Polyester master batch for high-performance release film and preparation method of polyester master batch

Abstract

The invention discloses a polyester master batch for a high-performance release film and a preparation method of the polyester master batch. The master batch is prepared by carrying out esterification and polycondensation on raw materials including terephthalic acid, ethylene glycol, a micro-nano anti-blocking agent and a stabilizer. The micro-nano anti-blocking agent is prepared by the following method: S1, preparing submicron hollow mesoporous silicon; s2, preparing nano silica sol; s3, preparing a mesoporous silicon supported catalyst; and S4, preparing the micro-nano anti-blocking agent. The polyester master batch for the high-performance release film is synthesized in situ by adding the micro-nano anti-blocking agent, the process is simpler and more convenient than coating, the particle dispersion resistance is smaller than co-extrusion, the dispersity is better, the anti-blocking performance of the film is ensured by adding the submicron particles (submicron hollow meso-porous silicon), and the growth of spherulites can be inhibited by adding the nano particles (nano silica sol), so that the release film is prepared. Generation of small crystals is promoted, and the optical performance of the film can be enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polyester masterbatch materials, in particular to a polyester masterbatch for high-performance release film and a preparation method thereof. BACKGROUND

[0002] PET, full name polyethylene terephthalate, is a thermoplastic polyester with excellent performance, widely used in aerospace, food and medicine, textiles, packaging, electronics, machinery and other fields. In 2024, China's polyester production capacity reached 8000 tons / year. Currently, PET polyester is mostly used in the textile field, and its product added value is relatively low. In recent years, with the increasing market share of electronic and electrical products, there is a large gap in the domestic market for high-end optical films. Therefore, developing polyester masterbatch for high-end optical films can increase the added value of PET products and has broad market development prospects.

[0003] PET release film, also known as release film, isolation film, anti-adhesion film, and separation film, has been widely used in packaging, printing, flexible circuit, insulation products, adhesive products, die cutting and forming processing industries. It is closely related to our lives. Optical release film is mainly used in electronic display and optical instruments. Compared with ordinary release film, optical release film has low haze, high transmittance, and high definition.

[0004] PET release film is composed of polyester film and anti-adhesion isolation layer. The anti-adhesion isolation layer is a release agent coating, which is mainly used for surface treatment of PET substrate, including coating silicon release agent, fluorine release agent or plasma treatment. According to different use scenarios, it has stable release force for different substrates. In addition to the surface release coating, the PET polyester base film must have anti-adhesion properties. Usually, anti-adhesion particles are added during film production to increase the roughness of the film surface, so that the polyester has good smoothness and winding function. In the prior art, anti-adhesion particles are usually directly coated on the base film. Secondly, the anti-adhesion masterbatch is prepared by blending and extruding the chips and particles or synthesized by in-situ polymerization.

[0005] Patent CN 113978086 B adopts an online coating method to obtain an easy-to-peel MLCC release film. The patent uses plasma to treat the surface of the film, making the bonding force between the silicon oil and the film better, and the ceramic peeling performance better. However, the stability of the MLCC release film obtained by coating method is relatively poor, the distribution of the silicon oil is not uniform enough, and the process steps are relatively complicated, with high cost.

[0006] Patent CN 114103360 A uses nano-graphite as an opening agent to prepare a master batch for preparing an MLCC release film base film by melt extrusion. The process flow is simple, but the viscosity of the polyester system is large during co-extrusion, the particles are not easy to flow and migrate and disperse, the uniformity is poor and easy to agglomerate and accumulate into large particles, resulting in a larger surface roughness of the release film.

[0007] Patent CN 113956448 A hydrolyzes under weak alkaline conditions to obtain a larger particle size silica sol, adds the silica sol to the reaction system after esterification is completed, and obtains a master batch after in-situ polymerization. After pelletizing, stretching and then obtaining a film, the anti-blocking property of the film is significantly improved. The sub-micron silica particles synthesized by the patent have low surface activity and are not easy to agglomerate. The uniform distribution of the particles in the master batch is realized by modifying with a coupling agent, and the anti-blocking property of the film is good. However, the larger particle size particles do not improve the crystallization property of the polyester, cannot reduce the spherulite ratio, and reduce the light transmittance of the film, increase the haze, affect the optical performance of the film, and cannot be applied to the optical display field.

[0008] Patent CN 115894982 A prepares a nano-silica sol by particle exchange method, which has small particle size and good dispersibility. The nano-silica sol is added to the reaction system during the esterification stage, and a master batch is obtained after in-situ polymerization. The nano-particles can promote the generation of crystal nuclei and inhibit the growth of spherulites. The prepared film has good light transmittance, low haze and low surface roughness, but the gap between the films is small and easy to block, the anti-blocking property of the film is poor, and the winding and slitting are affected.

[0009] From the above prior art, it can be seen that the in-line coating method and the blending extrusion method have certain limitations, and the separately added nano and micro opening agents in the in-situ polymerization method have advantages and disadvantages. SUMMARY

[0010] The technical problem to be solved by the present application is to provide a high-performance polyester master batch for release film and a preparation method thereof to solve the problems in the prior art. A micro-nano opening agent is first prepared. Nano-particles (nano-silica sol) are used to promote crystallization and inhibit spherulite growth to improve optical performance. Micro-mesoporous particles (sub-micron hollow mesoporous silica) are used to increase the gap between the films and improve the opening performance of the film. Nano-catalysts are loaded in the micro-mesoporous particles in-situ to inhibit the agglomeration of the nano-catalysts, improve the end-capping efficiency of the silica particles, and further reduce the blocking effect of the film. The functional master batch is directly synthesized by in-situ polymerization, and the process is simpler than the coating method, and the particle dispersibility is better than the blending extrusion.

[0011] To achieve the above object, the technical scheme adopted by the present application is: a polyester master batch for high-performance release film, characterized in that it is prepared by esterification and polycondensation process of raw materials including terephthalic acid, ethylene glycol, micro-nano opening agent and stabilizer;

[0012] The micro-nano opening agent is prepared by the following method:

[0013] S1, preparing sub-micron hollow mesoporous silica;

[0014] S2, preparing nano-silica sol;

[0015] S3, loading TiO2 and ZnO on the sub-micron hollow mesoporous silica to prepare a mesoporous silica supported catalyst;

[0016] S4, mixing the nano-silica sol prepared in step S2 with the mesoporous silica supported catalyst prepared in step S3 to prepare a micro-nano opening agent.

