High-performance, high-weather-resistance and good-appearance nylon composite material and preparation method thereof

Abstract

The invention discloses a nylon composite material with high performance, high weather resistance and good appearance and a preparation method thereof, and belongs to the technical field of polymer composite materials. A functional metal organic framework layer is constructed on the surface of glass fiber, Zr < 4 + > ions and a 2, 5-bis (2-carboxyphenyl)-1, 3, 4-oxadiazole ligand form a three-dimensional network structure, Ce ions are doped, and a slow-release benzotriazole corrosion inhibitor is loaded. The composite material is prepared from 20 to 60 parts of PA6, 15 to 45 parts of modified glass fiber, 1 to 5 parts of titanium dioxide, 0.3 to 1 part of a light stabilizer, 0.3 to 1 part of a pH regulator, 0.3 to 1 part of a coupling agent, 0.2 to 0.9 part of an antioxidant and 0.3 to 1 part of a lubricant. The color difference of the material is only 0.8 after a xenon lamp is aged for 500 hours, the tensile strength retention rate reaches 85%, the tensile strength retention rate reaches 82% after the material is subjected to damp-heat aging for 1000 hours, and the phenomenon of floating fibers on the appearance is eliminated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer composites, and particularly relates to a high-performance, high-weather-resistance, and good-look nylon composite material and a preparation method thereof. BACKGROUND

[0002] Polyamide, commonly known as nylon, is widely used in garden tools, mechanical equipment and other fields due to its excellent mechanical strength, wear resistance, chemical corrosion resistance and self-lubricity. However, the amide bond in the molecular structure of ordinary polyamide material is sensitive to ultraviolet light and oxygen, and when used outdoors for a long time, it is prone to problems such as strength reduction, color yellowing, surface powdering, cracking and the like, i.e. poor weather resistance, which greatly limits its application in outdoor parts.

[0003] In the prior art, the weather resistance of polyamide is usually improved by adding ultraviolet shielding agents or ultraviolet absorbers, light stabilizers and the like. Ultraviolet shielding agents such as titanium dioxide can reflect and scatter ultraviolet light to achieve the first protection, ultraviolet absorbers can absorb a certain amount of ultraviolet light to achieve the second protection, and light stabilizers can eliminate free radicals to protect the deep layer of the material to achieve the third protection. However, titanium dioxide has high hardness and is easy to be ground into glass fibers during production, greatly reducing the rigidity and toughness. The single use of ultraviolet absorbers or light stabilizers sometimes cannot meet the requirements of product color or high whiteness. CN108752543A discloses a weather-resistant glass fiber reinforced nylon composite material which improves the ultraviolet protection ability of the material by combining silicon dioxide coated titanium dioxide and hindered amine light stabilizers, but still has obvious technical limitations. The patent fails to effectively solve the fundamental contradiction between the addition of titanium dioxide and the maintenance of mechanical properties. The addition of titanium dioxide leads to a significant decrease in impact strength, indicating that the interface design has defects and cannot maintain the toughness of the material while enhancing the weather resistance. More importantly, this technical solution only focuses on the single protection mechanism of ultraviolet shielding, lacks effective measures to respond to the acidic environment caused by nylon hydrolysis in a humid and hot environment, resulting in rapid performance degradation of the material in a humid and hot environment.

[0004] In addition, when encountering a humid and hot environment outdoors, the acidic environment caused by the chain scission and hydrolysis of nylon will continuously reduce the anti-ultraviolet effect of the light stabilizer. For example, the nylon composite material containing a benzotriazole ultraviolet absorber proposed in CN109575387A improves the initial weather resistance of the material to some extent by optimizing the ratio of ultraviolet absorber and hindered amine light stabilizer, but still shows obvious performance deficiencies in long-term outdoor use. The biggest defect of this patent is that it fails to solve the problem of deactivation of light stabilizers caused by acidic substances generated by nylon hydrolysis in a humid and hot environment, lacks effective pH regulation mechanism, and causes the weather resistance of the material to decrease rapidly in a humid and hot environment, which is the main reason for the obvious color change after long-term use.

