Mechanoluminescent film and application thereof

Abstract

The invention discloses a mechanoluminescent film and application thereof. The mechanoluminescent film is a technical material capable of visualizing damage of a material in a package in a transportation process, a PET polyester film is used as a basic material, the mechanoluminescent material and a polyurethane acrylate adhesive are mixed, and the mixture is uniformly coated on the material in the package, so that the mechanoluminescent film is obtained. The materials in the package can generate optical response when being subjected to vibration or external force, and then vibration damage can be visualized by detecting optical changes. The optical response degree of the surface of the material in the package also represents the degree of vibration or damage.

Description

Technical Field

[0001] The present invention belongs to the field of mechanoluminescent materials, and relates to a mechanoluminescent film and its application, in particular to a mechanoluminescent packaging film applied to packaging materials and having the function of self-detecting vibration damage. Background Art

[0002] With the rapid development of global logistics and supply chains, goods face complex mechanical environments during long-distance transportation and warehousing. Factors such as vibration, shock, temperature, and humidity changes may cause microscopic or macroscopic damage to the goods. Especially for fragile products, high-value products, or precision instruments, these damages may lead to irreparable losses, including but not limited to affecting the integrity and quality of fragile and high-value products, affecting the normal operation of precision instruments, and even posing safety hazards (such as chemical leakage or damaged lithium battery packaging).

[0003] Secondly, traditional damage detection methods often rely on external sensors or manual inspections, which are inefficient and easily affected by human factors. Currently, the mainstream packaging damage detection methods can be divided into destructive manual detection and external sensor integration solutions. These detection methods not only increase the detection cost and reduce the detection efficiency, but may even cause secondary damage.

[0004] Therefore, there is an urgent need to develop an efficient, real-time, and non-destructive self-detection solution. Summary of the Invention

[0005] The purpose of the present invention is to solve the defects of the prior art and provide a mechanoluminescent film and its application. The mechanoluminescent film of the present invention can be used as an inner packaging material with a "self-detection" function, that is, the material itself has the ability to detect its own damage, and the packaging damage can be detected by monitoring the optical changes of the composite material.

[0006] On the one hand, the present invention provides a mechanoluminescent film with a layered structure, including a substrate and a mechanoluminescent layer; the substrate and the mechanoluminescent layer are alternately stacked, and the number of substrates is greater than or equal to the number of mechanoluminescent layers;

[0007] The mechanoluminescent layer contains a mechanoluminescent material.

[0008] Preferably, the mechanoluminescent film has a bilayer structure, and the mechanoluminescent layer is coated on the surface of the substrate, or

[0009] The mechanoluminescent film has a trilayer structure, and the mechanoluminescent layer is sandwiched between two substrates.

[0010] Preferably, the mechanoluminescent layer is obtained by curing a mechanoluminescent resin solution;

[0011] The force-induced luminescence resin solution comprises the following materials in parts by weight: polyurethane acrylate thermosetting resin: 40-60 parts, methyl ethyl ketone: 0-10 parts, ethyl acetate: 5-25 parts, leveling agent: 0.2-0.4 part, dispersant: 0.1-0.6 part, force-induced luminescence material: 20-40 parts, ionic antistatic agent: 0.1-0.3 part.

[0012] Preferably, the force-induced luminescence material is ZnS:Mn powder; the particle size range of the ZnS:Mn powder is 2-6 μm, preferably 4-6 μm.

[0013] Preferably, the substrate is a PET film; the thickness of the PET film is 10-100 microns; the transparency of the PET film is more than 85%.

[0014] Preferably, the mixing method of the force-induced luminescence resin solution is as follows: first add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate and stir for 2 h until completely transparent; then sequentially add the leveling agent, dispersant, and ionic antistatic agent and stir evenly; finally add the force-induced luminescence material and disperse evenly to obtain the force-induced luminescence resin solution.

[0015] Preferably, the force-induced luminescence film is prepared by the following method:

[0016] Use the gravure coating method to evenly coat the force-induced luminescence resin solution on the surface of the PET film, and send the film into an oven equipment for drying or curing to obtain the force-induced luminescence film.

