Mirror PVC (polyvinyl chloride) composite film and preparation method thereof

Abstract

The invention provides a mirror PVC (polyvinyl chloride) composite film and a preparation method thereof, the PVC film is provided with a forming surface and a non-forming surface which are deviated from each other, and the PET film is arranged on the forming surface of the PVC film in a tearable manner. The mirror surface PVC film has the beneficial effects that the synergistic effect of the tearable PET film and the online optical-grade PET laminating process is innovatively adopted, so that the breakthrough improvement of the performance of the mirror surface PVC film is realized; the smooth and matt surface of the PVC film is isolated by the PET film, so that molecular migration extinction caused by contact of the smooth and matt surface is effectively inhibited, the problem of gloss attenuation after storage and transportation of a traditional product is solved, and the mirror surface effect is ensured for a long time in a conventional storage environment; meanwhile, the optical-grade PET film is arranged on the forming surface of the PVC film in an online laminating mode, so that the secondary calendering and brightening coating procedures of a mirror surface roller are omitted, calendering-laminating-rolling integrated production is realized, the mirror surface effect of a product is formed at one time, the production process is simplified, the production line speed is increased, the production efficiency is greatly improved, and the comprehensive production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of PVC composite films, and specifically relates to a mirror PVC composite film and a preparation method thereof, in particular to a mirror PVC composite film with no matting and good mirror gloss and a preparation method thereof. Background Art

[0002] In the contemporary industrial materials sector, mirrored PVC film, with its high-gloss surface, produces a near-mirror-like reflective effect, lending a visually striking appearance to a wide range of products. It is widely used in various fields, including home decor, advertising signage, automotive B-pillars, and luxury goods packaging. For example, in high-end luxury goods packaging, mirrored PVC film, with its initial gloss of >90GU (at a 60° angle of incidence), meets the stringent packaging appearance requirements of high-end brands. However, this film can experience matte and mirror failure during transportation and long-term use. Furthermore, when the roll weight exceeds 50kg / m², contact friction with the matte surface is exacerbated, resulting in a gloss decay rate exceeding 8% after three months of storage. This ultimately degrades the product's mirror finish and renders it unsatisfactory for customer use. This is despite the fact that during initial installation, the product can achieve a mirror gloss of >90GU, meeting the visual requirements of luxury goods displays. However, after six months of routine cleaning and maintenance, visible diffuse reflection streaks appeared on the surface. These micro-scratches, caused by friction from cleaning tools, and the aging of the mirrored PVC film over time, led to a decrease in the 60° incident angle measurement, ultimately significantly reducing the film's mirroring effect. For example, automakers face an even more severe challenge in B-pillar applications: Long-term use of mirrored PVC film inevitably leads to noticeable crystal defects, which in turn cause the mirroring effect to fail.

[0003] The aforementioned failures stem from the current bottleneck of the calendaring method: this method involves extruding PVC raw materials through a series of calendaring rollers at high temperatures to form a film of a certain thickness and surface quality. Finally, the surface is calendered using mirror rollers to achieve a mirrored finish. When the PVC film contacts the mirror rollers at a high temperature of 190°C, the material requires 2.4 seconds of continuous contact to achieve initial shaping. However, due to process limitations, rapid cooling is impossible upon contact with the mirror rollers. The slow cooling process prevents the polymer molecular chains from freezing quickly, resulting in an undulating surface microstructure and surface densification defects. These subwavelength-scale irregularities are the root cause of incident light scattering, making it difficult to achieve a mirrored finish. Furthermore, products produced by calendaring typically have one glossy and one matte surface. After rewinding, the glossy and matte surfaces of the product come into direct contact and rub against each other, inducing molecular migration friction under transportation pressure, exacerbating the matte problem. Patent CN106393910A discloses a mirror composite film and its preparation method. Although the application improves the surface flatness through a high-polymerization thin layer and a rare earth stabilizer, the sample prepared therefrom produces extinction after storage, accompanied by a decrease in the mirror effect.

[0004] Therefore, developing a mirror PVC film with no extinction phenomenon and good mirror gloss has become an urgent problem to be solved in this field. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present application provides a mirror-surface PVC composite film with no extinction phenomenon and good mirror gloss and a preparation method thereof.

[0006] To solve the above problems, the technical solution adopted in this application is: The invention provides a mirror PVC composite film, comprising a PVC film and a PET film. The PVC film has a forming surface and a non-forming surface that are separated from each other, and the PET film is removably arranged on the forming surface of the PVC film.

[0007] As a preferred embodiment of the present application, the PVC film comprises the following raw materials in parts by weight: 100 parts of PVC resin; 20-50 parts of polyester plasticizer; 3~8 parts of stabilizer; 1~3 parts of composite anti-ultraviolet agent; 1~3 parts of processing aid; 6-20 parts of impact modifier; 1~3 parts of brightener.

[0008] As a preferred embodiment of the present application, the PVC film comprises the following raw materials in parts by weight: 100 parts of PVC resin; 32-36 parts of polyester plasticizer; 5~6 parts of stabilizer; 1~2 parts of composite anti-ultraviolet agent; 1~3 parts of processing aid; 6-12 parts of impact modifier; 1~3 parts of brightener.