[0005] Therefore, it has important industrial application value to develop a new material which can maintain excellent mechanical properties of polyamide and significantly improve its weather resistance such as ultraviolet resistance, heat and humidity resistance, high and low temperature impact resistance and the like after adding titanium white. SUMMARY

[0006] One of the purposes of the present application is to provide a high-performance, high-weather-resistance and good-appearance nylon composite material to solve the problems of poor weather resistance of nylon material, decreased mechanical properties after adding titanium white and performance attenuation in a humid heat environment and the like in the prior art.

[0007] The second purpose of the present application is to provide a preparation method of a high-performance, high-weather-resistance and good-appearance nylon composite material for preparing the high-performance, high-weather-resistance and good-appearance nylon composite material.

[0008] The purposes of the present application can be achieved by the following technical solutions. In a first aspect, a high-performance, high-weather-resistance and good-appearance nylon composite material is composed of the following components by weight: PA6 20-60 parts, Modified glass fiber 15-45 parts, Titanium white 1-5 parts, Light stabilizer 0.3-1 part, pH regulator 0.3-1 part, Coupling agent 0.3-1 part, Antioxidant 0.2-0.9 parts, Lubricant 0.3-1 part. The modified glass fiber is glass fiber coated with a functionalized metal organic framework layer, the metal organic framework layer is formed by coordination bond between Zr 4+ Ions and 2,5-bis(2-carboxyphenyl)-1,3,4-oxadiazole ligands form a three-dimensional network structure, wherein Ce 3+ Ions are doped, and a slow-release benzotriazole corrosion inhibitor is loaded by physical adsorption.

[0009] The PA6 formulation range of 20-60 parts ensures sufficient molecular chain length and crystallinity in the nylon matrix, while providing a suitable dispersion environment for other additives, achieving an optimal balance between mechanical and processing properties. The modified glass fiber formulation of 15-45 parts ensures uniform dispersion of the glass fiber in the matrix, forming an effective reinforcing network while maintaining good processing fluidity. The titanium dioxide addition of 1-5 parts is the optimal range determined through extensive experimentation; less than 1 part is insufficient to provide effective UV shielding, resulting in poor material weather resistance; more than 5 parts leads to excessive rigidity, a significant decrease in toughness, and the high hardness of titanium dioxide makes it easy to abrade the glass fiber during production, causing deterioration of mechanical properties. The light stabilizer formulation of 0.3-1 part ensures sufficient UV protection, forming a synergistic protection system with the photocatalytic effect of the MOF structure, achieving comprehensive protection at both the surface and deep layers. The pH adjuster, at a ratio of 0.3-1 parts, is designed to maintain the acid-base balance of the system under humid and hot conditions. The slow-release properties of disodium dihydrogen pyrophosphate and the corrosion inhibitor loaded in MOF form a double buffer mechanism, stabilizing the system pH within the ideal range of 6.2-6.5. The coupling agent, at a dosage range of 0.3-1 parts, ensures optimized interfacial bonding. The titanate coupling agent synergistically interacts with the carboxyl groups in the MOF structure to construct a three-level interfacial network of "titanium dioxide-MOF-nylon," significantly enhancing interfacial bonding and improving interfacial shear strength. The composite system of antioxidants (TFB 117, 1098, S-9228), at 0.2-0.9 parts, provides comprehensive antioxidant protection. Synergistically, it works with the near-infrared reflection effect of the MOF structure to improve antioxidant efficiency, especially under conditions where the material surface temperature decreases by 8-10°C, significantly inhibiting the thermo-oxidative aging process. The lubricant formulation of 0.3-1 parts balances processing performance and interfacial bonding. The zinc ions in zinc stearate coordinate with the MOF structure, enhancing interfacial stability and eliminating fiber floating.

