A light-diffusing polyester reflective film and preparation method thereof

Abstract

The present invention provides a light-diffusing polyester reflective film and a preparation method thereof, and relates to the technical field of light-diffusing polyester reflective film. The light-diffusing polyester reflective film is an ABA three-layer co-extruded structure; wherein the material of the A layer includes the following components: polyethylene terephthalate slices, inorganic fillers, heat stabilizers, light stabilizers, antistatic agents, and hydrolysis resistant agents; the material of the B layer includes the following components: polyethylene terephthalate slices, functional foaming masterbatch, high-melting-point polyolefins, inorganic fillers, toughening agents, and heat stabilizers. The light-diffusing polyester reflective film provided by the present invention reduces the production cost by introducing low-melting-point polyolefins modified by silicone resin into the PET polyester core layer, and compounding with high-melting-point polyolefins, and utilizing the synergistic effect between the components, so that the prepared light-diffusing polyester reflective film has good reflectivity and light diffusion performance.

Description

Technical Field

[0001] The invention relates to the technical field of light-diffusing polyester reflective films, and in particular to a light-diffusing polyester reflective film and a preparation method thereof. Background Art

[0002] As the mainstream technology in the field of optoelectronic information display, the market application of liquid crystal display technology is expanding day by day. Liquid crystal displays can display text and images, which is mainly due to the light source of the backlight module modulating light by controlling the liquid crystal electric field to achieve the display effect. The quality of the backlight module is a factor that determines the key performance of the liquid crystal display system, such as brightness, uniformity, chromaticity and energy consumption, which in turn affects the visual experience. The backlight module is composed of multiple components, including light source, reflective film, diffusion film, brightening film and light guide plate. Among them, the reflective film is located at the bottom of the module. Its core function is to reflect the light passing through the light guide plate back to the light guide plate to reduce light loss and energy consumption, while improving the brightness and light saturation of the display panel.

[0003] The reflective films currently produced on the market usually use polyethylene terephthalate (PET) or polycarbonate (PC) as the substrate, and are formed by adding inorganic filler particles or incompatible polymer particles and stretching them. During the stretching process, fine bubbles are formed between the incompatible polymer particles or inorganic particles and the polyester. These fine bubbles can play a role in light scattering, thereby preparing a white reflective film with high reflectivity. In addition, in the backlight source of a liquid crystal display, it is necessary to atomize a point light source or a line light source into a uniform surface light source to improve the brightness and brightness uniformity of the liquid crystal display panel. This requires that the reflective film not only has a high reflectivity, but also has good light diffusion performance to achieve uniform diffuse reflection of light.

[0004] However, in the prior art, in order to manufacture a film with high reflectivity, it is often necessary to rely on the use of highly heat-resistant polyolefins alone. Although this method can ensure the optical properties of the film, its high cost limits its economic feasibility in large-scale production. In order to reduce costs, some manufacturers use low-melting-point polyolefins such as polypropylene and polyethylene as foaming materials, but these materials have poor heat resistance, resulting in cell collapse, which not only reduces the reflectivity, but also changes the scattering properties of light, thereby affecting the light diffusion effect. Therefore, how to take into account the production cost and reflectivity of the light-diffusing polyester reflective film while improving the light diffusion of the light-diffusing polyester reflective film to achieve uniform atomization of the backlight source and improve the brightness and brightness uniformity of the liquid crystal display panel is a key technical difficulty. Summary of the invention

[0005] In order to solve the problem that the prior art cannot take into account both the production cost and the reflectivity of the light-diffusing polyester reflective film and improve the light diffusion property of the light-diffusing polyester reflective film, the present invention discloses a light-diffusing polyester reflective film. By introducing a low-cost low-melting-point polyolefin as an incompatible resin into the PET polyester core layer and compounding it with a high-melting-point polyolefin, the production cost is reduced while the prepared light-diffusing polyester reflective film has good reflectivity. In addition, the present invention uses an organic silicone resin to modify the low-melting-point polyolefin, which not only improves the heat resistance of the light-diffusing polyester reflective film, but also because the organic silicone resin has good dispersibility in polyester, the light is continuously refracted, reflected and scattered in different resins to form a uniform light path, thereby improving the light diffusion property.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A light-diffusing polyester reflective film, wherein the light-diffusing polyester reflective film is an ABA three-layer co-extruded structure;

[0008] The materials of the A layer include the following components in parts by weight:

