Polyester-based high-toughness plastic sheet and preparation method thereof

Abstract

The invention discloses a polyester-based high-toughness plastic sheet and a preparation method thereof, and belongs to the technical field of high polymer material preparation, the polyester-based high-toughness plastic sheet comprises modified polyester resin, a first modifier and a second modifier, the modified polyester resin is prepared from unsaturated alkenyl dianhydride and dihydroxy crown ether as raw materials through dehydration condensation ester, the first modifier is alkyl phenyl ether of double-end-group secondary ammonium salt, and the second modifier is 2, 2 '-(1, 2-ethanedioxy) diethyl mercaptan with double-end-group sulfydryl; according to the polyester-based high-toughness plastic sheet provided by the invention, through a reasonable modification method, the toughness can be improved on the premise of not obviously sacrificing other properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material preparation, and particularly relates to a polyester-based high-toughness plastic sheet and a preparation method thereof. Background Art

[0002] Polyester plastics (such as PET, PBT, etc.) are widely used in fields such as packaging, textiles, electronics and electrical appliances, and the automotive industry due to their excellent mechanical strength, chemical corrosion resistance, and processing performance. However, their inherent brittle defects (such as low impact strength and insufficient elongation at break) severely restrict their applications under dynamic load impact or low-temperature environments. Unmodified polyester plastics are prone to brittle fracture when subjected to external force impact, resulting in the rupture of packaging containers or the failure of automotive components. Therefore, toughening modification has become an important technical means to improve the comprehensive performance of polyester plastics and expand their application scope.

[0003] The rigidity and high crystallinity of the polyester molecular chain lead to insufficient toughness of the material. Existing toughening modification methods mainly include elastomer blending, such as POE, EPDM, etc.; particle filling, such as montmorillonite, silica, etc.; and chemical modification, such as copolymerization to introduce flexible chain segments. Among them, elastomer blending introduces a flexible phase or energy dissipation structure to improve its notched impact strength, with a relatively low cost, but poor compatibility. Particle filling can inhibit crack propagation, with high requirements for dispersion, and also has the problem of poor compatibility. Chemical modification generally introduces flexible chain segments through copolymerization, and the modification process is relatively complex. Moreover, the above toughening modification methods do not balance the performance of strength and toughness, and their toughening is achieved at the expense of strength, making it difficult to maintain its mechanical strength while improving toughness. Summary of the Invention

[0004] In view of at least one of the above problems, the present invention provides a polyester-based high-toughness plastic sheet and a preparation method thereof.

[0005] The object of the present invention is achieved by the following technical solutions:

[0006] A polyester-based high-toughness plastic sheet, comprising a modified polyester resin, a first modifier, and a second modifier. The preparation method of the modified polyester resin comprises the following steps:

[0007] Weigh norbornene dianhydride and dissolve it in dichloromethane solvent, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine, fully stir and mix, then add dihydroxy-dibenzo-24-crown-8, stir and react at room temperature for 4 - 8 h, and remove the solvent by reduced pressure evaporation to obtain the modified polyester resin;

[0008] The preparation method of the first modifier comprises the following steps:

[0009] (1) Weigh p-hydroxybenzaldehyde and dissolve it in acetone solvent. Add 1,10-dibromodecane. After fully stirring and mixing, add potassium carbonate and sodium iodide. Heat under reflux in a protective atmosphere for 10 - 20 h. After cooling, remove the precipitate. Evaporate the solvent and then dissolve it in dichloromethane. Wash it successively with water and saturated brine. After drying the organic phase, evaporate the solvent to obtain the intermediate product;

[0010] (2) Mix the intermediate product and ethylamine and dissolve them in ethanol solvent. Heat under reflux for 10 - 18 h. After cooling, add sodium borohydride and stir at room temperature for 5 - 10 h. Add deionized water to terminate the reaction. Extract with dichloromethane. After drying the organic phase, evaporate the solvent. Dissolve it in acetone. Add concentrated hydrochloric acid and stir and mix. Then add saturated ammonium hexafluorophosphate solution. Stir at room temperature for 1 - 4 h. Extract with dichloromethane. After drying the organic phase, evaporate the solvent to obtain the first modifier;

[0011] The second modifier is 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan).

[0012] In some preferred embodiments, the mass ratio of the modified polyester resin, the first modifier, and the second modifier is 100:(1 - 6):(0.5 - 4).