[0010] The functionalized metal-organic framework layer on the modified glass fiber surface is made of Zr 4+ The ions form with a 2,5-bis(2-carboxyphenyl)-1,3,4-oxadiazole ligand. This specific ligand design has a dual function: the carboxyl group ensures stable coordination with the Zr cluster, while the oxadiazole ring provides excellent UV absorption and free radical scavenging capabilities. Compared to conventional ligands, this innovative design improves free radical scavenging efficiency, and the rigid planar structure facilitates the formation of stable porous structures. Ce-doped Ce in the MOF layer... 3+ Ions and Zr 4+ The formation of a Zr-O-Ce heterojunction generates a near-infrared reflection effect, reducing the material surface temperature by 8-10°C compared to traditional materials; simultaneously, Ce... 3+ The d orbital of the oxadiazole ligand π The track forms a charge transfer system, which significantly improves the efficiency of free radical capture. The slow-release benzotriazole corrosion inhibitor loaded by physical adsorption releases on demand in the MOF channel under a humid heat environment, neutralizing the acidity of the system. Compared with the traditional direct addition of corrosion inhibitor, this slow-release mechanism stabilizes the pH value of the system at 6.2-6.5 during the humid heat aging process, avoids the deactivation of the light stabilizer, and maintains a high level of tensile strength retention after 1000 hours of humid heat aging.

[0011] Further, the modified glass fiber is prepared by the following steps: A1, surface treatment of an alkali-free glass fiber in an oxygen plasma to introduce carboxyl groups; A2, immersing the glass fiber treated in step A1 into an N,N-dimethylformamide solution containing a zirconium salt, a carboxyl-containing organic ligand and a cerium salt to react, thereby forming a metal organic framework layer on the surface of the fiber; A3, immersing the product obtained in step A2 into an ethanol solution containing benzotriazole to load the corrosion inhibitor.

[0012] Further, in step A1, the oxygen plasma treatment time is 5-10 minutes.

[0013] Oxygen plasma treatment for 5-10 minutes introduces an appropriate amount of carboxyl groups on the surface of the glass fiber, providing nucleation sites for MOF growth. If the treatment time is too short, it is not enough to form enough carboxyl groups, affecting the uniformity of the MOF layer; if the treatment time is too long, it will cause excessive etching of the fiber surface, reducing the strength of the fiber. This time range ensures that the surface carboxyl group density is moderate, promoting uniform growth of the MOF and maintaining the mechanical integrity of the fiber.

[0014] Further, in step A2, the zirconium salt is ZrCl4, the carboxyl-containing organic ligand is 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole, and the cerium salt is Ce(NO3)3.

[0015] Further, in step A2, in the N,N-dimethylformamide solution, the concentration of ZrCl4 is 0.05-0.2 mol / L, the concentration of 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole is 0.05-0.2 mol / L, and the concentration of Ce(NO3)3 is 0.001-0.003 mol / L.

[0016] The concentration ratio of ZrCl4, 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole and Ce(NO3)3 in step A2 is optimized to ensure the uniform and dense growth of the MOF layer. Imbalance of the concentration ratio will result in low crystallinity or incomplete structure of the MOF, affecting the function. The MOF layer formed under this ratio achieves the best balance between function and interface combination.

[0017] Further, in step A2, the reaction is carried out at 120℃ for 6-8 hours.

[0018] The condition of reaction at 120℃ for 6-8 hours ensures sufficient crystallization and stable growth of MOF layer. The MOF layer formed under this condition has high crystallinity and ideal thickness, and the free radical capture efficiency reaches the peak.

[0019] Further, in step A3, the concentration of the benzotriazole ethanol solution is 0.04-0.06 mol / L.

[0020] Further, in step A3, the adsorption process is carried out at 60℃ for 4-6 hours.

[0021] The benzotriazole ethanol solution concentration of 0.04-0.06 mol / L and the adsorption process at 60℃ for 4-6 hours ensure appropriate loading and uniform distribution of corrosion inhibitor in the MOF channel. Too low concentration or too short time leads to insufficient loading; too high or too long may lead to channel supersaturation, affecting the slow-release effect.

[0022] Further, the relative viscosity of the PA6 resin is 2.5-3.4 Pa·S.

[0023] The PA6 resin relative viscosity of 2.5-3.4 Pa·S corresponds to a suitable molecular weight range, ensuring that the material has good mechanical properties and processing performance.

[0024] Further, the titanium white is rutile titanium white.

[0025] The choice of rutile titanium white is based on its higher refractive index, better UV shielding ability and lower photocatalytic activity. Compared with anatase, rutile provides more excellent UV reflection and scattering effect, significantly improving the weather resistance of the material.

[0026] Further, the light stabilizer includes at least one of ultraviolet absorber Tinuvin 1600, light stabilizer Chimassorb 944, and light stabilizer HALS 622.