[0009] As a preference of the present application, the PVC film further comprises 4 to 10 parts by weight of a colorant.

[0010] As a preferred embodiment of the present application, the PVC film comprises the following raw materials in parts by weight: 100 parts of PVC resin; 20-50 parts of polyester plasticizer; 3~8 parts of stabilizer; 1~3 parts of composite anti-ultraviolet agent; 1~3 parts of processing aid; 6-12 parts of impact modifier; 1~3 parts of brightener; 4~10 parts of pigment.

[0011] As a preferred embodiment of the present application, the PVC film comprises the following raw materials in parts by weight: 100 parts of PVC resin; 36 parts of polyester plasticizer; 5 parts of stabilizer; 1 part of composite anti-ultraviolet agent; 2 parts of processing aid; 12 parts of impact modifier; 3 parts of brightener; 5 parts of pigment.

[0012] As a preference of the present application, the ratio of the degree of polymerization of the PVC resin to the molecular weight of the polyester plasticizer is controlled within the range of 0.2 to 1.2 to ensure a balance between plasticization efficiency and mechanical properties.

[0013] As a preference of the present application, the degree of polymerization of the PVC resin is 1300-1800.

[0014] Preferably, the polyester plasticizer is adipic acid polyester with a molecular weight of 1500-6000. This polyester plasticizer exhibits excellent oil resistance, precipitation resistance, and weather resistance. The use of a high-molecular-weight polyester plasticizer significantly improves the PVC film's compatibility with glue. The addition of a UV inhibitor significantly enhances the material's outdoor weather resistance, ensuring long-term outdoor use.

[0015] As a preference of the present application, the impact modifier is an acrylic impact modifier with a core-shell structure.

[0016] As a preference of the present application, the impact modifier is at least one of an acrylic impact modifier of model FM-40, an acrylic impact modifier of model HIA-80, and an acrylic impact modifier of model W-300A.

[0017] As a preferred embodiment of the present application, the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 4-8:2-5:1-2.

[0018] As a preference of the present application, the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 6:4:2.

[0019] As a preferred embodiment of the present application, the composite anti-ultraviolet agent is formed by mixing an ultraviolet absorber and a hindered amine light stabilizer in a mass ratio of 1:1 to 2:1.

[0020] As a preferred embodiment of the present invention, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative. The combination of the UV absorber and the hindered amine light stabilizer can produce a synergistic effect: the UV absorber blocks the initiation stage of photodegradation by shielding ultraviolet rays, while the hindered amine light stabilizer works together with the stabilizer to inhibit the oxidative chain reaction by capturing free radicals, synergistically significantly improving the light stability of the material.

[0021] As a preferred embodiment of the present application, the composite anti-UV agent is formed by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, which can produce a synergistic effect: the UV absorber blocks the photodegradation initiation stage by shielding ultraviolet rays, and the hindered amine light stabilizer inhibits the oxidation chain reaction by capturing free radicals. The two work together to significantly improve the light stability of the material.

[0022] Preferably, the brightener is silicone powder. More preferably, the silicone powder has a particle size of ≤800nm. The impact modifier's shell layer is highly compatible with the PVC resin, ensuring uniform dispersion within the system to absorb impact energy and significantly improve toughness. The brightener not only grafts onto the acrylate groups, enhancing interfacial bonding with the substrate and the impact modifier shell layer and preventing phase separation, but also forms a dense layer on the surface, reducing friction and filling microscopic defects, imparting a high gloss and smooth feel to the finished product. The two brighteners act separately within the material and on the surface, without interfering with each other and complementing each other's functions. This significantly improves product processing fluidity and demolding performance, reduces the coefficient of friction, enhances smoothness, and improves surface gloss. Furthermore, the lubricating effect of the silicone powder brightener reduces shear damage to the PVC molecular chains during processing, indirectly protecting the dispersed form of the impact modifier and promoting its dispersion, enabling it to better exert its impact resistance. The enhanced toughness of the impact modifier, combined with the improved surface wear resistance of the silicone powder, results in a smoother, more scratch-resistant, and impact-resistant surface.

[0023] As a preference of the present application, the stabilizer is a barium zinc stabilizer.

[0024] As a preference of the present application, the processing aid is PA-40.

[0025] As a preference of the present application, the colorant is carbon black.

[0026] As a preferred embodiment of the present invention, the colorant is in the form of a color paste, which can be better dispersed in PVC and improve the gloss. More preferably, the particle size of the carbon black is ≤50nm.

[0027] As a preference of the present application, the ratio of the carbon black particle size to the silicone powder particle size is controlled within a range of 1:5 to 20.

[0028] The mirror-finished PVC composite film of this invention uses PVC resin as a rigid skeleton, and polyester plasticizers bonded to PVC molecular chains via ester bonds, lowering the glass transition temperature and inhibiting migration and precipitation, maintaining long-term flexibility (elongation at break > 300%). The combination of high-polymerization resin and high-molecular-weight plasticizer can reduce the risk of thermal degradation during processing. The interaction between the components and the synergistic mechanism are as follows: PVC resin and polyester plasticizer form a dynamic network: the ester group (—COO—) of the polyester molecular chain and the chlorine atom (—Cl) of the PVC chain segment form a dipole-dipole force, reducing interchain friction. The polyester long chain and the PVC molecular chain are entangled with each other to form physical cross-linking points. The entanglement points dissociate at the processing temperature, reducing the melt viscosity; when used at room temperature, the entanglement is reconstructed to maintain flexibility and inhibit the migration of the plasticizer, thereby improving the flexibility of the PVC resin and polyester plasticizer while forming a multi-stage toughening system with the impact modifier. In addition, the hydroxyl / carboxyl group at the end of the polyester plasticizer forms a coordination bond with the stabilizer to further fix the plasticizer.