[0009] 40-80 pieces of polyethylene terephthalate slices;

[0010] 5-30 parts of inorganic filler;

[0011] Heat stabilizer 0.1-1 part;

[0012] Light stabilizer 1-5 parts;

[0013] Antistatic agent 1-10 parts;

[0014] 1-10 parts of hydrolysis resistance agent;

[0015] The materials of the B layer include the following components in parts by weight:

[0016] 40-80 pieces of polyethylene terephthalate slices;

[0017] Functional foaming masterbatch 1-30 parts;

[0018] 5-35 parts of high melting point polyolefin;

[0019] 10-30 parts of inorganic filler;

[0020] Toughener 0.1-2 parts;

[0021] Heat stabilizer 0.1-2 parts;

[0022] The functional foaming masterbatch is obtained by modifying low melting point polyolefin with organic silicone resin.

[0023] Optionally, the functional foaming masterbatch in layer B is prepared according to the following method:

[0024] Deionized water, ethanol and a compatibilizer are added to a container and stirred evenly, then a low-melting-point polyolefin is added and stirred continuously, and a pretreated low-melting-point polyolefin is obtained after drying; the low-melting-point polyolefin is then mixed evenly with an organosilicon resin and added to an extruder to obtain a functional foaming masterbatch.

[0025] Optionally, the mass ratio of the deionized water, ethanol, compatibilizer, low melting point polyolefin and silicone resin is (1-10): (40-70): (10-30): (50-80): (10-20).

[0026] Optionally, the silicone resin is at least one of polymethyl silicone resin, polyethyl silicone resin, polyphenyl silicone resin, polymethylphenyl silicone resin, and vinyl silicone resin.

[0027] Optionally, the compatibilizer is at least one of vinyl trichlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, phenylaminopropyl trimethoxysiloxane, γ-aminopropyl triethoxysiloxane, acrylate propyl trimethoxysiloxane, and γ-methacryloxypropyl trimethoxysiloxane.

[0028] Optionally, the low melting point polyolefin is at least one of polyethylene, polypropylene, polymethyl methacrylate, polybutylene, ethylene-vinyl acetate copolymer, and ethylene-acrylate copolymer.

[0029] Optionally, the polyethylene is at least one of high-density polyethylene HDPE, linear low-density polyethylene LLDPE, and low-density polyethylene LDPE.

[0030] Optionally, the high melting point polyolefin in layer B is at least one of poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, polystyrene, polymethylstyrene, polydimethylstyrene, polyvinyl fluoride, and cycloolefin copolymer.

[0031] Optionally, the anti-hydrolysis agent in layer A is at least one of monomeric carbodiimide, polymeric carbodiimide, bisphenol A diglycidyl ether, tetrakis(phenylglycidyl ether)ethane, and trimethoxy[3-(glycidyl ether)propyl]silane.

[0032] Another object of the present invention is to provide a method for preparing the light-diffusing polyester reflective film as described above, comprising the following steps:

[0033] S1: The raw materials of layer B are mixed evenly according to the ratio and added into the extruder to obtain mixed masterbatch of layer B;

[0034] S2: The raw materials of layer A are mixed evenly according to the ratio and added into the extruder to obtain mixed masterbatch of layer A;

[0035] S3: The B layer mixed masterbatch and the A layer mixed masterbatch are respectively sent to the main extruder and the auxiliary extruder for melt extrusion, cast film, and then longitudinal stretching, transverse stretching, shaping, cooling, pulling, and winding to obtain a light diffusion polyester reflective film.

[0036] The present invention has the following beneficial effects:

[0037] The light-diffusing polyester reflective film provided by the present invention introduces low-cost low-melting-point polyolefin as an incompatible resin into the PET polyester core layer, and through compounding with high-melting-point polyolefin, as well as the synergistic effect between the components, the prepared light-diffusing polyester reflective film has good reflectivity, mechanical properties and dimensional stability, while greatly reducing the production cost; in addition, the present invention uses silicone resin to modify the low-melting-point polyolefin, which not only improves the heat resistance of the light-diffusing polyester reflective film, but also because the silicone resin has good dispersibility in polyester, the light is continuously refracted, reflected and scattered in different resins to form a uniform light path, thereby improving the light diffusion performance of the light-diffusing polyester reflective film. DETAILED DESCRIPTION

