Process for preparing a pearl card sleeve

Abstract

The application belongs to the technical field of packaging printing and special paper processing, and particularly relates to a preparation process of a pearl card cover, and the specific step process of the preparation process is as follows: fluorine crystal mica base material synthesis, pearl hydrolysis coating modification, pearl multi-stage purification washing, drying treatment, high-temperature setting calcination, precise mixing and powder proportioning, multi-layer differential functional film co-extrusion flow casting, and post-treatment after forming; through customizing and pasting a roller to rework a micro-frosted texture and independently synthesizing a fluorine crystal mica diffuse reflection pearl system, a matte frosted surface and soft pearl reflection are realized, and there is no problem of mirror surface highlight glare; the ordinary pearl card cover can only realize high-brightness mirror surface pearl, and cannot form a frosted texture; the independently synthesized fluorine crystal mica pearl material is high in purity, good in dispersity, delicate and stable in color, and free of natural mica impurity defects.

Description

Technical Field

[0001] This invention relates to the field of packaging printing and specialty paper processing technology, specifically a pearlescent card sleeve preparation process. Background Technology

[0002] Pearlescent card sleeves, as high-end card packaging products, are widely used in cultural and creative collectible cards, high-end gift cards, business membership cards, hotel access cards and other fields. With their unique pearlescent decorative texture, they have a stronger visual appeal and product grade compared to ordinary paper card sleeves, and are currently the mainstream product in the high-end packaging field.

[0003] The biggest technical drawback of conventional pearlescent card sleeves is their monotonous surface texture. They only have a high-gloss mirror pearlescent reflective effect, which generally suffers from strong and glaring reflection, a smooth surface that is easy to attract fingerprints, and a cheap feel from the mirror reflective surface. They cannot achieve the composite texture of a matte base combined with soft pearlescent reflection that is urgently needed for high-end packaging.

[0004] Therefore, a pearlescent ferrule manufacturing process is proposed to address the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a pearlescent cassette manufacturing process to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a pearlescent card sleeve manufacturing process, the specific steps of which are as follows: Step 1: Synthesis of Fluorocrystalline Mica Substrate: Artificial fluorocrystalline mica is synthesized using an internal heating melt crystallization method. Quartz powder, fused magnesia, potassium fluorosilicate, and alumina powder are selected according to their mass proportions and mixed evenly. The mixture is then placed in a high-temperature melting furnace and heated to 1380-1450℃ for melting and crystallization. The mixture is kept at a constant temperature for 2.5-4 hours, and then slowly cooled down at a rate of 3-5℃ / min to crystallize. The mixture is then allowed to cool naturally to room temperature to obtain synthetic fluorocrystalline mica sheets. Step 2, Pearl hydrolysis coating modification: The synthesized fluorinated mica is added to deionized water to prepare a uniform suspension with a mass concentration of 18%-25%, and the temperature is maintained at 75-85℃ and the stirring speed is 350-450r / min; the titanium salt coating solution is slowly added dropwise, and a nano titanium dioxide film is uniformly coated on the surface of the fluorinated mica sheets through liquid phase uniform hydrolysis deposition. Step 3, Pearlite Multi-stage Purification and Washing: After hydrolysis and coating, allow the pearlite suspension to settle for 25-40 minutes, drain by siphon, and wash with multi-stage countercurrent pure water 3-5 times; repeatedly rinse to remove residual free acid, salt impurities and unreacted precursors on the powder surface, and continuously monitor the pH of the washing solution to a neutral range of 6.8-7.2. Step 4: Drying treatment: Spread the washed and purified fluorine crystal mica pearlescent filter cake evenly, with the thickness of the spread material controlled at 2-4cm; use a segmented low-temperature hot air drying process to slowly remove the internal moisture; after drying, perform preliminary dispersing and sieving to select 1000-1200 mesh powder to obtain loose and uniform primary pearlescent powder. Step 5, High-Temperature Shaping and Calcination: Place the dried and sieved pearlescent powder into a high-temperature calcination device, heat it to 880-950℃, and calcine it at a constant temperature for 1.5-2.5 hours to ensure that the titanium dioxide crystal form coated on the surface is completely stable and solidified; after calcination, cool it to below 100℃ in the furnace and remove it from the furnace. Then, use a 1200-1500 mesh fine sieve to obtain the finished high-purity fluorine crystal mica pearlescent material. Step Six: Precisely Mix Powder Ratios: Precisely mix the powders according to the functional requirements of the membrane layer; Step 7: Co-extrusion casting of multilayer differentiated functional films: Composite films are prepared using multilayer co-extrusion casting equipment; Step 8: Post-molding treatment: After casting, the composite film is cooled and shaped at a constant temperature of 25-32℃, then pulled and wound at a uniform speed, and aged at room temperature for 48-72 hours to eliminate internal stress. After lamination, precision die-cutting, pressing, and cutting, a high-end pearlescent card sleeve with a surface that has both a matte frosted texture and a soft pearlescent diffuse reflection effect is finally obtained.