[0029] Weather resistance synergistic system formed by polyester plasticizer + composite anti-UV agent: Due to the long-term use of the product, the product's UV protection mechanism is missing and it cannot absorb ultraviolet light with a wavelength of 290-400nm. Ultraviolet radiation will directly cause the PVC molecular chain to break and generate a conjugated polyene structure, which is the root cause of the yellowing of the material. In addition, the energy of ultraviolet photons excites PVC to produce alkyl free radicals. When no anti-UV agent is added, the free radicals continue to attack the PVC main chain, triggering a chain reaction of oxidative degradation. The expansion of surface microcracks leads to enhanced diffuse reflection, resulting in a collapse of mirror reflectivity and loss of tensile strength. After ultraviolet aging, the molecular chain breaks and the material becomes brittle. Ultraviolet radiation accelerates the migration of plasticizers, weakens the cohesion of the material, and easily causes the composite layer to peel, which reduces the weather resistance and adhesion of the material, resulting in insufficient weather resistance; and plasticizers are easily precipitated at high temperatures, which accelerates material aging and causes loss of tensile strength, resulting in insufficient toughness of the product. Polyester plasticizers (molecular weight 1500~6000) maintain flexibility through migration resistance, and composite anti-UV agents absorb 290-400nm ultraviolet rays, doubly protecting the PVC molecular chains and plasticizers from photo-oxidative degradation; composite anti-UV agents can also protect the PVC molecular chains and plasticizers from degradation, which can jointly extend the product's outdoor service life, thereby overall improving the product's weather resistance and tensile strength.

[0030] The processing-performance synergistic network formed by silicone powder + impact modifier: The lubricating effect of silicone powder can reduce the breakage of PVC molecular chains caused by shear heat, indirectly protecting the dispersed form of the impact modifier, promoting its dispersion and better exerting its impact resistance. The impact modifier is an acrylate-based impact modifier with a core-shell structure. Its core layer provides high deformation capacity to absorb impact energy, and the shell layer is compatible with the PVC matrix, ensuring uniform dispersion. The core-shell structure forms a surface enrichment layer with the silicone powder. After blending with the pigment, it forms a dense layer, reducing friction and filling microscopic defects, giving the product a high gloss and smooth touch, and improving the mirror gloss. The improved toughness combined with the improved surface wear resistance of the silicone powder synergistically improves the surface gloss while enhancing the product's scratch and impact resistance. Light reflection-absorption synergistic effect formed by silicone powder + carbon black: The ratio of carbon black particle size to silicone powder particle size is controlled at 1:5~20, forming a light reflection-absorption synergistic effect.

[0031] The present invention also provides a method for preparing a mirror-finished PVC composite film, comprising the following steps: Step 1: weighing raw materials for preparing PVC film according to weight, stirring, and cooling to room temperature to obtain a premix; Step 2: plasticize the premix in an internal mixer, plasticize it again in a double-roll mill, and filter it to obtain a press material; the plasticizing temperature of the internal mixer is 165-175°C; the secondary plasticizing temperature of the double-roll mill is 170-185°C; the filter mesh size is 120-200 mesh; Step 3: The pressed material is rolled into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film to form a layer and then pressed synchronously by an embossing roller and a rubber roller to complete the online bonding of the PET film and the PVC film; Step 4: cooling, trimming and rolling to obtain a mirror PVC composite film.

[0032] As a preference of the present application, in step 3, the calendering temperature is 160°C~190°C; the five-roll speed is 10~40m / min; the stretch ratio of the take-up wheel and the embossing roller is 1~1.3; the embossing roller is a matte roller, and the temperature is 20°C~50°C; the rubber roller is 500~700 mesh, and the temperature is 20°C~40°C; the embossing pressure is 40~70N, and the unwinding tension of the PET film when superimposed with the PVC film is between 8~40N, and the thickness of the PVC film is between 0.08mm~0.3mm.

[0033] As a preference of the present application, the rubber roller is 600 mesh.

[0034] The PET film is applied to the PVC film's shaped surface, away from the embossing roller, to protect it. After winding, the matte surface of the product is separated from the glossy surface of the PVC film by the PET film. This prevents the product from matting during long-term storage and transportation. When using, simply remove the PET film from the PVC film, resulting in a mirror-like finish.

