Modified polyester film as well as preparation method and application thereof
By nitrogen-doping modification of silicon dioxide and compounding with barium sulfate, the shortcomings of the polyester film in terms of opening performance and light transmittance are solved, the dispersion and optical properties of the film are improved, and high light transmittance and good opening performance are achieved.
Patent Information
- Application Number
- CN202510556028.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2025-07-11
AI Technical Summary
The existing polyester films have shortcomings in opening performance, light transmittance and haze control, especially inorganic particles have poor dispersion in the matrix, resulting in poor adhesion, film breakage and optical properties.
The silicon dioxide is nitrogen-doped and modified by low-temperature plasma discharge treatment and is compounded with barium sulfate to improve the dispersion and light transmittance of silicon dioxide in the film, and to utilize the refractive index matching between barium sulfate and polyester to jointly improve the light transmittance and opening performance.
The high light transmittance and good opening of polyester film are achieved, the haze is reduced, and the production efficiency and user experience are improved.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of polyester film materials, and particularly relates to a modified polyester film, a preparation method thereof, and an application thereof. Background Art
[0002] In the field of polyester film materials, the anti-blocking property is one of the key indicators for measuring its processing applicability and end-use effect. The anti-blocking property of a film refers to the property that the film can be easily separated between layers without external force during winding, slitting, or subsequent processing. Good anti-blocking performance can not only significantly improve production efficiency, avoid problems such as film adhesion and film breakage on high-speed automated production lines, but also ensure a smooth operation experience for end-users when peeling the film. Especially in precision manufacturing fields such as packaging, electronics, and optics, this property is directly related to product yield and user experience.
[0003] Although existing preparation technologies have made certain progress, there are still many technical bottlenecks in practical applications, especially in terms of anti-blocking performance and optical properties. In the existing technology, a single inorganic particle is often added as an anti-blocking agent to improve the interlayer separation of the film. However, unmodified inorganic particles have a high surface energy and are prone to agglomeration in the polyester matrix, resulting in poor dispersibility. This not only weakens the regulation effect of the particles on the surface roughness of the film, making it impossible to effectively improve the dynamic friction coefficient, but also causes local stress concentration due to agglomerates, which is prone to film adhesion or film breakage during high-speed winding or slitting, seriously affecting production efficiency, and it is difficult to balance the requirements of high light transmittance and easy peeling. In summary, the polyester films prepared by the existing technology have significant shortcomings in terms of anti-blocking property, light transmittance, haze control, and process stability, and an innovative solution is urgently needed to prepare high-performance polyester films. Summary of the Invention
[0004] To solve the deficiencies of the existing technology, the purpose of the present invention is to provide a modified polyester film, a preparation method thereof, and an application thereof. By subjecting silica to nitrogen doping through low-temperature plasma discharge treatment, the modified silica can not only improve the anti-blocking performance of the film, but also improve the dispersibility of silica in the film, reduce the haze of the film, and increase the light transmittance. By utilizing the refractive index matching of barium sulfate and polyester, the light transmittance is further improved.
[0005] To achieve the above objectives, the present invention adopts the following technical solutions: A preparation method of a modified polyester film, comprising the following specific steps: S1. Prepare a barium sulfate composite material: Blend a high molecular polymer resin, barium sulfate, and a dispersant, and perform melt co-extrusion to prepare a barium sulfate composite material; S2. Preparation of silica composite material: Nitrogen-doped modification treatment is carried out on silica, and the modified silica, polymer resin and coupling agent are blended and melt co-extruded to prepare a silica composite material; S3. Preparation of modified polyester film: The barium sulfate composite material and the silica composite material are mixed, extruded and stretched to obtain a modified polyester film.
[0006] Preferably, the specific method for the nitrogen-doped modification treatment of silica is: The silica is subjected to low-temperature plasma discharge treatment in an inert gas atmosphere to obtain nitrogen-doped silica.
[0007] Preferably, the temperature of the low-temperature plasma discharge treatment is 40~50 °C, the working voltage is -40~-60 kV, and the nitrogen injection dose is 6×10 15 N·cm -2 ~7×10 15 N·cm -2 .
[0008] Preferably, the mass ratio of the polymer resin, barium sulfate and dispersant is (70~85):(25~35):(1~3).
[0009] Preferably, the mass ratio of the polymer resin, silica and coupling agent is (85~90):(8~12):(1~2).
[0010] Preferably, the mass ratio of barium sulfate in the barium sulfate composite material to silica in the silica composite material is (2:1)~(1:2).
