A highly stable quick-connect joint material for nylon pipes and its preparation method

Abstract

The present invention relates to the technical field of quick-connect fitting materials, and specifically discloses a high-stability nylon tube quick-connect fitting material and a preparation method thereof. The raw materials of the above-mentioned high-stability nylon tube quick-connect fitting material include, by mass: 50-100 parts of nylon 12, 5-10 parts of nylon 66, 1-3 parts of graphene oxide, 5-10 parts of styrene, 2-5 parts of maleic anhydride, 0.1-0.2 parts of initiator, 5-10 parts of polyethylene, 1-2 parts of polyethylene-maleic anhydride, 1-2 parts of triphenyl phosphite, 1-2 parts of lubricant, 1-2 parts of waterproof agent, and 1-2 parts of antioxidant. After molding, the oxygen index of the product of the present invention can not only reach more than 38.6%, and the flame retardant grade can reach the V-0 grade of UL-94. At the same time, it has high mechanical strength and is not prone to brittle fracture during long-term use. Moreover, the process is simple and the reaction conditions are mild, which is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of quick - connect fitting materials, and particularly relates to a high - stability nylon tube quick - connect fitting material and a preparation method thereof. Background Art

[0002] As an engineering plastic, nylon has many excellent properties such as excellent wear resistance, self - lubricity, mechanical properties, acid and alkali resistance, etc. The usage amount of nylon in actual work and life ranks first among engineering plastics. Nylon has excellent performance and many excellent characteristics that cannot be compared with many metal materials. It is widely used in various fields at home and abroad, replacing the metal materials used in many products, and the market share has increased significantly.

[0003] A quick - connect fitting is a fitting that can quickly achieve the connection or disconnection of pipelines. It is a widely used component in the mechanical equipment industry, and its constituent materials are generally divided into plastics, stainless steel, copper, aluminum, etc. Nylon tubes have corrosion resistance, long service life, lower cost than metal tubes, and are easy to install, reliable, and beautiful by themselves, and are widely used in quick - connect fittings.

[0004] However, due to the characteristics of the nylon molecular structure, not only is the flame retardancy poor, but also its hydrophilicity is strong, resulting in a significant decline in the strength, toughness, and mechanical strength of nylon pipes. At the same time, nylon tubes also have the defect of being easily bent and deformed, unable to meet the requirements of mass production, and are prone to brittle fracture during long - term use, unable to meet the requirements of industries with high reliability requirements. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies existing in the prior art, and to provide a high - stability nylon tube quick - connect fitting material and a preparation method thereof.

[0006] A high - stability nylon tube quick - connect fitting material, the raw materials of which by mass fraction include: 50 - 100 parts of nylon 12, 5 - 10 parts of nylon 66, 1 - 3 parts of graphene oxide, 5 - 10 parts of styrene, 2 - 5 parts of maleic anhydride, 0.1 - 0.2 parts of initiator, 5 - 10 parts of polyethylene, 1 - 2 parts of polyethylene - maleic anhydride, 1 - 2 parts of triphenyl phosphite, 1 - 2 parts of lubricant, 1 - 2 parts of waterproof agent, and 1 - 2 parts of antioxidant.

[0007] Preferably, the initiator is azobisisobutyronitrile.

[0008] Preferably, the lubricant is at least one of butyl stearate, ethylene bisstearamide, liquid paraffin, polyethylene wax, and polypropylene wax.

[0009] Preferably, the waterproof agent is at least one of aluminum hydroxide, polysiloxane, glass microspheres, and calcium stearate.

[0010] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0011] The preparation method of the above high-stability nylon tube quick-insert joint material includes the following steps:

[0012] S1. Add graphene oxide and styrene to a solvent, ultrasonically treat for 10 - 30 min, add maleic anhydride and an initiator thereto, stir at 60 - 80 °C for 1 - 2 h, remove the solvent, wash, and vacuum dry to obtain a graphene-styrene graft;

[0013] S2. Add nylon 66 to a formic acid solution, stir at 60 - 70 °C for 1 - 2 h, add the graphene-styrene graft thereto and stir for 10 - 30 min, cool down to -50 to -80 °C, freeze for 1 - 2 h, vacuum dry for 20 - 30 h with a vacuum degree of 10 - 50 Pa to obtain pretreated nylon 66;

[0014] S3. Blend nylon 12 and pretreated nylon 66, extrude and pelletize, and dry; then add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, a lubricant, a waterproof agent, and an antioxidant, and melt-extrude and draw into shape.

