Scratch-resistant PETG transparent shrink film for battery label and preparation method of scratch-resistant PETG transparent shrink film

Abstract

The invention belongs to the technical field of material preparation, and particularly relates to a scratch-resistant PETG transparent shrink film for a battery label and a preparation method of the scratch-resistant PETG transparent shrink film. The scratch-resistant PETG transparent shrink film is prepared from the following raw materials: PETG master batches and function enhancing factors, the function enhancing factor is prepared from the following raw materials: Al2O3 (aluminum oxide), SiO2 (silicon dioxide), gamma-methacryloxy propyl trimethoxy silane and poly (3-hydroxyalkanoate). Through a special production process, the prepared PETG transparent shrink film has excellent optical performance and mechanical performance, is resistant to scraping, moderate in shrinkage performance and free of residues after film tearing, it can be guaranteed that a battery label is tightly attached to the surface of a battery, the protection effect of the label is improved, and the service life of the label is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation, and particularly relates to a scratch-resistant PETG transparent shrink film for battery labels and a preparation method thereof. Background Art

[0002] In the current field of electronic device manufacturing, as a key power supply component, the performance and safety of batteries are of crucial importance. And the battery label, as an important part of the battery, not only undertakes functions such as identifying product information, specification parameters, usage precautions, etc., but also plays a key role in the appearance and protection of the battery. PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol ester), as a high-performance transparent plastic material, has been widely used in the packaging field due to its excellent optical properties, good mechanical properties, chemical stability and processing performance. The PETG film has high transparency, can clearly display the packaged items, and meets the requirements for product appearance display; its good flexibility and tensile strength make it not easy to break during the processing process and can adapt to different-shaped packaging requirements. In addition, the PETG material also has good chemical corrosion resistance and can resist the erosion of chemical substances inside the battery to a certain extent.

[0003] However, for the application scenario of battery labels, ordinary PETG films have some limitations. During the production, transportation and use of batteries, the labels are frequently subjected to external forces such as friction and scratching. The scratch resistance of ordinary PETG films is insufficient, and scratches are likely to appear, affecting the clarity and beauty of the labels. Furthermore, it may lead to the difficulty of identifying product information and reduce the overall quality image of the product. At the same time, in the battery usage environment, factors such as temperature changes may cause the shrinkage performance of the labels to be unstable, unable to closely fit the battery surface, and affecting the protection effect and overall appearance of the labels.

[0004] With the development of electronic products towards miniaturization and high performance, the requirements for the performance and reliability of batteries are increasing day by day, which also puts forward higher requirements for the film materials used for battery labels. The market urgently needs a material that not only has excellent scratch resistance and can maintain the integrity and clarity of the labels in various complex environments, but also can maintain the high transparency and good shrinkage performance of the PETG film to meet the continuous development needs of the battery industry.

[0005] Therefore, the research and development of a scratch-resistant PETG transparent shrink film for battery labels has important practical significance and broad market prospects. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention provides a scratch-resistant PETG transparent shrink film for battery labels and a preparation method thereof. Through a special production process, the prepared PETG transparent shrink film has excellent optical and mechanical properties, is scratch-resistant, has moderate shrinkage properties, and has no residue after tearing, which can ensure that the battery label fits tightly on the battery surface, improving the protection effect and service life of the label.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of the present invention provides a scratch-resistant PETG transparent shrink film for battery labels, comprising the following raw materials:

[0009] PETG masterbatch, functional enhancement factor; the raw materials of the functional enhancement factor include Al2O3, SiO2, γ-methacryloxypropyltrimethoxysilane, and poly-3-hydroxyalkanoate.

[0010] In some embodiments, the preparation method of the PETG masterbatch is as follows:

[0011] Take terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, polyester, and a catalyst and add them to a reaction kettle, stir evenly, under a nitrogen atmosphere, stir and heat up to start the esterification reaction; after the esterification reaction is completed, add a capping agent and mix evenly, then raise the temperature of the reaction kettle to the polycondensation temperature, and at the same time evacuate to start the polycondensation reaction, during which the temperature of the reaction kettle is controlled, and finally the PETG masterbatch is prepared.

