ABS (Acrylonitrile Butadiene Styrene) material for camera shell and preparation method of ABS material

Abstract

The invention provides an ABS (Acrylonitrile Butadiene Styrene) material for a camera shell and a preparation method of the ABS material, and belongs to the field of ABS materials. The ABS material is prepared from the following raw materials in parts by weight: 75 to 85 parts of ABS resin, 8 to 12 parts of a reactive core-shell assembly agent, 2 to 4 parts of polymethyl methacrylate, 1 to 3 parts of ammonia-terminated polydimethylsiloxane, 2 to 4 parts of organic montmorillonite, 1 to 3 parts of porous silicon dioxide nanospheres loaded with a hindered amine light stabilizer, 0.5 to 2 parts of carbon nanotubes, 1.0 to 2.5 parts of an amphiphilic nanoscale polymer grafting agent, 0.3 to 0.5 part of lanthanum benzoate and 0.3 to 0.5 part of a composite antioxidant. And 0.1 to 0.5 part of a hexamethylene diisocyanate tripolymer. The rigidity, toughness, dimensional stability and long-term weather resistance of the ABS material are synchronously improved essentially through specific molecular structure design of the components and a synergistic effect network formed in the processing process.

Description

Technical Field

[0001] This application relates to the field of ABS material technology, and in particular to an ABS material for camera housings and a method for preparing the same. Background Technology

[0002] ABS resin, as a thermoplastic engineering plastic with excellent comprehensive performance, is widely used in consumer electronics housings and other fields due to its good rigidity, toughness, processing flowability, and surface gloss. However, as high-end camera modules develop towards higher pixels, miniaturization, and precision, their housing materials face unprecedentedly stringent performance requirements: extremely high rigidity to ensure structural stability and protect internal precision optical components; excellent toughness to resist drops and impacts; outstanding dimensional stability, i.e., an extremely low linear coefficient of thermal expansion and low water absorption rate, to ensure minimal dimensional changes under different temperature and humidity environments, preventing lens focusing misalignment or changes in assembly gaps; and excellent long-term weather resistance to resist yellowing, surface chalking, and mechanical property degradation caused by ultraviolet light and thermo-oxidative aging. Traditional general-purpose ABS resin or conventional modified ABS materials struggle to simultaneously meet these conflicting performance requirements.

[0003] Currently, research on ABS modification often focuses on improving single or a few properties. For example, adding glass fibers, mineral fillers, or blends with high-rigidity polymers (such as polycarbonate) can improve rigidity and heat resistance, but this method usually leads to a significant decrease in toughness and processing fluidity, and has limited improvement on dimensional stability. Toughening with elastomers (such as nitrile rubber and acrylate rubber) or core-shell impact modifiers is a common approach, but this often sacrifices the material's rigidity, strength, and heat resistance. Adding layered silicates (such as montmorillonite) and other nanofillers is an effective way to improve dimensional stability, but their dispersibility in the matrix and interfacial adhesion are technical challenges. Improper treatment can easily lead to agglomeration, becoming stress concentration points, impairing toughness, and offering no direct contribution to weather resistance. Regarding weather resistance, external UV absorbers and antioxidants are usually added, but small-molecule additives have problems such as easy migration, volatility, and insufficient durability, resulting in limited long-term protective effects, and their compatibility with the matrix may affect the material's transparency or surface properties. Therefore, developing a new type of ABS material that can build an integrated, reinforced, and stable network through chemical reactions and physical interactions between its components, starting from molecular design, has become an inevitable technological direction to meet the demanding application requirements of high-end camera housings. Summary of the Invention

[0004] This application provides an ABS material for camera housings and a method for preparing the same, in order to solve the following technical problem: how to simultaneously improve the rigidity, toughness, dimensional stability and long-term weather resistance of ABS materials used for camera housings.

[0005] In a first aspect, this application provides an ABS material for a camera housing, wherein, by weight, the ABS material is composed of the following raw materials: ABS resin: 75-85 parts, reactive core-shell assembly agent: 8-12 parts, polymethyl methacrylate: 2-4 parts, amino-terminated polydimethylsiloxane: 1-3 parts, organomodified montmorillonite: 2-4 parts, porous silica nanospheres loaded with hindered amine light stabilizer: 1-3 parts, carbon nanotubes: 0.5-2 parts, amphiphilic nanoscale polymer grafting agent: 1.0-2.5 parts, lanthanum benzoate: 0.3-0.5 parts, composite antioxidant: 0.3-0.5 parts, and hexamethylene diisocyanate trimer: 0.1-0.5 parts; The reactive core-shell assembling agent is a particle with a core-shell structure, wherein the core is cross-linked polystyrene and the shell is a poly(hydroxyethyl methacrylate-co-styrene) copolymer; The amphiphilic nanoscale polymer grafting agent is a linear diblock copolymer containing hydrophobic polystyrene blocks and hydrophilic reactive polymethyl methacrylate blocks.

[0006] Optionally, the preparation method of the reactive core-shell assembling agent includes the following steps: S101. Under inert gas protection, styrene monomer, crosslinking agent divinylbenzene and initiator azobisisobutyronitrile are dissolved in an organic solvent and dispersed polymerized at 70-85°C for 4-8 hours. After centrifugation, washing and drying, crosslinked polystyrene nanospheres with a particle size of 80-120 nm are obtained. S102. The cross-linked polystyrene nanospheres are dispersed in an alcohol-water mixed solvent containing polyvinylpyrrolidone dispersant, and a uniform dispersion is formed under the combined action of stirring and ultrasound. S103. Hydroxyethyl methacrylate monomer, styrene monomer and initiator azobisisobutyronitrile are added sequentially to the dispersion, and the mixture is reacted at 75-80°C for 5-10 hours to form a poly(hydroxyethyl methacrylate-co-styrene) copolymer shell on the hard core surface through graft copolymerization. After the reaction is completed, the mixture is centrifuged, washed and vacuum dried to obtain the reactive core-shell assembly agent.

[0007] Optionally, in step S101, the mass ratio of the styrene monomer, the crosslinking agent divinylbenzene, and the initiator azobisisobutyronitrile is 100:(2-10):(0.5-2.0); In step S102, the mass of the polyvinylpyrrolidone dispersant is 5% to 15% of the mass of the cross-linked polystyrene nanospheres; In step S103, the mass ratio of the hydroxyethyl methacrylate monomer to the styrene monomer is (6-9):(1-4); the ratio of the total mass of the hydroxyethyl methacrylate monomer and the styrene monomer to the mass of the cross-linked polystyrene nanospheres is 0.5:1-2:1; and the mass of the initiator azobisisobutyronitrile is 0.5-2.0% of the total mass of the hydroxyethyl methacrylate monomer and the styrene monomer.

[0008] Optionally, the method for preparing the porous silica nanospheres loaded with hindered amine light stabilizers includes the following steps: S201. Porous silica nanospheres are immersed in an organic solvent solution containing hindered amine light stabilizer and ultrasonically treated at 40-60℃ for 1-3 hours. After solid-liquid separation, a primary powder loaded with hindered amine light stabilizer is obtained. S202 Under vacuum conditions, the primary powder is heat-treated at 80-100°C for 2-4 hours, then a silane coupling agent is added, and the mixture is reacted at 100-120°C for 1-2 hours to obtain the porous silica nanospheres loaded with hindered amine light stabilizers.

[0009] Optionally, in step S201, the mass ratio of the porous silica nanospheres to the hindered amine light stabilizer is 10:(2-5), and the hindered amine light stabilizer is light stabilizer UV-944; In step S202, the mass of the silane coupling agent is 1 to 5% of the initial mass of the porous silica nanospheres, and the silane coupling agent is γ-aminopropyltriethoxysilane.

[0010] Optionally, the preparation method of the amphiphilic nanoscale polymer grafting agent includes the following steps: S301. Under inert gas protection, styrene monomer, ethyl α-bromoisobutyrate initiator, and a catalytic system composed of cuprous chloride and N,N,N',N'',N''-pentamethyldiethylenetriamine are dissolved in an organic solvent and subjected to atom transfer radical polymerization at 100-120°C for 4-8 hours. After the reaction, the mixture is precipitated, washed, and vacuum dried to obtain a polystyrene macromolecular initiator with bromine atoms at the end. S302. The polystyrene macromolecular initiator is redissolved in an organic solvent, and glycidyl methacrylate monomer is added. Under the action of the catalytic system, the atom transfer radical polymerization reaction is continued at 80-100°C for 6-12 hours. After the reaction is completed, the mixture is precipitated, washed and vacuum dried to obtain the amphiphilic nanoscale polymer grafting agent.

[0011] Optionally, in step S301, the molar ratio of the styrene monomer to the initiator ethyl α-bromoisobutyrate is (80-200):1; the molar ratio of the cuprous chloride to the N,N,N',N'',N''-pentamethyldiethylenetriamine is 1:(1-1.5).

[0012] In step S302, the molar ratio of the glycidyl methacrylate monomer to the polystyrene macromolecular initiator is (30-100):1.

[0013] Optionally, the composite antioxidant is composed of a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the secondary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The mass ratio of the primary antioxidant to the secondary antioxidant is 1:(1-2).

[0014] Secondly, this application provides a method for preparing ABS material for camera housing as described in any one of the first aspects, the method comprising the following steps: S1. Organic montmorillonite, porous silica nanospheres loaded with hindered amine light stabilizer, carbon nanotubes and some ABS resin powder are dry mixed in a high-speed mixer to obtain nanofiller premix. S2. Polymethyl methacrylate, amino-terminated polydimethylsiloxane, lanthanum benzoate, composite antioxidant and the remaining ABS resin powder are mixed in a high-speed mixer to obtain a matrix functional premix. S3. The matrix functional premix, the nanofiller premix, the reactive core-shell assembly agent, and the amphiphilic nanoscale polymer grafting agent are fed into the main feed hopper of a twin-screw extruder. The hexamethylene diisocyanate trimer is injected into the rear part of the melting section through a side-line liquid injection pump. Under the action of screw shearing and vacuum degassing, the mixture is melt-blended and reacted. After extrusion, water cooling, and pelletizing, modified ABS granules are obtained. S4. The modified ABS particles are dried in a forced-air dryer at 75-85°C for 3-5 hours to obtain the ABS material for camera housing that can be used for injection molding.

