Blended resin particle and application of blended resin particle as light diffusion agent

Abstract

The invention provides blended resin particles. The blended resin particles are prepared from PET (Polyethylene Terephthalate) resin and cycloolefin polymer resin through at least one-time melt extrusion granulation. The invention also provides application of the blended resin particles as a light diffusion agent. The invention further provides a PET light diffusion base film and a preparation method thereof. When the blended resin particle provided by the invention is used for preparing the light diffusion film, the optical performance and the mechanical performance of the film can be remarkably improved, and the blended resin particle is wide in raw material source, simple and convenient in preparation process, easy to operate and control, free of complex manufacturing equipment and good in industrial practicability. The PET light diffusion base film provided by the invention has high light transmittance and high haze, and also has good heat resistance, so that the PET light diffusion base film is suitable for being used as a light diffusion film to be widely applied to multiple fields such as liquid crystal display panels, control panels and flexible displays, and has important economic and social values.

Description

Technical Field

[0001] The invention relates to the field of optical film processing, in particular to a blended resin particle and use of the blended resin particle as a light diffuser, and also to a PET light diffusion base film and a preparation method thereof. Background Art

[0002] Liquid crystal displays (LCDs) require a diffusion film to atomize the light emitted from a point light source into a uniform surface light source, thereby obtaining a light output suitable for the application. Therefore, a light diffusion film usually needs to have high transmittance and high haze. Currently, there are two ways to prepare light diffusion films. One is to treat a highly transparent film by coating, polishing, etc., and use the roughness of the optical film surface to produce light diffusion. However, the surface of this optical film is prone to damage, and it is easy to curl after being heated, thereby reducing the light diffusion effect.

[0003] For example, Chinese patent CN 114578465A discloses a PET-based diffusion film and a preparation method thereof. The PET-based diffusion film has an A / B / C three-layer structure, wherein layer A is a molded layer, layer B is a core layer, and layer C is an anti-sticking layer. Layer A includes a modified polyester resin, layer B includes a crystalline polyester resin, and layer C includes a crystalline polyester resin and an anti-sticking masterbatch. The surface of layer A has a semi-concave spherical pattern made by molding.

[0004] Another method for preparing a light diffusion film is to add a light diffusion agent internally, using the difference in refractive index of different materials to form light diffusion. The optical film prepared by this method can avoid the phenomenon of curling of the light diffusion film after being heated. The PET (polyethylene terephthalate) base film prepared by adding a light diffusion agent has good light transmittance, and also has the advantages of good flatness, easy processing, and resistance to ultraviolet radiation.

[0005] For example, Chinese patent CN 112433279A discloses a method for preparing a light diffusion film, comprising the following steps: A. hydroxylating PET; B. preparing a diffusion layer coating: (1) preparing hollow silica nanoparticles; (2) preparing a diffusion layer coating: diluting UV-curing acrylate with methyl isobutyl ketone to obtain a UV-curing acrylate solution, then mixing the hollow silica nanoparticles with the UV-curing acrylate solution to obtain a suspension, then using a coating machine to coat the suspension on the hydroxylated PET, keeping it in the dark, and then curing it by ultraviolet irradiation to obtain a light diffusion film. The hollow silica nanoparticles in the light diffusion film have good dispersibility in the diffusion layer, can undergo multiple scattering, can improve the light diffusion effect and transmittance, and thus can achieve a higher transmittance, so that the haze and transmittance of the light diffusion film are balanced. Although this preparation method can achieve high transmittance and high haze, it has the disadvantages of complex preparation process and low industrial applicability.

[0006] Therefore, there is an urgent need to develop a light diffusion film that has both high light transmittance and high haze, good heat resistance, and is easy to prepare. Summary of the invention

[0007] In order to make up for the deficiencies in the prior art, one object of the present invention is to provide a blended resin particle, which can be used as a light diffuser to improve the optical properties and mechanical properties of a light diffusion film.

[0008] Another object of the present invention is to provide uses of the blended resin particles.

[0009] Another object of the present invention is to provide a PET light diffusion base film and a preparation method thereof.

