High-strength high-heat-resistance outdoor household composite material and preparation method thereof

Abstract

The application discloses a kind of high-strength high-heat-resistance outdoor household composite material and preparation method thereof, it is related to polypropylene composite material technical field, including the following components: by mass parts, 100 portions of matrix resin, 10~40 portions of fiber filling, 5~30 portions of inorganic particle, 1~10 portions of auxiliary agent;The matrix resin includes polypropylene and modified polypropylene;Modified polypropylene is obtained by grafting modified polypropylene by rosin acid, fluorine-containing alkyl glycol, 4-chloromethyl styrene modifier.The application is prepared by rosin acid, fluorine-containing alkyl glycol, 4-chloromethyl styrene as raw material, and the modifier with rosin rigid fused ring, low surface energy fluorine-containing segment and high reactivity styrene double bond is obtained, and modified polypropylene is prepared by melting grafting, as the functional component of composite material, can improve its rigidity, impact resistance, heat resistance, surface performance etc.

Description

Technical Field

[0001] This invention relates to the field of polypropylene composite materials technology, specifically a high-strength, high-heat-resistant outdoor home composite material and its preparation method. Background Technology

[0002] With the deepening of urbanization, the scale and number of outdoor public facilities are constantly expanding, placing higher demands on resources, the environment, and economic costs in their construction and maintenance. Traditional steel is widely used due to its high strength and good durability, but it is prone to corrosion and rust during long-term use, leading to a shortened lifespan and increased maintenance frequency. Furthermore, the recycling of waste steel presents problems such as high energy consumption and secondary pollution. Against this backdrop, exploring more sustainable alternative materials has become an urgent priority. Polypropylene, one of the five major general-purpose plastics, has a huge annual consumption. As a thermoplastic general-purpose plastic with excellent comprehensive performance, low cost, and easy processing, it is widely used in the home furnishing industry. However, ordinary polypropylene materials have inherent defects such as insufficient mechanical strength and poor heat resistance, making it difficult to directly meet the stringent requirements of long-term outdoor use. Existing technologies improve these shortcomings by adding fillers, such as fibers or inorganic particles. However, single fiber-reinforced systems often exhibit significant anisotropy, affecting the overall performance and appearance quality of the material; when using particle fillers alone, the reinforcing effect is limited, and high filler content often leads to a decrease in material toughness. Furthermore, as a non-polar polymer, polypropylene exhibits weak interfacial bonding with polar fillers, which exacerbates the degradation of material properties in outdoor environments. Therefore, we propose a high-strength, high-heat-resistant composite material for outdoor home furnishings and its preparation method. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength, high-heat-resistant outdoor home composite material and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-strength and high-heat-resistant outdoor home composite material, comprising: matrix resin, filler and additives.

[0005] Furthermore, the matrix resin is one or more of homopolymer polypropylene, random copolymer polypropylene resin, block copolymer polypropylene, syndiotactic polypropylene, and modified polypropylene.

[0006] Furthermore, the filler includes fiber fillers and inorganic particles; The fiber filler is one or more of carbon fiber, basalt fiber, glass fiber, aramid fiber, and polyester fiber; The inorganic particles are one or more of the following: barium sulfate, calcium carbonate, boron nitride, aluminum oxide, silicon dioxide, titanium dioxide, talc, quartz sand, mica, limestone, and silicates.

[0007] Furthermore, the additives include a mixture of various interface modifiers, compatibilizers, ultraviolet absorbers, light stabilizers, antioxidants, heat stabilizers, and lubricants.

[0008] Furthermore, the composite material comprises the following components: 100 parts by weight of matrix resin, 10 to 40 parts by weight of fiber filler, 5 to 30 parts by weight of inorganic particles, and 1 to 10 parts by weight of additives.

[0009] Furthermore, the fiber filler is preferably carbon fiber or basalt fiber, with a mass ratio of (2-3):(1-2).

[0010] Furthermore, the inorganic particles are preferably boron nitride, aluminum oxide, and mica, with a mass ratio of (3-10):(4-12):(3-8); the boron nitride and mica are in flake form; and the aluminum oxide is in micron and submicron gradations.

[0011] The filler is a blend of fiber fillers and inorganic particles. The fiber fillers include carbon fiber and basalt fiber, both of which possess excellent heat resistance and chemical stability. Basalt fiber also exhibits good UV reflectivity. The inorganic particles are a blend of alumina powder, boron nitride flakes, and mica flakes. Alumina and boron nitride have high thermal conductivity; when incorporated into the composite material, they rapidly conduct heat absorbed on their surface to the entire product and dissipate it into the air, preventing localized heat concentration and reducing peak surface temperature. They also reduce the coefficient of linear expansion and increase the heat distortion temperature. The flake-like mica possesses high-temperature resistance; its scaly structure reflects UV rays and shields against corrosive substances, thereby enhancing the material's high-temperature resistance, UV resistance, and corrosion resistance, making it suitable for outdoor composite materials.

