High-strength low-water-absorption nylon 66 composite material, preparation method and application thereof

Abstract

The application provides a high-strength low-water-absorption nylon 66 composite material and a preparation method and application thereof. The nylon 66 composite material comprises, in percentage by mass, PA66: 65-70%; glass fiber: 3-6%; flame retardant: 10-15%; toughening agent: 10-15%; antioxidant: 0.3-0.6%; lubricant: 0.3-0.6%; and ultraviolet resistant agent: 0.1-0.3%. The toughening agent is a copolymer of ethylene and octene; the PA66 comprises Shenma EPR27, Huafeng EP158 and Huafeng low-viscosity 66 EP1106; and the water absorption of the nylon 66 composite material is less than or equal to 0.28%. The nylon 66 composite material prepared by the formula has ultralow water absorption and high mechanical strength, and also has the flame retardant property due to the addition of the flame retardant. The application provides an effective way for the preparation of the high-toughness, high-strength and low-water-absorption nylon 66 composite material through formula optimization.

Description

Technical Field

[0001] This invention relates to the field of modified plastics technology, and in particular to a high-strength, low-absorption nylon 66 composite material, its preparation method, and its applications. Background Technology

[0002] Nylon (PA) 66 is a widely used engineering plastic, ranking first among the five major engineering plastics. It boasts advantages such as high strength, strong corrosion resistance, wear resistance, and good self-lubricating properties. However, due to the presence of hydrophilic amide groups in its molecular structure, PA66 differs from polyoxymethylene, polycarbonate, and acrylonitrile / butadiene / styrene copolymers (ABS) in that it exhibits strong water absorption, significantly affecting its mechanical properties. Furthermore, its various mechanical properties vary depending on the water absorption rate. This characteristic causes significant interference and deviation in the accurate measurement of PA66's mechanical properties and makes it unsuitable for use in humid environments.

[0003] In fixed environments, such as high-humidity environments, water absorption can affect the mechanical properties of materials, posing a risk to driving safety. For example, Chinese patent CN202210523740.8 describes a high flame-retardant PA66 composite material. This invention involves mixing PA66 resin, glass fiber, red phosphorus masterbatch, lubricant, modified aluminum hydroxide / expanded graphite composite, and antioxidant in a specific ratio to obtain a polymer. This polymer is then melted, mixed, and extruded using a twin-screw extruder. While this improves the flame-retardant properties of PA66, it does not solve the inherent defect of PA66's high water absorption. Reducing the PA66 content in the material can lower the water absorption rate, but this also reduces mechanical properties. Therefore, how to prepare a nylon 66 composite material that combines low water absorption and high mechanical properties is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, low-absorption nylon 66 composite material, its preparation method, and its application. This material overcomes the problem of high water absorption of polyamide, while possessing excellent mechanical properties and meeting the UL94-V0 flame retardant requirements.

[0005] To achieve the above objectives, this invention provides a nylon 66 composite material, comprising, by mass percentage: PA66: 65-70%; glass fiber: 3-6%; flame retardant: 10-15%; toughening agent: 10-15%; antioxidant: 0.3-0.6%; lubricant: 0.3-0.6%; and UV stabilizer: 0.1-0.3%. The toughening agent is a copolymer of ethylene and octene to improve the impact strength and elongation at break of the nylon 66 composite material. The PA66 includes Shenma EPR27, Huafeng EP158, and Huafeng low-viscosity 66 EP1106 to reduce the water absorption rate of the nylon 66 composite material, which is ≤0.28%. The nylon 66 composite material obtained according to the formulation of this invention possesses ultra-low water absorption and high mechanical strength. Furthermore, due to the addition of the flame retardant, it also possesses flame-retardant properties without affecting the mechanical properties of the composite material. This invention demonstrates that by combining these three types of PA66 with different mechanical and thermal properties, the polymer molecular chains can be more evenly distributed, thereby improving the density of the composite material and helping to reduce its water absorption; the addition of glass fiber also helps to reduce water absorption and improve strength.

[0006] Furthermore, the Shenma EPR27 has a tensile strength ≥75 MPa, an elongation at break of 46.2%, a flexural modulus of 1.8 GPa, and a notched cantilever beam impact strength of 7.9 kJ / m. 2 The melt flow rate is 10.8 g / 10 min; the heat distortion temperature is 82.9℃. The Huafeng EP158 has a tensile strength ≥75 MPa, an elongation at break of 46.2%, a flexural modulus of 2.5 GPa, and a notched cantilever beam impact strength of 5.8 kJ / m. 2 (2) Thermal properties: melt flow rate 9.1 g / 10 min, heat distortion temperature 65.1 ℃. The tensile strength of Huafeng Low Viscosity 66 EP1106 (from Huafeng Group Co., Ltd.) is ≥78 MPa, elongation at break is 42.5%, flexural modulus is 1.9 GPa, and cantilever beam notched impact strength is 7.2 kJ / m. 2 (2) Thermal properties: melt flow rate 11g / 10min, heat distortion temperature 78℃.

