Nylon composite material as well as preparation method and application thereof

Abstract

The invention discloses a nylon composite material which comprises the following components in parts by weight: 60-80 parts of aliphatic nylon; 15 to 35 parts of an MCA flame retardant; 5 to 10 parts of polyethylene glycol; and 4-10 parts of polyether block amide. The MCA with the specific free cyanuric acid content is used for generating inert gas due to the instant high temperature generated by an electric arc in an IPT test, the electric arc can be quickly diffused outwards, meanwhile, polyether block amide serves as a charge dissipation agent, the electric arc energy can be reduced, and the electric arc can be guided to be quickly diffused; meanwhile, polyethylene glycol is introduced, so that the water absorption of the nylon composite material can be improved, electric arc diffusion is coordinated, and the IPT is further improved. Meanwhile, the nylon composite material disclosed by the invention has the flame retardance of 0.8 mm V-0.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to a nylon composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Polyamide resins have excellent comprehensive properties such as mechanical properties, barrier properties, heat resistance, wear resistance, and chemical corrosion resistance. Their composite materials are widely used in fields such as mechanical manufacturing, household appliances, power tools, electronic appliances, and transportation. Among their many application scenarios, the requirements for the flame retardancy and IPT performance of composite materials are getting higher and higher.

[0003] The nitrogen-based flame retardant melamine cyanurate (abbreviated as MCA) has the advantages of being green and environmentally friendly, low smoke density, excellent electrical properties, light density, easy coloring, and high cost performance. It is widely used in the flame retardant modification of nylon, and its modified products are widely used in connectors, low-voltage electrical appliances, contactors, ordinary electrical appliance housings, etc. The current technology mainly focuses on the flame retardant stability of MCA composite materials. For example, Chinese Patent CN 103408750 A adds melamine cyanurate (MCA) as a flame retardant, and nano-SiO2 and metal oxides as synergistic flame retardants during the polymerization of polyamide monomers to in-situ polymerize flame retardant polyamide. Although this method can prepare composite materials with excellent flame retardant stability and mechanical properties, it is not suitable for large-scale industrial production.

[0004] On the other hand, the research on improving the IPT of flame retardant nylon mainly focuses on non-nitrogen-based systems. For example, in CN114456593 B, an aromatic polyamide and an inorganic hydroxide scheme are used in an organic phosphine system to obtain high IPT performance; in CN114672160 B, an inorganic hydroxide and a toughening agent scheme are used in a red phosphorus system to obtain an IPT of 1.5 kV. However, in a halogen-free nitrogen-based flame retardant system, all these substances currently disclosed will seriously affect the flame retardant nylon of the composite material, causing it to directly change from V-0 to V-2 flame retardancy. Therefore, there is very little relevant work on how to obtain a halogen-free nitrogen-based flame retardant nylon composite material with high IPT and V0 flame retardancy. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical defects and provide a nylon composite material with nitrogen-based 0.8 mm V-0 flame retardancy and an IP greater than or equal to 2.5 kV, a preparation method thereof, and an application thereof.

[0006] The present invention is achieved through the following technical solutions: A nylon composite material, calculated by weight, includes the following components: 60-80 parts of aliphatic nylon; 15-35 parts of MCA flame retardant; 5-10 parts of polyethylene glycol; 4 - 10 parts of polyether block amide.

[0007] The number - average molecular weight range of the polyethylene glycol is 1000 - 4000.

[0008] Preferably, the number - average molecular weight range of the polyethylene glycol is 2000 - 3000.

[0009] The number - average molecular weight of polyethylene glycol can be measured by gel permeation chromatography - multi - angle laser light scattering method (SEC - MALLS) as follows: Weigh a certain amount of polyethylene glycol (accurate to 0.01 mg) and tetrahydrofuran (accurate to 0.1 mL), prepare a dilute polyethylene glycol solution, and after standing for 24 h, filter the sample solution through a semi - permeable membrane with a pore size of 0.45 μm and then inject it into the SEC - MALLS test system for measurement to obtain the corresponding data.

