Preparation method of impact-resistant polyester composition

Abstract

The invention provides a preparation method of an impact-resistant polyester composition, which is a continuous process and comprises the following steps. The recycled release film is smashed, compacted and dried, then melt extrusion and degassing are carried out, and the recycled release film contains recycled PET resin. And after filtering, tackifying by using a liquid tackifying system. Next, melting and mulling are carried out, modification extrusion is carried out through modifiers, the modifiers comprise an impact-resistant modifier, a compatilizer, an antioxidant and a lubricant, and after the rubber strip is subjected to water cooling, grain-sized dicing and dehydration are carried out, so that the impact-resistant polyester composition is prepared.

Description

Technical Field

[0001] The present invention relates to a method for preparing a polyester composition and a method for preparing an impact-resistant polyester composition. Background Art

[0002] In response to the carbon reduction and ESG policies of enterprises in various countries, the market is gradually trending towards circular economy and plastic recycling and reuse. On the premise that mechanical properties and processability are not affected, introducing environmentally friendly recycled materials with low carbon emissions will contribute to achieving the global carbon reduction and energy conservation goals. In the development of low-carbon materials, in addition to reducing carbon emissions with recycled materials, production using low-carbon processes is also a key focus for future development.

[0003] In the existing methods for preparing impact-resistant polyester materials by modifying recycled materials, a segmented process is mainly adopted. In each stage of the process, it is necessary to heat up and melt, increase viscosity, and then cool down and pelletize. The repeated heating and cooling will cause waste of energy and an increase in carbon emissions. Therefore, this production method is inefficient and energy-consuming. More specifically, for example, a segmented method of Process 1, Process 2, and Process 3 can be adopted. In Process 1, the recycled release film is crushed, the shredded film is compacted and dried, and then melt-extruded and degassed. After filtration, passing through water-cooled rubber strips, pelletizing, and dehydration, low-viscosity PET recycled pellets can be obtained. Then, Process 2 is carried out. In Process 2, the low-viscosity PET recycled pellets are subjected to solid-state polymerization to form high-viscosity PET recycled pellets. Finally, Process 3 is carried out. In Process 3, the high-viscosity PET recycled pellets are modified by twin-screw kneading using a modifier, and then passed through water-cooled rubber strips, pelletizing, and dehydration to obtain an impact-resistant polyester material.

[0004] Based on the above, developing a method for preparing an impact-resistant polyester composition to improve production efficiency and reduce energy consumption, and thus conform to the global environmental protection trend of plastic reduction and energy conservation, is an important topic that needs to be studied currently. Summary of the Invention

[0005] The present invention provides a method for preparing an impact-resistant polyester composition. Through continuous process modification, the impact resistance of PET materials can be significantly improved, from 3.6 kg-cm / cm to 56.2 kg-cm / cm. Therefore, it can replace ABS, PC, and PP and be applied to injection parts and extruded plates with high impact resistance requirements, such as casings, suitcases, food trays, etc.

[0006] The present invention provides a method for preparing an impact-resistant polyester composition, which is a continuous process and includes the following steps. The recycled release film is crushed, compacted and dried, and then melt extruded and degassed. The recycled release film contains recycled PET resin. After filtration, viscosity increasing is carried out with a liquid viscosity increasing system. Next, melt kneading is carried out, and modification extrusion is carried out with a modifier. The modifier includes an impact modifier, a compatibilizer, an antioxidant and a lubricant. After the rubber strip is cooled by passing through water, it is pelletized and dehydrated to produce the impact-resistant polyester composition.

[0007] In an embodiment of the present invention, the method for preparing the impact-resistant polyester composition further includes removing the surface sizing of the recycled release film and collecting the surface sizing before crushing, compacting and drying the recycled release film.

[0008] In an embodiment of the present invention, the temperature for crushing, compacting and drying the recycled release film is 70°C to 120°C.

[0009] In an embodiment of the present invention, the temperature for melt extrusion and degassing is 240°C to 290°C.

[0010] In an embodiment of the present invention, the temperature for melt kneading is 240°C to 280°C.

[0011] In an embodiment of the present invention, the temperature for modification extrusion is 250°C to 275°C.

[0012] In an embodiment of the present invention, the rubber strip is cooled by passing through water to a temperature of 40°C to 80°C.

[0013] In an embodiment of the present invention, the impact modifier includes a polyolefin elastomer.

[0014] In an embodiment of the present invention, the dispersed particle size of the polyolefin elastomer in the impact-resistant polyester composition is 0.5 μm to 1.2 μm.