[0012] The combination of fiber fillers and inorganic particles improves the thermal conductivity, heat resistance, UV aging resistance, and environmental corrosion resistance of the resulting composite material, and establishes a reinforcing system. The fiber fillers, acting as a reinforcing phase, overlap in the matrix resin to form a three-dimensional network structure. This network transfers external stress to the fiber fillers through the interface, enabling them to bear most of the external load, thus effectively improving the rigidity, strength, mechanical properties, and heat resistance of the composite material. The inorganic particles fill the gaps in the three-dimensional network structure formed by the fibers, playing a synergistic reinforcing role, optimizing the crystallization and interface of the matrix resin, strengthening the fiber network structure, and further enhancing the overall performance of the composite material. Furthermore, the selection of multi-scale inorganic particles creates a multi-level sized filling structure, achieving dense packing, reducing the free volume within the matrix, and further contributing to the synergistic improvement of the composite material's strength and heat resistance.

[0013] Furthermore, the additives include the following components: compatibilizer, ultraviolet absorber, light stabilizer, antioxidant, heat stabilizer, and lubricant; The compatibilizer is selected from maleic anhydride-grafted polypropylene (PP-g-MAH); the ultraviolet absorber is selected from one or a mixture of two of UV-328 and UV-531; the light stabilizer is selected from hindered amine light stabilizers; the antioxidant is selected from a 1:1 mass ratio of antioxidant 1010 and antioxidant 168; the heat stabilizer is selected from one or a mixture of two of calcium stearate and zinc stearate; the lubricant is selected from one or a mixture of two of polyethylene wax and stearic acid.

[0014] A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings includes the following processes: The matrix resin, filler, and additives are mixed in a high-speed mixer for 5-10 minutes; then melt-blended in a twin-screw extruder and extruded into granules; finally, placed in a mold and hot-pressed by a hot press to obtain a composite material (sheet or profile).

[0015] Furthermore, in the melt blending and extrusion granulation process, the extrusion temperature is: 190-200℃ in zone 1, 200-210℃ in zone 2, 210-215℃ in zone 3, 215-220℃ in zone 4, and the die head temperature is 215-225℃.

[0016] Furthermore, in the hot pressing molding process, the hot pressing temperature is 180-200℃, the hot pressing pressure is 6-10MPa, and the hot pressing time is 8-15 minutes. After hot pressing, the product is held under pressure and cooled to below 60°C before demolding.

[0017] Furthermore, after hot pressing, the material can be annealed at 120-130°C for 1-2 hours to eliminate internal stress, promote secondary crystallization, and improve the mechanical and heat resistance properties of the material.

[0018] Furthermore, the matrix resin comprises 40-80 wt% polypropylene and 20-60 wt% modified polypropylene. Modified polypropylene is obtained by the following process: S1. Preparation of the modifier: A rosin acid, fluorinated alkyl diol, and tervaline anhydride were mixed in tetrahydrofuran, and 4-dimethylaminopyridine was added. The mixture was heated to 60-65°C and reacted for 18-24 hours. The mixture was then rotary evaporated, washed, and the organic phase was separated, dried, and rotary evaporated again to obtain a rosin-based fluorinated alcohol. Rosin-based fluorinated alcohol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor were mixed in toluene and reacted for 36–48 h. After the reaction, deionized water was added, the mixture was separated, the organic phase was neutralized, washed, dried, filtered, and rotary evaporated to obtain the modifier. S2. Modification of polypropylene: Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene.

[0019] Furthermore, the molar ratio of rosin acid, fluorinated alkyl glycol, pentylene anhydride, and 4-dimethylaminopyridine is 1:(1.1-1.2):(1.1-1.2):(0.1-0.2). The fluorinated alkyl glycol is one of perfluorododecanediol (CAS No.: 183162-43-8), perfluorononanediol (CAS No.: 107650-06-6), difluoroheptanediol (CAS No.: 158358-96-4), difluoropropanediol (CAS No.: 428-63-7), and 3-fluoro-1,2-propanediol (CAS No.: 33644-25-6); The amount of tetrahydrofuran used is 5 to 10 times the mass of rosin acid.

