Damp-heat-resistant ultraviolet barrier polyester master batch and preparation method thereof

Abstract

The invention belongs to the technical field of polyester master batches, and particularly relates to a damp-heat-resistant ultraviolet barrier polyester master batch and a preparation method thereof. The invention discloses an anti-ultraviolet polyethylene glycol terephthalate composite material, which is prepared from the following raw materials in parts by weight: 85 to 90 parts of polyethylene glycol terephthalate, 10 to 15 parts of anti-ultraviolet agent, 3 to 5 parts of epoxy-terminated polyether and 1 to 3 parts of lubricant, wherein the anti-ultraviolet agent is a modified intermediate obtained by modifying a nano light screening agent by a carboxylic ester coupling agent according to a mass ratio of (3 to 5): 100; the modified intermediate and a hydroxybenzophenone derivative are subjected to a grafting reaction according to the mass ratio of 100: (5-8); the nano light screening agent is selected from one or a combination of two or more of nano zinc oxide, nano titanium dioxide, nano cerium oxide, nano tin antimony oxide and nano carbon black. The dispersion effect of the anti-ultraviolet agent in the master batch is improved, and the ultraviolet barrier and the light transmittance are improved; meanwhile, the anti-ultraviolet agent is subjected to ester exchange with PET in the screw extrusion process, so that the interaction with PET is enhanced, migration in a humid and hot environment is avoided, and the ultraviolet shielding performance is lasting and stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyester masterbatch, and particularly relates to a polyester masterbatch with moisture and heat resistance and ultraviolet barrier and a preparation method thereof. Background Art

[0002] The main purpose of food packaging is to protect food from light, moisture, oxygen and microbial contamination during storage, transportation and shelf life, so as to avoid adverse changes in the smell, color and quality of food. These changes not only shorten the shelf life of food, but may also pose a hazard to the health of consumers. Among them, the influence of light, especially ultraviolet (UV) light, is particularly significant. Ultraviolet light can stimulate photosensitive substances in food to undergo chemical reactions, resulting in color fading, odor change, and even the generation of harmful substances in food. In addition, the penetration of moisture and oxygen will accelerate the oxidation and deterioration of food, while microbial contamination may cause food spoilage, further affecting food safety and quality.

[0003] In order to extend the shelf life of food, modern food packaging materials need to have excellent barrier properties and be able to effectively block the intrusion of ultraviolet light, oxygen, water vapor and microorganisms. At the same time, with the increasing requirements of consumers for packaging transparency, cleanliness, safety and environmental protection, food packaging materials also need to meet the characteristics of transparency, non-toxic and odorless, easy to process, impact-resistant, recyclable, etc. Polyester materials, especially polyethylene terephthalate (PET), have been widely used in the field of food packaging due to their high transparency, excellent mechanical properties, good chemical stability, easy processing and recyclability. For example, a high-strength and high-barrier heat-sealable BOPET film and a preparation method thereof disclosed in Patent CN118181921A have a double-layer composite film structure of a surface layer and a base layer. By using the method of physical blending and extrusion and the action of chemical bond energy, the composite BOPET film has a stable structure and high strength; the functional PET masterbatch used in the surface layer is beneficial to improving the overall mechanical properties and ultraviolet barrier properties, reducing the possibility of damage to the base layer material caused by ultraviolet light aging; the base layer material can ensure the heat-sealability of the whole film, and the base layer also improves the barrier properties and mechanical properties of the BOPET film. The addition of graphene oxide to the surface layer and the base layer improves the compatibility and stability of the surface layer and the base layer. The BOPET ultraviolet shielding masterbatch and its manufacturing method disclosed in Patent CN107418159A include the following raw materials in parts by weight: 70-90 parts of polyethylene terephthalate, 1-5 parts of dispersant, 5-20 parts of colorant, 10-20 parts of nano-scale ultraviolet absorber and 5-10 parts of meta-aramid fiber.