[0015] Optionally, in step S1, the mass of a portion of the ABS resin powder is 20-30% of the total mass of the ABS resin powder; In step S2, the temperature of each section of the twin-screw extruder is 175-200℃, the screw length-to-diameter ratio is 40:1-48:1, and the screw speed is 200-350 rpm. The vacuum level of the vacuum exhaust is not lower than -0.08 MPa.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art: This application discloses an ABS material for camera housings, which, through the specific molecular structure design of each component and the synergistic network formed during processing, fundamentally and simultaneously improves the rigidity, toughness, dimensional stability, and long-term weather resistance of the ABS material.

[0017] The increased rigidity stems from the synergistic effect of a triple reinforcement mechanism: First, the rigid cross-linked polystyrene core, which reacts with the core-shell assemblies, acts as dispersed nano-reinforcing points, directly bearing stress. Second, organo-modified montmorillonite, carbon nanotubes, and supported porous silica nanospheres form an interlocking nano-reinforcing framework within the matrix, physically restricting molecular chain movement. Most importantly, hexamethylene diisocyanate trimer acts as a cross-linking agent, chemically reacting with the hydroxyl groups of the core-shell assemblies' shell, the amino groups of the amino-terminated polydimethylsiloxane, and the active groups of the amphiphilic nanoscale polymer grafting agent to generate a three-dimensional covalently cross-linked network in situ. This network chemically bonds all the aforementioned rigid units into a unified whole, significantly enhancing the overall modulus and resistance to deformation of the material.

[0018] The improved toughness is achieved through a multi-scale energy dissipation mechanism, avoiding the embrittlement that might result from increased rigidity. The flexible copolymer shell of the reactive core-shell assembler ensures strong interfacial adhesion between the rigid core and the ABS matrix, making the particles energy dissipation points that initiate and terminate crazes. The amphiphilic nanoscale polymer grafting agent acts as a "molecular bridge," with its polystyrene blocks anchored to the matrix and its polyglycidyl methacrylate blocks interacting with the cross-linked network and fillers, uniformly transferring and dissipating impact energy. Simultaneously, well-dispersed carbon nanotubes absorb a large amount of energy through bridging and pull-out processes. These mechanisms effectively hinder crack propagation when the material is subjected to impact.

[0019] The significant improvement in dimensional stability is directly attributable to the physical barrier effect of the chemical cross-linking network and the nanofiller. The three-dimensional covalent network facilitated by hexamethylene diisocyanate trimer fundamentally and significantly restricts the thermal freedom of polymer molecular chains and the swelling space, which is the molecular basis for obtaining an extremely low linear coefficient of thermal expansion. At the same time, the layered organic montmorillonite and the spherical porous silica nanospheres form tortuous barrier pathways in the matrix, which not only inhibit the thermal movement of molecular chains but also effectively hinder the penetration and diffusion of water molecules, thereby synergistically reducing the thermal expansion and hygroscopicity of the material and ensuring the long-term stability of the precision shell dimensions.

[0020] Long-term weather resistance is ensured through a multi-layered, synergistic stabilization system. Lanthanum benzoate, as a UV absorber, is the first to convert incident UV light energy into harmless heat energy. Porous silica nanospheres loaded with hindered amine light stabilizers are the core of this design. Their porous structure acts as a "nano-reservoir," achieving physical loading and controlled slow release of the light stabilizer, ensuring continuous and efficient capture of free radicals throughout the material's entire lifespan, overcoming the migration and early consumption problems caused by direct addition. The composite antioxidant, through the synergy of primary and secondary antioxidants, inhibits thermo-oxidative aging during processing and long-term use, respectively. In addition, amino-terminated polydimethylsiloxane participates in crosslinking and surface migration to form a chemically anchored surface lubricating layer, which can reduce surface friction and degradation caused by photoaging.

[0021] In summary, this application is not a simple blend, but rather establishes a rigidity and dimensional stability foundation through a chemical cross-linking network constructed from hexamethylene diisocyanate trimer and active components. Interfacial toughening and stress transfer are achieved through reactive core-shell assembly agents and amphiphilic nanoscale polymer grafting agents, and a multi-layered protective system is formed through lanthanum benzoate, supported light stabilizers, and composite antioxidants. Based on their precise molecular structures, each component forms a multi-level synergy within the material, ranging from covalent bonds and hydrogen bonds to physical entanglements, thus comprehensively resolving the technical contradiction of simultaneously achieving high rigidity, high toughness, high dimensional stability, and high weather resistance. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic flowchart illustrating a method for preparing ABS material for a camera housing, provided in an embodiment of this application; Figure 2 A physical image of the camera housing made of the ABS material of Example 1 provided for this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0027] This application provides an ABS material for camera housing, which, by weight, is composed of the following raw materials: ABS resin: 75-85 parts, reactive core-shell assembly agent: 8-12 parts, polymethyl methacrylate: 2-4 parts, amino-terminated polydimethylsiloxane: 1-3 parts, organomodified montmorillonite: 2-4 parts, porous silica nanospheres loaded with hindered amine light stabilizer: 1-3 parts, carbon nanotubes: 0.5-2 parts, amphiphilic nanoscale polymer grafting agent: 1.0-2.5 parts, lanthanum benzoate: 0.3-0.5 parts, composite antioxidant: 0.3-0.5 parts, and hexamethylene diisocyanate trimer: 0.1-0.5 parts; Among them, the reactive core-shell assembling agent is a particle with a core-shell structure, the core being cross-linked polystyrene and the shell being a poly(hydroxyethyl methacrylate-co-styrene) copolymer; The amphiphilic nanoscale polymer grafting agent is a linear diblock copolymer containing hydrophobic polystyrene blocks and hydrophilic reactive polymethyl methacrylate blocks.

[0028] This material system uses ABS resin as the continuous phase matrix. ABS resin itself is a multiphase structure formed by graft copolymerization of acrylonitrile (A), butadiene (B), and styrene (S): the styrene-acrylonitrile copolymer (SAN) constitutes the continuous phase, providing rigidity, strength, and processing fluidity; the polybutadiene rubber phase dispersed within it absorbs impact energy by inducing crazes and shear bands, providing basic toughness. All functional components in this scheme are designed to strengthen this multiphase structure and build a more advanced synergistic network.

[0029] (1) Reactive core-shell assembly agent: Its molecular structure is precisely designed as a "rigid core-reactive shell" core-shell structure. The core is a highly cross-linked polystyrene three-dimensional network. This cross-linked structure endows the nanoparticles with extremely high rigidity modulus, making them incompressible and non-deformable physical "reinforcing points" in the ABS matrix, effectively hindering the long-term relaxation and plastic slip of the SAN phase molecular chains, thereby significantly improving the overall modulus, hardness and creep resistance of the material. The shell is a random copolymer of poly(hydroxyethyl methacrylate-co-styrene). Among them, the styrene unit has excellent compatibility with the matrix SAN phase, ensuring that the particles are uniformly dispersed and well wetted by the matrix; while the hydroxyethyl methacrylate unit contributes highly reactive primary hydroxyl groups. These hydroxyl groups densely distributed on the particle surface are the core functional groups for subsequent covalent bonding with the isocyanate cross-linking agent, and are also the basis for forming a strong hydrogen bond network with other polar components in the system (such as grafting agents and nanofillers).

[0030] (2) Amphiphilic nanoscale polymer grafting agent: This component is a linear AB-type diblock copolymer precisely synthesized by atom transfer radical polymerization (ATRP) technology. Among them, block A is a hydrophobic polystyrene block, whose molecular chains achieve deep physical interlocking and anchoring with the SAN phase in the ABS matrix and the polystyrene core of the reactive core-shell assembly agent through segment entanglement, diffusion and hydrophobic interaction. Block B is a hydrophilic reactive polymethyl methacrylate block, whose side chains have a large number of highly reactive epoxy groups. This block copolymer plays a dual role in the system as a "general molecular bridge" and an "interfacial compatibilizer": its polystyrene block provides the binding force with the organic matrix, while the polymethyl methacrylate block, through the reactivity of the epoxy groups, becomes a chemical "bridge" connecting the inorganic nanofiller and the organic matrix and participating in the overall cross-linking network.

[0031] (3) Hexamethylene diisocyanate trimer: As the core crosslinking agent and reaction hub of the system, its molecular structure contains three highly symmetrical isocyanate groups. Within the temperature window of material melting processing (175-200℃), these -NCO groups exhibit extremely strong reactivity and can efficiently undergo addition polymerization reactions with various functional groups containing active hydrogen in the system. Its main reaction targets include: forming urethane bonds with hydroxyl groups on the shell of reactive core-shell assemblies; forming urea bonds with amino groups at the ends of amino-terminated polydimethylsiloxanes; and reacting with hydroxyl groups generated after ring opening of the epoxy groups of the polymethyl methacrylate block in the amphiphilic nanoscale polymer grafting agent under specific conditions. These reactions occur in situ during processing, constructing a three-dimensional covalent crosslinking network that runs through the entire material.

[0032] (4) Ammonium-terminated polydimethylsiloxane: Its molecule is a linear polydimethylsiloxane with primary amino groups at both ends. The compliant siloxane backbone (-Si-O-Si-) has extremely low rotational barriers and surface energy. The terminal amino groups are key to its functionality: on the one hand, as highly active functional groups, amino groups directly participate in the cross-linking reaction of hexamethylene diisocyanate trimers, and chemically anchor themselves in the three-dimensional network by generating urea bonds, thus avoiding the precipitation problem of small molecule migratory agents; on the other hand, driven by the thermodynamics of processing, the siloxane segments that are not completely anchored will migrate to the material surface. This migration process is regulated by the dynamic balance of hydrogen bonding between amino groups and polar groups of the matrix (such as cyano groups in ABS), and finally forms a gradient distribution of gradually increasing siloxane concentration on the material surface, achieving a "dynamic gradient surface" with internal rigidity and external toughness and extremely low surface energy.

