A label with radiation color-changing indication and radiation dose detection function, a preparation method thereof and a radiation dose detection method

Abstract

The present application belongs to the technical field of label printing or radiation sterilization, and particularly relates to a label with radiation color change indication and radiation dose detection, a preparation method thereof, and a radiation dose detection method. The preparation method of the label comprises the following steps: mixing thymol blue, alcohol, alcohol-soluble acrylic resin, a buffer solution, chloral hydrate, and a leveling agent to obtain composite ink; performing positioning and quantitative inkjet printing of the composite ink on the surface of an adhesive label, and drying to form an ink layer, thereby obtaining the label with radiation color change indication and radiation dose detection. The label can indicate whether the goods have undergone a sufficient dose of radiation according to the color change after radiation, and the size of the radiation dose can be obtained according to a radiation dose standard color chart. The label has good color consistency before and after undergoing the same dose of radiation, and the obtained radiation dose result is accurate and reliable.

Description

Technical Field

[0001] This invention belongs to the field of label printing or radiation sterilization technology, specifically relating to a label that combines radiation color change indication and radiation dose detection, its preparation method, and a method for detecting radiation dose. Background Technology

[0002] Radiation-changing labels are widely used in radiation processing, including sterilization and disinfection of various goods, preservation or storage of food, insect sterilization, modification of polymer materials, modification or radiation hardening of semiconductors, and radiation treatment of waste. The radiation source is generally an electron beam or Co. 60 The emitted gamma rays. With the continuous development of the radiation processing field, radiation-sensitive color-changing labels have broad application prospects.

[0003] Taking the application of radiation sterilization in food as an example, radiation sterilization has advantages such as minimal temperature rise, no alteration to the appearance, taste, or texture of food, no need to open packaging during radiation sterilization, and no addition of chemicals. The International Food Radiation Program (IFIP), jointly developed by the Food and Agriculture Organization of the United Nations (FAO), the International Atomic Energy Agency (IAEA), and the World Health Organization (WHO), states that radiation sterilization of food or pharmaceuticals is nutritionally and microbiologically safe when the overall average absorbed dose does not exceed 10 kGy. However, inappropriate radiation doses can destroy the nutrients in food; therefore, it is necessary to determine whether the product has undergone appropriate radiation doses as required.

[0004] In the production and management of radiation sterilization, radiation-changing labels are used to indicate whether goods have undergone radiation, and the radiation dose is measured using a radiation dosimeter. Typically, a radiation-changing label is a self-adhesive label that is yellow before irradiation and is affixed to the outer packaging of the irradiated goods. After irradiation, the label turns red, allowing visual inspection to determine whether the irradiated goods have undergone radiation sterilization. Commonly used radiation dosimeters for testing radiation dose include: red acrylic glass (model 4034, dose range: 5–50 kGy), amber acrylic glass (model 3042, dose range: 1–15 kGy), and gammachrome (model YR, dose range: 0.1–3 kGy); CTA film (model FTR-125, dose range: 10–100 kGy); and radiation-chromogenic film dosimeters (GEX B3, model FWT–60, dose range: 1–50 kGy). All these dosimeters require a matching spectrophotometer to measure the absorbance at a specific wavelength to obtain the radiation dose. The current radiation-changing labels exhibit inconsistent color depths from yellow to red during use, including poor color consistency before radiation exposure, poor storage stability, and inconsistent color after exposure to the same dose of radiation, leading to significant deviations in radiation dose test results. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a label that combines radiation color-changing indication and radiation dose detection, as well as a method for preparing the label and a method for detecting radiation dose. The label prepared by this invention has both radiation color-changing indication and radiation dose detection functions, and the label color has good stability and consistency, and the obtained radiation dose results are accurate and reliable.

[0006] This invention provides a method for preparing a tag that combines radiation color-changing indication and radiation dose detection, comprising the following steps:

[0007] A composite ink is obtained by mixing thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, chloral hydrate and leveling agent;

[0008] The composite ink is applied to the surface of the self-adhesive label using a positioning and quantitative inkjet printing process, and then dried to form an ink layer, resulting in the label that combines radiation color-changing indication and radiation dose detection.

[0009] Preferably, the alcohol is ethanol, and the mass ratio of thymol blue to ethanol is (0.08-0.12):100.

[0010] Preferably, the total mass ratio of the thymol blue and alcohol to the mass ratio of the alcohol-soluble acrylic resin is 100:(15-20).