[0012] In some embodiments, the molar ratio of terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol is 4:(2-3):(1-2); the polyester is bisphenol A polyterephthalate, and its dosage is 0.5-1.5 wt% of the total mass of terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol.

[0013] In some embodiments, the catalyst is one of germanium-based catalysts, titanium-based catalysts, and antimony-based catalysts.

[0014] In some embodiments, the capping agent is glycidyl versatate.

[0015] In some embodiments, the preparation steps of the functional enhancement factor are as follows:

[0016] Disperse Al2O3 and SiO2 nanoparticles in a solvent respectively, add γ-methacryloxypropyltrimethoxysilane thereto, stir and react for 2-4 h, then add a solution of poly-3-hydroxyalkanoate thereto, stir and react at room temperature, and remove the solvent to obtain the functional enhancement factor.

[0017] In some embodiments, the dosage ratio of Al2O3 to SiO2 is 1.5:(2 - 3).

[0018] In some embodiments, the γ-methacryloyloxypropyltrimethoxysilane is 2 - 5% of the total mass of Al2O3 and SiO2, and the dosage of the poly-3-hydroxyalkanoate is 10 - 20% of the total mass of Al2O3 and SiO2.

[0019] Preferably, the particle size of Al2O3 and SiO2 is less than 50 nm.

[0020] In some embodiments, the dosage of the function enhancement factor is 5 - 20 wt% of the PETG masterbatch.

[0021] The second aspect of the present invention provides a method for preparing the scratch-resistant PETG transparent shrink film for battery labels according to the above scheme, including the following preparation steps:

[0022] Mix the PETG masterbatch and the function enhancement factor evenly, and then extrude, cast, stretch, shape, draw, and wind up to prepare the scratch-resistant PETG transparent shrink film for battery labels.

[0023] The present invention first synthesizes a functional enhancement factor. γ-Methacryloxypropyltrimethoxysilane is added to a solvent in which nano-Al2O3 and SiO2 particles are dispersed. The trimethoxysilyl group undergoes a hydrolysis reaction in the solvent to generate silanol groups, which undergo a condensation reaction with the hydroxyl groups on the surface of the nano-particles to form chemical bonds, thereby chemically bonding γ-methacryloxypropyltrimethoxysilane to the surface of nano-Al2O3 and SiO2 particles. Then, poly-3-hydroxyalkanoate is added. The hydroxyl groups on it interact with the methacryloxy groups on the surface of the nano-particles through hydrogen bonds. At the same time, the van der Waals forces between molecules also prompt them to approach and combine with each other. This interaction enables poly-3-hydroxyalkanoate to tightly wrap around the surface of the modified nano-particles, further enhancing the binding force between them and forming a stable composite system, making the surface of the originally hydrophilic inorganic nano-particles have a certain lipophilicity, thereby improving the compatibility between the functional enhancement factor and the organic material. The functional enhancement factor in the PETG shrink film can enhance the mechanical properties and optical properties of the film: (1) Improve the tensile strength: The functional enhancement factor, as the reinforcing phase, can bear a part of the external force. When the PETG film is stretched, the enhancement factor can transfer the stress to the entire system through the interfacial interaction with the PETG matrix, thereby improving the tensile strength of the PETG film; (2) Improve the scratch resistance: The composite system formed by γ-methacryloxypropyltrimethoxysilane, nano-Al2O3, SiO2 particles and poly-3-hydroxyalkanoate plays a role similar to a "rigid skeleton" in the PETG film. When the film surface is scratched, these rigid nano-particles can resist the external force and reduce the generation of scratches on the film surface; (3) Improve the thermal stability: After the functional enhancement factor is added to the PETG film, it can inhibit the thermal movement of the PETG molecular chains at high temperatures, thereby increasing the heat distortion temperature of the PETG film. Poly-3-hydroxyalkanoate can also improve the thermal stability of the PETG film to a certain extent. By interacting with the nano-particles and the PETG matrix, a more stable heat conduction network is formed, enabling heat to be more evenly dispersed; (4) Optimize the optical properties: By controlling the particle size and dispersibility of the functional enhancement factor to make it evenly dispersed in the PETG film, the scattering and absorption of light can be reduced, and the high transparency of the PETG film can be maintained.