[0017] Preferably, the micro-nano opening agent is prepared by the following method:

[0018] S1, preparing sub-micron hollow mesoporous silica:

[0019] Under stirring conditions, deionized water, ethanol, a template agent and ammonia water are mixed uniformly, stirred, and then the ethanol solution of a silicon source is added dropwise, reacted, centrifuged, washed with water and alcohol, added to an acidic ethanol solution, heated to reflux, dried to obtain sub-micron hollow mesoporous silica;

[0020] S2, preparing nano-silica sol:

[0021] Deionized water is added to the ethylene glycol solution of tetraethyl orthosilicate, and then an acidic solution is added dropwise to adjust the pH to 3-4, heated and stirred, a dispersing agent is added, and the stirring is continued, the water in the system is removed by heating, and the nano-silica sol is obtained;

[0022] S3, loading TiO2 and ZnO on the sub-micron hollow mesoporous silica to prepare a mesoporous silica supported catalyst;

[0023] The sub-micron hollow mesoporous silica prepared in step S1 is added to the ethanol solution of Ti source and Zn source, heated and stirred to reflux, reacted, centrifuged, water vapor is introduced in a sealed environment, heated and treated, cooled to room temperature, and finally supercritical dried to obtain the mesoporous silica supported catalyst;

[0024] S4, mixing the nano-silica sol prepared in step S2 with the mesoporous silica supported catalyst prepared in step S3 by ball milling to prepare a micro-nano opening agent.

[0025] Preferably, step S1 is specifically:

[0026] 35-45℃, under stirring, mix deionized water, ethanol, template agent, 20-25% ammonia water by mass fraction, stir for 15-60min, drop in ethanol solution of silicon source, react for 18-30h, centrifuge, wash with water and alcohol, add to acid ethanol solution, reflux at 70-90℃ for 8-12h, dry to obtain sub-micron hollow mesoporous silica.

[0027] Preferably, in step S1:

[0028] The mass ratio of deionized water to ethanol is 9:1-1:9;

[0029] The volume ratio of the sum of deionized water and ethanol to ammonia water is 150:1-50:1;

[0030] In the ethanol solution of silicon source, the mass fraction of silicon source is 10-50%; the added amount of silicon source accounts for 1-20% of the total mass of water and ethanol;

[0031] The silicon source includes silicate and silane coupling agent, and the molar ratio of silicate to silane coupling agent is 9:1-20:1; the silicate is tetraethyl orthosilicate, and the silane coupling agent is at least one of bis(3-triethoxysilylpropyl)amine, bis-(γ-trimethoxysilylpropyl)amine, N-phenylaminomethyl triethoxysilane, and at least one of γ-mercaptopropyl trimethoxysilane and γ-mercaptopropyl triethoxysilane;

[0032] The template agent is a cationic surfactant, and the molar ratio of silicon source to template agent is 10:1-60:1.

[0033] Preferably, the sub-micron hollow mesoporous silica has a particle size of 0.5-1μm and a pore size of 5-15nm.

[0034] Preferably, step S2 is specifically:

[0035] At 30℃, add deionized water to the ethylene glycol solution of tetraethyl orthosilicate, then drop in an acid solution with a concentration of 0.1-0.8mol / L to adjust the pH to 3-4, heat and stir, keep at 50-80℃ for 1.5-6h, then add a dispersant, continue to stir for 1-3h, raise the temperature to 110-130℃ to remove water in the system, and obtain a nanometer silica sol;

[0036] The content of tetraethyl orthosilicate in the ethylene glycol solution of tetraethyl orthosilicate is 10-50wt%, and the molar ratio of tetraethyl orthosilicate to added deionized water is ≥4;

[0037] The acid solution is a deionized water solution of at least one of HCl, HNO3, H2SO4, HClO4, HBr, and HI;

[0038] The dispersant is at least one of polyethylene glycol 200, polyethylene glycol 400, and polyethylene glycol 600.

[0039] Preferably, step S3 is specifically:

[0040] The sub-micron hollow mesoporous silica prepared in step S1 is added into an ethanol solution of Ti source and Zn source, and stirred to be heated to 70-90 DEG C, and refluxed for 2-4 hours, and then centrifuged, dried, and placed in a closed environment to introduce water vapor, and keep the closed environment pressure higher than normal pressure, and heated to 110-130 DEG C for 15-60 minutes, and then cooled to normal temperature for 15-60 minutes, and finally supercritical dried to obtain a mesoporous silica supported catalyst.

[0041] Preferably, in step S3, the Ti source is a titanium acid ester, and is at least one of tetramethyl titanate, tetraethyl titanate, n-butyl titanate, isopropyl titanate, and tetraisopropyl titanate, the Zn source is Zn(OH)2, the molar ratio of the titanium acid ester to Zn(OH)2 is 1:2-1:6, and the mass ratio of the sum of the Ti source and the Zn source to ethanol is 1:20-1:10.

[0042] Preferably, step S4 is specifically:

[0043] The nano-silica sol prepared in step S2 is mixed with the mesoporous silica supported catalyst prepared in step S3, and ball milled at 500-2000 rpm / min for 0.5-2 hours to obtain a micro-nano opening agent.

[0044] Preferably, the molar ratio of terephthalic acid to ethylene glycol is 1.1:1-1.4:1, and the content of the micro-nano opening agent in the raw material is 3000-10000 ppm.

[0045] Preferably, the stabilizer is one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, triphenyl phosphite, phosphorous acid, and polyphosphoric acid, and the addition amount of the stabilizer is controlled according to the P content in the raw material, which is 10-50 ppm.

[0046] The application further provides a preparation method of the polyester master batch for the high-performance release film.

[0047] After terephthalic acid, ethylene glycol, and micro-nano opening agent are stirred uniformly, they are added into a reaction kettle. After air is replaced by nitrogen, the temperature is raised to 220-245 DEG C. Esterification is carried out under the condition that the pressure is 300-350 KPa. The progress of the esterification reaction is measured by the yield of esterification product water. When the esterification rate reaches 94%, the esterification is completed. The stabilizer is added into the kettle. In 1 h, the pressure in the reaction kettle is gradually reduced from normal pressure to 20-50 Pa by using a vacuum pump. The temperature is raised to 270-285 DEG C. Chain growth reaction is carried out. When the product in the kettle reaches the target viscosity, the product is discharged, cooled, and cut into particles to obtain polyester masterbatch for high-performance release film.