[0011] Preferably, the ratio of the total mass of the thymol blue, alcohol, and alcohol-soluble acrylic resin to the amount of buffer solution is 1 kg: (8-12) mL.

[0012] Preferably, the total mass ratio of the thymol blue, alcohol, alcohol-soluble acrylic resin and buffer solution to chloral hydrate is 100:(8-12).

[0013] Preferably, the total mass ratio of the thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, and chloral hydrate to the leveling agent is 100:(0.3-0.8).

[0014] Preferably, the thickness of the ink layer is 35±2μm.

[0015] Preferably, the drying is performed by vacuum drying at room temperature.

[0016] The present invention also provides a label that combines radiation color-changing indication and radiation dose detection, obtained by the preparation method described above, including a self-adhesive label and an ink layer printed on the surface of the self-adhesive label, the ink layer including thymol blue, acrylic resin, buffer salt, chloral hydrate and leveling agent.

[0017] The present invention also provides a method for detecting radiation dose, comprising the following steps:

[0018] Provide a standard colorimetric card for radiation dose;

[0019] The irradiated label is compared with the radiation dose standard colorimetric card to obtain the radiation dose value; the irradiated label uses the label described in the above technical solution that combines radiation color change indication and radiation dose detection.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention provides a method for preparing a label that combines radiation color-changing indication and radiation dose detection, comprising the following steps: mixing thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, chloral hydrate and leveling agent to obtain a composite ink; performing positional and quantitative inkjet printing of the composite ink on the surface of a self-adhesive label, drying to form an ink layer, thereby obtaining the label that combines radiation color-changing indication and radiation dose detection.

[0022] This invention adds a buffer solution to the composite ink used in label preparation. After drying, the hydrogen ion concentration in the label ink layer remains stable within a certain range under the action of the buffer salt. During storage, chloral hydrate decomposes under heat, light, or other external energy, producing a small amount of hydrogen ions. The weak acid in the buffer salt reacts with its conjugate base to produce a conjugate acid, thereby reducing fluctuations in the free hydrogen ion concentration in the ink layer. This reduces the color change of the thymol blue indicator, improving the consistency of label color before and after radiation and the storage stability of the label color. This invention uses a fully soluble alcohol-based acrylic resin as the film-forming resin for the composite ink. After curing, it has high transparency and no particular absorption peak in the visible light wavelength range, eliminating the influence of the film-forming resin on the label color and color changes. Furthermore, this invention uses inkjet printing, which facilitates control over the consistency of the ink layer thickness, reducing the impact of varying ink layer thickness on color and further improving the consistency of label color. The label of this invention can indicate whether the goods have undergone a sufficient dose of radiation based on the color change after irradiation, and can also obtain the radiation dose according to the radiation dose standard color chart; the label of this invention has good color consistency before irradiation and after experiencing the same dose of radiation, and the obtained radiation dose results are accurate and reliable.

[0023] The present invention also provides a method for detecting radiation dose. The yellow color of the label before radiation and the red color after experiencing the same dose of radiation are highly consistent. It can not only indicate whether the processed goods have undergone sufficient radiation dose, but also obtain the radiation dose value at the radiation processing site using the standard color chart made therein, without the need to use a thin-film dosimeter and additional special spectrophotometer equipment. Detailed Implementation

[0024] This invention provides a method for preparing a tag that combines radiation color-changing indication and radiation dose detection, comprising the following steps:

[0025] A composite ink is obtained by mixing thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, chloral hydrate and leveling agent;

[0026] The composite ink is applied to the surface of the self-adhesive label using a positioning and quantitative inkjet printing process, and then dried to form an ink layer, resulting in the label that combines radiation color-changing indication and radiation dose detection.

[0027] Unless otherwise specified, all materials and equipment used in this invention are commercially available products in the field.

[0028] This invention mixes thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, chloral hydrate and leveling agent to obtain composite ink.

[0029] In this invention, the preferred method for mixing thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, chloral hydrate, and leveling agent is as follows: first, thymol blue is dissolved in alcohol, then alcohol-soluble acrylic resin is added, then buffer solution is added, then chloral hydrate is added, and finally leveling agent is added.

[0030] In this invention, the alcohol is preferably ethanol.

[0031] In this invention, the preferred mass ratio of thymol blue to alcohol is (0.08–0.12):100, more preferably 0.12:100. Thymol blue is an acid-base indicator; it is yellow at pH 2.8–8 and red at pH < 1.2, with the color changing with pH value.