[0035] Compared with the existing technology, the beneficial effects of this application are as follows: This application innovatively uses the synergistic effect of PVC film and online optical-grade PET laminating process to achieve a breakthrough improvement in the performance of mirror-finished PVC film. The PET film isolates the matte surface of the PVC film. After winding, the PET film and PVC film are tightly bonded, effectively suppressing the molecular migration extinction caused by the contact between the matte surfaces, maintaining the mirror effect for a long time, and effectively avoiding the extinction problem. It solves the problem of gloss attenuation after storage and transportation of traditional products and solves the problem of long-term mirror effect under conventional storage conditions. At the same time, the online laminating method sets the optical-grade PET film on the forming surface of the PVC film, which not only eliminates the secondary calendering and brightening coating processes of the mirror roller, but also realizes the integrated production of "calendering-laminating-winding". The product mirror effect is formed in one go, simplifying the production process, and increasing the production line speed, greatly improving production efficiency, and reducing overall production costs. DETAILED DESCRIPTION

[0036] The following describes the implementation of the present application through specific embodiments. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0037] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0038] Furthermore, it should be understood that the one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified. It should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the presence of other devices / apparatuses before or after the combination device / apparatus, or the insertion of other devices / apparatuses between two explicitly mentioned devices / apparatuses, unless otherwise specified. Furthermore, unless otherwise specified, the numbering of each method step is merely a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be considered within the scope of the present invention.

[0039] The following describes the technical solutions of the present invention through specific examples. It should be understood that to ensure experimental uniformity, the materials used in each example were sourced from the same batch. Furthermore, the numbering of each method step serves not only as a convenient tool for identifying the method steps but also limits the order in which the examples are arranged, with the goal of verifying the feasibility of continuous recycling and replication in actual production processes.

[0040] The present application is further described below in conjunction with specific embodiments, but the protection scope of the present application is not limited thereto. Example 1

[0041] The mirror-finished PVC composite film described in this embodiment includes a PVC film and a PET film. The PVC film has a forming surface and a non-forming surface that are separated from each other. The PET film is removably arranged on the forming surface of the PVC film. The PVC film includes the following raw materials in parts by weight: 100 parts of PVC resin; 36 parts of polyester plasticizer; 5 parts of stabilizer; 1 part of composite anti-ultraviolet agent; 2 parts of processing aid; 12 parts of impact modifier; 3 parts of brightener; 5 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1300; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 6:4:2; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste.

[0042] A method for preparing a mirror-finished PVC composite film of the present invention comprises the following steps: Step 1: weigh the raw materials according to the ratio in this embodiment, add them into a high-speed mixer, stir, and then cool to room temperature to obtain a premix; Step 2: plasticizing the obtained premix by an internal mixer, plasticizing by a double-roll mill, and filtering by a filter to obtain a press material; the temperature of the double-roll mill is 175° C.; the filter mesh size of the filter is 200 mesh; Step 3: The pressed material is calendered into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film placed on the laminating frame and then synchronously pressed by an embossing roller and a rubber roller to complete the online lamination of the PET and PVC films; the calendering temperature is controlled to be 180°C for the 1# wheel, 180°C for the 2# wheel, 185°C for the 3# wheel, 181°C for the 4# wheel, and 175°C for the 5# wheel; the five-roller speed is 12m / min for the 1# wheel, 24m / min for the 2# wheel, 26m / min for the 3# wheel, and 29m / min for the 4# wheel. m / min, 5# wheel 32m / min, the draw-off wheel and main wheel stretch ratio is 1.25, the embossing roller is a matte roller, the temperature is controlled at about 30°C, the rubber wheel temperature is controlled at about 40°C, the embossing wheel and rubber wheel speed ratio is controlled at 1:1, the embossing pressure is 70N, the PET unwinding tension is 20N, the mirror PVC film thickness is 0.12mm; the PET film is a commercially available optical grade film with a PET film thickness of 50μm and a surface gloss of 180G·U. Step 4: cooling, trimming and rolling to obtain the mirror PVC composite film.

[0043] The surface hardness of the product was tested using a Shore A durometer, and the thickness was measured using a non-contact measurement method. Product performance testing: The surface gloss of the material was tested in accordance with the standard GB / T 8807-1988, Test Method for Mirror Gloss of Plastics, and the overall performance of the product was tested. Tensile strength was tested using a universal tensile testing machine in accordance with the industry standard YBB00112003-2015, "Determination of Tensile Properties of Polyvinyl Chloride Film." The elongation at break was tested using a universal material testing machine, primarily in accordance with the national standard (GB / T1040.3-2006, "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Thin Plastics and Sheets"). Before testing the mirror PVC film, the PET was torn off to test the PVC film's performance. The results are shown in Table 1. Example 2

[0044] The difference between this embodiment and embodiment 1 is that the amount of polyester plasticizer used in the formula is different, that is, the amount of polyester plasticizer used is 20 parts. The other process conditions are the same. Example 3

[0045] The difference between this embodiment and embodiment 1 is that the amount of polyester plasticizer used in the formula is different, that is, the amount of polyester plasticizer used is 50 parts. The other process conditions are the same. Example 4

[0046] The difference between this embodiment and embodiment 1 is that the degree of polymerization of the PVC resin and the molecular weight of the polyester plasticizer are different, that is, the degree of polymerization of the PVC resin is 1800 and the molecular weight of the polyester plasticizer is 1500. The other process conditions are the same. Example 5

[0047] The mirror-finished PVC composite film described in this embodiment includes a PVC film and a PET film. The PVC film has a forming surface and a non-forming surface that are separated from each other. The PET film is removably arranged on the forming surface of the PVC film. The PVC film includes the following raw materials in parts by weight: 100 parts of PVC resin; 32 parts of polyester plasticizer; 6 parts of stabilizer; 2 parts of composite anti-ultraviolet agent; 2 parts of processing aid; 10 parts of impact modifier; 2 parts of brightener; 5 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1500; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 4:4:2; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste.

