A temperature-sensitive smart tag

Abstract

This utility model discloses a temperature-sensitive intelligent tag, belonging to the field of tag technology. The tag body has a multi-layer structure, consisting of a temperature-sensitive ink layer, an RFID functional layer, an adhesive layer, and a release liner from top to bottom. The temperature-sensitive ink layer is a thin film, with its lower surface tightly bonded to the upper surface of the RFID functional layer via a water-based adhesive. The RFID functional layer uses PET film as its substrate, and the area on the upper surface of the substrate that carries electronic components has an insulating coating. The adhesive layer is a continuously coated, uniform adhesive layer, fully bonded to the lower surface of the RFID functional layer on one side, and peelably bonded to the release liner on the other side. The release liner is made of glassine paper with a strength of 80–120 g / m². This tag combines temperature sensing and RFID technology, has a reasonable structural design, adheres firmly, is easy to use, and is suitable for temperature monitoring in logistics, warehousing, and other scenarios.

Description

Technical Field

[0001] This utility model relates to the field of label technology, specifically to a temperature-sensing intelligent label. Background Technology

[0002] In the field of temperature monitoring for single-use packaging scenarios such as logistics and warehousing, existing temperature monitoring labels have significant technical limitations. Traditional temperature-sensitive labels mainly rely on the color change of temperature-sensitive ink to indicate temperature. Although they can visually identify temperature anomalies, they can only provide real-time status display, cannot record temperature change data, and do not have remote monitoring capabilities. They require manual inspection one by one, which is inefficient and prone to omissions.

[0003] Another type of RFID temperature tag, while capable of data recording and remote transmission, relies on independent electronic sensors for temperature detection. This not only leads to higher overall tag costs but also results in higher power consumption for electronic components, making it difficult to meet the low-cost requirements of single-use packaging scenarios such as logistics and warehousing. Furthermore, existing technologies lack a solution that organically integrates the intuitive visualization advantages of temperature-sensitive ink with the automated data management capabilities of RFID. These two technologies have long been used independently, failing to form a complementary and integrated solution.

[0004] In addition, there is room for optimization in the structural design of existing labels: traditional temperature-sensitive labels lack a protective structure for the functional layer, and the ink is easily rubbed off due to friction and squeezing; if the electronic components of RFID tags lack insulation protection, their stability may be affected by environmental moisture and impurities; and structural details such as the reliability of the label-packaging fit and ease of use have not yet formed a mature design suitable for disposable packaging scenarios. Utility Model Content

[0005] The purpose of this utility model is to provide a temperature-sensing intelligent tag to solve the defects of existing similar products. This tag combines temperature sensing and RFID technology, has a reasonable structural design, fits firmly, is easy to use, and is suitable for temperature monitoring in logistics, warehousing and other scenarios.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a temperature-sensitive intelligent tag, comprising a tag body, the tag body having a multi-layer structure, the multi-layer structure comprising, from top to bottom, a temperature-sensitive ink layer, an RFID functional layer, an adhesive layer, and a release liner, wherein the temperature-sensitive ink layer is a thin film structure, its lower surface being tightly bonded to the upper surface of the RFID functional layer by a water-based adhesive; the RFID functional layer uses PET film as a substrate, and an insulating coating is provided on the upper surface of the substrate where electronic components are carried; the adhesive layer is a continuously coated uniform adhesive layer, one side of which is completely bonded to the lower surface of the RFID functional layer, and the other side is peelably bonded to the release liner; the release liner is made of glassine paper with a strength of 80-120 g / m².

[0007] To further optimize this utility model, the following technical solutions may be preferred:

[0008] Preferably, the ink in the temperature-sensitive ink layer contains reversible thermochromic microcapsules with a diameter of <100μm, and the shell of the microcapsules is made of gelatin or polyurethane material.

[0009] Preferably, the core color-changing material of the reversible thermochromic microcapsule includes a leuco dye, a color developer, and a temperature-sensitive medium; the color developer is bisphenol A or a phenolic compound; the leuco dye is crystal violet lactone (CVL) or spiropyran; and the temperature-sensitive medium is a low-melting-point long-chain alcohol.

