Anti-counterfeiting rubber cap based on micro-nano optical structure and preparation method thereof

Abstract

The invention relates to the technical field of anti-counterfeiting, and discloses an anti-counterfeiting rubber cap based on a micro-nano optical structure and a preparation method thereof.The anti-counterfeiting rubber cap comprises an anti-counterfeiting rubber cap body, a plurality of bright lines are arranged on the outer side of the anti-counterfeiting rubber cap body, dark lines are arranged on the anti-counterfeiting rubber cap body located between every two adjacent bright lines, and a code spraying area is further arranged on the outer side of the anti-counterfeiting rubber cap body; a plurality of separation lines are arranged at the top of the anti-fake rubber cap, an anti-fake chip is fixedly connected to the center of the top of the anti-fake rubber cap, and a plurality of verification points are arranged at the positions, close to the separation lines, of the top of the anti-fake rubber cap. Multiple anti-counterfeiting structures such as bright fringes, dark fringes, a code spraying area and an anti-counterfeiting chip are integrated, a multi-dimensional anti-counterfeiting system is formed, the imitation difficulty is greatly improved, a multi-layer interference optical variable structure of the bright fringes presents specific color value changes along with the visual angle, and the identification degree is high; due to the design of the micro-nano grating with dark fringes, exclusive patterns with high diffraction efficiency can be generated through laser irradiation, and the anti-counterfeiting reliability is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of anti-counterfeiting technology, in particular to an anti-counterfeiting cap based on micro-nano optical structure and a preparation method thereof. BACKGROUND

[0002] The anti-counterfeiting cap is an anti-counterfeiting mark used for packaging and sealing, which is usually made of plastic, aluminum-plastic composite and other materials, has the functions of sealing and anti-counterfeiting, and is widely used for the bottle mouth packaging of high-end or easily counterfeited products such as wine, cosmetics and medicine.

[0003] The anti-counterfeiting caps on the current market generally rely on single printed patterns or simple code spraying. These marks lack technical barriers and can be easily copied by criminals through high-definition scanning and counterfeit printing, resulting in a flood of counterfeit and inferior products. Although some existing anti-counterfeiting caps introduce photochromic ink or two-dimensional code technology, the photochromic effect is mostly basic color change, lacks micro-nano scale structure design, has low recognition and low imitation cost, and the two-dimensional code is easy to fail due to wear and tear and pollution, and has limited data storage capacity, making it difficult to realize full life cycle tracking. In addition, the anti-counterfeiting information of traditional caps is mostly limited to the visual level, lacking chip-level information interaction capability, and consumers cannot verify the authenticity through a convenient way. SUMMARY

[0004] The present application aims to provide an anti-counterfeiting cap based on micro-nano optical structure and a preparation method thereof, which integrates multi-dimensional anti-counterfeiting technology, has high recognition and high imitation difficulty, and has stable and controllable production process, thereby effectively solving the problems in the background art.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] The anti-counterfeiting cap based on micro-nano optical structure comprises an anti-counterfeiting cap, a plurality of bright lines are arranged on the outer side of the anti-counterfeiting cap, a dark line is arranged between adjacent two bright lines, a code spraying area is further arranged on the outer side of the anti-counterfeiting cap, a plurality of separation lines are arranged on the top of the anti-counterfeiting cap, an anti-counterfeiting chip is fixedly connected to the center position of the top of the anti-counterfeiting cap, and a plurality of check points are arranged on the top of the anti-counterfeiting cap close to the separation lines.

[0007] As a further preferred scheme of the present application, the bright lines are stacked by a plurality of layers of interference type photochromic pigment transparent films.

[0008] As a further preferred scheme of the present application, the dark line is an infrared light sensitive pigment.

[0009] As a further preferred scheme of the present application, the code printing area position is sprayed with a chemical sensitive material and a hydrophilic color-changing material, the chemical sensitive material is sensitive to commonly used organic solvents such as acetone for code printing removal, and when the code is removed by wiping with such solvents, the material will irreversibly change color within a few seconds, and the hydrophilic color-changing material is sensitive to liquids, and after contacting tap water, edible oil, ethanol, etc., it will change color within a few seconds, water will show pink, oil will show brown, and ethanol will show blue, which can directly show whether the code has been tampered with and whether it has been in contact with liquid, providing double protection against illegal removal or tampering of the code and enhancing the security of the security cap.

[0010] As a further preferred scheme of the present application, the anti-fake chip is an ultra-high frequency rfid chip, after the instrument is close to the anti-fake chip, the encrypted ID is automatically read and decrypted, then a remote background server is connected through 4G / 5G or WiFi, the server verifies the legality of the ID, then randomly selects multiple check points from the complete check point position matrix corresponding to the anti-fake cap, generates a position diagram without all points, and issues it to the instrument terminal, the instrument display terminal presents a schematic diagram containing a separation line contour and the selected check point markers, the operator compares the check points on the top of the actual anti-fake cap with the schematic diagram, if the check points marked in the schematic diagram completely correspond to the actual positions, it is determined to be a genuine product, otherwise it is a counterfeit product.

