PCR (Polymerase Chain Reaction) modified plastic applied to code scanner and preparation method of PCR modified plastic

Abstract

The invention relates to the technical field of high-performance polycarbonate modified plastics, in particular to a PCR (Polymerase Chain Reaction) modified plastic applied to a code scanner and a preparation method of the PCR modified plastic. The nano functional filler comprises a nano core, a polymer shell layer coated on the surface of the core, and a functionalized molecular halo region formed on the outer side of the shell layer; 5-15 parts of a reinforcing and toughening system and 3-10 parts of a thermoplastic elastomer; and 0.5-3 parts of an additive. By adopting the design of dynamic reversible chemical bonds, the thermal stability and mechanical properties of the PCR modified plastic are remarkably improved, the material is ensured to still maintain excellent physical properties in a high-temperature environment, and the material is suitable for various industrial applications with strict requirements. And the characteristic provides reliable guarantee for the use of the material in a high-temperature working environment.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance polycarbonate modified plastics, and in particular to a PCR modified plastic used in a barcode scanner and a preparation method thereof. Background Art

[0002] In recent years, PCR (polycarbonate)-modified plastics have been widely used in various plastic products due to their excellent mechanical properties and thermal stability. However, existing technologies still face numerous challenges in practical application. These challenges primarily include insufficient thermal deformation resistance at high temperatures, poor processing performance and stability, and insufficient toughness.

[0003] Specifically, traditional PCR-modified materials are prone to deformation under high-temperature conditions, resulting in performance degradation in certain industrial applications. For example, in the manufacture of automotive and electronic components, materials must withstand high temperatures, and existing PCR plastics often experience thermal deformation, impacting the overall safety and reliability of the product. Furthermore, during molding processes such as injection molding or extrusion, traditional materials lack fluidity, which can easily lead to uneven mold filling and a high rate of molding defects, reducing production efficiency and material utilization.

[0004] On the other hand, existing toughening technologies often perform well only under static loads, but exhibit significant fatigue losses under dynamic loads and lack sufficient impact resistance. This makes products susceptible to breakage or failure in practical applications, especially in environments subject to frequent shock or vibration. Furthermore, these traditional modified materials have poor environmental adaptability and are affected by factors such as humidity and temperature, resulting in unstable material properties.

[0005] Therefore, to overcome these shortcomings in the existing technology, there is an urgent need for a new type of PCR-modified plastic that not only exhibits excellent mechanical properties and thermal stability, but also maintains excellent processing performance and toughness under various processing conditions to meet the increasing demands of modern industry for materials. By designing dynamic reversible chemical bonds, multilayered nano-functional fillers, and a reinforcing and toughening system, the present invention provides a novel solution to these problems, opening up new prospects for the application of PCR plastics. Summary of the Invention

[0006] The purpose of the present invention is to provide a PCR modified plastic for use in a barcode scanner and a preparation method thereof, which solves the technical problems of existing PCR materials such as thermal deformation, insufficient processing performance and low structural toughness under high temperature environments.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A PCR modified plastic used in a barcode scanner comprises the following components, calculated in parts by weight: 65-88 parts of a modified polycarbonate matrix, wherein the modified polycarbonate matrix is ​​prepared by reacting 100 parts of post-consumer recycled polycarbonate with 0.5-7 parts of a polymer modifier, wherein the polymer modifier is used to form a topological network comprising dynamically reversible chemical bonds in the polycarbonate; 3-15 parts of a multilayer nano-functional filler, wherein the nano-functional filler comprises: a nano-core, a polymer shell layer covering the surface of the core, and a functionalized molecular halo region formed outside the shell layer; 5-15 reinforcement and toughening system, comprising 1-5 parts of a polymer capable of forming an in-situ microfiber network in the modified polycarbonate matrix, and 3-10 parts of a thermoplastic elastomer, wherein the thermoplastic elastomer is orderly distributed within the confined space formed by the microfiber network; 0.5-3 parts additives; The modified polycarbonate matrix is ​​created by reacting post-consumer recycled polycarbonate (PCR) with a polymer modifier to form a topological network of dynamically reversible chemical bonds. This mechanism significantly enhances the physical properties of polycarbonate, increasing its strength, toughness, and heat resistance while maintaining its processability. In this way, the modified polycarbonate matrix can better adapt to process requirements such as injection molding and provides a foundation for the effective integration of subsequent fillers and reinforcement and toughening systems.

[0008] The composition contains 3-15 parts of a multilayered nano-functional filler structured with a nano-core, a polymer shell, and a functionalized molecular halo. This multilayered design not only provides the material with increased strength and stiffness but also enhances its overall performance by optimizing filler dispersion. The nano-core ensures excellent interaction between the filler and the polycarbonate matrix, while the gradient modulus design of the polymer shell ensures excellent filler dispersion within the polycarbonate matrix, thus avoiding common sedimentation issues.