[0048] A method for preparing a mirror-finished PVC composite film of the present invention comprises the following steps: Step 1: weigh the raw materials according to the ratio in this embodiment, add them into a high-speed mixer, stir, and then cool to room temperature to obtain a premix; Step 2: plasticizing the obtained premix by an internal mixer, plasticizing by a double-roll mill, and filtering by a filter to obtain a press material; the temperature of the double-roll mill is 180° C.; the filter mesh size of the filter is 160 mesh; Step 3: The pressed material is calendered into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film placed on the laminating frame and then synchronously pressed by an embossing roller and a rubber roller to complete the online lamination of the PET and PVC films; the calendering temperature is controlled to be 185°C for the 1# wheel, 185°C for the 2# wheel, 190°C for the 3# wheel, 183°C for the 4# wheel, and 176°C for the 5# wheel; the five-roller speed is 10m / min for the 1# wheel, 20m / min for the 2# wheel, 24m / min for the 3# wheel, and 28m / min for the 4# wheel. m / min, the 5# wheel is 30m / min, the stretch ratio between the take-up wheel and the main wheel is 1.1, the embossing roller is a matte roller, the temperature is controlled at around 30°C, the temperature of the rubber wheel is controlled at around 40°C, the speed ratio between the embossing wheel and the rubber wheel is controlled at 1:0.8, the embossing pressure is 70N, the PET unwinding tension is 20N, and the mirror PVC film has a thickness of 0.15mm; the five-roll calender has five pairs of rollers, which are named 1# wheel, 2# wheel, 3# wheel, 4# wheel, and 5# wheel in the conveying direction; the PET film is a commercially available optical grade film with a thickness of 50μm and a surface gloss of 180G·U. Step 5: cooling, trimming and rolling to obtain the mirror PVC composite film. Example 6

[0049] The mirror-finished PVC composite film described in this embodiment includes a PVC film and a PET film. The PVC film has a forming surface and a non-forming surface that are separated from each other. The PET film is removably arranged on the forming surface of the PVC film. The PVC film includes the following raw materials in parts by weight: 100 parts of PVC resin; 36 parts of polyester plasticizer; 5 parts of stabilizer; 2 parts of composite anti-ultraviolet agent; 1 part of processing aid; 12 parts of impact modifier; 2 parts of brightener; 5 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1800; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 6:4:2; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste.

[0050] The present embodiment provides a method for preparing a mirror-finished PVC composite film, comprising the following steps: Step 1: weigh the raw materials according to the ratio in this embodiment, add them into a high-speed mixer, stir, and then cool to room temperature to obtain a premix; Step 2: plasticizing the obtained premix by an internal mixer, plasticizing by a double-roll mill, and filtering by a filter to obtain a press material; the temperature of the double-roll mill is 185° C.; the filter mesh size of the filter is 160 mesh; Step 3: The pressed material is calendered into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film placed on the laminating frame and then synchronously pressed by an embossing roller and a rubber roller to complete the online lamination of the PET and PVC films; the calendering temperature is controlled to be 180°C for the 1# wheel, 180°C for the 2# wheel, 185°C for the 3# wheel, 181°C for the 4# wheel, and 175°C for the 5# wheel; the five-roller speed is 14m / min for the 1# wheel, 28m / min for the 2# wheel, 34m / min for the 3# wheel, and 38m / min for the 4# wheel. m / min, 5# wheel 40m / min, the stretch ratio between the take-up wheel and the main wheel is 1.3, the embossing roller is a matte roller, the temperature is controlled at about 30°C, the temperature of the rubber wheel is controlled at about 40°C, the speed ratio between the embossing wheel and the rubber wheel is controlled at 1:1, the embossing pressure is 70N, the PET unwinding tension is 20N, the mirror PVC film has a thickness of 0.08mm; the PET film is a commercially available optical grade film with a thickness of 30μm and a surface gloss of 180G·U. Step 5: cooling, trimming and rolling to obtain the mirror PVC composite film. Example 7

[0051] The mirror-finished PVC composite film described in this embodiment includes a PVC film and a PET film. The PVC film has a forming surface and a non-forming surface that are separated from each other. The PET film is removably arranged on the forming surface of the PVC film. The PVC film includes the following raw materials in parts by weight: 100 parts of PVC resin; 32 parts of polyester plasticizer; 6 parts of stabilizer; 1 part of composite anti-ultraviolet agent; 2 parts of processing aid; 8 parts of impact modifier; 1 part of brightener; 5 parts of pigment; Among them, the PVC resin has a polymerization degree of 1500; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 4:3:1; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste.