[0038] The present invention is now further described in detail. The embodiments described below are exemplary and intended to be used to explain the present invention, but cannot be understood as limiting the present invention. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0039] In order to solve the problem that the prior art cannot take into account both the production cost and reflectivity of the light-diffusing polyester reflective film and improve the light diffusion property of the light-diffusing polyester reflective film, the present invention provides a light-diffusing polyester reflective film, and the light-diffusing polyester reflective film is an ABA three-layer co-extruded structure;

[0040] The materials of layer A include the following components by weight:

[0041] 40-80 pieces of polyethylene terephthalate slices;

[0042] 5-30 parts of inorganic filler;

[0043] Heat stabilizer 0.1-1 part;

[0044] Light stabilizer 1-5 parts;

[0045] Antistatic agent 1-10 parts;

[0046] 1-10 parts of hydrolysis resistance agent;

[0047] The materials of layer B include the following components in parts by weight:

[0048] ;

[0049]

[0050] The functional foaming masterbatch is obtained by modifying low melting point polyolefin with organic silicone resin.

[0051] The light-diffusing polyester reflective film provided by the present invention introduces low-cost low-melting-point polyolefin as an incompatible resin into the PET polyester core layer, and through compounding with high-melting-point polyolefin, as well as the synergistic effect between the components, the prepared light-diffusing polyester reflective film has good reflectivity, mechanical properties and dimensional stability, while greatly reducing the production cost; in addition, the present invention uses silicone resin to modify the low-melting-point polyolefin, which not only improves the heat resistance of the light-diffusing polyester reflective film, but also because the silicone resin has good dispersibility in polyester, the light is continuously refracted, reflected and scattered in different resins to form a uniform light path, thereby improving the light diffusion performance of the light-diffusing polyester reflective film.

[0052] The mechanism of using silicone resin to modify low melting point polyolefin is: with the assistance of compatibilizer, the principle of similar compatibility is used to achieve excellent interface interaction between silicone resin and polyolefin in a high temperature molten state. The pore structure formed by the functional foaming masterbatch prepared in this way is stable, not easy to collapse, and densely distributed; at the same time, based on the excellent dispersibility of silicone resin in polyester and the difference in refractive index with the polyester matrix, it promotes the continuous refraction, reflection and scattering of light between different resins, forming a uniform light path, thereby significantly improving the light diffusion performance of the polyester reflective film.

[0053] Specifically, in order to further improve the comprehensive performance of the light-diffusing polyester reflective film of the present invention, the functional foaming masterbatch in the B layer of the present invention is preferably prepared according to the following method:

[0054] Deionized water, ethanol and a compatibilizer are added to a container and stirred evenly, then a low-melting-point polyolefin is added and stirred continuously, and a pretreated low-melting-point polyolefin is obtained after drying; the low-melting-point polyolefin is then mixed evenly with an organosilicon resin and added to an extruder to obtain a functional foaming masterbatch.

[0055] Furthermore, the present invention preferably has a mass ratio of deionized water, ethanol, compatibilizer, low melting point polyolefin and silicone resin of (1-10): (40-70): (10-30): (50-80): (10-20).

[0056] By introducing low-cost low-melting-point polyolefin as an incompatible resin into the core layer PET polyester, the preparation process is simplified while the overall production cost is effectively reduced; and by compounding it with high-melting-point polyolefin and utilizing the synergistic effect between the components, the prepared film maintains good reflectivity, mechanical properties and dimensional stability; at the same time, the introduction of silicone resin not only improves the heat resistance of low-melting-point polyolefin, but also achieves good interface interaction with polyolefin, so that the bubbles formed by the prepared functional foaming masterbatch have a stable structure, are not easy to collapse, and are densely distributed, and can maintain the stability of the material during high-temperature processing; in addition, the excellent dispersibility of silicone resin in polyester enables light to produce continuous refraction, reflection and scattering effects when passing through different resins, thereby forming a uniform light path and significantly improving the light diffusion performance of the film.

[0057] The silicone resin has a three-dimensional cross-linked network molecular structure, has excellent heat resistance and dispersion properties, and can make the base material, i.e. PET, have light diffusion properties with high haze and high light transmittance; the preferred silicone resin of the present invention is at least one of polymethyl silicone resin, polyethyl silicone resin, polyphenyl silicone resin, polymethylphenyl silicone resin, and vinyl silicone resin.

