PET environment-friendly material and preparation method thereof

Abstract

The invention relates to a PET environment-friendly material and a preparation method thereof, and belongs to the technical field of regenerated environment-friendly materials. The PET environment-friendly material comprises the following components in percentage by weight: 12 to 16 percent of reinforcing filler, 4.2 to 5.8 percent of flexibilizer, 8.2 to 10.5 percent of flame-retardant regenerant, 2.4 to 3 percent of lubricant, 0.13 to 0.17 percent of antioxidant and the balance of regenerated PET, the flame-retardant regenerant is substituted by butyl glycolate and 7-octenyltrichlorosilane to prepare a modified carrier with a branched ester structure and alkenyl, then DOPO and the modified carrier are subjected to double bond addition, and a functional flame-retardant structure is introduced; by introducing the flame-retardant regenerant, the balance of efficient flame retardance and toughening of regenerated PET is realized, and the flame-retardant regenerant is environmentally friendly, has performance advantages and low processing cost, and conforms to the trend of circular economy and green manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycled environmentally friendly materials, and in particular relates to a PET environmentally friendly material and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET) is a high-performance engineering plastic with excellent mechanical strength, heat resistance, and chemical stability. It is widely used in packaging, fibers, electronic devices, and automotive parts. While it is inherently recyclable and environmentally friendly, its actual recycling rate is low, primarily due to the high costs of existing chemical and biological recycling methods. Currently, PET recycling is primarily achieved through physical recycling.

[0003] Physical recycling involves converting waste PET into recycled pellets through processes such as crushing, cleaning, and melt pelletization. These pellets are then modified through blending to impart different properties to meet application requirements. Flame-retardant modification, for example, can be used in engineering materials such as electronics and automotive components, effectively consuming waste PET, enabling efficient recycling and reducing environmental pollution. However, current flame-retardant modification technology for recycled PET faces key challenges. DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) is a commonly used, highly effective flame retardant in PET. However, DOPO has low polarity and poor interfacial compatibility with PET. Furthermore, the presence of a large number of residual impurities in recycled PET complicates its dispersion, leading to a disparity between the amount of flame retardant used and the actual flame retardant effect. Furthermore, the mechanical properties of recycled PET, already deteriorating due to molecular chain breakage and decreased crystallinity, are further exacerbated by the added DOPO flame retardant. Conventional blending processes struggle to balance flame retardancy and mechanical properties. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a PET environmentally friendly material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A PET environmentally friendly material comprises: 12-16 wt% of a reinforcing filler, 4.2-5.8 wt% of a toughening agent, 8.2-10.5 wt% of a flame retardant regeneration agent, 2.4-3 wt% of a lubricant, 0.13-0.17 wt% of an antioxidant, and the balance being recycled PET.

[0006] Among them, the flame retardant regeneration agent is made by the following method: Step A1: Butyl glycolate and anhydrous tetrahydrofuran were mixed, and dry nitrogen was introduced to replace the air in the reaction system. The temperature was adjusted to 0-5°C in an ice-water bath. 7-octenyltrichlorosilane was slowly added with stirring and the reaction was carried out for 1.5-2 hours. After returning to room temperature, triethylamine was added and the reaction was continued for 0.5-0.8 hours. The mixture was filtered and the tetrahydrofuran was removed by rotary evaporation to obtain a modified support. Furthermore, the amount ratio of 7-octenyltrichlorosilane, butyl glycolate, triethylamine and anhydrous tetrahydrofuran is 10 mmol:30 mmol:4.2-5.5 mL:30-35 mL, and the active chlorosilane substitution reaction of butyl glycolate and 7-octenyltrichlorosilane is carried out. The specific reaction route is as follows:

[0007] Step A2: DOPO and dioxane are mixed, and then the modified carrier is added and mixed. The mixture is heated to 45-60°C, and boron trifluoride ether is slowly added and stirred to react for 2.8-3.5 hours. The mixture is then heated and refluxed for 1-1.3 hours. Water is added to wash the mixture, and the precipitate is vacuum dried to obtain a flame retardant regeneration agent. Furthermore, the ratio of the modified support, DOPO, boron trifluoride etherate, and dioxane is 10 mmol: 10 mmol: 0.1-0.12 mL: 40-50 mL, and DOPO undergoes an addition reaction with the unsaturated double bond in the modified support. The specific reaction route is as follows:

[0008] Preferably, the reinforcing filler is silane-modified silica.