[0015] Preferably, in S1, the ultrasonic frequency is 5 - 10 kHz.

[0016] Preferably, in S1, the solvent is toluene or xylene.

[0017] Preferably, in S3, the melting temperature is 200 - 230 °C.

[0018] Preferably, in S3, during the drawing and forming process, the draw ratio is 1.1 - 1.2, and the sizing sleeve is evacuated to 0.01 - 0.05 MPa.

[0019] Beneficial effects:

[0020] If graphene oxide is directly added to nylon resin, it is very easy to exist in the form of stress concentration point defects, thus greatly reducing the strength and flame retardant performance of the product.

[0021] However, in the present invention, by preparing the graphene-styrene graft, the agglomeration phenomenon of graphene oxide can be effectively avoided, and the interfacial interaction between graphene oxide and the nylon matrix can be improved, enhancing the mechanical properties of the composite material. At the same time, the graphene-styrene graft can combine with nylon 66 to form a three-dimensional aerogel structure, which has good dispersibility with nylon 12 and high mutual bonding strength, and the mechanical properties of the product are excellent.

[0022] The present invention uses graphene oxide in combination with styrene and maleic anhydride, and grafts them on the surface of graphene through free radical polymerization, which can greatly improve the interfacial compatibility between graphene oxide and nylon 66. After nylon 66 is dissolved and combined with the graphene-styrene graft, due to the rich carboxyl groups in the graphene-styrene graft, it can have a strong interaction with the amide groups of nylon 66, and the combination effect of the two is good. The pretreated nylon 66 formed by freezing treatment has a three-dimensional aerogel structure. When combined with nylon 12, when subjected to external force, it can effectively transfer the load, significantly improve the bending performance of the product, and at the same time has excellent impact performance. When subjected to external force, it will effectively undergo flexible deformation, and the toughening effect is excellent.

[0023] The present invention uses freeze setting to coat nylon 66 on the graphite oxide sheet layer structure. Even at low filling amounts, a stable flame retardant layer can be formed, better exerting the flame retardant effect of the carbon layer. At the same time, it can be evenly dispersed in the nylon resin matrix, greatly improving the mechanical properties of the product; and the regular graphite oxide sheet layer structure increases the carbon layer area after combustion, and cooperates with triphenyl phosphate to dehydrate and catalyze carbon formation, with a significant barrier effect and excellent fire prevention performance of the product.

[0024] Polyethylene can effectively improve the fluidity of nylon. In combination with the graphene-styrene graft, it effectively improves the compatibility between nylon and polyethylene, not only enhancing the toughness of the pipe body, but also improving the fluidity and melt compatibility of the system, and can smoothly extrude nylon pipes, and the products have good molding stability.

[0025] The present invention pretreats nylon 66 and then compounds it with nylon 12, polyethylene, polyethylene-maleic anhydride, triphenyl phosphate, etc. After molding, the oxygen index of the product can not only reach more than 38.6%, and the flame retardant grade can reach the V-0 grade of UL-94. At the same time, it has high mechanical strength and is not prone to brittle fracture during long-term use. Moreover, the process is simple, the reaction conditions are mild, and it is suitable for large-scale industrial production. Description of the Drawings

[0026] Figure 1 It is a comparison chart of the tensile strength and elongation at break of the quick-connect fitting materials of the nylon pipes obtained in Example 5 and Comparative Examples 1-2.

[0027] Figure 2 It is a comparison chart of the flexural strength and flexural modulus of the quick-connect fitting materials of the nylon pipes obtained in Example 5 and Comparative Examples 1-2.