[0033] (5) Organized montmorillonite: This is a layered silicate mineral. Through ion exchange reactions, sodium and calcium ions between its layers are replaced by long-chain alkyl quaternary ammonium salt cations (such as dioctadecyl dimethyl ammonium chloride). This process is called organification. Organization treatment significantly expands the interlayer spacing of montmorillonite and changes its surface from hydrophilic to oleophilic, thereby achieving good compatibility with the polymer matrix. Its core function lies in its nanosheet structure. When it reaches the exfoliation or intercalation state in the matrix, it can form a huge two-dimensional spatial barrier to the movement of polymer molecular chains, effectively extending the diffusion path of gases and small molecules and restricting the movement of chain segments, thereby simultaneously improving the rigidity, heat distortion temperature and dimensional stability of the material.

[0034] (6) Porous silica nanospheres loaded with hindered amine light stabilizers: This component consists of uniform nanoscale pores (pore size 5-8 nm) and high specific surface area (>400 m²). 2 The process involves loading high-molecular-weight polymeric hindered amine light stabilizers (such as light stabilizer 944) into pores via physical impregnation and adsorption, followed by gentle end-capping of the pores with a silane coupling agent (such as γ-aminopropyltriethoxysilane). The silica spheres themselves are rigid nanoparticles, serving a reinforcing function. Their innovation lies in their "carrier-slow-release" function: the porous structure acts as a nano-"reservoir," physically fixing the light stabilizer; the partially end-capped pores create diffusion barriers, allowing the light stabilizer to be slowly and controllably released into the matrix according to the intensity of environmental aging. This achieves long-term, intelligent capture of UV-induced free radicals, solving the problems of easy migration, volatilization, and early consumption of light stabilizers in traditional direct addition methods.

[0035] (7) Carbon nanotubes: One-dimensional tubular carbon nanomaterials, formed by rolling up single or multiple layers of graphene sheets. Their extremely high aspect ratio (typically >100), excellent axial tensile strength and modulus enable them to act as bridging and reinforcing "micro-steel bars" in polymer matrices. When subjected to external forces, carbon nanotubes can effectively initiate and transfer stress, and consume a large amount of energy through their own stretching, slippage and even eventual fracture processes, thereby simultaneously improving the strength and toughness of the material. In addition, their high thermal conductivity also helps to dissipate heat evenly during processing and reduce internal stress.

[0036] (8) Polymethyl methacrylate: The ester groups on its molecular chain have similar polarity to the cyano groups in the SAN phase of ABS, resulting in good compatibility. Adding a small amount of polymethyl methacrylate can further improve the compatibility of the entire multiphase system and contribute to the material modulus due to its high rigidity.

[0037] (9) Lanthanum benzoate: A rare earth organic complex. The benzene ring structure in its molecule can generate π-π stacking interactions with the benzene rings in ABS resin and polystyrene blocks, potentially acting as a heterogeneous nucleation site and refining the phase region. More importantly, rare earth ions (La... 3+ It has a unique electronic layer structure that can effectively absorb ultraviolet light and dissipate its energy as harmless heat, providing the first line of ultraviolet shielding.

[0038] (10) Composite antioxidant: Composed of the primary antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and the secondary antioxidant tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:(1-2). Antioxidant 1010 acts as a hydrogen donor, which can capture alkyl radicals and alkoxy radicals generated during oxidation in a long-term and efficient manner, interrupting the chain oxidation reaction. Antioxidant 168 acts as a hydroperoxide decomposer, which rapidly decomposes the hydroperoxides generated by polymer oxidation into stable products at high processing temperatures, preventing them from decomposing and generating new free radicals. The two complement each other through their mechanisms, forming a synergistic thermo-oxidative stabilization system covering the entire cycle of processing (short-term) and service (long-term).

[0039] Meanwhile, the superior performance of this material stems from the multi-layered, integrated "structured network" constructed from the bottom up during processing through multiple interactions among the aforementioned components, including covalent bonds, hydrogen bonds, physical entanglement, and steric effects. Its synergistic effect is manifested at the following levels: (1) Covalent cross-linked network as a supporting framework: Hexamethylene diisocyanate trimer serves as the convergence center of chemical reactions. Its isocyanate groups react with the hydroxyl groups of the reactive core-shell assemblies, the amino groups of the amino-terminated polydimethylsiloxanes, and the hydroxyl groups that may be generated by the amphiphilic nanoscale polymer grafting agents, constructing a three-dimensional covalent network in the matrix mainly composed of urethane bonds and urea bonds. This network chemically bonds the core-shell assemblies, which act as "rigid points," the siloxanes, which act as "flexible segments," and the grafting agents, which act as "interface bridges," into a whole. Its core synergistic effect is that when the material is subjected to stress, the stress can be efficiently transferred from the continuous phase matrix to the rigid nanoparticles through this covalent network, forcing the particles to bear the main load; at the same time, the moderate flexibility of the network can dissipate energy through bond angle rotation and chain segment movement. This "rigid and flexible" covalent framework is the structural basis for the material to achieve high strength, high toughness, and extremely low coefficient of thermal expansion (because it greatly restricts the thermal freedom of polymer chains).

[0040] (2) Synergistic effect of interface strengthening and nano-reinforcement mediated by "molecular bridge": Amphiphilic nanoscale polymer grafting agents are key to achieving high-performance composites of inorganic nanofillers and organic matrices. The polystyrene blocks are anchored to the matrix, while the epoxy groups of the polyglycidyl methacrylate blocks can undergo ring-opening reactions or form strong hydrogen bonds with the silanol groups on the edges and surfaces of organo-modified montmorillonite sheets and the silanol groups on the surface of porous silica nanospheres, and can also physically entangle with the walls of carbon nanotubes. This is equivalent to establishing a strong chemical and physical "connection point" between the nanofiller and the polymer.

[0041] In particular, the organic montmorillonite, porous silica nanospheres, and carbon nanotubes form a unique "sheet-point-line" three-dimensional spatial interlocking and synergistic enhancement mechanism: the organic montmorillonite sheets, acting as two-dimensional barrier units, are dispersed in the matrix, dividing and restricting the movement space of polymer chain segments. The porous silica nanospheres, as zero-dimensional rigid nodes, effectively prevent the recombination of montmorillonite sheets and break up any entangled clusters that carbon nanotubes may form. The carbon nanotubes, as one-dimensional linear units, with their high aspect ratio, can interpenetrate between montmorillonite sheets and connect multiple silica nanospheres, much like adding "steel bars" to building materials.

[0042] Provided that the three components are well dispersed by the grafting agent and their interfaces are modified, they can initially form an interpenetrating and interlocking nanoscale reinforcing framework in the matrix. This framework interpenetrates and supports the aforementioned polymer covalent cross-linked network, jointly bearing the load. Montmorillonite sheets provide in-plane rigidity and barrier properties, silica nanospheres provide point-like reinforcement and load functional additives, and carbon nanotubes provide axial reinforcement and toughening. The three components work synergistically to achieve a comprehensive and nonlinear improvement in the material's modulus, strength, toughness, and dimensional stability.

[0043] (3) Synergistic Construction of Smart Surface by Chemical Anchoring and Dynamic Migration: The mechanism of action of amino-terminated polydimethylsiloxane is a prime example of dynamic synergy. Its amino group achieves a certain degree of chemical anchoring by participating in the cross-linking reaction of isocyanate, which avoids the disadvantages of easy precipitation and poor abrasion resistance when used as a simple external lubricant. At the same time, unreacted or only hydrogen-bonded siloxane segments migrate to the low-polarity material-air interface under entropy drive. This migration process becomes controllable due to the constraints of chemical anchoring points and physical hydrogen bonds, ultimately forming a gradient transition layer with continuously increasing siloxane concentration from the inside to the outside on the surface. The polydimethylsiloxane chains enriched on the outside of this layer significantly reduce the surface energy of the material, giving it excellent release properties, abrasion resistance, and hydrophobicity, while the chemical connection on the inside ensures the durability of this functional layer.

[0044] (4) Multi-level, multi-mechanism synergistic stabilization protection: The long-term durability of the material is guaranteed by a well-defined and collaborative stabilization system. Instantaneous protection during processing: This is mainly undertaken by the auxiliary antioxidant (antioxidant 168) in the composite antioxidant, which rapidly decomposes hydrogen peroxide at the high temperature of melt extrusion to prevent processing degradation. Long-term thermo-oxidative protection: This is provided by the main antioxidant (antioxidant 1010) in the composite antioxidant, which provides continuous free radical scavenging capability. Ultraviolet protection: This constitutes three lines of defense. The first line is shielded by lanthanum benzoate through the absorption of ultraviolet light. The second line is the hindered amine light stabilizer slowly released from the porous silica nanospheres, which continuously captures free radicals excited by ultraviolet light penetrating into the material. The third line is the dense cross-linked network and nanofiller barrier constructed by the system, which itself also hinders the penetration of oxygen and ultraviolet light. These three elements, from "blocking" and "quenching" to "repairing", constitute a three-dimensional long-term weather-resistant protection system.

[0045] In summary, the ABS material system used for camera housings is a highly integrated system based on deep molecular structure design and precise interface engineering. It is not a simple superposition of the functions of its components, but rather a covalently cross-linked main network constructed through in-situ polymerization initiated by hexamethylene diisocyanate trimer, which is interconnected and synergistically reinforced by a three-dimensional nano-reinforcing framework consisting of a sheet-dot-line structure mediated by amphiphilic nanoscale polymer grafting agents, organo-montmorillonite, porous silica nanospheres, and carbon nanotubes. Simultaneously, amino-terminated polydimethylsiloxane constructs a dynamic gradient functional layer on the surface through a balance between chemical anchoring and physical migration, while composite antioxidants, lanthanum benzoate, and supported light stabilizers constitute a multi-mechanism synergistic stabilization system.

[0046] These synergistic effects, designed at the molecular scale, ultimately achieve a breakthrough balance of material properties at the macroscopic scale: extremely high dimensional stability and a low coefficient of thermal expansion to meet precision assembly requirements, an excellent balance of rigidity and toughness to resist impact and deformation, and superior long-term weather resistance to maintain appearance and performance. This makes it fully meet the stringent performance requirements of high-end camera housings.