[0052] The present embodiment provides a method for preparing a mirror-finished PVC composite film, comprising the following steps: Step 1: weigh the raw materials according to the ratio in this embodiment, add them into a high-speed mixer, stir, and then cool to room temperature to obtain a premix; Step 2: plasticizing the obtained premix by an internal mixer, plasticizing by a double-roll mill, and filtering by a filter to obtain a press material; the temperature of the double-roll mill is 185° C.; the filter mesh size of the filter is 200 mesh; Step 3: The pressed material is calendered into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film placed on the laminating frame and then synchronously pressed by an embossing roller and a rubber roller to complete the online lamination of the PET and PVC films; the calendering temperature is controlled to be 180°C for the 1# wheel, 180°C for the 2# wheel, 185°C for the 3# wheel, 181°C for the 4# wheel, and 175°C for the 5# wheel; the five-roller speed is 10m / min for the 1# wheel, 18m / min for the 2# wheel, 24m / min for the 3# wheel, and 26m / min for the 4# wheel. m / min, 5# wheel 30m / min, the stretch ratio between the take-up wheel and the main wheel is 1.15, the embossing roller is a matte roller, the temperature is controlled at about 30°C, the temperature of the rubber wheel is controlled at about 30°C, the speed ratio between the embossing wheel and the rubber wheel is controlled at 1:0.9, the embossing pressure is 70N, the PET unwinding tension is 30N, the mirror PVC film has a thickness of 0.2mm; the PET film is a commercially available optical grade film with a thickness of 60μm and a surface gloss of 200G·U; Step 5: cooling, trimming and rolling to obtain the mirror PVC composite film. Example 8

[0053] The difference between this embodiment and embodiment 1 is that the formula is different, and the rest of the processes are the same.

[0054] Specifically, the mirror-finished PVC composite film described in this embodiment includes the following raw materials in parts by weight: 100 parts of PVC resin; 20 parts of polyester plasticizer; 3 parts of stabilizer; 1 part of composite anti-ultraviolet agent; 1 part of processing aid; 6 parts of impact modifier; 1 part of brightener; 4 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1300; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 3:2:1; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste. Example 9

[0055] The difference between this embodiment and embodiment 1 is that the formula is different, and the rest of the processes are the same.

[0056] Specifically, the mirror-finished PVC composite film described in this embodiment includes the following raw materials in parts by weight: 100 parts of PVC resin; 50 parts of polyester plasticizer; 8 parts of stabilizer; 3 parts of composite anti-ultraviolet agent; 3 parts of processing aid; 20 parts of impact modifier; 3 parts of brightener; 10 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1300; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 5:4:1; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste. Example 10

[0057] This embodiment differs from Example 1 in that the composite anti-UV agent is formulated differently. The composite anti-UV agent is composed of a UV absorber and a hindered amine light stabilizer in a mass ratio of 2:1. The UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative. The remaining processes are identical. Example 11

[0058] The difference between this embodiment and embodiment 1 is that the impact modifier is different, and the impact modifier in this embodiment is HIA-80. The rest of the processes are the same.

[0059] Comparative Example 1 The difference between this comparative example and Example 1 is that no PET film is provided, and the other processes are the same.

[0060] Specifically, the PVC film described in this comparative example includes the following raw materials in parts by weight: 100 parts of PVC resin; 36 parts of polyester plasticizer; 5 parts of stabilizer; 1 part of composite anti-ultraviolet agent; 2 parts of processing aid; 12 parts of impact modifier; 3 parts of brightener; 5 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1300; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 6:4:2; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste.

[0061] This comparative example provides a method for preparing a PVC film, comprising the following steps: The raw materials were weighed according to the ratio in this comparative example, added into a high-speed mixer, stirred, and then cooled to room temperature to obtain a premix; The obtained premix was plasticized in an internal mixer, plasticized in a double-roll mill, and filtered in a filter to obtain a press material; the temperature of the double-roll mill was 175° C.; the filter mesh size was 200 mesh; The pressed material is calendered by a five-roll calender and drawn out by a take-up roller. The drawn-out PVC film is synchronously pressed by an embossing roller and a rubber roller to obtain a product. The calendering temperature is controlled at 180°C for the 1# roller, 180°C for the 2# roller, 185°C for the 3# roller, 181°C for the 4# roller, and 175°C for the 5# roller. The speeds of the five rollers are 12m / min for the 1# roller, 24m / min for the 2# roller, 26m / min for the 3# roller, 29m / min for the 4# roller, and 32m / min for the 5# roller. The stretching ratio between the take-up roller and the main roller is 1.25. The embossing roller is a mirror roller, the temperature of which is controlled at around 30°C, the temperature of the rubber roller is controlled at around 40°C, the speed ratio of the embossing roller to the rubber roller is controlled at 1:1, the embossing pressure is 70N, and the thickness of the mirror PVC film is 0.12mm. Step 5: cooling, trimming and rolling to obtain the PVC film.

[0062] Comparative Example 2 The difference between this comparative example and Example 1 is that no brightener is added in the formula, ordinary grade PET film is selected as the PET film, and the other processes are the same.

[0063] 100 parts of PVC resin; 32 parts of polyester plasticizer; 6 parts of stabilizer; 2 parts of composite anti-ultraviolet agent; 2 parts of processing aid; 10 parts of impact modifier; 5 parts of pigment; Among them, the PVC resin has a degree of polymerization of 1500; the polyester plasticizer is adipic acid polyester with a molecular weight of 6000; the stabilizer is a barium zinc stabilizer; the composite anti-UV agent is prepared by compounding a UV absorber and a hindered amine light stabilizer in a mass ratio of 1:1, the UV absorber is a benzophenone compound, and the hindered amine light stabilizer is a low-alkalinity tetramethylpiperidine derivative; the impact modifier is prepared by compounding FM-40, HIA-80, and W-300A in a mass ratio of 4:4:2; the processing aid is PA-40; the brightener is silicone powder with a particle size of ≤800nm; and the colorant is a black color paste.

