Flame-retardant high-resistivity bending-resistant polyamide composition and processing method thereof

Abstract

The invention discloses a flame-retardant high-resistivity bending-resistant polyamide composition and a processing method thereof. The composition is mainly composed of polyamide resin, a reactive POE coated red phosphorus flame retardant, carbon nanotubes, high-end amino resin and a dispersing aid. By introducing the reactive POE coated red phosphorus flame retardant, uniform dispersion and stable coating of red phosphorus in a matrix are realized, and excellent flame retardance is ensured; meanwhile, a conductive network is constructed through the carbon nanotubes, so that stable antistatic performance is realized; and through reactivity toughening of the high-end amino resin and the matrix, the bending resistance of the material is remarkably improved. The technical problem that flame retardance, antistatic performance and bending resistance of a polyamide material are difficult to balance is successfully solved, and the obtained composition is excellent in comprehensive performance and suitable for the fields of electronics, electricity, new energy and the like.

Description

Technical Field

[0001] This invention belongs to the field of engineering plastics technology, specifically relating to a flame-retardant, high-resistivity, and flexurally resistant polyamide (PA) composition. Background Technology

[0002] Polyamide (PA) is a widely used engineering plastic, possessing excellent heat resistance, solvent resistance, mechanical properties, and processing performance. It is widely applied in electronics, rail transportation, power tools, home appliances, and sporting goods. With the development of the electronics and new energy industries, increasingly higher demands are being placed on the flame retardancy, electrical properties, and functionalities of materials. Dry-state nylon materials exhibit poor flame retardancy and flexural strength, and their volume resistivity exceeds 10^14, failing to meet the requirements of some flame-retardant and antistatic products. Furthermore, conventional flame-retardant modification further deteriorates flexural performance, while improving flexural performance deteriorates both flame retardancy and resistivity, making a balance difficult to achieve.

[0003] This invention provides a flame-retardant, high-resistivity, and flexurally resistant polyamide (PA) composition that allows the material to maintain both low resistivity and flame-retardant and flexurally resistant properties. Summary of the Invention

[0004] In view of the above problems, the present invention provides a flame-retardant, high-resistivity, and flexurally resistant polyamide composition. By using a reactive POE-coated red phosphorus flame retardant, combined with a carbon nanotube antistatic agent and an auxiliary dispersant, the technical problem of improving flexural resistance while maintaining flame retardant and antistatic effects is solved.

[0005] This invention provides a flame-retardant, high-resistivity, and flexurally resistant polyamide composition, comprising, by weight percentage: 72%-91.5% polyamide resin, 5%-15% reactive polyolefin elastomer-coated red phosphorus flame retardant, 3%-10% carbon nanotubes, 1%-5% high-end amino resin with terminal amino content ≥35 mmol / kg, and 0.5%-3% dispersant and 1%-3% flame retardant; wherein the reactive polyolefin elastomer-coated red phosphorus flame retardant is a core-shell structured particle formed by melt extrusion coating of red phosphorus masterbatch with reactive polyolefin elastomer.

[0006] Optionally, the terminal amino content of the high-end amino resin is 47-85 mmol / kg.

[0007] Optionally, the high-end amino resin is selected from one or more of terminal amino PA66 resin or terminal amino PA56 resin.

[0008] Optionally, in the reactive polyolefin elastomer coated red phosphorus flame retardant, the mass ratio of reactive polyolefin elastomer to red phosphorus masterbatch is 20:80 to 60:40.

[0009] Optionally, the arrayed carbon nanotubes are arrayed carbon nanotubes or wound carbon nanotubes.

[0010] Optionally, the polyamide resin is PA6 resin.

[0011] Optionally, the flame retardant is zinc borate.

[0012] Another aspect of the present invention discloses a method for preparing the aforementioned flame-retardant, high-resistivity, and flexurally resistant polyamide composition, comprising the following steps: Step S1: Mix the formulated amounts of polyamide resin, reactive polyolefin elastomer coated with red phosphorus flame retardant, arrayed carbon nanotubes, high-end amino resin, dispersant and flame retardant to obtain a mixture; Step S2: Add the mixture to a twin-screw extruder for melt blending, extrusion granulation, and obtain the polyamide composition.