[0032] In this invention, the alcohol-soluble acrylic resin is preferably a Keding alcohol-soluble resin ( MR10).

[0033] In this invention, the preferred mass ratio of the total mass of thymol blue and alcohol to the mass ratio of the alcohol-soluble acrylic resin is 100:(15-20), more preferably 100:18. This invention uses an alcohol-soluble acrylic resin as the film-forming resin for the composite ink, resulting in high transparency after curing and no particular absorption peak in the visible light wavelength range, thus eliminating the influence of the film-forming resin on the label color and color changes. Furthermore, the diffusion rate of hydrogen ions within the acrylic resin film is greater than that of other commonly used water-soluble substances, such as polyvinylpyrrolidone, thereby increasing the color-changing speed of the label under the action of hydrogen ions, i.e., improving the label's color-changing sensitivity. In addition, the use of an alcohol-soluble resin in this invention ensures that alcohol can be used alone as a solvent for the composite ink. The fast evaporation rate of alcohol allows for faster drying under low-temperature vacuum conditions, avoiding the influence of heat drying on chloral hydrate (chloral hydrate decomposes slightly to produce hydrogen ions at temperatures above 40°C).

[0034] The alcohol-soluble acrylic resin is dissolved in ethanol, and after forming a film alone, the visible light transmittance is above 98%, especially with no absorption at wavelengths of 445 nm and 553 nm. The alcohol-soluble acrylic resin of this invention forms a colorless and transparent film, which is more transparent than polyvinyl butyral resin, and can improve the color response of thymol blue to changes in hydrogen ion concentration, thereby improving the color change sensitivity.

[0035] In this invention, the buffer solution is preferably a buffer solution with pH=3.5 or pH=5, more preferably a buffer solution with pH=3.5. The method for preparing the pH=3.5 buffer solution preferably includes: dissolving 25g of ammonium acetate in 25mL of water, adding 38mL of 7mol / L hydrochloric acid solution, accurately adjusting the pH to 3.5 with 2mol / L hydrochloric acid solution, and diluting with water to 100mL. The buffering capacity of the pH=3.5 buffer solution makes it easier to control the consistency of the label color before and after radiation.

[0036] In this invention, the ratio of the total mass of the thymol blue, alcohol, and alcohol-soluble acrylic resin to the amount of buffer solution is preferably 1 kg:(8-12) mL, more preferably 1 kg:10 mL.

[0037] This invention adds a buffer solution with pH=3.5 to the composite ink. After drying, the hydrogen ion concentration in the label ink layer remains stable within a certain range under the action of the buffer salt. During storage, chloral hydrate decomposes under heat, light, or other external energy, producing a small amount of hydrogen ions. The weak acid in the buffer salt reacts with its conjugate base to produce a conjugate acid, thereby reducing fluctuations in the free hydrogen ion concentration in the ink layer and stabilizing it. This reduces the impact of ambient temperature and humidity on the label color. Thymol blue is an acid-base indicator; a small change in hydrogen ion concentration in the ink layer results in a small change in color. Adding a buffer solution to the composite ink significantly improves the consistency and storage stability of the label color.

[0038] When chloral hydrate in the ink layer is exposed to high-energy particles such as electron beams or gamma rays, it will generate a large number of hydrogen ions. Under these conditions, the amount of hydrogen ions generated exceeds the buffering capacity provided by the buffer salt, causing the pH value of the ink layer to change, which in turn leads to a change in the label color.

[0039] In this invention, the mass ratio of the total mass of thymol blue, alcohol, alcohol-soluble acrylic resin, and buffer solution to chloral hydrate is preferably 100:(8-12), more preferably 10:1. Chloral hydrate generates a large number of hydrogen ions after irradiation, causing a change in the pH value of the label, which in turn leads to a change in the label color.

[0040] In this invention, the leveling agent preferably comprises a polyether-modified polyorganosiloxane leveling agent.

[0041] In this invention, the mass ratio of the total mass of thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution and chloral hydrate to the mass of leveling agent is preferably 100:(0.3-0.8), more preferably 100:0.5.

[0042] In this invention, the surface tension of the composite ink is preferably 23-28 mN / cm. This surface tension allows the composite ink to flow and level quickly on self-adhesive label paper, thus ensuring the consistency of the ink layer thickness after quantitative inkjet printing. The pH value of the composite ink is preferably around 3.5.

[0043] In the actual preparation process, the amount of each substance in the composite ink is a fixed value, rather than a certain range, to ensure the color consistency between the labels before and after irradiation.