[0048] Preferably, the target viscosity is 0.6-0.65 dL / g.

[0049] The beneficial effects of the present application are:

[0050] 1. In the preparation of sub-micron hollow mesoporous silica, the present application introduces macromolecular silane coupling agent with polar groups. One end serves as a silicon source to generate spheres and channels, and the other polar group appears in the channels and surface, which can firmly bond the polar polyester molecular chain, so that the silica spheres are firmly anchored on the surface of the polyester and are not easy to fall off. The long molecular chain is not easy to participate in the chain growth reaction.

[0051] 2. The present application loads catalyst precursors on the surface of sub-micron hollow mesoporous silica and in the channels and generates catalyst in situ, so that the polymerization monomer or small molecular chain can perform chain growth reaction inside the channel, which can reduce the small molecular chain, improve the end-capping efficiency, reduce the exposed molecular chain, and further reduce the film adhesion; in-situ loading can also inhibit the agglomeration of nano-catalysts, so that the molecular chain distribution is widened and the masterbatch performance is improved.

[0052] 3. In the present application, Zn(OH)2 is dehydrated to generate ZnO in a high-temperature sealed environment. Because of the capillary effect of the small pore size, the water removed by Zn(OH)2 is not easy to discharge. After the temperature is reduced, the water vapor is liquefied and reacts with titanate. After the reaction is completed, the channel structure is not easy to be damaged by supercritical drying, and the excess water in the channel and the reaction residues can be removed.

[0053] 4. The present application in-situ synthesizes polyester masterbatch for high-performance release film by adding micro-nano opening agent. The process is simpler than coating, the particle dispersion resistance is smaller than co-extrusion, and the dispersibility is better. The sub-micron particles (sub-micron hollow mesoporous silica) are added to ensure the opening performance of the film. The nano-particles (nano-silica sol) are added to inhibit the growth of spherulites, promote the generation of small crystals, and enhance the optical performance of the film. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is an SEM image of the brittle fracture section of the polyester masterbatch for high-performance release film obtained in Example 2. DETAILED DESCRIPTION

[0055] The application will be further described in conjunction with the following examples, so that those skilled in the art can implement the application according to the description.

[0056] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0057] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are commercially available unless otherwise specified. The specific conditions not specified in the following examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, but are conventional products that can be purchased on the market.

[0058] The application provides a polyester master batch for high-performance release film, which is prepared by esterification and polycondensation process of raw materials including terephthalic acid, ethylene glycol, micro-nano opening agent and stabilizer;

[0059] The micro-nano opening agent is prepared by the following method:

[0060] S1, preparing sub-micron hollow mesoporous silica;

[0061] S2, preparing nano-silica sol;

[0062] S3, loading TiO2 and ZnO on the sub-micron hollow mesoporous silica to prepare a mesoporous silica supported catalyst;

[0063] S4, mixing the nano-silica sol prepared in step S2 with the mesoporous silica supported catalyst prepared in step S3 to prepare a micro-nano opening agent.

[0064] In a preferred embodiment, the micro-nano opening agent is prepared by the following method:

[0065] S1, preparing sub-micron hollow mesoporous silica:

[0066] Under stirring conditions, deionized water, ethanol, a template agent, ammonia water are mixed uniformly, stirred, and the ethanol solution of a silicon source is added dropwise, reacted, centrifuged, washed with water and alcohol, then added to an acidic ethanol solution, heated to reflux, dried to obtain sub-micron hollow mesoporous silica;

[0067] Principle: In this step, a kind of sub-micron hollow mesoporous silica with grafted groups on the surface and in the channel is prepared by template method. When preparing silica, macromolecular silane coupling agent with polar groups is introduced. One end of the macromolecular silane coupling agent is used as a silicon source to generate spheres and channels, and the other end of the macromolecular silane coupling agent is used as a polar group to appear in the channels and on the surface. This can firmly bond the polar polyester molecular chain, so that the silica spheres are firmly anchored on the polyester surface and are not easy to fall off. In addition, the long molecular chain is not easy to participate in chain extension reaction.

[0068] Step S1 can adjust the pore size by adjusting the alcohol-water ratio. A lower alcohol-water ratio can generate a more abundant pore structure.

[0069] S2, preparation of nano-silica sol:

[0070] Deionized water is added to the ethylene glycol solution of tetraethyl orthosilicate, and an acidic solution is added dropwise to adjust the pH to 3-4. Heating and stirring are performed, a dispersing agent is added, and stirring is continued. The system is heated to remove water, and a nano-silica sol is obtained.

[0071] Principle: In this step, the silica obtained by hydrolysis of tetraethyl orthosilicate under acidic conditions is more stable than that under alkaline conditions, and the particle size is more controllable, which can be effectively stored.

[0072] S3, loading TiO2 and ZnO on the sub-micron hollow mesoporous silica to prepare a mesoporous silica supported catalyst;

[0073] The sub-micron hollow mesoporous silica prepared in step S1 is added to an ethanol solution of Ti source and Zn source, and refluxed under heating and stirring. After the reaction is completed, centrifugation is performed, water vapor is introduced in a sealed environment, and the temperature is increased for treatment. After the temperature is reduced to room temperature, it is maintained, and finally supercritical drying is performed to obtain a mesoporous silica supported catalyst.

[0074] Principle: In this step, the catalyst precursor is loaded on the surface of the sub-micron silica spheres and in the channels, and the catalyst is generated in situ. This allows the polymerization monomer or small molecular chain to undergo chain extension reaction in the channel, which can reduce the small molecular chain, improve the end-capping efficiency, reduce the exposed molecular chain, and further reduce the film adhesion. In-situ loading can also inhibit the agglomeration of the nano-catalyst, widen the molecular chain distribution, and improve the masterbatch performance.

[0075] TiO2 is the main catalyst, but its activity is too high to control, and the reaction stability is poor. The polyester masterbatch obtained is prone to yellowing, which affects the color value of the masterbatch. ZnO is used as a co-catalyst to regulate its catalytic activity and perform synergistic catalysis.