[0004] The above technologies all prepare masterbatches by co-extruding inorganic ultraviolet shielding agents and other substances with substrate resins, thereby endowing products with excellent ultraviolet blocking performance. However, in actual applications, it is difficult to avoid humid and hot environments. Humidity and heat increase the mobility of inorganic particles, causing them to gradually deviate from their original stable distribution positions in the resin matrix, significantly deteriorating the ultraviolet blocking effect of the material and failing to maintain the initial high ultraviolet blocking state.

[0005] Therefore, it is necessary to develop a polyester masterbatch that can endow polyester materials with high ultraviolet blocking and high light transmittance to meet the requirements of food packaging for long-term freshness preservation, high quality, and clear display. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides an ultraviolet blocking polyester masterbatch and its preparation method. The ultraviolet absorber in the masterbatch raw materials is a nano-photo-shielding agent grafted with a hydroxybenzophenone derivative through an ester group on its surface. This graft modification of the nano-photo-shielding agent can not only improve the dispersion effect of the ultraviolet absorber in the masterbatch, improve ultraviolet blocking and light transmittance, but also undergo transesterification with PET during the extrusion process to enhance the interaction with PET, avoid migration under humid and hot environments, and make the ultraviolet shielding performance last stably. To achieve the above object, the present invention adopts the following technical solutions: A humidity and heat resistant ultraviolet blocking polyester masterbatch, comprising the following raw materials in parts by weight: 85-90 parts of polyethylene terephthalate, 10-15 parts of ultraviolet absorber, 3-5 parts of terminal epoxy polyether, 1-3 parts of lubricant. The ultraviolet absorber is obtained by modifying a nano-photo-shielding agent with a carboxylic acid ester coupling agent in a mass ratio of 3-5:100 to obtain a modified intermediate, and then grafting the obtained modified intermediate with a hydroxybenzophenone derivative in a mass ratio of 100:5-8; the nano-photo-shielding agent is selected from one or a combination of two or more of nano-zinc oxide, nano-titanium dioxide, nano-cerium oxide, nano-tin antimony oxide, and nano-carbon black.

[0007] The hydroxybenzophenone derivative is selected from one or a combination of two or more of 3'-(1-hydroxyethyl) benzophenone and 4-(hydroxymethyl) phenyl ketone.

[0008] The carboxylic acid ester coupling agent is selected from one or a combination of two or more of ethyl 3-triethoxysilylpropionate, methyl 4-triethoxysilylbutyrate, and diethyl 2-(3-(triethoxymethylsilyl)propyl)malonate.

[0009] The average particle size of the nano-photo-shielding agent is 20-50 nm.

[0010] The ultraviolet absorber is prepared by a method including the following steps: 1) Prepare an alcoholysis solution of the carboxylic acid ester coupling agent, disperse the nano-photo-shielding agent into the alcoholysis solution, and react to obtain a modified intermediate; 2) Disperse the modified intermediate in an organic solvent, add the hydroxybenzophenone derivative and the catalyst, mix well, heat up to the reflux state for reaction to obtain the anti-ultraviolet agent.

[0011] In step 1), the alcoholysis solution is prepared by mixing ethanol and water in a mass ratio of 90 - 95:5 - 10 to form an alcohol / water solution, adjusting the pH to 4.5 - 5.5, adding the carboxylic acid ester coupling agent, mixing well and standing for 5 - 10 min to obtain the alcoholysis solution. The concentration of the carboxylic acid ester coupling agent in the alcoholysis solution is 1 - 2 wt%. The dispersion is carried out by ultrasonic dispersion for 10 - 30 min under the conditions of a power of 200 - 300 W and a frequency of 50 - 80 kHz. The reaction is carried out under the conditions of a stirring speed of 500 - 800 r / min and a temperature of 40 - 60 °C for 0.5 - 1 h. After the reaction, it also successively includes centrifugation, washing, and drying. The washing is carried out by washing with water 1 - 3 times. The drying is carried out at 100 - 120 °C for 5 - 15 min.