[0044] After obtaining the composite ink, the present invention performs positional and quantitative inkjet printing on the surface of the self-adhesive label, and dries it to form an ink layer, thereby obtaining the label that combines radiation color change indication and radiation dose detection.

[0045] In this invention, the self-adhesive label includes printed text information, such as the name of the processed goods, the name of the radiation processing manufacturer, and the date.

[0046] In this invention, the inkjet-printed pattern is preferably a circular solid pattern, the diameter of which is preferably 12.7 ± 0.05 mm, the ink consumption for each circular solid pattern is preferably 140 ± 5 mg, and the ink layer thickness is preferably 35 ± 2 μm. This invention uses a positional and quantitative inkjet printing method to prepare the pattern, which, compared to other methods such as coating or screen printing, produces a more consistent ink layer thickness, thereby reducing the impact on color chromaticity values ​​caused by variations in ink layer thickness. Furthermore, the preparation process is simple.

[0047] In this invention, the drying is preferably room temperature vacuum drying. This invention does not use heating drying, but room temperature vacuum drying, which reduces the impact of hydrogen ions generated by the decomposition of chloral hydrate under heat on the label color and maintains the consistency of label color change.

[0048] In this invention, the drying process preferably includes die-cutting, and there are no special requirements for the die-cutting in this invention.

[0049] In this invention, the label is preferably sealed in a plastic bag and stored at a temperature below 8°C, a relative humidity of 35%–45%, and in the dark. This invention employs refrigeration and light-protected storage, reducing the impact of hydrogen ions generated by the decomposition of chloral hydrate under heat or light on the label color.

[0050] In the actual preparation process, the ink layer thickness is a fixed value. The drying method and storage conditions before radiation described in this invention further ensure the color consistency between the labels before and after radiation.

[0051] The present invention also provides a label that combines radiation color-changing indication and radiation dose detection, obtained by the preparation method described above, including a self-adhesive label and an ink layer printed on the surface of the self-adhesive label, the ink layer including thymol blue, acrylic resin, buffer salt, chloral hydrate and leveling agent.

[0052] In this invention, the ink layer is preferably a circular solid pattern, and the diameter of the circular solid pattern is preferably 12.7 ± 0.05 mm.

[0053] The present invention also provides a method for detecting radiation dose, comprising the following steps:

[0054] Provide a standard colorimetric card for radiation dose;

[0055] The irradiated label is compared with the radiation dose standard colorimetric card to obtain the radiation dose value; the irradiated label uses the label described in the above technical solution that combines radiation color change indication and radiation dose detection.

[0056] This invention provides a radiation dose standard colorimetric card.

[0057] In this invention, the radiation dose standard colorimetric card is prepared by a method comprising the following steps:

[0058] The tag is irradiated at a set radiation dose, and the L*, a*, and b* values ​​of the tag are tested after irradiation; the tag is the tag described in the above technical solution that combines radiation color-changing indication and radiation dose detection.

[0059] Based on the L*, a*, and b* values, obtain standard color blocks under the set radiation dose in the drawing software;

[0060] The standard color blocks at the set radiation dose are inkjet printed to obtain a radiation dose standard colorimetric card.

[0061] In this invention, the set radiation dose preferably includes: 0.5 kGy, 1.0 kGy, 1.5 kGy, 2.0 kGy, 2.5 kGy, 3.0 kGy, 3.5 kGy, 4.0 kGy, 4.5 kGy, 5.0 kGy, 5.5 kGy, 6.0 kGy, 6.5 kGy, 7.0 kGy, 7.5 kGy, 8.0 kGy, 8.5 kGy, 9.0 kGy, 9.5 kGy, 10.0 kGy, 11.0 kGy, and 12.0 kGy. kGy, 13.0kGy, 14.0kGy, 15.0kGy, 16.0kGy, 17.0kGy, 18.0kGy, 19.0kGy, 20kGy, 21.0kGy, 22.0kGy, 23.0k Gy, 24.0kGy, 25.0kGy, 26.0kGy, 27.0kGy, 28.0kGy, 29.0kGy, 30kGy, 32kGy, 34kGy, 36kGy, 38kGy and 40kGy.

[0062] In this invention, the equipment used for radiation is preferably from IBA Company in Belgium. The TT200 electron accelerator preferably includes the following functional parameters: energy 10MeV, beam current 5mA, and power 50kW.