[0009] To enhance the material's toughness and impact resistance, the composition also contains 1-5 parts of a polymer capable of forming an in-situ microfiber network within the modified polycarbonate matrix, and 3-10 parts of a thermoplastic elastomer. This toughening and strengthening system, through the in-situ synthesis of the microfiber network, provides an effective toughening mechanism, enabling the material to effectively disperse and absorb stress when subjected to external impact, thus preventing brittle fracture. Furthermore, the ordered distribution of the thermoplastic elastomer within the microfiber network further enhances the material's flexibility and durability, making it suitable for the complex environments encountered during actual use of barcode scanners.

[0010] The 0.5-3 parts of additives in the composition are mainly used to improve the processing properties of the material and prolong the storage stability. By adding different types of additives in appropriate amounts, the fluidity and antioxidant properties of the material can be adjusted, thereby further improving the quality and durability of the finished product.

[0011] Preferably, the polymer modifier is a bisoxazoline-terminated oligosiloxane.

[0012] Preferably, the nano-core of the multi-layered nano-functional filler is nano-aluminum nitride or nano-diamond with a chemically treated surface; the polymer shell is a gradient modulus polymer layer formed on the surface of the core by in situ polymerization; and the functionalized molecular halo region comprises a fluorine-containing polymer segment or a segment that can interact with the dynamic reversible chemical bonds in the modified polycarbonate matrix.

[0013] Preferably, the polymer that forms the microfiber network in situ in the modified polycarbonate matrix is ​​a thermotropic liquid crystal polymer; and the thermoplastic elastomer is a polyester thermoplastic elastomer.

[0014] The present invention also provides a method for preparing a PCR-modified plastic for use in a barcode scanner, comprising the following steps: Step 1: melt-reacting and extruding post-consumer recycled polycarbonate and a polymer modifier in a first reaction extrusion device to obtain a modified polycarbonate masterbatch containing a dynamic reversible chemical bond topology network precursor; Step 2: melt-blending the modified polycarbonate masterbatch obtained in step 1 with other components in a second blending and extrusion device to obtain a PCR modified plastic composition; The preparation method of the present invention comprises two main steps: first, reacting recycled polycarbonate with a polymer modifier via melt reactive extrusion to form a modified polycarbonate masterbatch; then, in a second stage, melt blending this masterbatch with other components to produce the final PCR-modified plastic composition. The innovation of this method lies in the precise control of reaction conditions, which makes the production process of the modified polycarbonate masterbatch more controllable, facilitates the subsequent blending process, and improves the consistency and reliability of material properties.

[0015] In step two, the different components are fed sequentially into the extruder using a staged feeding method to ensure optimal heat transfer and mixing. This process design ensures uniform dispersion of the multilayered nano-functional filler while effectively preventing thermal degradation and cross-linking of the polymer, thereby enhancing its performance.

[0016] By activating the nanocore surface and constructing a functionalized molecular halo, the interaction between the nanofiller and the polycarbonate matrix is ​​further enhanced, improving the mechanical properties and chemical stability of the finished material. This cutting-edge preparation method not only improves material processing efficiency but also effectively reduces costs, making this PCR-modified plastic have broad application prospects in fields such as barcode scanners.

[0017] Preferably, the temperature of the reaction zone of the first stage melt reaction extrusion in step 1 is 230-270° C., and the screw speed is 100-350 rpm.

[0018] Preferably, the components in step 2 include multilayer nano-functional fillers, polymers capable of forming an in-situ microfiber network in a modified polycarbonate matrix, thermoplastic elastomers and additives, wherein the nano-functional fillers are dispersed at the nanoscale, the polymer forms an in-situ microfiber network, and the thermoplastic elastomer is distributed in an ordered manner in the microfiber network.

[0019] Preferably, the second stage precision melt blending and structure control extrusion in step 2 adopts a segmented feeding method, and the modified PCR-PC masterbatch is added in sequence, and then the multi-layer structure nano-functional filler, the polymer capable of forming a microfiber network in situ in the modified polycarbonate matrix and the thermoplastic elastomer are added at different positions downstream.

[0020] Preferably, before step 2, a multilayered nano-functional filler is prepared by surface activating the nano-core, in situ polymerizing and coating the activated core surface with a polymer shell, and constructing a functionalized molecular halo region outside the shell. Preferably, in step 2, the second blending and extrusion equipment is provided with at least two stages of vacuum exhaust ports, and the operating vacuum degree is 0.08-0.098 MPa.

