JPH0515089Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention allows printed matter placed in a natural environment to change color depending on the relative humidity of the environment, so that humidity can be determined. Relating to a humidity indicator consisting of a screen print.

[Conventional technology]

There are several types of moisture-sensitive basic dyes, such as cobalt chloride, cobalt bromide, rhodamine, crystal violet, and others, but the color tone produced when the dye itself absorbs moisture varies depending on the dye.

[Problem that the invention attempts to solve]

If you try to use the moisture-sensitive dyes mentioned above as printing inks for multicolor printing (including those using the primary color separation method), the tone and number of colors will not match.
The resulting humidity-sensitive printed matter is unbalanced and has low product value.

In addition, in order for humidity-sensitive printed matter to attract the attention of viewers, it is necessary that the color change quickly in response to changes in the surrounding relative humidity. However, in conventional methods, in order to make the dye into a printable ink, binders, resins, etc. are mixed in addition to pigments and dyes, and as a result, the moisture-sensitive components are excessively diluted. , the range of color change is narrowed,
The degree of color development weakened when the humidity changed, making it impractical.

In view of the above-mentioned problems, the present invention has been developed to easily match the tone and number of colors even when printing in multiple colors, and to achieve good balance.
Moreover, it is an object of the present invention to provide a moisture-sensitive printed matter that exhibits good response to changes in humidity and good color development.

[Means for solving problems]

The present invention consists of a substrate and a printing section formed on the surface of the substrate. It is characterized by comprising a screen-printed part that changes color depending on the relative humidity in the air, and a humidity indicator part that is printed using a paint that does not change the color tone that the screen-printed part exhibits at each relative humidity. The above objectives are achieved by means of a humidity indicator.

[Effect]

The printing ink used for the humidity indicator of the present invention is based on a humidity-sensitive basic dye.The humidity-sensitive basic dye is dissolved in water and absorbed into a water-absorbing powder to obtain an appropriate viscosity as a printing ink. Contains pigments or dyes. Therefore, even when printing in multiple colors, the tone and number of colors can be easily matched, and a well-balanced printed product can be obtained.

As the moisture-sensitive basic dye of the present invention, cobalt chloride, cobalt bromide, rhodamine, crystal violet, etc. can be used.

Water-absorbing powder is a powder that absorbs moisture, and includes natural polymer compounds such as alginate, carrageenan, pectin, chitosan salt, etc., which are described as hydrophilic polymer compounds in JP-A-58-32671, and cations. Semi-synthetic polymer compounds such as starch, carboxymethyl cellulose, carboxymethylated starch, carboxymethylated daa gum, etc., polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid amide, polymaleic acid copolymer, etc., and powders of mixtures thereof. used.

In addition, since the screen-printed portion of the printed matter of the present invention is screen-printed, the printed surface has many fine irregularities, the moisture-sensitive area is extremely large, and it is sensitive to ambient humidity. Contains water-absorbing powder to ensure absorption of ambient humidity. Therefore, the humidity indicator of the present invention changes color quickly and has a wide range of change in response to changes in humidity.

In the present invention, a humidity indicator part is provided together with the screen-printed part, which is printed using an ordinary paint that does not change in humidity, so that the color tones of the screen-printed part exhibits at each relative humidity are printed as humidity indicators. You can easily know the humidity by comparing the parts.

The humidity indicator of this invention uses paper that uses natural pulp as its base, and when printed on such paper, the color change of the moisture-sensitive ink is delayed due to the absorbency of the paper itself. It is preferable to use the material as a base and print on it.

In addition, if the substrate to be printed is stretchable,
Small amounts (eg, about 0.3%) of vinyl acetate can be incorporated into the printing inks used in the present invention to increase their tackiness against stretching. Also, for example about 0.5%
Adhesive strength can be increased by incorporating a water-based adhesive into the printing ink used in the present invention.

