Preparation method of PC-loaded chain extender master batch and application of PC-loaded chain extender master batch in PC composite material

Abstract

The application discloses a preparation method of PC-loaded chain extender masterbatch and application of the PC-loaded chain extender masterbatch in PC composite materials. A chain extension copolymer prepared by taking glycidyl methacrylate (GMA), methyl acrylate (MA) and methyl methacrylate (MMA) as raw materials is mixed with a PC solution, and the PC-loaded chain extender masterbatch is prepared through a common precipitation method. In the chain extension copolymer, the addition amount of GMA is 2-30 wt% of the addition amount of MMA, the addition amount of MA is 2-15 wt% of the addition amount of MMA, and the addition amount of MMA is 3-20 wt% of the addition amount of a solvent. The mass of the PC solution and MMA in the chain extension copolymer is 10-300% of the mass of polycarbonate. The PC-loaded chain extender masterbatch prepared through the above scheme can be directly used for the preparation of PC composite materials through a melt blending method. The prepared PC composite materials have good solvent resistance, small color change, good transparency and excellent physical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a PC-loaded chain extender masterbatch and its application in PC composite materials. Background Technology

[0002] Polycarbonate (PC) is a thermoplastic containing (ORO-CO) chain segments in its main chain. It possesses excellent mechanical properties, along with good heat resistance and flame retardancy. Since entering the market in the 1960s, PC has been widely used in electrical appliances, machinery, electronics, automobiles, instruments, aerospace, and household applications. While PC exhibits excellent mechanical, thermal, and optical properties, its relatively poor solvent resistance has hindered its further application in various fields. Mechanistically, the presence of numerous ester groups in PC molecules makes them susceptible to hydrolysis or alcoholysis in certain environments, leading to structural damage. Furthermore, the abundant benzene rings and polar groups in PC result in rigid molecular chains, causing PC molecules to tend to form irregular, long, and rigid fibrillary bundles. These interwoven bundles form a loose network, resulting in numerous micropores in the secondary structure of PC, making it easier for various solvents to penetrate the material's interior. Common solvents such as methanol, ethanol, isopropanol, acetic acid, benzene, and chlorobenzene can cause significant swelling or even dissolution of PC materials, which can reduce the mechanical properties of the product and further lead to cracks or stress cracking.

[0003] Solvent resistance of PC is improved through composite modification, meeting the market's comprehensive requirements for cost, performance, and subsequent processing of PC-related materials. This is currently the main method for developing solvent-resistant PC. Mechanistically, aromatic acid-saturated polyesters have flexible -CH2-CH2- segments, sterically hindered benzene ring structures, and polar ester groups in their molecular chains. The benzene ring and ester groups form a conjugated system, resulting in greater steric hindrance during chain rotation and a straight-chain configuration. The benzene rings are in the same plane within the molecular chain, leading to high geometric and chemical regularity. Therefore, aromatic acid-saturated polyesters contain numerous crystalline regions and exhibit excellent crystallinity. This structural characteristic endows them with a high glass transition temperature and outstanding chemical resistance. Melt blending aromatic acid-saturated polyesters with PC effectively utilizes the structural characteristics of the polyesters to compensate for the numerous microvoids in the secondary structure of PC, forming a PC composite material with good solvent resistance and stress cracking resistance.

[0004] However, PC is a non-crystalline polymer, while aromatic acid-saturated polyesters are generally semi-crystalline polymers. Their poor compatibility makes it difficult to fully realize their performance advantages through direct blending. More importantly, the introduction of aromatic acid-saturated polyesters compromises the transparency of PC materials. To maintain transparency, achieve performance close to conventional PC materials, and fully leverage the role of aromatic acid-saturated polyesters in improving PC's solvent resistance, adding reactive interface modifiers to PC composites is crucial. Both aromatic acid-saturated polyesters and PC possess carboxyl groups. When a designed interface modifier reacts with these carboxyl groups under certain conditions, the bonding between PC and aromatic acid-saturated polyesters is strengthened. This allows the aromatic acid-saturated polyesters to effectively compensate for the PC's susceptibility to organic solvent erosion, suppresses the crystallinity of the aromatic acid-saturated polyesters, and maintains the transparency of the PC composite.