[0010] The first aspect of the present invention provides a blended resin particle, which is obtained by melt extrusion granulation of PET resin and cycloolefin polymer (COC / COP) resin at least once, wherein the mass ratio of the PET resin to the cycloolefin polymer resin is 10:1-10.

[0011] Usually PET resin and COP resin are incompatible, and COP resin cannot be directly added to PET substrate to modify it. However, the inventors have found that after PET resin and COP resin are subjected to one or more "melt extrusion granulation", the compatibility of the two can be improved, and when the obtained blended resin particles are added to the PET substrate to prepare PET film, COP resin has good and uniform distribution in the film, thus significantly improving the optical properties (such as haze) of the PET film, plus the high light transmittance of the PET film itself, the modified PET film can simultaneously have high light transmittance and high haze, and is therefore very suitable for preparing light diffusion film. Moreover, the PET film after COP resin modification also has improved mechanical properties and heat resistance, and after being placed at high temperature, light transmittance and haze are also substantially unchanged. In addition, the blended resin particles of the present invention also have the advantages of wide sources of raw materials, low cost, simple preparation process, and being suitable for industrial production.

[0012] In the blended resin particles provided by the present invention, the cycloolefin polymer resin may be any type commonly found in the resin field, for example, may be a polymer having the structure shown below:

[0013]

[0014] Among them, R 1 , R 2 Each of them can be independently H, benzene, toluene, ethylbenzene, xylene or a C1-C8 alkyl group; x and y can be independently 10-1000, preferably 50-200; m can be 0-10, preferably 1-3.

[0015] In some preferred embodiments, in the structure of the cycloolefin polymer, R 1 and R 2 are both H.

[0016] In the blend resin particles provided by the present invention, the mass ratio of the PET resin to the COP resin can be about 10:1, about 10:2, about 10:3, about 10:4, about 10:5, about 10:6, about 10:7, about 10:8, about 10:9, about 10:10 or can be any mass ratio range. In some preferred embodiments, the mass ratio of the PET resin to the COP resin can be 10:5 to 10.

[0017] In the blend resin particles provided by the present invention, the PET resin and the cycloolefin polymer resin can be first pulverized to a particle size of less than 100 μm before melt extrusion granulation, for example, using a crusher for pulverization. Pulverizing the resin material to a small particle size can make the mixing of the two materials more sufficient and uniform, so as to further enhance the compatibility between the two.

[0018] In the blend resin particles provided by the present invention, the particle size of the blend resin particles can be the particle size of common resin masterbatch particles in the art. In some preferred embodiments, the particle size of the blend resin particles can be 1 to 10 mm, for example, it can be about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm or can be any particle size range. In some more preferred embodiments, the particle size of the blend resin particles can be 1 to 5 mm.

[0019] In the blend resin particles provided by the present invention, the more times the melt extrusion granulation process is carried out, the better the compatibility of the two resins in the obtained blend resin particles, but the manufacturing cost will relatively increase. Based on the balance between the two, the melt extrusion granulation process is usually one or two times, and the obtained blend resin particles can meet the requirements as a light diffusing agent.

[0020] In the blend resin particles provided by the present invention, the melt extrusion granulation can be carried out in a common twin-screw extruder in the art. Among them, the screw speed can be 50 to 200 r / min, for example, it can be 60 to 100 r / min, the temperature of the first zone of the screw can be 180 to 220 °C, and the temperatures of the second, third, fourth, fifth, sixth, seventh, and eighth zones of the screw can be independently 200 to 280 °C, and the die head temperature can be 160 to 220 °C.

[0021] In some preferred embodiments, the temperature of the first zone of the screw can be 180 - 190 °C, the temperature of the second zone of the screw can be 210 - 230 °C, the temperature of the third zone of the screw can be 230 - 250 °C, the temperature of the fourth zone of the screw can be 230 - 250 °C, the temperature of the fifth zone of the screw can be 230 - 250 °C, the temperature of the sixth zone of the screw can be 210 - 230 °C, the temperature of the seventh zone of the screw can be 200 - 210 °C, and the temperature of the eighth zone of the screw can be 200 - 210 °C.