[0013] In some preferred embodiments, the mass ratio of the norbornene dianhydride, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 4-dimethylaminopyridine, and dihydroxy-dibenzo-24-crown-8 is 1:(0.9 - 1):(0.14 - 0.24):(2.4 - 3.8).

[0014] In some preferred embodiments, the mass ratio of the p-hydroxybenzaldehyde, 1,10-dibromodecane, potassium carbonate, and sodium iodide in step (1) is 1:(0.9 - 2):(2.2 - 3.6):(0.12 - 0.28).

[0015] In some preferred embodiments, the mass ratio of the intermediate product, ethylamine, sodium borohydride, concentrated hydrochloric acid, and ammonium hexafluorophosphate in step (2) is 1:(0.2 - 0.32):(0.25 - 0.39):(0.04 - 0.14):(0.25 - 0.39).

[0016] In some preferred embodiments, it includes a polyester resin. The polyester resin is a polymerization product of a dibasic acid and a diol. The mass ratio of the polyester resin in the polyester-based high-toughness plastic sheet is 15 - 55%.

[0017] In some preferred embodiments, the polyester resin is one or more of polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester, and polyethylene terephthalate-neopentyl glycol ester.

[0018] In some preferred embodiments, it includes additives, and the mass ratio of the additives in the polyester-based high-toughness plastic sheet is 0.1-2%.

[0019] In some preferred embodiments, the additives are one or more of antioxidants, lubricants, plasticizers, and fillers.

[0020] In some preferred embodiments, the antioxidant is antioxidant 1010, antioxidant 1076, antioxidant 1035, antioxidant 2103, antioxidant 168, antioxidant 164, or antioxidant 626; the lubricant is vinyl bisstearamide or polyethylene wax; the plasticizer is phthalate, citrate, or chlorinated paraffin; the filler is montmorillonite or nano-silica.

[0021] Another aspect of the present invention is to provide a method for preparing the polyester-based high-toughness plastic sheet, which includes the following steps:

[0022] Dissolve the modified polyester resin, the first modifier, the second modifier, and the polyester resin in dichloromethane solvent, stir and mix under ultraviolet light conditions for 0.5-2 h. After the reaction is completed, evaporate the solvent. After the product is mixed evenly with the additives, it is kneaded, melt-extruded, and then calendered and cooled to obtain a sheet. The temperature of the melt extrusion is 240-260 °C.

[0023] In some preferred embodiments, the wavelength of the ultraviolet light is 300-400 nm, and the irradiation intensity is 4-70 mW / cm 2 .

[0024] The beneficial effects of the present invention are:

[0025] In view of the problem that the toughening methods in the prior art usually have difficulty in maintaining the mechanical strength while improving the toughness, the present invention provides a polyester-based high-toughness plastic sheet. Through a reasonable modification method, the toughness can be improved without significantly sacrificing other properties, meeting the requirements of the packaging protection field for the strength and toughness properties of polyester materials. Through toughening modification, polyester plastics can be applied on a large scale in more high-value-added fields. Specifically, on the basis of polyester resin, the present invention toughens and modifies it through blending modified resin, the first / second modifiers. Among them, the modified polyester resin is prepared by dehydration condensation to form an ester using unsaturated alkenyl dianhydride and dihydroxy crown ether as raw materials. The first modifier is an alkyl phenyl ether of bis-terminal secondary ammonium salt, and the second modifier is 2,2'-(1,2-ethylenedioxydioxy) bis-ethyl mercaptan with bis-terminal mercapto groups. The second modifier crosslinks with the unsaturated double bonds in the modified polyester resin through a thiol-ene click reaction to provide good mechanical strength for the resin. At the same time, by utilizing the host-guest recognition between the secondary ammonium salt and the crown ether macrocycle, soft crosslinking points are constructed between the modified polyester resin and the bis-terminal secondary ammonium salt of the first modifier to provide good impact resistance for the resin. Detailed implementation mode

[0026] The present invention will be further described in conjunction with the following embodiments.

