing the cost.

[0002]

2. Description of the Related Art Conventionally, there are various stamp inks used for stamp printing. For example, a stamp ink which is impregnated on a porous impregnated body made of a sponge or the like or a porous rubber stamp material on a stamp stand is generally used. , Dye, aqueous resin,
It is adjusted from a glycol-based solvent or the like, and its viscosity is low and many of them exhibit fluidity close to Newtonian fluid.

When this type of stamp ink is impregnated into an impregnating body in a stencil printing system and the stamp ink is transferred to a printing medium from the perforations of the stencil sheet, the stencil ink has a low viscosity and is close to a Newtonian fluid. The amount of ink transferred from the perforations in the base paper increases, and bleeding occurs on the printing medium. Further, as time passes, ink drips from the perforations of the stencil sheet and stains the stamp stand and the like. Furthermore, if the stamp stand is set up, the stamp ink impregnated in the impregnating body is deflected downward by gravity, which causes uneven density in the stamp image printed on the print-receiving medium, resulting in a clean stamp image. Cannot be printed. In particular, in summer, when the temperature is high, the viscosity of the stamp ink decreases, and this tendency becomes remarkable.

In order to solve the above-mentioned various problems, for example, JP-A-8-209050 discloses that a vehicle comprising a resin and an oily agent contains a pigment and a thixotropic agent or a plasticizing agent. Stamp inks for stencil printing systems are described.

[0005] If the stamp ink is adjusted to a predetermined viscosity value and a thixotropic index value and used in a stencil printing system, the above-mentioned problems can be solved.

[0006]

By the way, the stamp ink described in the above-mentioned JP-A-8-209050 is provided with a thixotropy by adding a thixo-providing agent. Here, the thixotropy means that when the stamp ink is allowed to stand, it has a gel-like property and has a high viscosity, and when the stamp ink has vibrations and the like, it has a sol-like property and has a low viscosity. Means nature.

On the other hand, the stamp ink has a property of penetrating into the inside of a printing medium and being fixed, but at the time of stamp printing, the stamp ink impregnated in the impregnating body is printed from the perforations of the stencil sheet. When the printing medium is allowed to stand after being transferred to the medium, the stamp ink has a gel-like property based on the thixotropy of the thixotropy-imparting agent, and the viscosity increases. When the viscosity of the stamp ink is increased as described above, the permeation speed into the printing medium decreases, and as a result, the drying time of the ink increases.

As the thixotropic agent, for example, compounds such as aluminum stearate, aluminum octylate, and aluminum oleate are used. However, such compounds are expensive, and therefore, the cost of stamp ink increases. There is also a problem that.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to prevent the bias in the impregnated body without adding a thixotropy-imparting agent or the like that imparts thixotropy. It is another object of the present invention to provide a stamp ink capable of preventing bleeding by shortening a drying time and reducing costs.

[0010]

According to a first aspect of the present invention, there is provided a stamp ink comprising a vehicle comprising a resin and an oily solvent, wherein the colorant has a concentration of 3%. By adjusting the value to 0.0% by weight to 8.0% by weight, the thixotropy index (TI) value calculated based on the following equation is set to 1.2 to 1.2% by weight.
The range is 2.0.

[0011] In the stamp ink according to claim 1, 3.0% by weight to 10% by weight based on a vehicle comprising a resin and an oily solvent.
The thixotropy index value was adjusted to a range of 1.2 to 2.0 without containing a thixotropic agent by containing a coloring agent in the range of 1. Can be kept high, and the drying time of the stamp ink can be shortened.

The thixotropic index value is
From the fact that it is maintained in the range of 1.2 to 2.0, the thixotropic property required for the stamp ink is sufficiently satisfied, and therefore, the stamp body provided with the impregnated body and the stencil sheet is leaned against the stamp body. Even when the stamp ink is left standing, the stamp ink is not biased downward due to its weight. Furthermore, since it is not necessary to include an expensive thixotropic agent, it is possible to reduce the cost of the stamp ink.

