A flame resistant nylon composition, and methods of making and using the same

Abstract

The application discloses a fire-resistant and burn-resistant nylon composition and a preparation method and application thereof. The nylon composition comprises the following components in parts by weight: 28-60 parts of aliphatic nylon resin, 4-15 parts of semi-aromatic nylon resin, 18-32 parts of glass fiber, 12-21 parts of hypophosphite, 3-9 parts of flame-retardant synergist, and 1-4 parts of carbonation promoter, wherein a mass ratio of the hypophosphite to the flame-retardant synergist is (2-4) to 1; a relative viscosity of the aliphatic nylon resin is 2.6-2.9; and the carbonation promoter is rare earth oxide or zinc stannate. The organic phosphorus flame-retardant nylon composition has excellent flame-retardant performance and fire-resistant performance, and can also have high mechanical performance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to fire-resistant and flame-retardant nylon compositions, their preparation methods, and applications. Background Technology

[0002] With the rapid development of the new energy vehicle market, the market size of new energy vehicle batteries is also expanding continuously. In recent years, the installed capacity of new energy vehicle batteries globally and in China has continued to grow, demonstrating strong market demand. Organophosphorus flame-retardant nylon has excellent flame-retardant properties, mechanical properties, electrical properties, low smoke and halogen-free characteristics, and is environmentally friendly, and is widely used in new energy batteries and new energy electronic control components. However, new energy batteries are subject to the risk of thermal runaway during charging and discharging. The Chinese standard GB 38031-2020 stipulates that battery packs or systems must withstand fire resistance tests, which means that the new energy vehicle industry has placed higher requirements on the fire resistance performance of organophosphorus flame-retardant nylon used in this field.

[0003] Currently, improving the fire resistance of flame-retardant nylon mainly involves introducing ceramic fillers, such as magnesium hydroxide, low-melting-point glass fiber, and mica. This is achieved by adding ceramic minerals and fluxes to organophosphorus flame-retardant nylon to prevent melting, dripping, or perforation after 5 minutes of burning. However, the introduction of large amounts of fillers leads to a significant reduction in the mechanical properties (especially toughness) of organophosphorus flame-retardant nylon, which is also detrimental to the stable application of the material. Therefore, developing a flame-retardant nylon material that can balance excellent mechanical properties and fire resistance is of great significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a fire-resistant and flame-retardant nylon composition, its preparation method, and its applications.

[0005] This invention provides a flame-retardant nylon composition, comprising, by weight, the following components: 28-60 parts of aliphatic nylon resin, such as 28, 30, 35, 40, 45, 50, 55, 58, or 60 parts; 4-15 parts of semi-aromatic nylon resin, such as 4, 5, 8, 10, 12, or 15 parts; 18-32 parts of glass fiber, such as 18, 20, 22, 24, 26, 28, 30, or 32 parts; and 12-21 parts of hypophosphite, such as 12, 14, 14.5, 15, 15.5, or 1 part. 6, 17, 18, 19, 21 parts; flame retardant synergist 3-9 parts, such as 3, 4, 5, 6, 7, 8, 9 parts; charring accelerator 1-4 parts, such as 1, 1.5, 2, 2.5, 3, 4 parts; by simultaneously adding aliphatic nylon resin and semi-aromatic nylon resin, the flame retardant properties and fire resistance of the composition can be improved. Semi-aromatic nylon can synergistically promote the acceleration of charring rate and improve the quality of char layer in the system. The total amount of nylon resin accounts for not less than 40% of the mass percentage of the nylon composition.

[0006] The mass ratio of hypophosphite to flame retardant synergist is (2-4):1, such as 2:1, 2.5:1, 3:1, 3.5:1, 4:1; through the synergistic effect of hypophosphite and flame retardant synergist, the carbonization of organophosphine flame retardant nylon composition is promoted, which helps to improve the flame retardant properties and fire resistance of the composition at the same time.

[0007] The relative viscosity of the aliphatic nylon resin is 2.6-2.9, preferably 2.66-2.8, such as 2.66, 2.68, 2.7, 2.75, 2.77, 2.8. The relative viscosity is tested according to ISO 307-2007 standard (25°C, 96% concentrated sulfuric acid). By controlling the relative viscosity of the aliphatic nylon resin within a specific range, the melt strength during the burning process can be guaranteed, thereby effectively providing fire resistance.

[0008] The carbonization promoter is a rare earth oxide or zinc stannate.

[0009] Furthermore, the aliphatic nylon resin is any one or more of PA66, PA6, PA66 / 6, PA612, or PA56.

[0010] Furthermore, the aliphatic nylon resin is a blend of PA66 and PA6 resins in a mass ratio of (1-2):1.

[0011] Furthermore, the semi-aromatic nylon resin is any one or more of PA MXD6, PA6I / 6T or PA MXD10, preferably PA MXD6 resin.