[0010] Preferably, the RFID functional layer includes a conductive ink antenna and an RFID chip; the antenna is made of conductive ink using printing technology, and a temperature-sensitive resistive element is integrated on the antenna layer; the RFID chip records temperature data through changes in the resistive element.

[0011] Preferably, the color change threshold of the temperature-sensitive ink layer is synchronized with the temperature alarm threshold of the RFID chip; when the temperature is greater than the set value, the ink layer changes color, and at the same time, the change in the resistance value of the RFID chip triggers the alarm tag bit.

[0012] Preferably, the temperature-sensitive ink layer is screen-printed onto the label film; the antenna of the RFID functional layer is a silver paste antenna and is attached with an RFID chip; the adhesive layer is an acrylic pressure-sensitive adhesive layer.

[0013] The beneficial effects of this utility model are mainly reflected in the following aspects:

[0014] (1) In terms of functional integration, it effectively solves the limitations of traditional temperature-sensitive tags and RFID temperature tags. By integrating the temperature-sensitive ink layer and the RFID functional layer into the multi-layer structure of the same tag, it not only retains the intuitiveness of the color change of the temperature-sensitive ink, allowing staff to quickly judge temperature abnormalities visually, but also realizes temperature data recording and remote monitoring with the help of RFID function, eliminating the need for manual inspection of each tag, greatly improving the efficiency of temperature monitoring, and avoiding the problem of easy omissions during manual inspection of traditional temperature-sensitive tags.

[0015] (2) In terms of cost control, it has a greater advantage than RFID temperature tags that rely on independent electronic sensors. This tag uses the physical color-changing properties of temperature-sensitive ink to assist in temperature monitoring, reducing the reliance on electronic sensors and lowering the overall cost; at the same time, the RFID functional layer uses printing technology to make antennas and other designs, which also helps to control costs and make it suitable for the low-cost needs of single-use packaging scenarios such as logistics and warehousing.

[0016] (3) In terms of structural reliability, the multi-layer structure design and the connection method of each layer bring good performance. The temperature-sensitive ink layer is tightly bonded to the RFID functional layer through water-based adhesive. The RFID functional layer uses PET film as the substrate and sets an insulating coating in the electronic component area, which can reduce the damage to the functional layer caused by friction and extrusion, as well as the impact of environmental moisture and impurities on the electronic components. The adhesive layer adopts a continuously coated uniform adhesive layer, combined with 80-120g / m² glassine paper release paper, which makes the label firmly attached and easy to peel off and attach when used, improving the applicability of the label in logistics and other scenarios.

[0017] Furthermore, the synchronized design of the temperature-sensitive ink layer and the RFID functional layer at temperature thresholds ensures that when the temperature exceeds the set value, the ink layer color development and the RFID chip alarm trigger simultaneously, achieving dual alerts and further improving the accuracy and reliability of temperature monitoring. The application of optimized solutions such as screen printing, silver paste antennas, and acrylic pressure-sensitive adhesives also guarantees the stability of the label's performance in terms of both process and materials. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the smart tag of this utility model.

[0019] In the diagram: 1 - Temperature-sensitive ink layer, 2 - RFID functional layer, 3 - Adhesive layer, 4 - Release paper backing paper, 5 - Water-based adhesive, 6 - Abrasion-resistant protective layer, 7 - Temperature-sensitive ink body, 8 - PET carrier film, 9 - PET substrate, 10 - Insulating coating, 11 - Electronic component area, 12 - Aluminum foil shielding ring. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this utility model.

[0022] Example 1:

[0023] I. Overall Structure and Material Selection

[0024] A temperature-sensitive indicator smart tag is provided. In this embodiment, the temperature-sensitive indicator smart tag has a multi-layer composite structure, consisting of a temperature-sensitive ink layer 1, an RFID functional layer 2, an adhesive layer 3, and a release paper backing 4, from top to bottom. The structure and materials of each layer are selected as follows:

[0025] Release paper backing 4: 100g / m² glassine paper with silicone release treatment on the surface to ensure peelability to the adhesive layer and good tear resistance, suitable for packaging operations in logistics and transportation.