[0005] Currently, acrylate chain extenders with epoxy groups can effectively combine PC and aromatic acid-saturated polyester phases in PC composites. However, existing acrylate chain extenders are not specifically designed for PC composites and suffer from insufficient efficiency, failing to significantly improve the solvent resistance of the composite material. More importantly, since the chain extender needs to be added separately to the PC composite as an additive, stronger shear mixing is required during processing to ensure its full dispersion and bonding within the system. However, excessive shear mixing leads to significant yellowing of the PC, affecting the material's appearance.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing PC-loaded chain extender masterbatch to address the problems in the prior art. The method involves mixing a chain extender copolymer prepared from glycidyl methacrylate (GMA), methyl acrylate (MA), and methyl methacrylate (MMA) with a PC solution, and then precipitating the copolymer to obtain the PC-loaded chain extender masterbatch. This method can effectively improve the solvent resistance of PC composite materials without affecting the transparency of the PC itself.

[0008] Another objective of this invention is to provide an application of the PC-loaded chain extender masterbatch prepared by the above method in PC composite materials. The PC-loaded chain extender masterbatch is blended with other raw materials and then directly obtained by melt extrusion. The PC composite material prepared by the above scheme has good solvent resistance, small color change, good transparency, and excellent physical properties.

[0009] To achieve the above objectives, the first aspect of the present invention provides a method for preparing PC-loaded chain extender masterbatch, comprising the following steps:

[0010] S1. A chain-extended copolymer was prepared using glycidyl methacrylate, methyl acrylate and methyl methacrylate as raw materials;

[0011] S2. The chain extender masterbatch is prepared by mixing the chain extender copolymer and polycarbonate solution and then precipitating them together.

[0012] Further, in step S1, glycidyl methacrylate, methyl acrylate, methyl methacrylate and solvent are added to the reactor, heated to 60-80°C under a protective atmosphere, and then an initiator is added. The mixture is stirred under a protective atmosphere to obtain the chain-extended copolymer.

[0013] Preferably, the solvent is at least one of tetrahydrofuran, N,N-dimethylformamide, and chloroform.

[0014] Preferably, the solvent is tetrahydrofuran.

[0015] Furthermore, after heating to 60-80℃ under a protective atmosphere and maintaining the temperature for 30-60 minutes under a protective atmosphere, an initiator is added;

[0016] The amount of initiator used is 0.1 wt% of the sum of the amounts of glycidyl methacrylate, methyl acrylate and methyl methacrylate added;

[0017] After adding the initiator, the reaction was stirred continuously for 6-12 hours to obtain the chain-extended copolymer.

[0018] Preferably, the initiator is selected from at least one of azobisisobutyronitrile (AIBN) and azobisisoheptanenitrile (ABVN).

[0019] Furthermore, the amount of glycidyl methacrylate added is 2-30 wt% of the amount of methyl methacrylate added;

[0020] The amount of methyl acrylate added is 2-15 wt% of the amount of methyl methacrylate added;

[0021] The amount of methyl methacrylate added is 3-20 wt% of the amount of solvent added.

[0022] Preferably, the amount of glycidyl methacrylate added is 4-12 wt% of the amount of methyl methacrylate added.

[0023] In the above scheme, by adjusting the amounts of glycidyl methacrylate, methyl acrylate, and methyl methacrylate, the structure of the chain extender can be controlled, thereby improving its application range. Among them, glycidyl methacrylate, as an active component that can react with the carboxyl groups in PC and aromatic acid saturated polyester, can ensure the efficiency of the chain extender while avoiding excessive cross-linking in the PC composite material during actual use by adjusting the proportion of glycidyl methacrylate.

[0024] Furthermore, in step S2, the polycarbonate content in the polycarbonate solution is 5-25 wt%.

[0025] Furthermore, polycarbonate particles are dissolved in an organic solvent to prepare a polycarbonate solution;

[0026] The selected polycarbonate has a melt index of 2-30 g / 10 min under conditions of 300℃ and 1.2 kg load. This melt index range covers the most common types of polycarbonate, thus limiting the polycarbonate carrier of the masterbatch and ensuring that the prepared masterbatch has good versatility and can be adapted to the vast majority of polycarbonate composite materials.

[0027] Furthermore, in the mixture of chain extender copolymer and polycarbonate solution, the mass of methyl methacrylate is 10-300% of the mass of polycarbonate.

[0028] The above scheme can control the chain extender component in PC-loaded chain extender masterbatch by adjusting and controlling the proportion of methyl methacrylate in the chain extender copolymer.