[0020] Furthermore, the molar ratio of rosin-based fluorinated alcohol, 4-chloromethylstyrene, potassium carbonate, and polymerization inhibitor (2,6-di-tert-butyl-p-cresol) is 1:(1.2–1.5):(3.0–3.5):(0.01–0.02). The amount of toluene used is 5 to 10 times the mass of rosin-based fluorinated alcohols.

[0021] Furthermore, the modified polypropylene comprises the following components by weight: 100 parts polypropylene, 1 to 5 parts modifier, and 0.1 to 0.3 parts initiator (DCP). Melt grafting is performed using a single-screw extrusion with a processing temperature of 170–180℃ and a die head temperature of 180–190℃.

[0022] Under the action of a dehydrating agent and a catalyst, the carboxyl group in rosin acid reacts with the hydroxyl group in a fluorinated alkyl glycol to form arosin-based fluorinated alcohol. Then, under the action of an alkali, the hydroxyl group in the arosin-based fluorinated alcohol undergoes nucleophilic substitution with 4-chloromethylstyrene, introducing a highly reactive styrene double bond, ultimately yielding a compound with a rigid rosin-based fused ring, a fluorinated alkyl segment, and a styrene double bond, denoted as the modifier. Initiated by a peroxide, the modifier undergoes free radical addition with polypropylene via its styrene double bond, grafting onto the side chain of the polypropylene molecule to obtain modified polypropylene. The rosin group is retained during the grafting process, providing potential reaction sites for subsequent processing and enhancing the compatibility between the modified polypropylene and the co-crosslinking agent.

[0023] The rigid fused ring of rosin is attached to the side chain of polypropylene, restricting the thermal motion of the molecular chain at high temperatures through steric hindrance, promoting stress dispersion, and thus improving the material's rigidity, impact resistance, and heat resistance. The fluorinated alkyl group has high bond energy, increasing the resin's thermal degradation temperature and making it more stable at high temperatures; it is also chemically inert, effectively resisting oxidative degradation at high temperatures, further improving the material's chemical resistance, resistance to thermo-oxidative aging, and weather resistance. The rigid fused ring structure of rosin can capture some UV-generated free radicals, terminating the chain oxidation reaction, giving it a certain UV absorption capacity. It can absorb some UV light energy and dissipate it as heat, thereby improving the composite material's resistance to ultraviolet radiation. Some fluorinated segments migrate to the material surface during processing, forming a low surface energy functional layer that can reflect and scatter UV light, playing a shielding role to some extent, blocking UV light penetration, and simultaneously blocking oxygen permeation, slowing down photo-oxidation reactions. Furthermore, the chemical inertness of the fluorinated segments and the material surface, combined with the hydrophobicity of the rigid fused rings and the reduction of free system by the cross-linked network, hinders the penetration of environmental media into the material content, further improving the material's weather resistance.

[0024] Meanwhile, the polar groups in the modified polypropylene can interact with the surface of the coupling-treated filler, enhancing interfacial bonding, improving system compatibility, and further improving the mechanical strength of the composite material.

[0025] Furthermore, the filler undergoes surface treatment, the specific process of which is as follows: The filler was dried by forced air at 100-110℃ for 4-6 hours to remove surface moisture. Dissolve the silane coupling agent in an aqueous ethanol solution (V 乙醇 ∶V 水 In a mixture of 95:5, the pH of the system was adjusted to 4.5–5.5 using acetic acid to obtain a 1–3 wt% coupling agent solution; The coupling agent solution is sprayed onto the surface of the packing material using a spraying method, and stirred to ensure thorough wetting. The amount of coupling agent solution used is 40-100% of the packing material's mass. The treated filler is then dried and cured at 120–140°C for 15–30 minutes. The silane coupling agent is KH-570 or KH-550.

[0026] Silane coupling agents hydrolyze to generate silanol groups, which react and condense with hydroxyl groups on the filler surface to form a stable coupling layer. This introduces double bonds / amino groups and other organic groups, effectively improving the filler's dispersibility in the matrix resin. The maleic anhydride groups in PP-g-MAH can react with the hydroxyl or amino groups on the filler surface, undergoing chemical cross-linking; while the double bonds can react with free radicals. Simultaneously, hydrogen bonding adsorption exists between the carbonyl groups in PP-g-MAH and the hydroxyl groups in the filler.

[0027] Furthermore, in the melt blending stage, 0.2–0.5 wt% (relative to the mass of the matrix resin) of peroxide initiator (dicumyl peroxide) and 0.5–2.0 wt% of crosslinking agent (styrene, divinylbenzene) are added. The peroxide initiator decomposes at high temperature to generate free radicals. Under the synergistic effect of the crosslinking agent, micro-crosslinking of polypropylene, modified polypropylene, and surface double bond functionalized fillers is initiated, forming an interfacial crosslinking structure with C-C covalent bonds, thereby improving the heat resistance and mechanical properties of the prepared composite material.

