Low-water-absorption toughened nylon 6 and preparation method thereof

Abstract

The invention relates to the technical field of nylon 6 materials, in particular to low-water-absorption toughened nylon 6 and a preparation method thereof. The low-water-absorption toughened nylon 6 is prepared from the following raw materials in parts by mass: 80 to 120 parts of nylon 6, 10 to 30 parts of polyhexamethylene adipamide, 1 to 3 parts of acrylonitrile-butadiene-styrene copolymer, 10 to 20 parts of alkali-free glass fiber, 1 to 5 parts of nano silicon dioxide, 1 to 5 parts of nano layered silicate, 1 to 2 parts of silane coupling agent, 1 to 3 parts of polytetrafluoroethylene and 1 to 3 parts of tri (2, 2, 6-trimethyl-1, 3-pentanediol monoisobutyrate). The material is prepared from the following components in parts by weight: 0.1-1 part of 2, 4-di-tert-butylphenyl) phosphite ester, 0.1-1 part of silicone master batch, 1-2 parts of compatilizer and 1-3 parts of antioxidant. A plurality of raw materials are matched in an interface area to form a compact barrier, and water absorption is jointly inhibited. Meanwhile, the toughness and the impact resistance of the material are synergistically improved, and the dual goals of reducing the water absorption rate and enhancing the mechanical property are achieved.

Description

Technical Field

[0001] This invention relates to the field of nylon 6 material technology, and in particular to a low-water-absorption toughened nylon 6 and its preparation method. Background Technology

[0002] Polyamide, commonly known as nylon, or PA for short, is a general term for a class of thermoplastic resins whose molecular backbone contains repeating amide groups. Polyamide 6 (Nylon 6, PA6) is characterized by its lower melting point and wider processing temperature range, and its impact resistance and solvent resistance are superior to those of nylon 66. Therefore, nylon 6 has been widely used in various industrial fields such as petrochemicals, defense, machinery manufacturing, and textiles, becoming an important engineering plastic.

[0003] Currently, nylon 6 is typically a translucent or opaque milky-white semi-crystalline resin. It exhibits high rigidity and toughness over a wide temperature range. However, due to the high density of hydrophilic amide groups in its molecular structure, nylon 6 possesses significant water absorption properties. Specifically, nylon 6 has a high water absorption rate, a characteristic that negatively impacts its material properties in several ways.

[0004] First, water absorption significantly reduces the toughness of nylon 6. During the water absorption process, water molecules penetrate between the molecular chains of nylon 6, disrupting the intermolecular forces and thus reducing the material's toughness and impact resistance, affecting its reliability and durability in practical applications.

[0005] Secondly, the high moisture absorption rate of nylon 6 also results in a large molding shrinkage rate. During the molding process, the presence of moisture causes nylon 6 to shrink unevenly upon cooling, thus affecting the dimensional stability of the product and causing many inconveniences for subsequent processing and application.

[0006] These current issues limit the application of nylon 6 in high-end engineering fields, especially in applications requiring high material performance. Therefore, developing a nylon 6 composite material that can effectively reduce water absorption, improve toughness and mechanical strength, and enhance molding shrinkage and dimensional stability is of significant practical importance and application value. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by proposing a low-absorption toughened nylon 6 and its preparation method.

[0008] A low-water-absorption toughened nylon 6, the raw materials of which include, by weight: 80-120 parts nylon 6, 10-30 parts polyhexamethylene adipamide, 1-3 parts acrylonitrile-butadiene-styrene copolymer, 10-20 parts alkali-free glass fiber, 1-5 parts nano silica, 1-5 parts nano-layered silicate, 1-2 parts silane coupling agent, 1-3 parts polytetrafluoroethylene, 0.1-1 parts tris(2,4-di-tert-butylphenyl) phosphite, 0.1-1 parts silicone masterbatch, 1-2 parts compatibilizer, and 1-3 parts antioxidant.

[0009] Preferably, the alkali-free glass fiber is a short-cut glass fiber with a single filament diameter of 10-20 μm.

[0010] Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0011] Preferably, the compatibilizer is a maleic anhydride-grafted ethylene-acrylate copolymer.

[0012] Preferably, the nanolayered silicate is nano-montmorillonite with a fineness of 300 mesh and a specific surface area of ​​40-80 m². 2 / g.