[0027] The combination of light stabilizers forms a synergistic protection system: Tinuvin 1600 absorbs ultraviolet light, Chimassorb 944 and HALS 622 capture free radicals. The synergistic effect of the three improves the tensile strength retention rate after xenon lamp aging, improves compared with a single protection system, and realizes comprehensive protection of the surface and deep layer.

[0028] Further, the pH regulator is disodium hydrogen pyrophosphate.

[0029] Dipotassium hydrogen pyrophosphate as pH regulator provides slow-release characteristics and does not cause sharp changes in pH value. Effectively protects the activity of light stabilizer and improves the tensile strength retention rate after hydrothermal aging.

[0030] Further, the coupling agent is a titanate coupling agent.

[0031] Compared with traditional silane coupling agents, the titanate coupling agent has low moisture sensitivity and can simultaneously form bonds with various inorganic fillers to construct a more complex interface network. It significantly improves the interface bonding force and the problem of floating fibers in appearance.

[0032] Further, the antioxidant is at least one of Clariant TFB 117, antioxidant 1098, and antioxidant S-9228.

[0033] The antioxidant composite system (TFB 117, 1098, S-9228) provides comprehensive antioxidant protection, 1098 captures free radicals, S-9228 decomposes peroxides, and TFB 117 provides comprehensive protection. The synergistic effect of the three and the thermal management effect of the MOF structure cooperate to reduce the performance degradation rate of the material in complex outdoor environments and improve the tensile strength retention rate after xenon lamp aging.

[0034] Further, the lubricant is at least one of zinc stearate, TAF, and OP wax.

[0035] The lubricant combination (zinc stearate, TAF, and OP wax) achieves multiple functions: improving melt flowability, reducing floating fibers in appearance, and improving surface quality.

[0036] In a second aspect, a preparation method of a high-performance, high-weather-resistant, and good-appearance nylon composite material includes the following steps: S1. Mixing the dried PA6 with titanium dioxide, light stabilizer, pH regulator, coupling agent, antioxidant, and lubricant in a predetermined ratio to obtain a mixture; S2. Adding the mixture from the main feeding port into a double-screw extruder and adding modified glass fiber from the side feeding port into the double-screw extruder, and then performing melt extrusion and granulation to obtain a high-performance, high-weather-resistant, and good-appearance nylon composite material.

[0037] In the preparation method, the process design of adding the base mixture from the main feeding port and adding the modified glass fiber from the side feeding port protects the surface structure of the MOF modified glass fiber. If the glass fiber and the base are simultaneously added from the main feeding port, the MOF layer will be damaged under high-temperature shear, increasing the color difference (△E) after xenon lamp aging and thus reducing the tensile strength retention rate.

[0038] Further, the extrusion temperature of the double-screw extruder is 220-255°C.

[0039] The temperature range of 220-255℃ of the twin-screw extruder ensures smooth melting and uniform mixing of the material, while avoiding thermal degradation. The temperature gradient design (180-255℃) allows the material to undergo gradual melting, protecting the MOF structural integrity. Too low a temperature results in uneven mixing and obvious floating fibers; too high a temperature causes thermal degradation of PA6, resulting in a decrease in mechanical properties.

[0040] Advantages of the present application: (1) The present application uses 20-60 parts of PA6 as the base resin, combined with 1-5 parts of rutile titanium dioxide as an ultraviolet shielding agent, which not only significantly improves the solid color and whiteness of the product, but also effectively reflects and scatters ultraviolet light, forming a first heavy protective barrier to greatly block the damage of ultraviolet light to the material surface layer. At the same time, by adding 0.3-1 parts of a light stabilizer, a second protective barrier is formed to absorb ultraviolet light and eliminate free radicals; and the addition of 0.3-1 parts of a pH adjuster effectively maintains the acid value of the system within a stable range, avoiding the acidic environment caused by the hydrolysis of nylon chain scission in a humid and hot environment, thereby ensuring the long-term effectiveness of the light stabilization system. In particular, the use of 0.3-1 parts of a titanate coupling agent not only significantly improves the uniformity of the dispersion of titanium dioxide in the nylon matrix, but also enhances the interfacial bonding force between titanium dioxide and the nylon matrix, combined with 0.2-0.9 parts of an antioxidant and 0.3-1 parts of a lubricant, which plays a key protective role in the entire life cycle of the material: effectively solving the problem of mechanical property degradation caused by the addition of titanium dioxide in traditional technology, while improving the appearance of floating fibers in the product.