[0021] In summary, the present invention includes at least one of the following beneficial technical effects: 1. This invention significantly improves the thermal stability and mechanical properties of PCR-modified plastics by employing a design with dynamically reversible chemical bonds. This optimized chemical structure effectively resists thermal deformation, ensuring that the material maintains excellent physical properties even in high-temperature environments, making it suitable for a variety of demanding industrial applications. This property provides reliable protection for the material's use in high-temperature operating environments.

[0022] 2. This invention enhances the processing performance and toughness of PCR-modified plastics through the use of multi-layered nano-functional fillers. The composite filler of aluminum nitride and polylactic acid optimizes the material's fluidity and filling capacity, enabling better stress dispersion and reduced defect rates during the injection molding process. This feature offers advantages for large-scale production and high-efficiency processing, making the material adaptable to diverse production processes.

[0023] 3. The toughening system of this invention combines a thermotropic liquid crystal polymer with a thermoplastic elastomer to form a high-performance, compatible network. This innovative design not only enhances the material's impact resistance but also maintains excellent toughness under dynamic strain, significantly reducing the risk of fracture. This advantage enables the material to demonstrate greater reliability in complex operating environments, meeting diverse application requirements.

[0024] 4. This invention achieves high molding stability during the production process. Its excellent melt index and corresponding processing window ensure that the material consistently fills the mold quickly and evenly under varying molding conditions, reducing downtime and maintenance requirements during production. This not only improves production efficiency but also reduces operating costs for businesses. DETAILED DESCRIPTION

[0025] The present invention is described in further detail.

[0026] Example 1 Material preparation; Post-consumer recycled polycarbonate (PCR-PC): 100 parts; Polymer modifier (bisoxazoline-terminated oligosiloxane): 3.5 parts; Nano core (aluminum nitride): 5 parts; Polymer shell (polylactic acid PLA): 2 parts; Functionalized molecule (polyvinyl fluoride): 2 parts; Thermotropic liquid crystal polymer in the strengthening and toughening system: 3 parts; Thermoplastic elastomer (polyester): 5 parts; Additives (antioxidants): 1 part.

[0027] Preparation steps Preparation of modified polycarbonate matrix: 100 parts of PCR-PC and 3.5 parts of polymer modifier were added simultaneously to the first reactive extruder.

[0028] The reaction temperature was adjusted to 250° C., the screw speed was set to 200 rpm, and melt reaction extrusion was performed for 30 minutes to obtain a modified polycarbonate masterbatch with a dynamic reversible chemical bond topology network.

[0029] Preparation of multilayer nano-functional fillers: 5 parts of aluminum nitride were surface activated, and then 2 parts of polylactic acid (PLA) were in situ polymerized on the surface to form a polymer shell layer.

[0030] Two parts of polyvinyl fluoride are used to construct a functionalized molecular halo region, and after thorough mixing, a multilayered nano-functional filler is obtained.

[0031] Preparation of reinforcement and toughening system: 3 parts of thermotropic liquid crystal polymer and 5 parts of polyester-based thermoplastic elastomer were mixed and melt-mixed at 220° C. for 15 minutes to construct a microfiber network structure.

[0032] Preparation of PCR modified plastic composition: The modified polycarbonate masterbatch was melt-blended with 5 parts of multilayer nano-functional filler, 3 parts of thermotropic liquid crystal polymer and 5 parts of polyester thermoplastic elastomer in a second blending extruder. The reaction zone temperature was maintained at 240°C, the screw speed was set to 250 rpm, and the mixing time was 20 minutes.

[0033] Performance evaluation of the final product: Evaluate the physical properties of materials through tensile testing, impact testing, and heat deflection temperature testing.

[0034] Example 2 Material preparation; Post-consumer recycled polycarbonate (PCR-PC): 100 parts; Polymer modifier (bisoxazoline-terminated oligosiloxane): 0.5 parts; Nano core (aluminum nitride): 3 parts; Polymer shell (polylactic acid PLA): 1 part; Functionalized molecule (polyvinyl fluoride): 1 part; Thermotropic liquid crystal polymer in the strengthening and toughening system: 1 part; Thermoplastic elastomer (polyester): 3 parts; Additives (antioxidants): 0.5 parts.

[0035] Preparation steps: Preparation of modified polycarbonate matrix: 100 parts of PCR-PC and 0.5 parts of polymer modifier were added simultaneously to the first reactive extruder.

[0036] The reaction temperature was adjusted to 230° C., the screw speed was set to 150 rpm, and melt reaction extrusion was performed for 20 minutes to obtain modified polycarbonate masterbatch.

[0037] Preparation of multilayer nano-functional fillers: 3 parts of aluminum nitride were surface activated, and then 1 part of polylactic acid was in situ polymerized on the surface to form a polymer shell layer.

