High-toughness PET film and preparation method thereof

Abstract

The invention discloses a high-toughness PET film and a preparation method thereof, and relates to the technical field of polyester films, the high-toughness PET film comprises the following raw materials by weight: 90-95 parts of PET resin, 5-10 parts of a tackifier, 1-2 parts of a flame retardant, 1-1.5 parts of a plasticizer, 1.5-2 parts of a flexibilizer, 0.6-0.8 part of a lubricant, and 0.2-0.4 part of a nucleating agent. The flexibilizer endows the PET film with relatively strong aging resistance, and the compatibility with PET resin and the tackifier is improved, so that the PET film has high toughness.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polyester films, in particular to a high-toughness PET film and a preparation method thereof. BACKGROUND

[0002] The PET film belongs to polyester films, is usually prepared by using an extrusion method after polyethylene terephthalate is used as a main raw material and is mixed with plasticizers, antioxidants, tackifiers and other additives, and is stretched into a film material after being made into a thick sheet. The PET film has excellent properties such as high strength, good temperature resistance, high barrier property, chemical resistance and easy processing, and is widely applied in the fields of packaging, insulation and optoelectronics.

[0003] The ester bond and benzene ring in the molecular chain of polyethylene terephthalate are easily attacked by ultraviolet light, resulting in the breaking of the ester bond and the generation of free radicals to initiate a chain reaction, thereby causing the material to yellow and the mechanical properties to decrease. Commonly used benzotriazole and thiofene ultraviolet absorbers have strong ultraviolet absorption functions, but they are easy to decompose or migrate at the processing temperature of the PET film, thereby limiting the improvement of the ultraviolet aging resistance of the PET film. EVA (ethylene-vinyl acetate copolymer) can be used to improve the toughness of the PET film, but the compatibility of EVA with polyethylene terephthalate is poor, thereby limiting the use of EVA in the PET film.

[0004] Therefore, it is urgent to develop a suitable modification method and a functional additive with ultraviolet aging resistance suitable for the processing of the PET film, so as to avoid the adverse effects of ultraviolet oxidation on the performance of the PET film and improve the compatibility of EVA with polyethylene terephthalate, so as to obtain a PET film with strong ultraviolet aging resistance and high toughness. SUMMARY

[0005] In order to solve the above technical problems, the application provides a high-toughness PET film and a preparation method thereof.

[0006] The object of the application can be achieved by the following technical scheme.

[0007] The high-toughness PET film comprises the following raw materials in parts by weight: 90-95 parts of PET resin, 5-10 parts of a tackifier, 1-2 parts of a flame retardant, 1-1.5 parts of a plasticizer, 1.5-2 parts of a toughening agent, 0.6-0.8 parts of a lubricant and 0.2-0.4 parts of a nucleating agent.

[0008] The toughening agent is prepared by the following steps.

[0009] Step A1: cyan-containing carbazole, epichlorohydrin, tetramethylammonium bromide, toluene were mixed, and the mixture was reacted at elevated temperature, and then cooled to add potassium carbonate solution, and then stirred to obtain product p1; aromatic formaldehyde, propionic anhydride, and anhydrous sodium carbonate were mixed, and the mixture was stirred at elevated temperature and reflux to obtain product p2;

[0010] Step A2: product p2, toluene were mixed, and then 4-methylpyridine and product p1 were added at elevated temperature, and then stirred to react, and then stirred at elevated temperature to obtain product p3;

[0011] Step A3: 3,4,5-trimethoxybenzoic acid was added to toluene and stirred, and then protective gas was introduced, and then oxalyl chloride and DMF were added under ice water bath, and then the mixture was stirred at room temperature to obtain product p4; product p3, 4-dimethylaminopyridine, potassium carbonate, and DMSO were mixed, and then a solution of product p4 was added under ice water bath, and then the mixture was stirred at elevated temperature to obtain product p5;

[0012] Step A4: product p5, dioxane, and ethyl acetate were mixed, and then palladium-carbon was added and hydrogen was introduced, and then ammonia water was added after the mixture was heated to obtain product p6; product p6, methacrylate, and tetrahydrofuran were mixed and stirred at elevated temperature, and then the mixture was reacted at constant temperature to obtain product p7;

[0013] Step A5: product p7, glacial acetic acid, and aqueous hydrogen bromide were mixed, and then the mixture was heated to reflux and stirred, and then the pH was adjusted to obtain product p8; EVA, product p8, styrene, and initiator were mixed and melt-extruded to obtain a toughening agent.