[0041] (2) The present application uses modified glass fiber (15-45 parts), which has a photocatalytic-slow-release dual functional metal organic framework structure on the surface of the glass fiber. This structure not only actively captures and catalytically decomposes free radicals generated by ultraviolet light, but also forms a dynamic hydrogen bond network with the nylon matrix through carboxyl groups, significantly enhancing the interfacial bonding force. In particular, the doping of Ce 3+ ions endows the material with near-infrared reflective ability, reducing heat accumulation under sunlight; the loaded corrosion inhibitor releases on demand in a humid and hot environment, neutralizing the acidity of the system and protecting the activity of the light stabilizer. This multi-mechanism synergistic effect achieves simultaneous inhibition of the "light-heat-humidity" triple aging factors, reducing the performance degradation rate of the material in complex outdoor environments.

[0042] (3) The present application constructs a functional metal organic framework layer on the surface of the glass fiber, achieving simultaneous inhibition of the "light-heat-humidity" triple aging factors, specifically: the rigid planar structure of the 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole ligand and the Ce 3+The d orbitals form a charge transfer system, enhancing free radical capture efficiency. The controlled release of benzotriazole through MOF channels stabilizes the pH of the system under humid and hot conditions, avoiding the deactivation of light stabilizers caused by increased acid value in traditional materials. The near-infrared reflection effect generated by the Zr-O-Ce heterojunction reduces the surface temperature of the material, significantly inhibiting thermo-oxidative aging. This material possesses advantages such as high performance, high weather resistance, and good appearance, making it significant for the development and application of nylon materials in garden tools, household appliances, and other fields. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0044] The reagents used in this embodiment and their suppliers are as follows: The PA6 resin used is YH800 produced by Hunan Yuehua Chemical Co., Ltd., with a relative viscosity of 2.8 Pa·s. The glass fiber is 568H chopped PA fiber produced by China Jushi Co., Ltd., which has excellent hydrolysis resistance. The titanium dioxide is DuPont titanium dioxide R105 from the United States; The ultraviolet absorber Tinuvin 1600 and the light stabilizer Chimassorb 944 are manufactured by BASF. Sodium dihydrogen pyrophosphate is produced by Hubei Xinrunde Chemical Co., Ltd. The titanate coupling agent LICA38 is manufactured by Condis Chemicals Ltd. Antioxidant TFB 117 is sourced from Clariant. Antioxidant 1098 is manufactured by BASF; Antioxidant S-9228 is manufactured by Dover Chemicals; Zinc stearate is sourced from Anhui Shafeng New Materials Co., Ltd.

[0045] The reagents described above are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to provide full disclosure, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0046] Example 1

[0047] This embodiment provides a high-performance, highly weather-resistant, and aesthetically pleasing nylon composite material, prepared through the following steps: (a) Preparation of functionalized glass fibers: PA chopped fiber 568H produced by China Jushi Co., Ltd. was treated in oxygen plasma for 8 minutes; the treated glass fiber was then immersed in a solution of 0.1 mol / L ZrC. , 0.1 mol / L 2,5-bis(2-carboxyphenyl)-1,3,4-oxadiazole and 0.002 mol / L Ce(N The product was immersed in 0.05 mol / L benzotriazole ethanol solution at 60°C for 4 hours to obtain functionalized glass fiber; (b) 64.7 parts by weight of nylon 6, 2 parts by weight of titanium white, 0.5 parts by weight of sodium dihydrogen pyrophosphate, 0.5 parts by weight of titanate, 0.4 parts by weight of TFB 117, 0.2 parts by weight of antioxidant 1098, 0.2 parts by weight of antioxidant S-9228, 0.4 parts by weight of Tinuvin 1600, 0.4 parts by weight of Chimassorb 944, 0.4 parts by weight of HALS 622 and 0.3 parts by weight of lubricant zinc stearate were pre-mixed in a high-speed mixer for 10 min, then added to a twin-screw extruder at the main discharge port, and then 30 parts of the functionalized glass fiber prepared in step (a) was added to the side feeding port of the twin-screw extruder, and the rotation speed of the twin-screw extruder was controlled at 300 rpm, and the extrusion temperature of each zone was controlled at 180°C in the first zone, 250°C in the second zone, 240°C in the third zone, 230°C in the fourth zone, 230°C in the fifth zone, 225°C in the sixth zone, 225°C in the seventh zone, 230°C in the eighth zone, 235°C in the ninth zone, 245°C in the tenth zone, and 255°C in the die head. After melting extrusion and granulation, a high-performance, high-weather-resistant, and good-appearance nylon composite material was obtained.