[0011] Preferably, the particle size of barium sulfate is 0.5~3 μm, and the particle size of the silica is 1~5 μm.
[0012] Preferably, the polymer resin is polyethylene terephthalate or polybutylene terephthalate.
[0013] Preferably, the dispersant is one or more of montan wax, polyethyleneimine, polyacrylamide, polyvinyl alcohol, polypropylene ether; the coupling agent is one or more of aluminate coupling agent, titanate coupling agent, zirconium coupling agent, aluminum-titanium composite coupling agent, aluminum-zirconate coupling agent, silane coupling agent.
[0014] Preferably, the extrusion process uses a twin-screw extrusion process. The rotational speed of the main motor of the extrusion screw extruder is 250 - 350 r / min, the feeding speed is 12 - 18 kg / h, and the process temperatures of each zone from the screw inlet to the die of the extruder are as follows: the temperature of zone 1 is 260 - 280 °C, the temperature of zone 2 is 260 - 280 °C, the temperature of zone 3 is 260 - 280 °C, the temperature of zone 4 is 240 - 280 °C, the temperature of zone 5 is 200 - 240 °C, the temperature of zone 6 is 180 - 220 °C, the temperature of zone 7 is 180 - 220 °C, the temperature of zone 8 is 180 - 220 °C, the temperature of zone 9 is 180 - 220 °C, the temperature of zone 10 is 180 - 220 °C, the temperature of zone 11 is 200 - 240 °C, and the die temperature is 240 - 265 °C.
[0015] A modified polyester film obtained by the above preparation method.
[0016] An application of the modified polyester film in the preparation of biaxially oriented polyester films, degradable packaging films, and medical dialysis membranes.
[0017] The beneficial effects of the present invention are as follows: The present invention utilizes the microscopic rough surface characteristics of silica to improve the anti-blocking performance of the film. The silica is modified by nitrogen doping through low-temperature plasma discharge treatment, and amino groups (-NH2) are introduced onto the silica surface through a nitrogen-containing gas. Amino groups are prone to form hydrogen bonds with polymer chains. Through hydrogen bond action, the dispersibility of silica in the film can be improved, reducing light scattering caused by agglomeration, thereby reducing the haze of the film and increasing the light transmittance; by utilizing the refractive index matching of barium sulfate and polyester, the light transmittance is further increased and the haze is reduced. Through the synergistic effect of the two, the balance between high light transmittance and high anti-blocking performance of the polyester film is achieved. Specific embodiments
[0018] The present invention will be specifically introduced below in combination with specific embodiments.
[0019] Example 1. A preparation method of a modified polyester film includes the following specific steps:
[0020] S1. Preparation of barium sulfate composite material: 78 parts of PET resin, 30 parts of 0.5 μm barium sulfate, and 2 parts of polyethylene wax are blended and melt co-extruded to prepare a barium sulfate composite material; S2. Preparation of silica composite material: 10 parts of 1 μm silica is subjected to low-temperature plasma discharge treatment in an inert gas atmosphere at a temperature of 45 °C, a working voltage of -60 kV, a nitrogen injection dose of 6×10 15 N·cm -2 , and the discharge time is 35 min to obtain nitrogen-doped silica; the modified nitrogen-doped silica, 88.5 parts of high molecular polymer resin, and 1.5 parts of KH-550 are blended and melt co-extruded to prepare a silica composite material; S3. Preparation of modified polyester film: Take 3.33 parts of barium sulfate composite material and 10 parts of silicon dioxide composite material and mix them, that is, barium sulfate: silicon dioxide in the film is 1:1. After casting and biaxial stretching, a 50-μm polyester film is obtained.
[0021] Example 2. The difference between this example and Example 1 is that: 6.67 parts of barium sulfate composite material and 10 parts of silicon dioxide composite material, that is, barium sulfate: silicon dioxide in the film is 2:1. The remaining preparation processes are the same as those in Example 1.
[0022] Example 3. The difference between this example and Example 1 is that: adjust 10 parts of barium sulfate composite material and 10 parts of silicon dioxide composite material, that is, barium sulfate: silicon dioxide in the film is 3:1. The remaining preparation processes are the same as those in Example 1.
[0023] Example 4. The difference between this example and Example 1 is that: adjust 3.33 parts of barium sulfate composite material and 20 parts of silicon dioxide composite material, that is, barium sulfate: silicon dioxide in the film is 1:2. The remaining preparation processes are the same as those in Example 1.
