A high-temperature resistant PET composite release film and its preparation method

Abstract

This invention discloses a high-temperature resistant PET composite release film and its preparation method, belonging to the field of release film technology. The method includes the following steps: corona-treating one side of a PET substrate, cleaning, and drying to obtain a pretreated PET substrate; coating the corona-treated surface of the pretreated PET substrate with a heat-resistant coating, curing, slitting, and winding to obtain the high-temperature resistant PET composite release film; the heat-resistant coating comprises hyperbranched epoxy resin and epoxy-based silane coupling agent-modified silica-coated carbon nanotubes; by coating the corona-treated side surface of the PET substrate with a heat-resistant coating, the high-temperature resistance of the PET composite release film is improved, its heat stability is enhanced, and delamination and blistering under high-temperature conditions are avoided.

Description

Technical Field

[0001] This invention belongs to the field of release film technology, specifically relating to a high-temperature resistant PET composite release film and its preparation method. Background Technology

[0002] In the manufacturing of printed circuit boards, ceramic electronic components, etc., release films are often sandwiched between metal plates or resins during the process to prevent adhesion between the metal plates or resins. These processes all need to be completed under certain high temperature conditions.

[0003] Release films, in a general sense, include fluoropolymer films such as Teflon, polyolefin films, and films coated with silicone materials on the surface of biaxially stretched polyethylene terephthalate (PET). Among these, fluoropolymer films, used as surface layers, possess excellent heat resistance and release properties, giving release films exceptional performance. However, the technology for producing fluoropolymer release films in China is still immature, with most production relying on imports due to the high cost of raw materials. This high cost hinders the widespread adoption of fluoropolymer release films in electronic product manufacturing. Release films coated with silicone oil on the PET surface are prone to silicone oil residue, leading to instability and high scrap rates in later use. Therefore, developing a new type of release film material that combines excellent heat resistance and release properties with controllable cost and no residue issues to overcome the shortcomings of traditional products and meet the increasingly stringent application requirements of the electronics industry is crucial. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature resistant PET composite release film and its preparation method. By coating the corona-side surface of the PET substrate with a heat-resistant coating, the problem of poor heat resistance and easy detachment and blistering of PET release films in the prior art can be solved.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a high-temperature resistant PET composite release film includes the following steps:

[0007] S1. One side of the PET substrate is corona treated, then the substrate surface is cleaned with deionized water and dried with hot air at 45-55℃ for 1-2 hours to obtain the pretreated PET substrate.

[0008] S2. Coat the corona-treated PET substrate with a heat-resistant coating, cure, cut, and roll up to obtain the high-temperature resistant PET composite release film.

[0009] The heat-resistant coating comprises hyperbranched epoxy resin and epoxy silane coupling agent modified silica coated carbon nanotubes.

[0010] The epoxy silane coupling agent is selected from any one of KH560, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and silane coupling agent A-186.

[0011] As a preferred embodiment of the present invention, the process parameters of the corona treatment are: operating frequency 15-25kHz, power 8-10kW, processing speed 10-20m / min, and electrode spacing 1-2mm.

[0012] As a preferred embodiment of the present invention, the coating speed of the coating machine is 10-20 m / min, and the coating thickness is 5-10 μm.

[0013] As a preferred embodiment of the present invention, the method for preparing the hyperbranched epoxy resin includes the following steps:

[0014] A1. Mix 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine, and reflux at 80-90℃ for 10-15 hours. Wash the precipitate with ether and deionized water, repeat three times, and then dry the product in a vacuum oven at 80℃ for 12 hours after rotary evaporation for 30 minutes to obtain branched epoxy resin.

[0015] A2. In a nitrogen atmosphere, the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran and deionized water are mixed and refluxed at 80-90°C for 7-9 hours. The product is then rotary evaporated for 30 minutes and dried in a vacuum oven at 80°C for 12 hours to obtain the hyperbranched epoxy resin.

[0016] As a preferred embodiment of the present invention, in step A1, the mass ratio of 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine is 1.5-2.5:7-9:0.1-0.2.

