Nylon composite material, and preparation method therefor and use thereof

Abstract

The present invention relates to the field of halogen-free organophosphorus flame-retardant nylon, and in particular to a nylon composite material, and a preparation method therefor and a use thereof. Specifically, the nylon composite material disclosed in the present invention comprises: 65-82 parts of polyamide resin, 12-18 parts of a hypophosphite flame retardant, 10-50 parts of a reinforcing agent, 0.5-2 parts of hydrotalcite, 3-8 parts of boehmite, and 1-3 parts of PET resin. The present invention solves the problem of corrosion of organophosphorus flame-retardant nylon materials to silicone under high-temperature conditions, and provides an organophosphorus flame-retardant nylon composite material resistant to silicone corrosion under high-temperature conditions, having a high CTI value and meeting the UL94 V0 flame retardant rating.

Description

A nylon composite material, its preparation method and application Technical Field

[0001] This invention belongs to the field of halogen-free organophosphorus flame-retardant nylon, and specifically relates to a nylon composite material, its preparation method, and its application. Background Technology

[0002] Polyamide resins possess excellent comprehensive properties, including mechanical properties, barrier properties, heat resistance, wear resistance, and chemical corrosion resistance. Their composite materials are widely used in machinery manufacturing, industrial connectors, power tools, electronics, and transportation.

[0003] Among its many applications, nylon is increasingly used in high-voltage connectors for new energy applications. Energy storage connectors are a part of high-voltage connectors for new energy applications, and have very high material requirements.

[0004] 1. High IPT characteristics: According to the UL4128 outline for inter-cell and inter-layer connectors for electrochemical battery systems, when the rated voltage is greater than 600V to 2000V and the creepage distance between electrodes is less than 16mm, the IPT performance of the material must be tested. There are many material solutions with IPT ≤ 1.0KV, but very few materials with IPT ≥ 1.5KV.

[0005] 2. High RTI value requirement: A higher RTI value indicates better long-term high-temperature resistance and a longer service life. As energy storage connectors carry larger currents and generate more heat, higher requirements are placed on the long-term heat resistance of the materials.

[0006] 3. Resistant to silicone corrosion: Energy storage connectors are often located in unattended environments, so they have strict protective sealing requirements for harsh environments such as high humidity and high dust. Silicone rubber is used as a sealing material in these environments. However, some flame-retardant materials are highly acidic and can easily corrode silicone, especially under high temperature conditions for a long time. This corrosion can severely affect the sealing performance of the product and lead to product failure.

[0007] 4. Highly efficient flame retardant, all colors meet UL94 V0 flame retardant requirements. Energy storage connectors operate with electricity for extended periods, requiring higher electrical safety standards, and the materials must meet UL94 V0 flame retardant requirements.

[0008] Among numerous flame-retardant systems, halogen-free organophosphorus flame retardants possess many advantages, including low smoke and halogen-free properties, high flame retardancy, high CTI (color matching), and good mechanical properties, making them widely used in the field of new energy connectors. However, current technologies have not provided an effective solution to the corrosion problem of silicone by organophosphorus flame-retardant nylon materials under high-temperature conditions, which adversely affects the application and promotion of high-voltage connector products in the new energy sector. Summary of the Invention

[0009] The purpose of this invention is to solve the above-mentioned technical problems and provide a nylon composite material that is resistant to silicone corrosion under high temperature conditions, has a high CTI value, and meets the UL94 V0 flame retardant rating.

[0010] Another object of the present invention is to provide a method for preparing the above-mentioned nylon composite material.

[0011] Another object of the present invention is to provide applications of the above-mentioned nylon composite material.

[0012] This invention is achieved through the following technical solution:

[0013] A nylon composite material, by weight, contains the following components:

[0014] 65-82 parts of polyamide resin;

[0015] 12-18 parts of hypophosphite flame retardant;

[0016] 10-50 parts of reinforcing agent;

[0017] 0.5-2 parts of hydrotalcite;

[0018] Boehmite 3-8 parts;

[0019] 1-3 parts of PET resin.

[0020] Preferably, the mineral modifier is selected from a compound of hydrotalcite and boehmite, with a weight ratio of hydrotalcite:boehmite = 1:(4-7).

[0021] The D50 particle size range of hydrotalcite is 0.1μm to 0.8μm. The D50 particle size test method is to place 1g of hydrotalcite in 500ml of ethanol solution, disperse it by ultrasonic vibration for 5min, shake it well, and then take the suspension into a Darwin particle size analyzer to obtain the D50 value.

