An impact-resistant plastic casing material for electronic products and its preparation method

Abstract

This invention discloses an impact-resistant plastic casing material for electronic products and its preparation method, belonging to the field of polymer materials technology. It mainly addresses the technical problem of how to further improve the strength, impact resistance, and flame retardant properties of plastic casing materials for electronic products. Specifically, it includes the following components by weight: 50-60 parts polycarbonate, 22-28 parts composite polycarbonate, 10-15 parts reinforcing composite, and 2-3 parts auxiliary additives. This invention further improves the strength, impact resistance, and flame retardant properties of plastic casing materials for electronic products through the synergistic effect between the prepared composite polycarbonate, reinforcing composite, and intermediate substances therein.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an impact-resistant plastic casing material for electronic products and its preparation method. Background Technology

[0002] With the rapid development of the consumer electronics industry, the usage scenarios of electronic products are becoming increasingly diverse. The market is placing higher demands on the comprehensive performance of plastic shell materials. They not only need to have good mechanical strength, but also excellent impact resistance, flame retardancy and wear resistance to adapt to complex working conditions such as collisions and friction in daily use, and to ensure product safety and service life.

[0003] Polycarbonate is a common base material for plastic casings of electronic products due to its good rigidity, light transmittance and self-extinguishing properties. However, pure polycarbonate has problems such as insufficient notched impact resistance and poor wear resistance. A single base material is no longer able to meet the performance requirements of high-end electronic devices. Polycarbonate is often modified by copolymerization, blending or adding modifiers, such as introducing flexible segments to improve toughness, adding flame retardants to improve flame retardancy, and adding inorganic fillers to enhance strength. However, various modification schemes often have the problem of poor performance synergy.

[0004] Currently, some modification schemes only focus on improving a single performance. For example, simply adding flame retardants can improve the flame retardancy rating, but it can easily lead to a decline in the mechanical properties of the material. Some blending modifications are difficult to form a stable structural system due to poor compatibility between the components and weak interfacial bonding. This makes it impossible to achieve simultaneous optimization of properties such as impact resistance, high strength, flame retardancy, and wear resistance. At the same time, the composite components used in traditional technical modifications are mostly physically mixed, lacking a stable structure formed by chemical cross-linking. During use, problems such as uneven component dispersion and loss can easily occur, resulting in insufficient material performance stability. In addition, the flame retardant system of electronic casing materials prepared by common polycarbonate modification is mostly single-phase flame retardant, with limited flame retardant effects in the gas phase or condensed phase, making it difficult to construct comprehensive flame retardant protection.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide an impact-resistant plastic casing material for electronic products and its preparation method, mainly addressing the technical problem of how to further improve the strength, impact resistance and flame retardant properties of plastic casing materials for electronic products.

[0007] The objective of this invention can be achieved through the following technical solution: an impact-resistant plastic casing material for electronic products, comprising the following components by weight: 50-60 parts polycarbonate, 22-28 parts composite polycarbonate, 10-15 parts reinforcing composite and 2-3 parts auxiliary additives;

[0008] The preparation method of the enhanced composite is as follows: Under a nitrogen atmosphere, the composite powder and composite silicone oil are added to a reaction vessel containing N,N-dimethylformamide and stirred for 5-10 min. Then, dibutyltin dilaurate is added and the temperature is raised to 140-160℃. The reaction is carried out for 4-6 h. After the reaction is completed, anhydrous ethanol is added and stirred for 1-2 min. After standing for 5-10 min, the lower layer product is collected and washed 3-5 times with anhydrous ethanol. Then, it is placed in a vacuum drying oven and dried at 60℃ to constant weight to obtain the enhanced composite. The composite powder is a maleamide salt modified with DOPO and the composite silicone oil is an amino-terminated polysiloxane.

[0009]

[0010] In the formula:

[0011]

[0012] Furthermore, the ratio of the composite powder, composite silicone oil, N,N-dimethylformamide, and dibutyltin dilaurate is 1g:1.8g:15mL:0.08-0.1g.

[0013] Further, the preparation method of the composite polycarbonate is as follows: under a nitrogen atmosphere, 4,4'-dihydroxydiphenylpropane, 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, diphenyl carbonate and catalyst are added to a reaction vessel. The temperature is raised to 180-200℃ and the materials are completely melted. The mixture is then stirred and reacted for 60-80 min. Next, the temperature is raised to 210-220℃ and a vacuum of 14 kPa is applied. The reaction is carried out for 20-30 min. Then, the temperature is raised to 230-240℃ and a vacuum of 6 kPa is applied. The reaction is carried out for 10-20 min. The temperature is raised again to 250℃ and a vacuum of 4 kPa is applied. The reaction is carried out for 20-30 min. Finally, the temperature is raised to 250℃ and a vacuum of 150-180 Pa is applied. The reaction is carried out for 20-30 min. After the reaction is completed, the composite polycarbonate is obtained through post-processing.