[0009] Preferably, the toughening agent is POE-g-MAH.

[0010] Preferably, the lubricant is compounded from silicone powder and ethylene bisstearamide.

[0011] A method for preparing an environmentally friendly PET material comprises the following steps: mixing a toughening agent, a flame retardant regeneration agent, a lubricant, an antioxidant and recycled PET, feeding the mixture from a main feeding port of an extruder, feeding a reinforcing filler from a side feeding port, plasticizing and mixing the mixture, and then extruding and pelletizing the mixture to obtain the environmentally friendly PET material.

[0012] Preferably, the temperature of each extrusion section during the plasticizing and mixing process is set as follows: feeding section: 250-260°C, compression section 260-270°C, homogenization section 270-285°C, and die section 260-270°C.

[0013] Beneficial effects of the present invention: The present invention is based on environmentally friendly recycled PET materials and realizes high-performance reuse of recycled PET by introducing a developed flame retardant regeneration agent for blending and modification. The flame retardant regeneration agent is substituted by butyl glycolate and 7-octenyltrichlorosilane to prepare a modified carrier having a branched ester structure and an olefin group. DOPO is then added to the double bond to introduce a functional flame retardant structure. Compared with existing recycled flame retardant PET materials, the flame retardant regeneration agent of the present invention contains a branched butyl ester structure modification in the molecule, matches the polarity of PET, has good compatibility, can be effectively dispersed during the melt mixing process, and has good compatibility during the molding and cooling process. During the combustion process, the branched butyl ester structure can entangle with the PET molecular chain, reducing the thermal migration of the DOPO functional structure, and then stably dispersed in the recycled PET, quickly forming a continuous and dense protective layer when the material burns, effectively isolating heat and oxygen, and significantly improving the limiting oxygen index of the material. The continuous and uniform protective layer inhibits the generation of molten droplets, thereby achieving an excellent flame retardant effect. In addition, the evenly dispersed DOPO has little effect on the mechanical properties of the substrate, and the branched butyl ester short chain acts as a flexible spacer segment to reduce stress concentration, forming a uniform toughening effect, which can significantly improve the strength and toughness of the material. DETAILED DESCRIPTION

[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0015] Example 1: Preparation of environmentally friendly PET material, as follows: (1) Preparation of flame retardant regeneration agent Step A1: Butyl glycolate and anhydrous tetrahydrofuran were mixed, dry nitrogen was introduced to replace the air in the reaction system, the temperature was adjusted to 0°C in an ice-water bath, 7-octenyltrichlorosilane was slowly added with stirring, and the reaction was continued for 2 hours. After returning to room temperature, triethylamine was added and the reaction was continued for 0.8 hours. The amount ratio of 7-octenyltrichlorosilane, butyl glycolate, triethylamine and anhydrous tetrahydrofuran was 10 mmol: 30 mmol: 4.2 mL: 30 mL. After filtration, tetrahydrofuran was removed by rotary evaporation to obtain a modified support.

[0016] Step A2: DOPO and dioxane are mixed, and then the modified carrier is added and mixed. The temperature is raised to 45°C, and boron trifluoride etherate is slowly added and stirred to react for 3.5 hours. Then, the temperature is raised to reflux for 1.3 hours. The usage ratio of the modified carrier, DOPO, boron trifluoride etherate and dioxane is 10 mmol: 10 mmol: 0.1 mL: 40 mL. Water is added to wash and the precipitate is vacuum dried to obtain a flame retardant regeneration agent.

[0017] (2) Preparation of environmentally friendly PET materials Ingredients: 12 wt % reinforcing filler, selected from XD-S10H5 silane-modified silica; 5.8 wt % toughening agent, selected from CMG5805 POE-g-MAH (maleic anhydride grafted POE); 8.2 wt % flame retardant regeneration agent, prepared in this example; 2.4 wt % lubricant, selected from KJ-B01 silicone powder and industrial-grade ethylene bisstearamide in an equal weight ratio; 0.13 wt % antioxidant, selected from antioxidant 1010 and antioxidant 168 in an equal weight ratio; the balance is recycled PET, selected from GL-018085 pellets.