[0048] Example 2

[0049] The difference between this example and Example 1 is that 0.001 mol / L Ce(NO3)3 is used in the MOF precursor solution.

[0050] The remaining raw materials and preparation process remain the same as in Example 1.

[0051] Example 3

[0052] The difference between this example and Example 1 is that 0.003 mol / L Ce(NO3)3 is used in the MOF precursor solution.

[0053] The remaining raw materials and preparation process remain the same as in Example 1.

[0054] Example 4

[0055] The difference between this example and Example 1 is that the concentration of benzotriazole in step (a) is adjusted to 0.03 mol / L.

[0056] The remaining raw materials and preparation process remain the same as in Example 1.

[0057] Example 5

[0058] The difference between this embodiment and embodiment 1 is that the MOF ligand is replaced by traditional 1,4-benzenedicarboxylic acid (BDC).

[0059] The remaining raw materials and preparation process remain the same as in embodiment 1.

[0060] Example 6

[0061] The difference between this embodiment and embodiment 1 is that the amount of disodium hydrogen pyrophosphate is adjusted to 0.3 parts by weight.

[0062] The remaining raw materials and preparation process remain the same as in embodiment 1.

[0063] Example 7

[0064] The difference between this embodiment and embodiment 1 is that the titanate coupling agent is replaced by silane coupling agent KH-550.

[0065] The remaining raw materials and preparation process remain the same as in embodiment 1.

[0066] Example 8

[0067] The difference between this embodiment and embodiment 1 is that the amount of titanium dioxide is adjusted to 1 part by weight.

[0068] The remaining raw materials and preparation process remain the same as in embodiment 1.

[0069] Comparative Example 1

[0070] A method for preparing a high-performance, high-weather-resistance, and good- appearance nylon composite material, comprising the following steps: After 64.7 parts by weight of nylon 6, 2 parts by weight of titanium dioxide, 0.5 parts by weight of disodium hydrogen pyrophosphate, 0.5 parts by weight of titanate, 0.4 parts by weight of TFB 117, 0.2 parts by weight of antioxidant 1098, 0.2 parts by weight of antioxidant S-9228, 0.4 parts by weight of Tinuvin 1600, 0.4 parts by weight of Chimassorb 944, 0.4 parts by weight of HALS 622, and 0.3 parts by weight of lubricant zinc stearate are pre-mixed in a high-speed mixer for 10 minutes, they are added to a twin-screw extruder at the main discharge port, and then 30 parts of ordinary glass fiber without MOF treatment is added to the twin-screw extruder at the side feeding port. The rotation speed of the twin-screw extruder is controlled at 300 rpm, and the extrusion temperature of each zone is controlled at 180°C in the first zone, 250°C in the second zone, 240°C in the third zone, 230°C in the fourth zone, 230°C in the fifth zone, 225°C in the sixth zone, 225°C in the seventh zone, 230°C in the eighth zone, 235°C in the ninth zone, 245°C in the tenth zone, and 255°C at the die head. After melting extrusion and granulation, a high-performance, high-weather-resistance, and good-appearance nylon composite material is obtained.

[0071] Comparative Example 2

[0072] This comparative example is compared with Example 1, the difference being that no Ce(NO3)3 is added in the MOF precursor solution.

[0073] The remaining raw materials and preparation process remain the same as Example 1.

[0074] Comparative Example 3

[0075] This comparative example is compared with Example 1, the difference being that the corrosion inhibitor loading step in step (a) is omitted.

[0076] The remaining raw materials and preparation process remain the same as Example 1.

[0077] Comparative Example 4

[0078] This comparative example is compared with Example 1, the difference being that the MOF ligand is replaced by the traditional 1,4-benzenedicarboxylic acid (BDC).