[0076] In a high-temperature closed environment, Zn(OH)2 is dehydrated to generate ZnO. Because of the capillary effect caused by the small pore size, the water removed from Zn(OH)2 is not easy to discharge. After re-cooling, the water vapor is liquefied and reacts with titanate. After the reaction is completed, the pore structure is not easily damaged by supercritical drying, and the excess water in the pores and reaction residues are removed.

[0077] S4, mixing the nanometer silicon sol prepared in step S2 and the mesoporous silicon supported catalyst prepared in step S3 by ball milling to prepare a micro-nano opening agent.

[0078] In a preferred embodiment, step S1 is specifically:

[0079] In a preferred embodiment, step S1 is specifically:

[0080] In a preferred embodiment, step S1 is specifically:

[0081] The mass ratio of deionized water to ethanol is 9:1 to 1:9, and more preferably 6:4.

[0082] The volume ratio of the sum of the volumes of deionized water and ethanol to the volume of ammonia is 150:1 to 50:1.

[0083] The mass fraction of the silicon source in the ethanol solution of the silicon source is 10% to 50%; the addition amount of the silicon source accounts for 1% to 20% of the total mass of water and ethanol; and more preferably 30%.

[0084] The silicon source includes silicate and silane coupling agent, and the molar ratio of silicate to silane coupling agent is 9:1 to 20:1; the silicate is tetraethyl orthosilicate, and the silane coupling agent is at least one of bis(3-triethoxysilylpropyl)amine, bis-(γ-trimethoxysilylpropyl)amine, and N-phenylaminomethyltriethoxysilane; and the thiol coupling agent is at least one of γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane.

[0085] The template agent is a cationic surfactant, and the molar ratio of the silicon source to the template agent is 10:1 to 60:1, and more preferably 20:1 to 40:1.

[0086] In a preferred embodiment, the particle size of the sub-micron hollow mesoporous silica is 0.5 to 1 μm, and the pore size is 5 to 15 nm.

[0087] In a preferred embodiment, step S2 is specifically:

[0088] The ethylene glycol solution of tetraethyl orthosilicate is added with deionized water at 30℃, and an acid solution with a concentration of 0.1-0.8 mol / L is added dropwise to adjust the pH to 3-4, heated and stirred, and kept at 50-80℃ for 1.5-6h, then a dispersant is added, and the stirring is continued for 1-3h, and the temperature is increased to 110-130℃ to remove the water in the system, to obtain a nanometer silicon sol.

[0089] In a preferred embodiment, in step S2:

[0090] The content of tetraethyl orthosilicate in the ethylene glycol solution of tetraethyl orthosilicate is 10-50wt%;

[0091] The molar ratio of tetraethyl orthosilicate to the added deionized water is ≥4;

[0092] The acid solution is a deionized water solution of at least one of HCl, HNO3, H2SO4, HClO4, HBr, and HI; more preferably HCl, and the concentration of the acid solution is preferably 0.4 mol / L;

[0093] The dispersant is at least one of polyethylene glycol 200, polyethylene glycol 400, and polyethylene glycol 600. The mass ratio of nanometer silicon to dispersant is 5:1-15:1, and more preferably 10:1.

[0094] In a preferred embodiment, the particle size of the nanometer silicon prepared in step S2 is 20-60nm.

[0095] In a preferred embodiment, the temperature of the heat preservation and stirring in step S2 is 60℃.

[0096] In a preferred embodiment, step S3 is specifically:

[0097] The sub-micron hollow mesoporous silica prepared in step S1 is added into an ethanol solution of a catalyst precursor (a Ti source and a Zn source), and the temperature is increased to 70-90℃ under stirring, and refluxed for 2-4h, centrifuged, dried until the Ti source loading is 40-60wt%, and then placed in a sealed environment to introduce water vapor, keep the sealed environment pressure higher than the normal pressure, increase the temperature to 110-130℃, keep for 15-60min, then decrease the temperature to normal temperature, keep for 15-60min, and finally supercritical drying to obtain a mesoporous silica supported catalyst.

[0098] In a preferred embodiment, in step S3:

[0099] The molar ratio of the sub-micron hollow mesoporous silica to the catalyst precursor is 12:1-20:1;

[0100] The Ti source is a titanate, specifically at least one of tetramethyl titanate, tetraethyl titanate, n-butyl titanate, isopropyl titanate, and tetraisopropyl titanate, the Zn source is Zn(OH)2, the molar ratio of the titanate to Zn(OH)2 is 1:2-1:6, and the mass ratio of the sum of the mass of the Ti source and the Zn source to the mass of ethanol is 1:20-1:10.

[0101] In a preferred embodiment, step S4 specifically comprises:

[0102] The nanosilica sol prepared in step S2 is mixed with the mesoporous silicon supported catalyst prepared in step S3, and ball milling is performed at 500-2000 rpm / min for 0.5-2 h to prepare the micro-nano opening agent.

[0103] In a preferred embodiment, the molar ratio of terephthalic acid to ethylene glycol is 1.1:1-1.4:1, and the content of the micro-nano opening agent in the raw material is 3000-10000 ppm.

[0104] In a preferred embodiment, the stabilizer is one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, triphenyl phosphite, phosphorous acid, and polyphosphoric acid, and the addition amount of the stabilizer is controlled according to the content of P in the raw material, which is 10-50 ppm.

[0105] In a preferred embodiment, the polyterephthalic acid is selected from China Hengli Petrochemical Co., Ltd., and the ethylene glycol is imported from Saudi Arabia.

[0106] The application also provides a preparation method of the polyester master batch for high-performance release film, comprising the following steps:

[0107] After the terephthalic acid, the ethylene glycol, and the micro-nano opening agent are uniformly stirred, they are added into a reaction kettle, air is replaced by nitrogen, the temperature is raised to 220-245℃, and esterification is performed under a pressure of 300-350 KPa, the progress of the esterification reaction is measured by the yield of water produced by the esterification product, the esterification is completed when the esterification rate reaches 94%, the stabilizer is added into the kettle, the pressure in the reaction kettle is gradually reduced from normal pressure to 20-50 Pa by a vacuum pump within 1 h, the temperature is raised to 270-285℃, and polycondensation chain growth reaction is performed, the product in the kettle reaches the target viscosity, the product is discharged, cooled, and pelletized to obtain the polyester master batch for high-performance release film.