[0064] This comparative example provides a method for preparing a PVC film, comprising the following steps: Step 1: weigh the raw materials according to the ratio in this comparative example, add them into a high-speed mixer, stir, and then cool to room temperature to obtain a premix; Step 2: plasticizing the obtained premix by an internal mixer, plasticizing it again by a double-roll mill, and filtering it by a filter to obtain a press material; the temperature of the double-roll mill is 175° C.; the filter mesh size of the filter is 200 mesh; Step 3: The pressed material is calendered into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film and then synchronously pressed by an embossing roller and a rubber roller to complete the online bonding of the PET film and the PVC film; the calendering temperature is controlled as follows: 1# wheel 180°C, 2# wheel 180°C, 3# wheel 185°C, 4# wheel 181°C, 5# wheel 175°C, and the five-roll roller speed is 1# wheel 12m / min, 2# wheel 24m / min, 3# wheel 26m / min, 4# wheel 29 m / min, 5# wheel 32m / min, the draw ratio between the take-up wheel and the main wheel is 1.25, the embossing roller is a matte roller, the temperature is controlled at about 30°C, the temperature of the rubber wheel is controlled at about 40°C, the speed ratio between the embossing wheel and the rubber wheel is controlled at 1:1, the embossing pressure is 70N, the PET film unwinding tension is 20N, the PVC film thickness is 0.12mm; the PET film is a commercially available ordinary grade film, the PET film thickness is 50μm, and the surface gloss is 120G·U. Step 4: cooling, trimming and rolling to obtain the mirror PVC composite film.

[0065] Comparative Example 3 The difference between this comparative example and Example 1 is that the impact modifier is nitrile rubber, and the other processes are the same.

[0066] Comparative Example 4 The difference between this comparative example and Example 1 is that nano talc powder is used instead of silicone powder, and the other processes are the same.

[0067] Comparative Example 5 The difference between this comparative example and Example 1 is that the degree of polymerization of the PVC resin is 1000, and the polyester plasticizer is adipic acid polyester with a molecular weight of 8000, that is, the ratio of the degree of polymerization of the PVC resin to the molecular weight of the polyester plasticizer is 0.125. The rest of the processes are the same.

[0068] Comparative Example 6 The difference between this comparative example and Example 1 is that the PET film is replaced by a PVDC film. The rest of the processes are the same.

[0069] The performance testing methods of the mirror-finished PVC composite films prepared in Examples 2 to 11 and the PVC films prepared in Comparative Examples 1 to 6 are the same as those in Example 1 and will not be repeated here.

[0070] According to the GB / T18244-2022 standard, the mirror-finished PVC composite films prepared in Examples 1, 8, and 10, and the product prepared in Comparative Example 1 were subjected to an ultraviolet accelerated aging test, and the gloss of the products was tested according to the standard GB / T 8807-1988 plastic mirror gloss test method. The products prepared in Examples 1, 8, and 10 had a smooth surface gloss (60°) of 87 G·U, 88 G·U, and 91 G·U, respectively, and showed no cracking or powdering. However, the product in Comparative Example 1 had a smooth surface gloss (60°) of 73 G·U and showed powdering and cracking. This indicates that the products prepared in Examples 1, 8, and 10 have better mirror effects, and Example 10 has the best mirror effect, meeting the requirements for long-term outdoor use.

[0071] Table 1 Product performance test indicators , As can be seen from Table 1, compared with Comparative Example 5, Example 1 exhibits a significantly lower PVC degree of polymerization than the polyester plasticizer molecular weight. The ratio of PVC resin degree of polymerization to polyester plasticizer molecular weight is 0.125, which can make it difficult for the plasticizer molecules to disperse evenly within the PVC segments, leading to localized aggregation and reduced compatibility. This reduces the toughness of the product and prevents a good mirror finish. When the ratio of PVC degree of polymerization to polyester plasticizer molecular weight is within the range of 0.2 to 1.2, low ratios result in insufficient molecular chain entanglement due to the large plasticizer molecular weight, resulting in limited improvement in toughness. High ratios, however, result in easier insertion between PVC chains due to the small plasticizer molecular weight, significantly improving elongation at break and impact strength. Compared with Examples 2 and 3, Example 1 shows significant improvements in elongation at break and impact strength as the amount of polyester plasticizer increases. The 20° gloss values ​​for Examples 1-11 range from 81-88 G·U, and the 60° gloss values ​​range from 90-95 G·U, significantly exceeding those of the comparative examples (55-84 G·U at 20° and 82-91 G·U at 60°). While the 60° angle is suitable for all materials, the 20° angle is specifically designed for high-gloss materials (i.e., 60° gloss values ​​exceeding 70 units). The 60° values ​​for the examples all exceed 90 G·U, placing them in the high-gloss range. Therefore, 20° measurements more accurately capture their specular details. Examples 1, 8, and 11 had the highest 20° gloss, at 88 G·U. Examples 1, 8, and 10 had the highest 60° gloss, at 95 G·U. This indicates that Examples 1 and 5 achieved the best mirror finish. Comparative Example 1, however, had a 20° gloss of only 55 G·U and a 60° gloss of 82 G·U, both below the critical threshold for a mirror finish (60° gloss > 70 units), failing to achieve a mirror finish. Examples 1-11, however, exhibited high surface hardness and strong scratch resistance. The surface hardness of Examples 1-11 (68-80 Shore A) was generally higher than that of the Comparative Example (65-70 Shore A), with Example 8 achieving the highest hardness (80 Shore A), indicating stronger scratch resistance. The tensile strength (28.65-35.58 MPa) and elongation at break (232.11-370.11%) of Examples 1-11 are generally better than those of the comparative example (26.89-30.03 MPa and 239.22-298.77%). Example 9 has the highest elongation at break (370.11%), showing better flexibility.