[0007] Furthermore, the percentages of Shenma EPR27, Huafeng EP158, and Huafeng Low Viscosity 66 EP1106 in the total mass of the nylon 66 composite material are 20-40%, 25-40%, and 8-20%, respectively, preferably 25-30%, 28-33%, and 15-20%, and more preferably 25-30%, 28-30%, and 15-20%.

[0008] Furthermore, the toughening agent is Exxon 6502. Using this toughening agent reduces the material's water absorption, while optimizing the formulation ensures the material's performance. Adjustments to the toughening agent and PA66 content in the formulation prevent batch molding defects caused by the temperature resistance of the flame retardant during injection molding.

[0009] Furthermore, the flame retardant is selected from 99.8% pure melamine; the use of high-performance flame retardants improves the fire resistance of the product and meets the fire protection requirements of the usage environment. And / or, the antioxidant is one or both of antioxidant 1098 or antioxidant 168. The lubricant of this invention can improve the gloss of the material surface, enhance the fluidity of the material, and also has the characteristics of good demolding and dispersion properties.

[0010] In some preferred embodiments, the nylon 66 composite material comprises, by weight percentage: Shenma EPR27: 22-28%; Huafeng EP158: 25-35%; Huafeng Low-Viscosity 66 EP1106: 15-20%; flame retardant: 12-15%; toughening agent POE: 10-12%; antioxidant: 0.3-0.6%; lubricant: 0.3-0.6%; and UV stabilizer: 0.1-0.3%. The nylon 66 composite material obtained according to this formulation has a water absorption rate as low as below 0.1% and a tensile strength as high as above 72 MPa.

[0011] Furthermore, by weight percentage, the composition includes: Shenma EPR27: 25%; Huafeng EP158: 30%; Huafeng Low-Viscosity 66EP1106: 18.8%; flame retardant: 15%; toughening agent POE: 10%; antioxidant: 0.5%; lubricant: 0.5%; and UV stabilizer: 0.2%. The nylon 66 composite material obtained according to this formulation has a water absorption rate as low as 0.05% and a tensile strength as high as 73 MPa.

[0012] Furthermore, the water absorption rate of the nylon 66 composite material is ≤0.2%, preferably ≤0.1%, more preferably ≤0.05%; and the tensile strength is ≥70MPa, preferably 70-90MPa.

[0013] The present invention also provides a method for preparing the nylon 66 composite material according to any one of the above claims, comprising the following steps: S1. The weighed PA66, glass fiber and toughening agent are put into a high-speed mixer and premixed at high speed for 15-25 minutes to obtain a well mixed resin. S2. The weighed antioxidant, lubricant, and UV stabilizer are added to the high-speed mixer and mixed at high speed for 60s to 300s to obtain a mixture. S3. The mixture is extruded and granulated using a twin-screw extruder. The mixture is then conveyed, melted, sheared, extruded, cooled, and granulated. Finally, it is cleaned, cooled, and dried to obtain the nylon 66 composite material.

[0014] This invention also provides an application of the nylon 66 composite material or the composite material obtained by the preparation method described above, for the preparation of railway fasteners, optical cable plastic fittings, and surge arrester accessories, such as for the preparation of railway leaky coaxial cables. This device exhibits excellent dimensional stability, high toughness, high strength, and low water absorption.

[0015] The beneficial effects of this invention are as follows: 1. The high-strength, low-absorption nylon 66 composite material provided by this invention has ultra-low water absorption and high mechanical strength through formula optimization. At the same time, due to the addition of flame retardant, it also has flame retardant properties. Therefore, it has excellent comprehensive performance and high application value.

[0016] 2. This invention uses a composite of three types of PA66 to make the polymer molecular chains more uniformly distributed, thereby improving the density of the composite material. The addition of glass fiber can further reduce its water absorption rate, while meeting the requirements of mechanical properties, vibration fatigue resistance, high and low temperature resistance, high flame retardancy, and environmental protection performance of the product. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] The raw materials used in this embodiment of the invention are sourced as follows: PA66 1 is Shenma EPR27 (from Shenma Engineering Plastics Co., Ltd.): (1) Mechanical information: tensile strength ≥80.2Mpa, elongation at break 35.2%, flexural modulus 1.8Gpa, cantilever beam notched impact strength 7.9kJ / m 2 (2) Thermal properties: melt flow rate 10.8 g / 10 min, heat distortion temperature 82.9 ℃.