[0047] In some embodiments, the preparation method of the reactive core-shell assembling agent includes the following steps: S101. Under inert gas protection, styrene monomer, crosslinking agent divinylbenzene and initiator azobisisobutyronitrile are dissolved in an organic solvent and dispersed polymerized at 70-85°C for 4-8 hours. After centrifugation, washing and drying, crosslinked polystyrene nanospheres with a particle size of 80-120 nm are obtained. S102. Cross-linked polystyrene nanospheres are dispersed in an alcohol-water mixed solvent containing polyvinylpyrrolidone dispersant, and a uniform dispersion is formed under the combined action of stirring and ultrasound. S103. Hydroxyethyl methacrylate monomer, styrene monomer and initiator azobisisobutyronitrile are added sequentially to the dispersion and reacted at 75-80℃ for 5-10 hours to form a poly(hydroxyethyl methacrylate-co-styrene) copolymer shell on the hard core surface through graft copolymerization. After the reaction is completed, the reactant core-shell assembly agent is obtained by centrifugation, washing and vacuum drying.

[0048] In some embodiments, in step S101, the mass ratio of styrene monomer, crosslinking agent divinylbenzene, and initiator azobisisobutyronitrile is 100:(2-10):(0.5-2.0); In step S102, the mass of the polyvinylpyrrolidone dispersant is 5% to 15% of the mass of the cross-linked polystyrene nanospheres; In step S103, the mass ratio of hydroxyethyl methacrylate monomer to styrene monomer is (6-9):(1-4); the total mass of hydroxyethyl methacrylate monomer and styrene monomer is in the ratio of the mass of cross-linked polystyrene nanospheres to 0.5:1-2:1; and the mass of the initiator azobisisobutyronitrile is 0.5-2.0% of the total mass of hydroxyethyl methacrylate monomer and styrene monomer.

[0049] Step S101: Preparation of Crosslinked Polystyrene (PS) Hard Cores. This step aims to prepare monodisperse, uniformly sized rigid nanoparticles as "seeds" for subsequent shell growth through dispersion polymerization. Styrene monomers undergo free radical polymerization under the thermal decomposition of the oil-soluble initiator azobisisobutyronitrile (AIBN). The added crosslinking agent, divinylbenzene, contains two vinyl groups, which can form covalent bonds between multiple polystyrene chains, constructing a three-dimensional network structure, thereby endowing the microspheres with excellent rigidity, thermal stability, and incompressibility.

[0050] Styrene:divinylbenzene:AIBN = 100:(2-10):(0.5-2.0): This ratio is crucial for controlling the hard core properties. 2-10 parts of divinylbenzene ensure a suitable crosslinking density: sufficient crosslinking guarantees core rigidity, while excessive crosslinking may affect subsequent shell grafting. 0.5-2.0 parts of AIBN provide a suitable free radical concentration to control the polymerization rate and molecular weight, thereby obtaining a target particle size of 80-120 nm. 70-85℃ is the suitable temperature range for AIBN decomposition to generate free radicals, ensuring stable polymerization. A reaction time of 4-8 hours ensures complete monomer conversion.

[0051] Step S102: The pre-dispersion step of the hard core creates a uniform and stable reaction site for the shell graft copolymerization in the second step. Transferring the hydrophobic cross-linked PS nanospheres from the organic phase to the alcohol-water mixed solvent requires the use of water-soluble polyvinylpyrrolidone (PVP) as a dispersant. PVP adsorbs onto the surface of the PS nanospheres through its hydrophobic segments, while its hydrophilic segments extend into the aqueous phase, forming steric hindrance and preventing nanoparticle aggregation. Stirring and ultrasonication work together to break up soft agglomerates, achieving monodispersion of the nanospheres in the medium.

[0052] The amount of PVP used is 5% to 15% of the mass of PS microspheres: this ratio ensures that PVP is sufficient to completely cover the surface of all nanospheres, forming an effective steric stabilizing layer. The polar environment of the alcohol-water mixed solvent (usually an ethanol / water system) is not only conducive to the dissolution and function of PVP, but also provides a good medium for the subsequent polymerization of the highly hydrophilic hydroxyethyl methacrylate monomer.

[0053] Step S103: The assembly step of the core-shell structure particles is the process of constructing the functionalized shell. A reactive copolymer shell is grown on the surface of the PS hard core through graft copolymerization. Hydroxyethyl methacrylate and styrene monomers undergo free radical copolymerization on and near the PS core surface under the action of the initiator AIBN. Due to the presence of the PS core and interfacial interactions, some polymer chains are chemically anchored to the core surface through chain transfer or grafting reactions, forming a core-shell structure bonded by chemical bonds.

[0054] HEMA:St = (6-9): (1-4): This ratio directly determines the chemical composition and reactivity of the shell. A higher HEMA content (60%-90%) ensures that the shell is rich in hydroxyl groups, providing a high density of reaction sites for the subsequent crosslinking reaction with isocyanates. The addition of a small amount of styrene helps improve the compatibility of the shell with the PS core and the SAN phase of the ABS matrix.

[0055] (HEMA+St) total mass:PS core mass = 0.5:1 to 2:1: This ratio precisely controls the shell thickness. If the ratio is too low, the shell will be too thin and the function will be insufficient; if the ratio is too high, homopolymer side reactions are likely to occur, and particle dispersion may be affected. This range can effectively control the shell thickness in the tens of nanometers.

[0056] The AIBN dosage is 0.5%–2.0% of the total monomer mass: this initiator concentration is used to control the rate and molecular weight of shell polymerization, ensuring effective growth of grafted chains while avoiding explosive polymerization. A reaction temperature of 75-80℃ is matched with the initiator half-life to ensure stable shell polymerization.

[0057] In some embodiments, the preparation method of porous silica nanospheres loaded with hindered amine light stabilizers includes the following steps: S201. Porous silica nanospheres are immersed in an organic solvent solution containing hindered amine light stabilizer and ultrasonically treated at 40-60℃ for 1-3 hours. After solid-liquid separation, a primary powder loaded with hindered amine light stabilizer is obtained. S202 Under vacuum conditions, the primary powder is heat-treated at 80-100℃ for 2-4 hours, then a silane coupling agent is added, and the mixture is reacted at 100-120℃ for 1-2 hours to obtain porous silica nanospheres loaded with hindered amine light stabilizers.

[0058] In some embodiments, in step S201, the mass ratio of porous silica nanospheres to hindered amine light stabilizer is 10:(2-5), and the hindered amine light stabilizer is light stabilizer UV-944. In step S202, the mass of the silane coupling agent is 1-5% of the initial mass of the porous silica nanospheres, and the silane coupling agent is γ-aminopropyltriethoxysilane.

[0059] Step S201: The impregnation and loading step utilizes the high specific surface area and nanoscale pores of porous silica nanospheres to load hindered amine light stabilizer molecules through physical adsorption (capillary action, surface energy driven). Ultrasonic treatment utilizes the powerful impact flow generated by cavitation effect to significantly promote the diffusion and filling of the light stabilizer solution into the deep pores, achieving efficient and rapid loading.

[0060] SiO2 spheres:HALS(UV-944) = 10:(2~5): This loading ratio is calculated based on the pore volume of porous silica and the molecular size of the light stabilizer. A loading of 20%-50% maximizes the amount of light stabilizer carried, ensuring that the pores are not completely blocked, providing a sufficient "ammunition depot" for long-lasting sustained release. The ultrasonic temperature of 40~60℃ moderately improves molecular mobility, which is beneficial to loading, while avoiding the thermal decomposition of the light stabilizer.

[0061] Step S202: The heat treatment and silane coupling agent end-capping step has two functions: 1) Heat treatment: Gentle heating under vacuum aims to completely remove the organic solvent remaining in the pores after impregnation, and to further relax and fix the adsorbed HALS molecules on the inner wall of the pores, forming a more stable physical adsorption state. 2) Silane coupling agent reaction: The added γ-aminopropyltriethoxysilane first hydrolyzes its ethoxy group to generate silanol groups, which then undergo a dehydration condensation reaction with the silanol groups on the surface of the silica nanospheres and at the pore openings to form strong Si-O-Si covalent bonds. This process achieves partial chemical end-capping of the pore inlet.

[0062] The KH-550 dosage is 1% to 5% of the initial mass of the SiO2 spheres: this dosage aims to achieve partial, rather than complete, orifice sealing. Too low a sealing degree may lead to excessively rapid HALS release; sealing at this ratio can create a certain diffusion barrier at the orifice inlet, thereby changing the HALS release mode from rapid escape to controlled slow release, greatly extending the effective protection time. 100–120℃ is the suitable temperature for the condensation reaction between the silane coupling agent and the silica surface, and 1–2 hours is sufficient to ensure a complete reaction.

[0063] In some embodiments, the preparation method of the amphiphilic nanoscale polymer grafting agent includes the following steps: S301. Under inert gas protection, styrene monomer, ethyl α-bromoisobutyrate initiator, and a catalytic system composed of cuprous chloride and N,N,N',N'',N''-pentamethyldiethylenetriamine are dissolved in an organic solvent and subjected to atom transfer radical polymerization at 100-120°C for 4-8 hours. After the reaction, the mixture is precipitated, washed, and vacuum dried to obtain a polystyrene macromolecular initiator with bromine atoms at the end. S302. The polystyrene macromolecular initiator is redissolved in an organic solvent, and glycidyl methacrylate monomer is added. Under the action of a catalytic system, the atom transfer radical polymerization reaction is continued at 80-100℃ for 6-12 hours. After the reaction is completed, the mixture is precipitated, washed and vacuum dried to obtain an amphiphilic nanoscale polymer grafting agent.

[0064] In some embodiments, in step S301, the molar ratio of styrene monomer to initiator ethyl α-bromoisobutyrate is (80-200):1; the molar ratio of cuprous chloride to N,N,N',N'',N''-pentamethyldiethylenetriamine is 1:(1-1.5).

[0065] In step S302, the molar ratio of glycidyl methacrylate monomer to polystyrene macromolecular initiator is (30-100):1.