Furthermore, if moisture-absorbing and moisture-sensitive components are exposed on the surface of the printed material and there is a risk that they will be washed away by the attached moisture and the moisture-sensing effect will be reduced, approximately 20% moisture-absorbing powder should be mixed into the oil-based resin. , it may be printed solidly as a protective film on the surface of the screen-printed printed matter of the present invention. If you do this, the color change will be slightly (about 20 seconds) compared to the case without a protective film.
However, the moisture-absorbing powder in the protective film absorbs moisture in the surrounding atmosphere and acts on the moisture-sensitive components in the moisture-sensitive printing ink to cause discoloration, resulting in a product that is sufficiently durable for practical use.

〔Example〕

The present invention will be described in detail below based on Examples.

Example 1 By volume, 1 part of cobalt chloride crystals was mixed with 2 parts of water and absorbed into 2 parts of water-absorbing powder to give a suitable viscosity for a printing ink.

After screen printing was performed on the substrate using a 230-mesh screen using the printing ink having the above formulation, the substrate was slowly dried immediately after printing, and finally dried with a hair dryer.

As a result, the same color tone as that obtained by coating and drying an aqueous solution of 1 part of cobalt chloride dissolved in 2 parts of water was obtained. In other words, cobalt chloride is pale pink when it is liquid (humidity 100%), and is pale pink when it is crystalline (humidity 40%).
%), the color is deep purple, and the humidity indicator of the present invention is similarly pale pink when it is humid.
When dry, it took on a dark purple color.

Therefore, it was possible to easily know the humidity by printing a humidity indicator part, which is pale pink for 100% humidity and dark purple for 40% humidity, together with the screen-printed part using ordinary paint that does not change humidity. .

Example 2 2 parts of water-absorbing powder was added to an aqueous solution prepared by mixing 1 part of cobalt chloride crystals with 2 parts of water, and the mixture was stirred for 3 minutes using a stirrer to obtain a suitable viscosity for printing ink. 0.1 part of a yellow aqueous pigment was added to this to obtain a bright yellow ink. The humidity of the ink at this time was 100%. Next, using this ink, we printed on a synthetic paper substrate with a 230-mesh screen solid plate in a room at a temperature of 20°C and humidity of 50% (as measured by a wet and dry bulb hygrometer), and the color tone was the same as that of the ink. was gotten.

When this printed matter (humidity indicator) was left to dry, it reached the same humidity level as the indoor humidity (50% humidity) after about 30 minutes.
%) and exhibited a bright green color.

The next morning, it was raining outside and the hygrometer was reading 65%.
The printout (humidity indicator) created the day before had turned a lemon yellow with a strong bluish tinge.

When I left it indoors, the hygrometer read
At 60%, the print (humidity indicator) turned pale green.

Additionally, when I took the print out outside in the rain (under the eaves), it turned bright yellow after about 10 seconds.
At this time, the hygrometer was reading 70%.

On another day, I left it outside in the sun on a car for an hour, and it turned dark green. The hygrometer read 30%.

Based on the results of Example 2 above, the following printed matter (humidity indicator) was created.

Using the printing ink obtained in Example 2 above, as shown in FIG. 1, screen printing 2 was carried out with a solid plate on the top of synthetic paper 1 as a base.

Next, as shown in Figure 2, on top of the screen printing 2, a desired pattern is formed by mixing about 20% moisture-absorbing powder into an oil-based resin and applying a colored protective film to hide the screen printing 2. Plain cutout 3
Offset printing 4 was carried out so that the plain blank part became a screen printed part 5 whose color changed depending on the relative humidity in the air.

At the bottom of the synthetic paper 1, a humidity indicator part 6 is formed in a rectangular shape by printing the color tone that the screen-printed part 5 exhibits at each relative humidity using an ordinary paint that does not change in humidity. A moisture-sensitive screen print of the present invention was obtained by adding the humidity indicated by the color.

Example 3 2 parts of water-absorbing powder was added to an aqueous solution prepared by mixing 1 part of cobalt chloride crystals with 2 parts of water, and the mixture was stirred for 3 minutes using a stirrer to obtain a suitable viscosity for printing ink. To this, 0.1 part of a pink aqueous pigment was added to obtain a pink ink. A screen print (humidity indicator) made using this ink changed color in response to humidity as follows.