[0014]

[0015] In the formula:

[0016]

[0017] Furthermore, the ratio of 4,4'-dihydroxydiphenylpropane, 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene to the catalyst is 1g:1.1g:0.02g, the amount of diphenyl carbonate added is 1.05 times the total molar amount of hydroxyl groups in 4,4'-dihydroxydiphenylpropane and 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, and the catalyst is sodium hydroxide.

[0018] Furthermore, the composite powder is prepared by the following steps:

[0019] A1. Add maleic anhydride to a reaction vessel containing acetone, stir at 20-25℃ until completely dissolved, then add the mixed solution dropwise at a rate of 5s / drop while stirring. After the addition is complete, react at 30-35℃ for 20-24h. After the reaction is complete, filter, wash the product with acetone 3-4 times, and place it in a vacuum drying oven to dry at 50℃ for 6h to obtain maleamide salt.

[0020]

[0021] A2. Under a nitrogen atmosphere, DOPO is added to the reactor and heated to 110-120℃. After the DOPO is completely melted, maleamide salt is added, and the temperature is further increased to 130-140℃. The mixture is stirred for 3-4 hours. After the reaction is completed, the temperature is lowered to 110-120℃, toluene is added, and the mixture is refluxed for 20-30 minutes. The mixture is then filtered, and the filter cake is washed with toluene 5-6 times. The product is then placed in a drying oven and dried at 120℃ for 8-10 hours to obtain the composite powder.

[0022]

[0023] Further, in step A1, the ratio of maleic anhydride, acetone, and the mixed solution is 4.9g:100-120mL:50mL, and the mixed solution comprises 2.8g potassium hydroxide and 13g 4'-aminoazobenzene-4-sulfonic acid dissolved in 50mL of deionized water; in step A2, the ratio of DOPO, maleamide salt, and toluene is 11g:7.7-8g:150mL.

[0024] Furthermore, the preparation method of the composite silicone oil is as follows: under a nitrogen atmosphere, octamethylcyclotetrasiloxane, 1,3-di(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide are added to a reaction vessel, stirred at 80-90℃ for 10-12h, then heated to 140-150℃ and reacted for another 2-3h. After the reaction is completed, the composite silicone oil is obtained.

[0025] Furthermore, the ratio of the amount of octamethylcyclotetrasiloxane, 1,3-di(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide is 50g:10g:0.1-0.2g.

[0026]

[0027] The present invention also proposes a method for preparing an impact-resistant plastic casing material for electronic products, comprising the following steps: adding polycarbonate, composite polycarbonate, reinforcing composite and auxiliary additives into a high-speed mixer, mixing at 25°C for 10-15 min, adding the mixture into a twin-screw extruder for melt blending and extrusion granulation, and drying the granules under vacuum at 80°C for 2-3 h to obtain the impact-resistant plastic casing material for electronic products.

[0028] Furthermore, the high-speed mixer has a rotation speed of 1200 rpm; the twin-screw extruder has six temperature zones set from the feed end toward the die head, with temperatures of 225°C, 230°C, 235°C, 240°C, 235°C, and 230°C respectively, and the spindle speed of the twin-screw extruder is 80 rpm.

[0029] The present invention has the following beneficial effects:

[0030] 1. The composite polycarbonate of the present invention is formed by copolymerizing 4,4'-dihydroxydiphenylpropane and 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene to form a random copolymer structure. The combination of its aromatic ring and flexible ether bond gives the matrix excellent toughness and crack resistance. The composite powder contains rigid structures such as phosphorus heterophenanthroline ring and amide bond, which can disperse stress when the material is impacted and prevent crack initiation. The flexible polysiloxane segments of the composite silicone oil can effectively absorb impact energy and reduce stress concentration. The reinforcing compound forms a three-dimensional network structure by chemically crosslinking the composite powder and composite silicone oil through amide bonds. This structure can quickly transfer and disperse impact energy to the entire material system. At the same time, the composite polycarbonate and the reinforcing compound form a good interfacial bond. The two are intertwined and synergistically bear the load, which significantly improves the unnotched impact strength and notched impact strength of the simply supported beam of the material. This makes the material less prone to overall fracture when impacted and can also effectively resist crack propagation at the notch.

[0031] 2. The copolymer rigid skeleton of the composite polycarbonate of this invention provides the basic tensile load-bearing capacity of the material. The regularity of its molecular chains and the high-strength aromatic ring structure ensure the tensile stability of the material. The polar and rigid structures such as potassium sulfonate groups and phosphaphenanthrene rings in the composite powder can form physical entanglement with the polycarbonate molecular chains. The three-dimensional cross-linking structure of the reinforcing composite further enhances the overall mechanical strength of the material, enabling the composite polycarbonate and the reinforcing composite to work together under tension, effectively improving the tensile strength of the material. At the same time, the polysiloxane segments of the composite silicone oil have the characteristics of low surface energy. When uniformly dispersed in the material system, they can form a lubricating interface and reduce wear during friction. The cross-linking structure of the reinforcing composite allows the composite silicone oil and composite powder to be stably combined in the material matrix, avoiding the loss of lubricating components. The dense structure of the composite polycarbonate also improves the wear resistance of the material surface. The synergistic effect of each component significantly reduces the mass wear of the material, achieving dual optimization of tensile strength and wear resistance.