[0013] Optionally, in step S2, the extrusion temperature of the twin-screw extruder is 185-195℃ in zone 1, 255-265℃ in zone 2, 265-275℃ in zone 3, 270-280℃ in zone 4, 270-280℃ in zone 5, 270-280℃ in zone 6, 265-275℃ in zone 7, 265-275℃ in zone 8, and 265-275℃ in zone 9; the screw speed is 350-450 rpm.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: while maintaining the flame retardant and antistatic effects, it can also improve the bending resistance. Detailed Implementation

[0015] To better understand the above-described objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can also be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0016] In one specific embodiment of the present invention, a flame-retardant, high-resistivity, and flexurally resistant polyamide composition is provided, comprising, by weight percentage, 72%-91.5% PA6 resin, 1-5% high-end amino PA66 resin, 3%-10% carbon nanotubes, 5%-15% reactive POE (polyolefin elastomer) coated with red phosphorus flame retardant, 0.5%-3% dispersant, and 1%-3% flame retardant.

[0017] Furthermore, the reactive POE-coated red phosphorus flame retardant comprises 20% reactive POE and 80% red phosphorus masterbatch, and is composed of a mixture of 20% reactive POE and 80% red phosphorus masterbatch.

[0018] Furthermore, the reactive POE-coated red phosphorus flame retardant comprises 59% reactive POE, 40% red phosphorus masterbatch, and 1% antioxidant 1098, and is a mixture of 59% reactive POE, 40% red phosphorus masterbatch, and 1% antioxidant 1098.

[0019] Preferably, by weight percentage, it comprises 63.8 parts PA6 resin, 5 parts PA66-EP158 NH, 6 parts carbon nanotubes, 18.8 parts reactive POE-coated red phosphorus flame retardant, 0.2 parts antioxidant and 2 parts flame retardant, wherein 6 parts are reactive POE and 12.8 parts are red phosphorus masterbatch.

[0020] Another specific embodiment of the present invention discloses a method for preparing a flame-retardant, high-resistivity, and flexurally resistant polyamide composition, the specific steps of which are as follows: Step 1. Mix the required raw materials in a high-speed mixer to obtain a mixture; Step 2. Add the mixture to a twin-screw extruder for extrusion granulation to obtain a flame-retardant, high-resistivity, and flexurally resistant polyamide composition.

[0021] Specifically, the twin-screw extruder's screw extrusion zone is divided into nine zones from the inlet to the outlet. The extrusion temperatures of the nine zones are as follows: Zone 1 185-195℃, Zone 2 255-265℃, Zone 3 265-275℃, Zone 4 270-280℃, Zone 5 270-280℃, Zone 6 270-280℃, Zone 7 265-275℃, Zone 8 265-275℃, and Zone 9 265-275℃; the screw speed is 350-450 rpm.

[0022] Furthermore, PA6 is PA6BE3250, manufactured by Jiangsu Hongsheng New Materials Co., Ltd. Furthermore, the red phosphorus masterbatch for the red phosphorus flame retardant is FR9950T, manufactured by Tongcheng Xinde New Materials Co., Ltd.; the reactive POE is KT-915, manufactured by Shenyang Ketong Plastics. Furthermore, the high-end amino PA66 is PA66 EP158 with an amino terminal content of 47 mmol / kg and a relative viscosity of 2.67, or PA66-EP158 NH with an amino terminal content of 82 mmol / kg and a relative viscosity of 2.6, both of which were purchased from Huafeng Group Co., Ltd. Furthermore, the flame retardant is zinc borate HT-207, manufactured by Jinan Taixing Fine Chemical Co., Ltd. Furthermore, the antioxidant is 1098, BASF; Furthermore, the carbon nanotubes are array-type carbon nanotubes GT-300, manufactured by Shandong Dazhan Nanomaterials Co., Ltd. Furthermore, the carbon nanotubes are wound carbon nanotubes GC-30, manufactured by Shandong Dazhan Nanomaterials Co., Ltd.

[0023] This invention prepares POE-coated red phosphorus masterbatch by reacting POE with red phosphorus masterbatch, which increases dispersibility and flame retardancy; at the same time, the system toughness is further improved by the reaction activity of high-end amino PA66 with toughening agent.

[0024] Furthermore, high-end amino PA66 uses the following methods, see Table 1: PA66 resin 1: PA66-EP158 NH, with terminal amino content of 82 mmol / kg and relative viscosity of 2.6, purchased from Huafeng Group Co., Ltd. PA66 Resin 2: PA66 EP158, with terminal amino content of 47 mmol / kg and relative viscosity of 2.67, purchased from Huafeng Group Co., Ltd. PA66 resin 3: PA66-EPR27, with terminal amino content of 40 mmol / kg and relative viscosity of 2.67, purchased from Shenma Group; PA56 resin: PA56 E1273, with terminal amino content of 85 mmol / kg and relative viscosity of 2.7, purchased from Shanghai Kaisai; PA66 Resin 4: PA66 50BWFS, with terminal amino content of 35 mmol / kg and relative viscosity of 2.7, purchased from Ausende.