[0013] Preferably, the antioxidant includes: antioxidant 1098 and / or antioxidant 168.

[0014] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in the working gas and treat it with low-temperature plasma for 10-20 minutes to obtain pretreated glass fiber. S2. Disperse nano-silica and nano-layered silicate in an ethanol aqueous solution, and perform ultrasonic treatment for 10-30 min under stirring. Then add silane coupling agent and stir for 10-30 min to obtain a suspension. Immerse the pretreated glass fiber in the suspension and continue stirring for 1-2 h. Filter, wash, and vacuum dry to obtain composite glass fiber. S3. After drying Nylon 6, mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, compatibilizer, and antioxidant, and then mix at 140-160℃ for 5-14 minutes; then add composite glass fiber and extrude.

[0015] Preferably, in S1, the working gas flow rate is 300-600 mL / min, and the working gas includes oxygen and argon, with the flow rate ratio of oxygen to argon being 1-2:5-10.

[0016] Preferably, in S2, the ultrasonic power is 200-400W and the ultrasonic frequency is 50-70kHz.

[0017] Preferably, in S3, a twin-screw extruder is used for melt blending extrusion, with a melt temperature of 250-260℃ and a screw speed of 200-400 r / min.

[0018] Beneficial effects: This invention utilizes plasma treatment to introduce active groups onto the surface of glass fibers, thereby optimizing the microstructure of the fiber surface and significantly increasing the surface energy. This provides binding sites for the subsequent adsorption of nano-silica and nano-layered silicates. The particle-shaped nano-silica forms a uniformly dispersed granular layer on the glass fiber surface, effectively blocking water penetration. Meanwhile, the nano-layered silicates form ordered sheets on the fiber surface through intercalation structures, further extending the diffusion path of water molecules. The synergistic effect of the two nanomaterials significantly improves the interfacial bonding strength and barrier properties of the composite material.

[0019] This invention utilizes nano-layered silicates to form an intercalation structure within a nylon 6 matrix, effectively extending the diffusion path of water molecules. Simultaneously, the hydrophobic properties of polytetrafluoroethylene (PTFE) create a low surface energy barrier on the composite material surface, hindering water penetration. Furthermore, the chemical bonds formed at the interface by the silane coupling agent reduce the accessibility of hydrophilic groups, thereby significantly reducing the material's water absorption.

[0020] This invention utilizes plasma-activated glass fibers to form a strong interfacial bond with a nylon 6 matrix. A composite modified layer of nano-silica and nano-layered silicates forms a dense barrier in the interfacial region, jointly inhibiting moisture absorption. Simultaneously, the rigid framework of the nanomaterials effectively disperses stress, and combined with acrylonitrile-butadiene-styrene copolymer as an elastomer, both synergistically enhance the material's toughness and impact resistance, achieving the dual goals of reducing water absorption and enhancing mechanical properties.

[0021] This invention effectively suppresses the thermal motion of nylon 6 molecular chains through the rigid framework of glass fiber and nanofillers, reducing molding shrinkage, and the cross-linked network formed in the interface region restricts the relaxation process of molecular chains, thereby improving the dimensional accuracy of the product and meeting the needs of high-end engineering applications. Attached Figure Description

[0022] Figure 1 The graph shows a comparison of the tensile strength and elongation at break of the low-absorption toughened nylon 6 obtained in Example 5 and Comparative Examples 1-2.

[0023] Figure 2 The graph shows a comparison of the notched impact strength and 24-hour water absorption rate of the low-water-absorption toughened nylon 6 obtained in Example 5 and Comparative Examples 1-2. Detailed Implementation

[0024] The present invention will be further explained below with reference to specific embodiments.

[0025] The following Nylon 6 used is sourced from Yueyang Baling Petrochemical, grade PA6 YH800. The following Polyhexamethylene adipamide used is sourced from DuPont, USA, grade PA66 8018. The following Acrylonitrile-Butadiene-Styrene copolymer used is sourced from Chi Mei, grade ABS PA-757. The following Polytetrafluoroethylene used is sourced from DuPont, USA, grade PTFE 7C X. The following Silicone Masterbatch used is sourced from Dow Corning, grade MB50-002. The following Maleic anhydride-grafted ethylene-acrylate copolymer used is sourced from SK, South Korea, grade LOTADER. ® 4403. The alkali-free glass fibers used below have a diameter of 15±2 μm and a length of 6 mm. The nano-montmorillonite used below has a fineness of 300 mesh and a specific surface area of ​​50 m². 2 / g.