[0063] In this invention, color is described using L*, a*, and b* values. The L* value generally ranges from 0 to 100, representing the brightness of an object; a higher value indicates a brighter object. The a* value ranges from +127 to -128. A value of +127 represents magenta, while a transition from positive to negative values ​​indicates a shift towards green. The b* value also ranges from +127 to -128. A value of +127 represents yellow, while a value of -128 represents blue; values ​​in between represent transitional colors. The L*, a*, and b* values ​​(chromaticity values) are measured using a spectrophotometer, specifically an Eye-one iSis spectrophotometer.

[0064] In this invention, the label is irradiated at a set radiation dose, and the L*, a*, and b* values ​​of the irradiated label are tested. Based on the L*, a*, and b* values, a standard color block at the set radiation dose is obtained in drawing software. Specifically, a commercially available GEX B3 dosimeter is used to calibrate the radiation dose and obtain the standard color block. Taking a radiation dose of 0.5 kGy as an example, the device is set to a radiation dose of 0.5 kGy. The GEX B3 dosimeter is irradiated, and the irradiated GEX B3 dosimeter is measured using a matching spectrophotometer. Each absorbance corresponds to a dose. The dose value measured by the GEX B3 dosimeter deviates from the device's set dose value of 0.5 kGy. Based on the magnitude of the deviation, the beam current and power of the electron accelerator are adjusted to make the GEX B3 dosimeter measurement value the same as the set radiation dose, both being 0.5 kGy. Thus, the device's radiation dose is an accurate 0.5 kGy. Then, the 10 tags prepared according to this invention were irradiated together with a GEX B3 radiation dosimeter at a calibrated equipment radiation parameter of 0.5 kGy. The dose obtained by the GEX B3 radiation dosimeter after irradiation was 0.5 kGy. The L*, a*, and b* color values ​​of these 10 tags after irradiation were measured using an X-Rite Eye-one iSis spectrophotometer. The three tags with the smallest difference in color values ​​were selected, and the average value was taken. Based on the average value of L*, a*, and b*, a 0.5 kGy color block was obtained in the drawing software PS or AI, which was called the 0.5 kGy standard color block. The method for obtaining the other radiation dose standard color blocks was the same.

[0065] In this invention, the inkjet printing preferably uses four-color inkjet inks, and the amount of ink used for each standard color block is the same as the amount of ink used when preparing a single label. The standard color blocks are preferably inkjet printed on white cardstock, and the standard color blocks are preferably circular solid color blocks, with a diameter preferably of 12.7 ± 0.05 mm.

[0066] The present invention does not have any special requirements for the method of comparing the label to be irradiated with the radiation dose standard colorimetric card.

[0067] The label of this invention exhibits good color consistency before and after exposure to the same dose of radiation. The shades of red in the label after radiation show a one-to-one correspondence with the radiation dose. Based on this, after the label is exposed to different doses of radiation, the chromaticity values ​​L*, a*, and b* of the label color after each dose of radiation are measured using a spectrophotometer. Standard color blocks corresponding to the corresponding doses are then created based on these chromaticity values. This process is repeated to obtain a series of standard color blocks corresponding to different radiation doses, which are then printed as a radiation dose standard colorimetric card. In this way, the color change after radiation can indicate whether the goods have undergone a sufficient dose of radiation, while the actual radiation dose can be obtained using the radiation dose standard colorimetric card.

[0068] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, describes the label that combines radiation color-changing indication and radiation dose detection, its preparation method, and the radiation dose detection method provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0069] Example 1

[0070] A method for preparing a tag that combines radiation color-changing indication and radiation dose detection, and a method for detecting radiation dose, comprising the following steps:

[0071] The first step is to dissolve thymol blue in ethanol. After complete dissolution, filter the solution, resulting in a thymol blue content of 0.12% (0.12g thymol blue per 100g ethanol). Then, add ethanol-soluble acrylic resin to the above solution. MR acrylic resin), wherein the mass of the acrylic resin is 18% of the mass of the above solution.

[0072] The second step involves adding a buffer solution with pH=3.5. The buffer solution is prepared as follows: Dissolve 25g of ammonium acetate in 25mL of water, then add 38mL of 7mol / L hydrochloric acid solution. Adjust the pH to 3.5 using 2mol / L hydrochloric acid solution, and dilute with water to 100mL. While stirring, add 10mL of the pH=3.5 buffer solution to each kilogram of ink obtained in the first step. The solution will turn bright yellow.

[0073] The third step involves adding 10% chloral hydrate by weight of the ink from the second step; the pH value of the ink is then stabilized at around 3.5.