[0007] Preferably, in step one, 25-35 parts by weight of quartz powder, 30-40 parts by weight of fused magnesia, 15-25 parts by weight of potassium fluorosilicate and 10-20 parts by weight of alumina powder are selected; the resulting synthetic fluorine crystal mica flakes have regular layers and a particle size concentrated in the range of 8-25 μm.

[0008] Preferably, in step two, the pH value of the system is kept stable at 1.8-2.5 throughout the reaction process, and the hydrolysis reaction time is 2.5-3.5 hours to ensure that the coating layer has a uniform thickness, no agglomeration, and no leakage.

[0009] Preferably, in step four, the segmented low-temperature hot air drying process includes: the first stage temperature is 55-65℃, and the drying time is 2-3 hours; the second stage temperature is 70-80℃, and the drying time is 3-4 hours.

[0010] Preferably, in step six, the proportioning parameters for each layer are as follows: Layer A materials: 94-96 wt% RP225N raw material, 4-6 wt% self-made fluorine crystal pearlite; Layer B raw materials: HD601CF raw material 97-98.5wt%, color masterbatch 1.5-3wt%; C-layer raw materials: HD601CF raw material 55-65wt%, DF740 raw material 32-42wt%, color masterbatch 1.5-3wt%; D-layer raw materials: 50-60wt% RP225N raw material, 37-47wt% DF740 raw material, 1.5-3wt% color masterbatch; The mixing time for each layer of material is controlled at 10-15 minutes, and the mixing speed is 800-1000 r / min. After mixing, the mixture is sealed and left to stand for 20-28 hours to ensure that the powder and plastic granules are highly compatible and evenly dispersed, and to eliminate defects such as particle spots, color differences, and bursting points on the film surface.

[0011] Preferably, in step seven, the thickness of layer A is 0.02mm, and a custom-made frosted cooling roller is used for full-process roller forming. The roller surface roughness is Ra1.2-1.8μm, and the roller temperature is controlled at 28-35℃ to replicate a uniform micro-frosted texture and form a unique frosted reflective effect. Layer B has a thickness of 0.03 mm; The thickness of layer C is 0.03 mm; The thickness of layer D is 0.03 mm; The co-extrusion temperature is controlled as follows: feeding section 190-205℃, melting section 210-225℃, die head temperature 220-230℃, production line speed 8-12m / min, four layers are extruded and shaped synchronously, and the interlayer bonding is tight without delamination.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1) By customizing the roller to replicate the micro-frosted texture and independently synthesizing the fluorine crystal mica diffuse reflection pearlescent system, a matte frosted surface and soft pearlescent reflection are achieved, without the problem of glaring mirror high gloss. Ordinary pearlescent card sleeves can only achieve high-gloss mirror pearlescent, but cannot form a frosted texture. 2) Self-synthesized fluorine crystal mica pearlescent material, with high purity, good dispersibility, delicate and stable color, and no natural mica impurities or defects; 3) The four-layer functional design is as follows: the outer layer is responsible for the appearance effect, the middle layer is responsible for rigidity, the transition layer is responsible for stress balance, and the inner layer is responsible for adhesion and stability. Its comprehensive performance is far superior to that of ordinary single-layer and double-layer pearlescent film sleeves. 4) The film surface is fingerprint-resistant, scratch-resistant, weather-resistant, and does not yellow. It has a delicate and high-end feel, solving the industry pain points of traditional pearlescent card sleeves, which are smooth, easy to leave fingerprints, reflective, and cheap. Attached Figure Description