[0066] Step S301: The synthesis of the first block copolymer (polystyrene) is the first step in the synthesis of block copolymers using atom transfer radical polymerization. Its purpose is to prepare a polystyrene macromolecular initiator with a controllable molecular weight and an active halogen atom (bromine) at the end. The reaction uses ethyl α-bromoisobutyrate as the initiator, whose structure mimics the structure at the end of the growing chain, enabling rapid and synchronous initiation. The catalytic system composed of cuprous chloride and pentamethyldiethylenetriamine establishes a dynamic equilibrium between the active species (growing radicals) and the dormant species (polymer chains with bromine at the end) through a reversible redox reaction. This is crucial for achieving controllable polymerization (controllable molecular weight, narrow distribution, and high end activity).

[0067] St:EBiB=(80~200):1: This is the core formula for controlling polymer molecular weight in ATRP. This molar ratio directly presets the degree of polymerization of the target polystyrene block (approximately 80~200), thus precisely controlling its molecular weight. 100~120℃ is a commonly used temperature for styrene ATRP polymerization, balancing polymerization rate and controllability.

[0068] CuCl:PMDETA=1:(1~1.5): This ratio ensures that the ligand PMDETA fully complexes the monovalent copper catalyst to form a highly active catalytic complex, maintaining an efficient activation-deactivation balance, which is a prerequisite for the polymerization reaction to maintain its "active" characteristics.

[0069] Step S302: The graft polymerization step of the second block (polyglycidyl methacrylate) utilizes the reactivation of the carbon-bromine bond at the end of the PS-Br macromolecular initiator synthesized in the previous step under Cu / PMDETA catalysis to initiate the ATRP polymerization of the second monomer glycidyl methacrylate, thereby growing the second block and finally obtaining a well-defined PS-b-PGMA diblock copolymer.

[0070] GMA:PS-Br = (30-100):1: This molar ratio is used to predetermine the chain length of the second block PGMA. A degree of polymerization of 30-100 gives the PGMA blocks sufficient length, making them rich in epoxy functional groups. These epoxy groups are key to the grafting agent acting as a "molecular bridge," and can react with hydroxyl groups on the surface of nanofillers, amino groups in amino-terminated silicone oils, and isocyanates to achieve interfacial reinforcement. The slightly lower temperature of 80-100℃ suits the polymerization characteristics of the GMA monomer and helps protect the epoxy groups from ring-opening side reactions during polymerization.

[0071] In some embodiments, the composite antioxidant consists of a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and the secondary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The mass ratio of primary antioxidant to secondary antioxidant is 1:(1-2).

[0072] Primary antioxidant : Secondary antioxidant = 1 : (1-2): This mass ratio is a highly efficient synergistic ratio verified through extensive practical experience. The proportion of secondary antioxidant is slightly higher, emphasizing its primary importance in rapidly decomposing hydroperoxides during high-temperature processing, creating a "clean" environment for the primary antioxidant to exert its long-term effect. Together, they form a full-cycle stabilization system covering both instantaneous high-temperature protection and long-term thermo-oxidative aging protection during processing.

[0073] Figure 1 This is a schematic flowchart illustrating a method for preparing ABS material for a camera housing, as provided in an embodiment of this application.

[0074] Based on a general inventive concept, such as Figure 1 As shown, this application provides a method for preparing ABS material for a camera housing according to any one of the first aspects, the method comprising the following steps: S1. Organic montmorillonite, porous silica nanospheres loaded with hindered amine light stabilizer, carbon nanotubes and some ABS resin powder are dry mixed in a high-speed mixer to obtain nanofiller premix. S2. Polymethyl methacrylate, amino-terminated polydimethylsiloxane, lanthanum benzoate, composite antioxidant and the remaining ABS resin powder are mixed in a high-speed mixer to obtain matrix functional premix. S3. The matrix functional premix, nanofiller premix, reactive core-shell assembly agent, and amphiphilic nanoscale polymer grafting agent are fed into the main feed hopper of a twin-screw extruder. Hexamethylene diisocyanate trimer is injected into the middle and rear of the melting section through a side-line liquid injection pump. Under the action of screw shearing and vacuum degassing, the mixture is melt-blended and reacted. After extrusion, water cooling, and pelletizing, modified ABS granules are obtained. S4. The modified ABS granules are dried by blowing at 75-85℃ for 3-5 hours to obtain ABS material for camera housing that can be used for injection molding.

[0075] In some embodiments, in step S1, the mass of a portion of the ABS resin powder is 20-30% of the total mass of the ABS resin powder; In step S2, the temperature of each section of the twin-screw extruder is 175–200°C, the screw length-to-diameter ratio is 40:1–48:1, and the screw speed is 200–350 rpm. The vacuum level of the vacuum exhaust is not lower than -0.08MPa.

[0076] It should be noted that the core design idea of ​​this preparation method is to solve the problem of uniform dispersion and interfacial reaction in multi-component, multi-scale (from nanofillers to macromolecules) composite systems through the strategy of "stepwise pre-dispersion-reactive extrusion", and finally build a stable synergistic network in situ during the processing.

[0077] Step S1: The preparation of the nanofiller premix aims to preemptively address the challenge of easy agglomeration of nanofillers such as organo-modified montmorillonite, supported silica nanospheres, and carbon nanotubes due to their large specific surface area and high surface energy. These nanofillers are rapidly dry-mixed with 20%–30% ABS resin powder by mass. The resin powder acts as a carrier, using mechanical shear force to initially break up the soft agglomerates of the fillers and allow the resin powder to adhere to the filler surface. This process is equivalent to preparing a high-concentration "nanofiller masterbatch." The amount of ABS resin used is sufficient to initially encapsulate and separate the individual nanofiller particles, laying the foundation for subsequent nanoscale dispersion in the melt, while avoiding problems such as uneven dispersion and localized stress concentration caused by directly adding the filler to the main melt.

[0078] Step S2: The purpose of the premixing step is to achieve physical homogeneity by pre-mixing functional small molecules or polymer additives such as polymethyl methacrylate (PMMA), amino-terminated polydimethylsiloxane (PDMS), lanthanum benzoate, and composite antioxidants with the remaining ABS resin powder. PMMA acts as a compatibilizer, and its pre-dispersion helps improve overall compatibility; liquid additives such as PDMS are adsorbed onto the surface of the resin powder, preventing agglomeration or loss during subsequent feeding. This premixing ensures that these functional components, added in small quantities but playing a crucial role, achieve macroscopic homogeneity before entering the extruder, which is an important guarantee for the uniformity of the final material properties.

[0079] Step S3: The melt blending and reactive extrusion step is the core of the entire material forming and performance determination process. It simultaneously completes physical melt blending and multiple in-situ chemical reactions.

[0080] Physical blending and dispersion: The premix of S1 and S2, along with the reactive core-shell assembling agent and the amphiphilic nanoscale polymer grafting agent, are fed into the twin-screw extruder through the main feed inlet. The ABS resin matrix is ​​fully plasticized at a melt temperature of 175–200°C. This temperature range is precisely set: the lower limit of 175°C ensures complete melting of ABS and all polymer components, providing the necessary molecular chain mobility; the upper limit of 200°C prevents significant thermal degradation of the ABS resin and heat-sensitive components (such as antioxidants).

[0081] Shearing and Mixing: The screw length-to-diameter ratio of 40:1 to 48:1 provides a sufficiently long conveying, compression, mixing, and homogenization section, ensuring that the material undergoes sufficient residence time and mixing process. The moderate shear field generated by the screw speed of 200 to 350 rpm can further strip the agglomerates of nanofillers (especially montmorillonite) to achieve nanoscale dispersion; on the other hand, it can also highly homogenize the components of the melt.

[0082] In-situ chemical reaction: Hexamethylene diisocyanate trimer is precisely injected into the rear of the melting section via a side-stream liquid injection pump. At this point, the solid material is completely melted and initially homogenized. After the HDI trimer is injected, its highly reactive isocyanate groups rapidly react with the uniformly distributed active sites in the melt. This reaction mainly involves reactions with the hydroxyl groups of the shell of the reactive core-shell assembly agent, the epoxy groups (or their ring-opening hydroxyl groups) of the amphiphilic nanoscale polymer grafting agent, and the amino groups of the amino-terminated polydimethylsiloxane, generating urethane bonds, urea bonds, etc. This process takes place throughout the melt under continuous mixing by the screw, constructing a covalent cross-linked network in situ and chemically bonding all functional components to this network.

[0083] Deviation and densification: Vacuum venting (vacuum degree not lower than -0.08MPa) effectively removes moisture, air, residual monomers, and some reaction byproducts (such as trace amounts of carbon dioxide that may be generated) from the melt. This prevents bubbles or silver streaks from forming in the final product and improves the material's density, mechanical strength, and appearance quality.

[0084] Step S4: The modified ABS granules obtained by water-cooling pelletizing will absorb trace amounts of moisture on their surface. ABS material has a certain degree of hygroscopicity, and residual moisture will vaporize under the high temperature environment of subsequent injection molding, leading to defects such as silver streaks and bubbles on the surface of the product. Therefore, forced-air drying at 75-85℃ for 3-5 hours is to reduce the moisture content of the granules to the extremely low level required by the injection molding process (usually below 0.05%), thereby ensuring that the final injection-molded camera housing has excellent appearance and internal quality.

[0085] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0086] Example 1 This embodiment provides an ABS material for a camera housing, which is composed of the following raw materials: ABS resin (CAS: 9003-56-9, model: Chimei PA-758): 80 parts; reactive core-shell assembly agent: 10 parts; polymethyl methacrylate (CAS: 9011-14-7): 3 parts; amino-terminated polydimethylsiloxane (CAS: 97917-34-5): 2 parts; organomodified montmorillonite (CAS: 1318-93-0): 3 parts; and a load-resistance-dependent material. Porous silica nanospheres with amine light stabilizer: 2 parts; carbon nanotubes (CAS: 308068-56-6): 1.0 part; amphiphilic nanoscale polymer grafting agent: 2.0 parts; lanthanum benzoate: 0.4 parts; composite antioxidant: 0.4 parts (composed of the main antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and the auxiliary antioxidant tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1.5); hexamethylene diisocyanate trimer: 0.3 parts.