[0028] Figure 3 It is the water absorption and Izod impact strength of the quick-connect fitting materials of the nylon pipes obtained in Example 5 and Comparative Examples 1-2

[0029] Figure 4 It is a comparison chart of the oxygen index of the quick-connect fitting materials of the nylon pipes obtained in Example 5 and Comparative Examples 1-2. Detailed Embodiments

[0030] The present invention will be further explained below in conjunction with specific embodiments.

[0031] The nylon 66 used below is from DuPont, USA, with the grade of 101L; the nylon 12 is from Evonik Degussa, Germany, with the grade of A1709P. Both the nylon 66 and nylon 12 used below need to be vacuum dried at 80 °C for 10 h before feeding.

[0032] Example 1

[0033] A high-stability nylon tube quick-connect fitting material, the raw materials of which include: 50 kg of nylon 12, 5 kg of nylon 66, 1 kg of graphene oxide, 5 kg of styrene, 2 kg of maleic anhydride, 0.1 kg of azobisisobutyronitrile, 5 kg of polyethylene, 1 kg of polyethylene-maleic anhydride, 1 kg of triphenyl phosphite, 1 kg of butyl stearate, 1 kg of aluminum hydroxide, and 1 kg of antioxidant 1010.

[0034] The preparation method of the above high-stability nylon tube quick-connect fitting material includes the following steps:

[0035] S1. Add graphene oxide and styrene to 50 kg of solvent, ultrasonically treat for 10 min, the ultrasonic frequency is 5 kHz, add maleic anhydride and azobisisobutyronitrile thereto, stir at 60 °C for 1 h, remove the solvent, wash once with acetone, and vacuum dry to obtain a graphene-styrene graft;

[0036] S2. Add nylon 66 to 40 kg of a 70% formic acid solution, stir at 60 °C for 1 h, add the graphene-styrene graft thereto, stir for 10 min, cool down to -50 °C, freeze for 1 h, and vacuum dry for 20 h, the vacuum degree is 10 Pa, to obtain pretreated nylon 66;

[0037] S3. Feed nylon 12 and pretreated nylon 66 into a twin-screw extruder for co-extrusion, granulation, and drying; add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, butyl stearate, aluminum hydroxide, and antioxidant 1010 into a single-screw extruder for melt extrusion, wherein the melting temperature is 200 °C, the screw speed is 50 r / min, draw forming, the draw ratio is 1.1, the vacuum of the sizing sleeve is evacuated to 10 kPa, and then cooled.

[0038] Example 2

[0039] A high-stability nylon tube quick-connect fitting material, the raw materials of which include: 100 kg of nylon 12, 10 kg of nylon 66, 3 kg of graphene oxide, 10 kg of styrene, 5 kg of maleic anhydride, 0.2 kg of azobisisobutyronitrile, 10 kg of polyethylene, 2 kg of polyethylene-maleic anhydride, 2 kg of triphenyl phosphite, 2 kg of ethylene bis-stearamide, 2 kg of polysiloxane, and 2 kg of antioxidant 168.

[0040] The preparation method of the above high-stability nylon tube quick-connect fitting material includes the following steps:

[0041] S1. Add graphene oxide and styrene to 80 kg of solvent, ultrasonically treat for 30 min, the ultrasonic frequency is 10 kHz, add maleic anhydride and azobisisobutyronitrile thereto, stir at 80 °C for 2 h, remove the solvent, wash with acetone 3 times, and vacuum dry to obtain a graphene-styrene graft;

[0042] S2. Add nylon 66 to 60 kg of a formic acid solution with a mass fraction of 80%, stir at 70 °C for 2 h, add the graphene-styrene graft thereto, stir for 30 min, cool to -80 °C, freeze for 2 h, and vacuum dry for 30 h, the vacuum degree is 50 Pa, to obtain pretreated nylon 66;

[0043] S3. Feed nylon 12 and pretreated nylon 66 into a twin-screw extruder for co-extrusion, granulation, and drying; add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, ethylene bis-stearamide, polysiloxane, and antioxidant 168 into a single-screw extruder for melt extrusion, wherein the melting temperature is 230 °C, the screw speed is 50 - 80 r / min, draw forming, the draw ratio is 1.2, the vacuum of the sizing sleeve is evacuated to 50 kPa, and then cool.