[0013] Figure 1 This is a flowchart of the preparation process. Figure 2 This is a diagram showing the raw material composition of the membrane. Detailed Implementation

[0014] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Example: Please see Figure 1-2 The present invention provides a technical solution: A process for manufacturing pearlescent card sleeves, the specific steps of which are as follows: Step 1: Synthesis of Fluorocrystalline Mica Substrate: Artificial fluorocrystalline mica is synthesized using an internal heating melt crystallization method. Quartz powder, fused magnesia, potassium fluorosilicate, and alumina powder are selected according to their mass proportions and mixed evenly. The mixture is then placed in a high-temperature melting furnace and heated to 1380-1450℃ for melting and crystallization. The mixture is kept at a constant temperature for 2.5-4 hours, and then slowly cooled down at a rate of 3-5℃ / min to crystallize. The mixture is then allowed to cool naturally to room temperature to obtain synthetic fluorocrystalline mica sheets. Fluorocrystalline mica is prepared using an artificial internal thermal melting crystallization method. Compared to natural mica, it has fewer impurities and a smoother, more regular lamellar structure, free from the black spots, impurities, and cracks found in natural minerals, ensuring the purity of the pearlescent pigment base color from the source. Strict control of high-temperature melting (1380-1450℃), prolonged heat preservation, and slow gradient cooling allows for the growth of uniformly sized lamellar crystals, ensuring uniform coating of the subsequent titanium dioxide film and forming a soft, diffuse pearlescent sheen without the appearance of excessively bright, localized specular highlights. The artificially synthesized substrate exhibits stable performance and minimal batch-to-batch variation, avoiding inconsistent quality of purchased raw materials and ensuring uniform pearlescent color in each batch of film. This provides a high-quality matrix for achieving the composite effect of frosted and softly reflective surfaces. Step 2, Pearl hydrolysis coating modification: The synthesized fluorinated mica is added to deionized water to prepare a uniform suspension with a mass concentration of 18%-25%, and the temperature is maintained at 75-85℃ and the stirring speed is 350-450r / min; the titanium salt coating solution is slowly added dropwise, and a nano titanium dioxide film is uniformly coated on the surface of the fluorinated mica sheets through liquid phase uniform hydrolysis deposition. Mica is prepared into a suspension with a concentration of 18%-25%, and with constant temperature and stirring speed, the mica flakes are evenly dispersed in water, preventing them from piling up and agglomerating. This ensures that each flake is uniformly contacted by the titanium salt solution. Through slow liquid-phase hydrolysis deposition, a nano-titanium dioxide film is continuously generated on the mica surface. The film has a uniform thickness, and light is diffusely reflected, forming a warm and soft pearlescent sheen without producing a glaring mirror-like shine, perfectly matching the visual effect of a matte surface. The stable hydrolysis environment avoids uneven coating thickness, eliminating quality defects such as light spots, streaks, and localized whitening or mottling in the later film. Step 3, Pearlite Multi-stage Purification and Washing: After hydrolysis and coating, allow the pearlite suspension to settle for 25-40 minutes, drain by siphon, and wash with multi-stage countercurrent pure water 3-5 times; repeatedly rinse to remove residual free acid, salt impurities and unreacted precursors on the powder surface, and continuously monitor the pH of the washing solution to a neutral range of 6.8-7.2. The hydrolysis reaction system contains a large amount of free acid, soluble inorganic salts, and unreacted titanium salt precursors. If these remain inside the powder, they will precipitate white spots and pinholes during high-temperature plastic extrusion, causing