[0026] Example 1 A low-water-absorption toughened nylon 6, the raw materials of which include: 800g of nylon 6, 100g of polyhexamethylene adipamide, 10g of acrylonitrile-butadiene-styrene copolymer, 100g of alkali-free glass fiber, 10g of nano-silica, 10g of nano-montmorillonite, 10g of γ-aminopropyltriethoxysilane, 10g of polytetrafluoroethylene, 1g of tris(2,4-di-tert-butylphenyl) phosphite, 1g of silicone masterbatch, 10g of maleic anhydride-grafted ethylene-acrylate copolymer, and 10g of antioxidant 1098.

[0027] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in a plasma reactor and treat it with low-temperature plasma for 10 minutes under a working gas (flow rate of 300 mL / min, composed of oxygen and argon in a flow rate ratio of 1:5). The low-temperature plasma treatment power is 300 W to obtain pretreated glass fiber. S2. Disperse nano-silica and nano-montmorillonite in 400g of 50% ethanol aqueous solution, and perform ultrasonic treatment for 10min with stirring at a speed of 100r / min, an ultrasonic power of 200W, and an ultrasonic frequency of 50kHz. Then add γ-aminopropyltriethoxysilane and stir at 100r / min for 10min to obtain a suspension. Immerse the pretreated glass fiber in the suspension and continue stirring for 1h. Filter, wash, and vacuum dry at 60℃ for 4h to obtain composite glass fiber. S3. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 1098. Mix the mixture at 140°C for 5 minutes at a speed of 40 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 250°C, and the screw speed is 200 r / min.

[0028] Example 2 A low-water-absorption toughened nylon 6, the raw materials of which include: 1200g nylon 6, 300g polyhexamethylene adipamide, 30g acrylonitrile-butadiene-styrene copolymer, 200g alkali-free glass fiber, 50g nano silica, 50g nano montmorillonite, 20g γ-aminopropyltriethoxysilane, 30g polytetrafluoroethylene, 10g tris(2,4-di-tert-butylphenyl) phosphite, 10g silicone masterbatch, 20g maleic anhydride-grafted ethylene-acrylate copolymer, and 30g antioxidant 1098.

[0029] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in a plasma reactor and treat it with low-temperature plasma for 20 minutes under a working gas (flow rate of 600 mL / min, composed of oxygen and argon in a flow rate ratio of 2:10). The low-temperature plasma treatment power is 600 W to obtain pretreated glass fiber. S2. Nano-silica and nano-montmorillonite are dispersed in 800g of 70% ethanol aqueous solution. The mixture is then subjected to ultrasonic treatment for 30min with stirring at a speed of 500r / min, an ultrasonic power of 400W, and an ultrasonic frequency of 70kHz. γ-aminopropyltriethoxysilane is then added and stirred at 500r / min for 30min to obtain a suspension. The pretreated glass fiber is immersed in the suspension and stirred for 2h. After filtration and washing, the fiber is vacuum dried at 80℃ for 8h to obtain composite glass fiber. S3. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 1098. Mix the mixture at 160°C for 14 minutes at a speed of 60 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 260°C, and the screw speed is 400 r / min.

[0030] Example 3 A low-water-absorption toughened nylon 6, the raw materials of which include: 900g nylon 6, 250g polyhexamethylene adipamide, 15g acrylonitrile-butadiene-styrene copolymer, 180g alkali-free glass fiber, 20g nano silica, 40g nano montmorillonite, 12g γ-aminopropyltriethoxysilane, 25g polytetrafluoroethylene, 2g tris(2,4-di-tert-butylphenyl) phosphite, 7g silicone masterbatch, 13g maleic anhydride-grafted ethylene-acrylate copolymer, and 25g antioxidant 168.