[0017] In some more preferred embodiments, the force-induced luminescence film is prepared by the following method:

[0018] Add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate to a magnetic stirrer, and stir at 1200 rpm for 2 hours until completely transparent;

[0019] Then sequentially add the leveling agent, dispersant, and ionic antistatic agent and stir for 30 minutes;

[0020] Finally, add the force-induced luminescence material in batches of 10 parts each time, and ultrasonically disperse at a power of 300 W for 15 minutes to obtain the force-induced luminescence resin solution;

[0021] Use a microgravure coater to coat the force-induced luminescence resin solution on a 12-μm-thick PET substrate, and control the wet film thickness to be 50 ± 5 μm;

[0022] First pre-bake the coated material at 80 °C for 3 minutes, and then post-cure at 120 °C for 8 minutes to finally obtain the force-induced luminescence film.

[0023] Preferably, the force-induced luminescence resin solution comprises the following materials in parts by weight:

[0024] 45 parts of polyurethane acrylate resin, 8 parts of methyl ethyl ketone, 15 parts of ethyl acetate, 0.3 part of BYK-333, 0.4 part of EFKA-4010, 32 parts of ZnS:Mn, 0.2 part of Larostat 519.

[0025] On the other hand, the present invention also provides an application of any one of the above-mentioned force-induced luminescence films in packaging materials.

[0026] The present invention mainly solves the problem that the vibration damage of the materials inside the package during transportation is invisible. The force-induced luminescence film of the present invention is a technical material that can visualize the damage of the materials inside the package during transportation. Based on the PET polyester film as the basic material, by mixing the force-induced luminescence material with polyurethane acrylate glue and uniformly coating it on the materials inside the package, the materials inside the package can produce an optical response when subjected to vibration or external force, and then the vibration damage can be visualized by detecting the optical change. The degree of optical response on the surface of the materials inside the package also represents the degree of vibration or damage.

[0027] The force-induced luminescence material of the present invention realizes the visualization of the damage of the materials inside the package. Through the degree of damage of the package, it can be judged whether there is damage to the object during transportation and the degree of damage, eliminating the steps and processes of disassembling the package, making the transportation inspection process more convenient, and also avoiding the damage and secondary damage to some delicate equipment during transportation and package disassembly. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of a double-layer force-induced luminescence film;

[0029] Figure 2 It is a schematic structural diagram of a triple-layer force-induced luminescence film;

[0030] Figure 3 It is a force-induced luminescence film sample prepared in Example 1;

[0031] Figure 4 It is the words written on the surface of the force-induced luminescence film sample prepared in Example 1 with a pen;

[0032] Figure 5 It is the instrument used in the test of Example 1;

[0033] Figure 6 It is the luminescence situation of the force-induced luminescence film prepared in Example 1 under different pressing forces. Detailed Embodiments

[0034] To further understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0035] The stress-luminescent film of the present invention is a layered film material, including a substrate and a stress-luminescent layer; the substrate and the stress-luminescent layer are alternately stacked, and the number of substrates is greater than or equal to the number of stress-luminescent layers; the stress-luminescent layer contains a stress-luminescent material.

[0036] A fluorescent material layer with stress-optical response (such as some fluorescent materials doped with metals) is coated on the substrate. When vibration or external force acts, the fluorescence intensity changes, and the state of the film is monitored in real time through a fluorescence detection system to identify damage.

[0037] In some preferred embodiments, the stress-luminescent film is composed of a substrate and a stress-luminescent layer coated on the surface of the substrate, and its structure is as Figure 1 shown, where the packaging material is the substrate and the stress-luminescent material glue layer is the stress-luminescent layer.

[0038] In some other preferred embodiments, the stress-luminescent layer is sandwiched between two substrates to form a sandwich-like layered structure, and its structure is as Figure 2 shown, where the packaging material is the substrate and the stress-luminescent material glue layer is the stress-luminescent layer.