[0024] The present invention also synthesizes a PETG masterbatch. Terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol undergo an esterification reaction under the action of a catalyst. Additionally, a polyester (bisphenol A polyterephthalate) is added to play a role in regulating the polymerization chain structure and properties. It can interact with the polymer chains being formed and participate in the esterification reaction, promoting chain growth and the formation of branched structures. After the esterification reaction is completed, glycidyl versatate as a capping agent is added, which can effectively reduce the activity of the end groups of the PETG molecular chains and interact with the functional enhancement factor to improve the compatibility between the two, enabling the functional enhancement factor to be more uniformly dispersed in the PETG matrix. If there are many active groups at the ends of the PETG molecular chains, during subsequent processing and use, it is easy to react with external chemical substances, such as being eroded by acidic and alkaline substances. The addition of glycidyl versatate causes its epoxy group to react with the active groups at the chain ends of PETG, closing the chain ends, enhancing the chemical stability of the PETG molecules, and improving the processing performance.

[0025] The PETG masterbatch of the present invention, when used together with the functional enhancement factor, can significantly improve the comprehensive performance of the PETG shrink film. The PETG masterbatch itself has certain flexibility and tensile strength, but it may be insufficient in scratch resistance. The nanoparticles in the functional enhancement factor have high hardness and can enhance the rigidity and wear resistance of the film. When the functional enhancement factor is added, the nanoparticles are uniformly dispersed in the PETG matrix. When subjected to external scratching, these nanoparticles can effectively resist the scratching force and improve the scratch resistance of the film. At the same time, the nanoparticles can also act as physical crosslinking points to enhance the interaction between PETG molecular chains and improve the tensile strength and toughness of the film to a certain extent. In addition, the thermal stability of the PETG masterbatch may be limited in some high-temperature environments. The inorganic nanoparticles in the functional enhancement factor have high thermal conductivity and thermal stability. They can form heat conduction channels in the PETG film, making the heat more evenly distributed and improving the heat dissipation ability of the film. At the same time, at high temperatures, these nanoparticles can inhibit the excessive thermal movement of the PETG molecular chains and increase the heat distortion temperature of the film. The shrinkage performance of the PETG masterbatch may be affected by environmental factors such as temperature and humidity. The poly-3-hydroxyalkanoate in the functional enhancement factor can interact with the PETG matrix to regulate the shrinkage behavior of the PETG film. In different temperature environments, the functional enhancement factor can make the shrinkage of the PETG film more uniform and stable, ensuring that the battery label fits tightly on the battery surface and improving the protection effect and service life of the label.

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

[0027] 1. The present invention has developed a scratch-resistant PETG transparent shrink film for battery labels. Through formula optimization, the prepared PETG transparent shrink film has excellent optical and mechanical properties, is scratch-resistant, has moderate shrinkage performance, and has no residue after film tearing.

[0028] 2. The present invention adds γ-methacryloxypropyltrimethoxysilane to a solvent in which nano-Al2O3 and SiO2 particles are dispersed for reaction, and then adds poly-3-hydroxyalkanoate for modification to synthesize a functional enhancement factor, making the surface of the originally hydrophilic inorganic nanoparticles have a certain lipophilicity, thereby improving the compatibility between the functional enhancement factor and the PETG substrate.

[0029] 3. The present invention uses terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol to carry out an esterification reaction under the action of a catalyst, additionally adds poly(bisphenol A terephthalate) to adjust the polymerization chain structure and properties, and then adds a capping agent, glycidyl versatate, to prepare a PETG masterbatch with strong chemical stability and good processing performance, which is beneficial to improving the performance of the scratch-resistant PETG transparent shrink film. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a process flow chart for the preparation of the PETG transparent shrink film of the present invention;

[0031] Figure 2 is the PETG transparent shrink film prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0032] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention. It should be understood that the terms described in the present invention are only for describing specific implementation modes and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0033] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. Various improvements and changes can be made to the specific embodiments of the description of this invention without departing from the scope or spirit of this invention, which will be obvious to those skilled in the art. Other embodiments obtained from the description of this invention will be obvious to those skilled in the art. The description and examples of this application are merely exemplary.