[0044] Example 3

[0045] A high-stability nylon tube quick-connect fitting material, the raw materials of which include: 75 kg of nylon 12, 9 kg of nylon 66, 1.5 kg of graphene oxide, 9 kg of styrene, 3 kg of maleic anhydride, 0.18 kg of azobisisobutyronitrile, 7 kg of polyethylene, 1.7 kg of polyethylene-maleic anhydride, 1.2 kg of triphenyl phosphite, 1.7 kg of liquid paraffin, 1.4 kg of glass microspheres, and 1.6 kg of antioxidant 1076.

[0046] The preparation method of the above high-stability nylon tube quick-connect fitting material includes the following steps:

[0047] S1. Add graphene oxide and styrene into 60 kg of solvent, and perform ultrasonic treatment for 25 min at an ultrasonic frequency of 6 kHz. Add maleic anhydride and azobisisobutyronitrile thereto, stir at 75 °C for 80 min, remove the solvent, wash with acetone three times, and perform vacuum drying to obtain a graphene-styrene graft;

[0048] S2. Add nylon 66 into 45 kg of formic acid solution with a mass fraction of 77%, stir at 62 °C for 100 min, add the graphene-styrene graft thereto, stir for 15 min, cool down to -70 °C, freeze for 80 min, and perform vacuum drying for 28 h at a vacuum degree of 20 Pa to obtain pretreated nylon 66;

[0049] S3. Feed nylon 12 and pretreated nylon 66 into a twin-screw extruder for coextrusion and granulation, and then dry. Add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, liquid paraffin, glass microspheres, and antioxidant 1076 into a single-screw extruder for melt extrusion, wherein the melting temperature is 220 °C, the screw speed is 60 r / min, perform traction molding with a draw ratio of 1.17, and after the sizing sleeve is evacuated to 20 kPa, cool down.

[0050] Example 4

[0051] A high-stability nylon tube quick-connect fitting material, the raw materials of which include: 95 kg of nylon 12, 7 kg of nylon 66, 2.5 kg of graphene oxide, 7 kg of styrene, 4 kg of maleic anhydride, 0.12 kg of azobisisobutyronitrile, 9 kg of polyethylene, 1.3 kg of polyethylene-maleic anhydride, 1.8 kg of triphenyl phosphite, 1.3 kg of polyethylene wax, 1.8 kg of glass microspheres, and 1.2 kg of antioxidant 168.

[0052] The preparation method of the above high-stability nylon tube quick-connect fitting material comprises the following steps:

[0053] S1. Add graphene oxide and styrene into 70 kg of solvent, and perform ultrasonic treatment for 15 min at an ultrasonic frequency of 9 kHz. Add maleic anhydride and azobisisobutyronitrile thereto, stir at 65 °C for 100 min, remove the solvent, wash with acetone once, and perform vacuum drying to obtain a graphene-styrene graft;

[0054] S2. Add nylon 66 into 55 kg of formic acid solution with a mass fraction of 73%, stir at 68 °C for 80 min, add the graphene-styrene graft thereto, stir for 25 min, cool down to -60 °C, freeze for 100 min, and perform vacuum drying for 22 h at a vacuum degree of 40 Pa to obtain pretreated nylon 66;

[0055] S3. Feed nylon 12 and pretreated nylon 66 into a twin-screw extruder for co-blending extrusion, granulation, and drying; add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, polyethylene wax, glass beads, and antioxidant 168 into a single-screw extruder for melting extrusion, where the melting temperature is 210 °C, the screw speed is 70 r / min, for traction molding, the draw ratio is 1.12, after the sizing sleeve is evacuated to 40 kPa, cool down.

[0056] Example 5

[0057] A highly stable nylon tube quick-connect fitting material, the raw materials of which include: 85 kg of nylon 12, 8 kg of nylon 66, 2 kg of graphene oxide, 8 kg of styrene, 3.5 kg of maleic anhydride, 0.15 kg of azodiisobutyronitrile, 8 kg of polyethylene, 1.5 kg of polyethylene-maleic anhydride, 1.5 kg of triphenyl phosphite, 1.5 kg of polypropylene wax, 1.6 kg of glass beads, and 1.4 kg of antioxidant 1010.

