High-light-transmittance polyester film for automobile heat insulation film and preparation method of high-light-transmittance polyester film

Abstract

The invention relates to a high-light-transmittance polyester film and a preparation method thereof, in particular to a high-light-transmittance polyester film for an automobile heat insulation film and a preparation method of the high-light-transmittance polyester film. The problems that an existing automobile heat insulation film is low in ultraviolet blocking efficiency and poor in infrared blocking performance are solved. The high-light-transmittance polyester film for the automobile heat insulation film is prepared from the following raw materials: terephthalic acid, ethylene glycol, nano titanium dioxide, germanium oxide and cobaltous acetate tetrahydrate. The invention belongs to the technical field of automobile heat insulation films.

Description

Technical Field

[0001] The invention relates to a high-light-transmittance polyester film and a preparation method thereof, and belongs to the technical field of automobile heat-insulating films. Background Art

[0002] The development of automotive thermal insulation films can be traced back to the 1930s. It originated from military use and was initially applied to aircraft cockpit glass to protect against ultraviolet rays and heat. As technology evolved, it was gradually applied to the automotive field.

[0003] With the rapid development of materials science, new materials continue to emerge. For example, multi-layer polyester composite film, with its unique multi-layer structure, can more effectively reflect and absorb heat, significantly improving thermal insulation performance. Ceramic film uses the special optical properties of ceramic materials to achieve better light transmittance while insulating. The advent of these high-performance thermal insulation films not only greatly improves the thermal insulation effect, but also takes into account the performance improvements in light transmittance, privacy protection, and safety.

[0004] Market demand and technical pain points of automotive thermal insulation films

[0005] Climate and comfort requirements and technical challenges: Global climate conditions vary greatly, and in high-temperature areas, the demand for automotive insulation is extremely urgent. In hot weather, the temperature inside the car will rise sharply, which not only seriously affects the driving comfort, but also accelerates the aging process of the interior of the car. Although existing insulation films can block the heat of the sun to a certain extent, the insulation effect is still unsatisfactory in extremely high temperature environments and cannot fully meet users' expectations for a cool and comfortable environment in the car. At the same time, some insulation films sacrifice light transmittance to ensure the insulation effect, which affects the field of vision in the car and further reduces the driving experience. Especially at night or in low-light environments, poor light transmittance will make it difficult for drivers to observe road conditions and increase driving safety risks.

[0006] Demands for infrared and ultraviolet protection and technical limitations: The damage of infrared and ultraviolet rays to human skin and car interiors cannot be ignored. Passengers are at risk of skin diseases due to long-term exposure to infrared and ultraviolet rays. At the same time, car seats, dashboards and other interior decorations are prone to fading and aging. Although the current thermal insulation film has a certain ability to block ultraviolet rays, it still needs to be improved in terms of blocking efficiency and infrared blocking properties, and it is difficult to protect the health of passengers and the interior of the car in an all-round way. Therefore, in this field, it is expected to develop a high-transmittance polyester film base film for automotive thermal insulation films, which can increase the visible light transmittance while blocking infrared and ultraviolet rays, effectively improving driving safety and comfort. Summary of the invention

[0007] The present invention aims to solve the problems of low ultraviolet blocking efficiency and poor infrared blocking performance of existing automobile thermal insulation films, and further proposes a high light transmittance polyester film for automobile thermal insulation film and a preparation method thereof.

[0008] The technical solution adopted by the present invention to solve the above problems is: the raw materials of the high light transmittance polyester film for automobile thermal insulation film described in the present invention include terephthalic acid, ethylene glycol, nano titanium dioxide, germanium oxide and cobalt acetate tetrahydrate.

[0009] Furthermore, the component ratio of each element in the raw material of the high-transmittance polyester film for automobile thermal insulation film is: 100 parts of terephthalic acid, 45-55 parts of ethylene glycol, 3-5 parts of nano titanium dioxide, 0.03-0.07 parts of germanium oxide, and 0.03-0.07 parts of cobalt acetate tetrahydrate.

[0010] Furthermore, the particle size of the nano titanium dioxide is less than 150 mm, the purity of the nano titanium dioxide is greater than 99.5%, and the crystal form of the nano titanium dioxide is rutile.