[0028] Through multiple interfacial interactions, including chemical crosslinking, physical entanglement, and hydrogen bonding, the resulting composite material exhibits high strength. The crosslinked network and interfacial covalent bonds effectively transfer stress to the filler through the interfacial layer, thereby fully leveraging the load-bearing capacity of the reinforcing phase. The crosslinked network restricts the thermal motion of molecular chains, synergistically improving the heat distortion temperature and long-term thermal stability of the composite material in conjunction with the high-temperature resistance of the filler. Simultaneously, the relatively dense crosslinked structure reduces the penetration of oxygen and ultraviolet radiation into the material, working synergistically with added weather-resistant additives to delay the aging process of the composite material.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention constructs a multi-level reinforcement system for composite materials by combining fiber fillers and inorganic particles. The fiber fillers, as the main reinforcing phase, form a three-dimensional network structure in the matrix resin, effectively improving the rigidity, strength, mechanical properties, heat resistance, and UV weather resistance of the composite material. The inorganic particles fill the gaps in the fiber network, exerting a synergistic reinforcing effect with the fibers, further enhancing the overall performance of the composite material. The fillers undergo surface treatment with a silane coupling agent to achieve organic functionalization modification, effectively improving the dispersibility and interfacial compatibility of the fillers in the matrix resin, laying the foundation for subsequent interfacial crosslinking.

[0030] 2. This invention uses rosin acid, fluorinated alkyl glycol, and 4-chloromethylstyrene as raw materials to prepare a modifier that combines the rigid fused rings of rosin, low surface energy fluorinated segments, and highly reactive styrene double bonds. Modified polypropylene is then obtained by melt grafting. As a functional component of composite materials, it can improve the rigidity, impact resistance, heat resistance, UV resistance, surface properties, etc.

[0031] 3. This invention introduces peroxide initiators and crosslinking aids during the melt blending stage, enabling polypropylene, modified polypropylene, and surface double bond functionalized fillers to participate in micro-crosslinking. This constructs a three-dimensional chemical network with C-C covalent bonds within the matrix and at the interface, allowing the material to achieve superior heat resistance and mechanical durability while maintaining good processing fluidity. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the following specific embodiments, unless otherwise specified, all parts refer to parts by weight; it should be noted that the raw materials involved in this invention are not subject to any special limitations, and include, for example: Polypropylene is isotactic polypropylene T30S; carbon fiber: chopped UTS50; basalt fiber: average length 6mm, aspect ratio 470; boron nitride: flakes, layer thickness ≤0.1μm, average particle size 10-12μm; alumina is a blend of 65wt% micron-sized and 35wt% submicron-sized alumina, with an average particle size of 10μm for micron-sized alumina and 0.8μm for submicron-sized alumina; mica: flakes, average particle size 50μm; the thickness of the sheet is 15mm. The compatibilizer is maleic anhydride-grafted polypropylene (PP-g-MAH, CMG9801); the ultraviolet absorbers are UV-328 and UV-531, with a mass ratio of 2:1; the light stabilizer is Tinuvin 770; the antioxidants are antioxidant 1010 and antioxidant 168, with a mass ratio of 1:1; the heat stabilizer is calcium stearate; the lubricant is polyethylene wax; the polymerization inhibitor is 2,6-di-tert-butyl-p-cresol; the initiator is dicumyl peroxide (DCP); in the ethanol-water solution, the volume ratio of ethanol to water is 95:5. The surface treatment process of the filler is as follows: the filler is dried in a forced-air dryer at 105℃ for 5 hours to remove surface moisture; the silane coupling agent is dissolved in an ethanol aqueous solution, and the pH of the system is adjusted to 5.0 using acetic acid to obtain a 2wt% coupling agent solution; the coupling agent solution is sprayed onto the surface of the filler using a spray method, and stirred to fully wet it, with the amount of coupling agent solution being 70% of the filler mass; then the treated filler is dried and cured at 130℃ for 20 minutes.