defects on the film surface. A process involving sedimentation siphon and multi-stage countercurrent pure water washing is employed to gradually and thoroughly remove soluble impurities until the washing water is nearly neutral. This significantly improves the purity of the pearlescent powder, preventing impurities from causing yellowing, precipitation, or localized powdering of the film, ensuring a clean and smooth surface and a complete and continuous frosted texture on the four-layer co-extruded film. Step 4: Drying treatment: Spread the washed and purified fluorine crystal mica pearlescent filter cake evenly, with the thickness of the spread material controlled at 2-4cm; use a segmented low-temperature hot air drying process to slowly remove the internal moisture; after drying, perform preliminary dispersing and sieving to select 1000-1200 mesh powder to obtain loose and uniform primary pearlescent powder. Spread the filter cake to a thickness of 2-4 cm and use segmented low-temperature hot air drying to slowly remove moisture. This prevents rapid moisture vaporization from cracking the flaky mica, protecting the crystal wafers from breakage and maintaining a good pearlescent luster. After drying, sieve to 1000-1200 mesh to separate coarse particles from ultrafine dust, ensuring the powder is loose and free of lumps. Coarse particles can form small bumps on the film surface, disrupting the continuous frosted surface; sieving ensures a smooth and delicate film surface. Thoroughly dry the film to prevent moisture-containing powder from entering the extruder and causing water vaporization, which could form bubbles and pinholes inside the film, ensuring the integrity and continuity of the surface micro-frosted texture. Step 5, High-Temperature Shaping and Calcination: Place the dried and sieved pearlescent powder into a high-temperature calcination device, heat it to 880-950℃, and calcine it at a constant temperature for 1.5-2.5 hours to ensure that the titanium dioxide crystal form coated on the surface is completely stable and solidified; after calcination, cool it to below 100℃ in the furnace and remove it from the furnace. Then, use a 1200-1500 mesh fine sieve to obtain the finished high-purity fluorine crystal mica pearlescent material. Constant temperature calcination at 880-950℃ allows the titanium dioxide coating on the mica surface to complete the crystal transformation, resulting in a more stable crystal structure and significantly improving the heat resistance of the pearlescent material. It can withstand the high temperature of about 220℃ in the co-extrusion process without turning black, losing its gloss, or changing color due to heat. After calcination, it is finely sieved again to further break up agglomerated particles, improve the dispersibility of the powder in PP resin, and ensure that the pearlescent particles in the A layer are evenly distributed and reflect light evenly and consistently. Step Six: Precisely Mix Powder Ratios: Precisely mix the powders according to the functional requirements of the membrane layer; The four layers of the film are formulated with independent ingredients for their respective functions: the surface layer uses a pearlescent blend to achieve the desired appearance; the middle layer uses a high-rigidity raw material to ensure stiffness; the transition layer uses a soft-hard blend to offset internal stress; and the inner layer uses a toughening formula to ensure lamination and die-cutting performance. Pearlescent masterbatch, color masterbatch, and resin particles are thoroughly and rapidly mixed, followed by a long period of sealed curing. This ensures that the additives are fully impregnated by the resin, preventing particle pitting, color differences, and localized melt flocculation during extrusion. This layered formulation allows for the addition of only pearlescent material to the surface layer, while the inner layer contains no pearlescent components. This ensures a frosted reflective effect on the outer surface while saving on expensive pearlescent pigments and controlling production costs.