[0034] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0035] It should be noted that operations such as "grinding", "centrifuging", "stirring", etc. described in this invention are conventional operations for those skilled in the art and can be selected according to actual operations.

[0036] The parts by mass described in the following examples can be grams, kilograms, tons or other mass units.

[0037] The catalyst used in this invention is tetra-isopropyl titanate; the capping agent used is glycidyl versatate; the poly-3-hydroxyalkanoate used is BP350-05, purchased from Beijing Bluepha Microbial Technology Co., Ltd.; the commercially available PETG masterbatch used is AN011 from SK of South Korea; the average particle sizes of the used Al2O3 and SiO2 are both 30 nm.

[0038] Preparation Example 1

[0039] The preparation method of the PETG masterbatch is as follows:

[0040] Take 0.4 mol of terephthalic acid, 0.25 mol of ethylene glycol, 0.15 mol of 1,4-cyclohexanedimethanol, 1.15 g of poly(bisphenol A terephthalate), and 0.1 g of catalyst and add them to a reaction kettle, stir evenly. Under a nitrogen atmosphere, at a stirring speed of 250 rpm, heat up to 250 °C and carry out an esterification reaction for 3 h; after the esterification reaction is completed, add 3 g of capping agent and mix evenly, then raise the temperature of the reaction kettle to the polycondensation temperature of 280 °C, at the same time evacuate and remove the excess ethylene glycol and water, and start the polycondensation reaction for 1 h. During this period, control the temperature of the reaction kettle to be stable at about 280 °C, and finally process to obtain the PETG masterbatch.

[0041] Preparation Example 2

[0042] The preparation method of the PETG masterbatch is substantially the same as that of Preparation Example 1, except that poly(bisphenol A terephthalate) is not added.

[0043] Preparation Example 3

[0044] The preparation method of the PETG masterbatch is substantially the same as that of Preparation Example 1, except that the end-capping agent is not added.

[0045] Preparation Example 4

[0046] The preparation method of the PETG masterbatch is substantially the same as that of Preparation Example 1, except that 0.3 mol of terephthalic acid is used.

[0047] Preparation Example 5

[0048] The preparation method of the PETG masterbatch is as follows:

[0049] Take 0.4 mol of terephthalic acid, 0.2 mol of ethylene glycol, 0.1 mol of 1,4-cyclohexanedimethanol, 0.55 g of bisphenol A polyterephthalate and 0.5 g of catalyst and add them to the reaction kettle, stir evenly, under a nitrogen atmosphere, at a stirring speed of 300 rpm, heat up to 240 °C, and carry out the esterification reaction for 3.5 h; after the esterification reaction is completed, add 2.5 g of end-capping agent and mix evenly, then raise the temperature of the reaction kettle to the polycondensation temperature of 270 °C, at the same time evacuate and remove the excess ethylene glycol and water, and start the polycondensation reaction for 1 h. During this period, control the temperature of the reaction kettle to be stable at about 270 °C, and finally process to obtain the PETG masterbatch.

[0050] Preparation Example 6

[0051] The preparation method of the PETG masterbatch is as follows:

[0052] Take 0.4 mol of terephthalic acid, 0.3 mol of ethylene glycol, 0.2 mol of 1,4-cyclohexanedimethanol, 1.8 g of bisphenol A polyterephthalate and 1.25 g of catalyst and add them to the reaction kettle, stir evenly, under a nitrogen atmosphere, at a stirring speed of 200 rpm, heat up to 260 °C, and carry out the esterification reaction for 2.5 h; after the esterification reaction is completed, add 3.5 g of end-capping agent and mix evenly, then raise the temperature of the reaction kettle to the polycondensation temperature of 290 °C, at the same time evacuate and remove the excess ethylene glycol and water, and start the polycondensation reaction for 45 min. During this period, control the temperature of the reaction kettle to be stable at about 290 °C, and finally process to obtain the PETG masterbatch.

[0053] Preparation Example 7

[0054] The preparation steps of the function enhancement factor are as follows:

[0055] Disperse 1.5 g of Al2O3 and 2.5 g of SiO2 nanoparticles in 80 mL of a 95 wt% ethanol aqueous solution. Add 0.16 g of γ-methacryloxypropyltrimethoxysilane thereto, and stir and react at 50 °C for 3 h. Then add 10 mL of a chloroform solution containing 0.6 g of poly-3-hydroxyalkanoate thereto, stir and react at room temperature for 2 h, and remove the solvent by rotary evaporation to obtain a functional enhancement factor.