[0018] Melt granulation: The toughening agent, flame retardant regeneration agent, lubricant, antioxidant and recycled PET are mixed and fed from the main feeding port of the extruder, and the reinforcing filler is fed from the side feeding port. The temperature of each section of the extruder is set as follows: feeding section (zone 1: 250℃), compression section (zone 2: 260℃, zone 3: 270℃), homogenizing section (zone 4: 270℃, zone 5: 270℃), and die section (zone 6: 260℃). After plasticizing and mixing the components, they are extruded and pelletized to obtain PET environmentally friendly materials.

[0019] Example 2, preparation of PET environmentally friendly material, specifically as follows: (1) Preparation of flame retardant regeneration agent Step A1: Butyl glycolate and anhydrous tetrahydrofuran were mixed, dry nitrogen was introduced to replace the air in the reaction system, the temperature was adjusted to 5°C in an ice-water bath, 7-octenyltrichlorosilane was slowly added with stirring, and the reaction was continued for 1.5 hours. After returning to room temperature, triethylamine was added and the reaction was continued for 0.5 hours. The amount ratio of 7-octenyltrichlorosilane, butyl glycolate, triethylamine and anhydrous tetrahydrofuran was 10 mmol: 30 mmol: 5.5 mL: 35 mL. After filtration, tetrahydrofuran was removed by rotary evaporation to obtain a modified support.

[0020] Step A2: DOPO and dioxane are mixed, and then the modified carrier is added and mixed. The temperature is raised to 60°C, and boron trifluoride etherate is slowly added and stirred to react for 2.8 hours. Then the temperature is raised to reflux for 1 hour. The usage ratio of the modified carrier, DOPO, boron trifluoride etherate and dioxane is 10 mmol:10 mmol:0.12 mL:50 mL. Water is added to wash and the precipitate is vacuum dried to obtain a flame retardant regeneration agent.

[0021] (2) Preparation of environmentally friendly PET materials Ingredients: 16 wt % reinforcing filler, selected from XD-S10H5 silane-modified silica; 4.2 wt % toughening agent, selected from CMG5805 POE-g-MAH (maleic anhydride grafted POE); 10.5 wt % flame retardant regeneration agent, prepared in this example; 3 wt % lubricant, selected from KJ-B01 silicone powder and industrial-grade ethylene bisstearamide in an equal weight ratio; 0.17 wt % antioxidant, selected from antioxidant 1010 and antioxidant 168 in an equal weight ratio; the balance is recycled PET, selected from GL-018085 pellets.

[0022] Melt granulation: The toughening agent, flame retardant regeneration agent, lubricant, antioxidant and recycled PET are mixed and fed from the main feeding port of the extruder, and the reinforcing filler is fed from the side feeding port. The temperature of each section of the extruder is set as follows: feeding section (zone 1: 260℃), compression section (zone 2: 270℃, zone 3: 270℃), homogenization section (zone 4: 280℃, zone 5: 285℃), die section (zone 6: 270℃). After plasticizing and mixing the components, they are extruded and pelletized to obtain PET environmentally friendly materials.

[0023] Example 3, preparation of PET environmentally friendly material, specifically as follows: (1) Preparation of flame retardant regeneration agent Step A1: Butyl glycolate and anhydrous tetrahydrofuran were mixed, dry nitrogen was introduced to replace the air in the reaction system, the temperature was adjusted to 5°C in an ice-water bath, 7-octenyltrichlorosilane was slowly added with stirring, and the reaction was continued for 1.8 hours. After returning to room temperature, triethylamine was added and the reaction was continued for 0.6 hours. The amount ratio of 7-octenyltrichlorosilane, butyl glycolate, triethylamine and anhydrous tetrahydrofuran was 10 mmol:30 mmol:4.8 mL:30 mL. After filtration, tetrahydrofuran was removed by rotary evaporation to obtain a modified support.

[0024] Step A2: DOPO and dioxane are mixed, and then the modified carrier is added and mixed. The temperature is raised to 55°C, and boron trifluoride etherate is slowly added and stirred to react for 3 hours. Then the temperature is raised to reflux for 1.1 hours. The usage ratio of the modified carrier, DOPO, boron trifluoride etherate and dioxane is 10 mmol:10 mmol:0.11 mL:45 mL. Water is added to wash and the precipitate is vacuum dried to obtain a flame retardant regeneration agent.