[0015] In an embodiment of the present invention, the compatibilizer includes ethylene-methyl acrylate-glycidyl methacrylate copolymer (E-MA-GMA), polyolefin elastomer grafted glycidyl methacrylate (POE-g-GMA), polyethylene grafted glycidyl methacrylate (PE-g-GMA) or a combination thereof.

[0016] In an embodiment of the present invention, the antioxidant includes a hindered phenol antioxidant, a phenolic antioxidant, a mixed antioxidant, a phosphite antioxidant, a composite antioxidant or a combination thereof.

[0017] In an embodiment of the present invention, the lubricant includes stearates, polyethylene wax, silicone modified products or fluorine-based resins.

[0018] In one embodiment of the present invention, based on the total weight of the impact-resistant polyester composition, the content of the recycled PET resin is 70 wt% to 92 wt%, the content of the impact modifier is 5 wt% to 15 wt%, the addition amount of the compatibilizer is 2 wt% to 15 wt%, the content of the antioxidant is 0.1 wt% to 1 wt%, and the content of the lubricant is 0.1 wt% to 1 wt%.

[0019] Based on the above, the present invention provides a method for preparing an impact-resistant polyester composition. Through continuous process modification, the impact strength of the PET material can be significantly improved, from 3.6 kg-cm / cm to 56.2 kg-cm / cm. Therefore, it can replace ABS, PC, and PP and be applied to injection-molded parts and extruded plates with high impact resistance requirements, such as casings, suitcases, and food trays. In addition, the present invention mainly adopts a continuous molten-state feeding modification. In this way, compared with the segmented process in the prior art, it can avoid wasting energy and increasing carbon emissions. Therefore, the preparation method of the present invention is efficient and more energy-saving. Description of the Drawings

[0020] None Detailed Description of the Embodiments

[0021] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are illustrative, and the disclosure of the present invention is not limited thereto.

[0022] In this document, a range represented by "one numerical value to another numerical value" is a summary representation method to avoid listing all the numerical values in the range in the specification one by one. Therefore, the description of a specific numerical range covers any numerical value within the range and a smaller numerical range defined by any numerical value within the range, as if the arbitrary numerical value and the smaller numerical range are written out in the specification.

[0023] The present invention provides a method for preparing an impact-resistant polyester composition, which is a continuous process and includes the following steps. First, remove the surface slurry of the recycled release film and collect the surface slurry. Next, crush, compact, and dry the recycled release film, and then perform melt extrusion and degassing. The recycled release film contains recycled PET resin. After filtration, viscosity increase is carried out with a liquid viscosity-increasing system. Then, melt kneading is performed, and modification extrusion is carried out with a modifier. The modifier includes an impact modifier, a compatibilizer, an antioxidant, and a lubricant. After the rubber strip is cooled by passing through water, it is pelletized and dehydrated to prepare the impact-resistant polyester composition.

[0024] In this embodiment, the surface slurry of the recycled release film is removed and the surface slurry is collected to avoid affecting the hue and properties of the PET recycled pellets. In addition, viscosity increase is carried out using a liquid viscosity increasing system so that the inherent viscosity (IV) increases from a viscosity range of 0.58 dl / g to 0.65 dl / g to a viscosity range of 0.70 dl / g to 0.86 dl / g, and functional modification is carried out to enhance the material strength, processability, and endow the material with functionality during application (such as impact resistance, etc.), so that it can be applied to high-value products such as injection molding and extrusion molding.

[0025] In this embodiment, the temperature for pulverizing, compacting, and drying the recycled release film is, for example, 70°C to 120°C, the temperature for melt extrusion and degassing is, for example, 240°C to 290°C, the temperature for melt kneading is, for example, 240°C to 280°C, the temperature for modified extrusion is, for example, 250°C to 275°C, and the rubber strip is cooled by passing through water to a temperature of, for example, 40°C to 80°C.

[0026] In this embodiment, the modifier may include an impact modifier, a compatibilizer, an antioxidant, and a lubricant. Hereinafter, the above various components will be described in detail.