[0022] Preferably, the polyamide resin is selected from any one or more of PA66, PA610, PA612, PA1012, PA46, MXD6, PA6, PA7, PA11, PA12, PA6T or PA66 / 6T.

[0023] More preferably, it is any one or more of PA6, PA66, or PA66 / 6T;

[0024] A further preferred option is PA66 / 6T.

[0025] In the nylon composite material of the present invention, the polyamide resin preferably accounts for 40-78 wt% of the total weight.

[0026] Preferably, the terephthalic acid monomer unit mass percentage in the PA66 / 6T resin is 22%-28%.

[0027] Preferably, the hypophosphite flame retardant is selected from diethylaluminum hypophosphite.

[0028] Preferably, the reinforcing agent is selected from any one or more of glass fibers or mineral fillers; more preferably, it is glass fiber.

[0029] Preferably, the glass fiber is selected from any one or more of chopped raw glass fibers A-, E-, C-, D-, S- and R-; the cross-section of the glass fiber is circular or non-circular.

[0030] The diameter of the glass fiber ranges from 6μm to 15μm, and the length ranges from 1.0mm to 10mm.

[0031] Preferably, the D50 particle size of the boehmite is 0.1-2.5 micrometers; more preferably 0.5-0.8 micrometers. The D50 particle size test method is as follows: 1g of boehmite is placed in 500ml of ethanol solution, ultrasonically dispersed for 5min, shaken well, and then the suspension is taken into a Darwin particle size analyzer to obtain the D50 value.

[0032] Preferably, the intrinsic viscosity of the polyethylene terephthalate resin is 0.6-1.1 dl / g, more preferably 0.65-0.88 dl / g, and the test is performed according to ISO 1628-1.

[0033] This invention provides a method for preparing the above-mentioned nylon composite material, comprising the following steps: mixing all components except the reinforcing agent evenly according to the formula, adding the mixture from the feed port of the first section of the twin-screw extruder, adding the reinforcing agent from the fifth section of the screw, and then performing melt extrusion granulation. The corresponding screw temperatures of the extruder are 80℃, 240℃, 270℃, 270℃, 250℃, 240℃, 240℃, 250℃, and 270℃, respectively, and the screw speed range is 300rpm to 500rpm. After cooling and pelletizing, the nylon composite material is obtained.

[0034] This invention provides an application of the aforementioned nylon composite material for the manufacture of energy storage connector components.

[0035] The present invention has the following beneficial effects:

[0036] Organophosphorus flame retardants corrode silicone rubber under high-temperature conditions. Diethylphosphonate is inherently acidic, with a pH value of 3.0-5.0. Its acidity intensifies under high temperatures, and it easily decomposes into acidic substances such as phosphates and diethylphosphonic acid when heated. These substances react with the Si-O bonds in silicone rubber, causing them to break down and sever, resulting in permanent deformation of the silicone rubber and affecting the product's sealing performance. However, this process does not occur at room temperature, so the problem of silicone corrosion only manifests when the product is in a specific environment.

[0037] This invention uses boehmite as a synergistic flame retardant, without introducing MPP, which is beneficial for flame retardancy. The main reason is that MPP is highly acidic and easily migrates to the sample surface, which would accelerate the corrosion of silicone. Secondly, layered silicates such as hydrotalcite are introduced, which have strong acid absorption properties, reducing the acidity of the system and reducing the high-temperature degradation reaction of silicone by acidic substances. Finally, a small amount of PET resin is introduced, which has poor compatibility with nylon and will accumulate on the surface of the product during injection molding, forming a kind of membrane, reducing the migration of organophosphorus flame retardants to the surface, and further weakening the interaction between flame retardant and silicone.

[0038] Through the combined effect of these factors, the composite material exhibits excellent silicone corrosion resistance without compromising high CTI characteristics and flame retardant rating, making it a promising candidate for application in high-voltage connectors for new energy sources, especially energy storage connectors.

[0039] The solution of this invention is highly feasible and effective, and its operation is simple and efficient.

[0040] Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0042] Sources of raw materials used in this invention:

[0043] Nylon 66: PA66 EP-158, Huafeng Group Co., Ltd.

[0044] Nylon 6: PA6 HY-2500A, Haiyang Technology Co., Ltd.

[0045] Nylon 66 / 6T: NPD-652, Invista (China) Investment Co., Ltd.

