A pet-based packing tape and a method of manufacturing the same

Abstract

The application relates to the technical field of packing tapes, in particular to a PET-based packing tape and a preparation method thereof. The PET-based packing tape is prepared through the following steps: in step one, PET resin, a flame retardant, modified silicon dioxide and an additive are uniformly mixed, extruded through a double-screw extruder, and cut into particles to obtain PET flame-retardant master batches; in step two, the PET flame-retardant master batches and the PET resin are uniformly mixed, melted through a single-screw extruder, and extruded into a blank tape; the blank tape is cooled, heated, traction-stretched, cooled, wound and packaged to obtain the PET-based packing tape. The PET-based packing tape prepared by the application has excellent flame-retardant performance and mechanical properties, and also has excellent aging resistance, so that the service life of the packing tape is prolonged.

Description

Technical Field

[0001] This invention relates to the field of packing tape technology, specifically to a PET-based packing tape and its preparation method. Background Technology

[0002] PET (polyethylene terephthalate) based strapping is widely used in various packaging fields, such as logistics and building materials, due to its excellent physical properties and superior corrosion resistance. PET strapping not only has excellent tensile strength and abrasion resistance, but also good flexibility, allowing it to maintain stability when binding and securing items. Furthermore, PET material has good recyclability, aligning with modern environmental protection principles.

[0003] However, traditional packing straps have significant shortcomings in flame retardancy. PET, as a combustible material, has a low limiting oxygen index (LOI), making it prone to combustion and potentially producing molten droplets when exposed to open flames or high-temperature heat sources, thus limiting its application in situations with high fire protection requirements. On the other hand, conventional PET packing straps have poor temperature resistance, easily undergoing creep and strength decay at high temperatures, while becoming more brittle at low temperatures. Their weather resistance is also insufficient; under long-term exposure to ultraviolet radiation, humidity, and other natural climatic conditions, they are prone to aging, leading to a decline in mechanical properties and affecting service life and reliability.

[0004] To address the above issues, we propose a PET-based packing tape and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a PET-based packing tape and its preparation method to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing PET-based packing tape includes the following steps:

[0008] Step 1: Mix PET resin, flame retardant, modified silica and additives evenly, extrude through a twin-screw extruder, and pelletize to obtain PET flame retardant masterbatch;

[0009] Step 2: Mix PET flame retardant masterbatch and PET resin evenly, melt them through a single screw extruder, extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap.

[0010] Furthermore, the PET flame retardant masterbatch is prepared from the following components in parts by weight: 400-500 parts PET resin, 300-350 parts flame retardant, 40-80 parts modified silica, and 20-30 parts additives.

[0011] Furthermore, the mass ratio of the PET flame retardant masterbatch to the PET resin is 1:(2-3).

[0012] Furthermore, the flame retardant is a coated modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0013] Step A: Methacrylamide chitosan and 2,3,4-trihydroxybenzaldehyde are mixed and dispersed in ethanol, stirred at 80-90℃ for 10-12h, and after filtration, washing and drying, modified chitosan is obtained;

[0014] Step B: Mix the modified chitosan and acetic acid solution evenly, add sodium phytate solution dropwise over 1-2 hours, stir at 45-55℃ for 1-2 hours, and obtain chitosan-based flame retardant after centrifugation, washing and drying.

[0015] Step C: Ultrasonically mix aluminum diethylphosphonate, methyl methacrylate and chitosan-based flame retardant for 15-30 min, add Tween-80 and ethylene glycol dimethacrylate, stir evenly at 70-80℃, add sodium dodecylbenzenesulfonate aqueous solution dropwise over 1-2 h, add azobisisobutyronitrile, and continue the reaction for 3-5 h. After centrifugation, washing and drying, the coated modified aluminum diethylphosphonate is obtained.

[0016] Further, in step A, the mass ratio of the methacrylated chitosan, 2,3,4-trihydroxybenzaldehyde and ethanol is 1:(0.5-1.0):(20-30).