[0011] The preparation method of the anti-fake cap based on micro-nano optical structure comprises the following steps:

[0012] S1, material preparation, base material processing, low density polyethylene particles are selected, the melt flow rate (190℃ / 2.16kg) is controlled at 2.0-3.0g / 10min, the density is 0.920-0.925g / cm³, and then the impurities are removed by a vibrating screen (100 mesh), and then put into a hot air circulating drying box, dried at 80℃ for 4 hours, turned over every hour during the period, and ensured that the moisture content was reduced to below 0.05%, the dried particles were packed in a sealed bag, labeled with batch and drying time, and ready for use.

[0013] S1.1, clear line material modulation, interference type optical variable pigment is selected, titanium dioxide-silicon dioxide composite particles with a particle size distribution of 12-18μm, a titanium dioxide layer thickness of 20-30nm, and a silicon dioxide layer thickness of 30-40nm, are mixed with acrylic resin (hydroxyl content 3%) at a mass ratio of 1:3, poured into a planetary stirring tank, and the stirring parameters are set as revolution 280r / min and rotation 750r / min, stirring in an environment of 23-25℃ for 50 minutes, stopping 3 times in the middle to clean the tank wall with a scraper, ensuring no agglomerated particles, after modulation, filtered with 400 mesh nylon filter cloth, packed in a brown glass bottle, sealed and stored in an environment below 20℃.

[0014] S1.2, dark pattern material preparation, micro-nano structure carrier is selected as polymethyl methacrylate particles with a molecular weight of 300-350 million and a light transmittance of greater than or equal to 92%, an electron beam lithography system (acceleration voltage 100kv) is used to engrave micro-nano gratings on the surface of a silicon-based mold, the period is 350-450nm, the depth is 60-80nm, the pattern includes a brand logo (line width 2μm) and a diffraction fringe (interval 500nm), after lithography, the structure is deepened by reactive ion etching (etching gas cf4, flow rate 20sccm).

[0015] S2, auxiliary material preparation and inspection, obtain matte silver gray uv ink, epoxy resin, rfid chip,

[0016] The matte silver gray uv ink is tested for viscosity (3200±200mpa・s at 25℃), a 100μm wet film is prepared using a coater, after uv curing (365nm, 600mj / cm²), the adhesion (crosshatch method 5b) and scratch resistance (no scratches under 750g force) are detected;

[0017] The epoxy resin is tested for gel time (40-50min at 80℃), after curing, the hardness (shored85±2) and light transmittance (400-800nm waveband greater than or equal to 91%) are tested;

[0018] 50 pieces of rfid chip are randomly selected from each batch, the reading distance (6-9cm), data storage time (greater than or equal to 10 years), and id uniqueness (no repeated codes) are tested.

[0019] S3, injection molding step, the a hopper of the injection molding equipment is polyethylene particles, and the b hopper is polymethyl methacrylate particles.

[0020] S3.1, base layer polyethylene injection, a closed-loop controlled servo injection system is used, first, the front end of the barrel is emptied at a pre-injection speed of 5mm / s, then the formal injection is started, the injection is carried out to the base layer area, when the cavity volume is 85%, the speed is increased in three stages, the injection stage process is as follows:

[0021] First speed 30mm / s (filling 30% cavity), corresponding to the main flow channel to the cavity inlet section of the mold, pressure 90mpa±2mpa, the front is ensured to advance smoothly by the melt flow sensor;

[0022] Second speed 50mm / s (filling to 60% cavity), when the melt front reaches 5mm from the edge of the dark pattern area, the speed is increased by the infrared detector, the pressure is simultaneously increased to 95mpa to avoid insufficient base layer formation;

[0023] Three speed 20mm / s (buffer before pressure), cavity filling to 85%, the pressure dropped to 80mpa, through the mold displacement sensor (accuracy ± 0.01mm) to confirm the base layer preform contour, for the subsequent polymethyl methacrylate injection reserved accurate space;

[0024] When injection molding, a rectangular code spraying area of 15mm×5mm is reserved on the side of the anti-fake rubber cap 91.

[0025] S3.2, dark line polymethyl methacrylate injection, after the injection of polyethylene base layer is completed, interval 0.8 seconds, that is, ensure that the polyethylene base layer is initially shaped, low-speed precision injection is started, and the injection process is as follows:

[0026] Initial 10mm / s (fill 5% cavity), through the micro flow valve control, make the polymethyl methacrylate melt slowly flow into the dark area, avoid the interface mixing caused by impact base layer;

[0027] Then rise to 25mm / s (fill the remaining 10% cavity), the pressure is kept at 100mpa±2mpa, the mold pressure sensor real-time monitoring dark area pressure, reach 95mpa when trigger pressure preparation signal, ensure that the micro-nano structure is completely filled.

[0028] S3.3, demolding, mechanical hand takes the piece, visual inspection has no lack of material, flash, qualified parts are put into the transfer tray.

[0029] S3.4, post-processing, unqualified parts are marked and stored separately, qualified parts are sent to the laser trimming machine, and the edge is trimmed along the parting line. After trimming, the workpiece enters the ultrasonic cleaning line for cleaning.

[0030] S4, making clear lines, the anti-fake rubber cap is fixed on the pneumatic workbench, the reference edge is identified by ccd vision system, the clear line area is treated by plasma treatment machine for 2.5 seconds, and the surface energy is ≥40mn / m after treatment, which ensures good ink adhesion.

