Continuous long glass fiber reinforced high-temperature nylon material and preparation method thereof

Abstract

The invention discloses a continuous long glass fiber reinforced high-temperature nylon material and a preparation method thereof, and the material comprises the following components by mass: 50%-70% of matrix resin, 30%-50% of continuous alkali-free long glass fiber (E-Glass), 0.2%-1% of a coupling agent based on the mass of the continuous alkali-free long glass fiber, 0.2%-0.5% of an antioxidant system, 0.2%-0.8% of a lubricant, and 0-0.5% of other auxiliary agents. The technical problems that an existing high-temperature nylon reinforced material is weak in interface bonding, insufficient in impregnation, single in performance and the like are effectively solved, and remarkable comprehensive advantages are achieved. According to the formula, the continuous alkali-free long glass fiber is used as a core reinforcement and matched with the KH-550 coupling agent to construct a firm interface, and the interface shear strength is improved by 50% compared with that of a traditional short glass fiber material; nano particles and PPS rigid chains are introduced for synergistic modification, so that the bending modulus reaches up to 19.5 GPa, the thermal deformation temperature breaks through 280 DEG C, and synergistic upgrading of rigidity and high temperature resistance is achieved.

Description

Technical Field

[0001] This invention relates to the field of high-temperature nylon materials, and more specifically, to a continuous long glass fiber reinforced high-temperature nylon material and its preparation method. Background Technology

[0002] As the automotive industry moves towards lightweight and high reliability, and electronic and electrical equipment upgrades towards miniaturization and high-temperature resistance, the aerospace field faces increasingly stringent requirements for the comprehensive performance of structural materials. High-temperature nylon, due to its excellent high-temperature resistance, chemical corrosion resistance, and dimensional stability, has become one of the core engineering plastics replacing metal components. However, the mechanical strength, rigidity, and heat deformation resistance of pure high-temperature nylon still fall short of the demands of high-end applications, such as automotive engine peripheral components and heat dissipation structures for electronic devices. Therefore, fiber reinforcement technology is needed to improve its overall performance.

[0003] Currently, high-temperature nylon reinforcement modification mainly employs two technical approaches: short glass fiber reinforcement and continuous long glass fiber reinforcement. While short glass fiber reinforced materials offer good processing flowability and lower cost, the fibers are prone to breakage during processing, resulting in shorter lengths (typically less than 1 mm) and limited load transfer efficiency. This leads to only a limited improvement in impact resistance and fatigue resistance, and the materials experience rapid performance degradation under long-term high-temperature use. Continuous long glass fiber reinforced thermoplastics (LFTs), with their fiber length consistent with the granules (6-12 mm) and direct and efficient load transfer, significantly outperform short glass fiber reinforced materials in terms of strength, rigidity, and fatigue resistance, making them the preferred solution for high-end applications.

[0004] However, existing continuous long glass fiber reinforced high-temperature nylon materials and their preparation processes still have many technical problems:

[0005] 1. Poor interfacial compatibility: The high-temperature nylon matrix and glass fiber have significantly different surface polarities, resulting in weak interfacial adhesion and a tendency for "debonding" to occur. This leads to insufficient mechanical properties of the composite material, especially low interlaminar shear strength.

[0006] 2. Poor impregnation quality: High-temperature nylon melt has high viscosity and a narrow processing window (usually only 20-30℃). Traditional impregnation dies are unable to form a uniform high-pressure field, resulting in insufficient fiber bundle unfolding and the appearance of "dry yarn" (fibers not impregnated by resin), which seriously affects the reinforcement effect.

[0007] 3. Insufficient stability in processing and use: High-temperature nylon has a high moisture absorption rate. If it is not dried thoroughly before processing, it is easy to cause bubbles and silver streaks in the product. In addition, the resin is prone to thermal oxidative aging during high-temperature processing, which affects the service life of the material. At the same time, when the glass fiber content is high (40%-50%), the impact toughness of the material decreases significantly, and it causes serious wear to the processing equipment.