[0017] As a preferred embodiment of the present invention, in step A2, the mass ratio of the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran and deionized water is 1:1.2-1.4:0.03-0.05:10-15:8-10.

[0018] As a preferred embodiment of the present invention, the method for preparing epoxy-silane coupling agent modified silica-coated carbon nanotubes includes the following steps:

[0019] B1. Multi-walled carbon nanotubes are subjected to mixed acid oxidation treatment to obtain pretreated multi-walled carbon nanotubes;

[0020] The mixed acid comprises concentrated sulfuric acid and concentrated nitric acid, wherein the concentration of concentrated sulfuric acid is 70.0-98.3 wt%, the concentration of concentrated nitric acid is 68-98 wt%, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1.

[0021] The oxidation treatment is carried out at a temperature of 40-60℃ for 6-8 hours.

[0022] It also includes washing and drying the obtained pretreated multi-walled carbon nanotubes, drying them at 50-70℃ until the moisture evaporates completely;

[0023] The ratio of the multi-walled carbon nanotubes to the mixed acid solution is 1g:150-250mL;

[0024] B2. Take the pretreated multi-walled carbon nanotubes and deionized water, mix them, and ultrasonically disperse them for 1-2 hours. Add anhydrous ethanol, ultrasonically stir for 20-30 minutes, adjust the pH to 8-9 with 1 mol / L ammonia water, add tetraethyl orthosilicate, stir at 50-60℃ for 10-15 hours, filter, take the solid phase, wash and dry to obtain silica-coated carbon nanotubes.

[0025] B3. Take the silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water, mix them, ultrasonically disperse them for 1-2 hours, heat and stir at 60°C for 4-8 hours, filter them, take the solid phase, wash and dry them to obtain the epoxy silane coupling agent modified silica-coated carbon nanotubes.

[0026] As a preferred embodiment of the present invention, in step B2, the ratio of the pretreated multi-walled carbon nanotubes, deionized water, anhydrous ethanol, and tetraethyl orthosilicate is 2-3g: 150-250mL: 100-200mL: 4.5-5.5g.

[0027] As a preferred embodiment of the present invention, in step B3, the ratio of silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water is 1.2-1.6g: 50-80mL: 3-5mL: 40-60mL.

[0028] The beneficial effects of this invention are:

[0029] This invention improves the high-temperature resistance and thermal stability of PET composite release films by coating the corona-side surface of PET substrates with a heat-resistant coating, thus preventing delamination and blistering under high-temperature conditions. By preparing hyperbranched epoxy resin, the rigid benzene rings inhibit the thermal movement of molecular chains at high temperatures, reducing thermal expansion and thermo-oxidative degradation. The hyperbranched structure avoids long-range entanglement of linear molecular chains, and the numerous terminal epoxy groups can fully react with the curing agent to form a dense three-dimensional cross-linked network, ensuring a tight bond between the coating and the PET substrate. This restricts the movement of molecular chains at high temperatures, reducing thermal shrinkage or cracking of the coating. Furthermore, by adding an epoxy-based silane coupling agent, silica-coated carbon nanotubes react with the terminal epoxy groups of the hyperbranched epoxy resin or the curing agent, localized high temperatures can be rapidly dispersed throughout the coating, preventing localized overheating and resin decomposition. Simultaneously, the carbon nanotubes entangle with the hyperbranched epoxy resin cross-linked network, preventing cracking and peeling of the coating at high temperatures, indirectly contributing to improved thermal stability. Detailed Implementation

[0030] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below. Example

[0031] A method for preparing a high-temperature resistant PET composite release film includes the following steps:

[0032] S1. One side of the PET substrate is subjected to corona treatment, then the substrate surface is cleaned with deionized water and dried with hot air at 45°C for 1 hour to obtain the pretreated PET substrate; the process parameters of the corona treatment are: working frequency 15kHz, power 8kW, processing speed 10m / min, and electrode spacing 1mm.

[0033] S2. Coat the corona-treated PET substrate with a heat-resistant coating. The coating speed of the coating machine is 10m / min and the coating thickness is 5μm. After coating, cure and dry at 60℃ for 8h, then cut and roll up to obtain the high-temperature resistant PET composite release film.