[0031] S4.1, screen printing, select 350 mesh stainless steel screen, detect four sides with tension meter, deviation ≤1n / cm, after printing, the workpiece is placed for 15 seconds, and then enters the uv curing oven.

[0032] S4.2, curing and protective layer, uv curing oven is irradiated in three sections: pre-curing (100mw / cm², 1s), main curing (300mw / cm², 2s), and post-curing (200mw / cm², 1s), total energy 800mj / cm², conveying belt speed 1.2m / min, after curing, the clear line area is detected by gloss meter at 60° angle, gloss ≥90gu, then the anti-fake rubber cap is installed on the self-rotating jig, the vacuum chamber is pumped to 5×10⁻ 4After the PA, heat the PC evaporation boat to 290℃, evaporation rate of 4-6nm / s, film thickness control 5±0.3μm, real-time adjustment by quartz crystal monitor.

[0033] S5, code area production, select the same low density polyethylene with the main body of the cap, additional preparation of surface treatment agent, containing silane coupling agent kh-550, concentration 3%, used to enhance the adhesion of the code area and the color changing layer, the treatment agent needs to be filtered through 0.2μm filter membrane, to ensure that there is no impurities;

[0034] The color changing layer material is mixed with chemical sensitive material and hydrophilic color changing material in a mass ratio of 1:1 to form a color changing layer pigment. The chemical sensitive material is bromocresol green (purity ≥98%), and the hydrophilic color changing material is anhydrous cobalt chloride. Both are ground to a particle size of ≤5μm and mixed with acrylic resin (solid content 45%);

[0035] The isolation layer material is polyvinyl alcohol, which is prepared into an 8% aqueous solution and 0.1% defoaming agent (silicone) is added. It is stirred magnetically for 30 minutes until it is completely dissolved.

[0036] The color changing layer and the isolation layer are coated. The color changing layer material is uniformly coated on the pretreated code area using a precision doctor blade coater. After coating, it immediately enters a hot air oven for drying at 50℃ for 10 minutes to form a dry film. If alcohol-soluble inkjet ink is used, an isolation layer needs to be covered on the surface of the color changing layer. The pva solution is printed on the code area using inkjet printing. The printing range is 0.5mm larger than the color changing layer to ensure complete coverage.

[0037] S6, separation line printing, using 200 mesh polyester screen, printing pattern is radial line, line width 2.0±0.05mm, before printing, wipe the screen with alcohol to ensure no residual ink, doctor blade pressure 0.25mpa, speed 30mm / s, after printing, cure under uv lamp for 3 seconds, after curing, check the edge of the line with a microscope (100 times), jaggedness ≤0.02mm.

[0038] S7, check point forming, vacuum adsorption fixed anti-fake cap, visual identification of separation line, calibration of x / y axis deviation, while the micro point glue valve injects uv ink in the mold cavity, the downward speed of the printing equipment mold is 4mm / s, after contacting the top of the anti-fake cap, it keeps pressure at 12mpa, while the uv lamp irradiates for 4 seconds.

[0039] S8, chip packaging, the anti-fake cap is fixed on the jig, and a groove is processed on the top of the anti-fake cap in the machining center. Conductive silver glue is applied at the bottom of the groove. The rfid chip is sucked by the mechanical hand and placed in the center of the groove. A pressure of 0.8n is applied for 8 seconds. Then, the anti-fake cap is baked in a 40℃ oven for 30 minutes. Finally, the rfid chip is coated with epoxy resin using a dispensing machine, covering the chip and the edge by 0.2mm, and cured at 80℃ for 90 minutes.

[0040] S9.1, optical performance detection, bright line: multi-angle spectrophotometer measures 0°, 45°, 90° color value, 0° l*=45±2, a*=50±2, b*=10±2;

[0041] 45° l*=40±2, a*=-10±2, b*=60±2;

[0042] 90° l*=35±2, a*=20±2, b*=-40±2, color difference value δe≤2;

[0043] Dark line: 532nm laser vertical irradiation, spectrometer detects first-order diffraction efficiency≥32%, diffraction pattern is collected by ccd camera, and the coincidence degree is≥96% compared with the standard template.

[0044] S9.2, check point: randomly select 20 points, three coordinate measurement position deviation, maximum value≤0.25mm, height consistency≤0.03mm;

[0045] RFID chip: RFID card reader reads 10 times at a distance of 8cm, success rate is 100%, data transmission time≤0.5s, encrypted id matches with database;

[0046] Mechanical properties: the bright line area is pasted with 3m tape (model 610) and quickly torn off, no ink falling off;

[0047] Code detection area, chemical response: wipe the code area with acetone (analytical pure), the color change rate is≥95% within 30s, and the color change is irreversible (no recovery after 24h);

[0048] Liquid response: respectively drop tap water, edible oil and ethanol, all should show color within 10s (water→pink, oil→brown, ethanol→blue), and the coloration area is≥90%.

[0049] S10, packaging, adopt anti-static bag as inner packaging, and put into silica gel desiccant, and outer packaging adopts corrugated carton.