[0056] Preparation Example 8

[0057] The preparation steps of the functional enhancement factor are substantially the same as those of Preparation Example 7, except that 0.5 g of Al2O3 is used.

[0058] Preparation Example 9

[0059] The preparation steps of the functional enhancement factor are as follows:

[0060] Disperse 1.5 g of Al2O3 and 2.5 g of SiO2 nanoparticles in 80 mL of a 95 wt% ethanol aqueous solution, stir at 50 °C for 3 h, then add 10 mL of a chloroform solution containing 0.6 g of poly-3-hydroxyalkanoate thereto, stir and react at room temperature for 2 h, and remove the solvent by rotary evaporation to obtain a functional enhancement factor.

[0061] Preparation Example 10

[0062] The preparation steps of the functional enhancement factor are as follows:

[0063] Disperse 1.5 g of Al2O3 and 2.5 g of SiO2 nanoparticles in 80 mL of a 95 wt% ethanol aqueous solution. Add 0.16 g of γ-methacryloxypropyltrimethoxysilane thereto, stir and react at 50 °C for 3 h, and remove the solvent by rotary evaporation to obtain a functional enhancement factor.

[0064] Example 1

[0065] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels includes the following preparation steps:

[0066] Melt 1 kg of PETG masterbatch and mix it evenly with 100 g of functional enhancement factor. Then, through extrusion (the temperature of the feeding section is 185 °C, the temperature of the compression section is 205 °C, the temperature of the metering section is 225 °C, the temperature of the die head is 235 °C, the screw speed is 100 revolutions / min, and the extrusion time is 45 min), casting (the temperature is 30 °C, the casting speed is 1 m / min, and the cooling time is 8 s), stretching (the temperature of the first longitudinal stretching is 100 °C, the stretching ratio is 2 times, and the stretching time is 8 s; the temperature of the second longitudinal stretching is 100 °C, the stretching ratio is 2 times, and the stretching time is 10 s), two times of shaping, traction (the speed is 1.35 m / min, and the traction force is 10 N), and winding, the scratch-resistant PETG transparent shrink film for battery labels is prepared.

[0067] The PETG masterbatch used is obtained from Preparation Example 1; the functional enhancement factor used is obtained from Preparation Example 7.

[0068] Example 2

[0069] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels includes the following preparation steps:

[0070] Melt 1 kg of PETG masterbatch and mix it evenly with 50 g of functional enhancement factor. Then, through extrusion (the temperature of the feeding section is 180 °C, the temperature of the compression section is 200 °C, the temperature of the metering section is 220 °C, the temperature of the die head is 230 °C, the screw speed is 50 revolutions / min, and the extrusion time is 60 min), casting (the temperature is 25 °C, the casting speed is 0.5 m / min, and the cooling time is 5 s), stretching (the temperature of the first longitudinal stretching is 110 °C, the stretching ratio is 3 times, and the stretching time is 5 s; the temperature of the second longitudinal stretching is 110 °C, the stretching ratio is 3 times, and the stretching time is 8 s), two times of shaping, traction (the speed is 1.2 m / min, and the traction force is 5 N), and winding, the scratch-resistant PETG transparent shrink film for battery labels is prepared.

[0071] The PETG masterbatch used is obtained from Preparation Example 5; the functional enhancement factor used is obtained from Preparation Example 7.

[0072] Example 3

[0073] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels includes the following preparation steps:

[0074] Melt 1 kg of PETG masterbatch and mix it evenly with 200 g of functional enhancement factor. Then, through extrusion (the temperature of the feeding section is 190 °C, the compression section is 210 °C, the metering section is 230 °C, the head temperature is 240 °C, the screw speed is 150 revolutions / min, and extrusion lasts for 30 min), casting (temperature 35 °C, casting speed 1.5 m / min, cooling time 10 s), stretching (the first longitudinal stretching temperature is 105 °C, the stretching ratio is 3 times, the stretching time is 10 s, the second longitudinal stretching temperature is 105 °C, the stretching ratio is 3 times, and the stretching time is 15 s), two times of shaping, traction (speed 1.5 m / min, traction force 15 N), and winding, the scratch-resistant PETG transparent shrink film for battery labels is prepared.