[0026] Adhesive layer 3: Acrylic pressure-sensitive adhesive is continuously coated onto the release liner using a roller coating process. The adhesive layer thickness is controlled at 20μm, and the coating uniformity error is ≤±2μm. This adhesive layer has a holding power of ≥24h at 25℃, ensuring that the label is not easily detached after being applied to the packaging surface, and leaving no adhesive residue upon peeling.

[0027] RFID functional layer: A 30μm thick PET film is used as the substrate, which has good temperature resistance (no deformation from -20℃ to 60℃) and mechanical strength. On the electronic component carrying area on the upper surface of the substrate, a 0.5μm thick insulating coating (using epoxy resin) is first formed through a coating process to isolate moisture and impurities in the environment and prevent short circuits in electronic components.

[0028] Temperature-sensitive ink layer: It is an 8μm thick film structure, which is made on a PET film carrier by screen printing. Its lower surface is tightly bonded to the upper surface of the RFID functional layer by a 1μm thick water-based adhesive 5 (acrylate). The bonding strength is ≥0.3N / cm, ensuring that the two layers will not separate under friction and vibration.

[0029] II. Manufacturing Process of Key Functional Layers

[0030] Preparation of temperature-sensitive ink layer

[0031] Ink formulation: Water-based polyurethane resin is used as the base material, and reversible thermochromic microcapsules 6 (accounting for 30% of the total ink mass) are added. The diameter of the microcapsules is controlled at 50-80μm (to ensure that the mesh is not easily blocked during printing).

[0032] Microcapsule parameters: The outer shell is made of gelatin material, and the color-changing material of the core is composed of crystal violet lactone (CVL, accounting for 20% of the core mass), bisphenol A (accounting for 30% of the core mass) and hexadecyl alcohol (low melting point long chain alcohol, accounting for 50% of the core mass). The melting point of hexadecyl alcohol is 49℃, which determines the color-changing threshold of this layer to be 49±1℃.

[0033] Printing process: 300 mesh screen printing, printing speed 2m / min, drying temperature 60℃, drying time 30s, to ensure that the ink layer surface is flat and free of bubbles.

[0034] Preparation of RFID functional layer

[0035] Antenna fabrication: using silver paste ink (volume resistivity ≤ 5 × 10⁻) 5 Antenna patterns (Ω・cm) are created on PET substrates using gravure printing, with a line width of 0.3mm, a line thickness of 5μm, and a printing accuracy error of ≤±0.05mm.

[0036] Resistor integration: A temperature-sensitive resistor element (made of nickel-chromium alloy) is integrated at the end of the antenna using a printing process. The resistance value changes with temperature at a rate of 2500ppm / ℃, which can accurately sense fluctuations in ambient temperature.

[0037] Chip bonding: UHF RFID chips (operating frequency 860-960MHz) are selected and bonded to the antenna pads using conductive adhesive (conductive particle diameter 5μm). The bonding pressure is 0.2MPa and the bonding temperature is 80℃ to ensure reliable conductive connection between the chip and the antenna.

[0038] III. Assembly and Performance Testing

[0039] Assembly process: First, the RFID functional layer and the temperature-sensitive ink layer are bonded together with water-based adhesive (bonding pressure 0.1MPa, temperature 40℃). Then, the bonded functional layer is bonded together with the adhesive layer and the release paper backing paper in sequence to form a complete label.

[0040] Performance test results

[0041] Temperature response: When the ambient temperature reaches 49℃, the temperature-sensitive ink layer changes from colorless to blue (color intensity ≥80%) within 3 seconds, and returns to colorless within 30 seconds after the temperature drops below 49℃. The number of reversible color change cycles is ≥500.

[0042] RFID Function: Within a 1.5m range of the reader, the RFID chip can record temperature data through a resistive element (sampling interval 10s). When the temperature is ≥49℃, the chip triggers the alarm tag bit. After scanning by the reader, the alarm information can be uploaded to the cloud. The alarm response delay is ≤1s.