[0058] The preparation method of the above highly stable nylon tube quick-connect fitting material includes the following steps:

[0059] S1. Add graphene oxide and styrene into 65 kg of solvent for ultrasonic treatment for 20 min, the ultrasonic frequency is 7.5 kHz, add maleic anhydride and azodiisobutyronitrile into it, stir at 70 °C for 90 min, remove the solvent, wash with acetone twice, and vacuum dry to obtain a graphene-styrene graft;

[0060] S2. Add nylon 66 into 50 kg of formic acid solution with a mass fraction of 75%, stir at 65 °C for 90 min, add the graphene-styrene graft into it, stir for 20 min, cool down to -65 °C, freeze for 90 min, and vacuum dry for 25 h, the vacuum degree is 30 Pa, to obtain pretreated nylon 66;

[0061] S3. Feed nylon 12 and pretreated nylon 66 into a twin-screw extruder for co-blending extrusion, granulation, and drying; add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, polypropylene wax, glass beads, and antioxidant 1010 into a single-screw extruder for melting extrusion, where the melting temperature is 215 °C, the screw speed is 65 r / min, for traction molding, the draw ratio is 1.15, after the sizing sleeve is evacuated to 30 kPa, cool down.

[0062] Comparative Example 1

[0063] A high-stability nylon tube quick-connect fitting material, the raw materials of which include: 85 kg of nylon 12, 8 kg of nylon 66, 2 kg of graphene oxide, 8 kg of styrene, 3.5 kg of maleic anhydride, 0.15 kg of azobisisobutyronitrile, 8 kg of polyethylene, 1.5 kg of polyethylene-maleic anhydride, 1.5 kg of triphenyl phosphite, 1.5 kg of polypropylene wax, 1.6 kg of glass beads, and 1.4 kg of antioxidant 1010.

[0064] The preparation method of the above high-stability nylon tube quick-connect fitting material includes the following steps:

[0065] S1. Add graphene oxide and styrene to 65 kg of solvent, ultrasonically treat for 20 min, the ultrasonic frequency is 7.5 kHz, add maleic anhydride and azobisisobutyronitrile thereto, stir at 70 °C for 90 min, remove the solvent, wash twice with acetone, and vacuum dry to obtain a graphene-styrene graft;

[0066] S2. Feed nylon 12, nylon 66 and the graphene-styrene graft into a twin-screw extruder for co-extrusion and granulation, and dry; add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, polypropylene wax, glass beads, and antioxidant 1010 into a single-screw extruder for melt extrusion, wherein the melting temperature is 215 °C, the screw speed is 65 r / min, draw forming is carried out, the draw ratio is 1.15, the vacuum of the sizing sleeve is evacuated to 30 kPa, and cooling is carried out.

[0067] Comparative Example 2

[0068] A high-stability nylon tube quick-connect fitting material, the raw materials of which include: 85 kg of nylon 12, 8 kg of nylon 66, 2 kg of graphene oxide, 8 kg of polyethylene, 1.5 kg of polyethylene-maleic anhydride, 1.5 kg of triphenyl phosphite, 1.5 kg of polypropylene wax, 1.6 kg of glass beads, and 1.4 kg of antioxidant 1010.

[0069] The preparation method of the above high-stability nylon tube quick-connect fitting material includes the following steps:

[0070] S1. Add nylon 66 to 50 kg of formic acid solution with a mass fraction of 75%, stir at 65 °C for 90 min, add graphene thereto, stir for 20 min, cool down to -65 °C, freeze for 90 min, and vacuum dry for 25 h, the vacuum degree is 30 Pa, to obtain pretreated nylon 66;

[0071] S2. Feed nylon 12 and pretreated nylon 66 into a twin-screw extruder for coextrusion and granulation, and then dry them; add polyethylene, polyethylene-maleic anhydride, triphenyl phosphite, polypropylene wax, glass microspheres, and antioxidant 1010 into a single-screw extruder for melt extrusion, where the melting temperature is 215 °C, the screw speed is 65 r / min, draw forming is carried out, the draw ratio is 1.15, the vacuum of the sizing sleeve is pumped to 30 kPa, and then it is cooled.