[0046] Nylon 1012: PA1012 RV26, Cangzhou Lingang Anaiji New Materials Co., Ltd.

[0047] MXD6: PA MXD6 M30L, Shanghai Yinggu Chemical Co., Ltd.

[0048] Nylon 12: VESTAMID L1940 NC, Evonik Industries.

[0049] Diethylaluminum hypophosphite: OP 1230, Clariant Chemicals Ltd.

[0050] Wollastonite: HQ-1250, Dalian Global Minerals Co., Ltd.

[0051] Fiberglass: ECS10-03-568H, China Jushi Co., Ltd.

[0052] Hydrotalcite 1: AC-320, D50 particle size is 0.1μm, Chenghe Technology.

[0053] Hydrotalcite 2: DHT-4A, D50 particle size 0.4μm, Kyowa Chemical Industry Co., Ltd., Japan.

[0054] Hydrotalcite 3: FM300 FM803, D50 particle size is 0.8μm, Kanggaote New Material Technology Co., Ltd.

[0055] Boehmite 1: BG-613SO, D50 particle size 1.75μm, Anhui Yishitong Materials Technology Co., Ltd.

[0056] Boehmite 2: LSB-2-2, D50 particle size 0.65μm, China Aluminum Zhengzhou Nonferrous Metals Research Institute Co., Ltd.

[0057] Boehmite 3: B8014-LM, D50 particle size 0.15μm, Tianjin Boyuan High-Tech Materials Co., Ltd.

[0058] PET Resin 1: Polyethylene terephthalate resin, model PET BG80, relative density 1.34, intrinsic viscosity 0.80 dl / g, purchased from Yizheng Branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0059] PET Resin 2: Polyethylene terephthalate resin, model PET SY-G105, with a relative density of 1.34 and an intrinsic viscosity of 1.09 dl / g, purchased from Shuangyang Polyester Modification Plant in Wujiang City.

[0060] PET resin 3: Polyethylene terephthalate resin, model PET CR-7702, with a relative density of 1.31 and an intrinsic viscosity of 0.50 dl / g, purchased from China Resources Packaging Materials Co., Ltd.

[0061] Test methods:

[0062] (1) Evaluation of silicone corrosion: A 60*60*3.0mm square plate was injection molded. A circular silicone ring with a diameter of 10mm and a thickness of 4mm was placed flat in the center of the square plate. Then the square plate was covered, and the position of the silicone ring was kept unchanged. Then a 200g weight was placed in the center of the top cover plate. The entire device was then placed in a 120℃ oven for 672h. Finally, the thickness of the silicone ring was recorded, and the height change rate of the silicone ring was calculated. The greater the change rate, the more permanent deformation of the silicone occurred, and the more severe the corrosion of the silicone by the material.

[0063] (2) Tracking index (CTI) of plastic raw materials: Tested according to GB / T4207-2012, sample size: 60mm*60mm*3.0mm, CTI test range is (0~1000)V.

[0064] (3) Flame retardancy rating test: The test is conducted in accordance with the UL 94 standard, and the test strip size is 125mm*13mm*1.6mm.

[0065] Table 1. Weight parts and test results of each component of the nylon composite materials in Examples 1-9

[0066] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Nylon 67638 Nylon 667638 Nylon 66 / 6T658276 Nylon 1276 Nylon 121276 MXD676 Diethylaluminum hypophosphite 181215151515151515 Glass fiber 501035353535353535 Hydrotalcite 220.5111111 1 Boehmite 2835555555 PET Resin 1312222222 Silicone Corrosion 6.82% 7.36% 9.50% 8.10% 5.80% 7.80% 7.70% 6.30% 8.40% Tracking Index / V 600 700 700 700 750 725 725 600 700 Flame Retardant Rating V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0

[0067] Table 2. Weight parts and test results of each component of the nylon composite material in Examples 10-18

[0068] Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Nylon 66 / 6T7676767676767676 Diethylaluminum hypophosphite 151515151515151515 Wollastonite 35 Glass fiber 3535353535353535 Hydrotalcite 11 Hydrotalcite 21111161 Hydrotalcite 31 Boehmite 15 Boehmite 25555 5515 Boehmite 35 PET Resin 12222222 PET Resin 22 PET Resin 32 Silicone Corrosion 9.10% 5.94% 6.31% 8.90% 9.00% 8.80% 9.20% 13.60% 12.20% Tracking Index / V 650 750 750 650 650 650 600 600 600 Flame Retardant Rating V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0

[0069] As can be seen from Examples 3-9, under the same conditions and other components, using Nylon 66 / 6T can reduce the corrosion resistance of silicone to 5.80%, increase the tracking index to 750V, and at the same time meet the flame retardant rating of V-0.