[0034] Example 1: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Preparation of modified polypropylene: Abrasive acid, fluorinated alkyl glycol, and tervaline anhydride were mixed in tetrahydrofuran, and 4-dimethylaminopyridine was added. The mixture was heated to 60°C and reacted for 24 hours. The mixture was then rotary evaporated, washed, and the organic phase was separated, dried, and rotary evaporated again to obtain arosin-based fluorinated alcohol. The molar ratio of abrasive acid, fluorinated alkyl glycol, tervaline anhydride, and 4-dimethylaminopyridine was 1:1.1:1.1:0.1. The fluorinated alkyl glycol was difluoroheptanediol. The amount of tetrahydrofuran used was 8 times the mass of abrasive acid. Rosin-based fluorinated alcohol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor were mixed in toluene and reacted for 36 hours. After the reaction, deionized water was added, the mixture was separated, the organic phase was neutralized, washed, dried, filtered, and rotary evaporated to obtain the modifier. The molar ratio of rosin-based fluorinated alcohol, 4-chloromethylstyrene, potassium carbonate, and polymerization inhibitor was 1:1.2:3.0:0.01. The amount of toluene used was 8 times the mass of the rosin-based fluorinated alcohol. Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene. The modified polypropylene includes the following components by mass: 100 parts polypropylene, 1 part modifier, and 0.1 parts initiator. The melt grafting is carried out by single-screw extrusion at a processing temperature of 170°C and a die head temperature of 180°C. S2. Surface treatment of filler: The specific process is described above, and the silane coupling agent is KH-570; The filler consists of fiber filler and inorganic particles. The fiber filler is carbon fiber and basalt fiber (mass ratio of 2:1), and the inorganic particles are boron nitride, alumina, and mica (mass ratio of 5:6:4). S3. Molding of composite materials: A composite of 80 wt% polypropylene and 20 wt% modified polypropylene was used as the matrix resin. 100 parts of the matrix resin, 10 parts of fiber filler, 30 parts of inorganic particles, and 5 parts of additives (2.5 parts compatibilizer, 0.5 parts UV absorber, 0.5 parts light stabilizer, 0.3 parts antioxidant, 0.2 parts heat stabilizer, and 1.0 part lubricant) were mixed in a high-speed mixer for 5 minutes. The mixture is melt-blended in a twin-screw extruder and then extruded and granulated. The extrusion temperatures are: 190℃ in zone 1, 200℃ in zone 2, 210℃ in zone 3, 215℃ in zone 4, and 215℃ at the die head. During the melt-blending process, 0.2 wt% of dicumyl peroxide and 0.5 wt% of styrene as a crosslinking agent are added. Then it is placed in a mold and hot-pressed by a hot press. The hot pressing temperature is 180℃, the hot pressing pressure is 6MPa, and the hot pressing time is 15 minutes. After hot pressing, it is held under pressure and cooled to 40℃ before demolding. Then it is annealed at 120℃ for 2 hours to obtain the sheet material, which is the composite material.

[0035] Example 2: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Preparation of modified polypropylene: Abrasive acid, fluorinated alkyl glycol, and tervaline anhydride were mixed in tetrahydrofuran, and 4-dimethylaminopyridine was added. The mixture was heated to 62°C and reacted for 21 h. The mixture was then rotary evaporated, washed, and the organic phase was separated, dried, and rotary evaporated again to obtain arosin-based fluorinated alcohol. The molar ratio of abrasive acid, fluorinated alkyl glycol, tervaline anhydride, and 4-dimethylaminopyridine was 1:1.15:1.15:0.15. The fluorinated alkyl glycol was perfluorononanediol. The amount of tetrahydrofuran used was 8 times the mass of abrasive acid. Rosin-based fluorinated alcohol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor were mixed in toluene and reacted for 42 hours. After the reaction, deionized water was added, the mixture was separated, the organic phase was neutralized, washed, dried, filtered, and rotary evaporated to obtain the modifier. The molar ratio of rosin-based fluorinated alcohol, 4-chloromethylstyrene, potassium carbonate, and polymerization inhibitor was 1:1.3:3.2:0.01. The amount of toluene used was 8 times the mass of the rosin-based fluorinated alcohol. Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene. The modified polypropylene includes the following components by mass: 100 parts polypropylene, 3 parts modifier, and 0.3 parts initiator. The melt grafting is carried out by single-screw extrusion at a processing temperature of 175°C and a die head temperature of 185°C. S2. Surface treatment of filler: The specific process is described above, and the silane coupling agent is KH-550; The filler consists of fiber filler and inorganic particles. The fiber filler is carbon fiber and basalt fiber (mass ratio 5:3), and the inorganic particles are boron nitride, alumina, and mica (mass ratio 6:8:5). S3. Molding of composite materials: A composite of 60 wt% polypropylene and 40 wt% modified polypropylene was used as the matrix resin. 100 parts of the matrix resin, 25 parts of fiber filler, 17 parts of inorganic particles, and 5 parts of additives (2.5 parts compatibilizer, 0.5 parts UV absorber, 0.5 parts light stabilizer, 0.3 parts antioxidant, 0.2 parts heat stabilizer, and 1.0 part lubricant) were mixed in a high-speed mixer for 8 minutes. The mixture is melt-blended in a twin-screw extruder and then extruded and granulated. The extrusion temperatures are: 195℃ in zone 1, 205℃ in zone 2, 212℃ in zone 3, 217℃ in zone 4, and 220℃ at the die head. During the melt-blending process, 0.3wt% of dicumyl peroxide and 1.2wt% of divinylbenzene, a co-crosslinking agent, are added. The material is then placed in a mold and hot-pressed using a hot press. The hot pressing temperature is 190℃, the hot pressing pressure is 8MPa, and the hot pressing time is 12 minutes. After hot pressing, the material is held under pressure and cooled to 40℃ before demolding. Then, it is annealed at 125℃ for 1.5 hours to obtain the sheet material, which is the composite material.