[0029] Furthermore, in step S2, the precipitant is added to the mixture of chain extender copolymer and polycarbonate solution, and the mixture is stirred continuously to allow polycarbonate and chain extender copolymer to precipitate together. The precipitated precipitate is filtered and then washed with the precipitant and dried to obtain PC-loaded chain extender masterbatch.

[0030] The precipitant is a small molecule alcohol.

[0031] The preferred precipitant is one or more of methanol, ethanol, n-propanol, and isopropanol.

[0032] Preferably, the stirring speed is 500-2000 rpm.

[0033] Furthermore, the washing process using a precipitant is repeated three times.

[0034] Furthermore, the precipitate washed with the precipitant is dried at a temperature of 60-100℃ for 10-16 hours to obtain PC-loaded chain extender masterbatch.

[0035] In the above scheme, after the chain extender copolymer and polycarbonate are thoroughly mixed in the solution, they exhibit a uniform distribution. Adding a precipitant at this point allows the polycarbonate to precipitate immediately, while the chain extender is encapsulated within the polycarbonate, maintaining its uniform distribution within the polycarbonate carrier. Compared to traditional methods such as mechanical blending, the method of achieving uniform mixing in solution followed by precipitation better achieves uniform dispersion of the chain extender within the polycarbonate carrier. Simultaneously, the polycarbonate molecular chains are protected to the greatest extent, avoiding aging and damage during shearing processes.

[0036] The second aspect of the present invention provides the application of the PC-loaded chain extender masterbatch prepared by the above preparation method in PC composite materials, characterized in that the PC-loaded chain extender masterbatch is blended with the raw materials for preparing PC composite materials and then directly melt-extruded to obtain PC composite materials.

[0037] The specific steps are as follows:

[0038] (1) Mixing raw materials:

[0039] PC, PC-loaded chain extender masterbatch, antioxidant, and aromatic acid saturated polyester are added to a high-speed mixer in the following proportions: PC 1-99 wt%, aromatic acid saturated polyester 0.4-70 wt%, PC-loaded chain extender masterbatch 0.4-60 wt%, and antioxidant 0.2-1 wt%. The mixture is then mixed to obtain a composite material.

[0040] The aromatic acid saturated polyester is one or more of polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate-1,4-cyclohexanediol ester; the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 626.

[0041] (2) Blending extrusion:

[0042] A twin-screw extruder with a length-to-diameter ratio of 40 to 48:1 was selected. The vacuum extraction pressure in the metering section was set to -0.85 to -0.95 MPa, the temperature of each section of the screw was set in the range of 150 to 260℃, and the main machine speed was set to 300 to 500 rpm. The mixed material was added to the twin-screw extruder through the main feed port for melt extrusion, and after pelleting, the corresponding PC composite material was obtained.

[0043] In the above scheme, the chain extender molecular chain contains GMA component, and the epoxy group can react with the carboxyl and hydroxyl groups present in the PC and aromatic acid saturated polyester molecular chains, thereby promoting the combination of the two, so that the aromatic acid saturated polyester can more effectively make up for the large number of micro-voids in the secondary structure of PC and exert its solvent erosion resistance characteristics.

[0044] Meanwhile, the movement ability of aromatic acid saturated polyester is restricted and its movement speed is slowed down after the addition of chain extenders. In addition, its crystallization rate is relatively slow. Therefore, the crystallinity of aromatic acid saturated polyester in PC composite material decreases, and the material is closer to the amorphous state of pure PC, thus maintaining the transparency of composite material.

[0045] In addition, since the chain extender obtained by synthesis is fully mixed with PC in solution and co-precipitates out, the process of blending chain extender with PC is basically completed. Therefore, when preparing PC composite materials using PC-loaded chain extender masterbatch, the shear dispersion effect of the external environment needs to be greatly reduced, and the problem of PC yellowing caused by long-term strong shear is also alleviated.

[0046] The advantages of this invention are:

[0047] 1. The preparation method of the PC-loaded chain extender masterbatch provided by the present invention is simple, easy to control and achieve large-scale production; it can adjust the proportion of each component in the chain extender copolymer and the ratio of the chain extender copolymer to the PC solution in a targeted manner according to actual use requirements, so as to obtain a PC-loaded chain extender masterbatch that better meets the production needs.

[0048] 2. Applying the PC-loaded chain extender prepared by the method of the present invention to the preparation of PC composite materials can effectively improve the solvent resistance of PC composite materials without affecting the transparency of PC itself or the physical properties of the material.