[0016] Step 7: Co-extrusion casting of multilayer differentiated functional films: Composite films are prepared using multilayer co-extrusion casting equipment; Four layers are co-extruded simultaneously in a single process, with the layers tightly bonded together in the molten state. The film does not delaminate or separate, resulting in a robust overall structure. Layer A is formed by closely adhering to a custom-designed frosted cooling roller, perfectly replicating the microscopic texture of the roller surface onto the outer surface of the film, creating a continuous and uniform matte frosted finish. Simultaneously, fluorinated mica pearlescent powder is evenly dispersed on the surface, ultimately forming a unique matte and pearlescent diffuse reflection effect, overcoming the shortcomings of ordinary pearlescent films with their high-gloss mirror finish. The thickness of each layer is strictly distributed: the thinner surface layer facilitates the replication of fine textures, while the sufficient thickness of the inner layers ensures the rigidity and toughness of the film, resulting in a flat and sturdy finished product that is not prone to curling or deformation. The extrusion temperature is controlled in stages to prevent high-temperature degradation of the pearlescent pigments, ensuring a clean and flawless film surface.

[0017] Step 8: Post-molding treatment: After casting, the composite film is cooled and shaped at a constant temperature of 25-32℃, then pulled and wound at a uniform speed, and aged at room temperature for 48-72 hours to eliminate internal stress. After lamination, precision die-cutting, pressing, and cutting, a high-end pearlescent card sleeve with a surface that has both a matte frosted texture and a soft pearlescent diffuse reflection effect is finally obtained.

[0018] In step one, 25-35 parts by weight of quartz powder, 30-40 parts by weight of fused magnesia, 15-25 parts by weight of potassium fluorosilicate, and 10-20 parts by weight of alumina powder are selected to maintain a fixed formula ratio. After melting and crystallization, the flakes are intact and there are no excessive fine powders or coarse particles. The resulting synthetic fluorocrystalline mica flakes are regular in size, with particle sizes concentrated in the range of 8-25 μm. The medium flake size of 8-25 μm avoids the appearance of raised particle points on the film surface due to excessively large particles, and also avoids the weak pearlescent shimmer due to excessively fine particles. It forms a warm and soft diffuse reflection luster, which is suitable for the visual requirements of surface frosting and reflection. The fixed raw material ratio ensures that the quality of each batch of mica substrate is consistent, guaranteeing the stable performance of each subsequent batch of pearlescent pigments and reducing batch color differences.

[0019] In step two, the pH value of the system is kept stable at 1.8-2.5 throughout the reaction process, and the hydrolysis reaction time is 2.5-3.5 hours to ensure that the coating layer is of uniform thickness, without agglomeration or leakage.

[0020] This acidic range ensures slow and uniform hydrolysis of titanium salts, resulting in a continuous and intact titanium dioxide film that avoids localized excessive thickness that could create a mirror-like shine. Instead, it produces diffuse pearlescent luster that perfectly matches the frosted texture of the surface. Strict control of the reaction time ensures complete coating without any gaps, while preventing over-coating that could cause the powder to turn white and lose its gloss. This effectively avoids uneven coating thickness that could lead to uneven pearlescent luster or mottled light and dark areas on the film surface, ensuring uniform gloss across the entire film. In step four, the segmented low-temperature hot air drying process includes: the first stage temperature is 55-65℃, and the drying time is 2-3 hours; the second stage temperature is 70-80℃, and the drying time is 3-4 hours.

[0021] The first stage involves slow, low-temperature dehydration to remove free surface water, preventing the rapid vaporization of water vapor inside the filter cake from breaking the mica flakes and protecting the integrity of the sheet substrate. The second stage involves moderately increasing the temperature to remove bound water inside the pores and thoroughly drying the product, preventing water-containing powder from entering the extruder and causing bubbles and pinholes. There is no high-temperature rapid drying throughout the process, so the flakes remain intact and the pearlescent effect remains stable and does not diminish. In step six, the proportioning parameters for each layer are as follows: Layer A materials: 94-96 wt% RP225N raw material, 4-6 wt% self-made fluorine crystal pearlite; Layer B raw materials: HD601CF raw material 97-98.5wt%, color masterbatch 1.5-3wt%; C-layer raw materials: HD601CF raw material 55-65wt%, DF740 raw material 32-42wt%, color masterbatch 1.5-3wt%; D-layer raw materials: 50-60wt% RP225N raw material, 37-47wt% DF740 raw material, 1.5-3wt% color masterbatch; The mixing time for each layer of material is controlled at 10-15 minutes, and the mixing speed is 800-1000 r / min. After mixing, the mixture is sealed and left to stand for 20-28 hours to ensure that the powder and plastic granules are highly compatible and evenly dispersed, and to eliminate defects such as particle spots, color differences, and bursting points on the film surface.

[0022] The effects of the four-layer formula design: Layer A: A small amount of fluorine crystal pearlescent material is evenly dispersed in the RP225N matrix, and the pearlescent particles will not clump together. Combined with the roller bonding process, a composite surface layer of frosted and pearlescent material is formed, with a soft and non-glaring gloss. Layer B: Pure rigid PP with color masterbatch, which improves the overall stiffness of the film, makes the card sleeve flat and not soft, and at the same time unifies the base color to avoid the messy pearlescent base color; C layer: Hard material HD601CF and tough material DF740 are blended to balance rigidity and toughness, offset the internal stress generated by multi-layer co-extrusion, and prevent film curling, interlayer cracking and delamination. Layer D: A blend of soft and hard materials, ensuring a tight bond when laminated with cardboard, and preventing cracking and burrs during die-cutting.