[0012] In step 2), the dispersion is carried out by ultrasonic dispersion for 10 - 30 min under the conditions of a power of 200 - 300 W and a frequency of 50 - 80 kHz. The organic solvent is selected from one or a combination of two or more of chloroform, ethyl acetate, benzene, toluene, xylene, and dichloromethane, and is preferably a mixed solvent of ethyl acetate and toluene in a volume ratio of 3 - 5:1. The catalyst is selected from one of tetrabutyl titanate, p-toluenesulfonic acid, and sodium formate. The dosage of the catalyst is 1 - 1.5 wt% of the hydroxybenzophenone derivative. The reaction time is 10 - 18 h. By-products are distilled out during the reaction. After the reaction, it also includes cooling to room temperature, centrifugation, washing, and drying. The washing is carried out by alternately washing with water and ethanol 1 - 3 times. The drying is carried out at 100 - 120 °C for 5 - 15 min.

[0013] During the screw extrusion process, under the action of shear and heat, an ester exchange reaction occurs between PET and the anti-ultraviolet agent. Although it is beneficial to improve the moisture and heat resistance of the masterbatch or the composite material prepared using the masterbatch, at the same time, a small amount of low-molecular-weight polyester will be generated due to ester exchange, resulting in an increase in the free volume of the masterbatch or the composite material prepared using the masterbatch and an increase in the water vapor transmission rate. An appropriate amount of terminal epoxy group polyether reacts with the terminal carboxyl or hydroxyl group of PET through its active epoxy group, which can not only reduce the low-molecular-weight polyester but also fill the free volume voids through the flexible polyethylene glycol chain segment, effectively controlling the increase in the water vapor transmission rate while maintaining the durability of ultraviolet barrier.

[0014] The number average molecular weight of the terminal epoxy group polyether is 380 - 500 g / mol, and it is specifically selected from one or a combination of two of polyethylene glycol diglycidyl ether and poly(propylene glycol) diglycidyl ether.

[0015] The intrinsic viscosity of the polyethylene terephthalate is 0.75 - 0.82 dL / g.

[0016] The lubricant is selected from one or a combination of two or more of silicone powder, bis-ethylene stearamide, zinc stearate, calcium stearate, polyethylene wax, and erucamide.

[0017] The present invention also provides a method for preparing the above-mentioned polyester masterbatch with moisture and heat resistance and ultraviolet barrier properties, which includes the following steps: Mix polyethylene terephthalate, an ultraviolet absorber, an epoxy-terminated polyether, and a lubricant, and then extrude and pelletize to obtain the ultraviolet barrier polyester masterbatch.

[0018] The pelletizing process parameters are as follows: carried out in a twin-screw extruder, the screw speed is 210 - 240 r / min, the temperature of the first zone of the twin-screw extruder is 190°C - 200°C, the temperature of the second zone is 200°C - 210°C, the temperature of the third zone is 225°C - 235°C, the temperature of the fourth zone is 255°C - 260°C, the temperature of the fifth zone is 260°C - 265°C, the temperature of the sixth zone is 265°C - 270°C, and the head temperature is 255 - 260°C.

[0019] The present invention also provides a PET bottle, the raw materials of which include the above-mentioned polyester masterbatch with moisture and heat resistance and ultraviolet barrier properties; the polyester masterbatch with moisture and heat resistance and ultraviolet barrier properties accounts for 3 - 5 wt% of the raw materials of the PET bottle.

[0020] The PET bottle is obtained by blending the raw materials of the PET bottle and injection molding into a preform, and then performing longitudinal stretching while performing transverse stretching and blowing.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the ultraviolet absorber in the masterbatch raw materials of the present invention is a nano-photo-shielding agent with a hydroxybenzophenone derivative grafted on the surface through an ester group. The modification of the nano-photo-shielding agent can improve the dispersion effect of the ultraviolet absorber in the masterbatch, and improve the ultraviolet barrier and light transmittance; at the same time, the ultraviolet absorber undergoes transesterification with PET during the screw extrusion process to enhance the interaction with PET, avoiding migration in a humid and hot environment, and making the ultraviolet shielding performance persistent and stable.