[0022] In some preferred embodiments, the die temperature can be 180 - 200 °C.

[0023] In some preferred embodiments, PET resin and COP resin (such as the mixture after being crushed into powder) can be added to the twin-screw extruder through a feeder. The rotational speed of the feeder can be 1 - 50 r / min, for example, it can be 5 - 30 r / min.

[0024] The second aspect of the present invention provides the use of the blend resin particles according to any one of the above technical solutions as a light diffusing agent.

[0025] In some preferred embodiments, the light diffusing agent is used for preparing a light diffusing film, such as preparing a PET light diffusing base film.

[0026] The third aspect of the present invention provides a method for preparing a PET light diffusing base film. The preparation method is as follows: adding the blend resin particles according to any one of the above technical solutions as a light diffusing agent to a PET substrate for melt extrusion, and then successively passing through film forming and stretching to obtain the PET light diffusing base film.

[0027] In the method for preparing the PET light diffusing base film provided by the present invention, an appropriate amount of blend resin particles can be added according to the performance requirements of the PET base film. In some preferred embodiments, the mass ratio of the light diffusing agent to the PET substrate can be 1:0.5 - 5, for example, it can be about 1:0.5, about 1:0.8, about 1:1, about 1:1.2, about 1:1.5, about 1:2, about 1:2.5, about 1:3, about 1:3.5, about 1:4, about 1:4.5, about 1:5 or can be any mass ratio range. In some more preferred embodiments, the mass ratio of the light diffusing agent to the PET substrate can be 1:0.5 - 1.5.

[0028] In the method for preparing the PET light-diffusing base film provided by the present invention, the melt extrusion can be carried out in a common twin-screw extruder in the art. Among them, the screw speed can be 50 to 200 r / min, for example, it can be 60 to 100 r / min. The temperature of the first zone of the screw can be 180 to 220 °C, and the temperatures of the second, third, fourth, fifth, sixth, seventh, and eighth zones of the screw can be independently 200 to 280 °C. The die head temperature can be 160 to 220 °C.

[0029] In some preferred embodiments, the temperature of the first zone of the screw can be 180 to 190 °C, the temperature of the second zone of the screw can be 210 to 230 °C, the temperature of the third zone of the screw can be 230 to 250 °C, the temperature of the fourth zone of the screw can be 230 to 250 °C, the temperature of the fifth zone of the screw can be 230 to 250 °C, the temperature of the sixth zone of the screw can be 210 to 230 °C, the temperature of the seventh zone of the screw can be 200 to 210 °C, and the temperature of the eighth zone of the screw can be 200 to 210 °C.

[0030] In some preferred embodiments, the die head temperature can be 180 to 200 °C.

[0031] In some preferred embodiments, the PET base material and the light diffusing agent can be added to the twin-screw extruder through a feeder. The feeder speed can be 1 to 50 r / min, for example, it can be 5 to 30 r / min.

[0032] In some preferred embodiments, the film-forming method can be the common casting forming in the art, or a common casting forming device or apparatus in the art can be used.

[0033] In some preferred embodiments, the stretching method can be the common static biaxial stretching in the art, or a common static biaxial stretching device or apparatus in the art can be used. In some more preferred embodiments, the longitudinal stretching temperature can be 110 to 140 °C, the longitudinal stretching ratio can be 2 to 3.5, the transverse stretching temperature can be 120 to 150 °C, the transverse stretching ratio can be 2 to 3, and the heat setting temperature can be 230 to 250 °C.

[0034] The fourth aspect of the present invention provides a PET light-diffusing base film, which is obtained by the method for preparing the PET light-diffusing base film according to any one of the above technical solutions.

[0035] In some preferred embodiments, the thickness of the PET light-diffusing base film can be less than 0.535 mm (for example, it can be less than 0.53 mm, 0.525 mm, 0.52 mm, or even less than 0.515 mm). In some more preferred embodiments, the thickness of the PET light-diffusing base film can be 0.50 to 0.53 mm.