[0034] The method for preparing the heat-resistant coating includes the following steps:

[0035] M1. Mix 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine, reflux and stir at 80°C for 10 h, wash the precipitate with diethyl ether and deionized water, repeat three times, rotary evaporate the product for 30 min, and then dry it in a vacuum oven at 80°C for 12 h to obtain branched epoxy resin; the mass ratio of 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine is 1.5:7:0.1;

[0036] M2. Under a nitrogen atmosphere, the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water were mixed and refluxed at 80°C for 7 hours. The product was then rotary evaporated for 30 minutes and dried in a vacuum oven at 80°C for 12 hours to obtain a hyperbranched epoxy resin. The mass ratio of the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water was 1:1.2:0.03:10:8.

[0037] M3. Multi-walled carbon nanotubes are subjected to mixed acid oxidation treatment to obtain pretreated multi-walled carbon nanotubes.

[0038] The mixed acid comprises concentrated sulfuric acid and concentrated nitric acid, wherein the concentration of concentrated sulfuric acid is 98.3 wt%, the concentration of concentrated nitric acid is 98 wt%, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1.

[0039] The oxidation treatment was performed at a temperature of 40°C for 6 hours.

[0040] It also includes washing and drying the obtained pretreated multi-walled carbon nanotubes, drying them at 50°C until the moisture evaporates completely;

[0041] The ratio of the multi-walled carbon nanotubes to the mixed acid solution is 1g:150mL;

[0042] M4. Take the pretreated multi-walled carbon nanotubes and deionized water, mix them, and ultrasonically disperse them for 1 hour. Add anhydrous ethanol, ultrasonically stir for 20 minutes, adjust the pH to 8 with 1 mol / L ammonia, add tetraethyl orthosilicate, stir at 50°C for 10 hours, filter, wash the solid phase, and dry to obtain silica-coated carbon nanotubes; the ratio of the pretreated multi-walled carbon nanotubes, deionized water, anhydrous ethanol, and tetraethyl orthosilicate is 2 g: 150 mL: 100 mL: 4.5 g;

[0043] M5. Take the silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water, mix them, ultrasonically disperse them for 1 hour, heat and stir at 60°C for 4 hours, filter them, take the solid phase, wash and dry them to obtain epoxy silane coupling agent modified silica-coated carbon nanotubes; the ratio of silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water is 1.2g:50mL:3mL:40mL;

[0044] M6. Take the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant, mix them, and stir evenly to obtain the heat-resistant coating; the mass ratio of the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant is 35:5:2:0.4:0.5:0.5. Example

[0045] A method for preparing a high-temperature resistant PET composite release film includes the following steps:

[0046] S1. One side of the PET substrate is subjected to corona treatment, then the substrate surface is cleaned with deionized water and dried with hot air at 50°C for 1.5 hours to obtain the pretreated PET substrate; the process parameters of the corona treatment are: working frequency 20kHz, power 9kW, processing speed 15m / min, and electrode spacing 1.5mm.

[0047] S2. Coat the corona-treated PET substrate with a heat-resistant coating. The coating speed of the coating machine is 15m / min and the coating thickness is 8μm. After coating, cure and dry at 60℃ for 9h, then cut and roll up to obtain the high-temperature resistant PET composite release film.

[0048] The method for preparing the heat-resistant coating includes the following steps:

[0049] M1. Mix 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine, reflux at 85°C for 12 h, wash the precipitate with diethyl ether and deionized water, repeat three times, rotary evaporate the product for 30 min, and then dry it in a vacuum oven at 80°C for 12 h to obtain branched epoxy resin; the mass ratio of 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine is 2.0:8:0.15;

[0050] M2. Under a nitrogen atmosphere, the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water were mixed and refluxed at 85°C for 8 hours. The product was then rotary evaporated for 30 minutes and dried in a vacuum oven at 80°C for 12 hours to obtain hyperbranched epoxy resin. The mass ratio of the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water was 1:1.3:0.04:12:9.

[0051] M3. Multi-walled carbon nanotubes are subjected to mixed acid oxidation treatment to obtain pretreated multi-walled carbon nanotubes.