[0014] Further, the tackifier is EVA-g-MAH.

[0015] Further, the flame retardant is flame retardant DOPO-ITA.

[0016] Further, the plasticizer is diisooctyl phthalate and dioctyl phthalate mixed in a mass ratio of 2-2.5:1-1.5.

[0017] Further, the lubricant is ethylene bisoleic acid amide and paraffin mixed in a mass ratio of 1-1.5:1.5-2.

[0018] Further, the nucleating agent is talc.

[0019] Further, the preparation of the toughening agent comprises the following specific steps:

[0020] Step A1: cyanophenylcarbazole, epichlorohydrin, tetramethylammonium bromide, toluene were mixed and stirred for 25-35 min, and stirred at 80-90℃ for 3.5-4.5 h. After cooling to room temperature, potassium carbonate solution was added, and stirred for 5.5-6.5 h to obtain product p1; aromatic aldehyde, propionic anhydride, anhydrous sodium carbonate were mixed and stirred for 15-20 min, and heated to 100-110℃, and stirred for 2-2.5 h to obtain product p2;

[0021] Further, the amount ratio of cyanophenylcarbazole, epichlorohydrin, tetramethylammonium bromide, toluene, potassium carbonate solution was 21-23 g: 14-16 g: 3.1-3.5 g: 80-90 mL: 18-22 mL; cyanophenylcarbazole was 9H-carbazole-3-cyanide; the mass fraction of potassium carbonate solution was 35-45%; the amount ratio of aromatic aldehyde, propionic anhydride, anhydrous sodium carbonate was 18-20 g: 14-16 g: 2-3 g; aromatic aldehyde was thieno[2,3-C]pyridine-3-formaldehyde;

[0022] In the reaction process of step A1, the secondary amino group of cyanophenylcarbazole was first opened and then closed to react with epichlorohydrin to obtain product p1 containing epoxy group; aromatic aldehyde reacted with propionic anhydride to obtain unsaturated carboxylic acid, i.e. product p2;

[0023] Step A2: product p2, toluene were mixed and stirred for 5-10 min, heated to 50-55℃, 4-methylpyridine, product p1 were added, and stirred for 7.5-8.5 h, and then heated to 100-110℃, and stirred for 2-2.5 h to obtain product p3;

[0024] Further, the amount ratio of product p2, toluene, 4-methylpyridine, product p1 was 25-27 g: 120-130 mL: 2-2.5 g: 32-34 g;

[0025] In the reaction process of step A2, the carboxyl group of product p2 was opened to react with the epoxy group of product p1 to obtain product p3 containing hydroxyl group;

[0026] Step A3: 3,4,5-trimethoxybenzeneacetic acid was added to toluene and stirred for 10-15 min, and protective gas was introduced, and oxalyl chloride and DMF were added under ice water bath, and heated to room temperature, and stirred for 1.5-2 h to obtain product p4; product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO were mixed and stirred for 20-25 min, and the solution of product p4 was added under ice water bath, and then heated to 45-50℃, and stirred for 8.5-9 h to obtain product p5;

[0027] Further, the amount ratio of 3,4,5-trimethoxybenzoic acid, toluene, oxalyl chloride, DMF is 24-26 g:90-100 mL:20-22 g:0.9-1.1 g; the amount ratio of product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO, product p4 solution is 58-60 g:2.5-3 g:14.5-15.5 g:135-145 mL:90-95 mL; the product p4 solution is obtained by stirring and mixing 28-30 g of product p4 and 60-70 mL of DMSO;

[0028] In the reaction process of step A3, the carboxyl group of 3,4,5-trimethoxybenzoic acid reacts with oxalyl chloride to form acyl chloride, and product p4 is obtained; the acyl chloride of product p4 reacts with the hydroxyl group of product p3 to obtain product p5 containing cyano and phenolic ether;

[0029] Step A4: product p5, dioxane, ethyl acetate are mixed and stirred for 30-35 min, palladium-carbon is added and hydrogen is introduced, the temperature is raised to 70-80℃, ammonia water is added, and stirring is carried out for 5-5.5 h to obtain product p6; product p6, methacrylate, tetrahydrofuran are mixed and stirred, and the temperature is raised to 55-65℃, and constant temperature reaction is carried out for 24-25 h to obtain product p7;

[0030] Further, the amount ratio of product p5, dioxane, ethyl acetate, palladium-carbon, ammonia water is 88-90 g:90-100 mL:80-90 mL:1.5-2 g:10-15 mL; the pressure of hydrogen is controlled at 2-3 MPa; the amount ratio of product p6, methacrylate, tetrahydrofuran is 85-87 g:15-17 g:180-190 mL; the methacrylate is glycidyl methacrylate;