[0039] In some embodiments, the substrate can be any one of the following packaging inner materials: PET, tear film, winding film, sealing tape, heat shrinkable film, plastic film, flexible packaging, aluminized film, iron core wire film, aluminum foil composite film, vacuum aluminized paper, composite film, composite paper, BOPP, etc.

[0040] The stress-luminescent layer is a coating that provides damage visualization function under the stimulation of external mechanical force.

[0041] In some embodiments, the stress-luminescent layer is obtained by curing and drying a solution or glue containing a stress-luminescent material.

[0042] In some preferred embodiments, the stress-luminescent layer is obtained by curing a stress-luminescent resin solution. The stress-luminescent resin solution includes the following materials in parts by weight: polyurethane acrylate thermosetting resin: 40-60 parts, methyl ethyl ketone: 0-10 parts, ethyl acetate: 5-25 parts, leveling agent: 0.2-0.4 parts, dispersant: 0.1-0.6 parts, stress-luminescent material (3-6um) 20-40 parts, ionic antistatic agent: 0.1-0.3 parts.

[0043] The mixing method of the stress-luminescent resin solution is:

[0044] First, add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate and stir for 2 h until completely transparent. Then, add a leveling agent, a dispersant, and an ionic antistatic agent in sequence and stir evenly; finally, add the mechanoluminescent material and disperse it evenly to obtain a mechanoluminescent resin solution.

[0045] The preparation method of the mechanoluminescent film is as follows:

[0046] Coat the mechanoluminescent resin solution evenly on the surface of the PET film by gravure coating, and send the film into an oven equipment for drying or curing. The curing temperature and time are adjusted according to the requirements of the resin type and the mechanoluminescent material.

[0047] The mechanoluminescent material is the core material used in the present invention to realize vibration damage monitoring. This material can respond to external forces (such as stretching, compression, or vibration) and change its optical properties (such as luminescence intensity, wavelength, etc.) under the action of force. When selecting a suitable mechanoluminescent material, the following requirements need to be met:

[0048] (1) High sensitivity: The material should respond to external forces (especially vibrations) sensitively enough to produce detectable optical changes under low-amplitude vibrations or stresses.

[0049] (2) Good stability: The material should have a long service life and stable optical properties, and avoid degradation during long-term use or exposure to harsh environments.

[0050] (3) High luminescence efficiency: The mechanoluminescent material should have a high luminescence efficiency to ensure that it can still produce obvious optical responses under low external light source irradiation.

[0051] (4) Compatibility: The selected material should be compatible with the materials inside the package and the resin matrix, and can be effectively combined with the polyester film substrate through appropriate coating or embedding methods.

[0052] The mechanoluminescent material is usually an inorganic mechanoluminescent material: such as ZnS system, rare earth ion-doped aluminates, silicates, calcium silicate system, etc.; the ZnS system includes ZnS:Mn, ZnS:Cu, etc., and CaZnOS / ZnS heterojunction.

[0053] These mechanoluminescent materials usually can exhibit relatively stable mechanoluminescence phenomena under the action of force. In some more preferred embodiments, the typical commercial mechanoluminescent powder ZnS:Mn is used as the mechanoluminescent material, and the particle size range of the material is about 2 - 6 μm. This material not only has excellent mechanoluminescence effects, good stability, and high-sensitivity response to force, but also has a good match with the colloid.

[0054] The materials inside the package need to meet the following requirements:

[0055] (1) Good mechanical properties: The material inside the package should have high strength, good stretchability and impact resistance, and is suitable for applications subject to vibration and external forces.

[0056] (2) Transparency: The material inside the package has high transparency, can effectively transmit optical signals, and is convenient for optical detection.

[0057] (3) Environmental resistance: The material inside the package has good chemical resistance, high temperature resistance and a long service life, and can maintain stable performance in harsh environments.

[0058] (4) Easy to process and form: The material inside the package is easy to process and can be effectively combined with the force-induced luminescence material through process methods such as film coating and coating.

[0059] In some more preferred embodiments, a polyester film (PET, polyethylene terephthalate) with high transparency, high strength, and easy processing and forming is selected as the material inside the package.