Humidity 70% or more Bright pink Humidity 65% Pink with a slight purple tinge Humidity 60% Strong purple pink Humidity 50% Purple Humidity 30% Dark purple Example 4 Blue pigment in place of the pink aqueous pigment in Example 3 above It was used. A screen print (humidity indicator) made using this ink changed color in response to humidity as follows.

Humidity 70% or more Pale blue Humidity 65% Slightly bright blue Humidity 60% Bright blue Humidity 50% Bright blue Humidity 30% Dark blue Example 5 Compared to Examples 2 to 4 above, the amount of pigment mixed
When the pigment was increased by 0.005 part, the original color of the pigment was obtained at 60% humidity, but the colors when the pigment changed due to changes in humidity were all darker than those in the above examples.

Example 6 When the amount of cobalt chloride crystals was reduced to 0.7 parts compared to Examples 2 to 4 above, the range of change in each color became narrower, and screen prints (humidity indicators) that changed between 50 and 65% humidity were )was gotten.

Example 7 Next, cobalt chloride crystals were prepared in Examples 2 to 4 above.
When the amount was set at 1.5 parts, which is between the values of Example 6 and Example 6, the range of change in each color became wider, but the color became darker overall.

It can be seen from Examples 5 to 7 above that the color tone can be balanced at any humidity by changing the blending ratio of cobalt chloride and pigment.

Example 8 In the above example, a monochromatic screen print (humidity indicator) was formed using moisture-sensitive ink, but in this example, cobalt chloride
0.7 parts of water, 2 parts of water-absorbing powder, and 0.1 part of water-based pigment were mixed into each color of printing ink, using dark blue instead of black, 300 meshes, 60 lines,
Primary color printing was performed. At this time, a clean room where the temperature and humidity can be adjusted is set to 60% humidity and temperature.
The temperature was set at 20℃ to ensure proper color toning.

When the humidity reached 50%, the color tones were disrupted and the whole thing became darker, creating a psychedelic balance.

Conversely, when the humidity reached 70%, the colors became more intensely yellow and pink, the blues weakened, the sky took on a reddish tint, and the leaves on the trees turned yellow, creating an eerie appearance.

In the above examples, cobalt chloride was used as the moisture-sensitive basic dye, but the moisture-sensitive basic dye of the present invention includes cobalt bromide, rhodamine,
Crystal violet etc. can also be used.

[Effect of idea]

The printing ink used for the humidity indicator of the present invention is based on a humidity-sensitive basic dye.The humidity-sensitive basic dye is dissolved in water and absorbed into a water-absorbing powder to obtain an appropriate viscosity as a printing ink. Contains pigments or dyes. Therefore, even when performing multicolor printing, the tone and number of colors can be easily matched, and a well-balanced printed matter can be obtained.

In addition, since the screen-printed part of the humidity indicator of the present invention is screen-printed, the printed surface has many fine irregularities, the moisture-sensitive area is very large, and it is sensitive to ambient humidity. Contains a large amount of water-absorbing powder, which ensures the absorption of ambient humidity. For this reason, the screen printed matter of the present invention changes color quickly and has a large range of color change in response to changes in humidity.

In the present invention, a humidity indicator part is provided together with the screen-printed part, which is printed using ordinary paint to show the color tone that the screen-printed part exhibits at each relative humidity.The color tone of this screen-printed part is compared with the humidity indicator part. This allows you to easily know the humidity.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a solid screen printing state, and FIG. 2 is a plan view of an embodiment of the present invention. 1...Synthetic paper, 2...Screen printing, 3...
Plain punching, 4...Offset printing, 5...Screen printing part, 6...Humidity indicator part.

Claims (1)

[Scope of utility model registration request] A humidity indicator comprising a substrate and a printed portion formed on the substrate surface, the printed portion being characterized in that the printed portion is screen-printed using a printing ink obtained by absorbing a mixture of a moisture-sensitive basic dye and water into a water-absorbent powder, the screen-printed portion changing color depending on the relative humidity in the air, and a humidity indicator portion in which the color tone exhibited by the screen-printed portion at each relative humidity is printed using paint that does not change with humidity.