[0070] As can be seen from Examples 5 and 10, under the same conditions and other components, glass fiber as a reinforcing agent has better effects on silicone corrosion and tracking index compared to mineral filler.

[0071] As can be seen from Examples 5 and 11-12, under the same conditions and other components, using hydrotalcite D50 with a particle size range of 0.3-0.5 μm has better results.

[0072] As can be seen from Examples 5 and 13-14, under the same conditions and other components, the boehmite with a particle size of 0.5-0.8 micrometers has better performance in the tests of silica gel corrosion and tracking index.

[0073] As can be seen from Examples 5 and 15-16, under the same conditions and with other components, the intrinsic viscosity of the PET resin is preferably 0.6 to 1.1 dl / g, and more preferably 0.65 to 0.88 dl / g.

[0074] As can be seen from Examples 5 and 17-18, under the same conditions and other components, adding an excessive amount of hydrotalcite or boehmite will improve the corrosion resistance of silicone while reducing the tracking index to 600V.

[0075] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Nylon 66 / 6T 76767676 Diethylaluminum hypophosphite 15 15 15 15 Glass fiber 35 35 35 35 Hydrotalcite 26 11 Boehmite 26 55 PET resin 12 25 Silicone corrosivity 18.92% 19.14% 17.50% 14.60% Tracking index / V 650 650 700 500 Flame retardant rating V-0 V-2 V-0 V-2

[0076] As shown in Comparative Example 1, the absence of hydrotalcite has a significant impact on the corrosivity of silica gel.

[0077] As shown in Comparative Example 2, the absence of boehmite increases the corrosivity of silicone in nylon composite materials, reduces the tracking index, and prevents the flame retardant rating from reaching V-0.

[0078] As shown in Comparative Example 3, the absence of PET resin increased the corrosivity of silicone.

[0079] As shown in Comparative Example 4, adding excessive PET resin has a significant impact on the tracking index, which drops to 500V.

Claims

1. A nylon composite material, characterized in that, Based on parts by weight, it contains the following ingredients: 65-82 parts of polyamide resin; 12-18 parts of hypophosphite flame retardant; 10-50 parts of reinforcing agent; 0.5-2 parts of hydrotalcite; Boehmite 3-8 parts; 1-3 parts of PET resin.

2. The nylon composite material according to claim 1, characterized in that, The polyamide resin is selected from any one or more of PA66, PA610, PA612, PA1012, PA46, MXD6, PA6, PA7, PA11, PA12, PA6T or PA66 / 6T; preferably any one or more of PA6, PA66 or PA66 / 6T; more preferably PA66 / 6T.

3. The nylon composite material according to claim 1, characterized in that, The hypophosphite flame retardant is selected from diethylaluminum hypophosphite.

4. The nylon composite material according to claim 1, characterized in that, The reinforcing agent is selected from any one or more of glass fibers or mineral fillers; preferably glass fibers.

5. A nylon composite material according to claim 4, characterized in that, The glass fiber is selected from any one or more of chopped raw glass fibers A-, E-, C-, D-, S- and R-; the cross-section of the glass fiber is circular or non-circular.

6. The nylon composite material according to claim 1, characterized in that, The D50 particle size of the boehmite is 0.1-2.5 micrometers, preferably 0.5-0.8 micrometers.

7. The nylon composite material according to claim 1, characterized in that, The intrinsic viscosity of the polyethylene terephthalate resin is 0.6-1.1 dl / g, preferably 0.65-0.88 dl / g.

8. A method for preparing a nylon composite material according to any one of claims 1-7, characterized in that, The process includes the following steps: According to the formula, all components except the reinforcing agent are mixed evenly and added from the feed port of the first section of the twin-screw extruder. The reinforcing agent is added from the fifth section of the screw. Then, melt extrusion granulation is carried out. The corresponding screw temperatures of the extruder are 80℃, 240℃, 270℃, 270℃, 250℃, 240℃, 240℃, 250℃ and 270℃, and the screw speed range is 300rpm~500rpm. After cooling and pelletizing, nylon composite material is obtained.

9. The application of the nylon composite material according to any one of claims 1-7, characterized in that, Used to manufacture energy storage connector components.