[0017] Further, in step B, the mass ratio of the modified chitosan, acetic acid solution and sodium phytate solution is 1:(20-30):(10-15), the concentration of the acetic acid solution is 1-3wt%, and the concentration of the sodium phytate solution is 3-5wt%.

[0018] Further, in step C, the mass ratio of aluminum diethylphosphinic acid, methyl methacrylate, and chitosan-based flame retardant is 1:(0.8-1.0):(0.3-0.5).

[0019] Further, the mass ratio of aluminum diethylphosphinic acid, Tween-80 and ethylene glycol dimethacrylate is 1:(0.05-0.10):(0.1-0.3).

[0020] Furthermore, the concentration of the sodium dodecylbenzenesulfonate aqueous solution is 0.1-0.2 mol / L.

[0021] Furthermore, the amount of azobisisobutyronitrile used is 1-3% of the total mass of aluminum diethylphosphinic acid, methyl methacrylate and chitosan-based flame retardant.

[0022] Furthermore, the method for preparing the modified silica is as follows:

[0023] Aminated silica was ultrasonically dispersed in tetrahydrofuran. Triethylamine and quercetin were added under ice bath conditions. Diphenylphosphine chloride was added under nitrogen protection. After reacting for 2-4 hours, the temperature was raised to 40-50℃ and reacted for 3-5 hours. After filtration, washing and drying, modified silica was obtained.

[0024] Further, the mass ratio of the aminated silica, tetrahydrofuran, triethylamine, quercetin and diphenylphosphine chloride is 1:(40-50):(2-4):(0.3-0.5):(1-2).

[0025] Furthermore, the additive is composed of 3-5 parts antioxidant, 10-15 parts lubricant and 7-10 parts coupling agent.

[0026] Furthermore, the extrusion temperature of the twin-screw extruder is 220-250℃, and the screw speed is 400-500 r / min.

[0027] Furthermore, the temperatures of each section of the single-screw extruder are as follows: Section 1 temperature 230-250℃, Section 2 temperature 250-260℃, Section 3 temperature 250-260℃, Section 4 temperature 245-255℃, and Section 5 temperature 245-255℃.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. This invention prepares an intumescent flame retardant, namely a chitosan-based flame retardant, by grafting the UV stabilizer 2,3,4-trihydroxybenzaldehyde (THBA) onto methacrylamide chitosan to inhibit its migration and precipitation, and by using electrostatic interaction to coat sodium phytate onto the modified chitosan surface. By combining sodium phytate as an acid source with modified chitosan as a char source, a dense and robust intumescent char layer is formed on the material surface during combustion, effectively isolating heat and oxygen, inhibiting further polymer decomposition and the escape of combustibles, and also effectively resisting UV damage, thus extending the service life of the packing strap. Furthermore, by in-situ polymerization of methyl methacrylate (MMA) and the chitosan-based flame retardant on aluminum diethylphosphonate (ADP), coated modified aluminum diethylphosphonate is obtained, further improving the material's compatibility and flame retardant properties. In addition, the addition of modified silica further enhances the strength and stability of the char layer, effectively preventing molten dripping during combustion and improving fire safety.

[0030] 2. This invention uses aminated silica, quercetin, and diphenylphosphine as raw materials to prepare modified silica. The modified silica acts as a synergistic flame retardant, which not only enhances mechanical properties but also effectively inhibits heat transfer and the generation of toxic fumes during combustion. At the same time, quercetin, as a natural antioxidant, can improve the antioxidant properties of the material, further enhancing the stability and reliability of the packing strap during long-term storage and use. The use of environmentally friendly materials (such as chitosan and quercetin) for modification improves the environmental friendliness of the packing strap, meeting the modern market's demand for green materials. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that there are no special restrictions on the purchasers of all raw materials involved in this invention. Exemplary examples include (in this embodiment) PET resin: grade SBG80, purchased from Dongguan Yihe Plastics Import & Export Co., Ltd.; Aminated silica: model XFB36, purchased from Xianfeng Nano; Antioxidant: Antioxidant 1010; Lubricant: Italian brand PETS-AP; Coupling agent: 3-aminopropyltriethoxysilane.