[0074] The fourth step involves adding 0.5% by mass of polyether-modified polysiloxane leveling agent to the ink from the third step to obtain a composite ink with a surface tension of 23–28 mN / cm.

[0075] The fifth step is to perform positional and quantitative inkjet printing. After the text information on the self-adhesive label has been printed, a circular solid pattern with a diameter of 12.70 mm is positioned and printed at the designated location on the label. The inkjet printer is set to use 140±5 mg of ink for each circular pattern, and the ink layer thickness after drying is 35±2 μm.

[0076] Step 6: Vacuum drying at room temperature.

[0077] Step 7: Die-cut to obtain self-adhesive labels with radiation color-changing indication and radiation dose detection function patterns on the surface. These labels combine radiation color-changing indication and radiation dose detection. After sealing in a plastic bag, store at a temperature below 8°C, relative humidity of 35% to 45%, and away from light.

[0078] Step 8: Create a standard colorimetric chart that corresponds to the radiation dose and the color after radiation discoloration.

[0079] The radiation equipment used was from IBA Company in Belgium. The TT200 electron accelerator (functional parameters: energy 10MeV, beam current 5mA, power 50kW) was used to calibrate the prepared tags using a commercially available GEX B3 radiation dosimeter.

[0080] First, set the radiation dose parameters of the radiation equipment as follows: 0.5 kGy, 1.0 kGy, 1.5 kGy, 2.0 kGy, 2.5 kGy, 3.0 kGy, 3.5 kGy, 4.0 kGy, 4.5 kGy, 5.0 kGy, 5.5 kGy, 6.0 kGy, 6.5 kGy, 7.0 kGy, 7.5 kGy, 8.0 kGy, 8.5 kGy, 9.0 kGy, 9.5 kGy, 10.0 kGy, 11.0 kGy, 12.0 kGy. Gy, 13.0kGy, 14.0kGy, 15.0kGy, 16.0kGy, 17.0kGy, 18.0kGy, 19.0kGy, 20kGy, 21.0kGy, 22.0kGy, 23.0k Gy, 24.0kGy, 25.0kGy, 26.0kGy, 27.0kGy, 28.0kGy, 29.0kGy, 30kGy, 32kGy, 34kGy, 36kGy, 38kGy and 40kGy.

[0081] The radiation dose was calibrated using a commercially available GEX B3 dosimeter, and standard color blocks were obtained. Taking a radiation dose of 0.5 kGy as an example, the device was set to a radiation dose of 0.5 kGy. The GEX B3 dosimeter was irradiated, and the irradiated dose was measured using a matching spectrophotometer. Each absorbance corresponds to one dose. The dose value measured by the GEX B3 dosimeter deviated slightly from the device's set dose value of 0.5 kGy. Based on the magnitude of the deviation, the beam current and power of the electron accelerator were adjusted to ensure that the GEX B3 dosimeter reading matched the set radiation dose of 0.5 kGy. Thus, the device's radiation dose was accurately 0.5 kGy. Then, the 10 tags prepared in Example 1 were irradiated together with the GEX B3 dosimeter at the calibrated device radiation parameters of 0.5 kGy. The dose obtained by the irradiated GEX B3 dosimeter was 0.5 kGy. The L*, a*, and b* color values ​​of these 10 labels were measured using an X-Rite Eye-one iSis spectrophotometer after radiation. The three labels with the smallest difference in color values ​​were selected, and their average value was calculated. Based on the average L*, a*, and b* values, a 0.5 kGy color patch with a diameter of 12.70 mm was obtained in the graphic design software Photoshop. This circle was called the 0.5 kGy standard color patch.

[0082] Repeat this process to obtain standard color patches for the remaining radiation doses.

[0083] Standard color blocks corresponding to each radiation dose were quantitatively inkjet printed on white cardstock. Four-color inkjet ink was used. The total amount of ink used for each standard color block was the same as the amount of ink used when preparing a single label in Example 1. The color blocks on the label were also solid circular color blocks with a diameter of 12.7 mm, thus obtaining a radiation dose standard colorimetric card.

[0084] The ninth step is to compare the color of the irradiated label with a standard colorimetric card to obtain an accurate radiation dose value.