[0043] Structural reliability: After 500 friction tests (500g load, cotton cloth friction), the temperature-sensitive ink layer did not peel off; after a thermal cycling test from -20℃ to 60℃ (100 times), the electronic components of the RFID functional layer were undamaged and communication was normal.

[0044] This embodiment achieves the collaborative work of the temperature-sensitive ink layer and the RFID functional layer through clearly defined material parameters and process steps. It not only meets the requirements for intuitive temperature indication but also has automated data monitoring capabilities, and the overall cost is controlled within 0.5 yuan / piece, making it fully adaptable to single-use packaging scenarios such as logistics and warehousing.

[0045] Example 2:

[0046] The tag body has a multi-layered collaborative structure, consisting of a temperature-sensitive ink layer, an RFID functional layer, an adhesive layer, and a release paper backing layer, arranged from top to bottom. Each layer is designed to complement each other's functions and enhance performance.

[0047] Temperature-sensitive ink layer: Utilizing a composite film structure of "substrate + ink + abrasion-resistant protective layer"—the bottom layer is a 12μm thick PET carrier film 8 (enhancing overall stiffness), the middle layer is a 6-10μm thick temperature-sensitive ink 7 (containing reversible thermochromic microcapsules), and the surface is covered with a 3μm thick transparent polyurethane abrasion-resistant coating 6. The abrasion-resistant coating features a micro-bump texture design (bump diameter 50μm, height 2μm), which neither obstructs color development nor hinders observation, while reducing the surface friction coefficient to below 0.3, thus solving the problem of ink detachment due to friction in traditional temperature-sensitive labels. Its lower surface is bonded to the upper surface of the RFID functional layer via a water-based adhesive 5 (acrylate-based, 1-1.5μm thick). The adhesive layer uses a grid coating method (grid line width 0.1mm, spacing 2mm), ensuring bonding strength (≥0.4N / cm) while minimizing the adhesive layer's obstruction of the temperature-sensitive ink's color development.

[0048] RFID Functional Layer: Using a 25-35μm thick PET film as the PET substrate 9, it integrates a dual protection structure of "insulation isolation + signal shielding"—the area on the upper surface of the substrate that carries electronic components is first coated with a 0.5-1μm epoxy resin insulating coating 10 (moisture resistance ≥90% RH / 48h without leakage). A 0.3mm wide aluminum foil shielding ring 12 (made by vacuum evaporation process) is set around the electronic components 11. The distance between the shielding ring and the antenna is 0.5mm, which can reduce external electromagnetic interference (making the communication bit error rate ≤0.1%). The lower surface of the substrate is roughened (surface roughness Ra=0.8μm) to improve the adhesion to the adhesive layer (peel strength ≥0.5N / cm).

[0049] Adhesive layer 3: An acrylic pressure-sensitive adhesive with a gradient viscosity design, 15-25μm thick, divided from top to bottom into a high-viscosity zone (for bonding with the RFID functional layer, viscosity ≥30000mPa・s at 25℃) and an adjustable-viscosity zone (for bonding with release paper, viscosity adaptively adjusted with ambient temperature: viscosity ≥20000mPa・s at 0-10℃, viscosity 15000-20000mPa・s at 10-35℃). This ensures permanent bonding with the RFID functional layer and stable adhesion to packaging surfaces at different temperatures (compatible with various packaging materials such as paper, plastic, and metal).

[0050] Release paper backing 4: 80-120g / m² glassine paper is selected, and the surface is treated with double-sided silicone release (front release force 30-50g / inch, back release force ≥100g / inch). Easy-tear lines (micro-perforations spaced 5mm apart) are set on the front, which can be easily peeled off by gently tearing with your fingers, solving the problem of difficult peeling of traditional label release paper.