[0024] Example 5. The difference between this example and Example 1 is that: adjust 3.33 parts of barium sulfate composite material and 30 parts of silicon dioxide composite material, that is, barium sulfate: silicon dioxide in the film is 1:3. The remaining preparation processes are the same as those in Example 1.
[0025] Comparative Example 1. The difference between this comparative example and Example 1 is that: adjust 10 parts of barium sulfate composite material, and the remaining preparation processes are the same as those in Example 1.
[0026] Comparative Example 2. The difference between this example and Example 1 is that: adjust 10 parts of silicon dioxide composite material, and the remaining preparation processes are the same as those in Example 1.
[0027] Comparative Example 3. The difference between this example and Example 1 is that: silicon dioxide is not modified, and the remaining preparation processes are the same as those in Example 1.
[0028] Performance detection test (1) Detection of light transmittance, haze and dynamic friction coefficient of the film: Respectively detect the light transmittance, haze and dynamic friction coefficient of the films prepared in Examples 1-5 and Comparative Examples 1-3. Detection method: Test the light transmittance and haze according to GB / T 2410-2008 "Determination of Light Transmittance and Haze of Transparent Plastics"; test the dynamic friction coefficient according to ASTM D1894 standard. The specific results are shown in Table 1.
[0029] Table 1 Performance of the films prepared in Examples 1-5 and Comparative Examples 1-3
[0030] As can be seen from Table 1, with the increase of the barium sulfate content in the film, the light transmittance will increase to some extent. This is because the refractive index of barium sulfate is similar to that of polyester and does not affect the light propagation effect. With the increase of the silica content, the haze will first increase and then decrease. This may be because the particle size of silica is small, and with the increase of the content, it is difficult to disperse, and agglomeration occurs during the preparation process, thus affecting the haze performance. Therefore, the optimal mass range of barium sulfate and silica is 2:1 to 1:2. From Example 1 and Comparative Example 1, it can be seen that when barium sulfate is used alone, the dynamic friction coefficient of the film is relatively low, and the opening effect is insufficient due to the lack of surface roughness control. From Example 1 and Comparative Example 2, it can be seen that although the use of silica alone can improve the opening property through the microscopic rough structure, its agglomeration behavior will cause a significant increase in haze, which is consistent with the coupling effect law of the dispersibility of nanoparticles on optical-mechanical properties.
[0031] The comparison between Example 1 and Comparative Example 3 shows that although the introduction of unmodified silica increases the dynamic friction coefficient of the film, it simultaneously shows the characteristics of high haze and low light transmittance. This phenomenon is mainly attributed to the agglomeration behavior of unmodified silica particles in the polyester matrix, resulting in uneven dispersion, increasing the haze of the film and decreasing the light transmittance. It can be seen from this that in the present invention, barium sulfate and silica are used synergistically as an anti-blocking agent, and the prepared film has good anti-blocking effect and optical effect at the same time.
[0032] (2) Influence of the particle size of barium sulfate on the film properties: The particle sizes of barium sulfate in Example 1 were respectively adjusted to 0.5, 1, 2, and 3 μm, and the specific results are shown in Table 2.
[0033] Table 2 Influence of the particle size of barium sulfate on the film properties
[0034] As can be seen from Table 2, adjusting the particle size of barium sulfate has a greater influence on the light transmittance. With the increase of the particle size of barium sulfate, the light transmittance will increase accordingly. This is because with the increase of the particle size, the specific surface area decreases, reducing scattering.
[0035] (3) Influence of the particle size of silica on the film properties: The particle sizes of silica in Example 1 were respectively adjusted to 1, 3, 5, and 7 μm, and the specific results are shown in Table 3.
[0036] Table 3 Influence of the particle size of silica on the film properties
[0037] As can be seen from Table 3, with the increase in the particle size of silica, the dynamic friction coefficient and haze increase. This may be because large particle size silica particles will form a more significant uneven structure on the film surface, increasing the surface roughness of the film.
[0038] (4)Effect of Nitrogen Injection Dose on the Properties of Films Prepared from Nitrogen-Modified Silica Through a plasma-based ion implantation (PBII) device, under the conditions of working voltages of -60 kV and nitrogen injection doses of 4×10 15 N·cm -2 、5×10 15 N·cm -2 、6×10 15 N·cm -2 、7×10 15 N·cm -2 、8×10 15 N·cm -2 silica was doped and modified. Then, the modified nitrogen-doped silica was used to prepare films. The specific steps were as in Example 1. The properties of the films prepared under different nitrogen injection doses were compared. The specific results are shown in Table 4.