[0050] Compared with the prior art, the present application has the following beneficial effects:

[0051] In the present application, multiple anti-counterfeiting structures such as bright line, dark line, code area and anti-counterfeiting chip are integrated to form a multi-dimensional anti-counterfeiting system, which greatly improves the difficulty of imitation, the multilayer interference optical variable structure of bright line presents specific color value change with viewing angle, and the recognition degree is high; the micro-nano grating design of dark line can produce exclusive pattern with high diffraction efficiency under laser irradiation, and the anti-counterfeiting reliability is enhanced;

[0052] The chemical sensitive and hydrophilic color-changing material in the code spraying area can produce specific color development reactions by contacting different substances, preventing the code from being removed by chemical methods in the later stage, the RFID chip realizes information storage and traceability, and the check points and the separation lines improve the structural stability and identification accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 It is a schematic diagram of the main structure of the application.

[0054] In the figure: 1, anti-fake rubber cap; 2, bright lines; 3, dark lines; 4, code spraying area; 5, separation line; 6, anti-fake chip; 7, check point. DETAILED DESCRIPTION

[0055] In order to make the technical means, creative features, purposes and effects of the application easy to understand, the application will be further described below in combination with specific embodiments.

[0056] As shown in Figure 1 The anti-fake rubber cap based on micro-nano optical structure provided by the application comprises an anti-fake rubber cap 1, a plurality of bright lines 2 are arranged on the outer side of the anti-fake rubber cap 1, a dark line 3 is arranged on the anti-fake rubber cap 1 between adjacent two bright lines 2, a code spraying area 4 is further arranged on the outer side of the anti-fake rubber cap 1, a plurality of separation lines 5 are arranged on the top of the anti-fake rubber cap 1, an anti-fake chip 6 is fixedly connected to the center position of the top of the anti-fake rubber cap 1, and a plurality of check points 7 are arranged on the top of the anti-fake rubber cap 1 close to the separation lines 5.

[0057] The bright lines 2 are stacked by a plurality of layers of interference type light-changing pigment transparent films, the dark line 3 is an infrared light sensitive pigment, the code spraying area 4 is sprayed with chemical sensitive material and hydrophilic color-changing material, the chemical sensitive material is sensitive to common organic solvents such as acetone used for removing the code, when the code is removed by wiping with such a solvent, the material will irreversibly change color within a few seconds, the hydrophilic color-changing material is sensitive to liquid, and will present corresponding color changes within a few seconds after contacting tap water, edible oil and ethanol, the water will show pink, the oil will show brown, and the ethanol will show blue, which can directly show whether the code is tampered with and whether it has been contacted with liquid, double protection is provided to prevent the code from being illegally removed or tampered with, and the safety of the anti-fake rubber cap 1 is enhanced.

[0058] The anti-counterfeiting chip 6 is an ultra-high frequency rfid chip. After the instrument is close to the anti-counterfeiting chip 6, the encrypted ID is automatically read and decrypted, and then a remote background server is connected through 4G / 5G or WiFi. After the server verifies the legality of the ID, a plurality of check points 7 are randomly extracted from the complete check point 7 position matrix corresponding to the anti-counterfeiting cap 1, a position diagram without all points is generated, and the position diagram is sent to the instrument terminal. The instrument display terminal presents a schematic diagram containing the outline of the separation line 5 and the mark of the extracted check point 7. The operator compares the check point 7 on the top of the actual anti-counterfeiting cap 1 with the schematic diagram. If the check point 7 marked in the schematic diagram completely corresponds to the actual position, it is determined to be a genuine product. If it does not correspond at any place, it is a counterfeit product.

[0059] The preparation method of the anti-counterfeiting cap based on the micro-nano optical structure comprises the following steps:

[0060] S1, material preparation, base material treatment, low-density polyethylene particles are selected, the melt flow rate (190℃ / 2.16kg) is controlled at 2.0-3.0g / 10min, the density is 0.920-0.925g / cm³, and then the impurities are removed by a vibrating screen (100 mesh) and then placed in a hot air circulating drying box, dried at 80℃ for 4 hours, turned over once every hour during the period, and ensured that the water content is reduced to below 0.05%. The dried particles are placed in a sealed bag, labeled with batch number and drying time, and ready for use.

[0061] S1.1, clear line material modulation, interference type optical variable pigment selects flaky titanium dioxide-silicon dioxide composite particles with a particle size distribution of 12-18μm, a titanium dioxide layer thickness of 20-30nm, and a silicon dioxide layer thickness of 30-40nm, mixed with acrylic resin (hydroxyl content 3%) at a mass ratio of 1:3, poured into a planetary stirring tank, and the stirring parameters are set as revolution 280r / min and rotation 750r / min, stirring for 50 minutes in an environment of 23-25℃, stopping for 3 times in the middle to clean the tank wall with a scraper to ensure no agglomerated particles, after modulation, filtered with 400 mesh nylon filter cloth, placed in a brown glass bottle, sealed and stored in an environment below 20℃.

[0062] S1.2, dark line 3 material preparation, micro-nano structure carrier selects polymethyl methacrylate particles with a molecular weight of 300-350 thousand and a light transmittance of ≥92%, uses an electron beam lithography system (accelerating voltage 100kv) to engrave a micro-nano grating on the surface of a silicon-based mold, with a period of 350-450nm and a depth of 60-80nm, the pattern containing a brand logo (line width 2μm) and a diffraction fringe (interval 500nm), after lithography, the structure is deepened by reactive ion etching (etching gas cf4, flow rate 20sccm).