[0027] Embodiment 1

[0028] A polyester-based high-toughness plastic sheet, comprising polyester resin, modified polyester resin, a first modifier and a second modifier;

[0029] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300 °C / 1.2 kg);

[0030] The preparation method of the modified polyester resin comprises the following steps:

[0031] Weigh norbornene dianhydride and dissolve it in dichloromethane solvent, add 1-ethyl-(3-dimethylaminopropyl) carbodiimide and 4-dimethylaminopyridine, fully stir and mix, then add dihydroxy-dibenzo-24-crown-8, and stir and react at room temperature for 6 h. After evaporating the solvent under reduced pressure, the modified polyester resin is obtained; the mass ratio of the norbornene dianhydride to the 1-ethyl-(3-dimethylaminopropyl) carbodiimide, the 4-dimethylaminopyridine, and the dihydroxy-dibenzo-24-crown-8 is 1:0.96:0.18:2.9;

[0032] The preparation method of the first modifier comprises the following steps:

[0033] (1) Weigh p-hydroxybenzaldehyde and dissolve it in acetone solvent. Add 1,10-dibromodecane. After fully stirring and mixing, add potassium carbonate and sodium iodide. Heat and reflux for 14 h under a protective atmosphere. After cooling, remove the precipitate. Evaporate the solvent and dissolve the residue in dichloromethane. Wash it successively with water and saturated brine. After drying the organic phase with anhydrous sodium sulfate, evaporate the solvent under reduced pressure to obtain the intermediate product. The mass ratio of p-hydroxybenzaldehyde to 1,10-dibromodecane, potassium carbonate, and sodium iodide is 1:1.2:2.8:0.18;

[0034] (2) Mix the intermediate product and ethylamine and dissolve them in ethanol solvent. Heat and reflux for 14 h. After cooling, add sodium borohydride and stir at room temperature for 6 h. Add deionized water to terminate the reaction. Extract with dichloromethane. After drying the organic phase with anhydrous sodium sulfate, evaporate the solvent under reduced pressure. Dissolve the residue in acetone. Add concentrated hydrochloric acid and stir and mix. Then add saturated ammonium hexafluorophosphate solution. Stir at room temperature for 2 h. Extract with dichloromethane. After drying the organic phase with anhydrous sodium sulfate, evaporate the solvent under reduced pressure to obtain the first modifier. The concentrated hydrochloric acid is commercially available hydrochloric acid with a mass fraction of 36 - 38%; The mass ratio of the intermediate product to ethylamine, sodium borohydride, concentrated hydrochloric acid, and ammonium hexafluorophosphate is 1:0.25:0.3:0.09:0.3;

[0035] The second modifier is 2,2'-(1,2-ethanediyl dioxy)bis(ethanethiol);

[0036] The mass ratio of the polyester resin to the modified polyester resin, the first modifier, and the second modifier is 70:100:4:2.8;

[0037] The preparation method of the polyester-based high-toughness plastic sheet includes the following steps:

[0038] Mix the polyester resin, the modified polyester resin, the first modifier, and the second modifier and dissolve them in dichloromethane solvent. Stir and mix under ultraviolet light conditions for 1 h. After the reaction is completed, evaporate the solvent. The product is melt-extruded and then calendered and cooled to obtain a sheet. The thickness of the sheet is 0.4 mm;

[0039] The temperature of the melt extrusion is 240 - 260 °C;

[0040] The wavelength of the ultraviolet light is 360 nm, and the irradiation intensity is 20 mW / cm 2 .

[0041] Example 2

[0042] A polyester-based high-toughness plastic sheet, comprising a polyester resin, a first modifier, and a second modifier;

[0043] The polyester resin is polyethylene terephthalate with a melt index of 26.8 g / 10 min (300 °C / 1.2 kg);

[0044] The preparation method of the first modifier comprises the following steps:

[0045] (1) Weigh p-hydroxybenzaldehyde and dissolve it in an acetone solvent. Add 1,10-dibromodecane. After fully stirring and mixing, add potassium carbonate and sodium iodide. Heat under reflux for 14 h under a protective atmosphere. After cooling, remove the precipitate. Evaporate the solvent and then dissolve it in dichloromethane. Wash successively with water and saturated brine. The organic phase is dried over anhydrous sodium sulfate and then the solvent is removed by distillation under reduced pressure to obtain an intermediate product; the mass ratio of p-hydroxybenzaldehyde to 1,10-dibromodecane, potassium carbonate, and sodium iodide is 1:1.2:2.8:0.18;