[0058] In order to enhance the adhesion and compatibility between the components, the preferred compatibilizer of the present invention is at least one of vinyl trichlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, phenyl aminopropyl trimethoxysiloxane, γ-aminopropyl triethoxysiloxane, acrylate propyl trimethoxysiloxane, and γ-methacryloxypropyl trimethoxysiloxane.

[0059] In the present invention, the low melting point polyolefin is preferably at least one of polyethylene, polypropylene, polymethyl methacrylate, polybutylene, ethylene-vinyl acetate copolymer, and ethylene-acrylate copolymer.

[0060] It is preferred that the high melting point polyolefin in the B layer is at least one of poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, polystyrene, polymethylstyrene, polydimethylstyrene, polyvinyl fluoride and cycloolefin copolymer.

[0061] The light stabilizer can effectively absorb ultraviolet rays and prevent the material from being degraded due to ultraviolet radiation, thereby extending the service life of the light-diffusing polyester reflective film; in the present invention, the light stabilizer in the B layer is preferably at least one of the ultraviolet absorbers triazines, benzotriazoles, benzophenones and hindered amines.

[0062] In order to ensure that the light-diffusing polyester reflective film of the present invention has good antistatic properties in various application environments and improve the practicality and user satisfaction of the product; the antistatic agent in the B layer of the present invention is preferably at least one of stearyl trimethyl quaternary ammonium hydrochloride, stearamidopropyl hydroxyethyl quaternary ammonium nitrate, stearyl dimethyl amyl ammonium chloride, trihydroxyethyl methyl quaternary ammonium methyl sulfate, stearamidopropyl dimethyl-β-hydroxyethyl ammonium dihydrogen phosphate, quaternary ammonium carboxylic acid inner salt, and imidazoline metal salt.

[0063] The preferred anti-hydrolysis agent in the A layer of the present invention is at least one of monomeric carbodiimide, polymeric carbodiimide, bisphenol A diglycidyl ether, tetrakis(phenylglycidyl ether)ethane, and trimethoxy[3-(glycidyl ether)propyl]silane; these anti-hydrolysis agents have high chemical stability and good compatibility with the polyester substrate, which can ensure uniform dispersion during mixing and processing, thereby improving product performance.

[0064] In order to improve the toughness of the polyester film and make it less likely to break when impacted or stretched, the toughening agent in the A layer of the present invention is preferably at least one of glycidyl methacrylate (GMA) grafted hydrogenated styrene-butadiene copolymer (SEBS), maleic anhydride (MAH) grafted SEBS, ethylene-octene grafted copolymer (POE) grafted MAH, POE grafted GMA, and ethylene-butyl acrylate copolymer (EBA) grafted GMA.

[0065] The inorganic filler of the present invention is preferably at least one of barium sulfate, titanium dioxide, silicon dioxide, calcium carbonate, magnesium carbonate, talc, mica and montmorillonite; further, the particle size of the inorganic filler is preferably 1-5 μm.

[0066] The preferred heat stabilizer of the present invention is one of inorganic phosphates such as phosphate, phosphite, hypophosphite, and pyrophosphate.

[0067] Another object of the present invention is to provide a method for preparing the light-diffusing polyester reflective film as described above, comprising the following steps:

[0068] S1: The raw materials of layer B are mixed evenly according to the ratio and added into the extruder to obtain mixed masterbatch of layer B;

[0069] S2: The raw materials of layer A are mixed evenly according to the ratio and added into the extruder to obtain mixed masterbatch of layer A;

[0070] S3: The B layer mixed masterbatch and the A layer mixed masterbatch are respectively sent to the main extruder and the auxiliary extruder for melt extrusion, cast film, and then longitudinal stretching, transverse stretching, shaping, cooling, pulling, and winding to obtain a light diffusion polyester reflective film.

[0071] Specifically, the extruder granulation temperature in the above-mentioned S1 step is 200-260°C; the extruder granulation temperature in the above-mentioned S2 step is 260-280°C; in the above-mentioned S3 step, the B layer extruder temperature is 260-290°C, the A layer extruder temperature is 260-290°C, the three-layer co-extrusion die head temperature is 270-290°C, the chilled roller temperature is 10-30°C, the longitudinal stretching multiple is 2.5-4, the transverse stretching multiple is 3-4, the shaping temperature is 220-240°C, and the cooling temperature is 60-200°C; and preferably, the total thickness of the light-diffusing polyester reflective film is 188±3μm.