[0052] The mixed acid comprises concentrated sulfuric acid and concentrated nitric acid, wherein the concentration of concentrated sulfuric acid is 98.3 wt%, the concentration of concentrated nitric acid is 98 wt%, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1.

[0053] The oxidation treatment was carried out at a temperature of 50°C for 7 hours.

[0054] It also includes washing and drying the obtained pretreated multi-walled carbon nanotubes, drying them at 60°C until the moisture evaporates completely;

[0055] The ratio of the multi-walled carbon nanotubes to the mixed acid solution is 1g:200mL;

[0056] M4. Take the pretreated multi-walled carbon nanotubes and deionized water, mix them, and ultrasonically disperse them for 1.5 h. Add anhydrous ethanol, ultrasonically stir for 25 min, adjust the pH to 8.5 with 1 mol / L ammonia water, add tetraethyl orthosilicate, stir at 55℃ for 12 h, filter, take the solid phase, wash, and dry to obtain silica-coated carbon nanotubes; the ratio of the pretreated multi-walled carbon nanotubes, deionized water, anhydrous ethanol, and tetraethyl orthosilicate is 2.5 g: 200 mL: 150 mL: 5.0 g;

[0057] M5. Take the silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water, mix them, ultrasonically disperse them for 1.5 h, heat and stir at 60 °C for 4-8 h, filter, take the solid phase, wash and dry, to obtain epoxy silane coupling agent modified silica-coated carbon nanotubes; the ratio of silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water is 1.4 g: 65 mL: 4 mL: 50 mL;

[0058] M6. Take the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant, mix them, and stir evenly to obtain the heat-resistant coating; the mass ratio of the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant is 40:6:3:0.5:0.6:0.7. Example

[0059] A method for preparing a high-temperature resistant PET composite release film includes the following steps:

[0060] S1. One side of the PET substrate is subjected to corona treatment, then the substrate surface is cleaned with deionized water and dried with hot air at 55°C for 2 hours to obtain the pretreated PET substrate; the process parameters of the corona treatment are: working frequency 25kHz, power 10kW, processing speed 20m / min, and electrode spacing 2mm.

[0061] S2. Coat the corona-treated PET substrate with a heat-resistant coating. The coating speed of the coating machine is 20m / min and the coating thickness is 10μm. After coating, cure and dry at 60℃ for 10h, then cut and roll up to obtain the high-temperature resistant PET composite release film.

[0062] The method for preparing the heat-resistant coating includes the following steps:

[0063] M1. Mix 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine, reflux and stir at 90°C for 15 h, wash the precipitate with diethyl ether and deionized water, repeat three times, rotary evaporate the product for 30 min, and then dry it in a vacuum oven at 80°C for 12 h to obtain branched epoxy resin; the mass ratio of 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine is 2.5:9:0.2;

[0064] M2. Under a nitrogen atmosphere, the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water were mixed and refluxed at 90°C for 9 hours. The product was then rotary evaporated for 30 minutes and dried in a vacuum oven at 80°C for 12 hours to obtain hyperbranched epoxy resin. The mass ratio of the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water was 1:1.4:0.05:15:10.

[0065] M3. Multi-walled carbon nanotubes are subjected to mixed acid oxidation treatment to obtain pretreated multi-walled carbon nanotubes.

[0066] The mixed acid comprises concentrated sulfuric acid and concentrated nitric acid, wherein the concentration of concentrated sulfuric acid is 98.3 wt%, the concentration of concentrated nitric acid is 98 wt%, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1.

[0067] The oxidation treatment was carried out at a temperature of 60°C for 8 hours.