[0033] Unless otherwise specified, all the following quantities are parts by weight.

[0034] Example 1: A method for preparing PET-based packing tape, comprising the following processes:

[0035] Step 1: Mix 400 parts PET resin, 300 parts flame retardant, 40 parts modified silica, 3 parts antioxidant, 10 parts lubricant and 7 parts coupling agent evenly, and extrude through a twin-screw extruder at an extrusion temperature of 220℃ and a screw speed of 400r / min. Then, granulate to obtain PET flame retardant masterbatch.

[0036] Step 2: Mix PET flame retardant masterbatch and PET resin evenly at a mass ratio of 1:2, melt them through a single screw extruder (section 1 temperature 230℃, section 2 temperature 250℃, section 3 temperature 250℃, section 4 temperature 245℃, section 5 temperature 245℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0037] The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0038] Step A: Mix methacrylamide chitosan, 2,3,4-trihydroxybenzaldehyde and ethanol at a mass ratio of 1:0.5:20 until homogeneous, stir at 80°C for 10 hours, and obtain modified chitosan after filtration, washing and drying.

[0039] Step B: Dissolve 90 parts of modified chitosan in 1800 parts of 1wt% acetic acid solution, add 900 parts of 3wt% sodium phytate solution dropwise over 1 hour, stir at 45°C for 1 hour, and obtain chitosan-based flame retardant after centrifugation, washing and drying.

[0040] Step C: 300 parts of aluminum diethylphosphonate, 240 parts of methyl methacrylate and 90 parts of chitosan-based flame retardant were ultrasonically mixed for 15 min. 15 parts of Tween-80 and 30 parts of ethylene glycol dimethacrylate were added and stirred evenly at 70℃. 2000 parts of 0.1 mol / L sodium dodecylbenzenesulfonate aqueous solution were added dropwise over 1 h. 7.5 parts of azobisisobutyronitrile were added and the reaction continued for 3 h. After centrifugation, washing and drying, coated modified aluminum diethylphosphonate was obtained.

[0041] The preparation method of modified silica is as follows:

[0042] 40 parts of aminated silica were ultrasonically dispersed in 1600 parts of tetrahydrofuran. 80 parts of triethylamine and 12 parts of quercetin were added under ice bath conditions. Under nitrogen protection, 40 parts of diphenylphosphine chloride were added. After reacting for 2 hours, the temperature was raised to 40°C and reacted for 3 hours. After filtration, washing and drying, modified silica was obtained.

[0043] Example 2: A method for preparing PET-based packing tape, comprising the following processes:

[0044] Step 1: Mix 450 parts PET resin, 330 parts flame retardant, 60 parts modified silica, 4 parts antioxidant, 12 parts lubricant and 8 parts coupling agent evenly, and extrude through a twin-screw extruder at an extrusion temperature of 230℃ and a screw speed of 450r / min. Then, granulate to obtain PET flame retardant masterbatch.

[0045] Step 2: Mix PET flame retardant masterbatch and PET resin at a mass ratio of 1:2.5 until uniform, melt the mixture through a single screw extruder (section 1 temperature 240℃, section 2 temperature 255℃, section 3 temperature 255℃, section 4 temperature 250℃, section 5 temperature 250℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0046] The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0047] Step A: Mix methacrylated chitosan, 2,3,4-trihydroxybenzaldehyde and ethanol at a mass ratio of 1:0.8:25 until homogeneous. Stir at 85°C for 11 hours. After filtration, washing and drying, modified chitosan is obtained.

[0048] Step B: Mix the modified chitosan and 2wt% acetic acid solution evenly, add 4wt% sodium phytate solution dropwise over 1.5 hours, stir at 50°C for 1.5 hours, and obtain chitosan-based flame retardant after centrifugation, washing and drying.