[0023] The effects of mixing process parameters: Stir at 800-1000 rpm for 10-15 minutes to fully disperse the pearlescent powder, masterbatch, and plastic particles; then seal and cure for 20-28 hours to allow the additives to fully impregnate the resin matrix. This completely solves defects such as particle pitting, color streaks, and localized bursts that occur during extrusion, resulting in a clean and delicate film surface with a continuous and uniform frosted texture.

[0024] In step seven, layer A (the outermost frosted pearlescent surface) has a thickness of 0.02mm. It is formed using a custom-designed frosted cooling roller with a surface roughness of Ra 1.2-1.8μm and a roller temperature controlled at 28-35℃. This replicates a uniform micro-frosted texture, creating a unique frosted reflective effect. The film adheres tightly to the frosted cooling roller, completely replicating the uniform micro-texture on the roller onto the outer surface of the film, stably forming a continuous matte frosted surface. The roller temperature and film setting speed are moderate, resulting in clear textures without pitting defects. This ultimately achieves a frosted surface that cannot be obtained with ordinary flat roller extrusion, while simultaneously incorporating pearlescent diffuse reflection to create a unique frosted reflective effect. This is the core innovation of this patent, distinguishing it from all existing pearlescent card sleeves. The thickness of layer B (rigid support layer) is 0.03 mm; Layer C (stress buffer transition layer): thickness is 0.03mm; Layer D (inner bonding layer): thickness is 0.03mm; Strictly controlling the thickness of the four layers makes it easier to replicate the fine texture of the roller surface. The three inner layers ensure overall stiffness and toughness, and the thickness is reasonably matched to avoid the texture becoming blurred due to an excessively thick surface layer. The co-extrusion temperature is controlled as follows: feeding section 190-205℃, melting section 210-225℃, die head temperature 220-230℃, production line speed 8-12m / min, four layers are extruded and shaped synchronously, and the interlayer bonding is tight without delamination.

[0025] The low temperature of the feeding section prevents the pearlescent material from being degraded prematurely by heat, the melting section ensures uniform plasticization of the resin, and the stable temperature of the die head ensures stable melt flow. The production line runs at a uniform speed, the film thickness is uniform, the frosted texture is continuous and uninterrupted, and the appearance of the entire card sleeve is extremely consistent. The four layers are synchronously co-extruded into one piece, and the interlayer fusion is strong, so there will be no delamination or delamination during subsequent lamination.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for manufacturing pearlescent card sleeves, characterized in that, The specific steps of this preparation process are as follows: Step 1: Synthesis of Fluorocrystalline Mica Substrate: Artificial fluorocrystalline mica is synthesized using an internal heating melt crystallization method. Quartz powder, fused magnesia, potassium fluorosilicate, and alumina powder are selected according to their mass proportions and mixed evenly. The mixture is then placed in a high-temperature melting furnace and heated to 1380-1450℃ for melting and crystallization. The mixture is kept at a constant temperature for 2.5-4 hours, and then slowly cooled down at a rate of 3-5℃ / min to crystallize. The mixture is then allowed to cool naturally to room temperature to obtain synthetic fluorocrystalline mica sheets. Step 2, Pearl hydrolysis coating modification: The synthesized fluorinated mica is added to deionized water to prepare a uniform suspension with a mass concentration of 18%-25%, and the temperature is maintained at 75-85℃ and the stirring speed is 350-450r / min; the titanium salt coating solution is slowly added dropwise, and a nano titanium dioxide film is uniformly coated on the surface of the fluorinated mica sheets through liquid phase uniform hydrolysis deposition. Step 3, Pearlite Multi-stage Purification and Washing: After hydrolysis and coating, allow the pearlite suspension to settle for 25-40 minutes, drain by siphon, and wash with multi-stage countercurrent pure water 3-5 times; repeatedly rinse to remove residual free acid, salt impurities and unreacted precursors on the powder surface, and continuously monitor the pH of the washing solution to a neutral range of 6.8-7.