[0036] In some preferred embodiments, as measured by ASTM D1003, the light transmittance of the PET light-diffusing base film is greater than or equal to 90% and the haze is greater than or equal to 85% (for example, it can be greater than or equal to 86%, 87%, 88%, or even greater than or equal to 89%).

[0037] In some preferred embodiments, after heating at 80 - 90 °C for 20 - 30 hours (for example, heating for 20 - 24 hours), as measured by ASTM D1003, the light transmittance of the PET light-diffusing base film is still greater than or equal to 90% and the haze is still greater than or equal to 85% (for example, it can be greater than or equal to 86%, 87%, 88%, or even greater than or equal to 89%).

[0038] The technical solutions provided by the present invention have the following advantages:

[0039] 1) The blend resin particles provided by the present invention can be used as a new type of light diffusing agent. When used to prepare a light diffusing film, they can significantly improve the optical and mechanical properties of the film.

[0040] 2) The blend resin particles provided by the present invention are formed from common PET resin and COP resin. The raw materials are widely sourced, the preparation process is simple, easy to operate and control, and no complex manufacturing equipment is required. Therefore, it has good industrial practicability and broad industrialization prospects.

[0041] 3) The PET light-diffusing base film provided by the present invention is a blend type film, modified by the blend resin particles described in the present invention. Compared with traditional PET films, it can have both high light transmittance and high haze, and also has good heat resistance. Therefore, it is suitable as a light diffusing film and is widely used in many fields such as liquid crystal display panels, control panels, and flexible displays, and has great economic and social value. Detailed Embodiments

[0042] The technical solutions of the present invention will be further described in detail below with specific examples.

[0043] The sources of raw materials and testing equipment used in the examples and comparative examples of the present invention are as follows:

[0044] PET: Commercially available, Sinopec FG720;

[0045] COP: Commercially available, Zeon K26R from Japan;

[0046] Twin-screw extruder: Guangdong Ha'er Machinery Equipment Company;

[0047] Cast film machine: Labtech Engineering Co., LTD;

[0048] Transmittance / Haze Meter: Shanghai Shenguang Company (WGT-S), the measurement of transmittance / haze refers to ASTM D1003 standard.

[0049] Other raw materials or reagents used in the examples and comparative examples of the present invention are all commercially available products without special instructions.

[0050] The percentages used in the examples and comparative examples of the present invention are all mass percentages without special instructions.

[0051] Preparation of PET base film in Example 1

[0052] Add 10 kg of PET particles and 10 kg of COP particles into a crusher and mix them evenly, then crush them into powders with a particle size below 100 μm. Add the evenly mixed powders into a twin-screw extruder through a feeder for melt extrusion, and then cool to room temperature and pelletize to obtain diffusing agent particles-1 with a particle size of 3-5 mm. Among them, the feeder rotation speed is 30 r / min, the screw rotation speed is 100 r / min, the temperature of zone 1 of the screw is 180 °C, the temperature of zone 2 is 220 °C, the temperature of zone 3 is 240 °C, the temperature of zone 4 is 240 °C, the temperature of zone 5 is 240 °C, the temperature of zone 6 is 220 °C, the temperature of zone 7 is 200 °C, the temperature of zone 8 is 200 °C, and the die head temperature is 180 °C.

[0053] Mix 10 kg of diffusing particles-1 and 10 kg of PET particles evenly and then add them into a feeder. Add the materials into a twin-screw extruder through the feeder for melt extrusion. After the materials are extruded from the extruder, they are cast into a film and then stretched and shaped by a static biaxial stretcher. Among them, the feeder rotation speed is 30 r / min, the screw rotation speed is 80 r / min, the temperature of zone 1 of the screw is 180 °C, the temperature of zone 2 is 220 °C, the temperature of zone 3 is 240 °C, the temperature of zone 4 is 240 °C, the temperature of zone 5 is 240 °C, the temperature of zone 6 is 220 °C, the temperature of zone 7 is 200 °C, the temperature of zone 8 is 200 °C, and the die head temperature is 180 °C. The longitudinal stretching temperature of the film is 130 °C, the stretching ratio is 3, the transverse stretching temperature is 130 °C, the stretching ratio is 3, and the heat setting temperature is 240 °C.