[0031] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in a plasma reactor and treat it with low-temperature plasma for 15 minutes under a working gas (flow rate of 375 mL / min, composed of oxygen and argon in a flow rate ratio of 1.5:6). The low-temperature plasma treatment power is 500 W to obtain pretreated glass fiber. S2. Nano-silica and nano-montmorillonite are dispersed in 500g of 65% ethanol aqueous solution. The mixture is subjected to ultrasonic treatment for 15min with stirring at a speed of 400r / min, an ultrasonic power of 250W, and an ultrasonic frequency of 65kHz. Then, γ-aminopropyltriethoxysilane is added and the mixture is stirred at 200r / min for 25min to obtain a suspension. The pretreated glass fiber is immersed in the suspension and stirred for another 80min. The mixture is then filtered, washed, and vacuum dried at 75℃ for 5h to obtain composite glass fiber. S3. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 168. Mix the mixture at 155°C for 6 minutes at a speed of 55 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 252°C, and the screw speed is 350 r / min.

[0032] Example 4 A low-water-absorption toughened nylon 6, the raw materials of which include: 1100g nylon 6, 150g polyhexamethylene adipamide, 25g acrylonitrile-butadiene-styrene copolymer, 120g alkali-free glass fiber, 40g nano silica, 20g nano montmorillonite, 18g γ-aminopropyltriethoxysilane, 15g polytetrafluoroethylene, 8g tris(2,4-di-tert-butylphenyl) phosphite, 3g silicone masterbatch, 17g maleic anhydride-grafted ethylene-acrylate copolymer, and 15g antioxidant 168.

[0033] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in a plasma reactor and treat it with low-temperature plasma for 15 minutes under a working gas (flow rate of 475 mL / min, composed of oxygen and argon in a flow rate ratio of 1.5:8). The low-temperature plasma treatment power is 400 W to obtain pretreated glass fiber. S2. Nano-silica and nano-montmorillonite were dispersed in 700g of 55% ethanol aqueous solution. The mixture was subjected to ultrasonic treatment for 25min with stirring at a speed of 200r / min, an ultrasonic power of 350W, and an ultrasonic frequency of 55kHz. Then, γ-aminopropyltriethoxysilane was added and the mixture was stirred at 400r / min for 15min to obtain a suspension. The pretreated glass fiber was immersed in the suspension and stirred for another 100min. The mixture was then filtered, washed, and vacuum dried at 65℃ for 7h to obtain composite glass fiber. S3. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 168. Mix the mixture at 145°C for 12 minutes at a speed of 45 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 258°C, and the screw speed is 250 r / min.

[0034] Example 5 A low-water-absorption toughened nylon 6, the raw materials of which include: 1000g nylon 6, 200g polyhexamethylene adipamide, 20g acrylonitrile-butadiene-styrene copolymer, 150g alkali-free glass fiber, 30g nano silica, 30g nano montmorillonite, 15g γ-aminopropyltriethoxysilane, 20g polytetrafluoroethylene, 5g tris(2,4-di-tert-butylphenyl) phosphite, 5g silicone masterbatch, 15g maleic anhydride-grafted ethylene-acrylate copolymer, and 20g antioxidant 168.

[0035] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in a plasma reactor and treat it with low-temperature plasma for 15 minutes under a working gas (flow rate of 425 mL / min, composed of oxygen and argon in a flow rate ratio of 1.5:7). The low-temperature plasma treatment power is 450 W to obtain pretreated glass fiber. S2. Nano-silica and nano-montmorillonite are dispersed in 600g of 60% (w / w) ethanol aqueous solution. The mixture is then subjected to ultrasonic treatment for 20min with stirring at 300r / min, ultrasonic power at 300W, and ultrasonic frequency at 60kHz. γ-aminopropyltriethoxysilane is then added and stirred at 300r / min for 20min to obtain a suspension. The pretreated glass fiber is immersed in the suspension and stirred for another 90min. The mixture is then filtered, washed, and vacuum dried at 70℃ for 6h to obtain composite glass fiber. S3. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 168. Mix the mixture at 150°C for 9 minutes at a speed of 50 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 255°C, and the screw speed is 300 r / min.