[0072] Perform performance tests on the nylon tube quick-connect fitting materials obtained in Example 5 and Comparative Examples 1-2, as follows:

[0073] (1) Refer to GB / T 1040.2-2022 "Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and extrusion plastics" to determine the tensile strength and elongation at break of each group of specimens. The specimen size is 170 mm × 10 mm × 4 mm, the test rate is 50 mm / min, and the test temperature is room temperature.

[0074] (2) Refer to GB / T 9341-2008 "Plastics - Determination of flexural properties" to determine the flexural strength and flexural modulus of each group of specimens. The specimen size is 80 mm × 10 mm × 4 mm, the test rate is 2 mm / min, the deflection is 6 mm, the specimen support span is 64 mm, and the test temperature is room temperature.

[0075] (3) Refer to GB / T 1034-2008 "Plastics - Determination of water absorption" to determine the water absorption of each group of specimens.

[0076] (4) Refer to GB / T 1843-2008 "Plastics - Determination of Izod impact strength" to determine the impact strength of each group of specimens. Use Type A notch, the radius at the bottom of the notch is 0.25 ± 0.05 mm, the pendulum energy is 2.75 J, and the specimen size is 80 mm × 10 mm × 4 mm.

[0077] (5) Refer to GB / T 2406.1-2008 "Plastics - Determination of burning behaviour by the oxygen index - Part 1: Guidelines" to determine the oxygen index of each group of specimens.

[0078] As Figure 1 shown, the nylon tube quick-connect fitting material obtained in Example 5 has the highest tensile strength, which is better than that of Comparative Examples 1-2 (P < 0.05). Although the elongation at break of the nylon tube quick-connect fitting material obtained in Example 5, there is no significant difference compared with the other two groups (P > 0.05).

[0079] As Figure 2 shown, both the flexural strength and flexural modulus of the nylon tube quick-connect fitting material obtained in Example 5 are the highest, which is better than that of Comparative Examples 1-2 (P < 0.05).

[0080] As Figure 3 shown, the water absorption of the quick-insert joint material of the nylon tube obtained in Example 5 is the lowest, while the impact strength is the highest, both of which are better than those of Comparative Examples 1-2 (P < 0.05).

[0081] As Figure 4 shown, the oxygen index of the quick-insert joint material of the nylon tube obtained in Example 5 is the highest, which is better than those of Comparative Examples 1-2 (P < 0.05), indicating that the flame retardant performance of the quick-insert joint material of the nylon tube obtained in Example 5 is the best.

[0082] The applicant believes that: this is because by preparing graphene-styrene grafts in the present invention, the agglomeration phenomenon of graphene oxide can be effectively avoided, and the interfacial interaction between graphene oxide and the nylon matrix can be improved, enhancing the mechanical properties of the composite material. At the same time, the graphene-styrene grafts can combine with nylon 66 to form a three-dimensional aerogel structure, which has good dispersibility with nylon 12 and high binding strength between each other, and the mechanical properties of the product are excellent. In the present invention, graphene oxide is combined with styrene and maleic anhydride, and grafted on the surface of graphene through free radical polymerization, which can greatly improve the interfacial compatibility between graphene oxide and nylon 66. After nylon 66 is dissolved and combined with the graphene-styrene grafts, since the graphene-styrene grafts contain rich carboxyl groups, they have strong interaction with the amide groups of nylon 66, and the combination effect of the two is good. The pretreated nylon 66 formed by freezing treatment has a three-dimensional aerogel structure. When combined with nylon 12, when subjected to external force, the load can be effectively transferred, significantly improving the bending performance of the product, and at the same time, the impact performance is excellent. When subjected to external force, it will effectively undergo flexible deformation, and the toughening effect is excellent. In the present invention, nylon 66 is coated on the graphene oxide sheet layer structure by freeze setting, and a stable flame retardant layer can be formed even at a low filling amount, better exerting the flame retardant effect of the carbon layer, and at the same time, it can be evenly dispersed in the nylon resin matrix, greatly improving the mechanical properties of the product; and the regular graphene oxide sheet layer structure increases the area of the carbon layer after combustion, and cooperates with triphenyl phosphate to dehydrate and catalyze carbon formation, and the barrier effect is significant, and the fire prevention performance of the product is excellent.