[0054] The thickness and performance test results of the obtained PET base film are shown in Table 1.

[0055] Preparation of PET base film in Example 2

[0056] Add 10 kg of PET particles and 5 kg of COP particles to a crusher, mix them evenly, and grind them into a powder with a particle size below 100 μm. Add the evenly mixed powder to a twin-screw extruder through a feeder for melt extrusion, then cool it to room temperature and pelletize to obtain diffusing agent particles-2 with a particle size of 3-5 mm. Among them, the feeder rotation speed is 30 r / min, the screw rotation speed is 100 r / min, the temperature of the first zone of the screw is 180 °C, the second zone is 220 °C, the third zone is 240 °C, the fourth zone is 240 °C, the fifth zone is 240 °C, the sixth zone is 220 °C, the seventh zone is 200 °C, the eighth zone is 200 °C, and the die head temperature is 180 °C.

[0057] Mix 10 kg of diffusing particles-2 and 10 kg of PET particles evenly, then add them to a feeder. Feed the material into a twin-screw extruder through the feeder for melt extrusion. After the material is extruded from the extruder, it is cast into a film and then stretched and shaped by a static biaxial stretcher. Among them, the feeder rotation speed is 30 r / min, the screw rotation speed is 80 r / min, the temperature of the first zone of the screw is 180 °C, the second zone is 220 °C, the third zone is 240 °C, the fourth zone is 240 °C, the fifth zone is 240 °C, the sixth zone is 220 °C, the seventh zone is 200 °C, the eighth zone is 200 °C, and the die head temperature is 180 °C. The longitudinal stretching temperature of the film is 130 °C, the stretching ratio is 3, the transverse stretching temperature is 130, the stretching ratio is 3, and the heat setting temperature is 240 °C.

[0058] The thickness and performance test results of the prepared PET base film are shown in Table 1.

[0059] Preparation of PET Base Film in Example 3

[0060] Add 10 kg of PET particles and 2 kg of COP particles to a crusher, mix them evenly, and grind them into a powder with a particle size below 100 μm. Add the evenly mixed powder to a twin-screw extruder through a feeder for melt extrusion, then cool it to room temperature and pelletize to obtain diffusing agent particles-3 with a particle size of 3-5 mm. Among them, the feeder rotation speed is 30 r / min, the screw rotation speed is 100 r / min, the temperature of the first zone of the screw is 180 °C, the second zone is 220 °C, the third zone is 240 °C, the fourth zone is 240 °C, the fifth zone is 240 °C, the sixth zone is 220 °C, the seventh zone is 200 °C, the eighth zone is 200 °C, and the die head temperature is 180 °C.

[0061] Mix 10 kg of diffusion particles - 3 and 10 kg of PET particles evenly, then add them to the feeder. Feed the material into the twin - screw extruder through the feeder for melting and extrusion. After the material is extruded from the extruder, it is cast into a film, and then stretched and shaped by a static biaxial stretcher. Among them, the rotational speed of the feeder is 30 r / min, the rotational speed of the screw is 80 r / min, the temperature of the 1st zone of the screw is 180 °C, the temperature of the 2nd zone is 220 °C, the temperature of the 3rd zone is 240 °C, the temperature of the 4th zone is 240 °C, the temperature of the 5th zone is 240 °C, the temperature of the 6th zone is 220 °C, the temperature of the 7th zone is 200 °C, the temperature of the 8th zone is 200 °C, and the temperature of the die head is 180 °C. The longitudinal stretching temperature of the film is 130 °C, the stretching ratio is 3, the transverse stretching temperature is 130 °C, the stretching ratio is 3, and the heat - setting temperature is 240 °C.

[0062] The thickness and performance test results of the prepared PET base film are shown in Table 1.