[0012] Furthermore, the rare earth oxide is either lanthanum oxide or cerium oxide. The present invention has found that adding rare earth oxides or zinc stannate to the organophosphorus flame-retardant nylon system can significantly improve the fire resistance of the organophosphorus flame-retardant nylon composition. Rare earth oxides or zinc stannate can accelerate the carbonization rate and prevent the slow formation of the carbon layer from causing depressions.

[0013] Furthermore, the glass fiber is any one of E glass fiber, H glass fiber, S glass fiber, D glass fiber or C glass fiber, preferably E glass fiber.

[0014] Furthermore, the hypophosphite is one or more of aluminum hypophosphite, diethyl aluminum hypophosphite, and diisopropyl aluminum hypophosphite, preferably diethyl aluminum hypophosphite.

[0015] Furthermore, the flame retardant synergist is any one or more of phosphite or aluminum polyphosphate, preferably aluminum phosphite.

[0016] Furthermore, the nylon composition further includes 0.2-1 parts by weight of antioxidant and / or 0.2-1 parts by weight of lubricant.

[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. The twin-screw extruder has a screw length-to-diameter ratio of (48-40):1, a barrel temperature of 200℃-280℃, and a screw speed of 250rpm-350rpm.

[0019] The present invention also provides the application of the nylon composition in new energy batteries, especially in the preparation of battery end plates, battery brackets and battery lower shells.

[0020] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0021] (1) The nylon composition provided by the present invention has excellent flame retardant properties and fire resistance;

[0022] (2) The nylon composition provided by the present invention has excellent mechanical properties while taking into account fire resistance. Detailed Implementation

[0023] 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.

[0024] Example

[0025] 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.

[0026] I. The sources of raw materials for the examples and comparative examples are as follows:

[0027] Aliphatic nylon resin #1: PA66, grade PA66 EP-158, relative viscosity 2.68, Huafeng Group;

[0028] Aliphatic nylon resin #2: PA6, grade PA6 VOLGAMID27, relative viscosity 2.7, Kuibyshev Nitrogen (Shanghai) Engineering Plastics Co., Ltd.;

[0029] Aliphatic nylon resin #3: PA6, grade PA6 HY-2800, relative viscosity 2.8, Haiyang Chemical Fiber Company;

[0030] Aliphatic nylon resin #4: PA66, grade PA66 EPR24, relative viscosity 2.4, China Shenma Group Co., Ltd.;

[0031] Aliphatic nylon resin #5: PA66, grade PA66 EPR32, relative viscosity 3.04, China Shenma Group Co., Ltd.;

[0032] Semi-aromatic nylon resin #1: PA MXD6, grade MXD6 AP 250, Shanghai Yinggu Co., Ltd.;

[0033] Semi-aromatic nylon resin #2: PA6I / 6T, grade TI1207, Shandong Guangyin New Material Co., Ltd.;

[0034] Glass fiber: E glass fiber, grade ECS10-3.0-568H, China Jushi Co., Ltd.;

[0035] Hypophosphite: Diethylaluminum hypophosphite, grade OP1230, Clariant Ltd.;

[0036] Flame retardant synergist #1: Aluminum phosphite, Kingfa Securities;

[0037] Flame retardant synergist #2: Aluminum polyphosphite, Ruishixing Co., Ltd.;

[0038] Carbonization accelerator #1: Lanthanum oxide, Zibo Rongruida Powder Materials Factory;

[0039] Carbonization accelerator #2: Cerium oxide, Zibo Rongruida Powder Materials Factory;

[0040] Carbonization accelerator #3: Zinc stannate, Shanghai Xintema Chemical Co., Ltd.

[0041] The preparation method of the flame-retardant nylon composition in the embodiments and comparative examples of the present invention includes the following steps:

[0042] 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. The twin-screw extruder has a screw length-to-diameter ratio of (48-40):1, a barrel temperature of 200℃-280℃, and a screw speed of 250rpm-350rpm.

[0043] II. Performance Testing Methods

[0044] (1) Flame retardant performance test: The flame retardant performance of the sample strip was tested according to the relevant standard of UL 94-2015. The sample thickness was 0.8mm. The flame retardant rating was 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.

[0045] (2) Tensile strength test: The test shall be conducted in accordance with ISO 527-2012.

[0046] (3) Cantilever beam notched impact strength test: The test shall be conducted in accordance with ISO 180-2000.

[0047] (4) Fire resistance test: Methane torch flame height 125mm, inner flame height 40mm, flame temperature 1000℃, torch angle 20±5°, inner flame in contact with square plate, burning time 10min, sample size 100*100*2mm, evaluation based on appearance after burning: Level 1: structural integrity; Level 2: structural deformation; Level 3: burn-through or melting.