[0068] It also includes washing and drying the obtained pretreated multi-walled carbon nanotubes, drying them at 70°C until the moisture evaporates completely;

[0069] The ratio of the multi-walled carbon nanotubes to the mixed acid solution is 1g:250mL;

[0070] M4. Take the pretreated multi-walled carbon nanotubes and deionized water, mix them, and ultrasonically disperse them for 2 hours. Add anhydrous ethanol, ultrasonically stir for 30 minutes, adjust the pH to 9 with 1 mol / L ammonia, add tetraethyl orthosilicate, stir at 60°C for 15 hours, filter, wash the solid phase, and dry to obtain silica-coated carbon nanotubes; the ratio of the pretreated multi-walled carbon nanotubes, deionized water, anhydrous ethanol, and tetraethyl orthosilicate is 3 g: 250 mL: 200 mL: 5.5 g;

[0071] M5. Take the silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water, mix them, ultrasonically disperse them for 2 hours, heat and stir at 60°C for 8 hours, filter them, take the solid phase, wash and dry them to obtain epoxy silane coupling agent modified silica-coated carbon nanotubes; the ratio of silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water is 1.6g:80mL:5mL:60mL;

[0072] M6. Take the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant, mix them, and stir evenly to obtain the heat-resistant coating; the mass ratio of the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant is 45:7:4:0.6:0.7:0.9.

[0073] Comparative Example 1

[0074] The difference from Example 2 is that the preparation method of this PET composite release film includes the following steps:

[0075] S1. One side of the PET substrate is subjected to corona treatment, then the substrate surface is cleaned with deionized water and dried with hot air at 50°C for 1.5 hours to obtain the pretreated PET substrate; the process parameters of the corona treatment are: working frequency 20kHz, power 9kW, processing speed 15m / min, and electrode spacing 1.5mm.

[0076] S2. Coat the corona-treated PET substrate with epoxy resin coating. The coating speed of the coating machine is 15m / min and the coating thickness is 8μm. After coating, cure and dry at 60℃ for 9h, slit and roll up to obtain the high temperature resistant PET composite release film.

[0077] The preparation method of the epoxy resin coating includes the following steps:

[0078] The heat-resistant coating is obtained by mixing commercially available bisphenol A type epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant, and stirring evenly. The mass ratio of the bisphenol A type epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant is 40:6:3:0.5:0.6:0.7.

[0079] Comparative Example 2

[0080] The difference from Example 2 is that the preparation method of this PET composite release film includes the following steps:

[0081] S1. One side of the PET substrate is subjected to corona treatment, then the substrate surface is cleaned with deionized water and dried with hot air at 50°C for 1.5 hours to obtain the pretreated PET substrate; the process parameters of the corona treatment are: working frequency 20kHz, power 9kW, processing speed 15m / min, and electrode spacing 1.5mm.

[0082] S2. Coat the corona-treated PET substrate with epoxy resin coating. The coating speed of the coating machine is 15m / min and the coating thickness is 8μm. After coating, cure and dry at 60℃ for 9h, slit and roll up to obtain the high temperature resistant PET composite release film.

[0083] The preparation method of the epoxy resin coating includes the following steps:

[0084] The heat-resistant coating is obtained by mixing hyperbranched epoxy resin, multi-walled carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and dispersant BYK-220S, and stirring evenly. The mass ratio of the hyperbranched epoxy resin, multi-walled carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and dispersant BYK-220S is 40:6:3:0.5:0.6:0.7.

[0085] Comparative Example 3

[0086] The difference from Example 2 is that the preparation method of this high-temperature resistant PET composite release film includes the following steps:

[0087] S1. One side of the PET substrate is subjected to corona treatment, then the substrate surface is cleaned with deionized water and dried with hot air at 50°C for 1.5 hours to obtain the pretreated PET substrate; the process parameters of the corona treatment are: working frequency 20kHz, power 9kW, processing speed 15m / min, and electrode spacing 1.5mm.

[0088] S2. Coat the corona-treated PET substrate with a heat-resistant coating. The coating speed of the coating machine is 15m / min and the coating thickness is 8μm. After coating, cure and dry at 60℃ for 9h, then cut and roll up to obtain the high-temperature resistant PET composite release film.

[0089] The method for preparing the heat-resistant coating includes the following steps:

[0090] The branched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant are mixed and stirred evenly to obtain the heat-resistant coating; the mass ratio of the branched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant is 40:6:3:0.5:0.6:0.7.