[0032] 3. The phosphorus element introduced into the composite powder of this invention exists in the form of a phosphorus-phenanthroline ring structure, which is a highly efficient phosphorus-based flame retardant component. It can exert a flame retardant effect through both gas-phase and condensed-phase flame retardancy. Moreover, after chemical modification, this structure is stably dispersed in the material, greatly improving the flame retardant efficiency. The three-dimensional cross-linked structure of the reinforcing composite can form a dense char layer during the material's combustion, blocking the transfer of oxygen and heat. At the same time, the composite polycarbonate itself is a flame-retardant engineering plastic, and its aromatic ring structure easily forms a char layer during combustion. This char layer is superimposed on the char layer formed by the reinforcing composite, further enhancing the condensed-phase flame retardant effect. The siloxane structure of the composite silicone oil can decompose at high temperatures to form a silica heat insulation layer, which covers the surface of the char layer, improving the structural stability and heat insulation effect of the char layer. The components work synergistically from multiple aspects such as gas-phase flame retardancy, condensed-phase char layer formation, and heat insulation to construct a comprehensive flame retardant system, effectively improving the flame retardant performance of the material and enabling the material to achieve an excellent vertical burning rating. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In this application, the polycarbonate is selected from Shanghai Bangsu New Materials Co., Ltd., with a specification of 25mm, item number HH4260PIEFI7, and grade L-1225Y.

[0035] Example 1

[0036] This embodiment provides a method for preparing an impact-resistant plastic casing material for electronic products, including the following steps:

[0037] S1. Preparation of composite polycarbonate

[0038] Under a nitrogen atmosphere, weigh out: 100g of 4,4'-dihydroxydiphenylpropane and 110g of... 9,9-Di[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, 2g of sodium hydroxide catalyst, and the amount of diphenyl carbonate to be added were calculated as 1.05 times the total molar amount of hydroxyl groups in 4,4'-dihydroxydiphenylpropane and 9,9-di[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene. The mixture was heated to 180°C and stirred for 60 min until the materials were completely melted. Then, the temperature was raised to 210°C and a vacuum of 14 kPa was applied. After reacting for 20 min, the temperature was raised to 230°C and a vacuum of 6 kPa was applied. After reacting for 10 min, the temperature was raised to 250°C and a vacuum of 4 kPa was applied. After reacting for 20 min, the temperature was raised to 250°C and a vacuum of 4 kPa was applied. Finally, the temperature was raised to 250°C and a vacuum of 150 Pa was applied. After reacting for 20 min, the product was dissolved in 1.5 L of dichloromethane and the solution was slowly added dropwise to 8 L of anhydrous ethanol. The precipitate was dried in a drying oven to obtain composite polycarbonate.

[0039] During the reaction, 4,4'-dihydroxydiphenylpropane, 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, and diphenyl carbonate undergo transesterification under gradient heating and stepwise vacuum conditions with an alkaline catalyst. The phenolic hydroxyl groups of 4,4'-dihydroxydiphenylpropane and 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene and diphenyl carbonate undergo transesterification, removing phenolic byproducts and forming oligomers. Subsequently, through pre-condensation and high-vacuum condensation stages, the oligomer segments continue to grow, eventually forming a random copolymer polycarbonate of 4,4'-dihydroxydiphenylpropane-9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene.

[0040] S2, Preparation of maleamide salt

[0041] Weigh out 28g of potassium hydroxide and 130g of 4'-aminoazobenzene-4-sulfonic acid and dissolve them in 500mL of deionized water to obtain a mixed solution;

[0042] Weigh 49g of maleic anhydride and add it to a reaction vessel containing 1000mL of acetone. Stir at 20℃ until completely dissolved, then add 500mL of the mixed solution dropwise at a rate of 5s / drop while stirring. After the addition is complete, react at 30℃ for 20h. After the reaction is complete, filter the solution, wash the product three times with acetone, and then place it in a vacuum drying oven and dry at 50℃ for 6h to obtain maleamide salt.

[0043] During the reaction, in acetone solvent, 4'-aminoazobenzene-4-sulfonic acid is first neutralized with potassium hydroxide to form potassium 4'-aminoazobenzene-4-sulfonate. Its nucleophilic amino group attacks the carbonyl carbon of maleic anhydride, initiating a ring-opening nucleophilic addition reaction of the anhydride ring. Subsequently, through intramolecular proton transfer and dehydration cyclization, a maleamide salt containing a free carboxyl group, an amide bond, and a potassium sulfonate group is formed.

