Organic phosphine flame-retardant nylon composition having good wet electrical properties, and preparation method therefor and use thereof

Abstract

Disclosed in the present invention are an organic phosphine flame-retardant nylon composition having good wet electrical properties, and a preparation method therefor and the use thereof. The organic phosphine flame-retardant nylon composition comprises the following components in parts by weight: 23-53 parts of a short-chain aliphatic nylon resin, 10-15 parts of a long-chain aliphatic nylon resin, 5-10 parts of a semi-aromatic nylon resin, 20-30 parts of glass fibers, 10-16 parts of a hypophosphite, and 2-6 parts of an inorganic synergist, wherein the glass transition temperature of the semi-aromatic nylon resin is greater than or equal to 88°C, and the glass fibers are hydrolysis-resistant glass fibers. The organic phosphine flame-retardant nylon composition of the present invention can achieve the integration of high flame-retardant properties and high wet electrical properties, and also has high mechanical properties.

Description

An organophosphorus flame-retardant nylon composition with excellent wet electrical properties, its preparation method and application Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to an organophosphorus flame-retardant nylon composition with excellent wet electrical properties, its preparation method, and its application. Background Technology

[0002] Organophosphorus flame-retardant nylon possesses excellent flame retardant properties, mechanical properties, low smoke and halogen-free characteristics, and is environmentally friendly, making it widely used in electronics, new energy, and rail transportation. While nylon exhibits excellent electrical properties in a dry state, it readily absorbs water in wet environments, leading to a significant decrease in its electrical properties. Furthermore, the introduction of organophosphorus flame retardants further deteriorates the wet-state electrical properties of nylon.

[0003] In the new energy industry, materials are often required to retain excellent electrical properties after high-temperature and high-humidity treatment (85℃ and 85%RH treatment for 1008h). However, the low wet-state electrical properties of organophosphorus flame-retardant nylon severely limit its application in the new energy industry. Therefore, there is an urgent need to develop an organophosphorus flame-retardant nylon composition that can balance high flame retardancy and wet-state electrical properties while maintaining excellent mechanical properties to meet the application requirements of materials in the new energy industry. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes an organophosphorus flame-retardant nylon composition with excellent wet electrical properties, its preparation method, and its applications.

[0005] This invention provides an organophosphorus flame-retardant nylon composition, comprising, by weight, the following components: 23-53 parts of short-chain aliphatic nylon resin, such as 23, 25, 30, 35, 40, 45, 50, or 53 parts; 10-15 parts of long-chain aliphatic nylon resin, such as 10, 11, 12, 13, 14, or 15 parts; 5-10 parts of semi-aromatic nylon resin, such as 5, 6, 7, 8, 9, or 10 parts; 20-30 parts of glass fiber, such as 20, 22, 24, 26, 28, or 30 parts; 10-16 parts of hypophosphite, such as 10, 11, 12, 13, 14, 15, or 16 parts; and 2-6 parts of inorganic synergist, such as 2, 3, 4, 5, or 6 parts; wherein the nylon resin accounts for not less than 48% by weight in the composition.

[0006] The glass transition temperature of the semi-aromatic nylon resin is ≥88℃, preferably 90-130℃. The glass transition temperature is tested using a differential scanning calorimeter according to ISO 11357-3:2013. The inventors found that a glass transition temperature of ≥88℃ for the semi-aromatic nylon resin can promote the barrier effect of the nylon composition under high temperature and high humidity conditions, and at the same time promote char formation to further improve the flame retardant performance.

[0007] The glass fiber is a hydrolysis-resistant glass fiber, which can inhibit the hydrolysis of nylon molecular chains under high temperature and high humidity, thereby improving the wet electrical properties of the composition.

[0008] Using inorganic synergists as flame retardant synergists in the system of this invention has the advantages of good stability and the ability to inhibit the decomposition of nylon molecular chains.