[0049] 3. The PC-loaded chain extender masterbatch prepared by the method described in this invention can be directly applied to the preparation process of PC composite materials through melt blending. Compared with the existing PC composite material preparation process, the process is simpler and less time-consuming. Furthermore, the low-shear melt blending process is beneficial to the preservation of the physical properties of PC materials, avoids yellowing of materials caused by long-term, high-shear processes, and improves the quality of PC composite materials. Detailed Implementation

[0050] Exemplary embodiments of the present invention will be described in more detail below. Those skilled in the art will understand that the following embodiments are only used to explain and illustrate the technical principles, features and advantages of the present invention in more detail, and are not intended to limit the scope of protection of the present invention.

[0051] The present invention will now be described in detail with reference to specific embodiments.

[0052] Example 1

[0053] As an embodiment of the present invention, this embodiment provides a method for preparing PC-loaded chain extender masterbatch, as detailed below:

[0054] Weigh 1000g of tetrahydrofuran, 200g of MMA, 4g of MA, and 4g of GMA and add them to a reaction vessel equipped with a stirrer, thermometer, and reflux condenser. Adjust the reaction temperature to 60℃, purge with nitrogen for 30 min, then add 0.208g of AIBN. Continue the reaction under nitrogen protection and stirring at 2000 rpm for 12 h to obtain the chain-extended copolymer, which contains 2wt% GMA.

[0055] Take 480g of PC (grade 1609) produced by Luxi Chemical Institute and dissolve it in 960g of dichloroethane at room temperature in a 3L three-necked flask equipped with mechanical stirring and ultrasonic equipment to prepare a solution. Put the solution into a 2L three-necked flask equipped with mechanical stirring, adjust the temperature to 20℃, and stir at 2000rpm. Add the chain extender copolymer to the flask containing the PC solution and continue stirring for 20min. At this time, the mass of MMA component is 250wt% of the mass of PC.

[0056] Then, 200 ml of anhydrous ethanol was added dropwise to a 2 L three-necked flask at room temperature at a rate of 20 ml / min. During the addition, the three-necked flask was stirred at a speed of 2000 rpm, and PC and chain extender were precipitated together. The precipitated precipitate was taken and washed three times with anhydrous ethanol. Then, it was vacuum dried at 60 °C for 16 h to obtain PC-loaded chain extender masterbatch.

[0057] Example 2

[0058] As an embodiment of the present invention, this embodiment provides a method for preparing PC-loaded chain extender masterbatch, as detailed below:

[0059] 20 kg of tetrahydrofuran, 1 kg of MMA, 150 g of MA, and 80 g of GMA were weighed and added to a reaction vessel equipped with a stirrer, thermometer, and reflux condenser. The reaction temperature was adjusted to 80 °C, and nitrogen gas was purged for 60 min. Then, 1.23 g of AIBN was added, and the reaction was continued for 6 h under nitrogen protection and stirring at 500 rpm to obtain a chain-extended copolymer with a GMA content of 8 wt%.

[0060] Take 10 kg of PC of grade SC-1100R produced by Samsung Corporation and dissolve it in 100 kg of dichloroethane at room temperature in a reactor equipped with mechanical stirring and ultrasound to prepare a solution. Adjust the temperature to 40°C and stir at 500 rpm. Add the chain extender copolymer to the reactor and continue stirring for 80 min. At this time, the mass of MMA component is 10 wt% of the mass of PC.

[0061] Then, 2000 ml of anhydrous methanol was added dropwise to the reaction vessel at a rate of 20 ml / min at room temperature. During the addition, the mixture was stirred at a rate of 500 rpm. PC and chain extender precipitated together. The precipitated precipitate was collected and washed three times with anhydrous methanol. Then, it was vacuum dried at 100 °C for 10 h to obtain PC-loaded chain extender masterbatch.

[0062] Example 3

[0063] As an embodiment of the present invention, this embodiment provides a method for preparing PC-loaded chain extender masterbatch, as detailed below:

[0064] 10 kg of tetrahydrofuran, 1 kg of MMA, 80 g of MA, and 100 g of GMA were weighed and added to a reaction vessel equipped with a stirrer, thermometer, and reflux condenser. The reaction temperature was adjusted to 70 °C, and nitrogen gas was purged for 40 min. Then, 1.18 g of AIBN was added, and the reaction was continued for 10 h under nitrogen protection and stirring speed of 1000 rpm to obtain a chain-extended copolymer with a GMA content of 10 wt%.

