Application of shredded banknote quicksand on mobile phone shell

Abstract

The application relates to the application of shredded banknote flow sand on a mobile phone shell. The core of the application is to construct five layers of currency simulation functional layers on a PET substrate and to be combined with a leak-proof flow sand cavity. The process is divided into three stages: a substrate printing stage: surface treatment and multi-layer anti-fake printing of the PET substrate; a cavity forming stage: double-color injection molding of the flow sand cavity and filling of a medium; and a composite curing stage: accurate adhesion of the substrate and the cavity. By sequentially stacking the five layers of functional layers of gravure printing, UV color printing, fluorescence, laser and scratch resistance on the PET substrate, and combining with the built-in shredded banknote flow sand cavity, the currency culture expression, anti-fake strengthening and zero-leakage sealing are realized.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, and in particular to the application of shredded banknotes and quicksand on mobile phone cases. Background Technology

[0002] Phone cases are an essential protective tool for people. The market is flooded with all kinds of phone cases at various prices, but they are all fairly standard and ordinary, lacking innovation and cultural depth. Currently, some phone cases on the market combine quicksand with phone cases to enhance the dazzling display effect. These quicksand phone cases primarily use two transparent substrates sandwiching a flowing medium (such as colored oil or glitter) to create a dynamic decorative effect, but they have the following drawbacks: Decoration monotony: The filling material is only ordinary sequins or plastic particles, lacking cultural connotation and visual depth; The process is rudimentary: there is no functional linkage between the flowing medium and the shell substrate, making it impossible to achieve value-added features such as anti-counterfeiting and tactile feedback; Leakage risk: The cavity seal relies on adhesive or thermoforming, and the leakage rate can be as high as 12% with long-term use. While there have been attempts to incorporate currency elements into product design, the following problems remain: Technological disconnect: The printing layer only applies to flat decals and cannot simulate the intaglio printing feel, fluorescent anti-counterfeiting features, and laser iridescent three-dimensional overlay effect of genuine banknotes; Poor substrate adaptability: Traditional gravure printing and cold foil stamping processes require a rigid printing surface, which cannot achieve high-precision registration on curved mobile phone cases (error > 0.3mm).

[0003] Simple structure: only a single layer of anti-counterfeiting features, easy to counterfeit; Unresolved issue of multi-process integration: poor ink compatibility between gravure printing and UV printing leads to interlayer delamination (adhesion < 2B grade); Detached from consumer electronics scenarios: Not adapted to the curved structure, wear resistance requirements, and dynamic carrier characteristics of mobile phone cases. Summary of the Invention

[0004] The main purpose of this invention is to provide the application of shredded banknotes in mobile phone cases. Through multi-process integration, curved surface overprinting precision, and dynamic and static visual linkage, it not only solves the defects existing in the above-mentioned background technology, but also perfectly presents the currency culture by combining shredded banknotes with mobile phone cases. It makes full use of the old banknotes recycled by major banknote printing plants and the fragments of waste banknotes after printing, which is both environmentally friendly and creative, and also allows discarded currency to embark on a new mission.

[0005] It should be noted that the shredded banknotes used in this invention were obtained and produced under the legal and compliant authorization of the various banknote printing plants under the China Banknote Printing and Minting Corporation, and there are no illegal issues involved in the provisions of laws and regulations.

[0006] To achieve the above objectives, the present invention relates to the application of shredded banknote quicksand in mobile phone cases, and its preparation method includes the following steps: S1. Substrate pretreatment: Provide a PET substrate layer with a light transmittance of ≥90% and a thickness of 0.1–0.3mm, and perform corona treatment on one side of it; S2. Gravure printing texture molding: Gravure printing process is used on the treated surface of PET substrate to form a three-dimensional tactile texture layer with a depth of 20–50μm under a pressure of 8–15MPa and a curing temperature of 60–80℃. S3, UV color printing: Color inks are applied to the gravure texture layer by a letterpress UV printing process, and then cured by ultraviolet light to form a pattern layer with a resolution of ≥300dpi; S4. Construction of fluorescent anti-counterfeiting layer: Colorless fluorescent ink is coated on the colored pattern layer, and after drying, an anti-counterfeiting layer that shows color under 365nm ultraviolet light is formed. S5, Laser Iridescent Composite: A laser film is pressed onto the surface of the fluorescent anti-counterfeiting layer using a cold foil stamping process, and an iridescent layer is formed after the carrier is peeled off. S6. Anti-scratch coating: Spray polyurethane anti-scratch coating onto the surface of the laser iridescent layer and cure to form a transparent wear-resistant layer with a hardness ≥3H. S7. Shredded banknote quicksand cavity injection molding: The mobile phone case base is formed by a two-color injection molding process, in which the inner layer is a PC / TPU substrate with a sealed cavity of 0.5–2mm thickness, and the outer layer is a rigid plastic frame covering the cavity; S8. Shredded banknote quicksand medium filling: Mix shredded banknotes, glycerin and suspending agent in a weight ratio of 10–30:60–80:5–10, inject into the cavity and then seal by ultrasonic welding. S9. Substrate Composite Curing: Apply UV adhesive to the untreated surface of the PET substrate layer, align and press it into the groove on the back of the phone case substrate, and cure it with ultraviolet light to form an integrated structure.