[0046] (2) Mix the intermediate product and ethylamine and dissolve them in an ethanol solvent. Heat under reflux for 14 h. After cooling, add sodium borohydride and stir and react at room temperature for 6 h. Add deionized water to terminate the reaction. Extract with dichloromethane. The organic phase is dried over anhydrous sodium sulfate and then the solvent is removed by distillation under reduced pressure. Dissolve it in acetone. Add concentrated hydrochloric acid and stir and mix, then add a saturated ammonium hexafluorophosphate solution. Stir and react at room temperature for 2 h. Extract with dichloromethane. The organic phase is dried over anhydrous sodium sulfate and then the solvent is removed by distillation under reduced pressure to obtain the first modifier; the concentrated hydrochloric acid is commercially available hydrochloric acid with a mass fraction of 36 - 38%; the mass ratio of the intermediate product to ethylamine, sodium borohydride, concentrated hydrochloric acid, and ammonium hexafluorophosphate is 1:0.25:0.3:0.09:0.3;

[0047] The second modifier is 2,2'-(1,2-ethylenedioxy)bis(ethanethiol);

[0048] The mass ratio of the polyester resin to the first modifier and the second modifier is 70:4:2.8;

[0049] The preparation method of the polyester-based high-toughness plastic sheet is the same as that in Example 1.

[0050] Example 3

[0051] A polyester-based high-toughness plastic sheet, comprising a polyester resin, a modified polyester resin, and a second modifier;

[0052] The polyester resin is polyethylene terephthalate with a melt index of 26.8 g / 10 min (300 °C / 1.2 kg);

[0053] The preparation method of the modified polyester resin comprises the following steps:

[0054] Weigh norbornene dianhydride and dissolve it in dichloromethane solvent. Add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine. After stirring and mixing well, add dihydroxy-dibenzo-24-crown-8. Stir and react at room temperature for 6 h. After removing the solvent under reduced pressure, a modified polyester resin is obtained. The mass ratio of norbornene dianhydride to 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 4-dimethylaminopyridine, and dihydroxy-dibenzo-24-crown-8 is 1:0.96:0.18:2.9;

[0055] The second modifier is 2,2'-(1,2-ethylenedioxy)bis(ethanethiol);

[0056] The mass ratio of the polyester resin to the modified polyester resin and the second modifier is 70:100:2.8;

[0057] The preparation method of the polyester-based high-toughness plastic sheet is the same as that in Example 1.

[0058] Example 4

[0059] A polyester-based high-toughness plastic sheet, comprising a polyester resin, a modified polyester resin, and a first modifier;

[0060] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300 °C / 1.2 kg);

[0061] The preparation method of the modified polyester resin comprises the following steps:

[0062] Weigh norbornene dianhydride and dissolve it in dichloromethane solvent. Add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine. After stirring and mixing well, add dihydroxy-dibenzo-24-crown-8. Stir and react at room temperature for 6 h. After removing the solvent under reduced pressure, a modified polyester resin is obtained. The mass ratio of norbornene dianhydride to 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 4-dimethylaminopyridine, and dihydroxy-dibenzo-24-crown-8 is 1:0.96:0.18:2.9;

[0063] The preparation method of the first modifier comprises the following steps:

[0064] (1) Weigh p-hydroxybenzaldehyde and dissolve it in acetone solvent. Add 1,10-dibromodecane. After fully stirring and mixing, add potassium carbonate and sodium iodide. Heat under reflux for 14 h in a protective atmosphere. After cooling, remove the precipitate. Evaporate the solvent and dissolve the residue in dichloromethane. Wash it successively with water and saturated brine. After drying the organic phase with anhydrous sodium sulfate, evaporate the solvent under reduced pressure to obtain the intermediate product. The mass ratio of p-hydroxybenzaldehyde to 1,10-dibromodecane, potassium carbonate, and sodium iodide is 1:1.2:2.8:0.18;

[0065] (2) Mix the intermediate product and ethylamine and dissolve them in ethanol solvent. Heat under reflux for 14 h. After cooling, add sodium borohydride and stir at room temperature for 6 h. Add deionized water to terminate the reaction. Extract with dichloromethane. After drying the organic phase with anhydrous sodium sulfate, evaporate the solvent under reduced pressure. Dissolve the residue in acetone. Add concentrated hydrochloric acid and stir and mix. Then add saturated ammonium hexafluorophosphate solution. Stir at room temperature for 2 h. Extract with dichloromethane. After drying the organic phase with anhydrous sodium sulfate, evaporate the solvent under reduced pressure to obtain the first modifier. The concentrated hydrochloric acid is commercially available hydrochloric acid with a mass fraction of 36 - 38%. The mass ratio of the intermediate product to ethylamine, sodium borohydride, concentrated hydrochloric acid, and ammonium hexafluorophosphate is 1:0.25:0.3:0.09:0.3;

[0066] The mass ratio of the polyester resin to the modified polyester resin and the first modifier is 70:100:4;

[0067] The preparation method of the polyester-based high-toughness plastic sheet is the same as that in Example 1.

