An organic phosphine flame-retardant nylon composition, its preparation method and application

Abstract

This invention discloses an organophosphorus flame-retardant nylon composition, its preparation method, and its application. The organophosphorus flame-retardant nylon composition, by weight, comprises the following components: 25-62 parts homopolymer nylon resin, 5-10 parts copolymer nylon resin, 5-15 parts barrier nylon resin, 20-30 parts glass fiber, 8-12 parts organophosphorus flame retardant, 1-4 parts flame retardant synergist, and 1-3 parts interface binder. The organophosphorus flame-retardant nylon composition of this invention exhibits excellent silicone adhesive properties, as well as high mechanical properties and flame-retardant properties.

Description

Technical Field

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

[0002] Organophosphorus flame-retardant nylon possesses excellent flame-retardant properties, mechanical properties, electrical properties, low smoke and halogen-free characteristics, and is environmentally friendly, making it widely used in electronics, new energy, and rail transportation. Silicone rubber, on the other hand, is highly regarded for its excellent high-temperature resistance, low-temperature resistance, electrical insulation, and flexibility in sealing, insulation, and protection applications. Bonding organophosphorus flame-retardant nylon to silicone rubber can achieve complementary and synergistic performance enhancements, such as solving the airtightness issues of new energy connectors and the connection problems of split liquid cooling pipes, bringing more innovation and convenience to product design and manufacturing.

[0003] Polyamide molecules are highly polar, while silicone rubber molecules are less polar, making it difficult for silicone rubber to form effective physical or chemical adhesion to nylon surfaces. Existing technologies often improve the adhesion between silicone rubber and polyamide substrates through plasma treatment followed by the application of a primer. The primer can simultaneously form chemical bonds with both silicone and polyamide surfaces, thus achieving the goal of silicone bonding to polyamide. However, the inventors discovered that when using a primer, the bond strength between conventional organophosphorus flame-retardant nylon compositions and silicone decreases over time. Further research revealed that this is because the organophosphorus flame retardant gradually migrates to the surface over time, causing a decrease in adhesion between silicone rubber and nylon during long-term storage. This results in low production efficiency and environmental pollution, severely limiting the application of this approach. Therefore, there is an urgent need to develop an organophosphorus flame-retardant nylon composition with excellent silicone rubber bonding properties and superior mechanical properties to improve production efficiency while avoiding the environmental pollution problems caused by primer use. Summary of the Invention

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

[0005] This invention provides an organophosphorus flame-retardant nylon composition, comprising, by weight, the following components: 25-62 parts of homopolymer nylon resin, such as 25, 26, 30, 35, 40, 45, 50, 55, 60, or 62 parts; 5-10 parts of copolymer nylon resin, such as 5, 6, 7, 8, 9, or 10 parts; 5-15 parts of barrier nylon resin, such as 5, 8, 10, 12, or 15 parts; and 20-30 parts of glass fiber, such as 20, 22, 24, or 2... 6, 28, 30 parts; 8-12 parts of organophosphorus flame retardant, such as 8, 9, 10, 11, 12 parts; 1-4 parts of flame retardant synergist, such as 1, 2, 3, 4 parts; 1-3 parts of interfacial binder, such as 1, 2, 3 parts; wherein the interfacial binder is one or more of siloxanes containing amino functional groups or siloxanes containing epoxy functional groups, and the flame retardant synergist is polyvinylpyrrolidone with a molecular weight of 1000-60000 g / mol;

[0006] In the formulation of this invention, the addition of barrier nylon can, on the one hand, reduce the migration of organophosphorus flame retardants to the surface and improve the adhesion between nylon and silicone. On the other hand, due to its benzene ring structure, it can promote char formation, thereby improving its flame retardant properties. Copolymer nylon is beneficial for improving the appearance of injection molding and reducing fiber floating, which can improve the adhesion of silicone rubber. The specific flame retardant synergist polyvinylpyrrolidone can combine with organophosphorus flame retardants, promote the dispersion of organophosphorus flame retardants, and inhibit their migration to the surface. While synergistically retardant, it can also improve the adhesion of silicone. In the specific interface binder, amino and epoxy groups can interact with the end groups of nylon, while alkoxy groups can interact with flame retardants or silicone rubber, thus improving the adhesion strength between the composition and silicone.

[0007] Furthermore, the homopolymer nylon resin is an aliphatic homopolymer nylon resin, preferably one or more of PA66, PA6, PA56, PA612 or PA610.

[0008] Furthermore, the copolynylon resin contains hexamethylenediamine adipate segments, preferably one or more of PA66 / 6, PA6 / 66, or PA66 / 6T.