[0007] Preferably, the intaglio pattern in step S2 and the shredded banknote sand layer in step S8 form a visually linked anti-counterfeiting combination, and the shredded banknote sand creates a "banknote falling" visual effect.

[0008] Preferably, in S4, the fluorescent anti-counterfeiting layer contains dual-band responsive ink that appears green under 254nm ultraviolet light and red under 365nm ultraviolet light.

[0009] Preferably, in step S7, an elastic silicone ring and a PTFE microporous filter membrane with a pore size ≤ 5 μm are pre-embedded at the edge of the shredded banknote quicksand cavity to form a leak-proof buffer structure.

[0010] Preferably, in step S3, the UV color printing employs a three-stage overprinting process: The initial printing uses CMYK four-color inks to form the basic pattern; Pearlescent ink is applied selectively during secondary printing; Three layers of transparent varnish are applied to enhance the three-dimensional effect.

[0011] The application of the shredded banknote quicksand provided by this invention on mobile phone cases: 1. By combining three anti-counterfeiting technologies—an intaglio texture layer (20-50μm three-dimensional tactile feel), a dual-band fluorescent layer (254nm / 365nm dual-color response), and a laser iridescent layer (1.2μm grating diffraction)—multi-dimensional verification of "tactile feel, visible light, and ultraviolet light" is achieved. Counterfeiting requires simultaneously mastering three core technologies: intaglio engraving, rare-earth fluorescent formula, and nano-grating embossing. The cost of counterfeiting is 300 times higher than that of conventional mobile phone cases. 2. The pre-embedded leak-proof structure (silicone ring + PTFE microporous filter membrane) ensures that the cavity maintains its sealing integrity under thermal shock of -40℃ to 85℃. It has passed 100 high and low temperature cycle tests without leakage, completely solving the pain point of the industry average leakage rate of 12%. 3. By adopting corona pretreatment (≥50dyn / cm) + three-stage UV positioning and overprinting process, the overprinting error is ≤0.05mm on a PET substrate with a curvature radius of 5mm (≥0.3mm in traditional process), ensuring that the edges of the imitation currency pattern are sharp and without ghosting. 4. The interplay between the shredded banknotes and the static intaglio printing creates a spatial connection, presenting a dynamic cultural narrative of "banknotes falling" when tilted, perfectly showcasing monetary culture.

[0012] 5. The 40μm depth of the intaglio printing layer, combined with the 4H hardness of the scratch-resistant layer, simulates the friction coefficient of the intaglio printing area of ​​RMB banknotes at 0.35±0.05 (GB / T 10006 standard), improving the tactile feedback recognition accuracy by 300%. 6. Make full use of the old banknotes recycled by major banknote printing plants and the fragments of discarded banknotes. This is both environmentally friendly and creative, and it also gives discarded currency a new purpose. The fragmented banknotes are obtained under the legal and compliant authorization of major banknote printing plants under the China Banknote Printing and Minting Corporation, and comply with Article 26 of the "Regulations on the Administration of Renminbi". 7. UV adhesive composite curing (strength ≥8N / cm) replaces traditional hot pressing welding, avoiding deformation of the flow sand cavity caused by high temperature (hot pressing defect rate 15%→0%), and improving the production line yield to 99.2%. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0014] Figure 1 A flowchart illustrating the manufacturing method of the shredded banknote quicksand phone case provided in this embodiment of the invention; Figure 2 This is a system diagram illustrating the operational steps, technical principles, and system diagrams provided in the embodiments of the present invention.

[0015] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] In this embodiment of the invention, the application of shredded banknote quicksand on a mobile phone case is achieved through nine precise processes. The core of this invention involves constructing five layers of banknote-like functional layers on a PET substrate, which are then combined with a leak-proof quicksand cavity. The process is divided into three stages: Substrate printing stage (steps 1-6): PET substrate surface treatment and multi-layer anti-counterfeiting printing; Cavity forming stage (steps 7-8): Two-color injection molding of the quicksand cavity and filling with medium; Composite curing stage (step 9): The substrate and the cavity are precisely bonded.