[0044] S3. Preparation of composite powder

[0045] Under a nitrogen atmosphere, 110g of DOPO was weighed and added to a reaction vessel. The temperature was raised to 110℃, and after the DOPO was completely melted, 77g of maleamide salt was added. The temperature was then raised to 130℃, and the mixture was stirred for 3 hours. After the reaction was completed, the temperature was lowered to 110℃, and 1500mL of toluene was added. The mixture was refluxed for 20 minutes, filtered, and the filter cake was washed five times with toluene. The product was then placed in a drying oven and dried at 120℃ for 8 hours to obtain the composite powder.

[0046] During the reaction, under nitrogen protection and heating melting conditions, the active PH bond of DOPO undergoes an addition reaction with the carbon-carbon double bond of maleamide salt to form a new CP bond, introducing the phosphoranone ring structure of DOPO into the maleamide salt molecule, resulting in a composite powder that simultaneously retains the carboxyl group, amide bond, potassium sulfonate group and DOPO flame retardant structure.

[0047] S4. Preparation of composite silicone oil

[0048] Under a nitrogen atmosphere, 500g of octamethylcyclotetrasiloxane, 100g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 1g of tetramethylammonium hydroxide were weighed and added to a reaction vessel. After stirring at 80℃ for 10h, the temperature was raised to 140℃ and the reaction was continued for 2h. After the reaction was completed, composite silicone oil was obtained.

[0049] During the reaction, under nitrogen protection, tetramethylammonium hydroxide acts as an alkaline catalyst, first inducing the ring-opening of octamethylcyclotetrasiloxane to generate an active linear siloxane chain. Subsequently, this active chain undergoes nucleophilic substitution and chain growth reactions with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, causing the aminopropyldimethylsiloxy unit to be attached to both ends of the polysiloxane chain as a capping group, forming a composite silicone oil with amino-terminated ends.

[0050] S5. Preparation of the enhanced complex

[0051] Under a nitrogen atmosphere, 10g of composite powder and 18g of composite silicone oil were weighed and added to a reaction vessel containing 150mL of N,N-dimethylformamide. After stirring for 5 minutes, 0.8g of dibutyltin dilaurate was added, and the temperature was raised to 140℃. The reaction was carried out for 4 hours. After the reaction was completed, anhydrous ethanol was added, and the mixture was stirred for 1 minute. After standing for 5 minutes, the lower layer product was collected, washed three times with anhydrous ethanol, and then placed in a vacuum drying oven and dried at 60℃ to constant weight to obtain the reinforced composite.

[0052] During the reaction, in a nitrogen atmosphere and N,N-dimethylformamide solvent, the free carboxyl groups of the dibutyltin dilaurate catalytic composite powder undergo an amidation reaction with the amino groups at both ends of the composite silicone oil. By forming amide bonds, the composite powder containing the DOPO flame-retardant structure is crosslinked with the amino-terminated polydimethylsiloxane chain to construct a three-dimensional network reinforced composite that combines flame retardancy and flexibility.

[0053] S6. Prepare an impact-resistant plastic casing material for electronic products.

[0054] Weigh out 1 part trioctyl phosphate, 0.6 parts pentaerythritol stearate and 0.1 parts antioxidant 1010 by weight, mix them evenly to obtain the auxiliary additive;

[0055] Weigh out the following by weight: 50 parts polycarbonate, 22 parts composite polycarbonate, 10 parts reinforcing composite and 2 parts auxiliary additives into a high-speed mixer and mix for 10 minutes at 1200 rpm at 25°C. Add the mixture into a twin-screw extruder. Set the temperatures of the six temperature zones of the twin-screw extruder from the feed end toward the die head to 225°C, 230°C, 235°C, 240°C, 235°C and 230°C respectively. Set the spindle speed to 80 rpm. Perform melt blending, extrusion and granulation. Dry the granules under vacuum at 80°C for 2 hours to obtain impact-resistant plastic casing material for electronic products.

[0056] Example 2

[0057] This embodiment provides an impact-resistant plastic casing material for electronic products and its preparation method, including the following steps:

[0058] S1. Preparation of composite polycarbonate

[0059] Under a nitrogen atmosphere, weigh out: 100g of 4,4'-dihydroxydiphenylpropane and 110g of... 9,9-Di[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, 2g of sodium hydroxide catalyst, and the amount of diphenyl carbonate to be added were calculated as 1.05 times the total molar amount of hydroxyl groups in 4,4'-dihydroxydiphenylpropane and 9,9-di[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene. The mixture was heated to 190℃ and stirred for 70 min until the materials were completely melted. Then, the temperature was raised to 215℃ and a vacuum of 14 kPa was applied. After reacting for 25 min, the temperature was raised to 235℃ and a vacuum of 6 kPa was applied. After reacting for 15 min, the temperature was raised to 250℃ and a vacuum of 4 kPa was applied. After reacting for 25 min, the temperature was raised to 250℃ and a vacuum of 4 kPa was applied. Finally, the temperature was raised to 250℃ and a vacuum of 165 Pa was applied. After reacting for 25 min, the product was dissolved in 1.75 L of dichloromethane and the solution was slowly added dropwise to 9 L of anhydrous ethanol. The precipitate was dried in a drying oven to obtain composite polycarbonate.