[0008] 4. Limited Functionality: Existing reinforcement systems mostly focus on improving mechanical properties, lacking design for synergistic optimization of lubricity and rigidity, making it difficult to meet the low friction requirements during component assembly and the high rigidity requirements of complex structures. Summary of the Invention

[0009] The purpose of this invention is to provide a continuous long glass fiber reinforced high-temperature nylon material and its preparation method, so as to solve the technical problems existing in the background art.

[0010] The present invention provides a continuous long glass fiber reinforced high-temperature nylon material, comprising the following components by mass percentage: 50%-70% matrix resin, 30%-50% continuous alkali-free long glass fiber (E-Glass), 0.2%-1% coupling agent based on the mass of the continuous alkali-free long glass fiber, 0.2%-0.5% antioxidant system, 0.2%-0.8% lubricant, and 0-0.5% other additives; wherein the matrix resin is high-temperature nylon, and the high-temperature nylon is selected from at least one of polyphthalamide (PPA), PA6T, PA9T, and PA10T with a long-term service temperature ≥150℃.

[0011] In a preferred embodiment, the continuous alkali-free long glass fiber has a single filament diameter of 10-17 μm and a fiber bundle linear density of 2400-4800 tex.

[0012] In a preferred embodiment, the coupling agent is selected from aminosilane coupling agents, which can form chemically bonded molecular bridges between a high-temperature nylon matrix and continuous alkali-free long glass fibers.

[0013] In a preferred embodiment, the aminosilane coupling agent is KH-550.

[0014] In a preferred embodiment, the antioxidant system is a compound system of primary antioxidant and secondary antioxidant, wherein the primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168, and the mass ratio of the primary antioxidant to the secondary antioxidant is (1:1)-(2:1).

[0015] In a preferred embodiment, the lubricant is selected from at least one of calcium stearate, silicone powder, polyethylene wax (PE wax), and pentaerythritol stearate, which can improve the processing fluidity of resin melts and reduce equipment wear.

[0016] In a preferred embodiment, the material further includes a synergistic modifying component, which is composed of nanoparticles and PPS rigid chains. The nanoparticles are selected from at least one of SiO2 and ZrC. The total mass percentage of the synergistic modifying component is 1%-5%. The nanoparticles and PPS rigid chains work synergistically to improve the rigidity, lubricity, and high-temperature stability of the material.

[0017] A method for preparing a continuous long glass fiber reinforced high-temperature nylon material includes the following steps:

[0018] S1, Raw material pretreatment: Place the high-temperature nylon resin in a 120℃ forced-air drying oven or dehumidifying dryer and dry for 4-6 hours to reduce the resin moisture content to below 0.02% (200ppm);

[0019] S2, Fiber Guiding and Spreading: The continuous alkali-free long glass fiber yarn is kept under constant tension by a tension control system, and then spread and thinned by multiple sets of roller-type spreading devices with adapted angles, so that the fiber bundle is loose and uniform.

[0020] S3, Resin Melting and Metering: The dried high-temperature nylon resin, antioxidant system, lubricant, and other additives are added to a special impregnation screw extruder through a precision metering feeder. The heating temperature is set according to the melting point and melt index of the high-temperature nylon resin to melt and plasticize the resin. The processing temperature is controlled at 290℃-315℃.

[0021] S4, Melt Impregnation: Molten resin is delivered to a customized impregnation die head, and simultaneously merged into the die head with the unfolded glass fiber bundle. The high-pressure melt inside the die head penetrates and tightly wraps each glass fiber monofilament.

[0022] S5, Cooling and Pelletizing: The impregnated fiber / resin composite material is extruded from the die head and immediately sent to a cooling water tank for rapid cooling and solidification. Then, it is pulled at a constant speed by a traction roller and finally cut into 6-12 mm pellets by a pelletizer.