[0060] In some more specific preferred embodiments, the requirements for the transparent PET film material selected in the present invention are as follows:

[0061] The thickness of the PET film should be in the range of 10 - 100 microns, adjusted according to specific application requirements, to ensure that the optical response of the force-induced luminescence material can be fully exerted and the mechanical strength of the film is guaranteed;

[0062] The transparency of the PET material should reach more than 85%, to ensure that when performing optical signal detection, the optical signal is not overly obstructed;

[0063] The surface of the PET can be appropriately surface-treated (such as plasma treatment, coating aids, etc.) to enhance the adhesion and uniformity with the force-induced luminescence coating.

[0064] Resin is used to combine the force-induced luminescence material with the PET film substrate to form a uniform composite film. In some preferred embodiments, the selection of the resin material should be based on the following requirements:

[0065] (1) High adhesion: The resin should have good adhesion performance to ensure that the force-induced luminescence material and the polyester film can be firmly combined, and avoid peeling or detachment during use.

[0066] (2) Transparency: The transparency of the resin should match that of the PET film to avoid affecting the transmission of optical signals.

[0067] (3) Good durability: The resin should have high chemical stability, ultraviolet resistance and thermal stability to ensure that the film does not degrade during long-term use.

[0068] (4) Processability: The resin should be easy to coat and be able to form a uniform protective layer or binding layer on the surface of the force-induced luminescence material.

[0069] In some more specific preferred embodiments, the present invention selects a polyurethane acrylate adhesive, which has good adhesiveness and excellent mechanical properties and is suitable for binding with the force-induced luminescence material and the PET film.

[0070] The preparation of the force-induced luminescence coating needs to ensure the uniform dispersion of the force-induced luminescence material in the resin and be able to form a firm bond with the PET film. The preparation steps include:

[0071] (1) Dispersion of the force-induced luminescence material: First, mix the force-induced luminescence powder with an appropriate amount of resin solution and use ultrasonic waves or mechanical stirring for uniform dispersion. When necessary, use a dispersant or surfactant to improve the dispersibility.

[0072] (2) Optimization of the coating formula: According to the usage requirements of the film, adjust the ratio of the resin to the force-induced luminescence material to ensure that the coating has good optical and mechanical properties.

[0073] (3) Uniformly coat the prepared force-induced luminescence resin solution on the surface of the PET film. The coating process can use methods such as knife coating, spraying or spin coating to ensure a uniform coating.

[0074] (4) After coating, send the film into an oven equipment for drying or curing. The curing temperature and time are adjusted according to the requirements of the resin type and the force-induced luminescence material.

[0075] The performance of the force-induced luminescence layer prepared by the present invention is detected by the following methods:

[0076] (1) Optical performance test: Use equipment such as a fluorescence spectrometer to test the optical performance of the coating, including luminescence intensity, spectral response, etc.

[0077] (2) Mechanical performance test: Evaluate the adhesion and durability of the coating through tensile tests, hardness tests, etc.

[0078] Example 1

[0079] Weigh the following materials by mass parts: 45 parts of polyurethane acrylate resin, 8 parts of methyl ethyl ketone, 15 parts of ethyl acetate, 0.3 part of a leveling agent (BYK-333), 0.4 part of a dispersant (EFKA-4010), 32 parts of a force-induced luminescence material (ZnS:Mn, particle size 4-6 μm), and 0.2 part of an ionic antistatic agent (Larostat 519).

[0080] Add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate to a magnetic stirrer and stir at 1200 rpm for 2 hours until completely transparent. Sequentially add a leveling agent, a dispersant, and an ionic antistatic agent, and stir for 30 minutes. Finally, add the mechanoluminescent material in portions of 16 each time and perform ultrasonic dispersion for 15 minutes (power: 300 W) to obtain a mechanoluminescent resin solution. Use a microgravure coater to coat on a 12-μm PET substrate, and control the wet film thickness to be 50 ± 5 μm. Cure the coated material in segments, first pre-bake at 80°C for 3 minutes, and then perform main curing at 120°C for 8 minutes to finally obtain a mechanoluminescent film.