Further, the stamp ink according to claim 2 is
In a stamp ink in which a coloring agent is contained in a vehicle made of a resin and an oily solvent, the coloring agent concentration is set to 3.
By adjusting the amount to 0% by weight to 8.0% by weight, 2 rp
The viscosity value of the stamp ink at m is in the range of 180 to 300 poise. As described above, in the stamp ink according to the second aspect, the colorant concentration is 3.0% by weight or more.
Based on adjusting the viscosity value of the stamp ink at 2 rpm to the range of 180 to 300 poise by adjusting to 8.0% by weight, the stamp ink penetrates into the printing medium as in the case of the first embodiment. It is possible to maintain high permeability, thereby shortening the drying time of the stamp ink, and the thixotropic properties required for the stamp ink are sufficiently satisfied. Even when the stamp body with the stencil sheet is stood upright, the stamp ink is not deviated downward due to its weight, and furthermore, it is not necessary to contain an expensive thixotropic agent, It is possible to reduce the cost of stamp ink.

Here, the stamp ink of claim 2 is 2
While the viscosity value at 0 rpm has a substantially constant value irrespective of the colorant concentration, T.V. I. This is in consideration of the fact that the value depends on the viscosity value of the ink at 2 rpm.

It is desirable that the colorant contained in the stamp ink be selected from inorganic pigments and organic pigments.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a stamp ink according to the present invention will be described in detail based on an embodiment embodying the present invention. First, a stencil printing type stamper using the stamp ink of the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view of the stamper, and FIG. 2 is a sectional view of the stamper.

In FIG. 1 and FIG. 2, the stamper 1 has a grip portion 2, a stamp surface holding portion 3, and a stamp surface portion 4.
Is provided with a pad 5 and a stencil sheet 6 impregnated with stamp ink described later.

Here, the pad 5 may be any of paper, cloth, rubber, resin sponge, etc., but in terms of cost and workability,
Resin sponges, especially urethane foam, are preferred.

The stencil paper 6 is made of a thermoplastic film,
It is composed of a porous support and an adhesive layer for bonding them. The thermoplastic film has a thickness of 1 μm to 4 μm,
It is preferably composed of a 2 μm thermoplastic synthetic resin material (eg, polyethylene terephthalate, polypropylene, vinylidene chloride-vinyl chloride copolymer) film. The porous support may be made of natural fibers, such as Manila hemp,
It is composed of a porous thin paper mainly made of semi-synthetic fibers such as rayon, honey, etc.), synthetic fibers (eg, polyethylene terephthalate, polyvinyl alcohol, polyacrylonitrile, etc.) or rayon. The stencil sheet 6 is adhered to the stamp surface holding section 3 and also in contact with the pad 5. After the stencil sheet 6 is heated and perforated by a thermal head to make a stencil, the stencil sheet 6 is attached to the stamper 1 as shown in FIG. The plate is made while being attached to the stamper 1.

In order to perform stamp printing by the stamper 1, the gripper 2 is held by hand and pressed against a printing medium such as paper. As a result, the pad 5 is compressed, and the stamp ink oozes out from the perforated portion of the stencil sheet 6, and the stamp image is printed.

Next, the stamp ink will be described.
The stamp ink basically includes a vehicle made of a resin and an oily solvent containing a coloring agent. As the resin, for example, rosin, rosin ester, rosin-modified maleic resin and the like are suitable. As the oily solvent, those having low volatility are preferable. For example, hydrocarbon solvents having a boiling point of 300 ° C. or higher, spindle oil, liquid paraffin, motor oil, gear oil, petroleum solvents such as machine oil,
And synthetic oils obtained by polymerization of unsaturated hydrocarbons such as ethylene, propylene and butene. Also,
Animal and vegetable oils such as castor oil, tall oil, soybean oil, olive oil, whale oil can also be used. As a coloring agent,
For example, inorganic pigments such as carbon black, red iron oxide, ocher, ultramarine, navy blue and the like, organic pigments such as insoluble azo, soluble azo, phthalocyanine, quinacridone, carmine and dioxazine, oil-soluble dyes and the like are used. Further, various additives may be appropriately contained as needed. For example, a pigment dispersant, a friction resistance improver, an antioxidant, an anti-setoff agent, and the like may be contained.

Next, the stamp ink will be specifically described based on embodiments.