[0063] Preparation of PET base film in Comparative Example 1

[0064] Add 20 kg of PET particles to the feeder. Feed the material into the twin - screw extruder through the feeder for melting and extrusion. After the material is extruded from the screw, it is cast into a film, and then stretched and shaped by a static biaxial stretcher. Among them, the rotational speed of the feeder is 30 r / min, the rotational speed of the screw is 80 r / min, the temperature of the 1st zone of the screw is 180 °C, the temperature of the 2nd zone is 220 °C, the temperature of the 3rd zone is 240 °C, the temperature of the 4th zone is 240 °C, the temperature of the 5th zone is 240 °C, the temperature of the 6th zone is 220 °C, the temperature of the 7th zone is 200 °C, the temperature of the 8th zone is 200 °C, and the temperature of the die head is 180 °C. The longitudinal stretching temperature of the film is 130 °C, the stretching ratio is 3, the transverse stretching temperature is 130 °C, the stretching ratio is 3, and the heat - setting temperature is 240 °C.

[0065] The thickness and performance test results of the prepared PET base film are shown in Table 1.

[0066] Preparation of PET base film in Comparative Example 2

[0067] Mix 5 kg of COP particles and 20 kg of PET particles evenly, then add them to the feeder. Feed the material into the twin - screw extruder through the feeder for melting and extrusion. After the material is extruded from the extruder, it is cast into a film, and then stretched and shaped by a static biaxial stretcher. Among them, the rotational speed of the feeder is 30 r / min, the rotational speed of the screw is 80 r / min, the temperature of the 1st zone of the screw is 180 °C, the temperature of the 2nd zone is 220 °C, the temperature of the 3rd zone is 240 °C, the temperature of the 4th zone is 240 °C, the temperature of the 5th zone is 240 °C, the temperature of the 6th zone is 220 °C, the temperature of the 7th zone is 200 °C, the temperature of the 8th zone is 200 °C, and the temperature of the die head is 180 °C. The longitudinal stretching temperature of the film is 130 °C, the stretching ratio is 3, the transverse stretching temperature is 130 °C, the stretching ratio is 3, and the heat - setting temperature is 240 °C.

[0068] The thickness and performance test results of the prepared PET base film are shown in Table 1.

[0069] Preparation of the PET base film of Comparative Example 3

[0070] Mix 5 kg of COP particles and 20 kg of PET particles evenly and add them to the feeder. Then add the materials to the twin-screw extruder through the feeder for melting and extrusion. Cool to room temperature and pelletize to obtain PET and COP mixed particles with a particle size of 3 - 5 mm. Then re-add the mixed particles to the twin-screw extruder through the feeder for secondary melting and extrusion. After extruding from the extruder, cast into a film, and then stretch and shape it through a static biaxial stretcher. During the two melting and extrusion processes, the rotational speed of the feeder is 30 r / min, the rotational speed of the screw is 80 r / min, the temperature of zone 1 of the screw is 180 °C, the temperature of zone 2 is 220 °C, the temperature of zone 3 is 240 °C, the temperature of zone 4 is 240 °C, the temperature of zone 5 is 240 °C, the temperature of zone 6 is 220 °C, the temperature of zone 7 is 200 °C, the temperature of zone 8 is 200 °C, and the temperature of the die head is 180 °C. The longitudinal stretching temperature of the film is 130 °C, the stretching ratio is 3, the transverse stretching temperature is 130 °C, the stretching ratio is 3, and the heat setting temperature is 240 °C.

[0071] The thickness and performance test results of the prepared PET base film are shown in Table 1.

[0072] Table 1 Film performance test results

[0073]

[0074] From the test results of Examples 1 - 3 and Comparative Example 1, it can be seen that the PET film without adding a diffusing agent in Comparative Example 1 has high light transmittance, but the haze is only 2.4%. The light transmittance of the PET films prepared in Examples 1 - 3 is higher than 90%, and the haze is higher than 86%. This shows that the resin particles after mixing PET and COP play the role of a diffusing agent in the film. Moreover, with the increase of the COP content, the haze of the product is also significantly improved, and the modified PET film can be used as a diffusing film.