[0038] One part of polyvinyl fluoride is used to construct a functional molecular halo region, and after thorough mixing, a multilayered nano-functional filler is obtained.

[0039] Preparation of reinforcement and toughening system: 1 part of thermotropic liquid crystal polymer was mixed with 3 parts of polyester-based thermoplastic elastomer and melt-mixed at 210° C. for 10 minutes to construct a microfiber network structure.

[0040] Preparation of PCR modified plastic composition: The modified polycarbonate masterbatch was melt-blended with 3 parts of multilayer nano-functional filler, 1 part of thermotropic liquid crystal polymer and 3 parts of polyester thermoplastic elastomer in a second blending extruder. The reaction zone temperature was maintained at 230°C, the screw speed was set to 200 rpm, and the mixing time was 15 minutes.

[0041] Performance evaluation of the final product: Evaluate the physical properties of materials through tensile testing, impact testing, and heat deflection temperature testing.

[0042] Example 3 Materials preparation: Post-consumer recycled polycarbonate (PCR-PC): 100 parts; Polymer modifier (bisoxazoline-terminated oligosiloxane): 7 parts; Nano core (aluminum nitride): 15 parts; Polymer shell (polylactic acid PLA): 5 parts; Functionalized molecule (polyvinyl fluoride): 3 parts; Thermotropic liquid crystal polymer in the strengthening and toughening system: 5 parts; Thermoplastic elastomer (polyester): 10 parts; Additives (antioxidants): 3 parts.

[0043] Preparation steps: Preparation of modified polycarbonate matrix: 100 parts of PCR-PC and 7 parts of polymer modifier were added simultaneously to the first reactive extruder.

[0044] The reaction temperature was adjusted to 270° C., the screw speed was set to 350 rpm, and melt reaction extrusion was performed for 40 minutes to obtain a modified polycarbonate masterbatch with a dynamic reversible chemical bond topology network.

[0045] Preparation of multilayer nano-functional fillers: 15 parts of aluminum nitride were surface activated, and then 5 parts of polylactic acid were in situ polymerized on the surface to form a polymer shell layer.

[0046] Three parts of polyvinyl fluoride are used to construct a functional molecular halo region, and after thorough mixing, a multilayered nano-functional filler is obtained.

[0047] Preparation of reinforcement and toughening system: 5 parts of thermotropic liquid crystal polymer were mixed with 10 parts of polyester-based thermoplastic elastomer and melt-mixed at 250° C. for 20 minutes to construct a microfiber network structure.

[0048] Preparation of PCR modified plastic composition: The modified polycarbonate masterbatch was melt-blended with 15 parts of multilayer nano-functional filler, 5 parts of thermotropic liquid crystal polymer and 10 parts of polyester thermoplastic elastomer in a second blending extruder. The reaction zone temperature was maintained at 260°C, the screw speed was set to 300 rpm, and the mixing time was 25 minutes.

[0049] Performance evaluation of the final product: Evaluate the physical properties of materials through tensile testing, impact testing, and heat deflection temperature testing.

[0050] Comparative Example 1: Compared with Example 1, the difference is that the amount of the polymer modifier used is reduced to 2 parts, and the rest are the same.

[0051] Comparative Example 2: Compared with Example 1, the difference is that the amount of the nano core is reduced from aluminum nitride to 3 parts, and the rest are the same.

[0052] Comparative Example 3: Compared with Example 1, the difference is that the polymer shell is reduced from polylactic acid to 1 part, and some functionalized molecular halo regions are omitted, and the rest are the same.

[0053] Comparative Example 4: Compared with Example 1, the difference is that the amount of thermotropic liquid crystal polymer is reduced to 1 part, and the microfiber network structure is no longer constructed. The rest is the same.

[0054] Comparative Example 5: Compared with Example 1, the difference is that the amount of polyester thermoplastic elastomer is reduced to 3 parts, and the additives are omitted, and the rest are the same.

[0055] Comparative Example 6: Compared with Example 1, the difference is that the reaction temperature is lowered to 220° C. and the screw speed is reduced to 150 rpm, and the rest are the same.

[0056] Comparative Example 7: Compared with Example 1, the difference is that the in-situ polymerization process is omitted in the preparation steps of the multilayered nano-functional filler, and the rest are the same.

[0057] Comparative Example 8: Compared with Example 1, the difference is that the mixing time in the reaction extrusion process is reduced to 10 minutes, and the rest are the same.

[0058] Comparative Example 9: Compared with Example 1, the difference is that the amount of PCR-PC is reduced to 80 parts, and the rest are the same.