[0009] Furthermore, the barrier nylon resin is one or more of PA MXD6, PA6I / 6T, or PA MXD10.

[0010] Furthermore, the organophosphorus flame retardant is one or more of aluminum hypophosphite, diethyl aluminum hypophosphite, and diisopropyl aluminum hypophosphite, preferably diethyl aluminum hypophosphite.

[0011] 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.

[0012] Furthermore, the interface binder is any one of aminomethoxysilane, aminoethoxysilane, epoxymethoxysilane, and epoxyethoxysilane.

[0013] Furthermore, the siloxanes containing amino functional groups include, but are not limited to, any one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-n-butyl-3-aminopropyltrimethoxysilane; and the siloxanes containing epoxy functional groups include, but are not limited to, any one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane.

[0014] The present invention also provides a method for preparing the nylon composition, comprising the following steps:

[0015] 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;

[0016] 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℃.

[0017] The present invention also provides the application of the nylon composition in new energy batteries, connectors and power tools.

[0018] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0019] (1) The organophosphorus flame-retardant nylon composition provided by the present invention has high bonding strength with silicone rubber;

[0020] (2) The organophosphorus flame-retardant nylon composition provided by the present invention can maintain high mechanical properties while improving the bonding strength with silicone rubber;

[0021] (3) The organophosphorus flame-retardant nylon composition provided by the present invention also has excellent flame-retardant properties. Detailed Implementation

[0022] 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.

[0023] Example

[0024] 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.

[0025] I. The sources of raw materials for the examples and comparative examples are as follows:

[0026] Homopolymer Nylon Resin #1: PA66, Grade PA66EP-158, Huafeng Group;

[0027] Homopolymer nylon resin #2: PA6, grade PA6HY-2800, Haiyang Chemical Fiber Company;

[0028] Homopolymer Nylon Resin #3: PA612, Grade PA612A120, Shandong Guangyin New Material Co., Ltd.;

[0029] Copolymer Nylon Resin #1: PA66 / 6, Grade B50H1, Solvay;

[0030] Copolymer Nylon Resin #2: PA66 / 6T, grade NPD-652, Invista Ltd.;

[0031] Barrier Nylon Resin #1: PA MXD6, Grade MXD6AP 250, Shanghai Yinggu Co., Ltd.;

[0032] Barrier Nylon Resin #2: PA6I / 6T, Grade TI1207, Shandong Guangyin New Material Co., Ltd.;

[0033] Glass fiber: E glass fiber, grade ECS10-3.0-568H, China Jushi Co., Ltd.;

[0034] Organophosphorus flame retardant: diethyl aluminum hypophosphite, grade OP1230, Klein Ltd.;

[0035] Flame retardant synergist #1: Polyvinylpyrrolidone, brand name PVP K90, Shanghai Kema New Materials Co., Ltd.;

[0036] Flame retardant synergist #2: melamine polyphosphate, brand name BUDIT 3141, Budenheim Iberica GmbH, Germany;

[0037] Interface binder #1: 3-aminopropyltriethoxysilane, grade KH550, Chenguang New Materials;

[0038] Interface binder #2: N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane coupling agent, brand name CG-602, Chenguang New Materials;

[0039] Interface binder #3: 3-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent, brand name KH560, Chenguang New Materials;

[0040] Interface binder #4: 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane coupling agent, brand name CG-O186, Chenguang Chemical;

[0041] Interface binder #5: Methyltriethoxysilane coupling agent, brand name CG-106, Chenguang New Materials.

[0042] The preparation method of the nylon composition in the embodiments and comparative examples of the present invention includes the following steps:

[0043] 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;

[0044] 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℃.

[0045] II. Performance Testing Methods

[0046] (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.

[0047] (2) Tensile strength: tested in accordance with ISO 527-2012;

[0048] (3) Notched impact strength of cantilever beam: tested according to ISO 180-2000;

[0049] (4) Adhesion performance test: The nylon strip (150*25*2mm) was first cleaned with ethanol, and then treated with low temperature plasma for 10min. The two treated strips were overlapped with a length of 20mm and coated with addition-type liquid silicone rubber. They were then bonded together by butt joint. A 2000g weight was applied on top and placed at 120℃ for 20min. After cooling, the bonding strength was measured using a tensile testing machine.