[0010] The free cyanuric acid content of the MCA flame retardant is 0.08 - 0.16 wt%, preferably 0.10 - 0.13 wt%.

[0011] The preparation method of the MCA flame retardant is as follows: The monomers melamine and cyanuric acid are added to a high - pressure reactor in a molar ratio of 1:1.03, using deionized water as the medium, controlling the reaction temperature at 105 °C, the reaction time at 2 h, and cooling to 30 °C for constant temperature. Filter the reactants by suction, then wash with deionized water and filter by suction again. Repeat this process many times, and then place the reactants in an oven at 100 °C to dry the moisture, thus obtaining the MCA flame retardant; Wash with deionized water at 80 °C repeatedly until the MCA flame retardant with the required free cyanuric acid is obtained.

[0012] The test method for the free cyanuric acid of the MCA flame retardant is: According to the industry standard HG / T 5341 - 2018, the gravimetric method is used for determination. Specifically: Take 10 g of the sample and add it to 100 mL of water, heat to boiling, and filter it by suction through a slow quantitative filter paper with three layers in a Buchner funnel while it is hot. Transfer the filtrate to a 150 mL beaker and heat it almost to boiling. While stirring continuously, add 10 mL of melamine solution (10 g / L), boil, let it stand at room temperature for 1 h, and then transfer it to cold water and let it stand for 10 mL. Then filter it by suction with a pre - weighed glass - sintered crucible and wash the precipitate with melamine solution (0.3 g / L). Transfer the glass - sintered crucible to an electro - thermal constant - temperature drying oven at 105 °C ± 2 °C and dry it for 2 hours, remove it, cool it, and weigh it. Calculate according to the following formula: W5 = (m1×0.5058 / m0)×100 = m1×50.58 / m0 m1 is the mass value of the precipitate, in g; m0 is the mass value of the sample, in g; 0.5058 is the coefficient for converting melamine cyanurate to cyanuric acid.

[0013] The aliphatic nylon is a polyamide obtained by polycondensing at least one aliphatic dicarboxylic acid with an aliphatic diamine or a cyclo-diamine; the aliphatic nylon is selected from one or more of PA6, PA66, PA610, PA612, and PA1212.

[0014] The relative viscosity range of the aliphatic nylon is measured to be 2.0 - 2.8 L / g according to the ISO 307 - 2007 standard.

[0015] The polyether block amide has a large number of ether bonds and amide bonds in its molecular structure, and it is extremely easy to form hydrogen bonds with water molecules in the air, greatly enhancing the water absorption of the material. On the other hand, due to the amide bond structure identical to that of nylon in the molecular structure, it has good compatibility with nylon resin without the need to add an additional compatibilizer.

[0016] The polyether block amide can be selected from the Pebax series of Arkema Chemical Co., Ltd. or the PELESTAT series of Sanyo Chemical Industries, Ltd. of Japan, etc.

[0017] Whether to add 0 - 2 parts of additives can be selected according to actual needs, and the additives are selected from at least one of antioxidants and lubricants.

[0018] The preparation method of the nylon composite material of the present invention includes the following steps: mixing each component evenly, and extruding and pelletizing through a twin-screw extruder to obtain the nylon composite material.

[0019] The application of the nylon composite material of the present invention is used for preparing high-voltage connectors and flame-retardant connectors.

[0020] The present invention has the following beneficial effects: In the present invention, MCA with a specific free cyanuric acid content generates inert gas due to the instantaneous high temperature generated by the arc in the IPT test, which is beneficial to quickly diffuse the arc outward. At the same time, the polyether block amide, as a charge dissipator, can reduce the arc energy and guide the arc to quickly diffuse; at the same time, introducing polyethylene glycol can enhance the water absorption of the nylon composite material and synergistically promote the arc diffusion, thereby further improving the IPT. At the same time, the nylon composite material of the present invention has a flame retardancy of 0.8mm V-0. Specific Embodiments