[0022] Second, the present invention utilizes the reaction of the active epoxy groups of the epoxy-terminated polyether with the terminal carboxyl or hydroxyl groups of PET to reduce the low-molecular-weight polyester generated by the transesterification of the ultraviolet absorber and PET. At the same time, the free volume voids are filled by the flexible polyol chain segments, overcoming the problem of high water vapor transmission rate caused by the low-molecular-weight polyester while maintaining the durability of the ultraviolet barrier. Detailed Embodiments

[0023] The following further illustrates the present invention with specific examples, but is not limited to the content in the specification. Unless otherwise specified, the "parts" in the embodiments of the present invention are all parts by weight. The reagents used are all commercially available reagents in the art.

[0024] Polypropylene glycol diglycidyl ether Mn-380, number average molecular weight 380, product number 406732, purchased from Sigma-Aldrich.

[0025] Polyethylene glycol diglycidyl ether Mn-500, number average molecular weight 500, product number 475696, purchased from Sigma-Aldrich.

[0026] Rutile-type nano titanium dioxide with an average particle size of 20 nm, grade TTP-R60S, purchased from Jiangsu Tianxing New Materials Co., Ltd.

[0027] 4-(Hydroxymethyl)benzophenone was purchased from Anyoji Chemical, product number JX450107.

[0028] 3'-(1-Hydroxyethyl)benzophenone (CAS No. 67173-18-6) was purchased from Shenzhen Hengfeng Wanda Medical Technology Co., Ltd.

[0029] Polyethylene terephthalate, intrinsic viscosity 0.8 dL / g, purchased from Shanghai Macklin Biochemical Co., Ltd.

[0030] Example 1 1) Ethanol and water were formulated into an alcohol / water solution at a mass ratio of 90:10, the pH was adjusted to 5.5, and ethyl 3-triethoxysilylpropionate was added and mixed well, then left standing for 10 min to obtain an alcoholysis solution. The concentration of ethyl 3-triethoxysilylpropionate in the alcoholysis solution was 1 wt%. 100 kg of nano titanium dioxide TTP-R60S was ultrasonically dispersed into 500 kg of the alcoholysis solution under the conditions of a power of 200 W, a frequency of 50 kHz, and a time of 20 min. The reaction was carried out at a stirring speed of 800 r / min and a temperature of 60 °C for 0.5 h. After the reaction, centrifugation was carried out, the centrifuged solid was washed with water 3 times, and dried at 100 °C for 15 min to obtain a modified intermediate. 2) 10 kg of the modified intermediate was ultrasonically dispersed into 200 kg of a mixed solvent of ethyl acetate and toluene at a volume ratio of 5:1 under the conditions of a power of 200 W, a frequency of 50 kHz, and a time of 20 min. 0.8 kg of 4-(hydroxymethyl)benzophenone and 8 g of p-toluenesulfonic acid were added and mixed well, then the temperature was raised to the reflux state for reaction, and at the same time the by-products were distilled out. After the reaction, it was cooled to room temperature, centrifuged, the centrifuged solid was washed alternately with ethanol and water 3 times, and dried at 100 °C for 15 min to obtain an anti-ultraviolet agent.

[0031] 3) 8.5 kg of polyethylene terephthalate, 1.5 kg of the anti-ultraviolet agent, 0.5 kg of polyethylene glycol diglycidyl ether (product number 475696), and 0.3 kg of zinc stearate were mixed well in a high-speed mixer and granulated to obtain a heat and humidity resistant ultraviolet barrier polyester masterbatch.

[0032] Among them, granulation is carried out in a twin-screw extruder: the screw speed is 210 r / min, the temperature of the first zone of the twin-screw extruder is 190 °C, the temperature of the second zone is 200 °C, the temperature of the third zone is 225 °C, the temperature of the fourth zone is 255 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, and the temperature of the die head is 260 °C.