(Example 1) Motor oil and alkyd resin were charged into a four-necked flask equipped with a stirrer, and stirred at 180 ° C for 30 minutes under a nitrogen stream to dissolve the alkyd resin. Further, motor oil was mixed and dispersed with three rolls. Thereafter, if necessary, motor oil is added to reduce the carbon black concentration to 4.0% by weight (black ink A) and 5.0% by weight.
(Black ink B), 6.5% by weight (black ink C),
Five types of black stamp inks were adjusted so as to be 8.0% by weight (black ink D) and 9.0% by weight (black ink E). The viscosity of each stamp ink at 2 rpm and 20 rpm was measured using a BH type viscometer, and the thixotropy index (TI) value was calculated based on the following equation.

[0024] Next, after each of the black inks A to E was impregnated in urethane foam (pad), stamp printing was performed on paper, and tests were performed on the drying properties of the ink, the bias of the ink, and bleeding. Here, the drying property of the ink was evaluated by measuring the time required for the stamp ink to completely penetrate the paper and reach a dry state. For ink bias,
Put the pad impregnated with stamp ink vertically and
After storage at 1 ° C. for 1 month, or after storage at 45 ° C. and 95% humidity for 2 weeks, a printing durability test (number of printings) was performed to evaluate. Regarding the bleeding, the degree of bleeding was evaluated by looking at the stamp image printed on the paper. The evaluation results for each test were as follows: good: good, slightly bad: bad, bad: bad
Indicated by

The results of tests performed on each of the black inks A to E are shown in the table of FIG. In the table of FIG. I. The value was 1.0, the viscosity value of the ink at 2 rpm was 150 ps (poise), the drying property was good, the bias of the ink was poor, and the bleeding was slightly poor. In the black ink A, the carbon black concentration is relatively low (4.
0% by weight), T.I. I. Since the value was also about 1.0, the ink permeability to the paper was good, and the number of times of imprinting without storage was 1,000 times or more, and the printing was performed without being scrambled. However, as for the bias of the ink, if the stamper 1 is tilted and stored as described above, the ink is biased because the thixotropy is slightly inferior.
Less than 0 times, it became bad.

For the black inks B to D, the concentration of carbon black is considered to be in an appropriate range.
T. I. The values also showed good thixotropy, and the viscosity value of the ink at 2 rpm was in an appropriate range. Therefore, good results were obtained in all of the drying properties, ink bias and bleeding.

Further, the black ink E has a relatively high carbon black concentration (9.0% by weight). I.
The value is high (2.2) and the viscosity value of the ink at 2 rpm is high (330 ps), so that the permeability of the ink to the paper is slightly poor. On the other hand, the unevenness of the ink is high because the thixotropic property is high. Does not occur. However, the density is too high, and the image will be scuffed with less than 1000 stamps without storage. When the stamper 1 is strongly pressed to reduce this rub, bleeding occurs on the contrary.

As described above, in the case of black ink, if the concentration of carbon black is in the range of 5.0 to 8.0% by weight,
T. I. It can be seen that when the viscosity value of the ink at a value of 1.2 to 2.0 and 2 rpm is in an appropriate range of 180 ps to 300 ps, a good stamp ink can be obtained with respect to all of the drying property, ink bias and bleeding. .

Example 2 According to the same method as in Example 1, red quinacridone was used as a coloring agent, and the concentration of quinacridone was 4.0% by weight (red ink A), 5.0% by weight. % (Red ink B), 6.5% by weight
(Red ink C), 8.0% by weight (red ink D),
Five types of red stamp inks were adjusted so as to be 9.0% by weight (red ink E). Further, for each red stamp ink, the T.V. I. Each measurement of the value, the drying property of the ink, the bias of the ink, and the bleeding was performed.

The results of tests performed on each of the red inks A to E are shown in the table of FIG. In the table of FIG. I. The value was 1.0, the viscosity value of the ink at 2 rpm was 150 ps (poise), the drying property was good, the bias of the ink was poor, and the bleeding was slightly poor. In red ink A, the quinacridone concentration was relatively low (4.0% by weight). I. Since the value was also about 1.0, the ink permeability to the paper was good, and the number of times of imprinting without storage was 1,000 times or more, and the printing was performed without being scrambled. However, as for the bias of the ink, when the stamper 1 was tilted and stored as described above, the ink was biased because the thixotropy was slightly inferior.