[0060] S2, Preparation of maleamide salt

[0061] Weigh out 28g of potassium hydroxide and 130g of 4'-aminoazobenzene-4-sulfonic acid and dissolve them in 500mL of deionized water to obtain a mixed solution;

[0062] Weigh 49g of maleic anhydride and add it to a reaction vessel containing 1100mL of acetone. Stir at 20℃ until completely dissolved, then add 500mL of the mixed solution dropwise at a rate of 5s / drop while stirring. After the addition is complete, react at 30℃ for 22h. After the reaction is complete, filter the solution, wash the product three times with acetone, and then place it in a vacuum drying oven and dry at 50℃ for 6h to obtain maleamide salt.

[0063] S3. Preparation of composite powder

[0064] Under a nitrogen atmosphere, 110g of DOPO was weighed and added to a reaction vessel. The temperature was raised to 115℃, and after the DOPO was completely melted, 78g of maleamide salt was added. The temperature was then raised to 134℃, and the mixture was stirred for 3.5h. After the reaction was completed, the temperature was lowered to 115℃, and 1500mL of toluene was added. The mixture was refluxed for 25min, filtered, and the filter cake was washed 5 times with toluene. The product was then placed in a drying oven and dried at 120℃ for 9h to obtain the composite powder.

[0065] S4. Preparation of composite silicone oil

[0066] Under a nitrogen atmosphere, 500g of octamethylcyclotetrasiloxane, 100g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 1.5g of tetramethylammonium hydroxide were weighed and added to a reaction vessel. After stirring at 85°C for 11 hours, the temperature was raised to 145°C and the reaction was continued for 2.5 hours. After the reaction was completed, composite silicone oil was obtained.

[0067] S5. Preparation of the enhanced complex

[0068] Under a nitrogen atmosphere, 10g of composite powder and 18g of composite silicone oil were weighed and added to a reaction vessel containing 150mL of N,N-dimethylformamide. After stirring for 8 minutes, 0.9g of dibutyltin dilaurate was added, and the temperature was raised to 150℃. The reaction was carried out for 5 hours. After the reaction was completed, anhydrous ethanol was added, and the mixture was stirred for 1 minute. After standing for 8 minutes, the lower layer product was collected, washed 4 times with anhydrous ethanol, and then placed in a vacuum drying oven and dried at 60℃ to constant weight to obtain the reinforced composite.

[0069] S6. Prepare an impact-resistant plastic casing material for electronic products.

[0070] Weigh out 1.5 parts by weight of trioctyl phosphate, 0.7 parts by weight of pentaerythritol stearate and 0.15 parts by weight of antioxidant 1010, mix them evenly to obtain the auxiliary additive;

[0071] Weigh out the following by weight: 55 parts polycarbonate, 25 parts composite polycarbonate, 12 parts reinforcing composite and 2.5 parts auxiliary additives and add them to a high-speed mixer. Mix at 1200 rpm for 12 minutes at 25°C. Add the mixture to a twin-screw extruder. Set the temperatures of the six temperature zones of the twin-screw extruder from the feed end toward the die head to 225°C, 230°C, 235°C, 240°C, 235°C and 230°C respectively. Set the spindle speed to 80 rpm. Perform melt blending, extrusion and granulation. Dry the granules under vacuum at 80°C for 2.5 hours to obtain impact-resistant plastic casing material for electronic products.

[0072] Example 3

[0073] This embodiment provides an impact-resistant plastic casing material for electronic products and its preparation method, including the following steps:

[0074] S1. Preparation of composite polycarbonate

[0075] Under a nitrogen atmosphere, weigh out: 100g of 4,4'-dihydroxydiphenylpropane and 110g of... 9,9-Di[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, 2g of sodium hydroxide catalyst, and the amount of diphenyl carbonate to be added were calculated as 1.05 times the total molar amount of hydroxyl groups in 4,4'-dihydroxydiphenylpropane and 9,9-di[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene. The mixture was heated to 200℃ and stirred for 80 min until the materials were completely melted. Then, the temperature was raised to 220℃ and the vacuum was reduced to 14 kPa. After reacting for 30 min, the temperature was raised to 240℃ and the vacuum was reduced to 6 kPa. After reacting for 20 min, the temperature was raised to 250℃ and the vacuum was reduced to 4 kPa. After reacting for 30 min, the temperature was raised to 250℃ and the vacuum was reduced to 4 kPa. Finally, the vacuum was reduced to 180 Pa at 250℃ and the reaction was carried out for 30 min. After the reaction was completed, the product was dissolved in 2 L of dichloromethane and the solution was slowly added dropwise to 10 L of anhydrous ethanol. The precipitate was dried in a drying oven to obtain composite polycarbonate.