[0033] 4) Weigh 94 kg of polyethylene terephthalate, 5 kg of ultraviolet barrier polyester masterbatch, and 1 part of bis(2-ethylhexyl) sebacate and mix them evenly in a high-speed mixer to obtain the blended PET bottle raw material. Inject it into preforms using an injection molding machine, then perform longitudinal stretching and at the same time perform transverse stretching using a stretch blow molding machine, and finally blow it up with compressed air to obtain PET bottles.

[0034] Example 2 The rest is the same as in Example 1, except that in step 2), the amount of 4-(hydroxymethyl)benzophenone is 0.5 kg, and the amount of the catalyst p-toluenesulfonic acid is 5 g.

[0035] Example 3 The rest is the same as in Example 1, except that in step 4), the amount of the ultraviolet barrier polyester masterbatch is 3 kg, and the amount of polyethylene terephthalate is 96 kg.

[0036] Example 4 The rest is the same as in Example 1, except that in step 3), the amount of the ultraviolet absorber is 1 kg.

[0037] Example 5 The rest is the same as in Example 1, except that in step 3), the amount of polyethylene glycol diglycidyl ether is 0.3 kg.

[0038] Example 6 The rest is the same as in Example 1, except that in step 3), an equal mass of polypropylene glycol diglycidyl ether (product number 406732) is used to replace polyethylene glycol diglycidyl ether (product number 475696).

[0039] Example 7 The rest is the same as in Example 1, except that in step 2), an equal mass of 3'-(1-hydroxyethyl)benzophenone is used to replace 4-(hydroxymethyl)benzophenone.

[0040] Example 8 1) Prepare an alcohol / water solution by mixing ethanol and water at a mass ratio of 90:10, adjust the pH to 5.5, add ethyl 3-triethoxysilylpropionate and mix well, then let it stand for 10 min to obtain an alcoholysis solution with a concentration of 1 wt% of ethyl 3-triethoxysilylpropionate. Ultrasonically disperse 100 kg of nano-titanium dioxide TTP-R60S into 300 kg of the alcoholysis solution under the conditions of a power of 200 W, a frequency of 50 kHz, and a time of 20 min. React at a stirring speed of 800 r / min and a temperature of 60 °C for 0.5 h. After the reaction, centrifuge, wash the centrifuged solid with water 3 times, and dry at 100 °C for 15 min to obtain a modified intermediate.

[0041] 2) Ultrasonically disperse 10 kg of the modified intermediate into 200 kg of a mixed solvent of ethyl acetate and toluene with a volume ratio of 5:1 under the conditions of a power of 200 W, a frequency of 50 kHz, and a time of 20 min. Add 0.8 kg of 4-(hydroxymethyl)benzophenone and 8 g of p-toluenesulfonic acid and mix well. Heat up to the reflux state for reaction while distilling out the by-products. After the reaction, cool to room temperature, centrifuge, wash the centrifuged solid alternately with ethanol and water 3 times, and dry at 100 °C for 15 min to obtain an anti-ultraviolet agent.

[0042] 3) Mix 9 kg of polyethylene terephthalate, 1.5 kg of the anti-ultraviolet agent, 0.3 kg of polyethylene glycol diglycidyl ether (product number 475696), and 0.3 kg of zinc stearate in a high-speed mixer, and granulate to obtain a heat and humidity resistant ultraviolet barrier polyester masterbatch.

[0043] The granulation is carried out in a twin-screw extruder: the screw speed is 210 r / min, the temperature of the first zone of the twin-screw extruder is 190 °C, the second zone is 200 °C, the third zone is 225 °C, the fourth zone is 255 °C, the fifth zone is 260 °C, the sixth zone is 265 °C, and the head temperature is 260 °C.

[0044] 4) Weigh 96 kg of polyethylene terephthalate, 3 kg of the ultraviolet barrier polyester masterbatch, and 1 part of bis-ethylene stearamide and mix them evenly in a high-speed mixer to obtain a blended PET bottle raw material. Inject it into a preform using an injection molding machine, and then perform longitudinal and transverse stretching simultaneously using a stretch blow molding machine, and finally blow it up with compressed air to obtain a PET bottle.