[0065] Take 1 kg of PC (CLARNATE2100) produced by Yantai Wanhua and dissolve it in 10 kg of trichloroethane at room temperature in a reactor equipped with mechanical stirring and ultrasound to prepare a solution. Adjust the temperature to 30°C and stir at 1000 rpm. Add the chain extender copolymer to the reactor and continue stirring for 60 min. At this time, the mass of MMA component is 100 wt% of the mass of PC.

[0066] Then, 400 ml of anhydrous n-propanol was added dropwise to the reactor at a rate of 20 ml / min at room temperature. During the addition, the mixture was stirred at a rate of 1000 rpm. PC and chain extender precipitated together. The precipitate was collected and washed three times with anhydrous n-propanol. Then, it was vacuum dried at 80 °C for 13 h to obtain PC-loaded chain extender masterbatch.

[0067] Example 4

[0068] As an embodiment of the present invention, this embodiment provides a method for preparing PC-loaded chain extender masterbatch, as detailed below:

[0069] 12 kg of tetrahydrofuran, 1.5 kg of MMA, 80 g of MA, and 150 g of GMA were weighed and added to a reaction vessel equipped with a stirrer, thermometer, and reflux condenser. The reaction temperature was adjusted to 70 °C, and nitrogen gas was purged for 50 min. Then, 1.73 g of AIBN was added, and the reaction was continued for 8 h under nitrogen protection and stirring speed of 1500 rpm to obtain a chain-extended copolymer with a GMA content of 10 wt%.

[0070] Take 1 kg of PC (CLARNATE2100) produced by Yantai Wanhua and dissolve it in 7 kg of chloroform at room temperature in a reactor equipped with mechanical stirring and ultrasound to prepare a solution. Adjust the temperature to 30°C and stir at 1500 rpm. Add the chain extender copolymer to the reactor and continue stirring for 50 min. At this time, the mass of MMA component is 150 wt% of the mass of PC.

[0071] Then, 600 ml of anhydrous methanol was added dropwise to the reaction vessel at a rate of 20 ml / min at room temperature. During the addition, the mixture was stirred at a rate of 1500 rpm. PC and the chain extender precipitated together. The precipitate was collected and washed three times with anhydrous methanol. Then, it was vacuum dried at 90 °C for 11 h to obtain PC-loaded chain extender masterbatch.

[0072] Examples 5 to 9

[0073] The following examples are based on Example 1, with only the content of GMA in the chain extender copolymer and the corresponding amount of catalyst added being changed, as shown in the table below:

[0074] It should be noted that the GMA content in the table below refers to the content obtained by comparing the amount of methyl methacrylate added in the chain extender copolymer with this benchmark.

[0075] GMA content (wt%) GMA addition (g) AIBN addition (g) Example One 2 4 0.208 Example Five 4 8 0.212 Example Six 8 16 0.22 Example Seven 12 24 0.228 Example Eight 20 40 0.244 Example Nine 30 60 0.264

[0076] Examples 10 to 13

[0077] The following examples are based on Example 2, with only the content of MA relative to MMA in the chain extender copolymer and the corresponding amount of catalyst added being changed, as shown in the table below:

[0078] It should be noted that the MA content in the table below refers to the content obtained by comparing the amount of methyl methacrylate added in the chain extender copolymer with this benchmark.

[0079]

[0080]

[0081] The present invention also provides the application of PC-loaded chain extender masterbatch in PC composite materials, which will be further described below with specific embodiments.

[0082] Examples 14 to 19

[0083] As another embodiment of the present invention, this embodiment provides the application of the PC-loaded chain extender masterbatch prepared by the preparation method described in Example 2 in PC composite materials, as detailed below.

[0084] PC, polyethylene terephthalate, PC-loaded chain extender masterbatch prepared by the method described in Example 2, and antioxidant were mixed in a certain proportion. A twin-screw extruder with a length-to-diameter ratio of 40:1 (equipped with a weak shear screw combination, having one set of kneading blocks and two sets of 90-degree and 45-degree screw elements) was selected. The vacuum extraction pressure of the metering section was set to -0.95 MPa, the temperature of each section of the screw was set in the range of 150-260°C, and the main machine speed was set to 500 rpm. The mixture was added to the twin-screw extruder through the main feed port for melt extrusion, and after pelleting, PC composite material was obtained.

