Fire-resistant flame-retardant nylon composition as well as preparation method and application thereof

Abstract

The invention discloses a fire-resistant and flame-retardant nylon composition as well as 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 a flame-retardant synergist and 1-4 parts of a carbon formation accelerator, the mass ratio of the hypophosphite to the flame retardant synergist is (2-4): 1; the relative viscosity of the aliphatic nylon resin is 2.6 to 2.9; the carbon forming accelerant is rare earth oxide or zinc stannate. The organic phosphine flame-retardant nylon composition disclosed by the invention has excellent flame retardant property and fire resistance and also has high mechanical property.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a fire-resistant and flame-retardant nylon composition, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of the new energy vehicle market, the market scale of new energy vehicle batteries is also continuously expanding. In recent years, the installed capacity of new energy vehicle batteries globally and in China has continued to grow, showing strong market demand. Organophosphorus flame-retardant nylon has excellent flame-retardant performance, mechanical properties, electrical properties, low smoke and halogen-free, and environmental protection advantages, and is widely used in new energy batteries, new energy electronic controls and other components. However, there is a risk of thermal runaway during the charging and discharging process of new energy batteries. Chinese standard GB 38031-2020 stipulates that the battery pack or system needs to withstand the fire resistance test, which means that the new energy vehicle industry has put forward higher requirements for the fire resistance performance of organophosphorus flame-retardant nylon applied in this field.

[0003] At present, to improve the fire resistance performance of flame-retardant nylon, mainly by introducing porcelain-forming fillers such as magnesium hydroxide, low-melting-point glass fiber and mica, adding ceramic minerals and fluxes to organophosphorus flame-retardant nylon to achieve that the material does not melt, drip or perforate after being burned for 5 minutes. However, the introduction of a large amount of fillers will cause a significant reduction in the mechanical properties (especially toughness) of organophosphorus flame-retardant nylon, which is also not conducive to the stable application of the material. Therefore, it is of great significance to develop a flame-retardant nylon material that can balance excellent mechanical properties and fire resistance performance. Summary of the Invention

[0004] Aiming at the defects in the prior art, the present invention provides a fire-resistant and flame-retardant nylon composition, a preparation method thereof, and an application thereof.

[0005] The present invention provides a flame-retardant nylon composition, which comprises the following components by weight: 28-60 parts of aliphatic nylon resin, such as 28, 30, 35, 40, 45, 50, 55, 58, 60 parts; 4-15 parts of semi-aromatic nylon resin, such as 4, 5, 8, 10, 12, 15 parts; 18-32 parts of glass fiber, such as 18, 20, 22, 24, 26, 28, 30, 32 parts; 12-21 parts of hypophosphite, such as 12, 14, 14.5, 15, 15.5, 16, 17, 18, 19, 21 parts; 3-9 parts of flame-retardant synergist, such as 3, 4, 5, 6, 7, 8, 9 parts; 1-4 parts of carbonization promoter, such as 1, 1.5, 2, 2.5, 3, 4 parts; adding aliphatic nylon resin and semi-aromatic nylon resin simultaneously can improve the flame-retardant performance and fire resistance performance of the composition. The semi-aromatic nylon in the system can synergistically promote the acceleration of carbonization speed and improve the quality of the carbon layer. The total amount of the nylon resin accounts for not less than 40% of the mass percentage of the nylon composition;

[0006] Among them, the mass ratio of the hypophosphite to the 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 the hypophosphite and the flame retardant synergist, it promotes carbon formation in the organophosphorus flame-retarded nylon composition, which helps to improve the flame retardancy and fire resistance of the composition simultaneously;

[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 the 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 fire process can be guaranteed, thus effectively providing fire resistance;

[0008] The carbon formation promoter is rare earth oxide or zinc stannate.

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

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

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

[0012] Furthermore, the rare earth oxide is any one of lanthanum oxide or cerium oxide. It is found in the present invention that adding rare earth oxide or zinc stannate to the organophosphorus flame-retarded nylon system can significantly improve the fire resistance of the organophosphorus flame-retarded nylon composition. The rare earth oxide or zinc stannate can accelerate the carbon formation rate and prevent the carbon layer from forming slowly and 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 a combination of aluminum hypophosphite, aluminum diethyl hypophosphite, or aluminum diisopropyl hypophosphite, preferably aluminum diethyl hypophosphite.

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

[0016] Further, the nylon composition further comprises 0.2-1 part by weight of antioxidant and / or 0.2-1 part 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 by parts by weight, put the components 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, wherein the ratio of the screw length to the diameter of the twin-screw extruder is (48-40):1, the barrel temperature is 200°C-280°C, and the screw speed is 250 rpm-350 rpm.

[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 retardancy and fire resistance.

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

[0023] In order to enable those skilled in the art to better understand the solution of 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 a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0024] Examples

[0025] The present invention will be further illustrated below with specific examples and comparative examples. The following specific examples are all preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the following examples, especially not limited to the models of the component raw materials used in the following specific examples.