[0049] Step C: 330 parts of aluminum diethylphosphonate, 290 parts of methyl methacrylate and 130 parts of chitosan-based flame retardant were ultrasonically mixed for 20 min. 25 parts of Tween-80 and 65 parts of ethylene glycol dimethacrylate were added and stirred evenly at 75 °C. 2500 parts of 0.15 mol / L sodium dodecylbenzenesulfonate aqueous solution were added dropwise over 1.5 h. 15 parts of azobisisobutyronitrile were added and the reaction was continued for 4 h. After centrifugation, washing and drying, coated modified aluminum diethylphosphonate was obtained.

[0050] The preparation method of modified silica is as follows:

[0051] 60 parts of aminated silica were ultrasonically dispersed in 2700 parts of tetrahydrofuran. 180 parts of triethylamine and 30 parts of quercetin were added under ice bath conditions. Under nitrogen protection, 90 parts of diphenylphosphine chloride were added. After reacting for 3 hours, the temperature was raised to 45°C and reacted for 4 hours. After filtration, washing and drying, modified silica was obtained.

[0052] Example 3: A method for preparing PET-based packing tape, comprising the following processes:

[0053] Step 1: Mix 500 parts of PET resin, 350 parts of flame retardant, 80 parts of modified silica, 5 parts of antioxidant, 15 parts of lubricant and 10 parts of coupling agent evenly, and extrude through a twin-screw extruder at an extrusion temperature of 250℃ and a screw speed of 500r / min. Cut into pellets to obtain PET flame retardant masterbatch.

[0054] Step 2: Mix PET flame retardant masterbatch and PET resin at a mass ratio of 1:3 until homogeneous, melt the mixture through a single screw extruder (section 1 temperature 250℃, section 2 temperature 260℃, section 3 temperature 260℃, section 4 temperature 255℃, section 5 temperature 255℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0055] The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0056] Step A: Methacrylamide chitosan, 2,3,4-trihydroxybenzaldehyde, and ethanol were mixed at a mass ratio of 1:1:30 and stirred at 90°C for 12 hours. After filtration, washing, and drying, modified chitosan was obtained.

[0057] Step B: Dissolve 175 parts of modified chitosan in 5250 parts of 3wt% acetic acid solution, add 2625 parts of 5wt% sodium phytate solution dropwise over 2 hours, stir at 55℃ for 2 hours, and obtain chitosan-based flame retardant after centrifugation, washing and drying.

[0058] Step C: 350 parts of aluminum diethylphosphonate, 350 parts of methyl methacrylate and 175 parts of chitosan-based flame retardant were ultrasonically mixed for 30 min. 35 parts of Tween-80 and 105 parts of ethylene glycol dimethacrylate were added and stirred evenly at 80℃. 3000 parts of 0.2 mol / L sodium dodecylbenzenesulfonate aqueous solution were added dropwise over 2 h. 26 parts of azobisisobutyronitrile were added and the reaction was continued for 5 h. After centrifugation, washing and drying, coated modified aluminum diethylphosphonate was obtained.

[0059] The preparation method of modified silica is as follows:

[0060] 80 parts of aminated silica were ultrasonically dispersed in 4000 parts of tetrahydrofuran. 320 parts of triethylamine and 40 parts of quercetin were added under ice bath conditions. Under nitrogen protection, 160 parts of diphenylphosphine chloride were added. After reacting for 4 hours, the temperature was raised to 50°C and reacted for 5 hours. After filtration, washing and drying, modified silica was obtained.

[0061] Comparative Example 1: A method for preparing PET-based strapping, comprising the following processes:

[0062] Step 1: Mix 450 parts of PET resin, 330 parts of flame retardant, 4 parts of antioxidant, 12 parts of lubricant and 8 parts of coupling agent evenly, extrude through a twin-screw extruder at an extrusion temperature of 230℃ and a screw speed of 450r / min, and granulate to obtain PET flame retardant masterbatch;

[0063] Step 2: Mix PET flame retardant masterbatch and PET resin at a mass ratio of 1:2.5 until uniform, melt the mixture through a single screw extruder (section 1 temperature 240℃, section 2 temperature 255℃, section 3 temperature 255℃, section 4 temperature 250℃, section 5 temperature 250℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0064] The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0065] Step A: Mix methacrylated chitosan, 2,3,4-trihydroxybenzaldehyde and ethanol at a mass ratio of 1:0.8:25 until homogeneous. Stir at 85°C for 11 hours. After filtration, washing and drying, modified chitosan is obtained.