[0025] (2) Preparation of environmentally friendly PET materials Ingredients: 14 wt% reinforcing filler, selected from XD-S10H5 silane-modified silica; 5 wt% toughening agent, selected from CMG5805 POE-g-MAH (maleic anhydride grafted POE); 9.4 wt% flame retardant regeneration agent, prepared in this example; 2.6 wt% lubricant, selected from KJ-B01 silicone powder and industrial-grade ethylene bisstearamide in an equal weight ratio; 0.15 wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in an equal weight ratio; the balance is recycled PET, selected from GL-018085 pellets.

[0026] Melt granulation: The toughening agent, flame retardant regeneration agent, lubricant, antioxidant and recycled PET are mixed and fed from the main feeding port of the extruder, and the reinforcing filler is fed from the side feeding port. The temperature of each section of the extruder is set as follows: feeding section (zone 1: 255°C), compression section (zone 2: 260°C, zone 3: 270°C), homogenizing section (zone 4: 270°C, zone 5: 280°C), and die section (zone 6: 265°C). After plasticizing and mixing the components, they are extruded and pelletized to obtain PET environmentally friendly materials.

[0027] Example 4, preparation of PET environmentally friendly material, specifically as follows: (1) Preparation of flame retardant regeneration agent Step A1: Butyl glycolate and anhydrous tetrahydrofuran were mixed, dry nitrogen was introduced to replace the air in the reaction system, the temperature was adjusted to 0°C in an ice-water bath, 7-octenyltrichlorosilane was slowly added with stirring, and the reaction was continued for 2 hours. After returning to room temperature, triethylamine was added and the reaction was continued for 0.6 hours. The amount ratio of 7-octenyltrichlorosilane, butyl glycolate, triethylamine and anhydrous tetrahydrofuran was 10 mmol: 30 mmol: 4.5 mL: 35 mL. After filtration, tetrahydrofuran was removed by rotary evaporation to obtain a modified support.

[0028] Step A2: DOPO and dioxane are mixed, and then the modified carrier is added and mixed. The temperature is raised to 50°C, and boron trifluoride etherate is slowly added and stirred to react for 3.2 hours. Then, the temperature is raised to reflux for 1.2 hours. The usage ratio of the modified carrier, DOPO, boron trifluoride etherate and dioxane is 10 mmol: 10 mmol: 0.1 mL: 50 mL. Water is added to wash and the precipitate is vacuum dried to obtain a flame retardant regeneration agent.

[0029] (2) Preparation of environmentally friendly PET materials Ingredients: 15 wt % reinforcing filler, selected from XD-S10H5 silane-modified silica; 5.3 wt % toughening agent, selected from CMG5805 POE-g-MAH (maleic anhydride grafted POE); 9.8 wt % flame retardant regeneration agent, prepared in this example; 2.7 wt % lubricant, selected from KJ-B01 silicone powder and industrial-grade ethylene bisstearamide in an equal weight ratio; 0.15 wt % antioxidant, selected from antioxidant 1010 and antioxidant 168 in an equal weight ratio; the balance is recycled PET, selected from GL-018085 pellets.

[0030] Melt granulation: The toughening agent, flame retardant regeneration agent, lubricant, antioxidant and recycled PET are mixed and fed from the main feeding port of the extruder, and the reinforcing filler is fed from the side feeding port. The temperature of each section of the extruder is set as follows: feeding section (zone 1: 255℃), compression section (zone 2: 265℃, zone 3: 275℃), homogenization section (zone 4: 280℃, zone 5: 280℃), die section (zone 6: 265℃). After plasticizing and mixing the components, they are extruded and pelletized to obtain PET environmentally friendly materials.

[0031] In Comparative Example 1, referring to Example 4, the flame retardant regenerating agent was replaced with DOPO in an amount equal to the phosphorus content, and the balance was supplemented with the toughening agent to 100 wt%.

[0032] In Comparative Example 2, referring to Example 4, the flame retardant regenerating agent was replaced with DOPO-ITA in an amount equal to the phosphorus content, and the balance was supplemented with the toughening agent to 100 wt%.