[0087] The preparation method of the reactive core-shell assembly agent includes the following steps: S101. Under nitrogen protection, styrene monomer, crosslinking agent divinylbenzene, and initiator azobisisobutyronitrile were dissolved in toluene at a mass ratio of 100:5:1.2, and a dispersion polymerization reaction was carried out at 80°C for 6 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain crosslinked polystyrene nanospheres with a particle size of approximately 100 nm.

[0088] S102. The obtained cross-linked polystyrene nanospheres are dispersed in an ethanol / water mixed solvent (volume ratio 2:1) containing polyvinylpyrrolidone (PVP), with the amount of PVP being 10% of the mass of the microspheres. A uniform dispersion is formed under the combined action of stirring and ultrasound.

[0089] S103. Hydroxyethyl methacrylate monomer (CAS No. 868-77-9), styrene monomer, and initiator azobisisobutyronitrile (AIBN) were added sequentially to the dispersion. The mass ratio of hydroxyethyl methacrylate to styrene monomer was 8:2; the mass ratio of the total mass of the two monomers to the mass of the cross-linked polystyrene nanospheres was 1.2:1; and the amount of AIBN was 1.0% of the total monomer mass. The reaction was carried out at 78℃ for 8 hours. After the reaction, the mixture was centrifuged, washed, and vacuum dried to obtain the reactive core-shell assembly agent.

[0090] The preparation method of porous silica nanospheres loaded with hindered amine light stabilizers includes the following steps: S201. Porous silica nanospheres (source: Suzhou Nanobiotechnology Co., Ltd.) were impregnated in an acetone solution containing the light stabilizer UV-944, wherein the mass ratio of silica nanospheres to UV-944 was 10:3. The mixture was ultrasonically treated at 50°C for 2 hours, and then filtered and dried to obtain a primary powder.

[0091] S202. Under vacuum conditions, the primary powder was heat-treated at 90°C for 3 hours. Then, γ-aminopropyltriethoxysilane (KH-550), a silane coupling agent accounting for 3% of the initial mass of the silica nanospheres, was added, and the mixture was reacted at 110°C for 1.5 hours to obtain porous silica nanospheres loaded with hindered amine light stabilizers.

[0092] The preparation method of the amphiphilic nanoscale polymer grafting agent includes the following steps: S301. Under argon protection, styrene monomer and initiator ethyl α-bromoisobutyrate (ATRP initiator, CAS No. 600-00-0) at a molar ratio of 150:1, along with catalyst cuprous chloride and ligand N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA, CAS No. 3030-47-5) at a molar ratio of 1:1.2, were dissolved in toluene and subjected to atom transfer radical polymerization at 110°C for 6 hours. After the reaction, the mixture was precipitated with methanol, washed, and vacuum dried to obtain a polystyrene macromolecular initiator with bromine atoms at the end.

[0093] S302. The above-mentioned polystyrene macromolecular initiator is redissolved in toluene, and glycidyl methacrylate monomer is added at a molar ratio of 60:1 to the polystyrene macromolecular initiator. Cuprous chloride and PMDETA are added in the same molar amounts as in step S301, and the reaction is continued at 90°C for 10 hours. After the reaction is completed, the mixture is precipitated, washed, and vacuum dried to obtain an amphiphilic nanoscale polymer grafting agent.

[0094] Based on the above-mentioned raw material composition of ABS material, this embodiment also provides a method for preparing ABS material, which includes the following steps: S1. Organic montmorillonite, porous silica nanospheres loaded with hindered amine light stabilizer, carbon nanotubes, and ABS resin powder accounting for 25% of the total mass are dry-mixed in a high-speed mixer for 5 minutes to obtain a nanofiller premix.

[0095] S2. Mix polymethyl methacrylate, amino-terminated polydimethylsiloxane, lanthanum benzoate, composite antioxidant and the remaining 75% ABS resin powder in a high-speed mixer for 5 minutes to obtain matrix functional premix.

[0096] S3. The matrix functional premix, nanofiller premix, reactive core-shell assembling agent, and amphiphilic nanoscale polymer grafting agent are all fed into the main feed hopper of the twin-screw extruder. Hexamethylene diisocyanate trimer is injected via a side-stream liquid injection pump into the rear section of the melt section (barrel temperature zone 190℃). The temperatures of each section of the twin-screw extruder are controlled as follows: Zone 1 (feeding section): 175℃; Zone 2 (melting section): 180℃; Zone 3 (mixing section): 185℃; Zone 4 (homogenization section): 190℃; Zone 5 (discharge section): 195℃. The screw length-to-diameter ratio is 44:1, the screw speed is 280 rpm, and vacuum degassing (vacuum degree -0.09 MPa) is performed. After melt blending and reaction, the material is extruded, water-cooled, and pelletized to obtain modified ABS granules.

[0097] S4. The obtained modified ABS granules are dried in a forced-air dryer at 80°C for 4 hours to obtain ABS material suitable for injection molding for camera housings.

[0098] Figure 2 A physical image of the camera housing made from the ABS material of Example 1, provided for this application. Figure 2 It can be seen that the camera housing is fully formed and has a regular structure, without defects such as shrinkage marks, flash, bubbles or missing materials.

[0099] Example 2 This embodiment provides an ABS material for a camera housing, which is composed of the following raw materials: ABS resin: 75 parts, reactive core-shell assembly agent: 8 parts, polymethyl methacrylate: 2 parts, amino-terminated polydimethylsiloxane: 1 part, organo-modified montmorillonite: 2 parts, porous silica nanospheres loaded with hindered amine light stabilizer: 1 part, carbon nanotubes: 0.5 parts, amphiphilic nanoscale polymer grafting agent: 1.0 part, lanthanum benzoate: 0.3 parts, composite antioxidant: 0.3 parts (composed of the main antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and the auxiliary antioxidant tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1), and hexamethylene diisocyanate trimer: 0.1 parts.

[0100] The preparation method of the reactive core-shell assembly agent includes the following steps: S101. Under nitrogen protection, styrene monomer, crosslinking agent divinylbenzene, and initiator azobisisobutyronitrile were dissolved in toluene at a mass ratio of 100:2:0.5, and a dispersion polymerization reaction was carried out at 70°C for 8 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain crosslinked polystyrene nanospheres with a particle size of approximately 80 nm.

[0101] S102. The obtained cross-linked polystyrene nanospheres are dispersed in an ethanol / water mixed solvent containing polyvinylpyrrolidone (PVP), with the amount of PVP being 5% of the mass of the microspheres. A uniform dispersion is formed under the combined action of stirring and ultrasound.

[0102] S103. Hydroxyethyl methacrylate monomer, styrene monomer, and initiator azobisisobutyronitrile (AIBN) are added sequentially to the dispersion. The mass ratio of hydroxyethyl methacrylate to styrene monomer is 6:4; the mass ratio of the total mass of the two monomers to the mass of the cross-linked polystyrene nanospheres is 0.5:1; and the amount of AIBN is 0.5% of the total monomer mass. The reaction is carried out at 75°C for 10 hours. After the reaction is complete, the mixture is centrifuged, washed, and vacuum dried to obtain the reactive core-shell assembly agent.

[0103] The preparation method of porous silica nanospheres loaded with hindered amine light stabilizers includes the following steps: S201. Porous silica nanospheres are impregnated in an acetone solution containing the light stabilizer UV-944, wherein the mass ratio of silica nanospheres to UV-944 is 10:2. The mixture is ultrasonically treated at 40°C for 3 hours, then filtered and dried to obtain a primary powder.

[0104] S202. Under vacuum conditions, the primary powder was heat-treated at 80°C for 4 hours. Then, 1% of the initial mass of the silica nanospheres was added as a silane coupling agent γ-aminopropyltriethoxysilane, and the mixture was reacted at 100°C for 2 hours to obtain porous silica nanospheres loaded with hindered amine light stabilizers.

[0105] The preparation method of the amphiphilic nanoscale polymer grafting agent includes the following steps: S301. Under argon protection, styrene monomer and initiator ethyl α-bromoisobutyrate at a molar ratio of 80:1, along with catalyst cuprous chloride and ligand pentamethyldiethylenetriamine at a molar ratio of 1:1, were dissolved in toluene and subjected to atom transfer radical polymerization at 100°C for 8 hours. After the reaction, the mixture was precipitated with methanol, washed, and vacuum dried to obtain a polystyrene macromolecular initiator with bromine atoms at the end.

[0106] S302. The above-mentioned polystyrene macromolecular initiator is redissolved in toluene, and glycidyl methacrylate monomer is added at a molar ratio of 30:1 to the polystyrene macromolecular initiator. Cuprous chloride and PMDETA are added in the same molar amounts as in step S301, and the reaction is continued at 80°C for 12 hours. After the reaction is completed, the mixture is precipitated, washed, and vacuum dried to obtain an amphiphilic nanoscale polymer grafting agent.

[0107] Based on the above-mentioned raw material composition of ABS material, this embodiment also provides a method for preparing ABS material, which includes the following steps: S1. Organic montmorillonite, porous silica nanospheres loaded with hindered amine light stabilizers, carbon nanotubes, and ABS resin powder accounting for 20% of the total mass are dry-mixed in a high-speed mixer for 5 minutes to obtain a nanofiller premix.

[0108] S2. Mix polymethyl methacrylate, amino-terminated polydimethylsiloxane, lanthanum benzoate, composite antioxidant and the remaining 80% ABS resin powder in a high-speed mixer for 5 minutes to obtain matrix functional premix.

[0109] S3. The matrix functional premix, nanofiller premix, reactive core-shell assembling agent, and amphiphilic nanoscale polymer grafting agent are all fed into the main feed hopper of the twin-screw extruder. Hexamethylene diisocyanate trimer is injected into the rear of the melt section via a side-stream liquid injection pump. The temperatures of each section of the twin-screw extruder are controlled as follows: Zone 1: 175℃, Zone 2: 178℃, Zone 3: 183℃, Zone 4: 188℃, Zone 5: 192℃; screw length-to-diameter ratio: 40:1; screw speed: 200 rpm; and vacuum degassing (vacuum degree -0.08 MPa). After melt blending and reaction, the material is extruded, water-cooled, and pelletized to obtain modified ABS granules.