[0072] The preparation method of the light-diffusing polyester reflective film provided by the present invention realizes an efficient and stable production process through precisely controlled process steps. The raw materials of the B layer and the A layer are melt-extruded after being evenly mixed at a corresponding temperature, and the mechanical properties and dimensional stability of the film are improved by coordinating the steps of longitudinal stretching, transverse stretching and shaping. In addition, the temperature of the die head and the temperature of the chilled roller are precisely controlled to ensure the molding quality and stability of the film. The preparation method of the present invention simplifies the production process, improves the convenience of operation, and ensures the quality and performance of the light-diffusing polyester reflective film through precise temperature control and optimized process parameters, thereby meeting the market demand for high-performance light-diffusing polyester reflective film.

[0073] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below.

[0074] Unless otherwise specified, the compatibilizers in the embodiments of the present invention and the comparative examples are all vinyl trimethoxy silane; the inorganic fillers are barium sulfate and titanium dioxide; the toughening agents are all GMA-g-SEBS; the heat stabilizer in the A layer mixed masterbatch is a phosphate type heat stabilizer; the heat stabilizer in the B layer mixed masterbatch is a phosphite type heat stabilizer; the light stabilizers are all triazine light stabilizers; the antistatic agents are all stearyl trialkyl quaternary ammonium hydrochloride antistatic agents; the hydrolysis resistance agents are all polymeric carbodiimide hydrolysis resistance agents; the amounts of materials used in the embodiments and the comparative examples are all measured in parts by weight.

[0075] The light-diffusing polyester reflective films and the preparation methods thereof in the embodiments and comparative examples of the present invention are prepared as follows:

[0076] S1: According to the formula, polyethylene terephthalate chips, inorganic fillers, phosphate heat stabilizers, triazine light stabilizers, stearyl trialkyl quaternary ammonium hydrochloride antistatic agents, and polymeric carbodiimide hydrolysis resistance agents are mixed uniformly and added into a twin-screw extruder to obtain a layer A mixed masterbatch; various parameters in the preparation process of the layer A mixed masterbatch in each embodiment of the present invention are shown in Table 1, and various parameters in the preparation process of the layer A mixed masterbatch in each comparative example of the present invention are the same as those in Example 5.

[0077] Table 1

[0078]

[0079]

[0080] S2: According to the formula, deionized water, ethanol and vinyltrimethoxysilane were added into the container, stirred at 60°C for 15 minutes, then low-melting-point polyolefin was added and stirred for 3 hours, vacuum filtered and dried at 80°C for 4 hours to obtain pretreated low-melting-point polyolefin; then mixed evenly with silicone resin and added into a twin-screw extruder to obtain a functional foaming masterbatch; various parameters in the preparation process of the functional foaming masterbatch in the embodiments of the present invention and the comparative examples are shown in Table 2.

[0081] Table 2

[0082]

[0083] S3: According to the formula, polyethylene terephthalate chips, the above-mentioned functional foaming masterbatch, high melting point polyolefin, inorganic filler, GMA-g-SEBS, and phosphite type heat stabilizer are mixed evenly and added into a twin-screw extruder to obtain a B layer mixed masterbatch; various parameters in the preparation process of the B layer mixed masterbatch of each embodiment of the present invention and the comparative example are shown in Table 3.

[0084] Table 3

[0085]

[0086] S4: The above-mentioned B layer mixed masterbatch and A layer mixed masterbatch are respectively sent to the B layer extruder and the A layer extruder through the material conveying system for melt extrusion, and the melt is cast on the chilled roller after passing through the three-layer co-extrusion die to form a thick sheet, and then the light diffusion polyester reflective film is obtained after longitudinal stretching, transverse stretching, shaping, cooling, pulling, and winding. The various measured values ​​shown in the embodiments of the present invention and the comparative examples are measured according to the following methods.

[0087] Thickness: measured by vertical optical meter in accordance with national standard GB / T 13542.2-2021, sample size: 300mm*100mm;

[0088] Transmittance and haze: measured with a haze meter according to ASTM D1003 standard, sample size: 50mm*50mm;

[0089] Reflectivity: measured by spectrophotometer, sample size: 50mm*50mm;

[0090] TGA (Thermogravimetric Analysis): Tested using a thermogravimetric analyzer.

[0091] Table 4 shows the parameters and properties of the light-diffusing polyester reflective films in the various embodiments of the present invention and the comparative examples during the preparation process.