[0031] In the reaction process of step A4, the cyano group in product p5 is reduced to primary amino group to obtain product p6; the primary amino group of product p6 opens the ring with the epoxy group in methacrylate to obtain product p7 containing alcohol hydroxyl group;

[0032] Step A5: product p7, glacial acetic acid, aqueous hydrogen bromide solution are mixed, refluxed and stirred at 100-110℃ for 11-12 h, the pH is adjusted to 7.8-8.2 to obtain product p8; EVA, product p8, styrene and initiator are placed in a single screw extruder, and melt extruded at 150-160℃, 90-100 r / min, and then vacuum dried at 50-60℃ to obtain a toughening agent;

[0033] Further, the ratio of the use amount of product p7, glacial acetic acid and aqueous hydrogen bromide solution is 9.2-9.4g:360-370mL:340-350mL; the mass fraction of the aqueous hydrogen bromide solution is 45-55%; the ratio of the use amount of EVA, product p8, 4-methylstyrene and initiator is 100-104g:5-6g:4.5-5g:0.25-0.35g; the initiator is potassium persulfate;

[0034] In the reaction process of step A5, the phenolic ether in product p7 is subjected to demethylation to obtain product p8 containing polyphenol hydroxyl groups; product p8, 4-methylstyrene and EVA are grafted to obtain a toughening agent.

[0035] In another aspect, the application provides a preparation method of the high-toughness PET film, comprising the following steps:

[0036] The PET resin, the adhesion promoter, the flame retardant, the plasticizer, the toughening agent, the lubricant and the nucleating agent are mixed and granulated to obtain granules; the granules are dried, then transferred to a twin-screw extruder for melt extrusion, then cast into a sheet, then stretched, and finally heat set to obtain the high-toughness PET film.

[0037] Further, the preparation of the high-toughness PET film comprises the following specific steps:

[0038] The PET resin, the adhesion promoter, the flame retardant, the plasticizer, the toughening agent, the lubricant and the nucleating agent are mixed and stirred for 1-1.5h, and granulated at 80-90℃ to obtain granules; the granules are dried at 155-165℃ for 4-4.5h, then transferred to a twin-screw extruder for melt extrusion at 285-295℃, then cast into a sheet at 28-32℃, then stretched, and finally heat set at 230-240℃ for 15-25s to obtain the high-toughness PET film.

[0039] Further, the stretching process comprises longitudinal stretching and transverse stretching; the conditions of the longitudinal stretching are a temperature of 115-125℃ and a stretching ratio of 3-4; the conditions of the transverse stretching are a temperature of 120-130℃ and a stretching ratio of 4-5.

[0040] The application has the following beneficial effects:

[0041] The application discloses a high-toughness PET film and a preparation method thereof; the high-toughness PET film is prepared from PET resin, an adhesion promoter, a flame retardant, a plasticizer, a toughening agent and the like.

[0042] The toughening agent is obtained by grafting the product obtained by the reaction of 9H-carbazole-3-cyano, thieno[2,3-C]pyridine-3-formaldehyde, 3,4,5-trimethoxybenzene acetic acid and glycidyl methacrylate, etc. with EVA. The combination of 9H-carbazole-3-cyano and thieno[2,3-C]pyridine-3-formaldehyde forms a larger conjugated system, expands the ultraviolet absorption range, and makes the toughening agent have stronger ultraviolet absorption; then 3,4,5-trimethoxybenzene acetic acid is used to form polyphenol hydroxyl in the toughening agent, enhance the free radical scavenging capacity, and synergistically endow the toughening agent with stronger anti-ultraviolet aging performance, thereby improving the aging resistance of the PET film. In addition, the alcohol hydroxyl formed in the toughening agent by the reaction enhances the compatibility of the toughening agent with the tackifier and the PET resin, thereby further improving the toughness of the PET film. The improvement of the compatibility of the toughening agent with the flame retardant also helps to improve the stability of the small molecule flame retardant in the matrix. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0044] Embodiment 1

[0045] A toughening agent, the preparation thereof comprises the following steps:

[0046] Step A1: 9H-carbazole-3-cyano, epichlorohydrin, tetramethylammonium bromide, toluene are mixed and stirred for 25 min, and then stirred at 80℃ for 3.5 h. After cooling to room temperature, potassium carbonate solution is added, and then stirred for 5.5 h to obtain product p1. Thieno[2,3-C]pyridine-3-formaldehyde, propionic anhydride, anhydrous sodium carbonate are mixed and stirred for 15 min, and then heated to 100℃ and stirred under reflux for 2 h to obtain product p2. The amount ratio of 9H-carbazole-3-cyano, epichlorohydrin, tetramethylammonium bromide, toluene and potassium carbonate solution is 21 g:14 g:3.1 g:80 mL:18 mL. The mass fraction of potassium carbonate solution is 35%. The amount ratio of thieno[2,3-C]pyridine-3-formaldehyde, propionic anhydride and anhydrous sodium carbonate is 18 g:14 g:2 g.

[0047] Step A2: product p2, toluene were mixed and stirred for 5 min, and then heated to 50°C, product p1 and 4-methylpyridine were added, and stirred for 7.5 h, and then heated to 100°C, and stirred for 2 h to obtain product p3; the amount ratio of product p2, toluene, 4-methylpyridine, product p1 was 25 g: 120 mL: 2 g: 32 g;

[0048] Step A3: 3,4,5-trimethoxyphenylacetic acid was added to toluene and stirred for 10 min, and then nitrogen was introduced, and oxalyl chloride and DMF were added under ice water bath, and then heated to room temperature, and stirred for 1.5 h to obtain product p4; product p3, 4-dimethylaminopyridine, potassium carbonate and DMSO were mixed and stirred for 20 min, and then a solution of product p4 was added under ice water bath, and then heated to 45°C, and stirred for 8.5 h to obtain product p5; the amount ratio of 3,4,5-trimethoxyphenylacetic acid, toluene, oxalyl chloride and DMF was 24 g: 90 mL: 20 g: 0.9 g; the amount ratio of product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO and the solution of product p4 was 58 g: 2.5 g: 14.5 g: 135 mL: 90 mL; the solution of product p4 was obtained by stirring 28 g of product p4 and 60 mL of DMSO;

[0049] Step A4: product p5, dioxane and ethyl acetate were mixed and stirred for 30 min, and then palladium-carbon was added and hydrogen was introduced, and then heated to 70°C, and ammonia water was added, and stirred for 5 h to obtain product p6; product p6, glycidyl methacrylate and tetrahydrofuran were mixed and heated to 55°C, and then reacted for 24 h to obtain product p7; the amount ratio of product p5, dioxane, ethyl acetate, palladium-carbon and ammonia water was 88 g: 90 mL: 80 mL: 1.5 g: 10 mL; the pressure of hydrogen was controlled to be 2 MPa; the amount ratio of product p6, glycidyl methacrylate and tetrahydrofuran was 85 g: 15 g: 180 mL;

[0050] Step A5: product p7, glacial acetic acid and aqueous hydrogen bromide were mixed, and then refluxed and stirred at 100°C for 11 h, and then the pH was adjusted to 7.9 to obtain product p8; EVA, product p8, styrene and potassium persulfate were placed in a single screw extruder, and then melt-extruded at 150°C and 90 r / min, and then vacuum-dried at 50°C to obtain a toughening agent; the amount ratio of product p7, glacial acetic acid and aqueous hydrogen bromide was 9.2 g: 360 mL: 340 mL; the mass fraction of aqueous hydrogen bromide was 45%; the amount ratio of EVA, product p8, 4-methylstyrene and potassium persulfate was 100 g: 5 g: 4.5 g: 0.25 g.

[0051] Example 2

[0052] A toughening agent, the preparation comprising the following steps:

[0053] Step A1: 9H-carbazole-3-carbonitrile, epichlorohydrin, tetramethylammonium bromide, toluene were mixed and stirred for 30 min, and stirred at 85°C for 4.0 h. After cooling to room temperature, potassium carbonate solution was added, and stirred for 6.0 h to obtain product p1. Thieno[2,3-C]pyridine-3-carboxaldehyde, propionic anhydride, anhydrous sodium carbonate were mixed and stirred for 18 min, and heated to 105°C, and stirred at reflux for 2.3 h to obtain product p2. The amount ratio of 9H-carbazole-3-carbonitrile, epichlorohydrin, tetramethylammonium bromide, toluene, potassium carbonate solution was 22 g: 15 g: 3.3 g: 85 mL: 20 mL. The mass fraction of potassium carbonate solution was 40%. The amount ratio of thieno[2,3-C]pyridine-3-carboxaldehyde, propionic anhydride, anhydrous sodium carbonate was 19 g: 15 g: 2.5 g;

[0054] Step A2: Product p2, toluene were mixed and stirred for 8 min, and heated to 53°C. 4-Methylpyridine, product p1 were added, and stirred for 8.0 h. Then heated to 105°C, and stirred for 2.3 h to obtain product p3. The amount ratio of product p2, toluene, 4-methylpyridine, product p1 was 26 g: 125 mL: 2.3 g: 33 g.