[0063] S2, auxiliary material preparation and inspection, obtain matte silver gray uv ink, epoxy resin, rfid chip 6,

[0064] Matte silver gray uv ink test viscosity (3200 ± 200 mpa · s at 25 °c), 100 μm wet film is prepared with coater, uv curing (365 nm, 600 mj / cm²) after, test adhesion (cross method 5b) and scratch resistance (750 g force without scratch);

[0065] Epoxy resin test gel time (40-50 min at 80 °c), test hardness (shored 85 ± 2) and light transmittance (400-800 nm band ≥91%) after curing;

[0066] Rfid chip randomly selected 50 pieces per batch, test reading distance (6-9 cm), data storage time (≥10 years), ensure id uniqueness (no repeat code).

[0067] S3, injection molding step, injection molding equipment a hopper is polyethylene particles, b hopper is polymethyl methacrylate particles.

[0068] S3.1, base layer polyethylene injection, servo injection system with closed loop control, first with 5 mm / s pre-injection speed emptying the front end of the cylinder air, then starting the formal injection, injection to the base layer area, the cavity volume 85% when, the speed is increased in three stages, its injection ladder process as follows:

[0069] Speed 30 mm / s (filling 30% cavity), corresponding to the mold main runner to the cavity inlet section, pressure 90 mpa ± 2 mpa, through the melt flow sensor to ensure the front smooth advance;

[0070] Speed 50 mm / s (filling to 60% cavity), when the melt front reaches the edge of 5 mm of dark line 3 region, triggered by infrared detector speed up, pressure is simultaneously increased to 95 mpa, to avoid the base layer forming deficiency;

[0071] Three speed 20 mm / s (pre-buffering), when the cavity filling to 85%, the pressure is reduced to 80 mpa, through the in-mold displacement sensor (accuracy ± 0.01 mm) to confirm the base layer preforming profile, to reserve accurate space for subsequent polymethyl methacrylate injection;

[0072] When injection molding, 15 mm × 5 mm rectangular code area is reserved on the side of the anti-fake cap 91.

[0073] S3.2, dark line 3 polymethyl methacrylate injection, when the polyethylene base layer injection is completed, interval 0.8 seconds, namely ensure that the polyethylene base layer starts after initial setting, using low speed precision injection, its injection process as follows:

[0074] Initial 10 mm / s (fill 5% cavity), through the micro flow valve control, so that the polymethyl methacrylate melt slowly flows into the dark 3 area, avoid the impact of the interface mixing caused by the base layer;

[0075] Then rise to 25 mm / s (fill the remaining 10% cavity), the pressure is kept at 100 mpa ± 2 mpa, the in-mold pressure sensor real-time monitoring dark 3 area pressure, reach 95 mpa when trigger pressure preparation signal, ensure the complete filling of micro-nano structure.

[0076] S3.3, demolding, mechanical hand takes the piece, visual inspection of the lack of material, flash, qualified parts into the transfer tray.

[0077] S3.4, post-processing, unqualified parts marked separately, qualified parts sent to laser trimming machine, trimming along the parting line, trimming after the workpiece into the ultrasonic cleaning line cleaning.

[0078] S4, the production of the clear line, the anti-fake glue cap is fixed on the pneumatic workbench, the reference edge is identified by ccd vision system, the clear 2 area is treated by plasma treatment machine for 2.5 seconds, and the surface energy is ≥40 mn / m after treatment, which ensures good ink adhesion.

[0079] S4.1, screen printing, select 350 mesh stainless steel screen, detect the four edges with tension meter, deviation ≤1 n / cm, after printing, the workpiece is placed for 15 seconds, and then enters the uv curing oven.

[0080] S4.2, curing and protective layer, uv curing oven is divided into three sections: pre-curing (100 mw / cm², 1 s), main curing (300 mw / cm², 2 s), and post-curing (200 mw / cm², 1 s), total energy 800 mj / cm², conveying belt speed 1.2 m / min, after curing, the gloss meter 60° angle detection, clear line area gloss ≥90 gu, then, the anti-fake glue cap is installed on the self-rotating jig, the vacuum chamber is pumped to 5×10⁻ 4 Pa, then heat the pc evaporation boat to 290℃, evaporation rate 4-6 nm / s, film thickness control 5±0.3 μm, real-time adjustment through quartz crystal monitor.

[0081] S5, code area production, select the same low density polyethylene as the glue cap body, prepare additional surface treatment agent, containing silane coupling agent kh-550, concentration 3%, used to enhance the adhesion between the code area and the color changing layer, the treatment agent needs to be filtered through 0.2 μm filter membrane to ensure no impurities;

[0082] Color-changing layer material, the color-changing layer pigment is mixed by the chemical sensitive material and the hydrophilic color-changing material in a mass ratio of 1:1, the chemical sensitive material is bromocresol green (purity ≥98%), the hydrophilic color-changing material is anhydrous cobalt chloride, both are ground to a particle size ≤5 μm, and mixed with acrylic resin (solid content 45%);

[0083] Isolation layer material, polyvinyl alcohol is used to prepare an 8% aqueous solution, 0.1% defoaming agent (silicone type) is added, and magnetic stirring is performed for 30 minutes until complete dissolution;

[0084] Color-changing layer and isolation layer coating, a precision knife coater is used to uniformly coat the color-changing layer material on the pre-processed code spraying area, and immediately after coating, the color-changing layer is dried in a hot air oven at 50°C for 10 minutes to form a dry film; if alcohol-soluble inkjet printing ink is used, an isolation layer is coated on the surface of the color-changing layer by printing the pva solution on the code spraying area in an inkjet printing manner, and the printing range is 0.5 mm larger than that of the color-changing layer to ensure complete coverage.