[0076] S2, Preparation of maleamide salt

[0077] Weigh out 28g of potassium hydroxide and 130g of 4'-aminoazobenzene-4-sulfonic acid and dissolve them in 500mL of deionized water to obtain a mixed solution;

[0078] Weigh 49g of maleic anhydride and add it to a reaction vessel containing 1200mL of acetone. Stir at 25℃ until completely dissolved, then add 500mL of the mixed solution dropwise at a rate of 5s / drop while stirring. After the addition is complete, react at 35℃ for 24h. After the reaction is complete, filter the solution, wash the product four times with acetone, and then place it in a vacuum drying oven and dry at 50℃ for 6h to obtain maleamide salt.

[0079] S3. Preparation of composite powder

[0080] Under a nitrogen atmosphere, 110g of DOPO was weighed and added to a reaction vessel. The temperature was raised to 120℃, and after the DOPO was completely melted, 80g of maleamide salt was added. The temperature was then raised to 140℃ and stirred for 4 hours. After the reaction was completed, the temperature was lowered to 120℃, and 1500mL of toluene was added. The mixture was refluxed for 30 minutes and then filtered. The filter cake was washed 6 times with toluene, and the product was placed in a drying oven and dried at 120℃ for 10 hours to obtain the composite powder.

[0081] S4. Preparation of composite silicone oil

[0082] Under a nitrogen atmosphere, 500g of octamethylcyclotetrasiloxane, 100g of 1,3-di(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 2g of tetramethylammonium hydroxide were weighed and added to a reaction vessel. After stirring at 90℃ for 12h, the temperature was raised to 150℃ and the reaction was continued for 3h. After the reaction was completed, composite silicone oil was obtained.

[0083] S5. Preparation of the enhanced complex

[0084] Under a nitrogen atmosphere, 10g of composite powder and 18g of composite silicone oil were weighed and added to a reaction vessel containing 150mL of N,N-dimethylformamide. After stirring for 10min, 1g of dibutyltin dilaurate was added and the temperature was raised to 160℃. The reaction was carried out for 6h. After the reaction was completed, anhydrous ethanol was added and stirred for 2min. After standing for 10min, the lower layer product was collected, washed 5 times with anhydrous ethanol, and then placed in a vacuum drying oven and dried at 60℃ to constant weight to obtain the reinforced composite.

[0085] S6. Prepare an impact-resistant plastic casing material for electronic products.

[0086] Weigh out 2 parts by weight of trioctyl phosphate, 0.8 parts by weight of pentaerythritol stearate and 0.2 parts by weight of antioxidant 1010, mix them evenly to obtain the auxiliary additive;

[0087] Weigh out the following by weight: 60 parts polycarbonate, 28 parts composite polycarbonate, 15 parts reinforcing composite and 3 parts auxiliary additives into a high-speed mixer and mix for 15 minutes at 1200 rpm at 25°C. Add the mixture into a twin-screw extruder. Set the temperatures of the six temperature zones of the twin-screw extruder from the feed end toward the die head to 225°C, 230°C, 235°C, 240°C, 235°C and 230°C respectively. Set the spindle speed to 80 rpm. Perform melt blending, extrusion and granulation. Dry the granules under vacuum at 80°C for 3 hours to obtain impact-resistant plastic casing material for electronic products.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 3 is that step S1 is omitted, and no composite polycarbonate is added in step S6; only a single polycarbonate is used.

[0090] Comparative Example 2

[0091] The difference between this comparative example and Example 3 is that steps S3 and S5 are omitted, and the composite powder prepared in step S3 is used to replace the reinforcing composite in step S6.

[0092] Comparative Example 3

[0093] The difference between this comparative example and Example 3 is that steps S4 and S5 are omitted, and the composite silicone oil prepared in step S4 is used to replace the reinforcing composite in step S6.

[0094] Comparative Example 4

[0095] The difference between this comparative example and Example 3 is that steps S3, S4 and S5 are omitted, and the reinforcing complex in step S6 is replaced by a mixture of DOPO in step S3 and octamethylcyclotetrasiloxane in step S4.

[0096] Performance testing:

[0097] The unnotched and notched impact strengths of the simply supported beams of the impact-resistant electronic product plastic casing materials prepared in Examples 1-3 and Comparative Examples 1-4 were determined in accordance with the standard GB / T 1043.1-2008 "Determination of impact properties of simply supported beams of plastics - Part 1: Non-instrumental impact test".

[0098] The tensile strength of the impact-resistant plastic casing materials for electronic products prepared in Examples 1-3 and Comparative Examples 1-4 was determined in accordance with the standard GB / T 1040.1-2025 "Determination of tensile properties of plastics - Part 1: General".