[0011] Furthermore, the particle size of the germanium oxide is less than 75 μm, and the purity of the germanium oxide is greater than 99.99%.

[0012] Furthermore, the purity of cobalt acetate tetrahydrate is greater than 99.9%.

[0013] The method for preparing a highly light-transmitting polyester film for automobile thermal insulation film of the present invention comprises the following steps:

[0014] Step 1, adding terephthalic acid, ethylene glycol, nano titanium dioxide, germanium oxide, and cobalt acetate tetrahydrate into a reaction kettle, and exhausting nitrogen to remove air;

[0015] Step 2, adding nitrogen until the pressure in the reactor reaches 90-150 kPa;

[0016] Step 3, stirring and rapidly heating to 210-230° C., and the pressure reaches 340-360 kPa;

[0017] Step 4, start the esterification reaction while maintaining stirring and release the pressure, and reduce the pressure to 0 kPa within 110 to 130 minutes;

[0018] Step 5, under the protection of nitrogen atmosphere, stirring and heating to 270-290°C;

[0019] Step 6: Use a vacuum pump to make the pressure in the reactor reach an absolute pressure of 150-80 Pa within 50-70 minutes;

[0020] Step 7, maintaining the vacuum degree until the intrinsic viscosity of the product at the end of the polycondensation is ≥0.7 dL / g, keeping the heating off, stirring, introducing nitrogen to press out the product, and letting the product flow into pure water for drawing to obtain a strand;

[0021] Step 8: pelletize and dry the strands, and then form a film through biaxial stretching to obtain a highly light-transmitting PET film base film for automotive thermal insulation film.

[0022] Furthermore, in step 7, the temperature of the pure water is 0-10°C.

[0023] Furthermore, in step 8, the thickness of the film is 25 to 150 μm.

[0024] The beneficial effects of the present invention are as follows: the raw materials for preparing the polyester provided by the present invention contain nano titanium dioxide, germanium oxide and cobalt acetate tetrahydrate, and the three act synergistically, so that the prepared polyester film has higher visible light transmittance, lower haze and stronger infrared and ultraviolet light blocking properties, and the polyester film is used as a car heat insulation film to solve the problem that ordinary polyester films have low light transmittance and high infrared and ultraviolet light transmittances leading to increased temperature inside the car, thereby improving the comfort and safety of driving and riding in the car. Example

[0025] The information of some raw materials used in the examples and comparative examples of the present invention is as follows:

[0026] Nano titanium dioxide: average particle size 100nm, brand T104945;

[0027] Germanium oxide: average particle size 75μm, brand G105882;

[0028] Cobalt acetate tetrahydrate: brand number is C110803.

[0029] Example 1

[0030] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 3 parts of nano titanium dioxide, 0.03 parts of germanium oxide, and 0.03 parts of cobalt acetate tetrahydrate.

[0031] The preparation method comprises the following steps:

[0032] The above-mentioned raw materials are added into a polyester special reactor, and nitrogen is passed through three times to remove air; nitrogen is added until the pressure in the reactor reaches 120 kPa; the temperature is rapidly raised to 220°C and the pressure reaches 350 kPa while stirring; the esterification reaction is started while the pressure is slowly released while stirring, and the pressure is reduced to 0 kPa within 120 minutes; under the protection of a nitrogen atmosphere, the temperature is rapidly raised to 280°C; a vacuum pump is used to make the pressure in the reactor reach an absolute pressure of 80 Pa within 60 minutes; the vacuum degree is maintained until the intrinsic viscosity at the end of the polycondensation is ≥0.7 dL / g, the heating is kept turned off while stirring, nitrogen is passed through to extrude the product, and the product flows into 0°C pure water for drawing; the wire material is granulated and dried, and a film with a thickness of 4 microns is prepared through biaxial stretching to obtain the polyester film.

[0033] Example 2

[0034] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 5 parts of nano titanium dioxide, 0.07 parts of germanium oxide, and 0.07 parts of cobalt acetate tetrahydrate.