[0059] Experiment 1: Mechanical properties test Experimental Materials: The PCR modified plastic of Example 1; The PCR modified plastic of Comparative Example 1; The PCR modified plastic of Comparative Example 2; The PCR modified plastic of Comparative Example 3; The PCR modified plastic of Comparative Example 4; The PCR modified plastic of Comparative Example 5; The PCR modified plastic of Comparative Example 6; The PCR modified plastic of Comparative Example 7; The PCR modified plastic of Comparative Example 8; The PCR modified plastic of Comparative Example 9.

[0060] Experimental equipment: Universal material testing machine (for tensile strength testing) Izod impact testing machine (for impact toughness testing) Standard experimental specimen mold (preparing tensile specimens according to ASTMD638 standard and impact specimens according to ISO180 standard) experimental steps Sample preparation: Samples of PCR-modified plastics of each formulation were taken and standard-sized tensile and impact specimens were produced using an injection molding machine under identical process conditions. The specimens were cut to the specified size to ensure a smooth, defect-free surface.

[0061] Tensile strength test: Place the prepared tensile specimen on the universal materials testing machine, ensuring that the grips are properly fixed.

[0062] Set the loading speed to 50 mm / min and start the equipment for tensile testing.

[0063] Record the maximum tensile stress of each specimen (unit: MPa).

[0064] Impact toughness test: Fix the impact specimen in the test position of the Izod impact tester, ensuring that the notched side of the specimen faces outward.

[0065] Set the impact energy to a standard value and perform an impact test.

[0066] Record the absorbed energy of each sample (unit: J / cm 2 ).

[0067] Table 1: Tensile strength and impact toughness test data Sample name tensile strength Impact toughness Example 1 72.3 15.5 Comparative Example 1 65.1 10.2 Comparative Example 2 68.5 12 Comparative Example 3 58.9 9.8 Comparative Example 4 62 8.5 Comparative Example 5 70.2 13.4 Comparative Example 6 55.7 7.1 Comparative Example 7 66.8 11.3 Comparative Example 8 60.1 10 Comparative Example 9 73.5 14.8 According to Table 1 above, we can see that: In this experiment, mechanical property testing of the PCR-modified plastics of Example 1 and Comparative Examples 1 to 9 revealed that Example 1 exhibited significant advantages in tensile strength and impact toughness. Combined with the use of a modified polycarbonate matrix, the experimental results demonstrate that the formation of dynamically reversible chemical bonds effectively enhances the material's overall structural stability and energy absorption performance. This chemical structure design not only enhances its guiding properties but also, through its combination of continuity and low ductility, effectively disperses stress and reduces local strain when subjected to force.

[0068] Secondly, the innovative multilayered nano-functional filler design significantly improves the material's mechanical properties. The experimental results above show that the combination of aluminum nitride and polylactic acid used in Example 1 not only improves the filler's dispersion within the polymer matrix but also enhances interfacial adhesion through interlayer interactions, improving load transfer from the polycarbonate matrix to the nanofiller. This synergistic effect gives Example 1 superior impact toughness compared to the comparative examples, particularly under dynamic strain conditions, effectively dissipating kinetic energy and thus improving the material's impact resistance.

[0069] Finally, the application of the strengthening and toughening system has also shown significant effects in improving material properties. Combining the design concept of thermotropic liquid crystal polymers and polyester thermoplastic elastomers, this innovative strategy further improves the toughness and tensile strength of the material by forming a microfiber network structure. When stress is applied, the interaction between the polymers not only effectively delays the propagation of cracks, but also disperses the concentrated stress through plastic deformation, thereby increasing impact resistance. Therefore, the high mechanical properties demonstrated in Example 1 are the result of the mutual coupling and comprehensive effect of various innovative elements and mechanisms, which fully reflects the superiority and feasibility of modified polycarbonate materials in practical applications.

[0070] Experiment 2: Thermal Performance Test Experimental Materials: The PCR modified plastic of Example 1; The PCR modified plastic of Comparative Example 1; The PCR modified plastic of Comparative Example 2; The PCR modified plastic of Comparative Example 3; The PCR modified plastic of Comparative Example 4; The PCR modified plastic of Comparative Example 5; The PCR modified plastic of Comparative Example 6; The PCR modified plastic of Comparative Example 7; The PCR modified plastic of Comparative Example 8; The PCR modified plastic of Comparative Example 9.

[0071] Experimental equipment: Vicat softening point tester (for heat deformation temperature testing); Thermomechanical Analyzer (TMA, for thermal expansion coefficient testing); Experimental steps: Sample preparation: Samples were taken from each formulation of PCR-modified plastic and standard-sized test specimens were prepared using the same mold to ensure smooth surface and consistent thickness for easy testing.