[0027] In this embodiment, the impact modifier may include a polyolefin elastomer, the compatibilizer may include ethylene-methyl acrylate-glycidyl methacrylate copolymer (E-MA-GMA), polyolefin elastomer grafted glycidyl methacrylate (POE-g-GMA), polyethylene grafted glycidyl methacrylate (PE-g-GMA), or a combination thereof, the antioxidant may include a hindered phenol antioxidant, a phenolic antioxidant, a mixed antioxidant, a phosphite antioxidant, a composite antioxidant, or a combination thereof, and the lubricant may include stearates, polyethylene wax, silicone modified products, or fluorine-based resins. Through compatibility modification, viscosity matching, and kneading and dispersion techniques, the compatibility between the polyolefin elastomer and the polyester material is improved. After adjustment, the dispersed particle size of the polyolefin elastomer in the impact-resistant polyester composition is, for example, 0.5 μm to 1.2 μm, so that the polyester material has characteristics such as high impact resistance strength, high rigidity, low density, and easy processing, and the impact resistance strength can reach 56.2 kg-cm / cm.

[0028] In this embodiment, based on the total weight of the impact-resistant polyester composition, the content of the recycled PET resin is, for example, 70 wt% to 92 wt%, the content of the impact modifier is, for example, 5 wt% to 15 wt%, the addition amount of the compatibilizer is, for example, 2 wt% to 15 wt%, the content of the antioxidant is, for example, 0.1 wt% to 1 wt%, and the content of the lubricant is, for example, 0.1 wt% to 1 wt%.

[0029] In summary, based on the above, the present invention provides a method for preparing an impact-resistant polyester composition. Through continuous process modification, the impact strength of PET materials can be significantly improved, from 3.6 kg-cm / cm to 56.2 kg-cm / cm. Therefore, it can replace ABS, PC, and PP and be applied to injection-molded parts and extruded sheets with high impact resistance requirements, such as casings, suitcases, and food trays. In addition, the present invention mainly adopts continuous molten-state feeding for modification. In this way, compared with the segmented process in the prior art, it can avoid waste of energy and increase in carbon emissions. Therefore, the preparation method of the present invention is highly efficient and more energy-saving. On the other hand, the continuous process of the present invention can reduce the loss of molecular weight or IV caused by repeated heating and cooling of materials, resulting in better impact strength of the impact-resistant modified pellets. (Continuous process of the present invention: 56.2 kg-cm / cm; Conventional segmented process: 43.0 kg-cm / cm) In addition to reducing the yield loss of the segmented process, the continuous process of the present invention is completed under high-temperature melt between each process segment, which can avoid the energy consumption caused by repeated heating and cooling.

Claims

1. A method for preparing an impact-resistant polyester composition, characterized in that: It is a continuous process, including: The recycled release film is crushed, compacted and dried, and then melt-extruded and degassed, wherein the recycled release film contains recycled PET resin; After filtration, thickening is performed with a liquid thickening system; and The rubber strip is melt-mixed and extruded with a modifier, wherein the modifier includes an impact-resistant modifier, a compatibilizer, an antioxidant and a lubricant. The rubber strip is cooled by water and then pelletized and dehydrated to prepare the impact-resistant polyester composition.

2. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The method further includes removing the surface slurry of the recycled release film and collecting the surface slurry before crushing, compacting and drying the recycled release film.

3. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The temperature for crushing, compacting and drying the recovered release film is 70° C. to 120° C.

4. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The temperature of melt extrusion and degassing is 240°C to 290°C.

5. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The temperature for melt kneading is 240°C to 280°C.

6. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The temperature for modified extrusion is 250°C to 275°C.

7. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The strip is cooled in water to a temperature of 40°C to 80°C.

8. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The impact modifier includes a polyolefin elastomer.

9. The method for preparing the impact-resistant polyester composition according to claim 8, characterized in that: The dispersed particle size of the polyolefin elastomer in the impact-resistant polyester composition is 0.5 μm to 1.2 μm.

10. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The compatibilizer includes ethylene-methyl acrylate-glycidyl methacrylate copolymer, polyolefin elastomer grafted glycidyl methacrylate, polyethylene grafted glycidyl methacrylate or a combination thereof.

11. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The antioxidant includes hindered phenol antioxidant, phenolic antioxidant, mixed antioxidant, phosphite antioxidant, composite antioxidant or a combination thereof.

12. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: The lubricant includes stearates, polyethylene wax, modified silicone or fluorine resin.

13. The method for preparing the impact-resistant polyester composition according to claim 1, characterized in that: Based on the total weight of the impact-resistant polyester composition, the content of the recycled PET resin is 70wt% to 92wt%, the content of the impact-resistant modifier is 5wt% to 15wt%, the added amount of the compatibilizer is 2wt% to 15wt%, the content of the antioxidant is 0.1wt% to 1wt%, and the content of the lubricant is 0.1wt% to 1wt%.