[0018] Reference Figure 1 The specific process flow is as follows: 1. PET substrate pretreatment Objective: To improve the adhesion of subsequent inks.

[0019] operate: A transparent PET film (Toray Industries TL-246, Japan) with a thickness of 0.25mm and a light transmittance of 92% was selected. After being treated by a corona treatment machine (power 2kW, conveying speed 10m / min), the surface tension was increased from 38dyn / cm to 52dyn / cm.

[0020] Principle: Corona discharge causes polar groups to be generated in the PET molecular chains, which enhances ink affinity.

[0021] 2. Gravure texture forming Objective: To simulate the three-dimensional tactile feel of real banknotes.

[0022] operate: Using a gravure printing press (Shaanxi Beiren AJ-1040), the printing cylinder engraving depth is 40μm (including the "100" lettering and peony flower pattern); Coated with epoxy resin tactile ink (Guangzhou Huicai HC-T01), printing pressure 12MPa; Curing is achieved by drying with hot air at 70℃ for 60 seconds.

[0023] Principle: Ink is stored in the cells of the gravure printing plate and transferred to the substrate, forming a micron-level texture.

[0024] 3. UV color printing Objective: To achieve high-precision pattern reproduction.

[0025] operate: First print: The base pattern is printed using CMYK four-color inks (Pantone standard colors) at a resolution of 600 dpi; Secondary printing: Apply pearlescent ink (DuPont GP-203) to specific areas to enhance metallic luster; Three printing processes: full-page coating with transparent varnish, 10μm thick; Cured with a 395nm UV lamp (energy 800mJ / cm²).

[0026] Principle: Three-stage overprinting solves color difference on curved substrates, and UV curing instantly cross-links the ink.

[0027] 4. Construction of Fluorescent Anti-counterfeiting Layer Objective: To implant concealed anti-counterfeiting features.

[0028] operate: Anilox roller (200 lines / in) coated with dual-band fluorescent ink (containing europium / terbium complex), wet film thickness 8μm; Dry with hot air at 80℃ for 30 seconds; Color rendering characteristics: 254nm ultraviolet light → green fluorescence 365nm ultraviolet light → red fluorescence Principle: Rare earth ions emit light through energy level transitions when excited by ultraviolet light.

[0029] 5. Laser iridescent composite Objective: To enhance dynamic optical effects.

[0030] operate: Apply water-based cold foil (Kurz KT-501 from Germany) to a film thickness of 3μm; Lamination of holographic laser film (Suzhou Suda Vigor, grating period 1.2μm); Composite under 0.8MPa pressure, peeling off the carrier membrane at a speed of 15m / min.

[0031] Principle: Cold hot stamping adhesive dissolves the aluminum layer of the laser film, transferring the diffraction structure to the substrate.

[0032] 6. Scratch-resistant coating Purpose: To protect the printed layer from abrasion.

[0033] operate: Electrostatic spraying of polyurethane UV-curable coating (Japan DIC UVHC-300), film thickness 15μm; Cured with 365nm UV lamp (energy 1000mJ / cm²), achieving a hardness of 4H (ASTM D3363).

[0034] Principle: Polyurethane cross-links to form a dense network structure that resists scratches.

[0035] 7. Shredded banknote quicksand cavity injection molding Objective: To construct a leak-proof quicksand container.

[0036] Operation: Two-color injection molding machine (Sumitomo SE-1800) performs molding in two steps: Inner layer: Transparent TPU (BASF 85A) injection molded cavity matrix, 1.2mm thick; Outer layer: Black PC (SABIC LEXAN-943) frame; Pre-embedded leak-proof structure: A silicone ring (Shore hardness 30A) is embedded in the edge of the cavity to absorb impact; Cover with a PTFE microporous membrane (3μm pore size) to prevent particle leakage.

[0037] Principle: TPU elastic cushioning + PC rigid support, silicone ring to compensate for thermal expansion and contraction.

[0038] 8. Filling with shredded banknote quicksand medium Objective: To inject dynamic shredded banknote quicksand medium.

[0039] operate: Formula mixture: 75 parts glycerin + 8 parts suspending agent + 17 parts shredded banknotes; Sealing: Ultrasonic welding (20kHz / 0.5MPa) after injection into the cavity, sealing width 1.5mm.

[0040] Principle: When tilted, it presents a dynamic cultural narrative of "banknotes falling", perfectly showcasing monetary culture.

[0041] 9. Substrate composite curing Objective: To integrate the printing substrate and the cavity.

[0042] operate: UV adhesive (Japanese Sankin TB-3155) is applied to the back of the PET substrate, with an adhesive thickness of 50μm; Align and press into the groove on the back panel of the phone case, then cure under ultraviolet light for 30 seconds (intensity 120mW / cm²). Peel strength ≥8N / cm (GB / T 2792).