[0036] Example 3: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Preparation of modified polypropylene: Abrasive acid, fluorinated alkyl glycol, and tervaline anhydride were mixed in tetrahydrofuran, and 4-dimethylaminopyridine was added. The mixture was heated to 65°C and reacted for 18 hours. The mixture was then rotary evaporated, washed, and the organic phase was separated, dried, and rotary evaporated again to obtain arosin-based fluorinated alcohol. The molar ratio of abrasive acid, fluorinated alkyl glycol, tervaline anhydride, and 4-dimethylaminopyridine was 1:1.1:1.1:0.1. The fluorinated alkyl glycol was perfluorododecanediol. The amount of tetrahydrofuran used was 8 times the mass of abrasive acid. Rosin-based fluorinated alcohol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor were mixed in toluene and reacted for 48 hours. After the reaction, deionized water was added, the mixture was separated, the organic phase was neutralized, washed, dried, filtered, and rotary evaporated to obtain the modifier. The molar ratio of rosin-based fluorinated alcohol, 4-chloromethylstyrene, potassium carbonate, and polymerization inhibitor was 1:1.5:3.5:0.02. The amount of toluene used was 8 times the mass of the rosin-based fluorinated alcohol. Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene. The modified polypropylene includes the following components by mass: 100 parts polypropylene, 5 parts modifier, and 0.3 parts initiator. The melt grafting is carried out by single-screw extrusion at a processing temperature of 180°C and a die head temperature of 190°C. S2. Surface treatment of filler: The specific process is described above, and the silane coupling agent is KH-570; The filler consists of fiber filler and inorganic particles. The fiber filler is carbon fiber and basalt fiber (mass ratio 3:2), and the inorganic particles are boron nitride, alumina, and mica (mass ratio 3:4:3). The filler was dried in a forced-air dryer at 105℃ for 5 hours to remove surface moisture; the silane coupling agent was dissolved in an aqueous ethanol solution, and the pH of the system was adjusted to 5.0 using acetic acid to obtain a 3wt% coupling agent solution. The coupling agent solution was sprayed onto the surface of the filler using a spray method, and stirred to ensure thorough wetting. The amount of coupling agent solution used was 100% of the filler mass. The treated filler was then dried and cured at 130℃ for 30 minutes. The silane coupling agent used was KH-570. S3. Molding of composite materials: A composite of 40 wt% polypropylene and 60 wt% modified polypropylene was used as the matrix resin. 100 parts of the matrix resin, 40 parts of fiber filler, 5 parts of inorganic particles, and 5 parts of additives (2.5 parts compatibilizer, 0.5 parts UV absorber, 0.5 parts light stabilizer, 0.3 parts antioxidant, 0.2 parts heat stabilizer, and 1.0 part lubricant) were mixed in a high-speed mixer for 10 minutes. The mixture is melt-blended in a twin-screw extruder and then extruded and granulated. The extrusion temperatures are: 200℃ in zone 1, 210℃ in zone 2, 215℃ in zone 3, 220℃ in zone 4, and 225℃ at the die head. During the melt-blending process, 0.5 wt% of dicumyl peroxide and 2.0 wt% of divinylbenzene, a co-crosslinking agent, are added. Then it is placed in a mold and hot-pressed by a hot press. The hot pressing temperature is 200℃, the hot pressing pressure is 10MPa, and the hot pressing time is 8 minutes. After hot pressing, it is held under pressure and cooled to 40℃ before demolding. Then it is annealed at 130℃ for 1 hour to obtain the sheet material, which is the composite material.