[0072] Heat deformation temperature test: Place the sample on the support frame of the Vicat softening point tester, ensure that the sample is in the correct position, and pre-set the loading weight (e.g. 1 kg).

[0073] Set the heating rate to 50°C / h, start the equipment to heat, and monitor the deformation state of the sample at the same time.

[0074] Record the temperature at which the specimen begins to deform as the thermal deformation temperature. Perform at least three tests to ensure the accuracy of the data.

[0075] Thermal expansion coefficient test: Use a thermomechanical analyzer to test. Place the sample on the sample holder of the TMA, ensuring that the sample is flat and in good contact with the measurement probe.

[0076] The set temperature range was from room temperature (about 25°C) to 200°C, and the heating rate was set at 10°C / min.

[0077] Record the change in length of the specimen during heating to calculate the coefficient of thermal expansion. Repeat the experiment at least twice and take the average value to improve the reliability of the results.

[0078] Data recording and analysis: Summarizing the test data of each sample, comparing the performance differences in heat deformation temperature and thermal expansion coefficient between Example 1 and each comparative example, it can be seen from Table 1 above that: In this experiment, mechanical property testing of the PCR-modified plastics of Example 1 and Comparative Examples 1 to 9 revealed that Example 1 exhibited significant advantages in tensile strength and impact toughness. Combined with the use of a modified polycarbonate matrix, the experimental results demonstrate that the formation of dynamically reversible chemical bonds effectively enhances the material's overall structural stability and energy absorption performance. This chemical structure design not only enhances its guiding properties but also, through its combination of continuity and low ductility, effectively disperses stress and reduces local strain when subjected to force.

[0079] Secondly, the innovative multilayered nano-functional filler design significantly improves the material's mechanical properties. The experimental results above show that the combination of aluminum nitride and polylactic acid used in Example 1 not only improves the filler's dispersion within the polymer matrix but also enhances interfacial adhesion through interlayer interactions, improving load transfer from the polycarbonate matrix to the nanofiller. This synergistic effect gives Example 1 superior impact toughness compared to the comparative examples, particularly under dynamic strain conditions, effectively dissipating kinetic energy and thus improving the material's impact resistance.

[0080] Finally, the application of the strengthening and toughening system has also shown significant effects in improving material properties. Combining the design concept of thermotropic liquid crystal polymers and polyester thermoplastic elastomers, this innovative strategy further improves the toughness and tensile strength of the material by forming a microfiber network structure. When stress is applied, the interaction between the polymers not only effectively delays the propagation of cracks, but also disperses the concentrated stress through plastic deformation, thereby increasing impact resistance. Therefore, the high mechanical properties demonstrated in Example 1 are the result of the mutual coupling and comprehensive effect of various innovative elements and mechanisms, which fully reflects the superiority and feasibility of modified polycarbonate materials in practical applications.

[0081] Experiment 2: Thermal Performance Test Experimental Materials: The PCR modified plastic of Example 1; The PCR modified plastic of Comparative Example 1; The PCR modified plastic of Comparative Example 2; The PCR modified plastic of Comparative Example 3; The PCR modified plastic of Comparative Example 4; The PCR modified plastic of Comparative Example 5; The PCR modified plastic of Comparative Example 6; The PCR modified plastic of Comparative Example 7; The PCR modified plastic of Comparative Example 8; The PCR modified plastic of Comparative Example 9.

[0082] Experimental equipment: Vicat softening point tester (for heat deformation temperature testing); Thermomechanical Analyzer (TMA, for thermal expansion coefficient testing); Experimental steps: Sample preparation: Samples were taken from each formulation of PCR-modified plastic and standard-sized test specimens were prepared using the same mold to ensure smooth surface and consistent thickness for easy testing.

[0083] Heat deformation temperature test: Place the sample on the support frame of the Vicat softening point tester, ensure that the sample is in the correct position, and pre-set the loading weight (e.g. 1 kg).

[0084] Set the heating rate to 50°C / h, start the equipment for heating, and monitor the deformation state of the sample at the same time.

[0085] Record the temperature at which the specimen begins to deform as the thermal deformation temperature. Perform at least three tests to ensure the accuracy of the data.

[0086] Thermal expansion coefficient test: Use a thermomechanical analyzer to test. Place the sample on the sample holder of the TMA, ensuring that the sample is flat and in good contact with the measurement probe.

[0087] The set temperature range was from room temperature (about 25°C) to 200°C, and the heating rate was set at 10°C / min.

[0088] Record the change in length of the specimen during heating to calculate the thermal expansion coefficient. Repeat the experiment at least twice and take the average value to improve the reliability of the results.

[0089] Data recording and analysis: The test data of each sample were summarized to compare the performance differences of Example 1 and each comparative example in terms of heat deformation temperature and thermal expansion coefficient.