[0075] The PETG masterbatch used is obtained from Preparation Example 6; the functional enhancement factor used is obtained from Preparation Example 7.

[0076] Example 4

[0077] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels, the specific implementation manner is the same as that of Example 1, the difference is that the functional enhancement factor used is obtained from Preparation Example 8.

[0078] Example 5

[0079] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels, the specific implementation manner is the same as that of Example 1, the difference is that the functional enhancement factor used is obtained from Preparation Example 9.

[0080] Example 6

[0081] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels, the specific implementation manner is the same as that of Example 1, the difference is that the functional enhancement factor used is obtained from Preparation Example 10.

[0082] Comparative Example 1

[0083] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels, the specific implementation manner is the same as that of Example 1, the difference is that the functional enhancement factor is replaced by Al2O3 and SiO2 with equal mass and a mass ratio of 1.5:2.5.

[0084] Comparative Example 2

[0085] A preparation method of a scratch-resistant PETG transparent shrink film for battery labels, the specific implementation manner is the same as that of Example 1, the difference is that the PETG masterbatch used is a commercially available PETG masterbatch.

[0086] Performance Test

[0087] 1. The PETG masterbatches prepared in Preparation Examples 1-6 were injection-molded into dumbbell-shaped specimens with dimensions of 2.5 mm * 10 mm * 105 mm using a micro-injection molding machine. The tensile properties of each specimen were tested using a universal material tensile testing machine at a tensile rate of 10 mm / min, and the tensile strength and elongation at break of the specimens were recorded. The specific test data are shown in Table 1.

[0088] Table 1

[0089] Number Tensile strength / MPa Elongation at break / % Preparation Example 1 88 188 Preparation Example 2 77 173 Preparation Example 3 80 178 Preparation Example 4 74 171 Preparation Example 5 86 185 Preparation Example 6 87 187

[0090] As can be seen from Table 1, the PETG masterbatches prepared in Preparation Examples 1, 5, and 6 have excellent mechanical properties, with relatively good tensile strength and elongation at break. Compared with Preparation Example 1, the raw materials in the preparation process of the PETG masterbatches in Preparation Examples 2-4 changed, significantly affecting the elongation at break of the masterbatch, showing varying degrees of decline.

[0091] Therefore, the PETG masterbatches of Preparation Examples 1, 5, and 6 were selected for use in the examples.

[0092] 2. The following performance tests were carried out on the PETG transparent shrink films obtained in the examples and comparative examples: Experiments were carried out in accordance with GB / T 1040.3-2006 Determination of tensile properties of plastics (Part 3), QB / T 1130-91 Test method for right-angle tear properties of plastics, and GB / T 2410-2008 Determination of transmittance and haze of transparent plastics; Heat shrinkage rate: The PETG transparent shrink film was placed between two frames, quickly immersed in water in a constant temperature bath at 140 ± 2 °C and timed. During the test process, the specimen should be evenly heated and freely shrunk. After 20 s, the specimen was taken out and immersed in the normal temperature bath medium for cooling. After cooling for 5 s, it was taken out and horizontally static for 10 min. The longitudinal and transverse dimensions of the specimen were measured respectively, and then the heat shrinkage rate was calculated according to the formula. The calculation formula is: Heat shrinkage rate (%) = (dimension before heating - dimension after heating) ÷ dimension before heating × 100%. The specific test data are shown in Table 2.

[0093] Table 2

[0094]

[0095] The process flow chart for the preparation of the PETG transparent shrink film of the present invention is as Figure 1 shown. As can be seen from Table 2, the PETG transparent shrink films prepared in Examples 1-3 have excellent properties (such as Figure 2) It has a high light transmittance, good tensile strength and elongation at break, and a small thermal shrinkage rate, and can be preferably applied to battery labels. Compared with Example 1, the preparation process of the functional enhancement factor used in Examples 4-6 has changed (raw material dosage, raw material composition), resulting in varying degrees of changes in its internal structure and affecting the performance of the final PETG transparent shrink film; in Comparative Example 1, a mixture of Al2O3 and SiO2 is used instead of the functional enhancement factor, and the PETG masterbatch used in Comparative Example 2 is commercially available, both of which will significantly reduce the comprehensive performance of the PETG transparent shrink film.