[0092] Table 4

[0093]

[0094]

[0095] The TGA data of the functional foaming masterbatch in Example 5 of the present invention and the conventional unmodified polypropylene resin are shown in Table 5. The unmodified polypropylene resin is Yangzi Petrochemical C4006B.

[0096] Table 5

[0097]

[0098] It can be seen from the TGA comparison data in Table 5 that, compared with the conventional unmodified polypropylene resin, the heat resistance of the functional foaming masterbatch prepared in Example 5 after being modified with the silicone resin is significantly improved.

[0099] Among them, the difference between Comparative Example 1 and Example 3 is that Comparative Example 1 does not add high melting point polyolefin, functional foaming masterbatch, GMA-g-SEBS, and phosphite type thermal stabilizer. It can be seen that the reflectivity of Example 3 is significantly improved due to the foaming effect of the incompatible resin, and the introduction of the silicone resin also increases its haze.

[0100] The difference between Comparative Example 2 and Example 5 is that no functional foaming masterbatch and high melting point polyolefin are added to Comparative Example 2. It can be seen that in Example 5, due to the addition of incompatible resin, the foaming effect significantly improves the reflectivity, and the introduction of silicone resin also increases its haze. The compatibilizer and thermal stabilizer make the incompatible resin have a better interface effect with PET.

[0101] The difference between Comparative Example 3 and Example 4 is that high melting point polyolefin is not added in Comparative Example 3, the haze of Comparative Example 3 is similar to that of Example 4, and the reflectivity is slightly lower, indicating that the foaming effect is better when high melting point polyolefin is added.

[0102] The difference between Comparative Example 4 and Example 5 is that no functional foaming masterbatch is added to Comparative Example 4, and the haze of Example 5 is significantly improved, and the reflectivity is slightly higher, indicating that the low-melting-point polyolefin modified by the silicone resin can effectively improve the light diffusion of the polyester film; in addition, it can be seen from the data of Examples 5-9 that, under the same incompatible resin content, the higher the content of the functional foaming masterbatch, the more obvious the increase in haze and the better the light diffusion performance, indicating that the silicone resin has good dispersion within the group; and, the difference between Comparative Example 4 and Comparative Example 2 is that a high-melting-point polyolefin is added, and its reflectivity is significantly improved, while the haze is not significantly improved, indicating that the light diffusion performance is poor.

[0103] The difference between Comparative Example 5 and Example 4 is that no functional foaming masterbatch is added to Comparative Example 5, and the reflectivity and haze of Example 4 are significantly improved. At the same time, by comparing with Example 4, it is shown that the low-melting-point polyolefin modified by silicone resin can effectively improve the light diffusion of the polyester film.

[0104] The difference between Comparative Example 6 and Example 5 is that the functional foaming masterbatch of Comparative Example 6 is prepared according to the following method: 10 parts of deionized water, 70 parts of ethanol, 20 parts of vinyltrimethoxysilane, 80 parts of polypropylene powder and 20 parts of vinyl silicone resin powder are added into a container, mixed, stirred evenly and then added into a twin-screw extruder to obtain a functional foaming masterbatch; the reflectivity of Comparative Example 6 is lower than that of Example 5, indicating that the functional foaming masterbatch of Comparative Example 6 has not achieved sufficient modification effect, and it has few pores and low foaming efficiency, resulting in reduced reflectivity.

[0105] The difference between Comparative Example 7 and Example 5 is that the functional foaming masterbatch of Comparative Example 7 is prepared by modification with other types of silicone resins, namely polydimethylsiloxane. The reflectivity and haze of Comparative Example 7 are slightly lower than those of Example 5, indicating that vinyltrimethoxysilane has a better modification effect on low-melting-point polyolefins, which may be due to the similar compatibility effect of terminal vinyl groups; and, compared with Comparative Example 7, at the same amount of incompatible resins, Example 5 has a significantly improved haze and a relatively consistent reflectivity after adding low-melting-point polyolefin modified with silicone resin, indicating that the low-melting-point polyolefin modified with silicone resin has a synergistic effect with the high-melting-point polyolefin, and can replace part of the high-melting-point polyolefin to reduce costs.