[0039] Table 4 Effect of Nitrogen Injection Dose on the Properties of Films Prepared from Nitrogen-Modified Silica
[0040] As can be seen from Table 4, the transmittance first increases and then decreases with the increase in the nitrogen injection dose, and the haze first decreases and then increases with the increase in the nitrogen injection dose, reaching the best value at 6×10 15 N·cm -2 . This is because when the nitrogen injection dose is low, the amount of nitrogen doping is insufficient, the coverage rate of amino groups (-NH2) on the silica surface is low, the particle dispersion is poor, and aggregation leads to enhanced light scattering, resulting in a higher haze and a lower transmittance. With the increase in the nitrogen dose, amino groups are fully introduced, the interfacial binding with polyester is enhanced through hydrogen bonds, aggregation is inhibited, light scattering is reduced, the haze decreases, and the transmittance is significantly improved. When the dose is too high, excessive input of plasma energy will damage the silica lattice, form surface defects or secondary aggregation, light scattering is enhanced again, the haze increases, and the transmittance decreases.
[0041] The dynamic friction coefficient first decreases and then increases with the increase of nitrogen injection dose. When the nitrogen injection dose is low, the surface modification of silica is insufficient, the particle dispersibility is poor, the surface roughness distribution of the film is uneven, and the friction coefficient is high. With the increase of nitrogen dose, nitrogen doping optimizes the dispersion degree and surface roughness of silica particles, forming a uniform micro-protrusion structure, which not only improves the opening property but also avoids local stress concentration. When the dose is too high, over-modification may damage the surface morphology of silica, resulting in the sharpening of particle edges or the increase of aggregates, and the friction coefficient rebounds. It can be seen that the optimal nitrogen injection dose is 6×10 15 N·cm -2 ~7×10 15 N·cm -2 At this time, the light transmittance, haze and dynamic friction coefficient all reach the optimal balance, verifying the regulation effect of nitrogen doping modification on the dispersion and surface morphology of silica.
Claims
1. A method for preparing a modified polyester film, characterized in that, It includes the following specific steps: S1. Prepare barium sulfate composite material: Blend, melt and co-extrude a polymer resin, barium sulfate and a dispersant to prepare a barium sulfate composite material; S2. Prepare silica composite material: Carry out nitrogen doping modification treatment on silica, blend, melt and co-extrude the modified silica, polymer resin and coupling agent to prepare a silica composite material; S3. Prepare a modified polyester film: Mix the barium sulfate composite material and the silica composite material, extrude and stretch to obtain a modified polyester film.
2. The preparation method of a modified polyester film according to claim 1, characterized in that, The specific method for carrying out nitrogen doping modification treatment on silica is: Carry out low-temperature plasma discharge treatment on silica in an inert gas atmosphere to obtain nitrogen-doped silica.
3. The preparation method of a modified polyester film according to claim 2, characterized in that, The temperature of the low-temperature plasma discharge treatment is 40~50 °C, the working voltage is -40~-60 kV, and the nitrogen injection dose is 6×10 15 N·cm -2 ~7×10 15 N·cm -2 .
4. The preparation method of a modified polyester film according to claim 1, characterized in that, The mass ratio of the polymer resin, barium sulfate and dispersant is (70~85):(25~35):(1~3).
5. The preparation method of a modified polyester film according to claim 1, characterized in that, The mass ratio of the polymer resin, silica and coupling agent is (85~90):(8~12):(1~2).
6. The preparation method of a modified polyester film according to claim 1, characterized in that, The mass ratio of barium sulfate in the barium sulfate composite material to silica in the silica composite material is (2:1)~(1:2).
7. The preparation method of a modified polyester film according to claim 1, characterized in that, The particle size of the barium sulfate is 0.5~3 μm, and the particle size of the silica is 1~5 μm.
8. The preparation method of a modified polyester film according to claim 1, wherein, The polymer resin is polyethylene terephthalate or polybutylene terephthalate; the dispersant is one or more of montan wax, polyethyleneimine, polyacrylamide, polyvinyl alcohol, polypropylene ether; the coupling agent is one or more of aluminate coupling agent, titanate coupling agent, zirconium coupling agent, aluminum-titanium composite coupling agent, aluminum zirconate coupling agent, silane coupling agent.
9. A modified polyester film obtained by the preparation method according to claim 1.
10. Use of the modified polyester film according to claim 9 in the preparation of biaxially oriented polyester films, biodegradable packaging films, and medical dialysis membranes.