[0055] Step A3: 3,4,5-Trimethoxybenzeneacetic acid was added to toluene and stirred for 13 min. Nitrogen was introduced, and oxalyl chloride and DMF were added under ice water bath. After heating to room temperature, stirred for 1.8 h to obtain product p4. Product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO were mixed and stirred for 23 min under ice water bath. A solution of product p4 was added, and heated to 48°C. After stirring for 8.8 h, product p5 was obtained. The amount ratio of 3,4,5-trimethoxybenzeneacetic acid, toluene, oxalyl chloride, DMF was 25 g: 95 mL: 21 g: 1.0 g. The amount ratio of product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO, solution of product p4 was 59 g: 2.8 g: 15.0 g: 140 mL: 93 mL. The solution of product p4 was obtained by stirring 29 g of product p4 and 65 mL of DMSO.

[0056] Step A4: Product p5, dioxane, ethyl acetate were mixed and stirred for 33 min. Palladium-carbon was added, and hydrogen was introduced. After heating to 75°C, ammonia water was added, and stirred for 5.3 h to obtain product p6. Product p6, glycidyl methacrylate, tetrahydrofuran were mixed and stirred, and heated to 60°C. After constant temperature reaction for 24.5 h, product p7 was obtained. The amount ratio of product p5, dioxane, ethyl acetate, palladium-carbon, ammonia water was 89 g: 95 mL: 85 mL: 1.8 g: 13 mL. The pressure of hydrogen was controlled at 2 MPa. The amount ratio of product p6, glycidyl methacrylate, tetrahydrofuran was 86 g: 16 g: 185 mL.

[0057] Step A5: product p7, glacial acetic acid, aqueous hydrogen bromide solution were mixed and stirred at reflux at 105°C for 11.5h, the pH was adjusted to 8.0 to obtain product p8; EVA, product p8, styrene and potassium persulfate were placed in a single screw extruder and melt extruded at 155°C and 90r / min, and then vacuum dried at 55°C to obtain a toughening agent; the amount ratio of product p7, glacial acetic acid, aqueous hydrogen bromide solution was 9.3g: 365mL: 345mL; the mass fraction of aqueous hydrogen bromide solution was 50%; the amount ratio of EVA, product p8, 4-methylstyrene and potassium persulfate was 102g: 5.5g: 4.8g: 0.30g.

[0058] Example 3

[0059] A toughening agent, the preparation comprising the following steps:

[0060] Step A1: 9H-carbazole-3-cyano, epichlorohydrin, tetramethylammonium bromide, toluene were mixed and stirred for 35min, and stirred at 90°C for 4.5h, then potassium carbonate solution was added after cooling to room temperature, and stirred for another 6.5h to obtain product p1; thieno[2,3-C]pyridine-3-carboxaldehyde, propionic anhydride, anhydrous sodium carbonate were mixed and stirred for 20min, and then heated to 110°C and stirred at reflux for 2.5h to obtain product p2; the amount ratio of 9H-carbazole-3-cyano, epichlorohydrin, tetramethylammonium bromide, toluene, potassium carbonate solution was 23g: 16g: 3.5g: 90mL: 22mL; the mass fraction of potassium carbonate solution was 45%; the amount ratio of thieno[2,3-C]pyridine-3-carboxaldehyde, propionic anhydride, anhydrous sodium carbonate was 20g: 16g: 3g;

[0061] Step A2: product p2, toluene were mixed and stirred for 10min under nitrogen atmosphere, and then heated to 55°C, 4-methylpyridine and product p1 were added, and stirred for 8.5h, and then heated to 110°C and stirred for 2.5h to obtain product p3; the amount ratio of product p2, toluene, 4-methylpyridine, product p1 was 27g: 130mL: 2.5g: 34g;