[0085] The inventors inkjet-printed composite ink onto a glass slide, dried it, and peeled off the film. The absorption spectrum of the film was then measured using a UV-Vis spectrophotometer. The unirradiated film showed a maximum absorption peak at 445 nm and no absorption peak at 553 nm. After being exposed to different doses of radiation, the film's absorption spectrum changed. The absorption peak at 445 nm decreased with increasing radiation dose, while the absorption peak at 553 nm increased with increasing radiation dose. As the radiation dose increased, this was reflected in the label color as a decrease in yellow hue and an increase in red hue. Therefore, there is a one-to-one correspondence between the color value of the label after radiation and the radiation dose. When using the label, it can be affixed to the outside of the product packaging. After being exposed to the radiation processing dose, the label will show a noticeable color change. Comparing the color-changed label with a standard color chart yields a quantitative value of the radiation dose. This eliminates the need for dedicated dose detection equipment; simply comparing the color of the irradiated label with a standard color chart provides the radiation dose value. The label of this invention combines radiation color-changing indication and radiation dose detection functions.

[0086] The label sample prepared in Example 1 was irradiated under the same radiation environment as a commercially available radiation film dosimeter (GEX B3 radiation dosimeter from Far West Corporation, USA). The radiation doses of the irradiation equipment were set to 0.5 kGy, 1 kGy, 3 kGy, 5 kGy, 10 kGy, 20 kGy, 30 kGy, and 40 kGy, respectively. After irradiation, the label of Example 1 gradually changed from its original yellow color to red and then purple as the radiation dose increased. The color change allowed for visual observation of whether the irradiated goods had undergone radiation treatment.

[0087] The irradiated labels were compared with the radiation dose standard colorimetric card prepared in Example 1 to obtain the radiation dose quantification value, as shown in Table 1.

[0088] Table 1. Results of equipment-set dose, commercially available dosimeter test dose, label of this invention test dose, and post-irradiation color values ​​L*, a*, and b*.

[0089]

[0090] As can be seen, the label of the present invention has radiation color-changing indication function and radiation dose detection function.

[0091] Comparative Example 1

[0092] The difference from Example 1 is that the second step (i.e., the addition of a buffer solution with pH=3.5) is not performed, while the remaining steps are the same as in Example 1.

[0093] Color difference values ​​are derived from L*a*b* values. The colors of two objects are represented by L*a*b* values, and comparing the two will produce three differences: ΔL*, Δa*, and Δb*. These differences are then calculated using the color difference formula to obtain the specific color difference ΔE*. Lab The calculation formula is shown below:

[0094]

[0095] The difference in how the human eye perceives two colors can be represented by color difference values ​​within a certain range, as shown in Table 2:

[0096] Table 2 Color Difference Values ​​and Human Visual Sensitivity

[0097] Unit color difference value (absolute value) Perceived color difference 0.0～0.5 The sensation is extremely subtle. 0.5～1.51 Slight sensation 1.5～3 Upon close observation, one can perceive the color change. 3～6 It feels very obvious 6~above Strong feeling

[0098] The labels prepared in Example 1 and Comparative Example 1 were tested below:

[0099] 1. Comparison of color storage stability of labels before radiation

[0100] Generally, prepared radiation color-changing indicator labels have a storage period before use. After a period of storage, the color-changing effect of the radiation label is very important.

[0101] Five labels from Example 1 and five labels from Comparative Example 1 were randomly selected and stored in a dark environment with a relative humidity of 40% and a temperature of 25%. Their color values ​​were tested periodically. For each test, different test points were selected from the same label and compared with the color values ​​of the label before irradiation. The average color difference value was calculated.

[0102] Table 3 shows the storage stability results of Comparative Example 1 without buffer solution labeling.

[0103]

[0104] Table 4. Storage stability results of the tag in Example 1

[0105]

[0106]

[0107] As shown in Tables 3 and 4, after 60 days of storage, the average color difference between the labels without added buffer solution and freshly prepared labels reached 2.42, indicating a slight color change to the human eye. However, after 60 days of storage, the average color difference between the labels with added pH buffer solution and freshly prepared labels was only 0.59, less than 1, showing almost no visual change. This demonstrates that adding pH buffer solution in this invention significantly improves the storage stability of the labels.

[0108] 2. Comparison of color consistency of labels before radiation

[0109] The method for evaluating the uniformity of the same type of label is as follows: Six labels of the same type are randomly selected, and their L*, a*, and b* values ​​are measured using an X-Rite spectrophotometer. The chromaticity value of one label is used as the standard value. The L*, a*, and b* values ​​of the remaining five labels are subtracted from this standard value to obtain ΔL*, Δa*, and Δb* values. ΔE* is then calculated using the color difference formula. Lab The results are shown in Table 5.