[0066] Step B: Mix the modified chitosan and 2wt% acetic acid solution evenly, add 4wt% sodium phytate solution dropwise over 1.5 hours, stir at 50°C for 1.5 hours, and obtain chitosan-based flame retardant after centrifugation, washing and drying.

[0067] Step C: 330 parts of aluminum diethylphosphonate, 290 parts of methyl methacrylate and 130 parts of chitosan-based flame retardant were ultrasonically mixed for 20 min. 25 parts of Tween-80 and 65 parts of ethylene glycol dimethacrylate were added and stirred evenly at 75 °C. 2500 parts of 0.15 mol / L sodium dodecylbenzenesulfonate aqueous solution were added dropwise over 1.5 h. 15 parts of azobisisobutyronitrile were added and the reaction was continued for 4 h. After centrifugation, washing and drying, coated modified aluminum diethylphosphonate was obtained.

[0068] Compared with Example 2, Comparative Example 1 did not introduce modified silica, and the other steps were the same as in Example 2.

[0069] Comparative Example 2: A method for preparing PET-based strapping, comprising the following processes:

[0070] Step 1: Mix 450 parts of PET resin, 330 parts of aluminum diethylphosphinate, 60 parts of modified silica, 4 parts of antioxidant, 12 parts of lubricant and 8 parts of coupling agent evenly, and extrude through a twin-screw extruder at an extrusion temperature of 230℃ and a screw speed of 450r / min. Then, pelletize to obtain PET flame retardant masterbatch.

[0071] Step 2: Mix PET flame retardant masterbatch and PET resin at a mass ratio of 1:2.5 until uniform, melt the mixture through a single screw extruder (section 1 temperature 240℃, section 2 temperature 255℃, section 3 temperature 255℃, section 4 temperature 250℃, section 5 temperature 250℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0072] The preparation method of modified silica is as follows:

[0073] 60 parts of aminated silica were ultrasonically dispersed in 2700 parts of tetrahydrofuran. 180 parts of triethylamine and 30 parts of quercetin were added under ice bath conditions. Under nitrogen protection, 90 parts of diphenylphosphine chloride were added. After reacting for 3 hours, the temperature was raised to 45°C and reacted for 4 hours. After filtration, washing and drying, modified silica was obtained.

[0074] Compared with Example 2, Comparative Example 2 replaced the flame retardant with the same mass of aluminum diethylphosphonate, and the other steps were the same as in Example 2.

[0075] Comparative Example 3: A method for preparing PET-based strapping, comprising the following processes:

[0076] Step 1: Mix 450 parts PET resin, 330 parts flame retardant, 60 parts modified silica, 4 parts antioxidant, 12 parts lubricant and 8 parts coupling agent evenly, and extrude through a twin-screw extruder at an extrusion temperature of 230℃ and a screw speed of 450r / min. Then, granulate to obtain PET flame retardant masterbatch.

[0077] Step 2: Mix PET flame retardant masterbatch and PET resin at a mass ratio of 1:2.5 until uniform, melt the mixture through a single screw extruder (section 1 temperature 240℃, section 2 temperature 255℃, section 3 temperature 255℃, section 4 temperature 250℃, section 5 temperature 250℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0078] The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0079] Step A: Mix methacrylated chitosan, 2,3,4-trihydroxybenzaldehyde and ethanol at a mass ratio of 1:0.8:25 until homogeneous. Stir at 85°C for 11 hours. After filtration, washing and drying, modified chitosan is obtained.

[0080] Step B: Mix the modified chitosan and 2wt% acetic acid solution evenly, add 4wt% sodium phytate solution dropwise over 1.5 hours, stir at 50°C for 1.5 hours, and obtain chitosan-based flame retardant after centrifugation, washing and drying.