[0108] In a preferred embodiment, the target viscosity is 0.6-0.65 dL / g.

[0109] The above is the general idea of the application, and the following provides detailed examples and comparative examples based on the general idea to further illustrate the application.

[0110] Example 1

[0111] S1, Preparation of sub-micron hollow mesoporous silica:

[0112] Mix 530.0 g of deionized water, 434.0 g of ethanol, 0.92 g of cetyltrimethylammonium bromide, and 7 ml of ammonia water uniformly at 40°C under stirring conditions. After stirring for 0.5 h, titrate 9.5 g of tetraethyl orthosilicate, 1.1 g of bis(3-triethoxysilylpropyl)amine, and 96.0 g of ethanol into the mixture. After reaction for 18 h, centrifuge, wash with water and alcohol, and add to an acidic ethanol solution. Reflux at 80°C for 8 h, and dry to obtain sub-micron hollow mesoporous silica spheres.

[0113] S2, Preparation of nano-silica sol:

[0114] Prepare a 936.0 g ethylene glycol solution of tetraethyl orthosilicate with a mass fraction of 10%. At 30°C, first add 32.4 g of deionized water, and then add a 0.1 mol / L HCl solution dropwise until the solution pH = 3. After 3 h of incubation and stirring at 50°C, add 5.4 g of polyethylene glycol 200, and continue stirring for 1 h. Increase the temperature to 120°C to remove water from the system, and obtain nano-silica sol.

[0115] S3, Preparation of mesoporous silica supported catalyst:

[0116] Take 3.0 g of the sub-micron hollow mesoporous silica spheres prepared in step 1, and immerse them in a mixed solution of 0.90 g of tetraethyl titanate, 1.23 g of Zn(OH)2, and 25.0 g of ethanol. Under gentle stirring, increase the temperature to 80°C, and reflux for 2 h. After centrifugation and drying, the theoretical amount of tetraethyl titanate loading is 50% (gravimetric method). Place the sample in a closed environment, and introduce water vapor while maintaining the closed environment pressure slightly higher than normal pressure. Increase the temperature to 120°C for about 0.5 h, and then decrease the temperature to room temperature for 0.5 h. Perform supercritical drying to obtain a mesoporous silica supported catalyst.

[0117] S4, Preparation of micro-nano opening agent:

[0118] Add the mesoporous silica supported catalyst obtained in step S3 to the nano-silica sol obtained in step S2, and perform ball milling at 1000 rpm / min for 1 h to obtain a micro-nano opening agent.

[0119] S5, Synthesis of polyester pellets for high-performance release film:

[0120] 8.6 kg of terephthalic acid, 2.65 kg of ethylene glycol, and 945.0 g of a micro-nano opening agent were stirred uniformly and then added to a 20 L batch reactor. After replacing the air with nitrogen, the temperature was raised to 240°C, and esterification was carried out at a pressure of 325 KPa. The progress of the esterification reaction was measured by the amount of water produced by the esterification product. When the esterification rate reached 94%, the esterification was completed. Then, 0.26 g of trimethyl phosphate was added to the reactor. The pressure in the reactor was gradually reduced from atmospheric pressure to 35 Pa within 1 h using a vacuum pump. The temperature was raised to 280°C, and the polycondensation chain growth reaction was carried out. When the product in the reactor reached 0.6 dL / g, the product was discharged, cooled, and pelletized to obtain polyester pellets for high-performance release films.

[0121] Example 2

[0122] S1, Preparation of sub-micron hollow mesoporous silica:

[0123] At 40°C, 203.1 g of deionized water, 182.0 g of ethanol, 1.21 g of cetyltrimethylammonium bromide, and 4.7 ml of ammonia water were stirred uniformly. After stirring for 0.5 h, 19 g of tetraethyl orthosilicate, 2.38 g of γ-mercaptopropyltriethoxysilane, and 50.0 g of ethanol were added dropwise. After reacting at 100°C for 24 h, the mixture was centrifuged, washed with water and alcohol, and then added to an acidic ethanol solution. After refluxing at 80°C for 10 h, the sub-micron hollow mesoporous silica spheres were obtained after drying.

[0124] S2, Preparation of nano-silica sol:

[0125] A 624.0 g ethylene glycol solution of tetraethyl orthosilicate with a mass fraction of 30% was prepared. At 30°C, 85.5 g of deionized water was first added, and then a 0.4 mol / L HCl solution was added dropwise until the pH of the solution was 3-4. After stirring at 65°C for 3 h, 18.7 g of polyethylene glycol 400 was added and stirring was continued for 1 h. The temperature was then raised to 120°C to remove water from the system, and the nano-silica sol was obtained.

[0126] S3, Preparation of mesoporous silica supported catalyst:

[0127] 6.0 g of the sub-micron hollow mesoporous silica spheres prepared in step 1 were immersed in a mixed solution of 1.06 g of n-butyl titanate, 1.32 g of Zn(OH)2, and 35.7 g of ethanol. The temperature was raised to 80°C under gentle stirring, and refluxing was carried out for 2 h. After centrifugation and drying, the theoretical amount of tetraethyl orthotitanate loading was 50% (determined by weighing). The system was then placed in a closed environment, water vapor was introduced, and the pressure in the closed environment was maintained slightly higher than atmospheric pressure. The temperature was raised to 120°C for about 0.5 h, and then the temperature was reduced to room temperature and maintained for 0.5 h. Finally, supercritical drying was carried out to obtain the silica-based titanium catalyst.

[0128] S4, Preparation of micro-nano opening agent:

[0129] The mesoporous silica supported catalyst obtained in step S3 was added to the nanosilica sol prepared in step 2, and after ball milling at 1000 rpm / min for 1 h, a micro-nano opening agent was obtained.