[0083] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A high-stability quick-connect joint material for nylon pipes, characterized in that, Its raw materials by mass parts include: 50 - 100 parts of nylon 12, 5 - 10 parts of nylon 66, 1 - 3 parts of graphene oxide, 5 - 10 parts of styrene, 2 - 5 parts of maleic anhydride, 0.1 - 0.2 parts of initiator, 5 - 10 parts of polyethylene, 1 - 2 parts of polyethylene - maleic anhydride, 1 - 2 parts of triphenyl phosphite, 1 - 2 parts of lubricant, 1 - 2 parts of waterproofing agent, 1 - 2 parts of antioxidant; The waterproofing agent is at least one of aluminum hydroxide, polysiloxane, glass microspheres, calcium stearate; It is prepared by the following steps: S1. Add graphene oxide and styrene into a solvent and ultrasonically treat for 10 - 30 min. Add maleic anhydride and initiator thereto, stir at 60 - 80 °C for 1 - 2 h, remove the solvent, wash, and vacuum dry to obtain a graphene - styrene graft; S2. Add nylon 66 into a formic acid solution, stir at 60 - 70 °C for 1 - 2 h. Add the graphene - styrene graft thereto and stir for 10 - 30 min. Cool down to - 50 to - 80 °C, freeze for 1 - 2 h, and vacuum dry for 20 - 30 h with a vacuum degree of 10 - 50 Pa to obtain pretreated nylon 66; S3. Blend nylon 12 and pretreated nylon 66, extrude and pelletize, and dry. Then add polyethylene, polyethylene - maleic anhydride, triphenyl phosphite, lubricant, waterproofing agent, and antioxidant and melt - extrude, followed by drawing and forming.

2. The high-stability nylon tube quick-connect fitting material according to claim 1, wherein The initiator is azobisisobutyronitrile.

3. The high-stability nylon tube quick-connect fitting material according to claim 1, characterized in that, The lubricant is at least one of butyl stearate, ethylene bisstearamide, liquid paraffin, polyethylene wax, polypropylene wax.

4. The high-stability nylon tube quick-connect fitting material according to claim 1, characterized in that, The antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 1076.

5. A preparation method of the high-stability nylon tube quick-insertion joint material according to any one of claims 1-4, characterized in that, It includes the following steps: S1. Add graphene oxide and styrene into a solvent and ultrasonically treat for 10 - 30 min. Add maleic anhydride and initiator thereto, stir at 60 - 80 °C for 1 - 2 h, remove the solvent, wash, and vacuum dry to obtain a graphene - styrene graft; S2. Add nylon 66 into a formic acid solution, stir at 60 - 70 °C for 1 - 2 h. Add the graphene - styrene graft thereto and stir for 10 - 30 min. Cool down to - 50 to - 80 °C, freeze for 1 - 2 h, and vacuum dry for 20 - 30 h with a vacuum degree of 10 - 50 Pa to obtain pretreated nylon 66; S3. Blend nylon 12 and pretreated nylon 66, extrude and pelletize, and dry. Then add polyethylene, polyethylene - maleic anhydride, triphenyl phosphite, lubricant, waterproofing agent, and antioxidant and melt - extrude, followed by drawing and forming.

6. The preparation method of the high-stability nylon tube quick-connect fitting material according to claim 5, characterized in that, In S1, the ultrasonic frequency is 5 - 10 kHz.

7. The preparation method of the high-stability nylon tube quick-connect fitting material according to claim 5, characterized in that In S1, the solvent is toluene or xylene.

8. The preparation method of the high-stability nylon tube quick-connect fitting material according to claim 5, characterized in that, In S3, the melting temperature is 200 - 230 °C.

9. The preparation method of the highly stable nylon tube quick-connect joint material according to claim 5, characterized in that In S3, during the drawing and forming process, the draw ratio is 1.1 - 1.2, and the sizing sleeve is evacuated to 0.01 - 0.05 MPa.

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