[0110] Table 5. Color differences among yellow labels before radiation discoloration.

[0111]

[0112] It can be seen that the label with added pH buffer solution in Example 1 has better color consistency (uniformity) than the label without added pH buffer solution and the commercially available GEX B3 radiation dosimeter (film).

[0113] 3. Comparison of color consistency (uniformity) of labels after exposure to different doses of radiation.

[0114] The label in Comparative Example 1 and similar commercially available labels showed similar color uniformity before radiation. Therefore, this invention selected the label in Example 1 and a commercially available GEX B3 radiation dosimeter (film) as evaluation objects.

[0115] Six samples from each of the two label types were randomly selected and subjected to radiation at 0.5 kGy, 3.0 kGy, 10 kGy, 20 kGy, 30 kGy, and 40 kGy, respectively. After radiation, the L*, a*, and b* values ​​were measured using an X-Rite spectrophotometer. Similarly, the chromaticity value of one label was used as the standard value. The L*, a*, and b* values ​​obtained from the tests of the other five labels were subtracted from this standard value to obtain the ΔL*, Δa*, and Δb* values. ΔE* was then calculated using the color difference formula. Lab The results are shown in Tables 6 and 7.

[0116] Table 6. Color difference test results of commercially available GEX B3 radiation dosimeter film after exposure to different doses of radiation.

[0117]

[0118] Table 7. Color difference test results of labels in Example 1 after exposure to different doses of radiation.

[0119]

[0120] It can be seen that the present invention improves the color consistency of the label before and after irradiation by adding a pH buffer solution.

[0121] This invention provides a label that combines radiation color-changing indication and radiation dose detection. The invention first prepares a composite ink with a pH value of approximately 3.5, which is yellow. After inkjet printing and vacuum drying, the chloral hydrate in the label generates hydrogen ions under radiation, causing the pH value of the ink layer to drop below 1.2 and turn red. The amount of hydrogen ions generated by chloral hydrate increases linearly with the radiation dose; the higher the radiation dose, the more hydrogen ions are generated, the lower the pH value of the ink layer, and the deeper the red color. This invention maintains stability in the composite ink formulation, pH value, and ink layer thickness, thus ensuring high consistency in color change before and after radiation, improving the accuracy of both radiation color-changing indication and radiation dose detection.

[0122] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a tag that combines radiation color-changing indication and radiation dose detection, characterized in that, Includes the following steps: A composite ink is obtained by mixing thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, chloral hydrate and leveling agent; The composite ink is applied to the surface of the self-adhesive label using a positioning and quantitative inkjet printing process, and then dried to form an ink layer, resulting in the label that combines radiation color-changing indication and radiation dose detection.

2. The preparation method according to claim 1, characterized in that, The alcohol is ethanol, and the mass ratio of thymol blue to ethanol is (0.08-0.12):

100.

3. The preparation method according to claim 1 or 2, characterized in that, The total mass ratio of the thymol blue and alcohol to the mass ratio of the alcohol-soluble acrylic resin is 100:(15-20).

4. The preparation method according to claim 1, characterized in that, The ratio of the total mass of the thymol blue, alcohol, and alcohol-soluble acrylic resin to the amount of buffer solution is 1 kg: (8-12) mL.

5. The preparation method according to claim 1, characterized in that, The total mass ratio of thymol blue, alcohol, alcohol-soluble acrylic resin and buffer solution to chloral hydrate is 100:(8-12).

6. The preparation method according to claim 1, characterized in that, The total mass ratio of thymol blue, alcohol, alcohol-soluble acrylic resin, buffer solution, and chloral hydrate to the leveling agent is 100:(0.3-0.8).

7. The preparation method according to claim 1, characterized in that, The thickness of the ink layer is 35±2μm.

8. The preparation method according to claim 1 or 7, characterized in that, The drying process is a vacuum drying process at room temperature.

9. The label obtained by the preparation method according to any one of claims 1 to 8, which combines radiation color-changing indication and radiation dose detection, is characterized in that, The invention includes self-adhesive labels and an ink layer printed on the surface of the self-adhesive labels, the ink layer comprising thymol blue, acrylic resin, buffer salt, chloral hydrate and leveling agent.

10. A method for detecting radiation dose, characterized in that, Includes the following steps: Provide a standard colorimetric card for radiation dose; The irradiated label is compared with the radiation dose standard colorimetric card to obtain the radiation dose value; the irradiated label is the label with both radiation color change indication and radiation dose detection as described in claim 9.

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