[0130] S5, synthesis of polyester pellets for high-performance release film:

[0131] After 8.6 kg of terephthalic acid, 3.44 kg of ethylene glycol, and 650.0 g of micro-nano opening agent dispersion were stirred uniformly, they were added to a 20 L batch reactor. After replacing the air with nitrogen, the temperature was raised to 240°C, and the esterification reaction was carried out at a pressure of 325 KPa. The progress of the esterification reaction was measured by the amount of water produced by the esterification product. When the esterification rate reached 94%, the esterification was complete. 2.0 g of triphenyl phosphite was added to the reactor, and the pressure in the reactor was gradually reduced from atmospheric pressure to 35 Pa using a vacuum pump within 1 h. The temperature was raised to 280°C, and the polycondensation chain growth reaction was carried out. When the product in the reactor reached a certain viscosity, it was discharged, cooled, and pelletized to obtain polyester pellets for high-performance release film.

[0132] Reference Figure 1 Figure 2 is a SEM image of the brittle fracture section of the polyester pellets for high-performance release film obtained in Example 2.

[0133] Example 3

[0134] S1, preparation of sub-micron hollow mesoporous silica:

[0135] Under stirring at 40°C, 153.5 g of deionized water, 73.5 g of ethanol, 1.52 g of cetyltrimethylammonium bromide, and 6.13 ml of ammonia water were mixed uniformly. After stirring for 0.5 h, 31.2 g of tetraethyl orthosilicate, 2.9 g of bis-(γ-trimethoxysilylpropyl) amine, and 80.0 g of ethanol were added dropwise. After reaction at 80°C for 30 h, centrifugation, water washing, and alcohol washing, the product was added to an acidic ethanol solution, refluxed at 80°C for 12 h, and dried to obtain sub-micron hollow mesoporous silica spheres.

[0136] S2, preparation of nanosilica sol:

[0137] A 624.0 g ethylene glycol solution of tetraethyl orthosilicate with a mass fraction of 50% was prepared. At 30°C, 162.0 g of deionized water was first added, and then a 0.8 mol / L HCl solution was added dropwise until the solution pH was 3-4. After stirring at 50°C for 3 h, 31.2 g of polyethylene glycol 600 was added, and stirring was continued for 1 h. The temperature was raised to 120°C to remove water from the system, and a nanosilica sol was obtained.

[0138] S3, preparation of mesoporous silica supported catalyst:

[0139] Take 9.0 g of sub-micron hollow mesoporous silica balls prepared in step 1 and immerse them in a mixed solution of 2.37 g of titanium isopropylate, 3.72 g of Zn(OH)2, and 61.0 g of ethanol. Under gentle stirring, heat to 80°C and reflux for 2 h. After centrifugation, dry to a theoretical amount of 50% of titanium tetraisopropoxide loading (gravimetric method), and place in a closed environment. Introduce water vapor, maintain the closed environment pressure slightly higher than normal pressure, heat to 120°C for about 0.5 h, and then cool to room temperature for 0.5 h. Then perform supercritical drying to obtain a mesoporous silica supported catalyst.

[0140] S4, Preparation of micro-nano opening agent:

[0141] Add the mesoporous silica supported catalyst obtained in step S3 to the nanosilica sol obtained in step S2. After ball milling at 1000 rpm / min for 1 h, a micro-nano opening agent is obtained.

[0142] S5, Synthesis of polyester pellets for high-performance release film:

[0143] After stirring 8.6 kg of terephthalic acid, 4.17 kg of ethylene glycol, and 660.6 g of micro-nano opening agent dispersion liquid uniformly, add them to a 20 L batch reactor. Replace the air with nitrogen, heat to 240°C, and perform esterification under a pressure of 325 KPa. Measure the progress of the esterification reaction by the amount of water produced by the esterification product. When the esterification rate reaches 94%, the esterification is complete. Add 3.0 g of triphenyl phosphate to the reactor, gradually reduce the pressure in the reactor to 35 Pa using a vacuum pump within 1 h, and heat to 280°C to perform polycondensation chain growth reaction. When the product in the reactor reaches 0.65 dL / g, discharge, cool, and pelletize to obtain polyester pellets for high-performance release film.

[0144] Comparative Example 1

[0145] S1, Preparation of sub-micron hollow mesoporous silica:

[0146] Under stirring at 40°C, mix 203.1 g of deionized water, 182.0 g of ethanol, 1.21 g of cetyltrimethylammonium bromide, and 4.7 ml of ammonia water uniformly. After stirring for 0.5 h, titrate a mixed solution of 19 g of tetraethyl orthosilicate, 2.38 g of γ-mercaptopropyl triethoxysilane, and 50.0 g of ethanol. React at 100°C for 24 h, centrifuge, wash with water and alcohol, add to an acidic ethanol solution, reflux at 80°C for 10 h, and dry to obtain sub-micron hollow mesoporous silica balls.

[0147] S2, Preparation of mesoporous silica supported catalyst:

[0148] Take 6.0 g of sub-micron hollow mesoporous silica spheres prepared in step 1 to soak in a mixed solution of 1.06 g of n-butyl titanate, 1.32 g of Zn(OH)2 and 35.7 g of ethanol, and heat to 80°C under gentle stirring, reflux for 2 h, then centrifuge and dry until the theoretical amount of tetramethyl titanate loading reaches 50% (gravimetric method), place in a closed environment, introduce water vapor, maintain the closed environment pressure slightly higher than normal pressure, heat to 120°C for about 0.5 h, then cool to room temperature for 0.5 h, and then perform supercritical drying to obtain a mesoporous silica supported catalyst.

[0149] S3, synthesis of polyester pellets for high-performance release film:

[0150] After stirring 8.6 kg of terephthalic acid, 3.82 kg of ethylene glycol and 9.2 g of mesoporous silica supported catalyst, add them to a 20 L batch reactor, replace the air with nitrogen, heat to 240°C, and perform esterification under a pressure of 325 KPa. The progress of the esterification reaction is measured by the amount of water produced by the esterification product. When the esterification rate reaches 94%, the esterification is complete. Add 2.0 g of triphenyl phosphite to the reactor, gradually reduce the pressure in the reactor from normal pressure to 35 Pa with a vacuum pump within 1 h, and heat to 280°C to perform the polycondensation chain growth reaction. When the product in the reactor reaches a certain viscosity, discharge, cool and pelletize to obtain polyester pellets for high-performance release film.