[0085] The specific proportions of the raw materials are shown in the table below:

[0086]

[0087]

[0088] Example 20

[0089] As another embodiment of the present invention, this embodiment provides the application of the PC-loaded chain extender masterbatch prepared by the preparation method described in Example 3 in PC composite materials, as detailed below.

[0090] 70 parts of PC (Yantai Wanhua CLARNATE 2100), 19.5 parts of polybutylene terephthalate, 10 parts of PC-loaded chain extender masterbatch prepared as described in Example 3, 0.2 parts of antioxidant 1076, and 0.3 parts of antioxidant 626 were added to a high-speed mixer and mixed for 5 minutes to obtain a mixed material containing chain extender masterbatch.

[0091] A twin-screw extruder with a length-to-diameter ratio of 48:1 (equipped with a weak-shear screw combination, featuring one set of kneading blocks and two sets of 90-degree and 45-degree screw elements) was selected. The vacuum extraction pressure in the metering section was set to -0.85 MPa, the temperature of each section of the screw was set in the range of 150–260°C, and the main extruder speed was set to 300 rpm. The mixed material was fed into the twin-screw extruder through the main feed port for melt extrusion, and then pelletized to obtain PC composite material.

[0092] Example 21

[0093] As another embodiment of the present invention, this embodiment provides the application of the PC-loaded chain extender masterbatch prepared by the preparation method described in Example 4 in PC composite materials, as detailed below.

[0094] 94 parts of PC (Yantai Wanhua CLARNATE 2100), 2.5 parts of polybutylene terephthalate, 3 parts of PC-loaded chain extender masterbatch prepared as described in Example 4, 0.2 parts of antioxidant 1076, and 0.3 parts of antioxidant 626 were added to a high-speed mixer and mixed for 5 minutes to obtain a mixed material containing the chain extender masterbatch. A twin-screw extruder with a length-to-diameter ratio of 48:1 (equipped with a weak-shear screw combination, featuring one set of kneading blocks and two sets of 90-degree and 45-degree screw elements) was selected. The vacuum extraction pressure in the metering section was set to -0.9 MPa, the temperature of each section of the screw was set in the range of 150–260°C, and the main extruder speed was set to 400 rpm. The mixed material was sequentially fed into the twin-screw extruder through the main feed port for melt extrusion. After pelleting, the PC composite material using the chain extender masterbatch was obtained.

[0095] The following is a comparative test of the performance of the PC-loaded chain extender masterbatch prepared by the method described in this invention, and the PC composite material prepared using chain extender masterbatches with different PC loads, using specific experimental examples.

[0096] Experimental Example 1

[0097] As an experimental example of the present invention, this experimental example tests PC-loaded chain extender masterbatches with different GMA contents prepared by the preparation method described in Example 1, as follows:

[0098] 25 parts of PC (Luxi Chemical 1609), 70 parts of polybutylene terephthalate, 4.7 parts of PC-loaded chain extender masterbatch prepared according to the method described in Example 1, 0.1 parts of antioxidant 1076, and 0.2 parts of antioxidant 168 were mixed and added to a high-speed mixer and mixed for 5 minutes. The torque change during material mixing was tested in a Hacker torque rheometer at 250°C and a rotor speed of 60 rpm. The test results are shown in the table below.

[0099] It should be noted that the GMA content in the table below refers to the content obtained by comparing the amount of methyl methacrylate added in the chain extender copolymer with this benchmark.

[0100]

[0101]

[0102] It should be noted that the GMA content in Comparative Example 1 in the table above is 0%. It is actually a mixed material without chain extender masterbatch prepared by using 29.7 parts of PC, 70 parts of polybutylene terephthalate, 0.1 parts of antioxidant 1076, and 0.2 parts of antioxidant 168. It was also mixed in a high-speed mixer for 5 minutes and then tested using a Hacker torque rheometer.

[0103] As can be seen from the table above, the equilibrium torque of the material gradually increases with the increase of GMA content in the chain extender. This indicates that PC and GMA are combined under the action of the chain extender, thus demonstrating the effectiveness of chain extension. Furthermore, it can be seen that when the GMA content is less than 4%, the torque value decreases significantly, and the improvement is small compared with the chain extender masterbatch without PC loading. When the GMA content is higher than 12%, although the torque value still increases, the increase is not significant compared with the increase in GMA content. Therefore, it can be concluded from the table above that the preferred GMA content is 4-12 wt%.