[0009] This invention improves the wet electrical properties of organophosphorus flame-retardant nylon by synergistically reducing the water absorption rate and concentration of nylon molecular chains through the low hygroscopicity of long-chain aliphatic nylon resin and the barrier properties of semi-aromatic nylon resin. By limiting the content of semi-aromatic and long-chain aliphatic nylon resins, the wet electrical properties of the organophosphorus flame-retardant nylon composition are significantly improved while maintaining good flame retardant and mechanical properties. Furthermore, by specifically selecting the glass transition temperature of the semi-aromatic nylon resin, both wet electrical properties and flame retardant and mechanical properties are further enhanced, achieving a unified overall performance. Finally, by selecting hydrolysis-resistant glass fibers and flame retardant synergists, the hydrolysis of nylon molecular chains under high temperature and humidity conditions is reduced, thereby improving the wet electrical properties of organophosphorus flame-retardant nylon.

[0010] Furthermore, the short-chain aliphatic nylon resin is one or more of PA66, PA6, PA56, and PA66 / 6.

[0011] Further, the long-chain aliphatic nylon resin is one or more of PA610, PA612 or PA1010; the melting point of the long-chain aliphatic nylon resin is ≥200℃, preferably 200-230℃, and the melting point is tested using a differential scanning calorimeter according to ISO 11357-3:2011 standard.

[0012] Further, the semi-aromatic nylon resin is one or more of PA6T / 66, PA6I / 6T, or PA6T / M-5T, wherein the 6T content of PA6T / 66 is 54-65%.

[0013] Furthermore, the hydrolysis-resistant glass fiber is E glass fiber, preferably E glass fiber with a surface modified by a silane coupling agent.

[0014] Furthermore, the inorganic synergist is any one or more of boehmite or aluminum polyphosphite;

[0015] Furthermore, the nylon composition further includes 0.1-1 parts by weight of antioxidant and / or 0.1-1 parts by weight of lubricant, and may also include other additives.

[0016] Furthermore, the hypophosphite is one or more of aluminum hypophosphite, diethyl aluminum hypophosphite, and diisopropyl aluminum hypophosphite, preferably diethyl aluminum hypophosphite.

[0017] The present invention also provides a method for preparing the nylon composition, comprising the following steps:

[0018] Weigh each component according to the weight parts, put each component into a mixer and mix until uniform to obtain a premix, then put the obtained premix into a twin-screw extruder for melt mixing, and extrusion granulation to obtain the nylon composition;

[0019] The twin-screw extruder has a screw speed of 250-350 rpm, a length-to-diameter ratio of (40-48):1, and a barrel temperature of 200-290℃.

[0020] The present invention also provides the application of the nylon composition in high-voltage connectors and new energy batteries.

[0021] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0022] (1) The nylon composition provided by the present invention has excellent mechanical properties;

[0023] (2) The nylon composition provided by the present invention can maintain excellent wet electrical properties while taking into account high flame retardancy. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] Example

[0026] The present invention will be further illustrated below with reference to specific embodiments and comparative embodiments. The following specific embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments, and are not in particular limited to the types of raw materials used in the following specific embodiments.

[0027] I. The sources of raw materials for the examples and comparative examples are as follows:

[0028] Short-chain aliphatic nylon resin #1: PA66, grade PA66 EP-158, Huafeng Group;

[0029] Short-chain aliphatic nylon resin #2: PA6, grade PA6 HY-2800A, Haiyang Chemical Fiber Company;

[0030] Long-chain aliphatic nylon resin #1: PA612, grade PA612 A120, melting point 215℃, Shandong Guangyin New Material Co., Ltd.

[0031] Long-chain aliphatic nylon resin #2: PA610, grade PA610 F120, melting point 222℃, Shandong Guangyin New Material Co., Ltd.

[0032] Long-chain aliphatic nylon resin #3: PA1212, grade PA1212, melting point 184℃, Shandong Dongchen Ruisen New Material Technology Co., Ltd.

[0033] Semi-aromatic nylon resin #1: PA6I / 6T, grade TI1207, glass transition temperature 130℃, Shandong Guangyin New Material Co., Ltd.