[0023] The customized impregnation die head described in S4 has a narrow flow channel and several spaced baffles inside. These baffles create a high-pressure gradient in the molten resin, forcing the melt to penetrate into the fiber bundle. S4 precisely controls the processing temperature, die head pressure, and fiber tension, ensuring the glass fiber bundle is completely impregnated by the molten resin, with no exposed white dry fibers visible to the naked eye, thus guaranteeing a strong interfacial bond between the fiber and the resin.

[0024] The beneficial effects of the technical solution of this invention are:

[0025] This invention effectively solves the technical pain points of existing high-temperature nylon reinforced materials, such as weak interfacial adhesion, insufficient impregnation, and limited performance, and possesses significant comprehensive advantages. In terms of formulation, it uses continuous alkali-free long glass fibers as the core reinforcement, combined with KH-550 coupling agent to construct a robust interface, increasing the interfacial shear strength by 50% compared to traditional short glass fiber materials. The introduction of nanoparticles and PPS rigid chains for synergistic modification results in a flexural modulus reaching up to 19.5 GPa and a heat distortion temperature exceeding 280℃, achieving a synergistic upgrade in rigidity and high-temperature resistance.

[0026] In terms of process, the customized impregnation die head and gradient yarn spreading design ensure complete fiber impregnation. Combined with precise drying and temperature control, it avoids defects such as bubbles and dry yarn in the finished product, and reduces equipment wear by 30%. The product has a balanced overall performance, with a maximum tensile strength of 310MPa. Its impact toughness is still superior to existing technologies even with high glass fiber content. It meets the high strength and high rigidity requirements of high-end scenarios such as automotive, electronics, and aerospace, while also having good processing fluidity. It broadens the application boundaries of high-temperature nylon materials and combines technological innovation with practical application value. Detailed Implementation

[0027] The present invention will now be described in further detail. The embodiments of the invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0028] All raw materials used in this solution are commercially available standard products: high-temperature nylon (PPA, melting point 305℃, melt index 15g / 10min), PA6T (melting point 310℃, melt index 12g / 10min); continuous alkali-free long glass fiber (E-Glass, monofilament diameter 13μm, fiber bundle linear density 3600tex); coupling agent KH-550; antioxidants 1010 and 168; lubricants (calcium stearate, silicone powder); nano-SiO2 (particle size 50nm), nano-ZrC (particle size 80nm); PPS rigid chains (melting point 280℃, number average molecular weight 1.2×10⁻⁶). 5 ).

[0029] Example 1 (Basic formulation, without synergistic modifying components)

[0030] 1. Formulation composition (percentage by mass)

[0031] Matrix resin: PPA 60%; Continuous alkali-free long glass fiber: 39%; Coupling agent (KH-550): 0.5% (based on the weight of glass fiber, i.e., 0.195% of total mass); Antioxidant system: Antioxidant 1010 0.2% + Antioxidant 168 0.1% (mass ratio 2:1); Lubricant: Silicone powder 0.2%; Other additives: None (0%).

[0032] 2. Preparation steps

[0033] S1, Raw material pretreatment: PPA resin was dried in a 120℃ dehumidifying dryer for 5 hours, and the moisture content was found to be 0.015% (150ppm).

[0034] S2, Fiber Guiding and Spreading: The continuous alkali-free long glass fiber yarn is kept under a constant tension of 5N by a tension control system. The fiber bundle is spread to 2.5 times its original width by three sets of roller-type spreading devices with angles of 30°, 60° and 90° respectively, ensuring that the fiber is loose and uniform.

[0035] S3, Resin Melting and Metering: The dried PPA resin, antioxidant system, and silicone powder are added to a special impregnation screw extruder through a precision metering feeder. The heating temperature is set in zones: Zone 1 290℃, Zone 2 300℃, Zone 3 310℃, Zone 4 305℃, Zone 5 300℃, Zone 6 300℃, and the die head 310℃, so that the resin is fully melted and plasticized.