[0051] (1) Synergistic structure of temperature-sensitive ink layer and RFID functional layer:

[0052] The color-developing area of ​​the temperature-sensitive ink layer corresponds vertically to the position of the resistive element in the RFID functional layer (deviation ≤ 0.5 mm). Through the consistent thermal conductivity of the PET substrate (thermal conductivity 0.16-0.18 W / (m・K)), the temperature conduction error is ensured to be ≤ ±0.3℃, achieving synchronous response of "ink color development - resistance change" (response time difference ≤ 0.5 s). Simultaneously, the PET carrier film of the temperature-sensitive ink layer and the PET substrate of the RFID functional layer are made of the same material to avoid differences in thermal expansion coefficients (controlled within ±5×10⁻). 6 Interlayer warping caused by temperatures within / ℃.

[0053] (2) Antenna-chip integrated structure of RFID functional layer:

[0054] The antenna is manufactured using a twill printing process with silver paste ink (containing 3% silver nanowires). The linewidth is 0.2-0.4mm and the line thickness is 4-6μm. An "Ω"-shaped buffer structure (0.1mm radius of curvature) is incorporated at the antenna end to reduce stress concentration during bending (resistance change ≤5% after 100 180° bends). The temperature-sensitive resistor element (nickel-chromium alloy) is integrated into the antenna feed point using an embedded design (2μm embedding depth), forming a conductive path with the conductive adhesive bonding area of ​​the chip (0.8mm diameter), ensuring that the resistance signal transmission loss is ≤3%.

[0055] (3) Creativity enhancement brought about by structural optimization

[0056] Addressing common shortcomings of traditional tags: Through structural designs such as wear-resistant protective layers, shielding rings, and gradient adhesives, the problems of poor wear resistance of traditional temperature-sensitive tags, weak anti-interference of RFID tags, and insufficient compatibility of universal adhesives are overcome, achieving "solving multiple technical problems with a single structure".

[0057] Enhanced interlayer synergy: Through material matching, positional correspondence, and buffer structure design, the multi-layer structure is upgraded from simple stacking to a functionally synergistic whole. For example, the performance of temperature sensing-electronic synchronous response and antenna bending resistance are achieved through structural design rather than simple material selection, reflecting structural innovation.

[0058] Targeted design for different scenarios: Easy-tear lines and gradient adhesion are designed for the rapid handling needs of logistics packaging, while shielding rings and wear-resistant layers are adapted to the complex working conditions of warehousing environments. This significantly improves the practicality of the label in disposable packaging scenarios, forming a substantial difference from existing technologies.

[0059] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A temperature indicating smart label comprising a label body, characterized in that: The tag body has a multi-layer structure, which includes, from top to bottom, a temperature-sensitive ink layer, an RFID functional layer, an adhesive layer, and a release liner. The temperature-sensitive ink layer is a thin film structure, and its lower surface is tightly bonded to the upper surface of the RFID functional layer by a water-based adhesive. The RFID functional layer uses PET film as a substrate, and the area on the upper surface of the substrate that carries electronic components is provided with an insulating coating. The adhesive layer is a continuously coated uniform adhesive layer, one side of which is completely bonded to the lower surface of the RFID functional layer, and the other side is peelably connected to the release liner. The release liner is made of glassine paper with a strength of 80-120 g / m².

2. The temperature-sensing smart tag according to claim 1, characterized in that: The RFID functional layer includes a conductive ink antenna and an RFID chip; the antenna is made of conductive ink through printing technology, and a temperature-sensitive resistive element is integrated on the antenna layer; the RFID chip records temperature data through changes in the resistive element.

3. The temperature-sensing smart tag according to claim 1, characterized in that: The color change threshold of the temperature-sensitive ink layer is synchronized with the temperature alarm threshold of the RFID chip; when the temperature is greater than the set value, the ink layer changes color, and at the same time, the change in the resistance value of the RFID chip triggers the alarm tag bit.

4. A temperature-sensing intelligent tag according to claim 1, characterized in that: The temperature-sensitive ink layer is screen-printed onto the label film; the antenna of the RFID functional layer is a silver paste antenna and is attached with an RFID chip; the adhesive layer is an acrylic pressure-sensitive adhesive layer.

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