[0036] Comparative Example 1 A low-water-absorption toughened nylon 6, the raw materials of which include: 1000g nylon 6, 200g polyhexamethylene adipamide, 20g acrylonitrile-butadiene-styrene copolymer, 150g alkali-free glass fiber, 30g nano silica, 30g nano montmorillonite, 15g γ-aminopropyltriethoxysilane, 20g polytetrafluoroethylene, 5g tris(2,4-di-tert-butylphenyl) phosphite, 5g silicone masterbatch, 15g maleic anhydride-grafted ethylene-acrylate copolymer, and 20g antioxidant 168.

[0037] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Nano-silica and nano-montmorillonite are dispersed in 600g of 60% (w / w) ethanol aqueous solution. The mixture is subjected to ultrasonic treatment for 20min with stirring at a speed of 300r / min, an ultrasonic power of 300W, and an ultrasonic frequency of 60kHz. Then, γ-aminopropyltriethoxysilane is added and stirred at 300r / min for 20min to obtain a suspension. Alkali-free glass fiber is immersed in the suspension and stirred for another 90min. The mixture is then filtered, washed, and vacuum dried at 70℃ for 6h to obtain composite glass fiber. S2. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 168. Mix the mixture at 150°C for 9 minutes at a speed of 50 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 255°C, and the screw speed is 300 r / min.

[0038] Comparative Example 2 A low-absorption, toughened nylon 6, the raw materials of which include: 1000g nylon 6, 200g polyhexamethylene adipamide, 20g acrylonitrile-butadiene-styrene copolymer, 210g alkali-free glass fiber, 15g γ-aminopropyltriethoxysilane, 20g polytetrafluoroethylene, 5g tris(2,4-di-tert-butylphenyl) phosphite, 5g silicone masterbatch, 15g maleic anhydride-grafted ethylene-acrylate copolymer, and 20g antioxidant 168.

[0039] The preparation method of the above-mentioned low water absorption toughened nylon 6 includes the following steps: S1. Place the alkali-free glass fiber in a plasma reactor and treat it with low-temperature plasma for 15 minutes under a working gas (flow rate of 425 mL / min, composed of oxygen and argon in a flow rate ratio of 1.5:7). The low-temperature plasma treatment power is 450 W to obtain pretreated glass fiber. S2. Add γ-aminopropyltriethoxysilane to 600g of 60% ethanol aqueous solution and stir at 300r / min for 20min to obtain a suspension; immerse the pretreated glass fiber in the suspension and continue stirring for 90min, filter, wash, and vacuum dry at 70℃ for 6h to obtain composite glass fiber. S3. Dry nylon 6 and mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, maleic anhydride-grafted ethylene-acrylate copolymer, and antioxidant 168. Mix the mixture at 150°C for 9 minutes at a speed of 50 r / min. Then, feed the mixture into a twin-screw extruder for melt blending until homogeneous. The composite glass fiber is fed from the side feeder of the twin-screw extruder. The melt temperature in each zone is 255°C, and the screw speed is 300 r / min.

[0040] The tensile strength and elongation at break of the low-absorption toughened nylon 6 obtained in Example 5 and Comparative Examples 1-2 were determined in accordance with GB / T 1040.4-2006 "Determination of tensile properties of plastics - Part 4: Test conditions for isotropic and orthotropic fiber-reinforced composites".

[0041] like Figure 1 As shown, the low water absorption toughened nylon 6 obtained in Example 5 has the highest tensile strength and the lowest elongation at break, which is significantly better than the comparative example.

[0042] The notched impact strength (notch type A) of the low-absorption toughened nylon 6 obtained in Example 5 and Comparative Examples 1-2 was determined according to GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams". The 24-hour water absorption rate (23℃) of the low-absorption toughened nylon 6 obtained in Example 5 and Comparative Examples 1-2 was also determined.

[0043] like Figure 2 As shown, the low-water-absorption toughened nylon 6 obtained in Example 5 has the highest cantilever beam notched impact strength and the lowest water absorption rate, which is significantly better than the comparative example.