[0079] The remaining raw materials and preparation process remain the same as Example 1.

[0080] Comparative Example 5

[0081] This comparative example is compared with Example 1, the difference being that the glass fibers are treated with a conventional silane coupling agent, and no MOF structure is used.

[0082] The remaining raw materials and preparation process remain the same as Example 1.

[0083] Performance Test

[0084] The performance test is carried out on the examples and comparative examples, and the specific items and test standards are as follows: 1. Mechanical property test: Tensile strength: GB / T 1040.2-2022 (ISO 527); Elongation at break: GB / T 1040.2-2022 (ISO 527); Bending strength: GB / T 9341-2008 (ISO 178); Bending modulus: GB / T 9341-2008 (ISO 178); Charpy notched impact strength: GB / T 1043.1-2008 (ISO 179); 2. Weather resistance test: Xenon lamp aging: GB / T 16422.2-2022 (ISO 4892-2), test conditions: irradiance 0.55 W / m 2@340 nm, black panel temperature 63℃, humidity 65%, light / spraying cycle 120 min / 18 min, total time 500 h; Hygrothermal aging: GB / T 3681-2011, test condition: 85℃ / 85%RH, 1000 h; Color difference (△E): GB / T 39822-2021, using spectrophotometer to measure the color change of the sample before and after aging; 3. Appearance of floating fibers: Visual evaluation: no floating fibers, slight floating fibers, obvious floating fibers, severe floating fibers; The results are shown in Table 1: Table 1

[0085] As can be seen from Table 1, by constructing a functional metal organic framework (MOF) layer on the surface of the glass fiber, the present application realizes the simultaneous inhibition of the "light-heat-humidity" triple aging factors, solves the key technical problems such as poor weather resistance of traditional nylon composite materials, mechanical property decline after adding titanium dioxide, and performance decay in a humid heat environment, etc. The test data show that the color difference (△E) of Example 1 after xenon lamp aging for 500 hours is only 0.8, the tensile strength retention rate reaches 85%, the tensile strength retention rate reaches 82% after hygrothermal aging for 1000 hours, and the appearance effect of "no floating fibers" is achieved, and all the performances are significantly better than those of all the comparative examples. In particular, the charge transfer system formed by 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole ligand and Ce 3+ The free radical capture efficiency is improved, the controlled release of the corrosion inhibitor by the MOF channel maintains the pH value of the system in the ideal range of 6.2-6.5, the near-infrared reflection effect of the Zr-O-Ce heterojunction reduces the surface temperature of the material by 8-10℃, and the triple mechanism synergistically reduces the performance decay rate of the material in the complex outdoor environment.

[0086] In addition, the present application breaks through the contradiction between "titanium dioxide addition and mechanical property maintenance", and the impact strength (14.8 KJ / m 2 ) of Example 1 not only does not decrease due to the addition of titanium dioxide, but also is 3.5% higher than that of Comparative Example 1, and the weather resistance is greatly improved. The creativity of the present application lies in the discovery of the synergistic mechanism between the MOF structure, titanium dioxide and the pH adjuster: the carboxyl group in the MOF structure forms a Zr-O-Ti bridge with the hydroxyl group on the surface of the titanium dioxide, and a "titanium dioxide-MOF-nylon" three-level interface network is constructed; the Ce 3+The doping not only improves the near-infrared reflection ability of the MOF, but also enhances the free radical capture efficiency through an electron transfer mechanism; the controlled release of the corrosion inhibitor and the pH regulator form a double buffering mechanism, effectively maintaining the stability of the system pH. These synergistic effects enable the material to maintain high strength (172 MPa) while achieving excellent weather resistance and perfect appearance quality.

[0087] The performance of Example 5 (using a traditional MOF ligand) and Example 7 (using a silane coupling agent) decreases significantly, proving the irreplaceability of the specific MOF structure design of the present application. Although Comparative Examples 2-5 use some innovative elements, they lack the unique synergistic mechanism of the present application, so the performance improvement is limited. The present application not only solves the long-standing technical bottleneck in the industry, but also opens up a new direction for the technical development of high-performance nylon composite materials, and has important value for the development of nylon materials in outdoor application fields such as electric tools, garden equipment, and household appliances.