[0035] The preparation method comprises the following steps:

[0036] The above-mentioned raw materials are added into a polyester special reactor, and nitrogen is discharged three times to remove air; nitrogen is added until the pressure in the reactor reaches 90 kPa; the temperature is rapidly raised to 210°C and the pressure reaches 340 kPa while stirring; the esterification reaction is started while the pressure is slowly released while stirring, and the pressure is reduced to 0 kPa within 110 minutes; under the protection of a nitrogen atmosphere, the temperature is rapidly raised to 270°C; a vacuum pump is used to make the pressure in the reactor reach an absolute pressure of 150 Pa within 50 minutes; the vacuum degree is maintained until the intrinsic viscosity at the end of the polycondensation is ≥0.7 dL / g, the heating is kept turned off while stirring, nitrogen is introduced to extrude the product, and the product flows into 10°C pure water for drawing; the wire material is granulated and dried, and a film with a thickness of 4 microns is prepared through biaxial stretching to obtain the polyester film.

[0037] Example 3

[0038] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 4 parts of nano titanium dioxide, 0.05 parts of germanium oxide, and 0.05 parts of cobalt acetate tetrahydrate.

[0039] The preparation method comprises the following steps:

[0040] The above-mentioned raw materials are added into a polyester special reactor, and nitrogen is discharged three times to remove air; nitrogen is added until the pressure in the reactor reaches 150 kPa; the temperature is quickly raised to 230°C and the pressure reaches 360 kPa while stirring; the esterification reaction is started while stirring and the pressure is slowly released to reduce the pressure to 0 kPa within 130 minutes; under the protection of a nitrogen atmosphere, the temperature is quickly raised to 290°C; a vacuum pump is used to make the pressure in the reactor reach an absolute pressure of 100 Pa within 70 minutes; the vacuum degree is maintained until the intrinsic viscosity at the end of the polycondensation is ≥0.7 dL / g, the heating is kept turned off and the stirring is turned off, nitrogen is introduced to extrude the product, and the product flows into 5°C pure water for drawing; the wire material is granulated and dried, and a film with a thickness of 4 microns is prepared through biaxial stretching to obtain the polyester film.

[0041] Example 4

[0042] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 3 parts of nano titanium dioxide, 0.07 parts of germanium oxide, and 0.03 parts of cobalt acetate tetrahydrate.

[0043] The preparation method is as in Example 1.

[0044] Example 5

[0045] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 4 parts of nano titanium dioxide, 0.03 parts of germanium oxide, and 0.07 parts of cobalt acetate tetrahydrate.

[0046] The preparation method is as in Example 1.

[0047] Example 6

[0048] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 5 parts of nano titanium dioxide, 0.06 parts of germanium oxide, and 0.04 parts of cobalt acetate tetrahydrate.

[0049] The preparation method is as in Example 1.

[0050] Comparative Example 1

[0051] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 0.03 parts of germanium oxide, and 0.07 parts of cobalt acetate tetrahydrate.

[0052] The preparation method is as in Example 1.

[0053] Comparative Example 2

[0054] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 4 parts of nano titanium dioxide, and 0.07 parts of cobalt acetate tetrahydrate.

[0055] The preparation method is as in Example 1.

[0056] Comparative Example 3

[0057] In this embodiment, a polyester film is provided. The raw materials for preparing the polyester film include the following components in parts by weight: 100 parts of terephthalic acid, 50 parts of ethylene glycol, 4 parts of nano titanium dioxide, and 0.03 parts of germanium oxide.

[0058] The preparation method is as in Example 1.

[0059] The polyester films provided in the examples and comparative examples were subjected to performance tests, and the test methods were as follows:

[0060] (1) Total transmittance / haze test: The film was melted and hot-pressed at 280°C using a stainless steel mold, and then quenched in ice water to form a film with a thickness of 1 mm. After vacuum drying at 40°C for 5 hours, it was pressed at a pressure of 5 MPa for 10 minutes using a sapphire flat mold in a flat vulcanizer preheated to 80°C, and naturally cooled to room temperature under this pressure to obtain a polyester optical performance test film with a high-precision optical plane. The total transmittance and haze test were performed using a WGT-2S transmittance / haze tester at 25°C, C light source mode.

[0061] (2) Full spectrum transmittance test The copolyester was dried at 40°C for 8 h, and the transmittance in the wavelength range of 200 nm to 1000 nm was tested at 25°C using a UV-3600 ultraviolet-visible-near infrared spectrophotometer (Shimadzu, Japan), with a wavelength interval of 0.5 nm.

[0062] The performance test results are shown in Table 1.