[0106] The difference between Comparative Example 8 and Example 5 is that the functional foaming masterbatch in Example 5 is replaced by conventional low-melting polyolefin polypropylene in equal parts by weight, and the reflectivity is significantly reduced, indicating that the heat resistance of the low-melting polyolefin modified with the silicone resin is improved, and the collapse rate of the bubbles formed at high temperature is reduced, so that the film maintains a good reflectivity; and it can be seen from the data of Comparative Examples 8-11 that, under the same incompatible resin content, the reflectivity decreases with the increase of the polypropylene content.

[0107] The difference between Comparative Example 12 and Example 5 is that the weight proportion of the high melting point polyolefin in Comparative Example 12 is 40 parts. Since the polyolefin content is too high, the B layer has more pores and poor film-forming properties, and no effective data can be obtained.

[0108] It can be seen from the above data that the present invention reduces the production cost by introducing a low-melting-point polyolefin modified with a silicone resin into the PET polyester core layer, compounding it with a high-melting-point polyolefin and utilizing the synergistic effect between the components, while making the prepared light-diffusing polyester reflective film have good reflectivity and light-diffusing performance.

[0109] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A light-diffusing polyester reflective film, characterized in that: The light-diffusing polyester reflective film is an ABA three-layer co-extruded structure; The materials of the A layer include the following components in parts by weight: 40-80 pieces of polyethylene terephthalate slices; 5-30 parts of inorganic filler; Heat stabilizer 0.1-1 part; Light stabilizer 1-5 parts; Antistatic agent 1-10 parts; 1-10 parts of hydrolysis resistance agent; The materials of the B layer include the following components in parts by weight: 40-80 pieces of polyethylene terephthalate slices; Functional foaming masterbatch 1-30 parts; 5-35 parts of high melting point polyolefin; 10-30 parts of inorganic filler; Toughener 0.1-2 parts; Heat stabilizer 0.1-2 parts; The functional foaming masterbatch is obtained by modifying low melting point polyolefin with silicone resin; The functional foaming masterbatch in layer B is prepared as follows: Add deionized water, ethanol and a compatibilizer into a container and stir evenly, then add a low-melting-point polyolefin and continue stirring, and obtain a pretreated low-melting-point polyolefin after drying; then mix the low-melting-point polyolefin and the silicone resin evenly and add them into an extruder to obtain a functional foaming masterbatch; The mass ratio of the deionized water, ethanol, compatibilizer, low melting point polyolefin and silicone resin is (1-10): (40-70): (10-30): (50-80): (10-20); The low melting point polyolefin is at least one of polyethylene, polypropylene and polybutylene.

2. The light-diffusing polyester reflective film according to claim 1, wherein: The organic silicone resin is at least one of polymethyl silicone resin, polyethyl silicone resin, polyphenyl silicone resin, polymethylphenyl silicone resin and vinyl organic silicone resin.

3. The light-diffusing polyester reflective film according to claim 1, wherein: The compatibilizer is at least one of vinyl trichlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, phenylaminopropyl trimethoxysiloxane, γ-aminopropyl triethoxysiloxane, acrylate propyl trimethoxysiloxane, and γ-methacryloxypropyl trimethoxysiloxane.

4. The light-diffusing polyester reflective film according to claim 1, wherein: The polyethylene is at least one of high-density polyethylene HDPE, linear low-density polyethylene LLDPE, and low-density polyethylene LDPE.

5. The light-diffusing polyester reflective film according to any one of claims 1 to 4, characterized in that: The high melting point polyolefin in layer B is at least one of poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, polystyrene, polymethylstyrene, polydimethylstyrene, polyvinyl fluoride and cycloolefin copolymer.

6. The light-diffusing polyester reflective film according to any one of claims 1 to 4, characterized in that: The anti-hydrolysis agent in layer A is at least one of monomeric carbodiimide, polymeric carbodiimide, bisphenol A diglycidyl ether, tetrakis(phenylglycidyl ether)ethane, and trimethoxy[3-(glycidyl ether)propyl]silane.

7. A method for preparing a light-diffusing polyester reflective film according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: The raw materials of layer B are mixed evenly according to the ratio and added into the extruder to obtain mixed masterbatch of layer B; S2: The raw materials of layer A are mixed evenly according to the ratio and added into the extruder to obtain mixed masterbatch of layer A; S3: The B layer mixed masterbatch and the A layer mixed masterbatch are respectively sent to the main extruder and the auxiliary extruder for melt extrusion, cast film, and then longitudinal stretching, transverse stretching, shaping, cooling, pulling, and winding to obtain a light diffusion polyester reflective film.

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