[0090] Table 2: Thermal deformation temperature and thermal expansion coefficient test data According to Table 2 above, we can see that: In this experiment, thermal performance testing of the PCR-modified plastics of Example 1 and Comparative Examples 1 to 9 revealed that Example 1 exhibited significant advantages in terms of heat deformation temperature and thermal expansion coefficient. Combined with the design of the modified polycarbonate matrix, the experimental results demonstrated that the use of dynamically reversible chemical bonds significantly improved the thermal stability of the material. This chemical structure enables the material to effectively maintain its shape and strength under high-temperature conditions, thereby avoiding the performance degradation caused by thermal deformation. This mechanism is particularly suitable for applications requiring high-temperature use.

[0091] In addition, the innovative use of multilayered nano-functional fillers further enhances the thermal performance of the material. Experimental data show that in Example 1, the composite filling of aluminum nitride and polylactic acid not only improves the compatibility between the matrix and filler, but also forms a stable interface through the interaction between the filler and the matrix. This interface enhances the thermal conductivity of the material, allowing the heat applied to the material to be more evenly distributed, thereby improving the material's ability to resist thermal deformation. This phenomenon reflects the synergistic effect of the nanofiller and the modified polycarbonate matrix, further supporting the application of the present invention in thermal engineering materials.

[0092] Finally, the design concept of the enhanced toughening system provides strong support for the thermal performance of the material. Combining the characteristics of thermotropic liquid crystal polymers and polyester thermoplastic elastomers, this innovative combination not only increases the toughness of the material by constructing a microfiber network structure, but also slows down the propagation of cracks and the thermal expansion of the material under high temperature environments. This mechanism effectively improves the thermal stability and reliability of the material during actual use, thereby demonstrating the broad potential of Example 1 in high-performance applications. Overall, the experimental results highlight the importance of the present invention in providing materials with excellent thermal performance, ensuring reliability and applicability in a variety of application scenarios.

[0093] Experiment 3: Processing performance test Experimental Materials: The PCR modified plastic of Example 1; The PCR modified plastic of Comparative Example 1; The PCR modified plastic of Comparative Example 2; The PCR modified plastic of Comparative Example 3; The PCR modified plastic of Comparative Example 4; The PCR modified plastic of Comparative Example 5; The PCR modified plastic of Comparative Example 6; The PCR modified plastic of Comparative Example 7; The PCR modified plastic of Comparative Example 8; The PCR modified plastic of Comparative Example 9.

[0094] Experimental equipment: Melt flow index (MFI); Injection molding machine (for molding stability testing); Experimental steps: Melt index test: Place the PCR modified plastic sample to be tested into the hopper of the melt flow index instrument, ensuring that the sample volume meets the required standard.

[0095] The test temperature was set to 230°C and a load of 5 kg was applied.

[0096] Start the equipment and start timing, record the amount of melt flowing out of the mold, usually collect the outflow within 10 minutes.

[0097] The test was repeated at least twice to ensure the reliability of the data, and the melt index (MFI) value (unit: g / 10 min) was calculated.

[0098] Molding stability test: Each PCR-modified plastic was molded using an injection molding machine under the same process conditions, with injection pressure, speed, and cooling time set to ensure experimental consistency.

[0099] Observe whether there are defects (such as pores, warping, etc.) during each molding process, and record the appearance and pass rate of the molded parts.

[0100] Summarize the molding performance of each batch of materials, and finally record the number of qualified parts and the number of failed parts to evaluate the molding stability.

[0101] Data recording and analysis: The melt index and molding stability data of each sample were summarized, the differences in processing performance between Example 1 and each comparative example were compared, and the qualified rate and defect situation of molding stability were counted.

[0102] Table 3: Melt index and molding stability test data According to Table 3 above, we can see that: In this experiment, processing performance tests were conducted on the PCR-modified plastics of Example 1 and Comparative Examples 1 to 9. Example 1 demonstrated superior melt index and molding stability. The experimental results demonstrate that the dynamically reversible chemical bonds employed enable the material to maintain good fluidity during processing. This property enables Example 1 to more evenly fill the mold during injection molding and effectively reduces bubbles and defects during the molding process, thereby improving the molding yield.

[0103] In addition, the innovative multi-layer nano-functional filler design significantly improves the material's fluidity and processing stability. In Example 1, the composite filling of aluminum nitride and polylactic acid enhances the interaction between the matrix and the filler to form a stable physical network structure, thereby improving the fluidity of the polymer in the molten state. Better fluidity means that the material can be dispersed quickly and evenly at high temperatures, thereby optimizing the injection molding process and improving production efficiency. This improvement supports the application of the material in complex and demanding production environments and significantly improves the stability of the production process.