[0081] Example 2

[0082] Weigh the following materials by mass parts: 40 parts of polyurethane acrylate resin, 3 parts of methyl ethyl ketone, 5 parts of ethyl acetate, 0.3 part of leveling agent (BYK-333), 0.4 part of dispersant (EFKA-4010), 20 parts of mechanoluminescent material (ZnS:Mn, particle size 4 - 6 μm), and 0.2 part of ionic antistatic agent (Larostat 519).

[0083] Add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate to a magnetic stirrer and stir at 1200 rpm for 2 hours until completely transparent. Sequentially add a leveling agent, a dispersant, and an ionic antistatic agent, and stir for 30 minutes. Finally, add the mechanoluminescent material in portions of 10 each time and perform ultrasonic dispersion for 15 minutes (power: 300 W) to obtain a mechanoluminescent resin solution. Use a microgravure coater to coat on a 12-μm PET substrate, and control the wet film thickness to be 50 ± 5 μm. Cure the coated material in segments, first pre-bake at 80°C for 3 minutes, and then perform main curing at 120°C for 8 minutes to finally obtain a mechanoluminescent film.

[0084] Example 3

[0085] Weigh the following materials by mass parts: 60 parts of polyurethane acrylate resin, 0 part of methyl ethyl ketone, 25 parts of ethyl acetate, 0.3 part of leveling agent (BYK-333), 0.4 part of dispersant (EFKA-4010), 20 parts of mechanoluminescent material (ZnS:Mn, particle size 4 - 6 μm), and 0.2 part of ionic antistatic agent (Larostat 519).

[0086] Add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate to a magnetic stirrer and stir at 1200 rpm for 2 hours until completely transparent. Add a leveling agent, a dispersant, and an ionic antistatic agent in sequence and stir for 30 minutes. Finally, add the force-induced luminescence material in portions of 10 each time and perform ultrasonic dispersion for 15 minutes (power 300 W) to obtain a force-induced luminescence resin solution. Use a gravure coater to coat on a 12-μm PET substrate, and control the wet film thickness to be 50 ± 5 μm. Cure the coated material in segments, first pre-bake at 80 °C for 3 minutes, and then perform main curing at 120 °C for 8 minutes to finally obtain a force-induced luminescence thin film.

[0087] Example 4

[0088] Weigh the following materials by mass parts: 45 parts of polyurethane acrylate resin, 10 parts of methyl ethyl ketone, 15 parts of ethyl acetate, 0.3 part of leveling agent (BYK-333), 0.4 part of dispersant (EFKA-4010), 40 parts of force-induced luminescence material (ZnS:Mn, particle size 4-6 μm), and 0.2 part of ionic antistatic agent (Larostat 519).

[0089] Add polyurethane acrylate resin, methyl ethyl ketone, and ethyl acetate to a magnetic stirrer and stir at 1200 rpm for 2 hours until completely transparent. Add a leveling agent, a dispersant, and an ionic antistatic agent in sequence and stir for 30 minutes. Finally, add the force-induced luminescence material in portions of 20 each time and perform ultrasonic dispersion for 15 minutes (power 300 W) to obtain a force-induced luminescence resin solution. Use a gravure coater to coat on a 12-μm PET substrate, and control the wet film thickness to be 50 ± 5 μm. Cure the coated material in segments, first pre-bake at 80 °C for 3 minutes, and then perform main curing at 120 °C for 8 minutes to finally obtain a force-induced luminescence thin film.

[0090] The force-induced luminescence thin films prepared in Examples 1-4 have excellent force-induced luminescence performance. Taking Example 1 as an example, under dark conditions, write the letter "ML" on the thin film prepared in Example 1 (the thin film sample prepared in Example 1 is as Figure 3 shown), and the effect is as Figure 4 shown, and the word "ML" with a bright luminescence effect can be observed.