[0036] S4, Melt Impregnation: Molten resin is delivered to a customized impregnation die head (with 3 narrow slit channels and 4 baffles spaced 15mm apart). The die head pressure is controlled at 12MPa and the fiber tension is maintained at 5N, so that the high-pressure melt can forcefully penetrate the fiber bundle and tightly wrap each monofilament. No white dry yarn can be observed with the naked eye.

[0037] S5, Cooling and pelletizing: After the impregnated composite material is extruded, it is immediately sent to a 25°C cooling water tank for 30 seconds. It is then pulled by a traction roller at a constant speed of 1.5 m / min and finally cut into 8 mm pellets by a synchronous pelletizer.

[0038] Example 2 (containing synergistic modification components, SiO2+PPS rigid chains)

[0039] 1. Formulation composition (percentage by mass)

[0040] Matrix resin: PA6T 55%; Continuous alkali-free long glass fiber: 40%; Coupling agent (KH-550): 0.8% (based on glass fiber mass, i.e., 0.32% of total mass); Antioxidant system: Antioxidant 1010 0.15% + Antioxidant 168 0.15% (mass ratio 1:1); Lubricant: Calcium stearate 0.3%; Synergistic modifier: Nano SiO2 2% + PPS rigid chain 2% (total 4%); Other additives: None (0%).

[0041] 2. Preparation steps

[0042] S1, Raw material pretreatment: PA6T resin and PPS rigid chain were mixed and dried in a 120℃ forced-air drying oven for 6 hours. The moisture content was found to be 0.012% (120ppm).

[0043] S2, Fiber Guiding and Yarn Spreading: The tension of the glass fiber yarn is controlled at 6N, and it is spread to 3 times its original width through 4 sets of roller-type yarn spreading devices with angles of 20°, 45°, 75° and 100°.

[0044] S3, Resin Melting and Metering: Add the mixed and dried PA6T, PPS rigid chain, antioxidant system, calcium stearate, and nano SiO2 to the impregnated screw extruder. Zone heating temperatures: Zone 1 290℃, Zone 2 305℃, Zone 3 315℃, Zone 4 310℃, Zone 5 305℃, Zone 6 305℃, and Die head 315℃.

[0045] S4, Melt impregnation: Die head pressure is controlled at 14MPa, fiber tension is 6N, and other parameters are the same as in Example 1 to ensure that the resin completely impregnates the fiber;

[0046] S5, Cooling and shaping and pelletizing: Cooling water tank temperature 20℃, traction speed 1.2m / min, pelletizing length 10mm.

[0047] Example 3 (High glass fiber content, with ZrC+PPS synergistic modification)

[0048] 1. Formulation composition (percentage by mass)

[0049] Matrix resin: PPA 50%; Continuous alkali-free long glass fiber: 48%; Coupling agent (KH-550): 1.0% (based on glass fiber mass, i.e., 0.48% of total mass); Antioxidant system: Antioxidant 1010 0.2% + Antioxidant 168 0.1% (mass ratio 2:1); Lubricant: PE wax 0.3%; Synergistic modifying component: Nano ZrC 1% + PPS rigid chain 0.5% (total 1.5%); Other additives: Nucleating agent 0.2%.

[0050] 2. Preparation steps

[0051] S1, Raw material pretreatment: PPA resin, PPS rigid chain and nucleating agent are mixed and dried in a dehumidifying dryer at 120℃ for 4 hours, with a moisture content of 0.018% (180ppm).

[0052] S2, Fiber Guiding and Spreading: Glass fiber tension 8N, spread to 3.5 times the original width through 5 sets of gradient angle roller spreading devices;

[0053] S3, Resin Melting and Metering: Extruder Zone Temperatures: Zone 1 292℃, Zone 2 300℃, Zone 3 308℃, Zone 4 305℃, Zone 5 305℃, Zone 6 305℃, Die Head 312℃;

[0054] S4, melt impregnation: die pressure 15MPa, fiber tension 8N, to ensure complete impregnation with high glass fiber content;

[0055] S5, Cooling and shaping and pelletizing: Cooling water tank temperature 22℃, traction speed 1.0m / min, pelletizing length 12mm.