[0085] S6, separation line printing, a 200-mesh polyester screen is used to print a radial line pattern with a line width of 2.0±0.05 mm, the screen is wiped with alcohol before printing to ensure that there is no residual ink, the squeegee pressure is 0.25 mpa, and the speed is 30 mm / s; after printing, the line edges are checked under a microscope (100 times) after curing under a uv lamp for 3 seconds, and the jaggedness is ≤0.02 mm.

[0086] S7, verification point forming, the anti-fake glue cap is fixed by vacuum adsorption, the visual identification separation line 5 is calibrated for x / y axis deviation, the micro-point glue valve is used to inject uv ink into the mold cavity, the downward speed of the mold of the pressure printing equipment is 4 mm / s, the pressure is kept at 12 mpa after contacting the top of the anti-fake glue cap, and the uv lamp is irradiated for 4 seconds.

[0087] S8, chip packaging, the anti-fake glue cap is fixed on the jig, a groove is processed on the top of the anti-fake glue cap by the machining center, conductive silver glue is applied at the bottom of the groove, the rfid chip is sucked by the mechanical hand and placed in the center of the groove, 0.8n pressure is applied for 8 seconds, then the anti-fake glue cap is baked in a 40°C oven for 30 minutes, finally, the rfid chip 6 is coated with epoxy resin by the glue dispenser, covering the chip and the edge by 0.2 mm, and cured at 80°C for 90 minutes.

[0088] S9.1, optical performance detection, clear lines: multi-angle spectrophotometer is used to measure 0°, 45°, and 90° color values, l*=45±2, a*=50±2, and b*=10±2 at 0°;

[0089] l*=40±2, a*=-10±2, and b*=60±2 at 45°;

[0090] 90° l*=35±2, a*=20±2, b*=-40±2, color difference value delta e is all less than or equal to 2;

[0091] Dark lines: 532nm laser vertical irradiation, spectrometer detects first-order diffraction efficiency is greater than or equal to 32%, diffraction pattern is collected by ccd camera, and the coincidence degree is greater than or equal to 96% compared with the standard template.

[0092] S9.2, check point: 20 points are randomly selected, three coordinate measurement position deviation, maximum value is less than or equal to 0.25mm, height consistency is less than or equal to 0.03mm;

[0093] RFID chip: the RFID card reader reads 10 times at a distance of 8cm, the success rate is 100%, the data transmission time is less than or equal to 0.5 seconds, and the encrypted id is matched with the database;

[0094] Mechanical properties: after the 2 area of the clear line is pasted with 3m tape (model 610), it is quickly torn off, and no ink falls off;

[0095] Code detection, chemical response: wipe the code area with acetone (analytical pure), the color change rate is greater than or equal to 95% within 30 seconds, and the color change is irreversible (no recovery after 24 hours);

[0096] Liquid response: respectively drop tap water, edible oil and ethanol, all should show color within 10 seconds (water→pink, oil→brown, ethanol→blue), and the coloration area is greater than or equal to 90%.

[0097] S10, packaging, the inner packaging is anti-static bag, and silica gel drier is put in, and the outer packaging is corrugated carton.

[0098] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. Anti-counterfeiting rubber cap based on micro-nano optical structure, characterized by: The invention comprises an anti-counterfeiting rubber cap (1), wherein a plurality of bright lines (2) are provided on the outer side of the anti-counterfeiting rubber cap (1), a dark line (3) is provided on the anti-counterfeiting rubber cap (1) between two adjacent bright lines (2), a coding area (4) is further provided on the outer side of the anti-counterfeiting rubber cap (1), a plurality of dividing lines (5) are provided on the top of the anti-counterfeiting rubber cap (1), an anti-counterfeiting chip (6) is fixedly connected to the center of the top of the anti-counterfeiting rubber cap (1), and a plurality of check points (7) are provided on the top of the anti-counterfeiting rubber cap (1) near the dividing lines (5).

2. The anti-counterfeiting rubber cap based on micro-nano optical structure according to claim 1, characterized in that: The bright pattern (2) is formed by stacking multiple layers of interference-type light-variable pigment transparent films.

3. The anti-counterfeiting rubber cap based on micro-nano optical structure according to claim 1, characterized in that: The dark pattern (3) is a micro-nano optical structure, and polymethyl methacrylate is used as a micro-nano structure carrier.

4. The anti-counterfeiting rubber cap based on micro-nano optical structure and the preparation method thereof according to claim 1, characterized in that: The coding area (4) is sprayed with chemically sensitive materials and hydrophilic color-changing materials.

5. The anti-counterfeiting rubber cap based on micro-nano optical structure according to claim 1, characterized in that: The anti-counterfeiting chip (6) is an ultra-high frequency RFID chip.