[0151] Comparative Example 2

[0152] S1, preparation of nano-silica sol:

[0153] Prepare a 624.0 g ethylene glycol solution of tetraethyl orthosilicate with a mass fraction of 30%. At 30°C, first add 85.5 g of deionized water, then add a 0.4 mol / L HCl solution dropwise until the solution pH is 3-4. After stirring at 65°C for 3 h, add 18.7 g of polyethylene glycol 400 and continue stirring for 1 h. Heat to 120°C to remove water from the system to obtain a nano-silica sol.

[0154] S2, synthesis of polyester pellets for high-performance release film:

[0155] 8.6 kg of terephthalic acid, 3.44 kg of ethylene glycol, 624.0 g of nano-silica sol, 35 ppm of n-butyl titanate and 24 ppm of zinc oxide were stirred uniformly and then added into a 20 L batch reactor. After replacing the air with nitrogen, the temperature was raised to 240°C, and the esterification reaction was carried out at a pressure of 325 KPa. The progress of the esterification reaction was measured by the yield of water produced by the esterification product. When the esterification rate reached 94%, the esterification was completed. 2.0 g of triphenyl phosphite was added into the reactor, and the pressure in the reactor was gradually reduced from normal pressure to 35 Pa within 1 h by using a vacuum pump. The temperature was raised to 280°C, and the polycondensation chain growth reaction was carried out. When the product in the reactor reached a certain viscosity, it was discharged, cooled and cut into granules to obtain polyester granules for high-performance release film.

[0156] Comparative Example 3

[0157] S1, Preparation of sub-micron hollow mesoporous silica:

[0158] 203.1 g of deionized water, 182.0 g of ethanol, 1.21 g of cetyltrimethylammonium bromide and 4.7 ml of ammonia water were mixed uniformly at 40°C under stirring. After stirring for 0.5 h, 19 g of tetraethyl orthosilicate, 2.38 g of γ-mercaptopropyl triethoxysilane and 50.0 g of ethanol were added dropwise. After reaction at 100°C for 24 h, centrifugation, water washing and alcohol washing, the product was added into an acidic ethanol solution, refluxed at 80°C for 10 h, and dried to obtain sub-micron hollow mesoporous silica spheres.

[0159] S12, Preparation of nano-silica sol

[0160] A 30% mass fraction ethylene glycol solution of tetraethyl orthosilicate was prepared. At 30°C, 85.5 g of deionized water was added, and then a 0.4 mol / L HCl solution was added dropwise until the pH of the solution was 3-4. After stirring at 65°C for 3 h, 18.7 g of polyethylene glycol 400 was added, and the stirring was continued for 1 h. The temperature was raised to 120°C to remove water from the system, and nano-silica sol was obtained.

[0161] S3, Synthesis of polyester granules for high-performance release film:

[0162] 8.6 kg of terephthalic acid, 3.44 kg of ethylene glycol, 642.7 g of nano-silica sol, 6.0 g of sub-micron hollow mesoporous silica, 35 ppm of n-butyl titanate and 24 ppm of zinc oxide were stirred uniformly and then added to a 20 L batch reactor. After replacing the air with nitrogen, the temperature was raised to 240°C, and the esterification reaction was carried out at a pressure of 325 KPa. The progress of the esterification reaction was measured by the amount of water produced by the esterification product. When the esterification rate reached 94%, the esterification was completed. 2.0 g of triphenyl phosphite was added to the reactor, and the pressure in the reactor was gradually reduced from atmospheric pressure to 35 Pa within 1 h. The temperature was raised to 280°C, and the polycondensation chain growth reaction was carried out. When the product in the reactor reached a certain viscosity, it was discharged, cooled, and pelletized to obtain polyester masterbatch for high-performance release film.

[0163] Performance test

[0164] The performance parameters of the polyester masterbatch for high-performance release film obtained in Examples 1-3 and the PET masterbatch obtained in Comparative Examples 1-3 were tested according to the national standard "GB / T 14190-2017", and the results are shown in Table 1.

[0165] The polyester masterbatch for high-performance release film obtained in Examples 1-3 and the PET masterbatch obtained in Comparative Examples 1-3 were respectively pelletized, then cast, multi-layer co-extruded, and double-drawn to obtain a film, which was tested according to the standards "ASTM D1003", "ISO 4287", and "ASTM D882", and the data are shown in Table 2.

[0166] Table 1 Performance parameters of polyester masterbatch for high-performance release film

[0167]

[0168] Table 2 Performance parameters of MLCC release film prepared from polyester masterbatch

[0169]

[0170] As can be seen from Tables 1 and 2, compared with Example 2:

[0171] Comparative Example 1 did not add nano-silica sol compared with Example 2, and the crystallization performance of the obtained masterbatch was worse than that of Example 2, the spherulites were larger, the haze of the obtained film was high, and the tensile strength and elongation at break were low.

[0172] Comparative Example 2 did not add sub-micron hollow mesoporous silica balls compared with Example 2, and the catalyst was not loaded on the sub-micron hollow mesoporous silica balls, and the opening performance of the obtained film was poor.

[0173] Comparative Example 3 does not load catalyst on the surface of the sub-micron hollow mesoporous silica spheres compared to Example 2, the catalyst is more serious agglomeration, the content of the master batch small molecule is higher, the prepared film is easy to break, and the tensile strength is poor.

[0174] In summary, the polyester master batch synthesized in Examples 1-3 of the present application has excellent performance, strong crystallization performance, and the optical performance of the film obtained by double stretching is better, and the opening performance is excellent.

[0175] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily made by those skilled in the art, and therefore the present application is not limited to specific details without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A high-performance polyester masterbatch for release film, characterized in that: It is prepared by esterification and polycondensation of raw materials including terephthalic acid, ethylene glycol, micro-nano opening agent and stabilizer; Wherein, the micro-nano opening agent is prepared by the following method: S1. Preparation of submicron hollow mesoporous silicon; S2, preparing nano-silica sol; S3, loading TiO2 and ZnO on submicron hollow mesoporous silicon to prepare a mesoporous silicon-supported catalyst; S4. Mixing the nano-silica sol prepared in step S2 with the mesoporous silica-supported catalyst prepared in step S3 to prepare a micro-nano opening agent.

