High-temperature-resistant and aging-resistant high-strength PET modified material and preparation method thereof

Abstract

The application provides a high-strength PET modified material resistant to high temperature and aging and a preparation method thereof, and relates to the technical field of PET modified materials.The high-strength PET modified material resistant to high temperature and aging is composed of PET resin, SEBS grafted glycidyl methacrylate, a composite nucleating agent, a compatilizer, a dispersing agent, a light stabilizer, a lubricant and the like.The application utilizes the synergistic effect among the raw materials, improves the heat resistance, aging resistance and mechanical strength of the PET material without affecting the transparency of the PET material, and has good industrial production prospect and high economic value.

Description

Technical Field

[0001] This invention relates to the field of PET modified materials technology, and in particular to a high-strength PET modified material that is resistant to high temperatures and aging, and its preparation method. Background Technology

[0002] In the home appliance industry, both domestically and internationally, GPPS materials are widely used in the manufacture of transparent refrigerator products. However, GPPS transparent products suffer from problems such as easy cracking and low cost-effectiveness. To address this shortcoming, a transparent PET material has been successfully developed to replace GPPS in refrigerator transparent products, representing a historic breakthrough in the refrigerator injection molding industry.

[0003] PET is the most important type of thermoplastic polyester, possessing many advantages, such as good mechanical properties, high impact strength, good toughness, oil and acid / alkali resistance, excellent solvent resistance and barrier properties; high transparency, blocking ultraviolet rays, and good gloss; non-toxic, odorless, and with good hygiene and safety. It is mainly used in the production of plastic packaging materials for daily life, disposable beverage materials, cosmetic bottles, and mineral water bottles. However, compared to conventional transparent materials such as PMMA (polymethyl methacrylate) and PC (polycarbonate), PET material has insufficient crystallinity, resulting in poorer heat resistance, a lower heat distortion temperature, and a long-term service temperature below 50℃. Furthermore, transparent PET products are highly susceptible to deformation during shipping due to high temperature and humidity.

[0004] Existing technologies for improving the heat resistance of PET include increasing its crystallinity. However, excessively high crystallinity reduces the transparency of PET products, making them unsuitable for transparent applications. Another method is to blend PET with heat-resistant and transparent materials such as PC or PCTG, but this suffers from poor compatibility, reduced mechanical properties, compromised transparency, and high costs. Furthermore, modern refrigerators and other household appliances incorporate UV sterilization or decorative modules, which can contribute to the aging and discoloration of transparent PET products. Therefore, improving the heat resistance, UV aging resistance, and mechanical strength of PET without compromising its transparency is a key technical challenge that needs to be addressed. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a high-strength PET modified material with high temperature and aging resistance, and its preparation method. Through the synergistic effect between different raw materials, the heat resistance, UV aging resistance, and mechanical strength of the PET material are improved without affecting its transparency.

[0006] The high-strength PET modified material with high temperature resistance and aging resistance described in this invention comprises the following raw materials in parts by weight:

[0007] 80-90 parts PET resin, 10-20 parts SEBS grafted glycidyl methacrylate (GMA), 0.5-2 parts composite nucleating agent, 2-3 parts compatibilizer, 0.5-1 part dispersant, 1-2 parts light stabilizer, and 0.5-1 part lubricant.

[0008] Furthermore, the lubricant is one or both of pentaerythritol stearate and ethylene bis-stearamide.

[0009] Furthermore, the compatibilizer is maleic anhydride-grafted POE.

[0010] Furthermore, the dispersant is one or more of stearamide, calcium stearate, and tristearate glycerol. The dispersant can reduce the mutual aggregation between nucleating agents, making the reaction of the dispersant in the raw material more complete, thereby improving the crystallization rate of the PET polyester composite material.

[0011] Furthermore, the light stabilizer is one or more of TiO2, ZnO, and hindered amine light stabilizers.

[0012] Furthermore, the particle size of the TiO2 and ZnO is between 1-100 nm.

[0013] Furthermore, the light stabilizer is composed of TiO2, ZnO, and hindered amine light stabilizer in a weight ratio of 5:1:1.

[0014] Furthermore, the composite nucleating agent is prepared by compounding nano-silicon carbide and organosilicon phosphate in a weight ratio of 2:1.

[0015] The presence of hydroxyl groups in the organosilicon phosphate molecule allows it to react with the terminal hydroxyl groups of PET, thereby increasing the material's relative viscosity, which in turn increases its relative molecular mass and heat resistance. The Si-O-Si groups contribute to this heat resistance. The addition of nano-sized silicon carbide / organosilicon phosphate particles acts as a heterogeneous nucleation agent, altering the nucleation mechanism of PET and increasing its crystallization rate. This results in nanoscale dispersed crystals that are on par with the wavelength of light, without affecting light transmission. This significantly improves the material's transparency, while also enhancing its thermal stability and mechanical properties.