[0056] Comparative example (existing technology, short glass fiber reinforced PPA)

[0057] 1. Formulation composition (percentage by mass)

[0058] PPA 60%, short glass fiber (0.5-1mm in length) 40%, coupling agent KH-550 0.5%, antioxidant 1010 0.3%, calcium stearate 0.2%.

[0059] Performance testing

[0060] The materials prepared in Examples 1-3 and the comparative examples were subjected to performance tests according to the following standards, and the results are shown in the table below:

[0061] Tensile strength and elongation at break: GB / T1040.2-2006 (test speed 5mm / min);

[0062] Bending strength and bending modulus: GB / T9341-2008 (test speed 2mm / min);

[0063] Notched impact strength of simply supported beams: GB / T1043.1-2008 (23℃, notch type A);

[0064] Heat distortion temperature (HDT): GB / T1634.2-2004 (load 1.80MPa);

[0065] Interfacial shear strength: GB / T14074-2017.

[0066] Performance indicators Example 1 Example 2 Example 3 Comparative Example Tensile strength (MPa) 275 298 310 185 Bending strength (MPa) 282 310 335 220 Flexural modulus (GPa) 14.8 17.2 19.5 9.6 Notched impact strength of a simply supported beam (kJ / m²) 12.5 11.8 10.2 8.5 1.80 MPa heat distortion temperature (°C) 258 272 280 225 Interfacial shear strength (MPa) 42 48 51 28

[0067] As shown in the table above, compared with Example 1 and the comparative example, the present invention uses continuous long glass fiber reinforcement and optimized interface design (coupling agent KH-550), which increases tensile strength by 48.6%, flexural modulus by 54.2%, and interfacial shear strength by 50%, fully demonstrating the reinforcing advantages of continuous long glass fiber and the effectiveness of interface optimization.

[0068] In Example 2, after introducing nano-SiO2 and PPS rigid chain synergistic modification components, compared with Example 1, the flexural modulus increased by 16.2%, the heat distortion temperature increased by 5.4%, and the interfacial shear strength increased by 14.3%, indicating that the synergistic modification components can form a stable bond with the high-temperature nylon matrix and glass fiber, further optimizing rigidity and high-temperature resistance.

[0069] Example 3 uses 48% high glass fiber content and nano ZrC+PPS synergistic modification, and the mechanical strength and rigidity reach the peak (flexural modulus 19.5GPa), and the heat distortion temperature exceeds 280℃. Although the impact toughness is slightly reduced, it is still higher than that of the comparative example, meeting the stringent requirements of high-end structural components for high strength and high rigidity.

[0070] No defects such as bubbles or silver streaks were found in any of the embodiments. The wear of the equipment during processing was reduced by 30% compared with the prior art (as demonstrated by the screw wear test after continuous processing of 100kg of granules), proving the stability and processability of the preparation process of the present invention.

[0071] This invention effectively solves the technical pain points of existing high-temperature nylon reinforced materials, such as weak interfacial adhesion, insufficient impregnation, and limited performance, and possesses significant comprehensive advantages. In terms of formulation, it uses continuous alkali-free long glass fibers as the core reinforcement, combined with KH-550 coupling agent to construct a robust interface, increasing the interfacial shear strength by 50% compared to traditional short glass fiber materials. The introduction of nanoparticles and PPS rigid chains for synergistic modification results in a flexural modulus reaching up to 19.5 GPa and a heat distortion temperature exceeding 280℃, achieving a synergistic upgrade in rigidity and high-temperature resistance.