[0091] The inventor tested the force-induced luminescence thin films prepared in Examples 1-4. The test was carried out using a fluorescence spectrometer connected to a PMT photon counter (as Figure 5 shown), and the luminescence intensity of the force-induced luminescence thin films prepared in each example was measured under different pressing forces. The test results of Example 1 are as Figure 6 shown. As the pressing force gradually increases (2.5 N to 30.0 N), the luminescence intensity of the force-induced luminescence thin film gradually increases, showing a good linear response relationship, indicating the high sensitivity of the thin film to force. The test results of other examples are similar to those of Example 1.

[0092] The above are only preferred examples of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included within the protection scope of the present invention.

Claims

1. A mechanoluminescent film, characterized in that: A layered structure is adopted, including a substrate and a mesoluminescent layer; the substrate and the mesoluminescent layer are alternately stacked, and the number of substrates is greater than or equal to the number of mesoluminescent layers; The mechanoluminescent layer comprises a mechanoluminescent material.

2. The mechanoluminescent film according to claim 1, characterized in that: The mechanoluminescent film is a double-layer structure, in which the mechanoluminescent layer is coated on the surface of a substrate, or the mechanoluminescent film is a three-layer structure, in which the mechanoluminescent layer is sandwiched between two layers of substrate.

3. The mechanoluminescent film according to claim 1 or 2, characterized in that: The mechanoluminescent layer is obtained by curing a mechanoluminescent resin solution; The force-induced luminescent resin solution includes the following materials in parts by weight: 40 to 60 parts of polyurethane acrylic thermosetting resin, 0 to 10 parts of butanone, 5 to 25 parts of ethyl acetate, 0.2 to 0.4 parts of leveling agent, 0.1 to 0.6 parts of dispersant, 20 to 40 parts of force-induced luminescent material, and 0.1 to 0.3 parts of ionic antistatic agent.

4. The mechanoluminescent film according to claim 3, characterized in that: The mechanoluminescent material is ZnS:Mn powder; the particle size of the ZnS:Mn powder is in the range of 2 to 6 μm, preferably 4 to 6 μm.

5. The mechanoluminescent film according to claim 4, characterized in that: The substrate is a PET film; the thickness of the PET film is 10-100 microns; and the transparency of the PET film is above 85%.

6. The mechanoluminescent film according to claim 5, characterized in that: The mixing method of the force-induced luminescent resin solution is: firstly add polyurethane acrylic resin, butanone and ethyl acetate and stir for 2 hours until completely transparent; then add leveling agent, dispersant and ionic antistatic agent in sequence and stir evenly; finally add force-induced luminescent material and disperse evenly to obtain the force-induced luminescent resin solution.

7. The mechanoluminescent film according to claim 6, characterized in that: Prepared by the following method: The mechanoluminescent resin solution is coated on the surface of the PET film by gravure coating, and the film is sent to an oven for drying or curing to obtain the mechanoluminescent film.

8. The mechanoluminescent film according to claim 7, characterized in that: Prepared by the following method: Add polyurethane acrylic resin, butanone and ethyl acetate into a magnetic stirrer and stir at 1200 rpm for 2 hours until completely transparent; Then add leveling agent, dispersant, and ionic antistatic agent in sequence and stir for 30 minutes; Finally, the mechanoluminescent material was added in batches of 10 portions each time, and ultrasonically dispersed at a power of 300 W for 15 minutes to obtain a mechanoluminescent resin solution; A micro-gravure coater was used to coat the mesoluminescent resin solution on a 12 μm thick PET substrate, and the wet film thickness was controlled at 50 ± 5 μm; The coated material was pre-baked at 80° C. for 3 minutes and then cured at 120° C. for 8 minutes to finally obtain the mesoluminescent film.

9. The mechanoluminescent film according to claim 7, characterized in that: The power-induced luminescent resin solution comprises the following materials in parts by weight: 45 parts of polyurethane acrylic resin, 8 parts of butanone, 15 parts of ethyl acetate, 0.3 parts of BYK-333, 0.4 parts of EFKA-4010, 32 parts of ZnS:Mn, and 0.2 parts of Larostat 519.

10. Use of the mechanoluminescent film according to any one of claims 1 to 9 in packaging materials.

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