[0062] Step A3: 3,4,5-trimethoxyphenylacetic acid was added into toluene and stirred for 15 min, nitrogen was bubbled, oxalyl chloride and DMF were added under ice water bath, the temperature was increased to room temperature, and the mixture was stirred for 2 h to obtain product p4; product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO were mixed and stirred for 25 min, a solution of product p4 was added under ice water bath, and the temperature was increased to 50℃, and the mixture was stirred for 9 h to obtain product p5; the amount ratio of 3,4,5-trimethoxyphenylacetic acid, toluene, oxalyl chloride, DMF was 26 g: 100 mL: 22 g: 1.1 g; the amount ratio of product p3, 4-dimethylaminopyridine, potassium carbonate, DMSO, solution of product p4 was 60 g: 3 g: 15.5 g: 145 mL: 95 mL; the solution of product p4 was obtained by mixing 30 g of product p4 and 70 mL of DMSO;

[0063] Step A4: product p5, dioxane, ethyl acetate were mixed and stirred for 35 min, palladium-carbon was added and hydrogen was bubbled, the temperature was increased to 80℃, and ammonia water was added, and the mixture was stirred for 5.5 h to obtain product p6; product p6, glycidyl methacrylate, tetrahydrofuran were mixed and stirred, and the temperature was increased to 65℃, and the mixture was kept at the temperature for 25 h to obtain product p7; the amount ratio of product p5, dioxane, ethyl acetate, palladium-carbon, ammonia water was 90 g: 100 mL: 90 mL: 2 g: 15 mL; the pressure of hydrogen was controlled at 2 MPa; the amount ratio of product p6, glycidyl methacrylate, tetrahydrofuran was 87 g: 17 g: 190 mL;

[0064] Step A5: product p7, glacial acetic acid, aqueous hydrogen bromide solution were mixed, and the mixture was stirred under reflux at 110℃ for 12 h, and the pH was adjusted to 8.2 to obtain product p8; EVA, product p8, styrene and potassium persulfate were placed in a single screw extruder, and the mixture was melt-extruded at 160℃ and 100 r / min, and then vacuum dried at 60℃ to obtain a toughening agent; the amount ratio of product p7, glacial acetic acid, aqueous hydrogen bromide solution was 9.4 g: 370 mL: 350 mL; the mass fraction of aqueous hydrogen bromide solution was 55%; the amount ratio of EVA, product p8, 4-methylstyrene and potassium persulfate was 104 g: 6 g: 5 g: 0.35 g.

[0065] Example 4

[0066] A high-toughness PET film, comprising the following raw materials by weight: 90 parts of PET resin, 5 parts of tackifier, 1 part of flame retardant, 1 part of plasticizer, 1.5 parts of toughening agent, 0.6 parts of lubricant, and 0.2 parts of nucleating agent; the tackifier is EVA-g-MAH (supplier: Dongguan Shangyi Plastic Co., Ltd., brand: 11D554); the flame retardant is flame retardant DOPO-ITA; the plasticizer is a mixture of diisooctyl phthalate and dioctyl phthalate in a mass ratio of 2:1; the lubricant is a mixture of ethylene bisoleic acid amide and paraffin in a mass ratio of 1:1.5; and the nucleating agent is talc.

[0067] The preparation of the high-toughness PET film comprises the following specific steps:

[0068] The PET resin, the tackifier, the flame retardant, the plasticizer, the toughening agent obtained in Example 1, the lubricant, and the nucleating agent are mixed and stirred for 1 h, granulated at 80℃ to obtain granules, dried at 155℃ for 4 h, then transferred to a twin-screw extruder for melt extrusion at 285℃, then cast into a sheet at 28℃, then stretched, and finally heat set at 230℃ for 15 s to obtain the high-toughness PET film; the stretching process comprises longitudinal stretching and transverse stretching; the longitudinal stretching conditions are a temperature of 115℃ and a stretching ratio of 3; and the transverse stretching conditions are a temperature of 120℃ and a stretching ratio of 4.

[0069] Example 5

[0070] A high-toughness PET film, comprising the following raw materials by weight: 93 parts of PET resin, 8 parts of tackifier, 1.5 parts of flame retardant, 1.3 parts of plasticizer, 1.8 parts of toughening agent, 0.7 parts of lubricant, and 0.3 parts of nucleating agent; the tackifier is EVA-g-MAH (supplier: Dongguan Shangyi Plastic Co., Ltd., brand: 11D554); the flame retardant is flame retardant DOPO-ITA; the plasticizer is a mixture of diisooctyl phthalate and dioctyl phthalate in a mass ratio of 2.3:1.3; the lubricant is a mixture of ethylene bisoleic acid amide and paraffin in a mass ratio of 1.3:1.8; and the nucleating agent is talc.