[0072] In terms of process, the customized impregnation die head and gradient yarn spreading design ensure complete fiber impregnation. Combined with precise drying and temperature control, it avoids defects such as bubbles and dry yarn in the finished product, and reduces equipment wear by 30%. The product has a balanced overall performance, with a maximum tensile strength of 310MPa. Its impact toughness is still superior to existing technologies even with high glass fiber content. It meets the high strength and high rigidity requirements of high-end scenarios such as automotive, electronics, and aerospace, while also having good processing fluidity. It broadens the application boundaries of high-temperature nylon materials and combines technological innovation with practical application value.

[0073] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A continuous long glass fiber reinforced high-temperature nylon material, characterized in that, The product comprises, by weight percentage, the following components: 50%-70% matrix resin, 30%-50% continuous alkali-free long glass fiber (E-Glass), 0.2%-1% coupling agent based on the weight of the continuous alkali-free long glass fiber, 0.2%-0.5% antioxidant system, 0.2%-0.8% lubricant, and 0-0.5% other additives; the matrix resin is high-temperature nylon, which is selected from at least one of polyphthalamide (PPA), PA6T, PA9T, and PA10T with a long-term service temperature ≥150℃.

2. The continuous long glass fiber reinforced high-temperature nylon material according to claim 1, characterized in that, The continuous alkali-free long glass fiber has a single filament diameter of 10-17 μm and a fiber bundle linear density of 2400-4800 tex.

3. The continuous long glass fiber reinforced high-temperature nylon material according to claim 1, characterized in that, The coupling agent is selected from aminosilane coupling agents.

4. The continuous long glass fiber reinforced high-temperature nylon material according to claim 4, characterized in that, The aminosilane coupling agent is KH-550.

5. The continuous long glass fiber reinforced high-temperature nylon material according to claim 1, characterized in that, The antioxidant system is a compound system of primary antioxidant and secondary antioxidant. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. The mass ratio of the primary antioxidant to the secondary antioxidant is (1:1) to (2:1).

6. The continuous long glass fiber reinforced high-temperature nylon material according to claim 1, characterized in that, The lubricant is selected from at least one of calcium stearate, silicone powder, polyethylene wax (PE wax), and pentaerythritol stearate.

7. The continuous long glass fiber reinforced high-temperature nylon material according to claim 1, characterized in that, It also includes a synergistic modification component, which is composed of nanoparticles and PPS rigid chains, wherein the nanoparticles are selected from at least one of SiO2 and ZrC; the total mass percentage of the synergistic modification component is 1%-5%.

8. A method for preparing a continuous long glass fiber reinforced high-temperature nylon material according to any one of claims 1-7, characterized in that, Includes the following steps: S1, Raw material pretreatment: Place the high-temperature nylon resin in a 120℃ forced-air drying oven or dehumidifying dryer and dry for 4-6 hours to reduce the resin moisture content to below 0.02% (200ppm); S2, Fiber Guiding and Spreading: The continuous alkali-free long glass fiber yarn is kept under constant tension by a tension control system, and then spread and thinned by multiple sets of roller-type spreading devices with adapted angles, so that the fiber bundle is loose and uniform. S3, Resin Melting and Metering: The dried high-temperature nylon resin, antioxidant system, lubricant, and other additives are added to a special impregnation screw extruder through a precision metering feeder. The heating temperature is set according to the melting point and melt index of the high-temperature nylon resin to melt and plasticize the resin. The processing temperature is controlled at 290℃-315℃. S4, Melt Impregnation: Molten resin is delivered to a customized impregnation die head, and simultaneously merged into the die head with the unfolded glass fiber bundle. The high-pressure melt inside the die head penetrates and tightly wraps each glass fiber monofilament. S5, Cooling and Pelletizing: The impregnated fiber / resin composite material is extruded from the die head and immediately sent to a cooling water tank for rapid cooling and solidification. Then, it is pulled at a constant speed by a traction roller and finally cut into 6-12 mm pellets by a pelletizer.