[0021] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0022] The raw materials used in the embodiments and comparative examples of the present invention are as follows Nylon 66: PA66 EP-158, Huafeng Group Co., Ltd.; Nylon 6: PA6 HY-2500A, Haiyang Technology Co., Ltd.; MCA-1: Free cyanuric acid content is 0.08 wt%, self-made; MCA-2: Free cyanuric acid content is 0.10 wt%, self-made; MCA-3: Free cyanuric acid content is 0.13 wt%, self-made; MCA-4: Free cyanuric acid content is 0.16 wt%, self-made; MCA-5: Free cyanuric acid content is 0.05 wt%, self-made; MCA-6: Free cyanuric acid content is 0.20 wt%, self-made; Polyethylene glycol-1, PEG-1000, number average molecular weight is 1000, manufacturer is Lotte Chemical Korea; Polyethylene glycol-2, PEG-1500, number average molecular weight is 1500, manufacturer is Lotte Chemical Korea; Polyethylene glycol-3, PEG-2000, number average molecular weight is 2000, manufacturer is Lotte Chemical Korea; Polyethylene glycol-4, PEG-3000, number average molecular weight is 3000, manufacturer is Lotte Chemical Korea; Polyethylene glycol-5, PEG-4000, number average molecular weight is 4000, manufacturer is Lotte Chemical Korea; Polyethylene glycol-6: PEG-800, number average molecular weight is 800, manufacturer is Lotte Chemical Korea; Polyethylene glycol-7: PEG-6000, number average molecular weight is 6000, manufacturer is Lotte Chemical Korea; Polyether block amide A: Pebax®2533 SD 01, Arkema Chemical Co., Ltd.; Polyether block amide B: Pebax®3533 SD 01, Arkema Chemical Co., Ltd.; Polyether block amide C: PELESTAT®300, Sanyo Chemical Industries, Ltd., Japan; Polyether block amide D: PELESTAT®2450, Sanyo Chemical Industries, Ltd., Japan; Antioxidant: N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine (IRGANOX1098), BASF; Lubricant: Ethylene bis stearamide, EBS HI-LUBE, Shinwon Korea.

[0023] Preparation methods of the example and comparative example nylon composites: Mix each component evenly, and extrude and pelletize through a twin-screw extruder to obtain nylon composites. The barrel temperature is set as follows: the temperature of the first zone is 80°C, the second zone is 180°C, the third zone is 270°C, the fourth zone is 270°C, the fifth zone is 250°C, the sixth zone is 250°C, the seventh zone is 250°C, the eighth zone is 250°C, the ninth zone is 250°C, the tenth zone is 260°C, and the main machine speed is 300 - 500 r / min.

[0024] Methods for each test: (1) IPT: Referring to ASTM D2303, place the specimen at a 45° inclination, install the conduit of the test liquid above the specimen and continuously add the liquid at a certain liquid flow rate. The two electrode materials are stainless steel, with a spacing of 50 mm. The high-voltage end is placed above the specimen, and the grounded end is placed below the specimen. The AC frequency is 48 - 62 Hz. Conduct the test under the specified voltage and liquid flow rate, and record the time taken for tracking breakdown to characterize the tracking resistance of the specimen. The test voltage is in the range of 1 - 5 kV. If the arc of the material does not exceed 25 mm within 1 h, it means that the IPT of the material passes this voltage.

[0025] (2) Flame retardant rating: Referring to the UL94 standard, the size of the test specimen is 125 mm * 13 mm * 0.8 mm.

[0026] Table 1: Weight parts of each component and test results of the nylon composites in Examples 1 - 7 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Nylon 66 60 70 80 70 70 70 Nylon 6 70 MCA-1 15 25 35 25 MCA-2 25 MCA-3 25 MCA-4 25 Polyethylene glycol-1 5 7 10 7 7 7 7 Polyether block amide A 4 7 10 7 7 7 7 Antioxidant 0.3 0.3 Lubricant 0.2 IPT, V 1500 1800 2000 1900 2000 2000 1900 Flame retardant grade V-0 V-0 V-0 V-0 V-0 V-0 V-0 It can be seen from Examples 2 / 5 - 7 that when MCA with a preferred cyanuric acid content is used, the IPT is higher.