[0068] Example 5

[0069] A polyester-based high-toughness plastic sheet, comprising a polyester resin, a modified polyester resin, a first modifier, a second modifier, and an antioxidant;

[0070] The polyester resin is polyethylene terephthalate, and its melt index is 26.8 g / 10 min (300 °C / 1.2 kg);

[0071] The preparation method of the modified polyester resin includes the following steps:

[0072] Weigh norbornene dianhydride and dissolve it in dichloromethane solvent. Add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine. After fully stirring and mixing, add dihydroxy-dibenzo-24-crown-8. Stir at room temperature for 6 h. Evaporate the solvent under reduced pressure to obtain the modified polyester resin. The mass ratio of norbornene dianhydride to 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 4-dimethylaminopyridine, and dihydroxy-dibenzo-24-crown-8 is 1:0.9:0.2:3.2;

[0073] The preparation method of the first modifier comprises the following steps:

[0074] (1) Weigh p-hydroxybenzaldehyde and dissolve it in acetone solvent. Add 1,10-dibromodecane. After fully stirring and mixing, add potassium carbonate and sodium iodide. Heat under reflux for 14 h in a protective atmosphere. After cooling, remove the precipitate. Evaporate the solvent and dissolve the residue in dichloromethane. Wash successively with water and saturated brine. Dry the organic phase over anhydrous sodium sulfate and then evaporate the solvent under reduced pressure to obtain an intermediate product. The mass ratio of p-hydroxybenzaldehyde to 1,10-dibromodecane, potassium carbonate, and sodium iodide is 1:1:3:0.2;

[0075] (2) Mix the intermediate product and ethylamine and dissolve them in ethanol solvent. Heat under reflux for 14 h. After cooling, add sodium borohydride and stir at room temperature for 6 h. Add deionized water to terminate the reaction. Extract with dichloromethane. Dry the organic phase over anhydrous sodium sulfate and then evaporate the solvent under reduced pressure. Dissolve the residue in acetone. Add concentrated hydrochloric acid and stir and mix well. Then add saturated ammonium hexafluorophosphate solution and stir at room temperature for 2 h. Extract with dichloromethane. Dry the organic phase over anhydrous sodium sulfate and then evaporate the solvent under reduced pressure to obtain the first modifier. The concentrated hydrochloric acid is commercially available hydrochloric acid with a mass fraction of 36 - 38%; The mass ratio of the intermediate product to ethylamine, sodium borohydride, concentrated hydrochloric acid, and ammonium hexafluorophosphate is 1:0.3:0.25:0.1:0.25;

[0076] The second modifier is 2,2'-(1,2-ethylenedioxy)bis(ethanethiol);

[0077] The antioxidant is antioxidant 1010;

[0078] The mass ratio of the polyester resin to the modified polyester resin, the first modifier, the second modifier, and the antioxidant is 70:100:6:3:0.2;

[0079] The preparation method of the polyester-based high-toughness plastic sheet comprises the following steps:

[0080] Mix the polyester resin, the modified polyester resin, the first modifier, and the second modifier and dissolve them in dichloromethane solvent. Stir and mix for 1 h under ultraviolet light conditions. After the reaction is completed, evaporate the solvent. Mix the product evenly with the additives and then carry out kneading. After melt extrusion, calender and cool to obtain a sheet. The thickness of the sheet is 0.4 mm;

[0081] The temperature of the melt extrusion is 240 - 260 °C;

[0082] The wavelength of the ultraviolet light is 360 nm, and the irradiation intensity is 20 mW / cm 2 .