[0048] Table 1. Technical solutions and effects of the embodiments (unit: parts by weight)

[0049]

[0050] Table 2 Comparative examples of technical solutions and effects (unit: parts by weight)

[0051]

[0052] Examples 1-11 simultaneously introduced aliphatic nylon resin, semi-aromatic resin, and rare earth oxides with specific relative viscosities. By controlling the mass ratio of hypophosphite and flame retardant synergist, the flame retardant and fire resistance properties of the nylon composition were improved, while ensuring that the mechanical properties of the composition were not affected. The obtained nylon compositions all achieved a flame retardant rating of V-0 and a fire resistance rating of 1. The tensile strength was above 120 MPa, and the cantilever beam notched impact strength was above 9.5 MPa.

[0053] As shown in Examples 3 and Comparative Examples 4 and 5, the mass ratio between aluminum diethylphosphite and aluminum phosphite has a significant impact on the flame retardant and fire resistance properties of the organophosphine flame-retardant nylon composition. When the mass ratio between the two is not within the range of (2-4):1, the fire resistance of the composition will decrease significantly. As shown in Examples 3, Comparative Examples 1 and 3, the absence of semi-aromatic nylon resin results in poor flame retardant and fire resistance properties of the organophosphine flame-retardant nylon composition, but excessive addition of semi-aromatic nylon resin will lead to a significant decrease in material toughness. As shown in Examples 3, Comparative Examples 2 and 8, a low content of char-forming accelerator will significantly reduce the fire resistance of the organophosphine flame-retardant nylon resin, while a high content of char-forming accelerator will lead to a significant decrease in mechanical properties (especially toughness). As shown in Examples 3, Comparative Examples 6 and 7, both excessively high and low relative viscosity of PA66 will affect the fire resistance of the organophosphine flame-retardant nylon composition. None of the above comparative examples can simultaneously achieve good flame retardant properties, fire resistance properties, and high mechanical properties of the composition.

[0054] Based on the test data in Tables 1 and 2 regarding vertical burning performance, tensile strength, cantilever notched impact strength, and fire resistance, the organophosphorus flame-retardant nylon compositions prepared in Examples 1-11 have significant advantages over the comparative examples and can effectively meet the high standards required by customers and the market.

[0055] 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. A nylon composition, characterized in that, By weight, it includes the following components: 28-60 parts aliphatic nylon resin 4-15 parts of semi-aromatic nylon resin 18-32 parts glass fiber 12-21 parts hypophosphite 3-9 parts flame retardant synergist 1-4 parts of carbonization accelerator The mass ratio of hypophosphite to flame retardant synergist is (2-4):1; The relative viscosity of the aliphatic nylon resin is 2.6-2.8, and it was tested according to ISO 307-2007 standard under the following conditions: 25°C and 96% concentrated sulfuric acid. The carbonization promoter is a rare earth oxide; The semi-aromatic nylon resin is any one or more of PA MXD6, PA6I / 6T or PA MXD10; The rare earth oxide is either lanthanum oxide or cerium oxide; The hypophosphite is one or more of diethylaluminum hypophosphite and diisopropylaluminum hypophosphite; The flame retardant synergist is a phosphite.

2. A nylon composition, characterized in that, By weight, it includes the following components: 28-60 parts aliphatic nylon resin 4-15 parts of semi-aromatic nylon resin 18-32 parts glass fiber 12-21 parts hypophosphite 3-9 parts flame retardant synergist 1-4 parts of carbonization accelerator The mass ratio of hypophosphite to flame retardant synergist is (2-4):1; The relative viscosity of the aliphatic nylon resin is 2.6-2.8, and it was tested according to ISO 307-2007 standard under the following conditions: 25°C and 96% concentrated sulfuric acid. The carbonization promoter is a rare earth oxide; The semi-aromatic nylon resin is any one or more of PA MXD6, PA6I / 6T or PA MXD10; The rare earth oxide is either lanthanum oxide or cerium oxide; The hypophosphite is one or more of diethylaluminum hypophosphite and diisopropylaluminum hypophosphite; The flame retardant synergist is aluminum polyphosphite.

3. The nylon composition according to any one of claims 1-2, characterized in that, The aliphatic nylon resin is any one or more of PA66, PA6, PA66 / 6, PA612 or PA56.

4. The nylon composition according to claim 3, characterized in that, The aliphatic nylon resin is a blend of PA66 and PA6 resins in a mass ratio of (1-2):

1.

5. The nylon composition according to any one of claims 1-2, characterized in that, The glass fiber is any one of E glass fiber, H glass fiber, S glass fiber, D glass fiber or C glass fiber.

6. A method for preparing the nylon composition according to any one of claims 1-2, 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.

7. The use of the nylon composition according to any one of claims 1-2 in new energy batteries.

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