[0075] On the other hand, the minimum thickness of the PET film without adding a diffusing agent is 0.596 mm (the film will break if the film thickness is further reduced). The film thickness of Examples 1 - 3 after adding diffusing agent particles can be lower than 0.528 mm, indicating that the diffusing agent particles of the present invention can also improve the strength of the PET film, which is beneficial to reducing the film thickness. At the same time, after heating the PET films of Examples 1 - 3 at 85 °C for 24 hours, their light transmittance and haze do not decrease significantly, indicating that the diffusing agent particles are also beneficial to improving the heat resistance of the PET film.

[0076] From the test results of Examples 1-3 and Comparative Examples 2 and 3, it can be seen that if COP is directly added to the PET film as a diffusing agent (as shown in Comparative Example 2), due to the very poor compatibility between the two, although the haze and film thickness are improved to some extent, the improvement effect is very limited, and the obtained PET film even shows visible non-uniformity to the naked eye. Even if two melt extrusions are carried out (as shown in Comparative Example 3), the improvement in the compatibility between the two is not obvious.

[0077] Unless otherwise specified, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0078] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments and is only defined by the claims.

Claims

1. A blend resin particle, characterized in that it is obtained by melt extrusion granulation of PET resin and cycloolefin polymer resin at least once, wherein the mass ratio of the PET resin to the cycloolefin polymer resin is 10:1 to 10.

2. The blend resin particle according to claim 1, characterized in that the mass ratio of the PET resin to the cycloolefin polymer resin is 10:5 to 10; and / or the PET resin and the cycloolefin polymer resin are pulverized to a particle size of less than 100 μm before melt extrusion granulation.

3. The blend resin particle according to claim 1 or 2, characterized in that the particle size of the blend resin particle is 1 to 10 mm, preferably 1 to 5 mm; and / or the melt extrusion granulation is carried out once or twice.

4. The blend resin particle according to any one of claims 1-3, characterized in that the melt extrusion granulation is carried out in a twin-screw extruder, wherein the screw speed is 50 to 200 r / min, preferably 60 to 100 r / min, the temperature of the first screw zone is 180 to 220 °C, and the temperatures of the second, third, fourth, fifth, sixth, seventh, and eighth screw zones are each independently 200 to 280 °C, and the die head temperature is 160 to 220 °C.

5. Use of the blend resin particle according to any one of claims 1-4 as a light diffusing agent; Preferably, the light diffusing agent is used for preparing a light diffusing film.

6. A method for preparing a PET light diffusing base film, characterized in that the blend resin particle according to any one of claims 1-4 is added as a light diffusing agent to a PET substrate for melt extrusion, and then successively subjected to film forming and stretching to obtain the PET light diffusing base film.

7. The preparation method according to claim 6, characterized in that the mass ratio of the light diffusing agent to the PET substrate is 1:0.5 to 5, preferably 1:0.5 to 1.

5.

8. The preparation method according to claim 6 or 7, characterized in that the melt extrusion is carried out in a twin-screw extruder, wherein the screw speed is 50 to 200 r / min, preferably 60 to 100 r / min, the temperature of the first screw zone is 180 to 220 °C, and the temperatures of the second, third, fourth, fifth, sixth, seventh, and eighth screw zones are each independently 200 to 280 °C, and the die head temperature is 160 to 220 °C.

9. The preparation method according to any one of claims 6-8, characterized in that the film forming method is casting forming; and / or the stretching method is static biaxial stretching, the longitudinal stretching temperature is 110 to 140 °C, the longitudinal stretching ratio is 2 to 3.5, the transverse stretching temperature is 120 to 150 °C, the transverse stretching ratio is 2 to 3, and the heat setting temperature is 230 to 250 °C.

10. A PET light diffusing base film, characterized in that the PET light diffusing base film is obtained by the preparation method according to any one of claims 6-9; Preferably, the thickness of the PET light diffusing base film is less than 0.535 mm, more preferably 0.50 to 0.53 mm; and / or As measured according to ASTM D1003, the light transmittance of the PET light diffusing base film is greater than or equal to 90% and the haze is greater than or equal to 85%.

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