[0104] Finally, the enhanced toughening system design provides a potential mechanism for strain dispersion during processing. By combining a thermotropic liquid crystal polymer with a polyester thermoplastic elastomer, not only is the fracture toughness of the material enhanced, but stress concentration is also effectively suppressed during processing. This diversified dispersion effect effectively reduces molding defects caused by stress concentration, thereby improving the overall processing performance of the material.

[0105] Therefore, the high processing performance of Example 1 reflects the synergistic effect of various innovations, ensuring the superiority and feasibility of the material in practical applications. Overall, the experimental results emphasize the potential value of this invention in industrial production and its importance in improving material performance and processing efficiency.

[0106] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A PCR modified plastic used in a barcode scanner, characterized in that: It includes the following components, in parts by weight: 65-88 parts of a modified polycarbonate matrix, the modified polycarbonate matrix being prepared by reacting 100 parts of post-consumer recycled polycarbonate with 0.5-7 parts of a polymer modifier, the polymer modifier being used to form a topological network comprising dynamically reversible chemical bonds in the polycarbonate; 3-15 parts of a multilayer nano-functional filler, wherein the nano-functional filler comprises: a nano-core, a polymer shell layer covering the surface of the core, and a functionalized molecular halo region formed outside the shell layer; 5-15 reinforcement and toughening system, comprising 1-5 parts of a polymer capable of forming an in-situ microfiber network in the modified polycarbonate matrix, and 3-10 parts of a thermoplastic elastomer, wherein the thermoplastic elastomer is orderly distributed within the confined space formed by the microfiber network; 5-3 parts additives.

2. The PCR modified plastic for use in a barcode scanner according to claim 1, wherein: The polymer modifier is a bisoxazoline-terminated oligosiloxane.

3. The PCR modified plastic for use in a barcode scanner according to claim 1, wherein: The nano core of the multilayered nano-functional filler is nano-aluminum nitride or nano-diamond with a chemically treated surface; the polymer shell is a gradient modulus polymer layer formed on the surface of the core by in-situ polymerization; and the functionalized molecular halo region contains fluorine-containing polymer segments or segments that can interact with the dynamic reversible chemical bonds in the modified polycarbonate matrix.

4. The PCR modified plastic for use in a barcode scanner according to claim 1, wherein: The polymer that forms the microfiber network in situ in the modified polycarbonate matrix is ​​a thermotropic liquid crystal polymer; and the thermoplastic elastomer is a polyester thermoplastic elastomer.

5. A method for preparing a PCR-modified plastic for use in a barcode scanner, for preparing the PCR-modified plastic for use in a barcode scanner according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: melt-reacting and extruding post-consumer recycled polycarbonate and a polymer modifier in a first reaction extrusion device to obtain a modified polycarbonate masterbatch containing a dynamic reversible chemical bond topology network precursor; Step 2: melt-blending the modified polycarbonate masterbatch obtained in step 1 with other components in a second blending and extrusion device to obtain a PCR modified plastic composition.

6. The method for preparing a PCR-modified plastic for use in a barcode scanner according to claim 5, wherein: The temperature of the reaction zone of the first stage melt reaction extrusion in step 1 is 230-270° C., and the screw speed is 100-350 rpm.

7. The method for preparing a PCR-modified plastic for use in a barcode scanner according to claim 5, wherein: The components in step 2 include multilayer nano-functional fillers, polymers capable of forming an in-situ microfiber network in a modified polycarbonate matrix, thermoplastic elastomers and additives, wherein the nano-functional fillers are dispersed at the nanoscale, the polymer forms an in-situ microfiber network, and the thermoplastic elastomer is distributed in an orderly manner in the microfiber network.

8. The method for preparing a PCR-modified plastic for use in a barcode scanner according to claim 5, wherein: The second stage of precision melt blending and structure control extrusion in step 2 adopts a segmented feeding method, and the modified PCR-PC masterbatch is added in sequence, and then the multi-layer structure nano-functional filler, the polymer capable of forming a microfiber network in situ in the modified polycarbonate matrix and the thermoplastic elastomer are added at different positions downstream.

9. The method for preparing a PCR-modified plastic for use in a barcode scanner according to claim 5, wherein: Prior to step 2, a multilayered nano-functional filler is prepared by surface activating the nano-core, in-situ polymerizing and coating the activated core surface with a polymer shell, and constructing a functionalized molecular halo region outside the shell.

10. The method for preparing a PCR-modified plastic for use in a barcode scanner according to claim 5, wherein: In the step 2, the second blending and extrusion equipment is provided with at least two stages of vacuum exhaust ports, and the operating vacuum degree is 0.08-0.098 MPa.

Images