[0071] The preparation of the high-toughness PET film comprises the following specific steps:

[0072] PET resin, tackifier, flame retardant, plasticizer, toughening agent obtained in Example 2, lubricant, nucleating agent were mixed and stirred for 1.3 h, and granulated at 85 ℃ to obtain granules; the granules were dried at 160 ℃ for 4.3 h, then transferred to a twin-screw extruder for melt extrusion at 290 ℃, then cast at 30 ℃, then stretch treated, and finally heat set at 235 ℃ for 20 s to obtain a high-toughness PET film; the stretch treatment included longitudinal stretching and transverse stretching; the longitudinal stretching conditions were a temperature of 120 ℃ and a stretching ratio of 3.5; the transverse stretching conditions were a temperature of 125 ℃ and a stretching ratio of 4.5.

[0073] Example 6

[0074] A high-toughness PET film, comprising the following raw materials by weight: PET resin 95 parts, tackifier 10 parts, flame retardant 2 parts, plasticizer 1.5 parts, toughening agent 2 parts, lubricant 0.8 parts, nucleating agent 0.4 parts; the tackifier is EVA-g-MAH (supplier: Dongguan Shangyi Plastic Co., Ltd., brand: 11D554); the flame retardant is flame retardant DOPO-ITA; the plasticizer is diisooctyl phthalate and dioctyl phthalate mixed in a mass ratio of 2.5:1.5; the lubricant is ethylene bisoleic acid amide and paraffin wax mixed in a mass ratio of 1.5:2; the nucleating agent is talc;

[0075] The preparation of the high-toughness PET film includes the following specific steps:

[0076] PET resin, tackifier, flame retardant, plasticizer, toughening agent obtained in Example 3, lubricant, nucleating agent were mixed and stirred for 1.5 h, and granulated at 90 ℃ to obtain granules; the granules were dried at 165 ℃ for 4.5 h, then transferred to a twin-screw extruder for melt extrusion at 295 ℃, then cast at 32 ℃, then stretch treated, and finally heat set at 240 ℃ for 25 s to obtain a high-toughness PET film; the stretch treatment included longitudinal stretching and transverse stretching; the longitudinal stretching conditions were a temperature of 125 ℃ and a stretching ratio of 4; the transverse stretching conditions were a temperature of 130 ℃ and a stretching ratio of 5.

[0077] Comparative Example 1

[0078] Comparing with Example 6, 9H-carbazole-3-cyanide in the preparation process of the toughening agent was replaced by N-methyl-4-cyanophenylamine, and the rest was exactly the same as Example 6 to prepare a PET film.

[0079] Comparative Example 2

[0080] Comparing with Example 6, thieno[2,3-C]pyridine-3-formaldehyde in the preparation process of the toughening agent was replaced by 3-thiophene formaldehyde, and the rest was exactly the same as Example 6 to prepare a PET film.

[0081] Comparative Example 3

[0082] Comparing with Example 6, the reaction of glycidyl methacrylate in the process of toughening agent preparation was replaced by the reaction of methacryloyl chloride with product p6, and the obtained product p7-1 instead of product p7 was used in the subsequent reaction, and the rest was exactly the same as Example 6 to prepare PET film.

[0083] The reaction of methacryloyl chloride with product p6 was as follows: product p6, sodium carbonate, dimethyl sulfoxide were mixed, and methacryloyl chloride solution was added under stirring in an ice water bath, and the temperature was raised to 40℃, and the reaction was stirred for 5.5h to obtain product p7-1; the amount ratio of product p6, sodium carbonate, dimethyl sulfoxide, methacryloyl chloride solution was 87g:2.2g:180mL:60mL; the amount ratio of methacryloyl chloride and dimethyl sulfoxide in the methacryloyl chloride solution was 16g:40mL;

[0084] The PET film prepared by the present application was further tested for effect, and the test results are as follows.

[0085] Elongation at break: the elongation at break of the obtained PET film was tested to evaluate the toughness of the PET film according to GB / T1040.3-2006 "Determination of tensile properties of plastics-Part 3: test conditions for films and sheets" standard;

[0086] Anti-UV aging property: the obtained PET film was placed in a UV aging test box, and the UV accelerated aging test was carried out according to the method described in ISO 4892.3 "Plastics- Methods of exposure to laboratory light sources- Part 3: Fluorescent UV lamps", and the test conditions were as follows: light source: UVA-340; radiation energy: 0.83W / (m 2 nm); test temperature: 70℃; every 4h of continuous light, 1h of light off, cyclic test for 50h; and the retention rate of elongation at break after UV accelerated aging was tested to evaluate the aging resistance;