[0096] 3. Conduct an aging experiment on the PETG transparent shrink film obtained in Example 1: After placing it at 70 °C and 90% humidity for 7 days, conduct tests according to the method described in 2. And use the friction testing machine test method to conduct scratch resistance tests: The friction pressure is 10 N, the friction speed is 100 times / min, and the friction is carried out for 10 min, and observe the scratches on the film surface. The specific data are shown in Table 3.

[0097] Table 3

[0098]

[0099]

[0100] As can be seen from Table 3, the PETG transparent shrink film prepared in Example 1 also has excellent stability and scratch resistance.

[0101] As described above, it is only a preferred embodiment of the present invention and does not impose any form of limitation on this application. Although this application is disclosed as a preferred embodiment above, it is not intended to limit this application. Any person skilled in the art, without departing from the scope of the technical solution of this application, using the technical content disclosed above to make some changes or modifications is equivalent to equivalent implementation cases. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution.

Claims

1. A scratch-resistant PETG transparent shrink film for battery labels, characterized in that, It includes the following raw materials: PETG masterbatch, functional enhancement factor; the raw materials of the functional enhancement factor include Al2O3, SiO2, γ-methacryloxypropyltrimethoxysilane, and poly-3-hydroxyalkanoate.

2. The scratch-resistant PETG transparent shrink film for battery labels according to claim 1, wherein, The preparation method of the PETG masterbatch is as follows: Take terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, polyester, and catalyst and add them to a reaction kettle, stir evenly, under a nitrogen atmosphere, stir and heat up to start the esterification reaction; after the esterification reaction is completed, add a capping agent and mix evenly, then raise the temperature of the reaction kettle to the polycondensation temperature, and at the same time evacuate to start the polycondensation reaction. During this period, control the temperature of the reaction kettle, and finally prepare the PETG masterbatch.

3. The scratch-resistant PETG transparent shrink film for battery labels according to claim 2, wherein The molar ratio of terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol is 4:(2-3):(1-2); the polyester is polybisphenol A terephthalate, and its dosage is 0.5-1.5 wt% of the total mass of terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol.

4. The scratch-resistant PETG transparent shrink film for battery labels according to claim 2, characterized in that The catalyst is one of germanium-based catalysts, titanium-based catalysts, and antimony-based catalysts.

5. The scratch-resistant PETG transparent shrink film for battery labels according to claim 2, wherein The capping agent is glycidyl versatate.

6. The scratch-resistant PETG transparent shrink film for battery labels according to claim 1, wherein The preparation steps of the functional enhancement factor are as follows: Disperse Al2O3 and SiO2 nanoparticles in a solvent, add γ-methacryloxypropyltrimethoxysilane to it, stir and react for 2-4 h, then add a solution of poly-3-hydroxyalkanoate to it, stir and react at room temperature, and remove the solvent to obtain the functional enhancement factor.

7. The scratch-resistant PETG transparent shrink film for battery labels according to claim 6, characterized in that, The dosage ratio of Al2O3 to SiO2 is 1.5:(2-3).

8. The scratch-resistant PETG transparent shrink film for battery labels according to claim 6, characterized in that, The γ-methacryloxypropyltrimethoxysilane is 2-5% of the total mass of Al2O3 and SiO2, and the dosage of the poly-3-hydroxyalkanoate is 10-20% of the total mass of Al2O3 and SiO2.

9. The scratch-resistant PETG transparent shrink film for battery labels according to claim 1, characterized in that, The dosage of the functional enhancement factor is 5-20 wt% of the PETG masterbatch.

10. A method for preparing a scratch-resistant PETG transparent shrink film for battery labels according to any one of claims 1-9, characterized in that, It includes the following preparation steps: Mix the PETG masterbatch and the functional enhancement factor evenly, and through extrusion, casting, stretching, shaping, traction, and winding, prepare the scratch-resistant PETG transparent shrink film for battery labels.

Images