[0083] Taking the unmodified polyethylene terephthalate resin (melt index 26.8 g / 10 min (300 °C / 1.2 kg)) as a control, the mechanical properties of the polyester-based high-toughness plastics prepared in Examples 1-5 were measured. Among them, the tensile strength was measured with reference to Standard ISO 527-1-2019; the flexural strength and flexural modulus were measured with reference to Standard ISO 178-2019; the notched impact strength was measured with reference to Standard ISO 179-1-2023; the reference standard ISO 1133-1-2022 was measured; the measurement results are shown in the following table:

[0084]

[0085] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polyester-based high-toughness plastic sheet, characterized in that, It includes a modified polyester resin, a first modifier and a second modifier. The preparation method of the modified polyester resin comprises the following steps: Weigh norbornene dianhydride and dissolve it in dichloromethane solvent. Add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine. After fully stirring and mixing, add dihydroxy-dibenzo-24-crown-8. Stir and react at room temperature for 4-8 h. After removing the solvent by reduced pressure distillation, the modified polyester resin is obtained; The preparation method of the first modifier comprises the following steps: (1) Weigh p-hydroxybenzaldehyde and dissolve it in acetone solvent. Add 1,10-dibromodecane. After fully stirring and mixing, add potassium carbonate and sodium iodide. Heat and reflux for 10-20 h under a protective atmosphere. After cooling, remove the precipitate. After evaporating the solvent, dissolve it with dichloromethane. Wash it successively with water and saturated brine. After drying the organic phase, evaporate the solvent to obtain an intermediate product; (2) Mix the intermediate product and ethylamine and dissolve them in ethanol solvent. Heat and reflux for 10-18 h. After cooling, add sodium borohydride and stir and react at room temperature for 5-10 h. Add deionized water to terminate the reaction. Extract with dichloromethane. After drying the organic phase, evaporate the solvent. Dissolve it with acetone. Add concentrated hydrochloric acid and stir and mix. Then add saturated ammonium hexafluorophosphate solution. Stir and react at room temperature for 1-4 h. Extract with dichloromethane. After drying the organic phase, evaporate the solvent to obtain the first modifier; The second modifier is 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan).

2. A polyester-based high-toughness plastic sheet according to claim 1, characterized in that, The mass ratio of the modified polyester resin to the first modifier and the second modifier is 100:(1-6):(0.5-4).

3. A polyester-based high-toughness plastic sheet according to claim 1, characterized in that, The mass ratio of the norbornene dianhydride to the 1-ethyl-(3-dimethylaminopropyl)carbodiimide, the 4-dimethylaminopyridine and the dihydroxy-dibenzo-24-crown-8 is 1:(0.9-1):(0.14-0.24):(2.4-3.8).

4. A polyester-based high-toughness plastic sheet according to claim 1, characterized in that, The mass ratio of the p-hydroxybenzaldehyde to the 1,10-dibromodecane, the potassium carbonate and the sodium iodide in step (1) is 1:(0.9-2):(2.2-3.6):(0.12-0.28).

5. A polyester-based high-toughness plastic sheet according to claim 1, characterized in that, The mass ratio of the intermediate product to the ethylamine, the sodium borohydride, the concentrated hydrochloric acid and the ammonium hexafluorophosphate in step (2) is 1:(0.2-0.32):(0.25-0.39):(0.04-0.14):(0.25-0.39).

6. A polyester-based high-toughness plastic sheet according to claim 1, wherein It includes a polyester resin which is a polymerization product of a dibasic acid and a diol. The mass ratio of the polyester resin in the polyester-based high-toughness plastic sheet is 15-55%.

7. A polyester-based high-toughness plastic sheet according to claim 1, characterized in that, The polyester resin is one or more of polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester, polyethylene terephthalate-neopentyl glycol ester.

8. A polyester-based high-toughness plastic sheet according to claim 1, wherein, It includes an additive. The mass ratio of the additive in the polyester-based high-toughness plastic sheet is 0.1-2%.

9. A polyester-based high-toughness plastic sheet according to claim 8, characterized in that, The additive is one or more of an antioxidant, a lubricant, a plasticizer, a filler.

10. The preparation method of a polyester-based high-toughness plastic sheet according to claim 8 or 9, characterized in that, It comprises the following steps: Dissolve the modified polyester resin, the first modifier, the second modifier, and the polyester resin in a dichloromethane solvent, stir and mix them under ultraviolet light conditions for 0.5 - 2 h. After the reaction is completed, evaporate the solvent. After uniformly mixing the product with the auxiliary agent, carry out kneading, and then carry out calendering and cooling after melt extrusion to obtain a sheet. The temperature of the melt extrusion is 240 - 260 °C.

Images