[0050] Table 1. Technical solutions and effects of the embodiments (unit: parts by weight)

[0051]

[0052] Table 2 Comparative examples of technical solutions and effects (unit: parts by weight)

[0053]

[0054] Examples 1-9 simultaneously introduce homopolymer nylon resin, copolymer nylon resin, barrier nylon resin, organophosphate, glass fiber, specific flame retardant synergists, and specific interfacial binders. Through the dual effects of barrier nylon and polyvinylpyrrolidone, the migration of flame retardants to the surface is firstly inhibited, thereby improving the bonding strength between organophosphorus flame-retardant nylon and silicone rubber. Secondly, both can promote charring of nylon, thereby improving its flame retardant properties. Utilizing the characteristic that the amorphous molecular chains of copolymer nylon are easily activated, the bonding performance with silicone rubber is improved. The organophosphorus flame-retardant nylon compositions prepared in Examples 1-9 have excellent flame retardant properties, mechanical properties, and silicone rubber bonding properties. Among them, the tensile strength reaches 122 MPa or above, and the cantilever beam notched impact strength reaches 10.8 kJ / m. 2 The silicone bonding strength reaches 3.0 MPa or above.

[0055] As shown in Example 3 and Comparative Example 1, conventional organophosphorus flame-retardant nylon silicone adhesive properties are poor. As shown in Example 3 and Comparative Example 2, without the introduction of barrier nylon, the flame-retardant properties and adhesive strength of the organophosphorus flame-retardant nylon composition are significantly reduced. As shown in Example 3 and Comparative Example 3, without the introduction of copolymer nylon, the adhesive strength of the organophosphorus flame-retardant nylon composition is reduced. Compared to Example 3, Comparative Example 4, Comparative Example 7, and Comparative Example 10, without the introduction of polyvinylpyrrolidone or other flame-retardant synergists, the flame-retardant properties and adhesive strength of the organophosphorus flame-retardant nylon composition are significantly reduced. However, excessive addition of polyvinylpyrrolidone can bind with the nylon molecular chains in the amorphous region, not only deteriorating the mechanical properties of the material but also reducing its silicone adhesive strength. As shown in Example 3, Comparative Example 5, and Comparative Example 8, without the introduction of specific siloxanes containing amino functional groups and / or those containing epoxy functional groups... The mechanical properties and adhesive strength of organophosphorus flame-retardant nylon compositions containing amino groups and siloxanes significantly decreased. This is because specific interfacial binders can not only improve the interfacial interaction between the flame retardant and nylon, thus improving its mechanical properties, but also enhance the interfacial bonding force between nylon and silicone rubber, thereby increasing adhesive strength. However, if the amount of amino siloxane added is too high, the thermal stability of the material will deteriorate, and it will be prone to hydrolysis and cross-linking, resulting in a decrease in its mechanical properties, flame retardant properties, and adhesive properties. As shown in Example 3 and Comparative Example 6, when the content of organophosphorus flame retardant is too high, it is easy to migrate to the surface, thus causing a decrease in the adhesive strength of silicone rubber. As shown in Examples 3, 5, and Comparative Example 9, siloxanes with amino or epoxy groups can improve the flame retardant properties and adhesive strength of organophosphorus nylon compositions. Only siloxanes with amino or epoxy groups can play a good bridging role. None of the above comparative examples can simultaneously achieve good flame retardant properties, mechanical properties, and adhesive strength between the composition and silicone.

[0056] Based on the test data in Tables 1 and 2 regarding vertical burning performance, tensile strength, cantilever beam notched impact strength, and bond strength, 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, characterized in that, By weight, it includes the following components: 25-62 parts of homopolymer nylon resin 5-10 parts of copolymer nylon resin 5-15 parts of barrier nylon resin 20-30 parts glass fiber 8-12 parts of organophosphorus flame retardant 1-4 parts flame retardant synergist 1-3 parts of interface binder; The interface binder is one or more of the following: siloxanes containing amino functional groups or siloxanes containing epoxy functional groups; the flame retardant synergist is polyvinylpyrrolidone. The homopolymer nylon resin is one or more of PA66, PA6, PA56, PA612 or PA610; The copolynylon resin is one or more of PA66 / 6 or PA66 / 6T; The barrier nylon resin is one or more of PA MXD6 or PA6I / 6T.

2. The nylon composition according to claim 1, characterized in that, The organophosphorus flame retardant is one or more of diethylaluminum hypophosphite and diisopropylaluminum hypophosphite.

3. 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.

4. The nylon composition according to claim 1, characterized in that, The interface binder is any one of aminomethoxysilane, aminoethoxysilane, epoxymethoxysilane, or epoxyethoxysilane.

5. A method for preparing the nylon composition according to any one of claims 1-4, 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.

6. The application of the nylon composition according to any one of claims 1-4 in new energy batteries and connectors.

7. Use of the nylon composition according to any one of claims 1-4 in power tools.

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