[0016] Furthermore, the nano-silicon carbide is silane coupling agent modified nano-silicon carbide, and the preparation method of the silane coupling agent modified nano-silicon carbide is as follows:

[0017] Nano-silicon carbide powder was dried at 100℃ for 12 hours in a vacuum drying oven. The dried silicon carbide was then ultrasonically dispersed in xylene for 30 minutes. The silane coupling agent was diluted with xylene to a concentration of 20% under ultrasonic conditions and reacted under a nitrogen atmosphere for 4-6 hours. After the reaction was completed, the mixture was centrifuged and dried in an oven at 70℃ to obtain silane coupling agent modified nano-silicon carbide. The silane coupling agent is chemically bonded to the surface of the nano-silicon carbide and forms an organic coating layer, which effectively improves its agglomeration phenomenon.

[0018] Furthermore, the amount of the silane coupling agent added is 2.5wt%-4wt% of the total weight of the nano-silicon carbide.

[0019] Surface modification of nano-silicon carbide and strict control of the preparation process can improve the compatibility between nano-silicon carbide and resin and enhance the strength and heat resistance of the resin.

[0020] This invention also provides a method for preparing the high-strength PET modified material with high temperature resistance and aging resistance, comprising the following steps:

[0021] S1. Weigh the raw materials according to the proportion and mix them evenly. Stir at 400-600 r / min for 5-60 min to obtain the mixture.

[0022] S2. The mixture is added to a twin-screw extruder for melt blending, extrusion, cooling, and granulation to obtain a high heat-resistant and high weather-resistant PET material.

[0023] Furthermore, the temperature of the twin-screw extruder is controlled by zones: Zone 1 230℃-250℃, Zone 2 250℃-260℃, Zone 3 260℃-270℃, Zone 4 270℃-280℃, Zone 5 280℃-300℃, and Zone 6 280℃-300℃.

[0024] Furthermore, the die head temperature of the twin-screw extruder is 280℃-300℃, and the screw speed is 180-300 r / min.

[0025] The composite light stabilizer and composite nucleating agent of this invention exhibit excellent synergistic effects, which can improve the crystallization rate and crystallinity of PET materials, enhance their resistance to UV aging, and inhibit the growth of PET spherulites due to the abundance of nucleation sites. This increases the transparency of PET while simultaneously improving the matrix's resistance to heat deformation under load. Furthermore, the nanocomposite nucleating agent of this invention exhibits excellent synergistic effects with GMA, improving the toughness and impact resistance of PET materials.

[0026] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0027] (1) The PET material of the present invention has good toughness and low cracking rate, and can maintain good mechanical strength while reducing product thickness to reduce product manufacturing cost;

[0028] (2) This invention improves the tensile strength, elongation at break, flexural strength, flexural modulus, notched impact strength and flexibility of PET material while ensuring its transparency. Detailed Implementation

[0029] The technical solution provided by the present invention will be further described below with reference to the embodiments.

[0030] The preparation method of silane coupling agent modified nano-silicon carbide used in the embodiments and comparative examples of the present invention is as follows: Nano-silicon carbide powder is dried in a vacuum drying oven at 100°C for 12 hours. The dried silicon carbide is then added to xylene and ultrasonically dispersed for 30 minutes. Under ultrasonic conditions, the silane coupling agent is diluted with xylene to a concentration of 20%, and then reacted under a nitrogen atmosphere for 6 hours. After the reaction is completed, the mixture is centrifuged and dried in an oven at 70°C to obtain silane coupling agent modified nano-silicon carbide, wherein the amount of silane coupling agent added is 3 wt% of the total weight of nano-silicon carbide.

[0031] Example 1

[0032] A high-strength PET modified material with high temperature resistance and aging resistance, composed of the following raw materials in parts by weight:

[0033] 80 parts PET resin, 10 parts SEBS grafted glycidyl methacrylate (GMA), 0.5 parts composite nucleating agent, 2 parts maleic anhydride grafted POE, 0.5 parts calcium stearate, 1 part light stabilizer, and 0.5 parts ethylene bis-stearamide.

[0034] The average particle size of the TiO2 is 65 nm, and the average particle size of the ZnO is 50 nm; the light stabilizer is composed of TiO2, ZnO, and hindered amine light stabilizer in a weight ratio of 5:1:1.

[0035] Furthermore, the composite nucleating agent is prepared by compounding silane coupling agent modified nano-silicon carbide and organosilicon phosphate in a weight ratio of 2:1.

[0036] The preparation method of the high-strength PET modified material with high temperature resistance and aging resistance is as follows:

[0037] S1. Weigh the raw materials according to the proportion and mix them evenly. Stir at 550 r / min for 30 min to obtain the mixture.