[0033] The environmentally friendly PET material prepared as described above was molded into sheet specimens using a flat mold at 260°C and 15 MPa. The tensile properties of the specimens were tested according to ASTM D638-2022, with the test specimen size being Type I and the tensile rate being 50 mm / min. The impact properties of the specimens were tested according to ASTM D256-1997. The limiting oxygen index of the specimens was tested according to ASTM D2863-2023. The 1.6 mm thick specimens were tested using the vertical burning method according to UL94, and the burning time and dripping behavior were recorded to determine the flame retardancy level. The specific test results are shown in Table 1: Table 1 Tensile strength / MPa Limiting oxygen index / % <![CDATA[Impact strength kJ·m -2 > UL94 rating Example 1 42.5 31.9 8.9 V-0 Example 2 48.9 33.2 8.2 V-0 Example 3 44.1 32.4 9.1 V-0 Example 4 46.3 32.7 9.5 V-0 Comparative Example 1 37.3 27.9 4.9 V-2 Comparative Example 2 40.7 29.3 6.4 V-2 In the above tests, the tensile strength and impact strength of the sample of the embodiment are higher than those of the comparative example, showing excellent toughness. The limiting oxygen index of the embodiment is above 31.9%, showing high flame retardancy. In the continuous ignition test, the embodiment reaches the V-0 standard, while the comparative example has obvious molten droplets, and the flame retardancy level can only meet the V-2 standard.

[0034] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0035] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A PET environmentally friendly material, characterized in that: The specific components are: reinforcing filler 12-16wt%, toughening agent 4.2-5.8wt%, flame retardant regeneration agent 8.2-10.5wt%, lubricant 2.4-3wt% and antioxidant 0.13-0.17wt%, and the balance is recycled PET; The flame retardant regeneration agent is prepared by the following method: Step A1: Butyl glycolate and anhydrous tetrahydrofuran were mixed, and dry nitrogen was introduced to replace the air in the reaction system. The temperature was adjusted to 0-5°C in an ice-water bath. 7-octenyltrichlorosilane was slowly added with stirring and the reaction was carried out for 1.5-2 hours. After returning to room temperature, triethylamine was added and the reaction was continued for 0.5-0.8 hours. The mixture was filtered and the tetrahydrofuran was removed by rotary evaporation to obtain a modified support. Step A2: DOPO and dioxane are mixed, and then the modified carrier is added and mixed. The temperature is raised to 45-60° C., and boron trifluoride ether is slowly added and stirred to react for 2.8-3.5 hours. Then, the temperature is raised to reflux for 1-1.3 hours, and water is added for washing. The precipitate is taken and vacuum dried to obtain a flame retardant regeneration agent.

2. The environmentally friendly PET material according to claim 1, characterized in that: The usage ratio of 7-octenyltrichlorosilane, butyl glycolate, triethylamine and anhydrous tetrahydrofuran is 10 mmol:30 mmol:4.2-5.5 mL:30-35 mL.

3. The environmentally friendly PET material according to claim 2, characterized in that: The usage ratio of the modified carrier, DOPO, boron trifluoride etherate and dioxane is 10 mmol: 10 mmol: 0.1-0.12 mL: 40-50 mL.

4. The environmentally friendly PET material according to claim 1, characterized in that: The reinforcing filler is silane-modified silica.

5. The environmentally friendly PET material according to claim 1, characterized in that: The toughening agent is POE-g-MAH.

6. The environmentally friendly PET material according to claim 1, characterized in that: The lubricant is compounded from silicone powder and ethylene bisstearamide.

7. A method for preparing the environmentally friendly PET material according to any one of claims 1 to 6, characterized in that: Specifically, the toughening agent, flame retardant regeneration agent, lubricant, antioxidant and recycled PET are mixed and fed from the main feeding port of the extruder, and the reinforcing filler is fed from the side feeding port. After plasticizing and mixing, the mixture is extruded and pelletized to obtain PET environmentally friendly material.

8. The method for preparing an environmentally friendly PET material according to claim 7, characterized in that: During the plasticizing and mixing process, the temperature of each extrusion section was set as follows: feeding section: 250-260°C, compression section 260-270°C, homogenization section 270-285°C, and die section 260-270°C.

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