[0104] Experimental Example 2

[0105] As another experimental example of the present invention, this experimental example tests the PC composite material described in Examples 14 to 19. Specifically, the melt index of the PC composite material is determined using a melt indexer at 250°C and 2.16 kg. The results are as follows:

[0106]

[0107]

[0108] As can be seen from the table above, the melt index of the material gradually decreases as the amount of chain extender masterbatch increases. This means that PC and polybutylene terephthalate are bonded together under the action of the chain extender, thereby increasing the viscosity of the material. This further confirms the effectiveness of the chain extender prepared in this invention.

[0109] Experiment Example 3

[0110] As another experimental example of the present invention, the solvent resistance of the PC composite material as described in Example 20 and the PC composite material prepared without chain extender were tested. Specifically, after the PC composite material was injection molded into a sample, it was immersed in organic solvents such as carbon tetrachloride, methanol, and acetic acid. After 72 hours, the sample was taken out and the corrosion of the sample was compared. The comparison results are shown in the table below:

[0111]

[0112] It should be noted that Comparative Example 2 in the table above is a PC mixture without chain extender masterbatch obtained by mixing 80 parts of PC (Yantai Wanhua CLARNATE 2100), 19.5 parts of polybutylene terephthalate, 0.2 parts of antioxidant 1076, and 0.3 parts of antioxidant 626 in a high-speed mixer for 5 minutes. The mixture was then tested in different solvents.

[0113] As can be seen from the table above, the PC composite material prepared with PC-loaded chain extender masterbatch in Example 20 has significantly improved solvent resistance compared with the PC composite material prepared without PC-loaded chain extender masterbatch.

[0114] Experiment Example 4

[0115] As another experimental example of the present invention, the performance of the PC composite material as described in Example 21 and the PC composite material prepared with a commercially available chain extender were tested. Specifically, after the PC composite material was injection molded into a sample, its color difference value, transparency, basic mechanical properties, etc. were tested. The test results are shown in the table below:

[0116]

[0117] It should be noted that Comparative Examples 3 and 4 in the above schemes are the results obtained by testing PC composite materials prepared with commercially available chain extenders under different shear strengths. The specific preparation process is as follows: 95.2 parts of PC (Yantai Wanhua CLARNATE 2100), 2.5 parts of polybutylene terephthalate, 1.8 parts of commercially available chain extender GP301, 0.2 parts of antioxidant 1076, and 0.3 parts of antioxidant 626 are mixed to form a composite material. The mixture is also mixed for 5 minutes using a high-speed mixer to obtain the composite material using commercially available chain extenders. Twin-screw extruders with a length-to-diameter ratio of 48:1, equipped with either a weak-shear screw combination (with one set of kneading blocks and two sets of 90-degree and 45-degree screw elements) or a strong-shear screw combination (with three sets of kneading blocks and five sets of 90-degree and 45-degree screw elements), were used for melt extrusion. The vacuum extraction pressure in the metering section of the extruder was set to -0.9 MPa, the temperature of each section of the screw was set in the range of 150–260°C, and the main engine speed was set to 400 rpm. After pelleting, two types of PC composite materials using commercially available chain extenders were obtained.

[0118] Comparative Example 3 shows the test results of PC composite material extruded under strong shear, and Comparative Example 4 shows the test results of PC composite material extruded under weak shear.

[0119] As can be seen from the table, the chain extender masterbatch prepared by the present invention can achieve full dispersion of the chain extender in the material when the extruder is equipped with a weak shear screw combination, thereby preparing PC composite materials with good transparency, low yellowing, and excellent physical properties and solvent resistance.

[0120] Experimental Example 5

[0121] As an experimental example of the present invention, this experimental example uses PC-loaded chain extender masterbatches with different MA contents prepared as in Examples 2, 10 to 13 to prepare PC composite materials, and tests the properties of the PC composite materials as follows:

[0122] 70 parts of PC (SC-1100R), 9.7 parts of polybutylene terephthalate, 20 parts of PC-loaded chain extender masterbatch prepared by the method described in Example 2, 0.1 parts of antioxidant 1076, and 0.2 parts of antioxidant 168 were mixed and added to a high-speed mixer and mixed for 5 minutes.