[0037] Comparative Example 1: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Preparation of modified polypropylene: Abrasive acid, 1,7-heptadecyl glycol, and tervapotranhydride were mixed in tetrahydrofuran, and 4-dimethylaminopyridine was added. The mixture was heated to 60°C and reacted for 24 hours. The mixture was then rotary evaporated, washed, and the organic phase was separated, dried, and rotary evaporated again to obtain abrasive alcohol. The molar ratio of abrasive acid, 1,7-heptadecyl glycol, tervapotranhydride, and 4-dimethylaminopyridine was 1:1.1:1.1:0.1. The amount of tetrahydrofuran used was 8 times the mass of abrasive acid. Rosin alcohol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor were mixed in toluene and reacted for 36 hours. After the reaction, deionized water was added, the mixture was separated, the organic phase was neutralized, washed, dried, filtered, and rotary evaporated to obtain the modifier. The molar ratio of rosin alcohol, 4-chloromethylstyrene, potassium carbonate, and polymerization inhibitor was 1:1.2:3.0:0.01. The amount of toluene used was 8 times the mass of rosin alcohol. Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene. The modified polypropylene includes the following components by mass: 100 parts polypropylene, 1 part modifier, and 0.1 parts initiator. The melt grafting is carried out by single-screw extrusion at a processing temperature of 170°C and a die head temperature of 180°C. S2-3 is the same as in Example 1, resulting in a composite material.

[0038] Comparative Example 2: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Preparation of modified polypropylene: Dodecylfluoroheptanol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor were mixed in toluene and reacted for 36 hours. After the reaction, deionized water was added, the mixture was separated, the organic phase was neutralized, washed, dried, filtered, and rotary evaporated to obtain the modifier. The molar ratio of dodecylfluoroheptanol, 4-chloromethylstyrene, potassium carbonate, and polymerization inhibitor was 1:1.2:3.0:0.01. The amount of toluene used was 8 times the mass of dodecylfluoroheptanol. Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene. The modified polypropylene includes the following components by mass: 100 parts polypropylene, 1 part modifier, and 0.1 parts initiator. The melt grafting is carried out by single-screw extrusion at a processing temperature of 170°C and a die head temperature of 180°C. S2-3 is the same as in Example 1, resulting in a composite material.

[0039] Comparative Example 3: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Preparation of modified polypropylene: Polypropylene, styrene, and an initiator are mixed and melt-grafted to obtain modified polypropylene. The modified polypropylene comprises the following components by mass: 100 parts polypropylene, 1 part styrene, and 0.1 parts initiator. The melt grafting is performed using a single-screw extrusion with a processing temperature of 170°C and a die head temperature of 180°C. S2-3 is the same as in Example 1, resulting in a composite material.

[0040] Comparative Example 4: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Surface treatment of the filler: Same as S2 in Example 1; S2. Molding of composite materials: 100 parts of matrix resin polypropylene, 10 parts of fiber filler, 30 parts of inorganic particles and 5 parts of additives were mixed in a high-speed mixer for 5 minutes; other processes were the same as S3 in Example 1 to obtain the composite material.

[0041] Comparative Example 5: A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, comprising the following processes: S1. Surface treatment of the filler: Same as S2 in Example 1; S2. Molding of composite materials: 100 parts of matrix resin polypropylene, 40 parts of inorganic particles and 5 parts of additives were mixed in a high-speed mixer for 5 minutes; other processes were the same as S3 in Example 1 to obtain the composite material.

[0042] Experiment: The composite materials obtained in Examples 1-3 and Comparative Examples 1-5 were used to prepare samples. Their properties were tested and the test results were recorded. The samples were equilibrated for 24 hours at 23±2℃ and 50±5%RH. Mechanical property testing: Tensile tests were conducted using a universal testing machine with a tensile rate of 10 mm / min, in accordance with GB / T 1040.2; Notched impact performance tests were conducted using a cantilever pendulum impact tester, in accordance with GB / T 1843; The notch was a V-notch. Heat resistance test: The sample was placed in a heat treatment at 120℃ for 24 hours. The dimensional changes of the sample before and after the test were detected. The maximum value of the change rate in the length direction and the width direction was taken as the dimensional stability index. Referring to GB / T 7141, the sample was suspended in a forced ventilation oven at 150℃ and aged for 168 hours. The tensile strength of the sample before and after the test was detected, and the strength retention rate was calculated. Corrosion resistance test: According to GB / T 11547, the sample was immersed in 10wt.% HCl solution for 720h (30 days), and the tensile strength retention rate of the sample was detected after the test. UV aging resistance test: Referring to GB / T 14522, the sample was placed under a UVA-340 lamp and irradiated for 1000 hours (8 hours of irradiation followed by 4 hours of condensation). After the test, the tensile strength retention rate and gloss retention rate of the sample were measured.