[0034] Semi-aromatic nylon resin #2: PA6T / 66, 6T content is 55%, grade VicnyI 400PNC003, glass transition temperature 95℃, Zhuhai Wantong Special Engineering Plastics Co., Ltd.

[0035] Semi-aromatic nylon resin #3: PA6T / M-5T, grade PA6T / M-5T, glass transition temperature 135℃, DuPont, USA;

[0036] Semi-aromatic nylon resin #4: PA66 / 6T, 6T content is 25%, grade NPD-652, glass transition temperature 70℃, Invista Ltd.

[0037] Hypophosphite: Diethylaluminum hypophosphite, grade OP1230, Klein Ltd.;

[0038] Inorganic synergist #1: Boehmite, grade BG-613SO, Anhui Yishitong Materials Technology Co., Ltd.;

[0039] Inorganic synergist #2: Aluminum polyphosphite, grade PA2103, Shenzhen Ruishixing Technology Co., Ltd.;

[0040] Flame retardant synergist #3: melamine polyphosphate, brand name BUDIT 3141, purchased from Budenheim Iberica GmbH, Germany;

[0041] Glass fiber #1: E glass fiber, grade ECS10-3.0-568H, surface modifier is silane coupling agent, China Jushi Co., Ltd.;

[0042] Glass fiber #2: TLD glass fiber, grade TLD-CS10-3.0-T436S, surface modifier is silane coupling agent, Taishan Glass Fiber Co., Ltd.;

[0043] Antioxidant: Brand name RIANOX 1098; the same substance was used in parallel tests.

[0044] Lubricant: Brand A-C540A, the same substance was used in parallel tests.

[0045] The preparation method of the polyamide / polyolefin composite material in the embodiments and comparative examples of the present invention includes the following steps:

[0046] Weigh each component according to the weight parts, put each component into a mixer and mix until uniform to obtain a premix, then put the obtained premix into a twin-screw extruder for melt mixing, and extrusion granulation to obtain the nylon composition;

[0047] The twin-screw extruder has a screw speed of 250-350 rpm, a length-to-diameter ratio of (40-48):1, and a barrel temperature of 200-290℃.

[0048] II. Performance Testing Methods

[0049] (1) Flame retardant performance: The flame retardant performance of the sample strip was tested according to the relevant standards of UL 94-2015. The sample thickness was 0.8mm. The flame retardant rating is divided into V-0, V-1, V-2 and no rating (NR). Flame retardant performance is of great significance to electrical safety. The UL94 flame retardant rating needs to reach V-0 to meet the application requirements.

[0050] (2) Tensile strength: tested in accordance with ISO 527-2012;

[0051] (3) Wet electrical performance test: To test the insulation resistance, the square plate (sample size 100*100*1mm) was first treated under double 85 conditions (85℃ / 85%RH) for 1008h, left for 4h, wiped dry the surface moisture, and tested according to IEC 62631-3-3-2015. The test voltage was 1000V DC and the pressure application time was 1min.

[0052] Table 1. Technical solutions and effects of the embodiments (unit: parts by weight)

[0053] Table 2 Comparative Example Technical Solutions and Effects (Unit: Parts by Weight) Comparative Example 4

[0054] Examples 1-9 simultaneously introduced short-chain aliphatic nylon resin, long-chain aliphatic nylon resin, semi-aromatic nylon resin with a specific glass transition temperature, as well as specific flame retardant synergists and glass fibers. Through this formulation combination, the organophosphorus flame-retardant nylon composition achieved high flame retardancy, high wet-state electrical properties, and high mechanical properties. Specifically, the vertical burning performance of the nylon composition reached V-2 level or higher, essentially reaching V-0 level, and the tensile strength reached over 108 MPa, essentially reaching over 120 MPa. Furthermore, after treatment under high temperature and high humidity conditions, the insulation resistance of the composition remained above 23 GΩ, exhibiting excellent wet-state electrical properties, thus achieving a balance between high flame retardancy and wet-state electrical properties in the organophosphorus nylon composition.