[0027] Table 2: Weight parts of each component and test results of the nylon composites in Examples 8 - 14 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Nylon 66 70 70 70 70 70 70 70 MCA-1 25 25 25 25 25 25 25 Polyethylene glycol label -2 -3 -4 -5 -1 -1 -1 Polyethylene glycol content 7 7 7 7 7 7 7 Polyether block amide A 7 7 7 7 Polyether block amide B 7 Polyether block amide C 7 Polyether block amide D 7 IPT, V 1900 2200 2300 1800 1900 1800 1800 Flame retardant grade V-0 V-0 V-0 V-0 V-0 V-0 V-0 It can be seen from Examples 2 / 8 - 11 that when polyethylene glycol with a preferred number-average molecular weight is used, the IPT is higher.

[0028] Table 3: Weight parts of each component and test results of the comparative example nylon composites Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Nylon 66 70 70 70 70 70 70 70 70 MCA-1 25 25 25 25 25 25 MCA-5 25 MCA-6 25 Polyethylene glycol label -1 -1 -6 -7 / -1 -1 -1 Polyethylene glycol content 7 7 7 7 / 15 7 7 Polyether block amide A 7 7 7 7 7 7 0 15 IPT, V 1200 1000 1100 1800 900 1000 800 1500 Flame retardant grade V-0 V-0 V-2 V-2 V-0 V-2 V-0 V-2 It can be seen from Comparative Examples 1 / 2 that when the free cyanuric acid content of MCA is too low or too high, the IPT is very low.

[0029] It can be seen from Comparative Example 3 that when the number-average molecular weight of polyethylene glycol is too low, the IPT is low and it cannot reach V - 0.

[0030] It can be seen from Comparative Example 4 that when the number-average molecular weight of polyethylene glycol is too high, it cannot reach V - 0.

[0031] As can be seen from Comparative Example 5, the IPT is too low when polyethylene glycol is not contained.

[0032] As can be seen from Comparative Example 6, when the content of polyethylene glycol is too high, the IPT will be reduced instead, and the V-0 grade cannot be achieved.

[0033] As can be seen from Comparative Example 7, the IPT is low when polyether block amide is not contained.

[0034] As can be seen from Comparative Example 8, when the content of polyether block amide is too high, the V-0 grade cannot be achieved.

Claims

1. A nylon composite material, characterized in that: By weight, it includes the following components: Aliphatic nylon 60-80 parts; MCA flame retardant 15-35 parts; 5-10 parts of polyethylene glycol; Polyether block amide 4-10 parts.

2. The nylon composite material according to claim 1, characterized in that: The number average molecular weight of the polyethylene glycol is in the range of 1000-4000.

3. The nylon composite material according to claim 2, characterized in that: The number average molecular weight of the polyethylene glycol is in the range of 2000-3000.

4. The nylon composite material according to claim 1, characterized in that: The free cyanuric acid content of the MCA flame retardant is 0.08-0.16wt%, preferably 0.10-0.13wt%.

5. The nylon composite material according to claim 1, characterized in that: The aliphatic nylon is a polyamide obtained by polycondensing at least one aliphatic dicarboxylic acid with an aliphatic diamine or a cyclic diamine; the aliphatic nylon is selected from one or more of PA6, PA66, PA610, PA612, and PA1212.

6. The nylon composite material according to any one of claims 1 to 5, characterized in that: By weight, the invention further comprises 0-2 parts of auxiliary agents, wherein the auxiliary agents are selected from at least one of antioxidants and lubricants.

7. The method for preparing the nylon composite material according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: mixing the components uniformly, extruding and granulating through a twin-screw extruder, and obtaining a nylon composite material.

8. The use of the nylon composite material according to any one of claims 1 to 6, characterized in that: Used to prepare high voltage connectors and flame retardant connectors.