[0087] The results are recorded in Table 1;

[0088] Table 1 test results

[0089]

[0090]

[0091] According to the data in Table 1, the PET film of the present invention has high toughness and strong aging resistance. Comparing Example 9 with Comparative Example 1, it can be seen that when the 9H-carbazole-3-cyano group in the toughening agent preparation process is replaced with N-methyl-4-cyanoaniline, the ultraviolet absorption ability of the toughening agent is weakened, and the aging resistance of the resulting PET film is reduced. Comparing Example 9 with Comparative Example 2, it can be seen that when the thieno[2,3-C]pyridine-3-carboxaldehyde in the toughening agent preparation process is replaced with 3-thiophenecarboxaldehyde, the ultraviolet absorption ability of the toughening agent is weakened, and the aging resistance of the resulting PET film is reduced. Comparing Example 9 with Comparative Example 3, it can be seen that when the reaction of glycidyl methacrylate and product p7 in the toughening agent preparation process is replaced with the reaction of methacryloyl chloride and product p7, the compatibility of the toughening agent with the tackifier and PET resin is reduced, and the aging resistance and toughness of the resulting PET film are reduced.

[0092] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A high-toughness PET film, characterized by: The composition comprises the following raw materials in parts by weight: 90-95 parts of PET resin, 5-10 parts of tackifier, 1-2 parts of flame retardant, 1-1.5 parts of plasticizer, 1.5-2 parts of toughening agent, 0.6-0.8 parts of lubricant, and 0.2-0.4 parts of nucleating agent; The preparation of the toughening agent comprises the following steps: Step A1: Mix cyanocarbazole, epichlorohydrin, tetramethylammonium bromide, and toluene, heat to react, cool, add potassium carbonate solution, and stir to obtain product p1; mix aromatic formaldehyde, propionic anhydride, and anhydrous sodium carbonate, heat to reflux with stirring to obtain product p2; Step A2: In a protective gas atmosphere, product p2 and toluene are mixed, 4-methylpyridine and product p1 are added at a high temperature, the mixture is stirred for reaction, and the mixture is heated again with stirring to obtain product p3; Step A3: Add 3,4,5-trimethoxyphenylacetic acid to toluene with stirring, introduce protective gas, add oxalyl chloride and DMF in an ice-water bath, warm to room temperature, and stir to obtain product p4; mix product p3, 4-dimethylaminopyridine, potassium carbonate, and DMSO, add the solution of product p4 in an ice-water bath, and heat and stir again to obtain product p5; Step A4: Mix product p5, dioxane, and ethyl acetate, add palladium on carbon, and introduce hydrogen. After heating, add aqueous ammonia and stir to obtain product p6. Mix product p6, methacrylate, and tetrahydrofuran while stirring and heating, and react at a constant temperature to obtain product p7. Step A5: Mix product p7, glacial acetic acid, and hydrobromic acid aqueous solution, heat under reflux with stirring, and adjust the pH to obtain product p8; mix EVA, product p8, styrene, and initiator and melt extrude to obtain a toughening agent.

2. The high-toughness PET film according to claim 1, characterized in that: In step A1, the cyano-containing carbazole is 9H-carbazole-3-cyano.

3. The high-toughness PET film according to claim 1, characterized in that: In step A1, the aromatic formaldehyde is thieno[2,3-C]pyridine-3-carbaldehyde.

4. The high-toughness PET film according to claim 1, characterized in that: In step A4, the methacrylate is glycidyl methacrylate.

5. A method for preparing the high-toughness PET film according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: mixing PET resin, tackifier, flame retardant, plasticizer, toughening agent, lubricant and nucleating agent to obtain pellets; drying the pellets, transferring the pellets to a twin-screw extruder for melt extrusion, casting sheets, stretching treatment and finally heat setting to obtain a high-toughness PET film.

6. The method for preparing a high-toughness PET film according to claim 5, wherein: The temperature for mixing and granulation is 80-90°C; the temperature for melt extrusion is 285-295°C; and the temperature for casting is 28-32°C.

7. The method for preparing a high-toughness PET film according to claim 5, wherein: The stretching treatment includes longitudinal stretching and transverse stretching; the conditions for longitudinal stretching are: temperature of 115-125°C and stretching ratio of 3-4; the conditions for transverse stretching are: temperature of 120-130°C and stretching ratio of 4-5; the heat setting method is: heat setting at 230-240°C for 15-25s.

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