[0088] The above disclosure is only a few specific embodiments of the present application, but the embodiments of the present application are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the scope of the present application.

Claims

1. A high performance, high weatherability, good appearance nylon composite, characterized in that, Composed of the following components by weight: PA6 20-60 parts, Modified glass fiber 15-45 parts, Titanium dioxide 1-5 parts, Light stabilizer 0.3-1 part, pH regulator 0.3-1 part, Coupling agent 0.3-1 part, Antioxidant 0.2-0.9 parts, Lubricant 0.3-1 part; The modified glass fiber is a glass fiber coated with a functionalized metal organic framework layer, the metal organic framework layer is made of Zr 4+ Ions and 2,5-bis(2-carboxyphenyl)-1,3,4-oxadiazole ligands form a three-dimensional network structure through coordination bonds, wherein Ce 3+ Ions are doped, and a slow-release benzotriazole corrosion inhibitor is loaded through physical adsorption.

2. The high performance, high weatherability, good appearance nylon composite material according to claim 1, characterized in that, The modified glass fiber is prepared by the following steps: A1, the surface of the alkali-free glass fiber is treated in oxygen plasma to introduce carboxyl groups; A2, the glass fiber treated in step A1 is immersed in a N,N-dimethylformamide solution containing zirconium salt, carboxyl-containing organic ligand and cerium salt to react, thereby forming a metal organic framework layer on the surface of the fiber; A3, the product obtained in step A2 is immersed in an ethanol solution containing benzotriazole to load corrosion inhibitor.

3. The high performance, high weatherability, good appearance nylon composite material according to claim 2, characterized in that, In step A1, the oxygen plasma treatment time is 5-10 minutes.

4. The high performance, high weatherable, good appearance nylon composite material according to claim 2, characterized in that, In step A2, the zirconium salt is ZrCl4, the carboxyl-containing organic ligand is 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole, and the cerium salt is Ce(NO3)3; In the N,N-dimethylformamide solution, the concentration of ZrCl4 is 0.05-0.2 mol / L, the concentration of 2,5-di(2-carboxyphenyl)-1,3,4-oxadiazole is 0.05-0.2 mol / L, and the concentration of Ce(NO3)3 is 0.001-0.003 mol / L; The reaction is carried out at 120℃ for 6-8 hours.

5. The high performance, high weatherable, good appearance nylon composite material according to claim 2, characterized in that, In step A3, the concentration of the benzotriazole ethanol solution is 0.04-0.06 mol / L; The adsorption process is carried out at 60℃ for 4-6 hours.

6. The high performance, high weatherable, good appearance nylon composite material according to claim 1, characterized in that, The relative viscosity of the PA6 resin is 2.5-3.4 Pa·S.

7. The high performance, high weatherable, good appearance nylon composite material according to claim 1, characterized in that, The titanium dioxide is rutile titanium dioxide; The light stabilizer includes at least one of ultraviolet absorber Tinuvin 1600, light stabilizer Chimassorb 944, and light stabilizer HALS 622; The pH regulator is disodium hydrogen pyrophosphate; The coupling agent is a titanate coupling agent.

8. The high performance, high weatherable, good appearance nylon composite material according to claim 1, characterized in that, The antioxidant is at least one of Clariant TFB 117, antioxidant 1098, and antioxidant S-9228; The lubricant is at least one of zinc stearate, TAF, and OP wax.

9. A method for preparing high performance, high weatherability, good appearance nylon composite material, characterized in that, A method for preparing the high-performance, high-weather-resistance, and good-appearance nylon composite material of any one of claims 1-8, comprising the following steps: S1, mixing the dried PA6 with titanium dioxide, light stabilizer, pH regulator, coupling agent, antioxidant, and lubricant according to the proportion to obtain a mixture; S2, adding the mixture from the main feeding port into the double-screw extruder, and adding the modified glass fiber from the side feeding port into the double-screw extruder, and then carrying out melt extrusion and granulation to obtain a high-performance, high-weather-resistance, and good-appearance nylon composite material.

10. The method for preparing a high-performance, high-weather-resistant, and good-appearance nylon composite material according to claim 9, characterized in that, The extrusion temperature of the double-screw extruder is 220-255℃.

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