[0026] I. The raw material sources of 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, Kubyshev Nitrogen (Shanghai) Engineering Plastics Co., Ltd.;

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

[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 Materials Co., Ltd.;

[0034] Glass fiber: E glass fiber, grade ECS10-3.0-568H, China National Building Material Company Limited;

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

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

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

[0038] Carbonization promoter #1: Lanthanum oxide, Zibo Rongruida Powder Material Factory;

[0039] Carbonization promoter #2: Cerium oxide, Zibo Rongruida Powder Material Factory;

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

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

[0042] Weigh each component by weight, put the components 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, where the length-diameter ratio of the screw of the twin-screw extruder is (48-40):1, the barrel temperature is 200°C - 280°C, and the screw speed is 250 rpm - 350 rpm.

[0043] II. Test Methods for Various Properties

[0044] (1) Flame Retardancy Test: The flame retardancy of the spline was tested according to the relevant standards of UL 94-2015. The thickness of the sample was 0.8 mm, and the flame retardant grades were V-0, V-1, V-2, and no grade (NR). Flame retardancy is of great significance for electrical safety. The UL94 flame retardant grade needs to reach V-0 to meet the application requirements.

[0045] (2) Tensile Strength Test: The test was carried out in accordance with ISO 527-2012.

[0046] (3) Izod Notched Impact Strength Test: The test was carried out in accordance with ISO 180-2000.

[0047] (4) Fire Resistance Test: The height of the methane blowtorch flame was 125 mm, the height of the inner flame was 40 mm, the flame temperature was 1000 °C, the blowtorch angle was 20 ± 5°, the inner flame was in contact with the square plate, the combustion time was 10 min, and the size of the spline was 100*100*2 mm. The evaluation was based on the appearance after combustion: Grade 1, the structure was intact; Grade 2, the structure was deformed; Grade 3, burned through or melted.

[0048] Table 1 Technical Solutions and Effects of Examples (in parts by weight)

[0049]

[0050] Table 2 Technical Solutions and Effects of Comparative Examples (in parts by weight)

[0051]

[0052] In Examples 1-11, an aliphatic nylon resin with a specific relative viscosity, a semi-aromatic resin, and rare earth oxides were simultaneously introduced. By controlling the mass ratio of hypophosphite and flame retardant synergist, the flame retardancy and fire resistance of the nylon composition were improved together, while ensuring that the mechanical properties of the composition were not affected. The nylon compositions prepared could all reach the V-0 flame retardant grade, and the fire resistance reached Grade 1. At the same time, the tensile strength was above 120 MPa, and the Izod notched impact strength reached above 9.5 MPa.

[0053] It can be seen from Example 3, Comparative Example 4, and Comparative Example 5 that the mass ratio between aluminum diethylphosphinate and aluminum phosphite has an important influence on the flame retardancy and fire resistance of the organophosphorus flame-retarded 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 be significantly reduced; it can be seen from Example 3, Comparative Example 1, and Comparative Example 3 that the lack of introduction of semi-aromatic nylon resin will result in poor flame retardancy and fire resistance of the organophosphorus flame-retarded nylon composition, but too high an addition amount of semi-aromatic nylon resin will lead to a significant reduction in the toughness of the material; it can be seen from Example 3, Comparative Example 2, and Comparative Example 8 that when the content of the carbonization promoter is low, the fire resistance of the organophosphorus flame-retarded nylon resin will be significantly reduced, and when the content of the carbonization promoter is high, the mechanical properties (especially toughness) will be greatly reduced; it can be seen from Example 3, Comparative Example 6, and Comparative Example 7 that too large or too small relative viscosity of PA66 will affect the fire resistance of the organophosphorus flame-retarded nylon composition. None of the above comparative examples can achieve good flame retardancy and fire resistance while realizing high mechanical properties of the composition.

[0054] Based on the test data of vertical burning performance, tensile strength, Izod notch impact strength, and fire resistance in Table 1 and Table 2, the organophosphorus flame-retarded nylon compositions prepared by Examples 1-11 have obvious advantages compared with the comparative examples and can effectively meet the high standards of customers and the market.

[0055] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nylon composition, characterized in that, By weight, it includes the following components: Wherein, the mass ratio of the hypophosphite to the flame retardant synergist is (2-4):1; The relative viscosity of the aliphatic nylon resin is 2.6-2.9; The carbon formation accelerator is rare earth oxide or zinc stannate.

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

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

1.

4. The nylon composition according to claim 1, wherein The semi-aromatic nylon resin is any one or more of PA MXD6, PA6I / 6T or PA MXD10.

5. The nylon composition according to claim 1, characterized in that, The rare earth oxide is any one of lanthanum oxide or cerium oxide.

6. The nylon composition according to claim 1, 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.

7. The nylon composition according to claim 1, characterized in that, The hypophosphite is one or a combination of aluminum hypophosphite, diethyl aluminum hypophosphite, and diisopropyl aluminum hypophosphite.

8. The nylon composition according to claim 1, characterized in that, The flame retardant synergist is any one or more of phosphite or polyaluminium phosphite.

9. A method for preparing the nylon composition according to any one of claims 1-8, characterized in that, The steps include: The components are weighed in parts by weight, and the components are put into a mixer to be mixed until uniform to obtain a premix, and then the obtained premix is put into a twin-screw extruder for melt mixing, and extrusion granulation is performed to obtain the nylon composition.

10. Use of the nylon composition according to any one of claims 1 to 8 in new energy batteries.

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