For red inks B to D, the concentration of quinacridone is considered to be in an appropriate range.
I. The values also showed good thixotropy, and the viscosity value of the ink at 2 rpm was in an appropriate range. Therefore, good results were obtained in all of the drying properties, ink bias and bleeding.

Further, the red ink E has a relatively high quinacridone concentration (9.0% by weight). I. The value is high (2.2) and the viscosity value of the ink at 2 rpm is high (330 ps), so that the permeability of the ink to the paper is slightly poor.
There is no bias because of high thixotropic properties. However,
The density is too high, and it will be scuffed with less than 1,000 stampings without storage. When the stamper 1 is strongly pressed to reduce this rub, bleeding occurs on the contrary.

As described above, in the case of the red ink, if the concentration of quinacridone is in the range of 5.0 to 8.0% by weight, T.V.
I. When the viscosity value of the ink at a value of 1.2 to 2.0 and 2 rpm is in an appropriate range of 180 ps to 300 ps,
It can be seen that a good stamp ink can be obtained with respect to all of the drying property, ink bias and bleeding.

(Example 3) According to the same method as in Example 1, red carmine was used as a coloring agent.
5. Carmine concentration of 5.0% by weight (red ink A);
Five types of red colors are set to 5% by weight (red ink B), 8.0% by weight (red ink C), 10.0% by weight (red ink D), and 11.0% by weight (red ink E). Adjusted stamp ink. Further, for each red stamp ink, T.V. I. Each measurement of the value, the drying property of the ink, the bias of the ink, and the bleeding was performed.

The test results performed for each of the red inks A to E are shown in the table of FIG. In the table of FIG. I. The value was 1.0, the viscosity value of the ink at 2 rpm was 130 ps (poise), the drying property was good, the unevenness of the ink was bad, and the bleeding was slightly bad. In the red ink A, the carmine concentration was relatively low (5.0% by weight). I. Since the value was also about 1.0, the ink permeability to the paper was good, and the number of times of imprinting without storage was 1,000 times or more, and the printing was performed without being scrambled. However, as for the bias of the ink, when the stamper 1 was tilted and stored as described above, the ink was biased because the thixotropy was slightly inferior.

For the red inks B to D, the concentration of carmine is considered to be in an appropriate range. I. The values also showed good thixotropy, and the viscosity value of the ink at 2 rpm was in an appropriate range. Therefore, good results were obtained in all of the drying properties, ink bias and bleeding.

Further, the red ink E has a relatively high carmine concentration (11.0% by weight). I. The value is high (2.3) and the viscosity value of the ink at 2 rpm is high (310 ps), so that the permeability of the ink to the paper is slightly poor. On the other hand, the unevenness of the ink is higher because the thixotropic property is higher. Does not occur. However, the density is too high, and the image will be scuffed with less than 1000 stamps without storage. When the stamper 1 was pressed strongly to reduce the rubbing, bleeding occurred on the contrary.

As described above, in the case of the red ink, if the concentration of carmine is in the range of 6.5 to 10.0% by weight, T.V.
I. When the viscosity of the ink at a value of 1.2 to 2.0 and 2 rpm is in a proper range of 150 ps to 260 ps,
It can be seen that a good stamp ink can be obtained with respect to all of the drying property, ink bias and bleeding.

Example 4 According to the same method as that of Example 1, purple dioxazine was used as a coloring agent, and the concentration of dioxazine was 2.0% by weight (purple ink A), 3.0% by weight. % (Purple ink B), 4.5% by weight
(Purple ink C), 6.0% by weight (purple ink D),
Five kinds of purple stamp inks were adjusted so as to be 7.5% by weight (purple ink E). Further, for each purple stamp ink, T.V. I. Each measurement of the value, the drying property of the ink, the bias of the ink, and the bleeding was performed.

The results of tests performed on each of the purple inks A to E are shown in the table of FIG. In the table of FIG. I. The value was 1.0, the viscosity value of the ink at 2 rpm was 150 ps (poise), the drying property was good, the bias of the ink was poor, and the bleeding was slightly poor. In purple ink A, the dioxazine concentration was relatively low (2.0% by weight). I. Since the value was also about 1.0, the ink permeability to the paper was good, and the number of times of imprinting without storage was 1,000 times or more, and the printing was performed without being scrambled. However, as for the bias of the ink, when the stamper 1 was tilted and stored as described above, the ink was biased because the thixotropy was slightly inferior.