2. The high-performance polyester masterbatch for release film according to claim 1, characterized in that: The micro-nano opening agent is prepared by the following method: S1. Preparation of submicron hollow mesoporous silicon: Under stirring conditions, deionized water, ethanol, template agent, and ammonia water are mixed uniformly, stirred, and an ethanol solution of a silicon source is added dropwise, reacted, centrifuged, washed with water and alcohol, added to an acidic ethanol solution, heated under reflux, and dried to obtain submicron hollow mesoporous silicon; S2. Preparation of nano-silica sol: Deionized water is added to the ethylene glycol solution of ethyl orthosilicate, and then an acidic solution is added dropwise to adjust the pH to 3-4. The solution is heated and stirred, and a dispersant is added. The solution is stirred continuously and heated to remove water from the system to obtain a nano-silica sol. S3, loading TiO2 and ZnO on submicron hollow mesoporous silicon to prepare a mesoporous silicon-supported catalyst; The submicron hollow mesoporous silicon prepared in step S1 is added to an ethanol solution of a Ti source and a Zn source, and refluxed under heating and stirring. After the reaction is completed, centrifugation is performed, water vapor is introduced into a closed environment, the temperature is increased, the temperature is lowered to room temperature, and the temperature is maintained, and finally supercritical drying is performed to obtain a mesoporous silicon supported catalyst; S4. Mix the nano-silica sol prepared in step S2 and the mesoporous silica-supported catalyst prepared in step S3 and perform ball milling to prepare a micro-nano opening agent.

3. The high-performance polyester masterbatch for release film according to claim 2, characterized in that: Step S1 is specifically as follows: At 35-45°C, under stirring conditions, deionized water, ethanol, a template, and 20-25% ammonia water are mixed uniformly, stirred for 15-60 minutes, and an ethanol solution of a silicon source is added dropwise. The mixture is reacted for 18-30 hours, centrifuged, washed with water and alcohol, and then added to an acidic ethanol solution. The mixture is refluxed at 70-90°C for 8-12 hours and dried to obtain submicron hollow mesoporous silicon.

4. The high-performance polyester masterbatch for release film according to claim 2, characterized in that: In step S1: The mass ratio of deionized water to ethanol is 9:1 to 1:9; the volume ratio of the sum of the volumes of deionized water and ethanol to ammonia water is 150:1 to 50:1; The silicon source ethanol solution has a mass fraction of 10 to 50% of the silicon source; the amount of the silicon source added accounts for 1 to 20% of the total mass of water and ethanol; the silicon source includes a silicate and a silane coupling agent, and the molar ratio of the silicate to the silane coupling agent is 9:1 to 20:1; the silicate is ethyl orthosilicate; the silane coupling agent is at least one of bis(3-triethoxysilylpropyl)amine, bis-(γ-trimethoxysilylpropyl)amine, and N-phenylaminomethyltriethoxysilane; and the mercapto coupling agent is at least one of γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane. The template agent is a cationic surfactant, and the molar ratio of the silicon source to the template agent is 10:1 to 60:

1.

5. The high-performance polyester masterbatch for release film according to claim 2, characterized in that: Step S2 is specifically as follows: At 30°C, deionized water is added to the ethylene glycol solution of ethyl orthosilicate, and then an acidic solution with a concentration of 0.1-0.8 mol / L is added dropwise to adjust the pH to 3-4. The mixture is heated and stirred, and the mixture is kept stirred at 50-80°C for 1.5-6 hours. After that, a dispersant is added, and the mixture is stirred for 1-3 hours. The mixture is heated to 110-130°C, and the water in the system is removed to obtain a nano-silica sol. The ethylene glycol solution of ethyl orthosilicate contains 10 to 50 wt% ethyl orthosilicate, and the molar ratio of ethyl orthosilicate to the added deionized water is ≥4; The acidic solution is a deionized aqueous solution of at least one of HCl, HNO3, H2SO4, HClO4, HBr, and HI; The dispersant is at least one of polyethylene glycol 200, polyethylene glycol 400, and polyethylene glycol 600.

6. The high-performance polyester masterbatch for release film according to claim 1, characterized in that: Step S3 is specifically as follows: The submicron hollow mesoporous silicon prepared in step S1 is added to an ethanol solution of a Ti source and a Zn source, heated to 70-90° C. with stirring, refluxed for 2-4 hours, centrifuged, and dried until the Ti source loading is 40-60 wt%, then placed in a closed environment and introduced with water vapor, maintaining the closed environment pressure higher than normal pressure, heated to 110-130° C., maintained for 15-60 minutes, then cooled to room temperature, maintained for 15-60 minutes, and finally supercritically dried to obtain a mesoporous silicon-supported catalyst.

7. The high-performance polyester masterbatch for release film according to claim 1, characterized in that: In step S3, the Ti source is titanate, specifically at least one selected from tetramethyl titanate, tetraethyl titanate, n-butyl titanate, isopropyl titanate, and tetraisopropyl titanate; the Zn source is Zn(OH)2; the molar ratio of titanate to Zn(OH)2 is 1:2 to 1:6; and the mass ratio of the sum of the masses of the Ti source and the Zn source to ethanol is 1:20 to 1:

10.

8. The high-performance polyester masterbatch for release film according to claim 1, characterized in that: The molar ratio of terephthalic acid to ethylene glycol is 1.1:1 to 1.4:1, and the content of the micro-nano opening agent in the raw material is 3000 to 10000 ppm.

9. The high-performance polyester masterbatch for release film according to claim 1, characterized in that: The stabilizer is one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, triphenyl phosphite, phosphorous acid, and polyphosphoric acid. The amount of the stabilizer added is controlled according to the P content in the raw material being 10 to 50 ppm.

10. A method for preparing a polyester masterbatch for a high-performance release film, characterized in that: The following steps are involved: After uniformly stirring terephthalic acid, ethylene glycol and micro-nano opening agent, the mixture is added to a reactor. After replacing the air with nitrogen, the temperature is raised to 220-245°C and an esterification reaction is carried out at a pressure of 300-350KPa. The progress of the esterification reaction is measured by the yield of esterification product water. When the esterification rate reaches 94%, the esterification is completed. A stabilizer is added to the reactor. Within 1 hour, the pressure in the reactor is gradually pumped from normal pressure to 20-50Pa using a vacuum pump. The temperature is raised to 270-285°C and a condensation chain growth reaction is carried out. When the product in the reactor reaches the target viscosity, the material is discharged, cooled and pelletized to obtain a polyester masterbatch for a high-performance release film.

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