[0025] Table 1 shows the raw material ratios for 10 embodiments of the present invention.

[0026] Table 2 shows the proportions of each raw material in the three comparative examples.

[0027] The following tests were performed on 10 examples and 3 comparative examples: antistatic testing was conducted according to IEC 62631-3-1:2023; flammability testing was conducted according to UL 94 standard; the test strip thickness was 1.5 mm; and tensile strength was tested according to ISO 527 standard. Bending resistance was tested by repeatedly bending a 125*13*0.8 mm strip at a 45-degree angle until the strip broke. Examples 1, 2, and 3 verify the effect of carbon nanotubes on volume resistivity; the more carbon nanotubes, the lower the volume resistivity. Examples 3-8 verify the effect of terminal amino-terminated PA66 on toughness; the higher the terminal amino content, the higher the toughness. In Example 8, although the terminal amino content was also high, the resin was PA56, resulting in poor toughness. Example 9 verifies the effect of POE addition; the lower the addition, the worse the toughness. In Example 10, although increasing the POE content can increase the number of bends, it leads to flame retardant failure and an increase in volume resistivity. Examples 3 and Comparative Example 1 confirm the effect of PA66 resin; its absence leads to a decrease in bending resistance. Examples 3 and Comparative Example 2 verify the difference between POE-coated red phosphorus masterbatch and red phosphorus masterbatch added alone; adding red phosphorus masterbatch alone leads to a decrease in bending resistance. Examples 3 and Comparative Example 3 verify the effect of POE; not adding POE leads to bending failure.

[0028] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A flame-retardant, high-resistivity, and flexurally resistant polyamide composition, characterized in that, By weight percentage, it comprises 72%-91.5% polyamide resin, 5%-15% reactive polyolefin elastomer-coated red phosphorus flame retardant, 3%-10% carbon nanotubes, 1%-5% high-end amino resin with terminal amino content ≥35mmol / kg, and 0.5%-3% dispersant and 1%-3% flame retardant; wherein the reactive polyolefin elastomer-coated red phosphorus flame retardant is a core-shell structured particle formed by melt extrusion coating of red phosphorus masterbatch with reactive polyolefin elastomer.

2. The flame-retardant, high-resistivity, and flexurally resistant polyamide composition according to claim 1, characterized in that, The terminal amino content of the high-end amino resin is 47-85 mmol / kg.

3. The flame-retardant, high-resistivity, and flexurally resistant polyamide composition according to claim 1, characterized in that, The high-end amino resin is selected from one or more of terminal amino PA66 resin or terminal amino PA56 resin.

4. The flame-retardant, high-resistivity, and flexurally resistant polyamide composition according to claim 1, characterized in that, In the reactive polyolefin elastomer coated with red phosphorus flame retardant, the mass ratio of reactive polyolefin elastomer to red phosphorus masterbatch is 20:80 to 60:

40.

5. The flame-retardant, high-resistivity, and flexurally resistant polyamide composition according to claim 1, characterized in that, The array-type carbon nanotubes are either array-type carbon nanotubes or wound-type carbon nanotubes.

6. The flame-retardant, high-resistivity, and flexurally resistant polyamide composition according to claim 1, characterized in that, The polyamide resin is PA6 resin.

7. The flame-retardant, high-resistivity, and flexurally resistant polyamide composition according to claim 1, characterized in that, The flame retardant is zinc borate.

8. A method for preparing a flame-retardant, high-resistivity, flexurally resistant polyamide composition as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step S1: Mix the formulated amounts of polyamide resin, reactive polyolefin elastomer coated with red phosphorus flame retardant, arrayed carbon nanotubes, high-end amino resin, dispersant and flame retardant to obtain a mixture; Step S2: Add the mixture to a twin-screw extruder for melt blending, extrusion granulation, and obtain the polyamide composition.

9. The preparation method according to claim 8, characterized in that, In step S2, the extrusion temperature of the twin-screw extruder is 185-195℃ in zone 1, 255-265℃ in zone 2, 265-275℃ in zone 3, 270-280℃ in zone 4, 270-280℃ in zone 5, 270-280℃ in zone 6, 265-275℃ in zone 7, 265-275℃ in zone 8, and 265-275℃ in zone 9; the screw speed is 350-450 rpm.

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