[0044] The reasons for the above results are as follows: This invention utilizes plasma treatment to introduce active groups on the surface of glass fibers, optimizing the microstructure of the fiber surface and significantly increasing surface energy. This provides binding sites for the subsequent adsorption of nano-silica and nano-layered silicates. The particle-like nano-silica forms a uniformly dispersed granular layer on the glass fiber surface, effectively blocking water penetration. The nano-layered silicates, through intercalation, form ordered sheets on the fiber surface, further extending the diffusion path of water molecules. The synergistic effect of these two nanomaterials significantly improves the interfacial bonding strength and barrier performance of the composite material. This invention utilizes nano-layered silicates to form an intercalation structure in the nylon 6 matrix, effectively extending the diffusion path of water molecules. Simultaneously, the hydrophobic properties of polytetrafluoroethylene form a low surface energy barrier on the composite material surface, hindering water penetration. The chemical bonds formed by the silane coupling agent at the interface reduce the accessibility of hydrophilic groups, thereby significantly reducing the material's water absorption. This invention uses plasma-activated glass fibers to form a strong interfacial bond with the nylon 6 matrix. The composite modified layer of nano-silica and nano-layered silicates forms a dense barrier in the interfacial region, jointly inhibiting water absorption. Meanwhile, the rigid framework of nanomaterials effectively disperses stress, and when combined with acrylonitrile-butadiene-styrene copolymer as an elastomer, the two work synergistically to improve the toughness and impact resistance of the material, achieving the dual goals of reducing water absorption and enhancing mechanical properties.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A low-absorption, toughened nylon 6, characterized in that, The raw materials, by weight, include: 80-120 parts of nylon 6, 10-30 parts of polyhexamethylene adipamide, 1-3 parts of acrylonitrile-butadiene-styrene copolymer, 10-20 parts of alkali-free glass fiber, 1-5 parts of nano-silica, 1-5 parts of nano-layered silicate, 1-2 parts of silane coupling agent, 1-3 parts of polytetrafluoroethylene, 0.1-1 parts of tris(2,4-di-tert-butylphenyl) phosphite, 0.1-1 parts of silicone masterbatch, 1-2 parts of compatibilizer, and 1-3 parts of antioxidant.

2. The low-absorption, toughened nylon 6 according to claim 1, characterized in that, Alkali-free glass fiber is a short-cut glass fiber with a single filament diameter of 10-20μm.

3. The low-absorption, toughened nylon 6 according to claim 1, characterized in that, The silane coupling agent is γ-aminopropyltriethoxysilane.

4. The low-absorption, toughened nylon 6 according to claim 1, characterized in that, The compatibilizer is a maleic anhydride-grafted ethylene-acrylate copolymer.

5. The low-absorption, toughened nylon 6 according to claim 1, characterized in that, Nanolayered silicate is nano-montmorillonite with a fineness of 300 mesh and a specific surface area of ​​40-80 m². 2 / g.

6. The low-absorption, toughened nylon 6 according to claim 1, characterized in that, Antioxidants include: Antioxidant 1098 and / or Antioxidant 168.

7. A method for preparing low-absorption toughened nylon 6 as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Place the alkali-free glass fiber in the working gas and treat it with low-temperature plasma for 10-20 minutes to obtain pretreated glass fiber. S2. Disperse nano-silica and nano-layered silicate in an ethanol aqueous solution, and treat with ultrasound for 10-30 min under stirring. Then add silane coupling agent and stir for 10-30 min to obtain a suspension. The pretreated glass fibers were immersed in the suspension and stirred for 1-2 hours, then filtered, washed, and vacuum dried to obtain composite glass fibers. S3. After drying Nylon 6, mix it with polyhexamethylene adipamide, acrylonitrile-butadiene-styrene copolymer, polytetrafluoroethylene, tris(2,4-di-tert-butylphenyl) phosphite, silicone masterbatch, compatibilizer, and antioxidant, and then mix at 140-160℃ for 5-14 minutes; then add composite glass fiber and extrude.

8. The method for preparing low-absorption toughened nylon 6 according to claim 7, characterized in that, In S1, the working gas flow rate is 300-600 mL / min, and the working gas includes oxygen and argon, with a flow rate ratio of 1-2:5-10.

9. The method for preparing low-absorption toughened nylon 6 according to claim 7, characterized in that, In S2, the ultrasonic power is 200-400W and the ultrasonic frequency is 50-70kHz.

10. The method for preparing low-absorption toughened nylon 6 according to claim 7, characterized in that, In S3, a twin-screw extruder is used for melt blending extrusion, with a melt temperature of 250-260℃ and a screw speed of 200-400 r / min.

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