[0043] Principle: UV adhesive undergoes free radical polymerization to form a permanent bond.

[0044] The above operating steps and technical principles are illustrated in the system diagram as follows: Figure 2 As shown.

[0045] The method for preparing the shredded banknote quicksand mobile phone case provided by the present invention involves sequentially stacking five functional layers—intaglio printing, UV color printing, fluorescence, laser, and scratch resistance—on a PET substrate, and combining them with a built-in shredded banknote quicksand cavity to achieve expression of currency culture, enhanced anti-counterfeiting, and zero-leakage sealing.

[0046] After testing, the technical specifications are as follows: Interlayer adhesion 4B grade (100-grid test) 2B level overprint accuracy ≤0.05mm ≥0.3mm Leakage rate 0% (after accelerated aging) 12% Anti-counterfeiting levels 4 layers (gravure / fluorescent / laser / infrared) Single-layer printing Example Performance Verification

[0047] Case Study: iPhone 16 Pro Phone Case 1. Abrasion resistance test: 0000# steel wool, subjected to a 500g load and 500 rubs, shows no visible scratches on the scratch-resistant layer; Anti-counterfeiting verification: 254nm UV lamp: The gravure-printed peony flower shows green fluorescence; 365nm UV lamp: The number "100" shows red fluorescence; 3. Sealing test: -40℃ (2h) → 85℃ (2h) cycled 100 times, zero leakage; Visual linkage: When tilted, it presents a dynamic cultural narrative of "banknotes falling", perfectly showcasing monetary culture.

[0048] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. The application of shredded banknotes and quicksand on mobile phone cases, characterized in that, Includes the following steps: S1. Substrate pretreatment: Provide a PET substrate layer with a light transmittance of ≥90% and a thickness of 0.1–0.3mm, and perform corona treatment on one side of it; S2. Gravure printing texture molding: Gravure printing process is used on the treated surface of PET substrate to form a three-dimensional tactile texture layer with a depth of 20–50μm under a pressure of 8–15MPa and a curing temperature of 60–80℃. S3, UV color printing: Color inks are applied to the gravure texture layer by a letterpress UV printing process, and then cured by ultraviolet light to form a pattern layer with a resolution of ≥300dpi; S4. Construction of fluorescent anti-counterfeiting layer: Colorless fluorescent ink is coated on the colored pattern layer, and after drying, an anti-counterfeiting layer that shows color under 365nm ultraviolet light is formed. S5, Laser Iridescent Composite: A laser film is pressed onto the surface of the fluorescent anti-counterfeiting layer using a cold foil stamping process, and an iridescent layer is formed after the carrier is peeled off. S6. Anti-scratch coating: Spray polyurethane anti-scratch coating onto the surface of the laser iridescent layer and cure to form a transparent wear-resistant layer with a hardness ≥3H. S7. Shredded banknote quicksand cavity injection molding: The mobile phone case base is formed by a two-color injection molding process, in which the inner layer is a PC / TPU substrate with a sealed cavity of 0.5–2mm thickness, and the outer layer is a rigid plastic frame covering the cavity; S8. Shredded banknote quicksand medium filling: Mix shredded banknotes, glycerin and suspending agent in a weight ratio of 10–30:60–80:5–10, inject into the cavity and then seal by ultrasonic welding. S9. Substrate Composite Curing: Apply UV adhesive to the untreated surface of the PET substrate layer, align and press it into the groove on the back of the phone case substrate, and cure it with ultraviolet light to form an integrated structure.

2. The application of shredded banknote quicksand on a mobile phone case as described in claim 1, characterized in that, The intaglio pattern in step S2 and the shredded banknote sand layer in step S8 form a visually linked anti-counterfeiting combination, and the shredded banknote sand creates a "banknote falling" visual effect.

3. The application of shredded banknote quicksand on a mobile phone case as described in claim 1, characterized in that, In S4, the fluorescent anti-counterfeiting layer contains dual-band responsive ink that appears green under 254nm ultraviolet light and red under 365nm ultraviolet light.

4. The application of shredded banknote quicksand on a mobile phone case as described in claim 1, characterized in that, In S7, an elastic silicone ring and a PTFE microporous filter membrane with a pore size ≤5μm are pre-embedded at the edge of the shredded banknote quicksand cavity to form a leak-proof buffer structure.

5. The application of shredded banknote quicksand on a mobile phone case as described in claim 1, characterized in that, In S3, UV color printing employs a three-stage overprinting process: The initial printing uses CMYK four-color inks to form the basic pattern; Pearlescent ink is applied selectively during secondary printing; Three layers of transparent varnish are applied to enhance the three-dimensional effect.

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