[0038] S2. The mixture is added to a twin-screw extruder for melt blending, extrusion, cooling, and granulation to obtain a high heat-resistant and high weather-resistant PET material;

[0039] The temperature of the twin-screw extruder is controlled by zones: zone 1 230℃, zone 2 250℃, zone 3 270℃, zone 4 280℃, zone 5 280℃-300℃, and zone 6 300℃; the die temperature of the twin-screw extruder is 300℃, and the screw speed is 200 r / min.

[0040] Example 2

[0041] A high-strength PET modified material with high temperature resistance and aging resistance, composed of the following raw materials in parts by weight:

[0042] 90 parts of PET resin, 20 parts of SEBS-grafted glycidyl methacrylate (GMA), 2 parts of composite nucleating agent, 3 parts of maleic anhydride-grafted POE, 1 part of tristearate glycerol, 2 parts of light stabilizer, 1 part of pentaerythritol stearate lubricant, and the rest are the same as in Example 1.

[0043] Example 3

[0044] A high-strength PET modified material with high temperature resistance and aging resistance, composed of the following raw materials in parts by weight:

[0045] 80 parts PET resin, 20 parts SEBS grafted glycidyl methacrylate (GMA), 1.5 parts composite nucleating agent, 2 parts maleic anhydride grafted POE, 0.7 parts calcium stearate, 1.5 parts light stabilizer, 0.6 parts ethylene bis-stearamide, and the rest are the same as in Example 1.

[0046] Example 4

[0047] A high-strength PET modified material with high temperature resistance and aging resistance, composed of the following raw materials in parts by weight:

[0048] 85 parts of PET resin, 15 parts of SEBS-grafted glycidyl methacrylate (GMA), 0.5 parts of composite nucleating agent, 2.5 parts of compatibilizer, 0.6 parts of tristearate glycerol, 2 parts of light stabilizer, 0.5 parts of ethylene bis-stearamide, and the rest are the same as in Example 1.

[0049] The product in Example 2 showed the best performance after testing. The testing methods and results are as follows:

[0050]

[0051]

[0052] Comparative Example 1

[0053] Same as Example 2, except that the silane coupling agent modified nano-silicon carbide is replaced with an equal amount of nano-silicon carbide.

[0054] The performance test results of Comparative Example 1 are as follows:

[0055] Elongation at break (%) ASTM D638 163.85 Bending strength (MPa) ASTM D790 78.11 Flexural modulus (MPa) ASTM D790 2487.96 Heat distortion temperature (°C) ASTM D648 72.1℃ UV resistance ASTM D4329A △Eab=3.7 Light transmittance (%) ASTM D1003 87

[0056] Comparative Example 2

[0057] Same as Example 2, except that the light stabilizer is only a hindered amine light stabilizer.

[0058] The performance test results of Comparative Example 2 are as follows:

[0059] Elongation at break (%) ASTM D638 181.47 Bending strength (MPa) ASTM D790 77.74 Flexural modulus (MPa) ASTM D790 2500.03 Heat distortion temperature (°C) ASTM D648 72.6℃ UV resistance ASTM D4329A △Eab=4.8 Light transmittance (%) ASTM D1003 90

[0060] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-temperature and aging-resistant high-strength PET modified material, characterized in that, The composition, by weight, is as follows: 90 parts PET resin, 20 parts SEBS grafted glycidyl methacrylate, 2 parts composite nucleating agent, 3 parts maleic anhydride grafted POE, 1 part tristearate glycerol, 2 parts light stabilizer, and 1 part pentaerythritol stearate lubricant. The light stabilizer is composed of TiO2, ZnO, and hindered amine light stabilizer in a weight ratio of 5:1:1; the average particle size of the TiO2 is 65 nm and the average particle size of the ZnO is 50 nm. The composite nucleating agent is prepared by compounding silane coupling agent modified nano-silicon carbide and organosilicon phosphate in a weight ratio of 2:

1. The preparation method of the silane coupling agent modified nano silicon carbide is as follows: the nano silicon carbide powder is dried in a vacuum drying oven at 100°C for 12 h, the dried silicon carbide is added to xylene and ultrasonically dispersed for 30 min, and then diluted with xylene to a 20% concentration of silane coupling agent under ultrasonic conditions. After the reaction is completed, the mixture is centrifuged and dried in an oven at 70°C to obtain silane coupling agent modified nano silicon carbide, wherein the amount of silane coupling agent added is 3 wt% of the total weight of nano silicon carbide. The preparation method of the high-strength PET modified material with high temperature resistance and aging resistance is as follows: S1. Weigh the raw materials according to the proportion and mix them evenly. Stir at 550 r / min for 30 min to obtain the mixture. S2. The mixture is added to a twin-screw extruder for melt blending, extrusion, cooling, and granulation to obtain a high heat-resistant and high weather-resistant PET material; The temperature of the twin-screw extruder is controlled by zones: zone 1 230℃, zone 2 250℃, zone 3 270℃, zone 4 280℃, zone 5 280℃-300℃, and zone 6 300℃; the die temperature of the twin-screw extruder is 300℃, and the screw speed is 200 r / min.

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