[0072] Taking all factors into consideration, the formulations of Examples 1 to 11 all achieved a mirror effect, and their comprehensive performance (gloss, hardness, and strength) was significantly ahead of the comparative example; Example 1, Example 8, and Example 10 all performed better in gloss, and were well-balanced in hardness and tensile strength, and had a better mirror effect.

[0073] The above examples are for the purpose of illustrating the embodiments disclosed in the present application and are not to be construed as limiting the present application. In addition, the various modifications listed herein and the variations of the methods and compositions in the invention will be apparent to those skilled in the art without departing from the scope and spirit of the present application. Although the present application has been specifically described with reference to various specific preferred embodiments of the present application, it should be understood that the present application should not be limited to these specific embodiments. In fact, various modifications apparent to those skilled in the art as described above to obtain the invention will fall within the scope of the present application.

Claims

1. A mirror PVC composite film, characterized in that: The invention comprises a PVC film and a PET film. The PVC film has a forming surface and a non-forming surface which are separated from each other. The PET film is removably arranged on the forming surface of the PVC film.

2. The mirror surface PVC composite film according to claim 1, characterized in that: The PET film is an optical-grade film with a thickness of 20 μm to 60 μm and a surface gloss greater than 180 G·U.

3. The mirror surface PVC composite film according to claim 1, characterized in that: The PVC film comprises the following raw materials in parts by weight: 100 parts of PVC resin; 20-50 parts of polyester plasticizer; 3~8 parts of stabilizer; 1~3 parts of composite anti-ultraviolet agent; 1~3 parts of processing aid; 6-20 parts of impact modifier; 1~3 parts of brightener.

4. The mirror surface PVC composite film according to claim 2, characterized in that: include: 100 parts of PVC resin; 32-36 parts of polyester plasticizer; 5~6 parts of stabilizer; 1~2 parts of composite anti-ultraviolet agent; 1~3 parts of processing aid; 6-12 parts of impact modifier; 1~3 parts of brightener.

5. The mirror surface PVC composite film according to claim 3, characterized in that: The ratio of the polymerization degree of the PVC resin to the molecular weight of the polyester plasticizer is controlled within the range of 0.2 to 1.

2.

6. The mirror-finished PVC composite film according to claim 3, characterized in that: The polymerization degree of the PVC resin is 1300-1800; the polyester plasticizer is adipic acid polyester with a molecular weight of 1500-6000.

7. The mirror-finished PVC composite film according to claim 3, characterized in that: The impact modifier is an acrylic ester impact modifier with a core-shell structure; and the brightener is silicone powder.

8. The mirror-finished PVC composite film according to claim 3, characterized in that: The composite anti-ultraviolet agent is a mixture of an ultraviolet absorber and a hindered amine light stabilizer in a mass ratio of 1:1 to 2:

1.

9. A method for preparing the mirror-finished PVC composite film according to any one of claims 1 to 8, comprising the following steps: Step 1: weighing raw materials for preparing PVC film according to weight, stirring, and cooling to room temperature to obtain a premix; Step 2: plasticize the premix in an internal mixer, plasticize it again in a double-roll mill, and filter it to obtain a press material; the plasticizing temperature of the internal mixer is 165-175°C; the secondary plasticizing temperature of the double-roll mill is 170-185°C; the filter mesh size is 120-200 mesh; Step 3: The pressed material is calendered into a PVC film by a five-roll calender and then drawn out by a take-up wheel. The formed surface of the drawn PVC film is superimposed on the PET film and then pressed synchronously by an embossing roller and a rubber roller to complete the online bonding of the PET film and the PVC film; Step 4: cooling, trimming and rolling to obtain a mirror PVC composite film.

10. The preparation method according to claim 9, characterized in that In step 3, the calendering temperature is 160°C to 190°C; the five-roll speed is 10-40 m / min; the stretch ratio of the take-up wheel to the embossing roller is 1-1.3; the embossing roller is a matte roller, and the temperature is 20°C to 50°C; the rubber roller is 500-700 mesh, and the temperature is 20°C to 40°C; the embossing pressure is 40-70N, and the unwinding tension of the PET film when superimposed with the PVC film is between 8-40N, and the thickness of the PVC film is between 0.08mm and 0.3mm.