2. Step 4: Drying treatment: Spread the washed and purified fluorine crystal mica pearlescent filter cake evenly, with the thickness of the spread material controlled at 2-4cm; use a segmented low-temperature hot air drying process to slowly remove the internal moisture; after drying, perform preliminary dispersing and sieving to select 1000-1200 mesh powder to obtain loose and uniform primary pearlescent powder. Step 5, High-Temperature Shaping and Calcination: Place the dried and sieved pearlescent powder into a high-temperature calcination device, heat it to 880-950℃, and calcine it at a constant temperature for 1.5-2.5 hours to ensure that the titanium dioxide crystal form coated on the surface is completely stable and solidified; after calcination, cool it to below 100℃ in the furnace and remove it from the furnace. Then, use a 1200-1500 mesh fine sieve to obtain the finished high-purity fluorine crystal mica pearlescent material. Step Six: Precisely Mix Powder Ratios: Precisely mix the powders according to the functional requirements of the membrane layer; Step 7: Co-extrusion casting of multilayer differentiated functional films: Composite films are prepared using multilayer co-extrusion casting equipment; Step 8: Post-molding treatment: After casting, the composite film is cooled and shaped at a constant temperature of 25-32℃, then pulled and wound at a uniform speed, and aged at room temperature for 48-72 hours to eliminate internal stress. After lamination, precision die-cutting, pressing, and cutting, a high-end pearlescent card sleeve with a surface that has both a matte frosted texture and a soft pearlescent diffuse reflection effect is finally obtained.

2. The pearlescent card sleeve manufacturing process according to claim 1, characterized in that: In step one, 25-35 parts of quartz powder, 30-40 parts of fused magnesia, 15-25 parts of potassium fluorosilicate and 10-20 parts of alumina powder are selected by weight. The prepared synthetic fluorine crystal mica sheets are well-defined with particle sizes concentrated in the range of 8-25 μm.

3. The pearlescent card sleeve manufacturing process according to claim 1, characterized in that: In step two, the pH value of the system is kept stable at 1.8-2.5 throughout the reaction process, and the hydrolysis reaction time is 2.5-3.5 hours to ensure that the coating layer is of uniform thickness, without agglomeration or leakage.

4. The pearlescent card sleeve manufacturing process according to claim 1, characterized in that: In step four, the segmented low-temperature hot air drying process includes: the first stage temperature is 55-65℃, and the drying time is 2-3 hours; the second stage temperature is 70-80℃, and the drying time is 3-4 hours.

5. The pearlescent card sleeve manufacturing process according to claim 1, characterized in that: In step six, the proportioning parameters for each layer are as follows: Layer A materials: 94-96 wt% RP225N raw material, 4-6 wt% self-made fluorine crystal pearlite; Layer B raw materials: HD601CF raw material 97-98.5wt%, color masterbatch 1.5-3wt%; C-layer raw materials: HD601CF raw material 55-65wt%, DF740 raw material 32-42wt%, color masterbatch 1.5-3wt%; D-layer raw materials: 50-60wt% RP225N raw material, 37-47wt% DF740 raw material, 1.5-3wt% color masterbatch; The mixing time for each layer of material is controlled at 10-15 minutes, and the mixing speed is 800-1000 r / min. After mixing, the mixture is sealed and left to stand for 20-28 hours to ensure that the powder and plastic granules are highly compatible and evenly dispersed, and to eliminate defects such as particle spots, color differences, and bursting points on the film surface.

6. The pearlescent card sleeve manufacturing process according to claim 1, characterized in that: In step seven, the thickness of layer A is 0.02mm. A custom-made frosted cooling roller is used for full-process roller forming. The roller surface roughness is Ra1.2-1.8μm, and the roller temperature is controlled at 28-35℃ to replicate a uniform micro-frosted texture and form a unique frosted reflective effect. Layer B has a thickness of 0.03 mm; The thickness of layer C is 0.03 mm; The thickness of layer D is 0.03 mm; The co-extrusion temperature is controlled as follows: feeding section 190-205℃, melting section 210-225℃, die head temperature 220-230℃, production line speed 8-12m / min, four layers are extruded and shaped synchronously, and the interlayer bonding is tight without delamination.

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