[0043] Based on the data in the table above, the following conclusions can be clearly drawn: The composite materials obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-5. The test results show that... The composite materials obtained in Examples 1-3 exhibit higher tensile strength, impact strength, and lower dimensional change rate, with higher strength retention data after thermo-oxidative aging, UV aging, and acid immersion. This fully demonstrates that the present invention improves the strength and heat resistance of the prepared composite materials, and enhances their resistance to thermo-oxidative aging and surface properties.

[0044] Compared to Example 1, the modifier in Comparative Example 1 was prepared differently, containing no fluorine; the modifier in Comparative Example 2 did not contain a rosin-based structure; the modifier in Comparative Example 3 was replaced with styrene; the matrix resin in Comparative Example 4 was polypropylene, and no peroxide initiator or crosslinking agent was added during melt blending; based on Comparative Example 4, the filler in Comparative Example 5 was inorganic particles. The tensile strength, impact strength, strength retention, and dimensional change rate of the composite materials in Comparative Examples 1-5 deteriorated. It can be seen that the formulation and process settings of the composite materials in this invention help improve strength, heat resistance, resistance to thermo-oxidative aging, and surface properties.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A high-strength, high-heat-resistant composite material for outdoor home furnishings, characterized in that: It comprises the following components by weight: 100 parts matrix resin, 10-40 parts fiber filler, 5-30 parts inorganic particles, and 1-10 parts additives; wherein the matrix resin includes polypropylene and modified polypropylene. The modified polypropylene is obtained by grafting polypropylene with a modifier made from rosin acid, fluorinated alkyl glycol, and 4-chloromethylstyrene.

2. The high-strength, high-heat-resistant composite material for outdoor home furnishings according to claim 1, characterized in that: The fiber filler includes carbon fiber and basalt fiber, with a mass ratio of (2-3):(1-2); The inorganic particles include boron nitride, aluminum oxide, and mica, in a mass ratio of (3-10):(4-12):(3-8).

3. A method for preparing a high-strength, high-heat-resistant composite material for outdoor home furnishings, characterized in that: Including the following processes: The matrix resin, filler, and additives are mixed in a high-speed mixer; then melt-blended in a twin-screw extruder, extruded and granulated; and finally placed in a mold and hot-pressed to obtain a composite material.

4. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 3, characterized in that: The matrix resin comprises 40-80 wt% polypropylene and 20-60 wt% modified polypropylene. Modified polypropylene is obtained by the following process: A rosin acid, fluorinated alkyl glycol, and tervaline anhydride are mixed in tetrahydrofuran, and 4-dimethylaminopyridine is added. The mixture is heated to 60–65 °C and reacted for 18–24 h to obtain a rosin-based fluorinated alcohol. A rosin-based fluorinated alcohol, potassium carbonate, 4-chloromethylstyrene, and a polymerization inhibitor are mixed in toluene and reacted for 36–48 h to obtain a modifier. Polypropylene, modifier, and initiator are mixed and melt-grafted to obtain modified polypropylene.

5. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 4, characterized in that: The molar ratio of rosin acid to fluorinated alkyl diol is 1: (1.1 to 1.2). The fluorinated alkyl glycol is one of perfluorododecanediol, perfluorononanediol, difluoroheptanediol, difluoropropanediol, and 3-fluoro-1,2-propanediol; The molar ratio of rosin-based fluoroalcohol and 4-chloromethylstyrene is 1: (1.2 to 1.5).

6. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 4, characterized in that: The modified polypropylene comprises the following components by weight: 100 parts polypropylene, 1 to 5 parts modifier, and 0.1 to 0.3 parts initiator; Melt grafting is performed using a single-screw extrusion with a processing temperature of 170–180℃ and a die head temperature of 180–190℃.

7. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 3, characterized in that: In the melt blending stage, 0.2-0.5% of dicumyl peroxide and 0.5-2.0% of a crosslinking agent by weight of the matrix resin are added. The crosslinking agent is one or both of styrene and divinylbenzene.

8. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 3, characterized in that: The filler is surface-treated with a silane coupling agent, which is KH-570 or KH-550.

9. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 3, characterized in that: In the melt blending and extrusion granulation process, the extrusion temperature is: Zone 1 190-200℃, Zone 2 200-210℃, Zone 3 210-215℃, Zone 4 215-220℃, and the die head temperature is 215-225℃.

10. The method for preparing a high-strength, high-heat-resistant outdoor furniture composite material according to claim 3, characterized in that: In the hot pressing molding process, the hot pressing temperature is 180-200℃, the hot pressing pressure is 6-10MPa, and the hot pressing time is 8-15min. After hot pressing, it is annealed at 120-130℃ for 1-2 hours.

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