[0110] S4. The obtained modified ABS granules are dried in a forced-air dryer at 75°C for 5 hours to obtain ABS material suitable for injection molding for camera housings.

[0111] Example 3 This embodiment provides an ABS material for a camera housing, which is composed of the following raw materials: ABS resin: 85 parts, reactive core-shell assembly agent: 12 parts, polymethyl methacrylate: 4 parts, amino-terminated polydimethylsiloxane: 3 parts, organo-modified montmorillonite: 4 parts, porous silica nanospheres loaded with hindered amine light stabilizer: 3 parts, carbon nanotubes: 2.0 parts, amphiphilic nanoscale polymer grafting agent: 2.5 parts, lanthanum benzoate: 0.5 parts, composite antioxidant: 0.5 parts (composed of the main antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and the auxiliary antioxidant tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:2), and hexamethylene diisocyanate trimer: 0.5 parts.

[0112] The preparation method of the reactive core-shell assembly agent includes the following steps: S101. Under nitrogen protection, styrene monomer, crosslinking agent divinylbenzene, and initiator azobisisobutyronitrile were dissolved in toluene at a mass ratio of 100:10:2.0, and a dispersion polymerization reaction was carried out at 85°C for 4 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain crosslinked polystyrene nanospheres with a particle size of approximately 120 nm.

[0113] S102. The obtained cross-linked polystyrene nanospheres are dispersed in an ethanol / water mixed solvent containing polyvinylpyrrolidone (PVP), with the amount of PVP being 15% of the mass of the microspheres. A uniform dispersion is formed under the combined action of stirring and ultrasound.

[0114] S103. Hydroxyethyl methacrylate monomer, styrene monomer, and initiator azobisisobutyronitrile (AIBN) are added sequentially to the dispersion. The mass ratio of hydroxyethyl methacrylate to styrene monomer is 9:1; the mass ratio of the total mass of the two monomers to the mass of the cross-linked polystyrene nanospheres is 2:1; and the amount of AIBN is 2.0% of the total monomer mass. The reaction is carried out at 80℃ for 5 hours. After the reaction is complete, the mixture is centrifuged, washed, and vacuum dried to obtain the reactive core-shell assembly agent.

[0115] The preparation method of porous silica nanospheres loaded with hindered amine light stabilizers includes the following steps: S201. Porous silica nanospheres are impregnated in an acetone solution containing the light stabilizer UV-944, wherein the mass ratio of silica nanospheres to UV-944 is 10:5. The mixture is ultrasonically treated at 60°C for 1 hour, then filtered and dried to obtain a primary powder.

[0116] S202. Under vacuum conditions, the primary powder is heat-treated at 100°C for 2 hours. Then, 5% of the initial mass of the silica nanospheres is added as a silane coupling agent γ-aminopropyltriethoxysilane, and the mixture is reacted at 120°C for 1 hour to obtain porous silica nanospheres loaded with hindered amine light stabilizers.

[0117] The preparation method of the amphiphilic nanoscale polymer grafting agent includes the following steps: S301. Under argon protection, styrene monomer and initiator ethyl α-bromoisobutyrate at a molar ratio of 200:1, along with catalyst cuprous chloride and ligand pentamethyldiethylenetriamine at a molar ratio of 1:1.5, were dissolved in toluene and subjected to atom transfer radical polymerization at 120°C for 4 hours. After the reaction, the mixture was precipitated with methanol, washed, and vacuum dried to obtain a polystyrene macromolecular initiator with bromine atoms at the end.

[0118] S302. The above-mentioned polystyrene macromolecular initiator is redissolved in toluene, and glycidyl methacrylate monomer is added at a molar ratio of 100:1 to the polystyrene macromolecular initiator. Cuprous chloride and PMDETA are added in the same molar amounts as in step S301, and the reaction is continued at 100°C for 6 hours. After the reaction is completed, the mixture is precipitated, washed, and vacuum dried to obtain an amphiphilic nanoscale polymer grafting agent.

[0119] Based on the above-mentioned raw material composition of ABS material, this embodiment also provides a method for preparing ABS material, which includes the following steps: S1. Organic montmorillonite, porous silica nanospheres loaded with hindered amine light stabilizers, carbon nanotubes, and ABS resin powder accounting for 30% of the total mass are dry-mixed in a high-speed mixer for 5 minutes to obtain a nanofiller premix.

[0120] S2. Mix polymethyl methacrylate, amino-terminated polydimethylsiloxane, lanthanum benzoate, composite antioxidant and the remaining 70% ABS resin powder in a high-speed mixer for 5 minutes to obtain matrix functional premix.

[0121] S3. The matrix functional premix, nanofiller premix, reactive core-shell assembling agent, and amphiphilic nanoscale polymer grafting agent are all fed into the main feed hopper of the twin-screw extruder. Hexamethylene diisocyanate trimer is injected into the rear of the melt section via a side-stream liquid injection pump. The temperatures of each section of the twin-screw extruder are controlled as follows: Zone 1: 178℃, Zone 2: 183℃, Zone 3: 188℃, Zone 4: 193℃, Zone 5: 198℃; screw length-to-diameter ratio: 48:1; screw speed: 350 rpm; and vacuum degassing (vacuum degree -0.10 MPa). After melt blending and reaction, the material is extruded, water-cooled, and pelletized to obtain modified ABS granules.

[0122] S4. The obtained modified ABS granules are dried in a forced-air dryer at 85°C for 3 hours to obtain ABS material suitable for injection molding for camera housings.

[0123] Comparative Example 1 This comparative example is modified from the one disclosed in Example 1 as follows: ABS materials do not contain reactive core-shell assemblies in their raw material composition.

[0124] Comparative Example 2 This comparative example is modified from the one disclosed in Example 1 as follows: ABS material does not contain polymethyl methacrylate in its raw material composition.

[0125] Comparative Example 3 This comparative example is modified from the one disclosed in Example 1 as follows: The raw material composition of ABS material does not contain ammonia-terminated polydimethylsiloxane.

[0126] Comparative Example 4 This comparative example is modified from the one disclosed in Example 1 as follows: The raw material composition of ABS material does not contain organic montmorillonite.

[0127] Comparative Example 5 This comparative example is modified from the one disclosed in Example 1 as follows: The raw material composition of ABS material does not contain porous silica nanospheres loaded with hindered amine light stabilizers.

[0128] Comparative Example 6 This comparative example is modified from the one disclosed in Example 1 as follows: The porous silica nanospheres loaded with hindered amine light stabilizers in the raw material composition of ABS materials are replaced with ordinary porous silica nanospheres.

[0129] Comparative Example 7 This comparative example is modified from the one disclosed in Example 1 as follows: ABS material does not contain carbon nanotubes in its raw material composition.

[0130] Comparative Example 8 This comparative example is modified from the one disclosed in Example 1 as follows: The raw material composition of ABS material does not contain amphiphilic nanoscale polymer grafting agents.

[0131] Comparative Example 9 This comparative example is modified from the one disclosed in Example 1 as follows: ABS materials do not contain lanthanum benzoate in their raw material composition.

[0132] Comparative Example 10 This comparative example is modified from the one disclosed in Example 1 as follows: The raw material composition of ABS material does not contain hexamethylene diisocyanate trimer.

[0133] The ABS materials obtained in Examples 1-3 and Comparative Examples 1-10 were subjected to performance tests. The performance test methods are shown in Table 1, and the performance test results are shown in Tables 2 and 3.

[0134] Table 1 Performance Measurement Methods

[0135] Table 2. Properties of ABS materials in Examples 1-3

[0136] Based on the test data of Examples 1 to 3 in Table 2, the ABS material for camera housing prepared in this application exhibits the following properties: In terms of rigidity: the material's flexural strength ranges from 63.2 MPa to 71.0 MPa; its flexural modulus ranges from 2.7 GPa to 3.1 GPa. This indicates that the material has high rigidity and can provide stable mechanical support for precision structural components.

[0137] In terms of toughness: the notched impact strength of the material is between 31.5 kJ / m. 2 ~34.8kJ / m 2 Between. This range indicates that the material maintains high rigidity while possessing excellent impact and crack resistance, achieving a balance between rigidity and toughness.

[0138] Regarding dimensional stability: the material's linear coefficient of thermal expansion is between 46.5 × 10⁻⁶. -6 / K~50.1×10 -6 The coefficient of thermal expansion is between 0.08% and 0.11% in 24 hours. The extremely low coefficient of thermal expansion and water absorption rate together ensure that the material has minimal dimensional changes in environments with varying temperature and humidity, meeting the requirements of high-precision assembly.

[0139] Regarding long-term weather resistance: after 1000 hours of xenon lamp aging, the color difference change ΔE on the material surface ranged from 1.5 to 2.1; the impact strength retention rate ranged from 91.1% to 94.2%. These data indicate that the material has excellent resistance to ultraviolet aging and can maintain the stability of its appearance color and key mechanical properties over a long period of time.

[0140] Table 3. Properties of ABS materials in Comparative Examples 1–10

[0141] Based on the performance data of each comparative example in Table 3, we can conduct an in-depth analysis of the key role of each specific component in the material system.

[0142] Comparative Example 1 (without reactive core-shell assemblies): Performance decreased significantly across the board, with flexural strength (58.2 MPa) and impact strength (22.1 kJ / m²) also declining. 2 Both the dimensional stability (CLTE 90.1) and the structural stability deteriorated. This indicates that this component is the physical reinforcement and reaction core of the system. Its absence causes the material to lose both the load-bearing function of the rigid cross-linked polystyrene core and the interfacial bonding ability of the shell hydroxyl groups to participate in cross-linking, resulting in a significant reduction in the reinforcement network and stress transfer efficiency.

[0143] Comparative Example 2 (without polymethyl methacrylate): The performance of each component changed only slightly compared to Example 1, indicating that PMMA mainly serves as an auxiliary compatibilizer and a supplementary rigid component. Its absence has a limited impact on the main network constructed from the core components, resulting only in a slight decrease in some performance parameters.