[0099] The mass wear of the impact-resistant plastic casing materials for electronic products prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to the standard GB / T 3960-2016 "Plastics - Test Method for Sliding Friction and Wear".

[0100] The vertical flammability ratings of the impact-resistant electronic product plastic casing materials prepared in Examples 1-3 and Comparative Examples 1-4 were determined according to standard GB / T 2408-2021 "Determination of Burning Performance of Plastics - Horizontal and Vertical Methods". Specific test results are shown in Table 1 below:

[0101] Table 1 - Performance Test Data of Samples

[0102]

[0103] Data Analysis:

[0104] Comparative analysis of the data in Table 1 above shows that the impact-resistant plastic casing material for electronic products prepared by this invention has a notched impact strength of 102.6 kJ / m². 2 The notched impact strength of the simply supported beam is 31.1 kJ / m. 2 The tensile strength is 74.2 MPa, the mass wear is 0.0087 g, and the vertical burning rating is V-0.

[0105] Comparative Example 1, by eliminating the composite polycarbonate and using only single polycarbonate, lost the synergistic effect of the aromatic rings and flexible ether bonds in the copolymer structure, resulting in a significant decrease in matrix toughness. Simultaneously, the interfacial bonding with the reinforcing composite deteriorated, preventing effective dispersion of impact energy, leading to a drop in its unnotched impact strength to 49.9 kJ / m. 2 The notched impact strength is only 11.4 kJ / m. 2 In terms of tensile strength, due to the lack of load-bearing support from the copolymer rigid skeleton, the tensile strength drops to 52.6 MPa. The wear resistance and flame retardant properties are also affected by the matrix structure, with the mass wear amount rising to 0.0154 g and the vertical burning rating only reaching V-1.

[0106] Comparative Example 2, due to the elimination of the reinforcing compound and the use of composite powder instead, lacks the three-dimensional network structure formed by the cross-linking of flexible segments without composite silicone oil. Impact energy cannot be rapidly transferred and dispersed; stress is dispersed solely by the composite powder, resulting in a notched impact strength of 60.3 kJ / m for the simply supported beam. 2 Notched impact strength: 17.9 kJ / m 2 At the same time, without the lubricating effect of silicone oil and lacking the stable bonding of cross-linked structure, the wear resistance of the material surface drops sharply, and the mass wear amount increases significantly to 0.0275g. Only because the complete composite powder is retained, the flame retardancy still reaches V-0, and the tensile strength of 61.4MPa is also retained to a certain level.

[0107] Comparative Example 3, by eliminating the reinforcing compound and replacing it with composite silicone oil, completely removed the composite powder containing phosphorus and phenanthrene rings. Without a rigid structure to disperse stress and provide flame retardancy, the vertical flammability rating was only V-2. In terms of tensile strength, due to the lack of a rigid structure and physical entanglement, the tensile strength decreased to 48.7 MPa. Although the flexible segments of the silicone oil allowed the impact strength to remain at 67.4 kJ / m... 2 and 20.5 kJ / m 2 Furthermore, the low surface energy resulted in a mass wear amount of 0.0121g, which was superior to that of Comparative Examples 1 and 2. However, without the synergy of composite powder, the material lost its rigidity and flame retardancy, and could not achieve comprehensive performance.

[0108] Comparative Example 4, due to the omission of the complete preparation of composite powder, composite silicone oil, and reinforcing compound, only physically mixed DOPO and octamethylcyclotetrasiloxane, lacked the three-dimensional structure formed by chemical cross-linking and the synergistic effect of the modified components, resulting in a significant drop in impact performance, with a notched impact strength of only 44.7 kJ / m for a simply supported beam. 2 Notched impact strength 8.7 kJ / m 2 Its tensile strength of 45.4 MPa is also at the bottom. The components of the physical mixture are easily lost, which increases the mass wear amount to 0.0334 g. DOPO is also unevenly dispersed due to lack of chemical modification, and its flame retardancy is only V-2.

[0109] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An impact-resistant plastic casing material for electronic products, characterized in that, Includes the following components by weight: 50-60 parts polycarbonate, 22-28 parts composite polycarbonate, 10-15 parts reinforcing composite and 2-3 parts auxiliary additives; The preparation method of the enhanced composite is as follows: Under a nitrogen atmosphere, the composite powder and composite silicone oil are added to a reaction vessel containing N,N-dimethylformamide and stirred for 5-10 min. Then, dibutyltin dilaurate is added and the temperature is raised to 140-160℃. The reaction is carried out for 4-6 h. After the reaction is completed, anhydrous ethanol is added and stirred for 1-2 min. After standing for 5-10 min, the lower layer product is collected and washed 3-5 times with anhydrous ethanol. Then, it is placed in a vacuum drying oven and dried at 60℃ to constant weight to obtain the enhanced composite. The composite powder is a maleamide salt modified with DOPO and the composite silicone oil is an amino-terminated polysiloxane.