[0045] Comparative Example 1 1) Mix 8.5 kg of polyethylene terephthalate, 1.5 kg of a blend of nano-titanium dioxide TTP-R60S and 4-(hydroxymethyl)benzophenone at a mass ratio of 100:8, 0.5 kg of polyethylene glycol diglycidyl ether (product number 475696), and 0.3 kg of zinc stearate in a high-speed mixer, and granulate to obtain a heat and humidity resistant ultraviolet barrier polyester masterbatch.

[0046] Among them, granulation is carried out in a twin-screw extruder: the screw speed is 210 r / min, the temperature of the first zone of the twin-screw extruder is 190 °C, the temperature of the second zone is 200 °C, the temperature of the third zone is 225 °C, the temperature of the fourth zone is 255 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, and the head temperature is 260 °C.

[0047] 2) Weigh 94 kg of polyethylene terephthalate, 5 kg of ultraviolet barrier polyester masterbatch, and 1 part of bis(ethylenediamine) stearamide, mix them evenly in a high-speed mixer to obtain the blended PET bottle raw material, inject it into a preform using an injection molding machine, then perform longitudinal stretching and transverse stretching simultaneously using a stretch blow molding machine, and finally blow it up with compressed air to obtain the PET bottle.

[0048] Comparative Example 2 The rest is the same as in Example 1, except that in step 3), polyethylene glycol diglycidyl ether is not added.

[0049] Comparative Example 3 The rest is the same as in Example 1, except that there is no step of grafting 4-(hydroxymethyl)benzophenone, that is, step 2). 1) Prepare an alcohol / water solution by mixing ethanol and water at a mass ratio of 90:10, adjust the pH to 5.5, add 1 wt% of ethyl 3-triethoxysilylpropionate to the alcohol / water solution, mix well and let it stand for 10 min. Ultrasonically disperse 100 kg of nano-titanium dioxide TTP-R60S into 500 kg of hydrolysis solution under the conditions of a power of 800 W, a frequency of 50 kHz, and a time of 20 min. React at a stirring speed of 800 r / min and a temperature of 60 °C for 0.5 h. After the reaction, centrifuge, wash the centrifuged solid with water 3 times, and dry it at 100 °C for 15 min to obtain modified titanium dioxide, that is, the ultraviolet absorber. 2) Mix 8.5 kg of polyethylene terephthalate, 1.5 kg of ultraviolet absorber, 0.5 kg of polyethylene glycol diglycidyl ether (product number 475696), and 0.3 kg of zinc stearate evenly in a high-speed mixer, and granulate to obtain the ultraviolet barrier polyester masterbatch.

[0050] Among them, granulation is carried out in a twin-screw extruder: the screw speed is 210 r / min, the temperature of the first zone of the twin-screw extruder is 190 °C, the temperature of the second zone is 200 °C, the temperature of the third zone is 225 °C, the temperature of the fourth zone is 255 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, and the head temperature is 260 °C.

[0051] 3) Weigh 94 kg of polyethylene terephthalate, 5 kg of ultraviolet barrier polyester masterbatch, and 1 part of bis(ethylenediamine) stearamide, mix them evenly in a high-speed mixer to obtain the blended PET bottle raw material, inject it into a preform using an injection molding machine, then perform longitudinal stretching and transverse stretching simultaneously using a stretch blow molding machine, and finally blow it up with compressed air to obtain the PET bottle.

[0052] UV / visible light transmittance: The average transmittance of UV and visible light was measured using a UV-8000 UV-visible photometer from Shanghai Yuanxi Instrument Co., Ltd. The UV spectrum was 200-380 nm, and the visible spectrum was 380-780 nm. The sample was prepared by injection molding the blended PET bottle raw material prepared in step 4) of the above embodiment and comparative example on an injection molding machine. The barrel temperature of the injection molding machine was 245°C, 250°C, 260°C, 265°C, 272°C, and 270°C. The sample size was 100 mm*20 mm*3 mm.

[0053] Humidity and heat aging: Maintain at 50℃ / 90% RH for 7 days, re-measure the above UV transmittance, and calculate the increase rate of UV transmittance.