[0123] A twin-screw extruder with a length-to-diameter ratio of 40:1 (equipped with a weak-shear screw combination, featuring one set of kneading blocks and two sets of 90-degree and 45-degree screw elements) was selected. The vacuum extraction pressure in the metering section was set to -0.95 MPa, the temperature of each screw section was set within the range of 150–260℃, and the main extruder speed was set to 500 rpm. The mixture was fed into the twin-screw extruder through the main feed port for melt extrusion, and then pelletized to obtain PC composite material. After injection molding the PC composite material into samples, its basic mechanical properties and melt flow index (250℃, 2.16 kg) were tested. The test results are shown in the table below.

[0124] It should be noted that the MA content in the table below refers to the content obtained by comparing the amount of methyl methacrylate added in the chain extender copolymer with this benchmark.

[0125]

[0126] As shown in the table above, with the increase of MA content in the chain extender, the melt index of the material decreases slightly, the notched impact strength gradually decreases, while the flexural strength gradually increases. Based on the above trends in performance changes, the MA content in the chain extender structure can be specifically designed according to the requirements of the final material properties, thereby achieving targeted adjustment of the properties of the prepared PC composite material.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing PC-loaded chain extender masterbatch, characterized in that, Includes the following steps: S1. Glycidyl methacrylate, methyl acrylate, methyl methacrylate and solvent are added to a reactor, heated to 60-80℃ under a protective atmosphere and maintained at the temperature for 30-60 min under a protective atmosphere, then an initiator is added and stirred under a protective atmosphere to obtain a chain-extended copolymer. The initiator is selected from at least one of azobisisobutyronitrile and azobisisoheptanenitrile; The amount of glycidyl methacrylate added is 4-12 wt% of the amount of methyl methacrylate added; The amount of methyl acrylate added is 2-15 wt% of the amount of methyl methacrylate added; The amount of methyl methacrylate added is 3-20 wt% of the amount of solvent added; S2. Mix the chain extender copolymer and polycarbonate solution, add the precipitant to the mixture, and continue stirring to allow the polycarbonate and chain extender copolymer to precipitate together. Filter the precipitate, wash it with the precipitant, and dry it to obtain PC-loaded chain extender masterbatch; wherein, The polycarbonate content in the polycarbonate solution is 5-25 wt%. In the mixture of chain extender copolymer and polycarbonate solution, the mass of methyl methacrylate is 10-300% of the mass of polycarbonate; The precipitant is one or more of methanol, ethanol, n-propanol, and isopropanol.

2. The method for preparing PC-loaded chain extender masterbatch according to claim 1, characterized in that, The solvent is at least one of tetrahydrofuran, N,N-dimethylformamide, and chloroform.

3. The method for preparing PC-loaded chain extender masterbatch according to claim 2, characterized in that, The solvent is tetrahydrofuran.

4. The method for preparing PC-loaded chain extender masterbatch according to claim 1, characterized in that, The amount of initiator used is 0.1 wt% of the sum of the amounts of glycidyl methacrylate, methyl acrylate and methyl methacrylate added; After adding the initiator, the reaction was stirred continuously for 6-12 hours to obtain the chain-extended copolymer.

5. The method for preparing PC-loaded chain extender masterbatch according to any one of claims 1-4, characterized in that, A polycarbonate solution is prepared by dissolving polycarbonate particles in an organic solvent; The selected polycarbonate is a polycarbonate with a melt index of 2-30 g / 10 min under the conditions of 300℃ and 1.2 kg load.

6. The method for preparing PC-loaded chain extender masterbatch according to any one of claims 1-4, characterized in that, In step S2, the stirring speed is 500-2000 rpm.

7. The method for preparing PC-loaded chain extender masterbatch according to any one of claims 1-4, characterized in that, The washing process using a precipitant was repeated three times.

8. The method for preparing PC-loaded chain extender masterbatch according to any one of claims 1-4, characterized in that, The precipitate washed with the precipitant was dried at a temperature of 60-100℃ for 10-16 hours to obtain PC-loaded chain extender masterbatch.

9. The application of a PC-loaded chain extender masterbatch prepared by any one of the preparation methods described in claims 1-8 in the preparation of solvent-resistant, transparent PC composite materials, characterized in that, PC, PC-loaded chain extender masterbatch, antioxidant, and aromatic acid saturated polyester are added to a high-speed mixer in the following proportions: PC 1–99 wt%, aromatic acid saturated polyester 0.4–70 wt%, PC-loaded chain extender masterbatch 0.4–60 wt%, and antioxidant 0.2–1 wt%. The mixture is then directly melt-extruded to obtain PC composite material.

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