A low-voltage color-changing ink

Abstract

The present invention provides a low-voltage color-changing ink, which is composed of a pressure-sensitive color-changing ink and glass powder. The glass powder is made by crushing with a hammer mill. The glass before crushing the glass powder is heated to a softening temperature of 650 degrees Celsius, and then cooled at a cooling rate of 10 degrees Celsius per hour to 520 degrees Celsius, and then quenched and cooled to the temperature of an ice-water mixture. Such an operation can make the glass powder produce more sharp edges. Compared with ball milling, the glass powder crushed by a hammer mill has more edges and corners. The pressure-sensitive material is filled between the glass powders with edges and corners. When an external pressure is applied, a large pressure can be formed at the edge parts of the glass powder, reaching the pressure range for pressure-induced color change of the pressure-sensitive material.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and particularly to a low-pressure discoloring ink. Background Art

[0002] Adding pressure-sensitive materials to inks and utilizing the inherent property of pressure discoloration of pressure-sensitive materials have good application prospects in the field of anti-counterfeiting. The commonly used pressure-sensitive materials at present have a sensitive range of pressure from 1 to 5 Mpa. Intuitively, 1 - 5 Mpa is the pressure generated by 10 - 50 kgf acting on one square centimeter. This is rather difficult for application scenarios. Pressing an object of 50 kgf with a finger may cause fractures or sprains. Therefore, the discoloration application of pressure-sensitive materials often requires professional positive pressure devices, which limits the application of pressure-sensitive inks. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention attempts to overcome the above defects. Therefore, the present invention provides a low-pressure discoloring ink to solve the problem that pressure-sensitive inks require a large positive pressure to cause discoloration.

[0004] To achieve the above object, the present invention is realized through the following technical solutions: A low-pressure discoloring ink is composed of a pressure-sensitive discoloring ink and glass powder mixed together. The glass powder is made by crushing with a hammer mill.

[0005] Further, the glass powder is obtained by screening through a 1600 - 2000 mesh sieve. The glass powder that fails to pass the screening is put back into the hammer mill for crushing until it passes the screening.

[0006] Further, the glass before being crushed is heated to the softening temperature of 650 °C, then cooled at a cooling rate of 10 °C per hour to 520 °C, and then quenched and cooled to the temperature of an ice-water mixture.

[0007] Further, the volume ratio of the pressure-sensitive discoloring ink to the glass powder is 60%:40%.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] The glass before being crushed is heated to the softening temperature of 650 °C, then cooled at a cooling rate of 10 °C per hour to 520 °C, and then quenched and cooled to the temperature of an ice-water mixture. Such an operation can make the glass powder have more sharp edges. Compared with ball milling, the glass powder crushed by a hammer mill has more edges and corners. The pressure-sensitive material is filled between the glass powder with edges and corners. When an external pressure is applied, a large pressure can be formed at the edge parts of the glass powder, reaching the pressure range for the pressure-sensitive material to cause discoloration. Detailed Embodiments

[0010] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0011] The present invention provides a low-pressure color-changing ink, which is composed of a pressure-sensitive color-changing ink and glass powder. The glass powder is made by crushing with a hammer mill, and the glass powder is obtained by screening through a 1600-2000 mesh sieve. The glass powder that fails to pass the screening is put back into the hammer mill for crushing until it passes the screening. The glass before crushing is heated to the softening temperature of 650 degrees Celsius, then cooled at a cooling rate of 10 degrees Celsius per hour to 520 degrees Celsius, and then quenched and cooled to the temperature of an ice-water mixture. The volume ratio of the pressure-sensitive color-changing ink to the glass powder is 60%:40%.

[0012] Example 1

[0013] Prepare a pressure-sensitive ink, which changes color to yellow under a pressure of 5 Mpa. The ink is mixed with the glass powder of this application to make the ink of this application. The screen printing method is used for printing, and the hole size of the screen printing is 1000 mesh. A lead rod with a cross-sectional area of 1 square centimeter and a weight of 5 kilograms is made as a standard positive pressure source. The ink of this application is screen-printed on the surface of an aluminum plate to form an ink spot of 1.2 cm * 1.2 cm. After air drying, the standard positive pressure source is placed on the surface of the spot. After 10 seconds, the standard positive pressure source is removed, and the spot is photographed with a CCD, and the proportion of yellow pixels is extracted through a software algorithm.

[0014] Table 1 Measurement results under different ink-glass powder mixing ratios

[0015] Ink (volume percentage %) Glass powder (volume percentage %) Proportion of yellow pixels (%) 100 0 0 50 50 5.36 60 40 13.62

[0016] Table 2 Measurement results of glass powder obtained by different glass cooling methods

[0017]

[0018] Table 3 Measurement results of glass powder obtained by different sieve sizes

[0019] Glass powder obtained with different sieve sizes Proportion of yellow pixels (%) Glass powder of 1600 mesh 13.62 Glass powder of 2000 mesh 11.38

[0020] Example 2

[0021] Fabricate a lead rod with a cross-sectional area of 1 square centimeter and a weight of 5 kilograms as a standard positive pressure source. Sprinkle a layer of the glass powder of the present application with a thickness of d on the aluminum plate surface. Use the screen printing method to print a 1.2 cm * 1.2 cm ink spot with pressure-sensitive ink. After air drying, then place the standard positive pressure source on the surface of the ink spot. After 10 seconds, remove the standard positive pressure source, take a photo of the ink spot with a CCD, and extract the proportion of yellow pixels through software algorithms.

[0022] Table 4 Measurement results when a layer of the glass powder of the present application with a thickness of d is sprinkled on the aluminum plate surface

[0023] Thickness d (mm) of the glass powder of the present application Proportion of yellow pixels (%) 0.5-0.8 13.21 1.0-1.2 12.59

[0024] Working principle:

[0025] Heat the glass before pulverizing it to the softening temperature of 650 °C, then cool it at a cooling rate of 10 °C per hour to 520 °C, and then quench it to the temperature of an ice-water mixture. Such an operation can make the glass powder produce more sharp edges. Compared with ball milling, the glass powder crushed by a hammer mill has more edges and corners. The pressure-sensitive material is filled between the glass powder with edges and corners. When an external pressure is applied, a large pressure can be formed at the edge parts of the glass powder, reaching the pressure range for the pressure-sensitive material to change color under pressure.

[0026] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-voltage discoloring ink, characterized in that: It is composed of a mixture of pressure-sensitive color-changing ink and glass powder, and the glass powder is made by crushing with a hammer mill; The glass powder is obtained by screening through a 1600-2000 mesh sieve. The glass powder that fails to pass the screening is put back into the hammer mill for crushing until it passes the screening; The glass before crushing is heated to the softening temperature of 650 °C, then cooled at a cooling rate of 10 °C per hour to 520 °C, and then quenched and cooled to the temperature of an ice-water mixture; The volume ratio of the pressure-sensitive color-changing ink to the glass powder is 60%:40%; The characteristic of the pressure-sensitive color-changing ink is that it changes color to yellow under a pressure of 5 Mpa.

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