[0054] Water vapor transmission rate: refer to the standard GB / T 26253-2010 Determination of water vapor transmission rate of plastic films and sheets, the sample is 0.3mm sheet.

[0055] Table 1 Performance test results .

[0056] It can be seen from Table 1 that when the dosage of the ultraviolet blocking masterbatch of the present invention is 5wt%, it can block more than 98.9% of ultraviolet rays, at this time, the visible light transmittance is more than 91%, and the water vapor transmittance is less than 1.5g / m 2 ·24h, the UV transmittance after wet heat aging is not significantly improved. From Examples 1 and 2 and Comparative Example 3, it can be seen that nano titanium dioxide and 4-(hydroxymethyl)phenyl ketone have a synergistic effect of reducing UV transmittance.

[0057] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A polyester masterbatch with moisture and heat resistance and ultraviolet barrier property, characterized in that, It comprises the following raw materials in parts by weight: 85 - 90 parts of polyethylene terephthalate, 10 - 15 parts of ultraviolet absorber, 3 - 5 parts of terminal epoxy polyether, 1 - 3 parts of lubricant. The ultraviolet absorber is obtained by modifying a nano light shielding agent with a carboxylate coupling agent in a mass ratio of 3 - 5:100 to obtain a modified intermediate, and then grafting and reacting the modified intermediate with a hydroxybenzophenone derivative in a mass ratio of 100:5 - 8; the nano light shielding agent is selected from one or more combinations of nano zinc oxide, nano titanium dioxide, nano cerium oxide, nano tin antimony oxide, nano carbon black.

2. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 1, characterized in that, The hydroxybenzophenone derivative is selected from one or more combinations of 3'-(1-hydroxyethyl) benzophenone and 4-(hydroxymethyl) phenyl ketone.

3. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 1, wherein The carboxylate coupling agent is selected from one or more combinations of ethyl 3-triethoxysilylpropionate, methyl 4-triethoxysilylbutyrate, and diethyl 2-(3-(triethoxymethylsilyl)propyl)malonate.

4. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 1, wherein The average particle size of the nano light shielding agent is 20 - 50 nm.

5. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 1, characterized in that, The ultraviolet absorber is prepared by a method comprising the following steps: 1) Prepare an alcoholysis solution of the carboxylate coupling agent, disperse the nano light shielding agent into the alcoholysis solution, and react to obtain a modified intermediate; 2) Disperse the modified intermediate into an organic solvent, add the hydroxybenzophenone derivative and a catalyst, mix well, heat up to the reflux state and react to obtain the ultraviolet absorber.

6. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 5, characterized in that, In step 1), the concentration of the carboxylate coupling agent in the alcoholysis solution is 1 - 2 wt%.

7. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 5, wherein In step 2), the catalyst is selected from one of tetrabutyl titanate, p-toluenesulfonic acid, and sodium formate; the dosage of the catalyst is 1 - 1.5 wt% of the hydroxybenzophenone derivative; the reaction time is 10 - 18 h.

8. The heat and humidity resistant and ultraviolet barrier polyester masterbatch according to claim 1, wherein The number average molecular weight of the terminal epoxy polyether is 380 - 500 g / mol, and it is selected from one or more combinations of polyethylene glycol diglycidyl ether and poly(propylene glycol) diglycidyl ether; the intrinsic viscosity of the polyethylene terephthalate is 0.75 - 0.82 dL / g.

9. The preparation method of the polyester masterbatch with moisture and heat resistance and ultraviolet barrier according to any one of claims 1-8, characterized in that, It comprises the following steps: Mix the polyethylene terephthalate, ultraviolet absorber, terminal epoxy polyether, and lubricant evenly, and extrude and pelletize to obtain an ultraviolet barrier polyester masterbatch.

10. A PET bottle, characterized in that, The raw materials include the heat and humidity resistant ultraviolet barrier masterbatch according to any one of claims 1 - 8; the heat and humidity resistant ultraviolet barrier masterbatch accounts for 3 - 5 wt% of the PET bottle raw materials.