[0063] Table 1

[0064] Light transmittance / % Haze / % Infrared blocking rate / % UV blocking rate / % Example 1 90.9 5.2 90.0 92.0 Example 2 89.8 3.2 91.1 91.9 Example 3 88.3 3.9 90.2 91.8 Example 4 89.5 4.6 90.2 92.6 Example 5 90.0 4.8 91.4 93.2 Example 6 91.6 3.6 92.5 94.8 Comparative Example 1 90.3 3.0 87.5 90.6 Comparative Example 2 87.3 4.4 89.3 91.6 Comparative Example 3 89.2 4.6 90.5 90.4 Conventional example 87.3 8.7 80.7 85.2

[0065] It can be seen from Table 1 that the synergistic effect of nano titanium dioxide, germanium oxide and cobalt acetate tetrahydrate can effectively improve the light transmittance, infrared blocking rate and ultraviolet blocking rate of the film, and can reduce the haze, indicating that the thermal insulation effect of the film can indeed be improved, and it can be beneficial to improve the driving experience of the car.

[0066] In summary, the automotive thermal insulation film made of the polyester film provided by the invention can meet the work and use requirements in the field of automotive thermal insulation films, and effectively improves the driving experience of the car, improves the clarity of the windows, and reduces the temperature inside the car.

[0067] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A highly light-transmitting polyester film for automotive thermal insulation film, characterized in that: The raw materials of the high-light-transmittance polyester film for automobile thermal insulation film include terephthalic acid, ethylene glycol, nano titanium dioxide, germanium oxide and cobalt acetate tetrahydrate.

2. The highly light-transmitting polyester film for automobile thermal insulation film according to claim 1, characterized in that: The component ratio of each element in the raw material of the high-light-transmittance polyester film for automobile thermal insulation film is: 100 parts of terephthalic acid, 45-55 parts of ethylene glycol, 3-5 parts of nano titanium dioxide, 0.03-0.07 parts of germanium oxide, and 0.03-0.07 parts of cobalt acetate tetrahydrate.

3. The highly light-transmitting polyester film for automobile thermal insulation film according to claim 1, characterized in that: The particle size of the nano titanium dioxide is less than 150 mm, the purity of the nano titanium dioxide is greater than 99.5%, and the crystal form of the nano titanium dioxide is rutile.

4. The highly light-transmitting polyester film for automobile thermal insulation film according to claim 1, characterized in that: The particle size of the germanium oxide is less than 75 μm, and the purity of the germanium oxide is greater than 99.99%.

5. The highly light-transmitting polyester film for automobile thermal insulation film according to claim 1, characterized in that: The purity of cobalt acetate tetrahydrate is greater than 99.9%.

6. A method for preparing a highly transparent polyester film for automobile thermal insulation film, characterized in that: The specific steps include: Step 1, adding terephthalic acid, ethylene glycol, nano titanium dioxide, germanium oxide, and cobalt acetate tetrahydrate into a reaction kettle, and exhausting nitrogen to remove air; Step 2, adding nitrogen until the pressure in the reactor reaches 90-150 kPa; Step 3, stirring and rapidly heating to 210-230° C., and the pressure reaches 340-360 kPa; Step 4, start the esterification reaction while maintaining stirring and release the pressure, and reduce the pressure to 0 kPa within 110 to 130 minutes; Step 5, under the protection of nitrogen atmosphere, stirring and heating to 270-290°C; Step 6: Use a vacuum pump to make the pressure in the reactor reach an absolute pressure of 150-80 Pa within 50-70 minutes; Step 7, maintaining the vacuum degree until the intrinsic viscosity of the product at the end of the polycondensation is ≥0.7 dL / g, keeping the heating off, stirring, introducing nitrogen to press out the product, and letting the product flow into pure water for drawing to obtain a strand; Step 8: pelletize and dry the strands, and then form a film through biaxial stretching to obtain a highly light-transmitting PET film base film for automotive thermal insulation film.

7. The method for preparing a highly light-transmitting polyester film for automobile thermal insulation film according to claim 6, characterized in that: The temperature of the pure water in step 7 is 0-10°C.

8. The method for preparing a highly light-transmitting polyester film for automobile thermal insulation film according to claim 6, characterized in that: The thickness of the film in step 8 is 25 to 150 μm.