[0081] Step C: 330 parts of aluminum diethylphosphonate, 290 parts of methyl methacrylate and 130 parts of chitosan-based flame retardant were ultrasonically mixed for 20 min. 25 parts of Tween-80 and 65 parts of ethylene glycol dimethacrylate were added and stirred evenly at 75 °C. 2500 parts of 0.15 mol / L sodium dodecylbenzenesulfonate aqueous solution were added dropwise over 1.5 h. 15 parts of azobisisobutyronitrile were added and the reaction was continued for 4 h. After centrifugation, washing and drying, coated modified aluminum diethylphosphonate was obtained.

[0082] The preparation method of modified silica is as follows:

[0083] 60 parts of aminated silica were ultrasonically dispersed in 2700 parts of tetrahydrofuran. 180 parts of triethylamine were added under ice bath conditions. Under nitrogen protection, 90 parts of diphenylphosphine chloride were added. After reacting for 3 hours, the temperature was raised to 45°C and reacted for 4 hours. After filtration, washing and drying, modified silica was obtained.

[0084] Compared to Example 2, Comparative Example 3 did not introduce quercetin into the modified silica, and the other steps were the same as in Example 2.

[0085] Comparative Example 4: A method for preparing PET-based strapping, comprising the following processes:

[0086] Step 1: Mix 450 parts of PET resin, 330 parts of aluminum diethylphosphinate, 60 parts of modified silica, 4 parts of antioxidant, 12 parts of lubricant and 8 parts of coupling agent evenly, and extrude through a twin-screw extruder at an extrusion temperature of 230℃ and a screw speed of 450r / min. Then, pelletize to obtain PET flame retardant masterbatch.

[0087] Step 2: Mix PET flame retardant masterbatch and PET resin at a mass ratio of 1:2.5 until uniform, melt the mixture through a single screw extruder (section 1 temperature 240℃, section 2 temperature 255℃, section 3 temperature 255℃, section 4 temperature 250℃, section 5 temperature 250℃), extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap;

[0088] The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows:

[0089] 330 parts of aluminum diethylphosphinate and 290 parts of methyl methacrylate were ultrasonically mixed for 20 min. 25 parts of Tween-80 and 65 parts of ethylene glycol dimethacrylate were added and stirred evenly at 75 °C. 2500 parts of 0.15 mol / L sodium dodecylbenzenesulfonate aqueous solution were added dropwise over 1.5 h. 15 parts of azobisisobutyronitrile were added and the reaction was continued for 4 h. After centrifugation, washing and drying, coated modified aluminum diethylphosphinate was obtained.

[0090] The preparation method of modified silica is as follows:

[0091] 60 parts of aminated silica were ultrasonically dispersed in 2700 parts of tetrahydrofuran. 180 parts of triethylamine and 30 parts of quercetin were added under ice bath conditions. Under nitrogen protection, 90 parts of diphenylphosphine chloride were added. After reacting for 3 hours, the temperature was raised to 45°C and reacted for 4 hours. After filtration, washing and drying, modified silica was obtained.

[0092] Compared with Example 2, Comparative Example 4 did not introduce chitosan flame retardant, and the other steps were the same as in Example 2.

[0093] Experiment: PET-based packing tapes obtained in Examples 1-3 and Comparative Examples 1-4 were used to prepare samples. Their performance was tested, and the results were recorded.

[0094] Flame retardant performance: The flame retardant performance of the packing straps was tested by vertical burning according to the UL94 test standard; Tensile strength: Tested according to GB / T 1040 using a microcomputer-controlled electronic universal testing machine with a tensile rate of 50 mm / min. The higher the tensile strength, the better the mechanical properties; Aging resistance test: The sample was placed at a temperature of 85℃ and a humidity of 85% for 1000 hours, and then its tensile strength retention rate was tested.

[0095] The test results are shown in Table 1.