[0019] PA66 2 is Huafeng EP158 (from Huafeng Group Co., Ltd.); (1) Mechanical information: tensile strength ≥75Mpa, elongation at break 46.2%, flexural modulus 2.5Gpa, cantilever beam notched impact strength 5.8kJ / m 2 (2) Thermal properties: melt flow rate 9.1 g / 10 min, heat distortion temperature 65.1 ℃.

[0020] PA66 3 is Huafeng Low Viscosity 66 EP1106 (from Huafeng Group Co., Ltd.); (1) Mechanical information: tensile strength ≥78Mpa, elongation at break 42.5%, flexural modulus 1.9Gpa, cantilever beam notched impact strength 7.2kJ / m 2 (2) Thermal properties: melt flow rate 11g / 10min, heat distortion temperature 78℃.

[0021] The flame retardant is selected from 99.8% pure melamine; the toughening agent is selected from Exxon 6502; the antioxidant is antioxidant 1098 with a melting temperature >100℃; the lubricant is selected from NC010 with a specific gravity of 1.15 g / cm³. 3 .

[0022] Examples 1-8 The formulations of the high-strength, low-absorption nylon 66 composite materials provided in Examples 1-7 are shown in Table 1. The preparation methods are as follows: S1. Weigh the PA66 1-3, glass fiber, and toughening agent into a high-speed mixer and mix them at high speed to obtain a well-mixed resin. S2. Add the weighed antioxidant, lubricant and UV stabilizer to the high-speed mixer and start mixing in the high-speed mixer for 200 seconds to ensure uniform mixing of the raw materials and obtain the mixture. S3. The mixture is extruded and granulated using a twin-screw extruder, then cleaned, cooled, dried, weighed, and packaged to obtain the high-strength, low-water-absorption PA66 composite material.

[0023] Table 1. Components and their percentage content in Examples 1-8 Raw material code Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 PA66 1 33% 28% 28% 23% 23% 26.8% 19% 28% PA66 2 33% 38% 28% 28% 26.8% 28% 32% 23% PA66 3 7.8% 7.8% 12.8% 17.8% 19% 14% 17.8% 17.8% Fiberglass 5% 5% 5% 5% 5% 5% 5% 5% Flame retardant 10% 10% 15% 15% 12% 12% 15% 15% toughening agent 10% 10% 10% 10% 13% 13% 10% 10% antioxidants 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% lubricant 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% UV protectant 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% The mechanical properties and water absorption rate testing methods of this invention are as follows: Tensile properties: Tested according to ISO 527-1-2012 standard, the tensile rate is 50 mm / min.

[0024] Notched impact performance of simply supported beams: tested according to ISO 179-1-2010 standard, with a strip thickness of 3.2 mm.

[0025] Determination of water absorption rate: The water absorption rate was tested according to GB1034-1998. The sample was cut into squares of 50±1 mm (sample thickness less than 25 mm), then dried in an oven at 50±2℃ for 24±1 h. After cooling to room temperature in a desiccator, the sample was weighed as m1. The sample was then immersed in distilled water at 23±0.5℃ for 24±1 h. After immersion, the sample was removed and the surface water was quickly wiped off with clean, dry filter paper. The sample was weighed again as m2. Water absorption rate W m The calculation formula is: .

[0026] Table 2 Performance Tests of Each Component in Examples 1-8 performance Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Tensile strength (MPa) 75 70 72 73 74 72 75 70 <![CDATA[Notched impact strength of simply supported beam (kJ / m 2 )]]> 4.5 5.0 5.3 5.5 5.6 5.3 4.5 5 Water absorption rate (%) 0.28 0.2 0.1 0.05 0.05 0.1 0.25 0.2 Table 2 shows that using three specific ratios of nylon 66 ensures that the nylon 66 composite material exhibits high strength and low water absorption. The effect is even better when the mass percentages of Shenma EPR27, Huafeng EP158, and Huafeng low-viscosity 66 EP1106 are 25-30%, 28-30%, and 15-20%, respectively. When the content of Shenma EPR27 or Huafeng EP158 is too high, the water absorption rate increases, indicating that the composite of the three PA66 types results in a more uniform distribution of polymer molecular chains, thereby improving the density of the composite material and further reducing its water absorption rate.

[0027] Comparative Examples 1-8 The formulations of the high-strength, low-absorption nylon 66 composite materials provided in Comparative Examples 1-8 are shown in Table 3. The preparation methods are the same as in Example 1.