For the purple inks B to D, the concentration of dioxazine is considered to be in an appropriate range.
I. The values also showed good thixotropy, and the viscosity value of the ink at 2 rpm was in an appropriate range. Therefore, good results were obtained in all of the drying properties, ink bias and bleeding.

Further, the purple ink E has a relatively high dioxazine concentration (7.5% by weight). I. The value is high (2.2) and the viscosity value of the ink at 2 rpm is high (330 ps), so that the permeability of the ink to the paper is slightly poor.
There is no bias due to high thixotropic properties. However,
The density is too high, and it will be scuffed with less than 1,000 stampings without storage. When the stamper 1 is strongly pressed to reduce this rub, bleeding occurs on the contrary.

As described above, in the case of purple ink, if the concentration of dioxazine is in the range of 3.0 to 6.0% by weight, T.V.
I. When the viscosity value of the ink at a value of 1.2 to 2.0 and 2 rpm is in an appropriate range of 180 ps to 300 ps,
It can be seen that a good stamp ink can be obtained with respect to all of the drying property, ink bias and bleeding.

[0044]

As described above, in the stamp ink according to the first aspect, the coloring agent is contained in the range of 3.0% by weight to 10% by weight with respect to the vehicle comprising the resin and the oily solvent. Since the thixotropic index value was adjusted in the range of 1.2 to 2.0 without including the thixotropic agent, it was possible to maintain high permeability of the stamp ink penetrating into the printing medium, It is possible to shorten the drying time of the stamp ink.

The thixotropic index value is
From the fact that it is maintained in the range of 1.2 to 2.0, the thixotropic property required for the stamp ink is sufficiently satisfied, and therefore, the stamp body provided with the impregnated body and the stencil sheet is leaned against the stamp body. Even when the stamp ink is left standing, the stamp ink is not biased downward due to its weight. Furthermore, since it is not necessary to include an expensive thixotropic agent, it is possible to reduce the cost of the stamp ink.

Furthermore, in the stamp ink according to the second aspect, the viscosity of the stamp ink at 2 rpm is adjusted to 180% by adjusting the colorant concentration to 3.0% by weight to 8.0% by weight.
Based on the range of ~ 300 poise, it is possible to maintain high permeability of the stamp ink penetrating into the printing medium as in the case of the above-mentioned claim 1, thereby shortening the drying time of the stamp ink. The thixotropy required for the stamp ink is sufficiently satisfied.Therefore, even when the stamp body provided with the impregnated body and the stencil sheet is stood upright, the stamp The ink is not deflected downward due to its weight, and it is not necessary to include an expensive thixotropic agent, so that the cost of the stamp ink can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stamper.

FIG. 2 is a sectional view of a stamper.

FIG. 3 is a table showing test results of dryness, ink bias, and bleeding performed on black stamp inks AE.

FIG. 4 is a table showing test results of drying properties, ink bias, and bleeding performed on red stamp inks A to E;

FIG. 5 is a table showing test results of drying properties, ink bias, and bleeding performed on red stamp inks A to E;

FIG. 6 is a table showing test results of drying properties, ink bias, and bleeding performed on purple stamp inks AE.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stamper 3 Stamp surface holding part 4 Stamp surface part 5 Pad 6 Stencil sheet

Claims (3)

[Claims] 1. A stamp ink comprising a coloring agent in a vehicle comprising a resin and an oily solvent, wherein the coloring agent concentration is adjusted to 3.0% by weight to 8.0% by weight. A stamp ink characterized in that a thixotropy index (TI) value calculated based on the value is in a range of 1.2 to 2.0. 2. A stamp ink in which a colorant is contained in a vehicle comprising a resin and an oily solvent, wherein the colorant concentration is adjusted to 3.0% by weight to 8.0% by weight, whereby the stamp at 2 rpm is obtained. A stamp ink wherein the viscosity value of the ink is in the range of 180 to 300 poise. 3. The stamp ink according to claim 1, wherein the colorant is selected from inorganic pigments and organic pigments.