[0144] Comparative Example 3 (without amino-terminated polydimethylsiloxane): Impact strength slightly increased (35.1 kJ / m). 2However, the water absorption rate (0.13%) and weather resistance color difference (ΔE 2.2) increased. This reveals that its main function is to participate in cross-linking and migration through amino groups to form a dynamic gradient surface. Its absence slightly weakens the network's water resistance and surface protection, but may unexpectedly increase the impact test value due to changes in interfacial lubricity.

[0145] Comparative Example 4 (without organomodified montmorillonite): The flexural modulus (2.3 GPa) was lower, and the dimensional stability was significantly worse (CLTE 88.0). This directly demonstrates that the two-dimensional physical barrier effect of its nanosheets plays an irreplaceable and crucial role in restricting the thermal motion of molecular chains and reducing the coefficient of thermal expansion.

[0146] Comparative Example 5 (without supported silica nanospheres) and Comparative Example 6 (using ordinary silica nanospheres): The mechanical and dimensional stability data of both were comparable to the examples, but their long-term weather resistance was severely deteriorated (color difference ΔE was as high as 5.2 and 4.8, respectively, and strength retention was only about 81%). This collectively confirms that the "loaded-slow-release" design is the core to achieving long-term weather resistance; physically blended or unloaded light stabilizers cannot provide durable protection.

[0147] Comparative Example 7 (without carbon nanotubes): Impact strength (26.2 kJ / m) 2 A moderate decrease was observed in dimensional stability (CLTE 82.1). This reflects the unique role of one-dimensional carbon nanotubes as "micro-steel bars," which strengthen themselves by bridging and consuming energy during pull-out, and by forming a network to collectively restrict the movement of molecular chains.

[0148] Comparative Example 8 (without amphiphilic nanoscale polymer grafting agent): Performance showed a comprehensive and significant decline, with decreases in flexural modulus (2.1 GPa) and impact strength (22.1 kJ / m²). 2 Both the dimensional stability and dimensional stability (CLTE 85.2) are poor. This undeniably proves the core role of the grafting agent as a "molecular bridge." Its absence leads to the failure of interfacial bonding between the inorganic nanofiller and the organic matrix, filler agglomeration, ineffective stress transfer, and loss of synergistic reinforcement effect.

[0149] Comparative Example 9 (without lanthanum benzoate): The weather resistance color difference (ΔE 3.0) increased, and the strength retention rate (89.2%) decreased. This indicates that lanthanum benzoate, as a UV absorber, constitutes the first line of defense against aging. Its absence allows more UV energy to directly attack the polymer and light stabilizer, accelerating the aging process.

[0150] Comparative Example 10 (without hexamethylene diisocyanate trimer): This is the comparative example with the most severe performance degradation, exhibiting the lowest flexural modulus (2.0 GPa) and a complete collapse in dimensional stability (CLTE as high as 95.3). This definitively proves that the crosslinking agent is the chemical hub for constructing the three-dimensional covalent crosslinked network throughout the entire material system. Without it, other active components cannot be effectively bonded, and the material cannot achieve the structural basis of high rigidity and high dimensional stability.

[0151] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An ABS material for camera housings, characterized in that, The ABS material, by weight, is composed of the following raw materials: ABS resin: 75-85 parts; reactive core-shell assembly agent: 8-12 parts; polymethyl methacrylate: 2-4 parts; amino-terminated polydimethylsiloxane: 1-3 parts; organomodified montmorillonite: 2-4 parts; porous silica nanospheres loaded with hindered amine light stabilizer: 1-3 parts; carbon nanotubes: 0.5-2 parts; amphiphilic nanoscale polymer grafting agent: 1.0-2.5 parts; lanthanum benzoate: 0.3-0.5 parts; composite antioxidant: 0.3-0.5 parts; and hexamethylene diisocyanate trimer: 0.1-0.5 parts. The reactive core-shell assembling agent is a particle with a core-shell structure, wherein the core is cross-linked polystyrene and the shell is a poly(hydroxyethyl methacrylate-co-styrene) copolymer; The amphiphilic nanoscale polymer grafting agent is a linear diblock copolymer containing hydrophobic polystyrene blocks and hydrophilic reactive polymethyl methacrylate blocks.

2. The ABS material for camera housing according to claim 1, characterized in that, The preparation method of the reactive core-shell assembly agent includes the following steps: S101. Under inert gas protection, styrene monomer, crosslinking agent divinylbenzene and initiator azobisisobutyronitrile are dissolved in an organic solvent and dispersed polymerized at 70-85°C for 4-8 hours. After centrifugation, washing and drying, crosslinked polystyrene nanospheres with a particle size of 80-120 nm are obtained. S102. The cross-linked polystyrene nanospheres are dispersed in an alcohol-water mixed solvent containing polyvinylpyrrolidone dispersant, and a uniform dispersion is formed under the combined action of stirring and ultrasound. S103. Hydroxyethyl methacrylate monomer, styrene monomer and initiator azobisisobutyronitrile are added sequentially to the dispersion, and the mixture is reacted at 75-80°C for 5-10 hours to form a poly(hydroxyethyl methacrylate-co-styrene) copolymer shell on the hard core surface through graft copolymerization. After the reaction is completed, the mixture is centrifuged, washed and vacuum dried to obtain the reactive core-shell assembly agent.

3. The ABS material for camera housing according to claim 2, characterized in that, In step S101, the mass ratio of the styrene monomer, the crosslinking agent divinylbenzene, and the initiator azobisisobutyronitrile is 100:(2-10):(0.5-2.0); In step S102, the mass of the polyvinylpyrrolidone dispersant is 5% to 15% of the mass of the cross-linked polystyrene nanospheres; In step S103, the mass ratio of the hydroxyethyl methacrylate monomer to the styrene monomer is (6-9):(1-4); the ratio of the total mass of the hydroxyethyl methacrylate monomer and the styrene monomer to the mass of the cross-linked polystyrene nanospheres is 0.5:1-2:1; and the mass of the initiator azobisisobutyronitrile is 0.5-2.0% of the total mass of the hydroxyethyl methacrylate monomer and the styrene monomer.

4. The ABS material for camera housing according to claim 1, characterized in that, The method for preparing the porous silica nanospheres loaded with hindered amine light stabilizers includes the following steps: S201. Porous silica nanospheres are immersed in an organic solvent solution containing hindered amine light stabilizer and ultrasonically treated at 40-60℃ for 1-3 hours. After solid-liquid separation, a primary powder loaded with hindered amine light stabilizer is obtained. S202 Under vacuum conditions, the primary powder is heat-treated at 80-100°C for 2-4 hours, then a silane coupling agent is added, and the mixture is reacted at 100-120°C for 1-2 hours to obtain the porous silica nanospheres loaded with hindered amine light stabilizers.

5. The ABS material for camera housing according to claim 4, characterized in that, In step S201, the mass ratio of the porous silica nanospheres to the hindered amine light stabilizer is 10:(2-5), and the hindered amine light stabilizer is light stabilizer UV-944; In step S202, the mass of the silane coupling agent is 1 to 5% of the initial mass of the porous silica nanospheres, and the silane coupling agent is γ-aminopropyltriethoxysilane.

6. The ABS material for camera housing according to claim 1, characterized in that, The preparation method of the amphiphilic nanoscale polymer grafting agent includes the following steps: S301. Under inert gas protection, styrene monomer, ethyl α-bromoisobutyrate initiator, and a catalytic system composed of cuprous chloride and N,N,N',N'',N''-pentamethyldiethylenetriamine are dissolved in an organic solvent and subjected to atom transfer radical polymerization at 100-120°C for 4-8 hours. After the reaction, the mixture is precipitated, washed, and vacuum dried to obtain a polystyrene macromolecular initiator with bromine atoms at the end. S302. The polystyrene macromolecular initiator is redissolved in an organic solvent, and glycidyl methacrylate monomer is added. Under the action of the catalytic system, the atom transfer radical polymerization reaction is continued at 80-100°C for 6-12 hours. After the reaction is completed, the mixture is precipitated, washed and vacuum dried to obtain the amphiphilic nanoscale polymer grafting agent.

7. The ABS material for camera housing according to claim 6, characterized in that, In step S301, the molar ratio of the styrene monomer to the initiator ethyl α-bromoisobutyrate is (80-200):1; the molar ratio of the cuprous chloride to the N,N,N',N'',N''-pentamethyldiethylenetriamine is 1:(1-1.5). In step S302, the molar ratio of the glycidyl methacrylate monomer to the polystyrene macromolecular initiator is (30-100):

1.

8. The ABS material for camera housing according to claim 1, characterized in that, The composite antioxidant is composed of a primary antioxidant and a secondary antioxidant. The primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and the secondary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite. The mass ratio of the primary antioxidant to the secondary antioxidant is 1:(1-2).

9. A method for preparing ABS material for camera housing according to any one of claims 1 to 8, characterized in that, The method includes the following steps: S1. Organic montmorillonite, porous silica nanospheres loaded with hindered amine light stabilizer, carbon nanotubes and some ABS resin powder are dry mixed in a high-speed mixer to obtain nanofiller premix. S2. Polymethyl methacrylate, amino-terminated polydimethylsiloxane, lanthanum benzoate, composite antioxidant and the remaining ABS resin powder are mixed in a high-speed mixer to obtain a matrix functional premix. S3. The matrix functional premix, the nanofiller premix, the reactive core-shell assembly agent, and the amphiphilic nanoscale polymer grafting agent are fed into the main feed hopper of a twin-screw extruder. The hexamethylene diisocyanate trimer is injected into the rear part of the melting section through a side-line liquid injection pump. Under the action of screw shearing and vacuum degassing, the mixture is melt-blended and reacted. After extrusion, water cooling, and pelletizing, modified ABS granules are obtained. S4. The modified ABS particles are dried in a forced-air dryer at 75-85°C for 3-5 hours to obtain the ABS material for camera housing that can be used for injection molding.

10. The method for preparing ABS material for camera housing according to claim 9, characterized in that, In step S1, the mass of a portion of the ABS resin powder is 20-30% of the total mass of the ABS resin powder; In step S2, the temperature of each section of the twin-screw extruder is 175-200℃, the screw length-to-diameter ratio is 40:1-48:1, and the screw speed is 200-350 rpm. The vacuum level of the vacuum exhaust is not lower than -0.08 MPa.

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