[0028] Table 3. Components and their percentage content in Comparative Examples 1-8 Raw material code Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 PA66 1 0% 40.8% 52% 66.8% 0% 0% 23% 25% PA66 2 52% 28% 0% 0% 66.8% 0% 28% 30% PA66 3 16.8% 0% 16.8% 0% 0% 66.8% 17.8% 18.8% Fiberglass 5% 5% 5% 5% 5% 5% 5% 0% Flame retardant 15% 15% 15% 15% 15% 15% 15% 15% toughening agent 10% 10% 10% 12% 12% 12% 0% 10% antioxidants 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% lubricant 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% UV protectant 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% Table 4 Performance Tests of Each Component in Comparative Examples 1-8 performance Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Tensile strength (MPa) 64 64 65 66 67 64 68 64 <![CDATA[Notched impact strength of simply supported beam (kJ / m 2 )]]> 4.1 4.0 4.2 3.0 3.9 4.2 4.3 4.2 Water absorption rate (%) 0.31 0.28 0.30 0.26 0.8 0.25 0.22 0.26 As shown in Table 4, when only one or two types of PA66 are used, the tensile strength and notched impact strength of simply supported beams decrease to varying degrees, while the water absorption rate increases. When the toughening agent content is 0%, the moisture absorption rate increases significantly.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength, low-water-absorption nylon 66 composite material, characterized in that, By weight percentage, it includes PA66: 65-70%; glass fiber: 3-6%; flame retardant: 10-15%; Toughening agent: 10-15%; Antioxidant: 0.3-0.6%; Lubricant: 0.3-0.6%; UV stabilizer: 0.1-0.3%; the toughening agent is a copolymer of ethylene and octene to improve the impact strength and elongation at break of the nylon 66 composite material; the PA66 comprises a blend of Shenma EPR27, Huafeng EP158, and Huafeng Low-Viscosity 66 EP1106, and the water absorption rate of the nylon 66 composite material is ≤0.28%; the percentages of Shenma EPR27, Huafeng EP158, and Huafeng Low-Viscosity 66 EP1106 in the total mass of the nylon 66 composite material are 20-40%, 25-40%, and 8-20%, respectively.

2. The high-strength, low-water-absorption nylon 66 composite material according to claim 1, characterized in that, The Shenma EPR27 has a flexural modulus of 1.8 GPa and a melt flow rate of 10.8 g / 10 min; the Huafeng EP158 has a flexural modulus of 2.5 GPa and a melt flow rate of 9.1 g / 10 min; and the Huafeng Low Viscosity 66 EP1106 has a flexural modulus of 1.9 GPa and a melt flow rate of 11 g / 10 min.

3. The high-strength, low-water-absorption nylon 66 composite material according to claim 1, characterized in that, The toughening agent is Exxon 6502.

4. The high-strength, low-water-absorption nylon 66 composite material according to claim 1, characterized in that, The flame retardant is melamine; and / or, the antioxidant is one or both of antioxidant 1098 or antioxidant 168.

5. The high-strength, low-water-absorption nylon 66 composite material according to claim 1, characterized in that, By weight percentage, it includes: Shenma EPR27: 22-28%; Huafeng EP158: 25-35%; Huafeng Low Viscosity 66 EP1106: 15-20%; Flame retardant: 12-15%; Toughening agent POE: 10-12%; Antioxidant: 0.3-0.6%; Lubricant: 0.3-0.6%; UV protectant: 0.1-0.3%; Fiberglass: 3-6%.

6. The high-strength, low-water-absorption nylon 66 composite material according to any one of claims 1-5, characterized in that, The nylon 66 composite material has a water absorption rate of ≤0.2% and a tensile strength of ≥70MPa.

7. A method for preparing a high-strength, low-water-absorption nylon 66 composite material according to any one of claims 1-6, characterized in that, Includes the following steps: S1. The weighed PA66, glass fiber and toughening agent are put into a high-speed mixer and premixed at high speed for 15-25 minutes to obtain a well mixed resin. S2. The weighed antioxidant, lubricant, and UV stabilizer are added to the high-speed mixer and mixed at high speed for 60s to 300s to obtain a mixture. S3. The mixture is extruded and granulated using a twin-screw extruder. The mixture is then conveyed, melted, sheared, extruded, cooled, and granulated. Finally, it is cleaned, cooled, and dried to obtain the nylon 66 composite material.

8. The application of a high-strength, low-water-absorption nylon 66 composite material according to any one of claims 1-6 or a nylon 66 composite material obtained by the preparation method according to claim 7, characterized in that, The nylon 66 composite material is used in the preparation of railway fasteners, optical cable plastic fittings, and surge arrester accessories.