2. The impact-resistant plastic casing material for electronic products according to claim 1, characterized in that, The ratio of the composite powder, composite silicone oil, N,N-dimethylformamide and dibutyltin dilaurate is 1g:1.8g:15mL:0.08-0.1g.

3. The impact-resistant plastic casing material for electronic products according to claim 2, characterized in that, The preparation method of the composite polycarbonate is as follows: Under a nitrogen atmosphere, 4,4'-dihydroxydiphenylpropane, 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene, diphenyl carbonate and catalyst are added to a reaction vessel. The temperature is raised to 180-200℃ and the materials are completely melted. The mixture is then stirred and reacted for 60-80 min. The temperature is then raised to 210-220℃ and a vacuum of 14 kPa is applied. The reaction is carried out for 20-30 min. The temperature is then raised to 230-240℃ and a vacuum of 6 kPa is applied. The reaction is carried out for 10-20 min. The temperature is then raised to 250℃ and a vacuum of 4 kPa is applied. The reaction is carried out for 20-30 min. Finally, the temperature is raised to 250℃ and a vacuum of 150-180 Pa is applied. The reaction is carried out for 20-30 min. After the reaction is completed, the composite polycarbonate is obtained through post-processing.

4. The impact-resistant plastic casing material for electronic products according to claim 3, characterized in that, The ratio of 4,4'-dihydroxydiphenylpropane, 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene to the catalyst is 1 g:1.1 g:0.02 g. The amount of diphenyl carbonate added is 1.05 times the total molar amount of hydroxyl groups in 4,4'-dihydroxydiphenylpropane and 9,9-bis[3-phenyl-4-(2-hydroxyethoxy)phenyl]fluorene. The catalyst is sodium hydroxide.

5. The impact-resistant plastic casing material for electronic products according to claim 4, characterized in that, The composite powder is prepared by the following steps: A1. Add maleic anhydride to a reaction vessel containing acetone, stir at 20-25℃ until completely dissolved, then add the mixed solution dropwise at a rate of 5s / drop while stirring. After the addition is complete, react at 30-35℃ for 20-24h. After the reaction is complete, filter, wash the product with acetone 3-4 times, and place it in a vacuum drying oven to dry at 50℃ for 6h to obtain maleamide salt. A2. Under a nitrogen atmosphere, DOPO is added to the reactor and heated to 110-120℃. After the DOPO is completely melted, maleamide salt is added, and the temperature is further increased to 130-140℃. The mixture is stirred for 3-4 hours. After the reaction is completed, the temperature is lowered to 110-120℃, toluene is added, and the mixture is refluxed for 20-30 minutes. The mixture is then filtered, and the filter cake is washed with toluene 5-6 times. The product is then placed in a drying oven and dried at 120℃ for 8-10 hours to obtain the composite powder.

6. The impact-resistant plastic casing material for electronic products according to claim 5, characterized in that, In step A1, the ratio of maleic anhydride, acetone, and the mixed solution is 4.9g:100-120mL:50mL, and the mixed solution is obtained by dissolving 2.8g of potassium hydroxide and 13g of 4'-aminoazobenzene-4-sulfonic acid in 50mL of deionized water; in step A2, the ratio of DOPO, maleamide salt, and toluene is 11g:7.7-8g:150mL.

7. The impact-resistant plastic casing material for electronic products according to claim 6, characterized in that, The method for preparing the composite silicone oil is as follows: Under a nitrogen atmosphere, octamethylcyclotetrasiloxane, 1,3-di(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide are added to a reaction vessel, stirred at 80-90℃ for 10-12 hours, then heated to 140-150℃ and reacted for another 2-3 hours. After the reaction is completed, the composite silicone oil is obtained.

8. The impact-resistant plastic casing material for electronic products according to claim 7, characterized in that, The ratio of octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide is 50g:10g:0.1-0.2g.

9. A method for preparing an impact-resistant plastic casing material for electronic products, applied to the impact-resistant plastic casing material for electronic products as described in claim 8, characterized in that, The process includes the following steps: adding polycarbonate, composite polycarbonate, reinforcing composite and auxiliary additives into a high-speed mixer and mixing at 25°C for 10-15 minutes; adding the mixture into a twin-screw extruder for melt blending and granulation; and drying the granules under vacuum at 80°C for 2-3 hours to obtain an impact-resistant plastic casing material for electronic products.

10. The method for preparing an impact-resistant plastic casing material for electronic products according to claim 9, characterized in that, The high-speed mixer rotates at 1200 rpm; the twin-screw extruder has six temperature zones set from the feed end toward the die head, with temperatures of 225°C, 230°C, 235°C, 240°C, 235°C, and 230°C respectively; and the spindle speed of the twin-screw extruder is 80 rpm.

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