[0055] Comparative Examples 1-7 were all compared with Example 3. Comparative Example 1 only added conventional short-chain aliphatic nylon resin, without compounding with long-chain aliphatic nylon resin or semi-aromatic nylon resin. Test data showed that conventional organophosphorus flame-retardant nylon resin had poor wet electrical properties. In Comparative Example 3, the amount of long-chain aliphatic nylon resin added was too small, failing to effectively reduce water absorption, resulting in a significant decrease in the wet electrical properties of the nylon composition. Similarly, the amount of semi-aromatic nylon resin added was too small, failing to effectively reduce water absorption rate and limit ion migration, resulting in poor flame retardant and wet electrical properties in the organophosphorus flame-retardant nylon composition. In Comparative Example 4, too much semi-aromatic nylon resin was added, leading to poor compatibility of the organophosphorus flame-retardant nylon composition and a decline in mechanical and wet electrical properties. Comparative Example 5 used semi-aromatic... The glass transition temperature of nylon resin is below 90℃, which prevents semi-aromatic nylon resin from providing effective barrier properties under high temperature and humidity conditions. Furthermore, its poor char-forming ability reduces the flame retardant and wet electrical properties of the nylon composition. Comparative Example 6 uses non-hydrolysis-resistant glass fiber, which fails to effectively inhibit the hydrolysis of nylon molecular chains under high temperature and humidity conditions, thus reducing the wet electrical properties of the organophosphorus flame-retardant nylon composition. Comparative Example 7 uses melamine phosphate as a flame retardant synergist. While it imparts good flame retardant and mechanical properties to the organophosphorus flame-retardant nylon composition, it severely deteriorates its wet electrical properties. This is because melamine polyphosphate has poor thermal stability and readily degrades to produce phosphoric acid, which further promotes the degradation of nylon molecular chains under high temperature and humidity conditions, resulting in poor wet electrical properties. None of the above comparative examples achieve a balance between high flame retardant performance and good wet electrical properties, as well as good mechanical properties.

[0056] Based on the test data for vertical burning performance, tensile strength, and insulation resistance in Tables 1 and 2, the organophosphorus flame-retardant nylon compositions prepared through Examples 1-9 have significant advantages over the comparative examples and can effectively meet the high standards required by customers and the market.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An organophosphorus flame-retardant nylon composition, comprising the following components in parts by weight: The glass transition temperature of the semi-aromatic nylon resin is ≥88℃; The glass fiber is a hydrolysis-resistant glass fiber.

2. The nylon composition according to claim 1, characterized in that, The short-chain aliphatic nylon resin is one or more of PA66, PA6, PA56, and PA66 / 6.

3. The nylon composition according to claim 1, characterized in that, The long-chain aliphatic nylon resin is one or more of PA610, PA612 or PA1010; Preferably, the long-chain aliphatic nylon resin has a melting point ≥200℃.

4. The nylon composition according to claim 1, characterized in that, The semi-aromatic nylon resin is one or more of PA6T / 66, PA6I / 6T, or PA6T / M-5T.

5. The nylon composition of claim 1, wherein, The hydrolysis-resistant glass fiber is E glass fiber, preferably E glass fiber that has been surface modified with a silane coupling agent.

6. The nylon composition of claim 1, wherein, The inorganic synergist is any one or more of boehmite or polyaluminum polyphosphite.

7. The nylon composition according to claim 1, characterized in that, The hypophosphite is one or more of aluminum hypophosphite, diethylaluminum hypophosphite, and diisopropylaluminum hypophosphite.

8. The nylon composition according to claim 1, characterized in that, The glass transition temperature of the semi-aromatic nylon resin is 90-130℃.

9. A method for preparing the nylon composition according to any one of claims 1-8, characterized in that, Includes the following steps: Weigh each component according to the weight parts, put each component into a mixer and mix until uniform to obtain a premix. Then, put the obtained premix into a twin-screw extruder for melt mixing and extrusion granulation to obtain the nylon composition.

10. The use of the nylon composition according to any one of claims 1-8 in high-voltage connectors and new energy batteries.

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