[0091] Performance testing

[0092] The PET composite release films prepared in Examples 1-3 and Comparative Examples 1-3 were placed at 150℃ and 300℃ for 1 hour respectively for high temperature resistance test. The abnormal phenomena such as color spots and yellowing on the surface of the release film were observed. The test results are shown in Table 1 below.

[0093] The PET composite release films prepared in Examples 1-3 and Comparative Examples 1-3 were baked at 180°C for 60 minutes to conduct a thermal stability test. If there was no delamination, no blistering, and no bubbles, it indicates that the product performance is good. The test results are shown in Table 1 below.

[0094] Table 1

[0095]

[0096] As shown in Table 1, the PET composite release films prepared in Examples 1-3 of this application have better high-temperature resistance than the comparative examples, exhibit good thermal stability at higher temperatures, and can still maintain excellent product performance.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant PET composite release film, characterized in that, Includes the following steps: S1. One side of the PET substrate is corona treated, cleaned, and dried to obtain a pretreated PET substrate; S2. Coat the corona-treated PET substrate with a heat-resistant coating, cure, cut, and roll up to obtain the high-temperature resistant PET composite release film. The preparation method of the heat-resistant coating includes the following steps: The heat-resistant coating is obtained by mixing hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant, and stirring evenly. The mass ratio of the hyperbranched epoxy resin, epoxy silane coupling agent modified silica-coated carbon nanotubes, curing agent diethylenetriamine, dimethyl silicone oil defoamer, leveling agent BYK-310, and BYK-220S dispersant is 35-45:5-7:2-7:0.4-0.6:0.5-0.7:0.5-0.

9. The preparation method of the hyperbranched epoxy resin includes the following steps: A1. A branched epoxy resin was prepared by using 2,2-bis(4-hydroxyphenyl)propane and trimethylolpropane triglycidyl ether as raw materials under the catalysis of triethylamine. A2. In a nitrogen atmosphere, the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran and deionized water are mixed, refluxed and heated with stirring, and the product is evaporated and dried to obtain the hyperbranched epoxy resin. In step A1, the mass ratio of 2,2-bis(4-hydroxyphenyl)propane, trimethylolpropane triglycidyl ether, and triethylamine is 1.5-2.5:7-9:0.1-0.2; In step A2, the mass ratio of the branched epoxy resin, 3,4-dihydroxybenzoic acid, tetrabutylammonium bromide, tetrahydrofuran, and deionized water is 1:1.2-1.4:0.03-0.05:10-15:8-10; The preparation method of the epoxy-based silane coupling agent modified silica-coated carbon nanotubes includes the following steps: B1. Multi-walled carbon nanotubes are subjected to mixed acid oxidation treatment to obtain pretreated multi-walled carbon nanotubes; B2. Take the pretreated multi-walled carbon nanotubes and deionized water, mix them, disperse them by ultrasonication, add anhydrous ethanol, stir by ultrasonication, adjust the pH to 8-9, add tetraethyl orthosilicate, heat and stir, filter, take the solid phase, wash and dry to obtain silica-coated carbon nanotubes. B3. Take the silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water, mix them, disperse them by ultrasonication, heat and stir, filter them, take the solid phase, wash and dry them to obtain the epoxy silane coupling agent modified silica-coated carbon nanotubes. In step B2, the ratio of the pretreated multi-walled carbon nanotubes, deionized water, anhydrous ethanol, and tetraethyl orthosilicate is 2-3g: 150-250mL: 100-200mL: 4.5-5.5g. In step B3, the ratio of silica-coated carbon nanotubes, anhydrous ethanol, KH560, and deionized water is 1.2-1.6g: 50-80mL: 3-5mL: 40-60mL.

2. The method for preparing a high-temperature resistant PET composite release film according to claim 1, characterized in that, The process parameters for the corona treatment are: operating frequency 15-25kHz, power 8-10kW, processing speed 10-20m / min, and electrode spacing 1-2mm.

3. The method for preparing a high-temperature resistant PET composite release film according to claim 1, characterized in that, The specific parameters for the coating are: coating speed of 10-20 m / min and coating thickness of 5-10 μm.

4. A high-temperature resistant PET composite release film prepared by the preparation method according to any one of claims 1-3.

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