6. A preparation method for preparing the anti-counterfeiting rubber cap according to any one of claims 1 to 5, comprising the following steps: S1. Material preparation and base material processing: low-density polyethylene granules are selected with a melt flow rate of 190℃ / 2.16kg, controlled at 2.0-3.0g / 10min, and a density of 0.920-0.925g / cm³. They are first screened with a 100-mesh vibrating screen to remove impurities, then placed in a hot air circulation drying oven and dried at 80℃ for 4 hours, turning the granules every hour to ensure that the moisture content drops below 0.05%. The dried granules are placed in sealed bags, marked with the batch and drying time, and set aside. S1.

1. Preparation of bright grain materials: Interference-type optically variable pigments using flaky titanium dioxide-silicon dioxide composite particles with a particle size distribution of 12-18 μm, where the titanium dioxide layer is 20-30 nm thick and the silicon dioxide layer is 30-40 nm thick. Mix with acrylic resin in a mass ratio of 1:3, pour into a planetary mixing tank, and set the stirring parameters to 280 r / min for revolution and 750 r / min for rotation. Stir for 50 minutes at 23-25°C, stopping the machine three times to clean the tank wall with a scraper to ensure that there are no agglomerated particles. After preparation, filter with 400-mesh nylon filter cloth, place in a brown glass bottle, seal, and store below 20°C. S1.2, dark pattern (3) Material preparation, the micro-nano structure carrier uses polymethyl methacrylate particles with a molecular weight of 300,000-350,000 and a transmittance of ≥92%. An electron beam lithography system is used to engrave a micro-nano grating on the surface of the silicon-based mold with a period of 350-450nm and a depth of 60-80nm. The pattern includes the brand logo and diffraction stripes. After photolithography, the structure is deepened by reactive ion etching; S2, auxiliary material preparation and inspection, obtain matte silver-gray UV ink, epoxy resin, RFID chip (6); Matte silver-grey UV ink test viscosity: 3200±200mPa・s at 25°C. 100μm wet film was prepared using an applicator. After UV curing, adhesion and scratch resistance were tested. No scratches were observed under a force of 750g. The gel time of epoxy resin is 40-50min at 80℃. After curing, the hardness is shored85±2 and the transmittance in the 400-800nm ​​band is ≥91%. 50 RFID chips are randomly selected from each batch, and the test reading distance is 6-9cm and the data retention time is ≥10 years to ensure the uniqueness of the ID and no duplicate codes; S3, injection molding step, the injection molding equipment a hopper is polyethylene granules, and the injection molding equipment b hopper is polymethyl methacrylate granules; S3.

1. For the injection of polyethylene in the base layer, a closed-loop controlled servo injection system is used. First, the air in the front end of the barrel is evacuated at a pre-injection speed of 5 mm / s. Then, the formal injection is started and the injection is directed to the base layer area. When the cavity volume reaches 85%, the speed is increased in three steps. The injection step process is as follows: The first speed is 30mm / s, filling 30% of the cavity, corresponding to the section from the mold main channel to the cavity entrance, with a pressure of 90mpa±2mpa. The melt flow sensor ensures the smooth advancement of the front edge. The second speed is 50 mm / s, filling to 60% of the cavity. When the melt front reaches 5 mm from the edge of the dark pattern (3), the infrared detector triggers the speed increase and the pressure is simultaneously raised to 95 MPa to avoid insufficient base layer molding; The third speed is 20mm / s, with buffering before pressure holding. When the cavity is filled to 85%, the pressure is reduced to 80mpa. The pre-molded contour of the base layer is confirmed by the in-mold displacement sensor to reserve precise space for the subsequent polymethyl methacrylate injection. During injection molding, a 15mm×5mm rectangular coding area is reserved on the side of the anti-counterfeiting rubber cap 91; S3.2, dark pattern (3) Polymethyl methacrylate injection, after the polyethylene base layer injection is completed, wait for 0.8 seconds, that is, to ensure that the polyethylene base layer is initially shaped before starting, use low-speed precision injection, the injection process is as follows: Initially at 10 mm / s, filling 5% of the cavity, the polymethyl methacrylate melt was controlled by a micro flow valve to slowly flow into the dark pattern (3) area to avoid interface mixing caused by impact on the base layer; Then it rises to 25 mm / s to fill the remaining 10% of the cavity, and the pressure is maintained at 100 MPa ± 2 MPa. The pressure sensor in the mold monitors the pressure in the dark pattern (3) area in real time, and when it reaches 95 MPa, it triggers the pressure holding preparation signal to ensure that the micro-nano structure is completely filled; S3.3, demoulding, the robot picks up the parts, visually inspects for missing parts and flash, and places qualified parts into the transfer tray; S3.4, post-processing, unqualified parts are marked and stored separately, qualified parts are sent to the laser trimming machine, trimmed along the parting line, and after trimming, the workpiece enters the ultrasonic cleaning line for cleaning; S4, the production of bright lines, the anti-counterfeiting rubber cap (1) is fixed on the pneumatic workbench, the reference edge is identified by the CCD visual system, the bright line (2) area is treated with a plasma treatment machine for 2.5 seconds, and immediately tested with a contact angle meter after treatment, the surface energy is ≥40mN / m, to ensure good ink adhesion; S4.1, screen printing, choose 350 mesh stainless steel screen, use tensiometer to detect the four sides, the deviation is ≤1n / cm, after printing, let the workpiece stand for 15 seconds, and then enter the UV curing oven; S4.2, curing and protective layer, the UV curing furnace is divided into three sections: pre-curing 1s, main curing 2s, post-curing 1s, total energy 800mj / cm², conveyor belt speed 1.2m / min, after curing, use gloss meter 60° angle detection, bright grain area gloss ≥90gu, then, the anti-counterfeiting rubber cap (1) is installed on the rotating fixture, the vacuum chamber is evacuated to 5×10⁻ 4 After pa, the PC evaporation boat was heated to 290 °C, the evaporation rate was 4-6 nm / s, and the film thickness was controlled at 5 ± 0.3 μm, which was adjusted in real time by a quartz crystal monitor; S5, the production of the coding area, using low-density polyethylene that is consistent with the main body of the rubber cap, and additionally preparing a surface treatment agent containing silane coupling agent KH-550, with a concentration of 3%, to enhance the adhesion between the coding area (4) and the color-changing layer. The treatment agent needs to be filtered through a 0.2 μm filter membrane to ensure that there are no impurities; The color-changing layer material is a color-changing layer pigment formed by mixing a chemically sensitive material and a hydrophilic color-changing material in a mass ratio of 1:

1. The chemically sensitive material is bromocresol green with a purity of ≥98%, and the hydrophilic color-changing material is anhydrous cobalt chloride. Both are ground to a particle size of ≤5μm and mixed with acrylic resin with a solid content of 45%; The isolation layer material is made of polyvinyl alcohol, which is prepared into an 8% aqueous solution, and 0.1% defoaming agent and silicone are added. The solution is stirred magnetically for 30 minutes until it is completely dissolved. The color-changing layer and the isolation layer are coated using a precision scraper coater to evenly coat the color-changing layer material on the pre-treated inkjet printing area (4). Immediately after coating, the material is placed in a hot air oven and dried at 50°C for 10 minutes to form a dry film. If alcohol-soluble inkjet printing ink is used, the isolation layer needs to be covered on the surface of the color-changing layer. The PVA solution is printed on the inkjet printing area using an inkjet printing method. The printing range is 0.5mm larger than the color-changing layer to ensure complete coverage. S6. Separation line printing, using 200 mesh polyester screen, the printing pattern is radial lines, line width 2.0±0.05mm, wipe the screen with alcohol before printing to ensure there is no residual ink, scraper pressure 0.25mpa, speed 30mm / s, after printing under UV lamp curing for 3 seconds, after curing, the line edge is inspected with a microscope, the jagged ≤0.02mm; S7, check point molding, vacuum adsorption fixation of the anti-counterfeiting rubber cap (1), visual identification of the separation line (5), calibration of the x / y axis deviation, and the micro dispensing valve injects UV ink into the mold cavity, the imprinting equipment mold downward speed is 4mm / s, and after contacting the top of the anti-counterfeiting rubber cap (1), the pressure is maintained at 12mpa, and the UV lamp is irradiated for 4 seconds; S8, chip packaging, fix the anti-counterfeiting rubber cap (1) on the fixture, and use the processing center to process the groove on the top of the anti-counterfeiting rubber cap (1), and apply conductive silver glue on the bottom of the groove. The robot picks up the RFID chip and aligns it with the center of the groove. Apply 0.8N pressure for 8 seconds, and then bake the anti-counterfeiting rubber cap (1) in a 40℃ oven for 30 minutes. Finally, apply epoxy resin to the RFID chip (6) using a dispensing machine, covering the chip and the edge 0.2mm, and cure at 80℃ for 90 minutes; S9.

1. Optical performance test, bright streak: Use a multi-angle spectrophotometer to measure the color values ​​at 0°, 45°, and 90°. At 0°, l*=45±2, a*=50±2, and b*=10±2. At 45°, l*=40±2, a*=-10±2, b*=60±2; At 90°, l*=35±2, a*=20±2, b*=-40±2, and the color difference δe is ≤2; Dark pattern: 532nm laser vertical irradiation, spectrometer detection of first-order diffraction efficiency ≥32%, diffraction pattern collected by CCD camera, compared with the standard template, the consistency ≥96%; S9.2, Verification points: Randomly select 20 points, measure the position deviation of the three coordinates, the maximum value is ≤ 0.25mm, and the height consistency is ≤ 0.03mm; RFID chip: The RFID reader reads 10 times at a distance of 8cm with a 100% success rate, data transmission time ≤ 0.5 seconds, and the encrypted ID matches the database; Mechanical properties: The bright grain (2) area was taped with 3m tape and quickly torn off without ink falling off; Coding area detection, chemical response: wipe the coding area with acetone, the color change rate is ≥95% within 30 seconds, and the color change is irreversible, and there is no recovery after 24 hours; Liquid response: Add tap water, cooking oil, and ethanol separately, and color should appear within 10 seconds, with the color development area ≥90%; S10. Packaging: Use anti-static bags as inner packaging and put in silica gel desiccant, and use corrugated boxes as outer packaging.

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