[0096] Table 1. Test results of relevant performance of PET-based strapping

[0097]

[0098] Based on the data in the table above, the following conclusions can be clearly drawn:

[0099] Based on Examples 1-3 and Comparative Examples 1-4, it can be seen that the PET-based packing tape prepared by the present invention has excellent flame retardant and mechanical properties, as well as excellent aging resistance. The flame retardant properties, tensile strength, and tensile strength retention rate of the products obtained in Comparative Examples 1 and 2 all decreased, indicating that the modified silica and the coated modified aluminum diethylphosphinate have a synergistic flame retardant effect, which can improve the flame retardant rating of the packing tape. The tensile strength retention rate of the product obtained in Comparative Example 3 decreased, indicating that the introduction of quercetin in the present invention can improve the aging resistance of the packing tape. The flame retardant properties, tensile strength, and tensile strength retention rate of the product obtained in Comparative Example 4 all decreased, indicating that the chitosan-based flame retardant prepared by the present invention has excellent flame retardant effect and mechanical properties, thereby improving the overall performance of the material.

[0100] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing PET-based packing tape, characterized in that: Includes the following steps: Step 1: Mix PET resin, flame retardant, modified silica and additives evenly, extrude through a twin-screw extruder, and pelletize to obtain PET flame retardant masterbatch; Step 2: Mix PET flame retardant masterbatch and PET resin evenly, melt them through a single screw extruder, extrude a blank strip, cool, heat, stretch, cool, wind up, and package the blank strip to obtain a PET-based packing strap; The PET flame retardant masterbatch is prepared from the following components in parts by weight: 400-500 parts PET resin, 300-350 parts flame retardant, 40-80 parts modified silica, and 20-30 parts additives. The flame retardant is a coated and modified aluminum diethylphosphinate, and the specific modification process is as follows: Step A: Methacrylamide chitosan and 2,3,4-trihydroxybenzaldehyde are mixed and dispersed in ethanol, stirred at 80-90℃ for 10-12h, and after filtration, washing and drying, modified chitosan is obtained; Step B: Mix the modified chitosan and acetic acid solution evenly, add sodium phytate solution dropwise over 1-2 hours, stir at 45-55℃ for 1-2 hours, and obtain chitosan-based flame retardant after centrifugation, washing and drying. Step C: Ultrasonically mix aluminum diethylphosphonate, methyl methacrylate and chitosan-based flame retardant for 15-30 min, add Tween-80 and ethylene glycol dimethacrylate, stir evenly at 70-80℃, add sodium dodecylbenzenesulfonate aqueous solution dropwise over 1-2 h, add azobisisobutyronitrile, and continue the reaction for 3-5 h. After centrifugation, washing and drying, the coated modified aluminum diethylphosphonate is obtained. The method for preparing the modified silica is as follows: Aminated silica was ultrasonically dispersed in tetrahydrofuran, and triethylamine and quercetin were added under ice bath conditions. Under nitrogen protection, diphenylphosphine chloride was added. After reacting for 2-4 hours, the temperature was raised to 40-50℃ and reacted for 3-5 hours. After filtration, washing and drying, modified silica was obtained. The mass ratio of the PET flame retardant masterbatch to PET resin is 1:(2-3).

2. The method for preparing a PET-based packing strap according to claim 1, characterized in that: In step A, the mass ratio of the methacrylated chitosan, 2,3,4-trihydroxybenzaldehyde and ethanol is 1:(0.5-1.0):(20-30).

3. The method for preparing a PET-based packing strap according to claim 1, characterized in that: In step B, the mass ratio of the modified chitosan, acetic acid solution and sodium phytate solution is 1:(20-30):(10-15), the concentration of the acetic acid solution is 1-3wt%, and the concentration of the sodium phytate solution is 3-5wt%.

4. The method for preparing a PET-based packing strap according to claim 1, characterized in that: The additive is composed of 3-5 parts antioxidant, 10-15 parts lubricant and 7-10 parts coupling agent.

5. The method for preparing a PET-based packing strap according to claim 1, characterized in that: The extrusion temperature of the twin-screw extruder is 220-250℃, and the screw speed is 400-500 r / min.

6. A PET-based packing tape prepared by the preparation method according to any one of claims 1-5.

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