A flame retardant polyamide material and its preparation method and application

Abstract

The present invention discloses a flame-retardant polyamide composite material, comprising the following components, by weight: 70-80 parts of polyamide; 12-30 parts of brominated polystyrene; 5-12 parts of an antimony-containing flame retardant synergist; and 6-16 parts of a compounded heat-resistant agent. The compounded heat-resistant agent is a compound of polyethylene and polyethylene glycol, with the weight ratio of polyethylene to polyethylene glycol being (1.5-5):1. The present invention utilizes a compound of high-molecular-weight polyethylene and polyethylene glycol. During melt blending and modification, the hydroxyl groups of the polyethylene glycol can effectively improve the activity of the polyethylene surface, forming a stable interface structure with the polyamide and the entire material system, effectively protecting the material from the influence of external high-temperature and high-humidity environments, thereby improving the material's ability to maintain good performance even after exposure to high-temperature and high-humidity environments. At the same time, the weight-average molecular weight of the brominated polystyrene is on the same order of magnitude as that of polyethylene, thus having excellent compatibility and improving the ability to suppress bending and fracture after high-temperature baking.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, in particular to a flame retardant polyamide material and a preparation method and application thereof. Background Art

[0002] Polyamide, as an engineering material, is widely used in various fields. With the continuous improvement of technology, the product range is also expanding. However, with the development of modern high technology, the number of products requiring durability, friction resistance, and complex structural designs is gradually increasing, placing higher demands on the comprehensive performance of the material. Traditional wear-resistant materials can no longer meet market requirements, and the choice of wear-resistant agents is also limited. Industry colleagues are also conducting different related research.

[0003] CN112430391A describes the use of ultra-high molecular weight polyethylene as an anti-wear agent and polyethylene glycol as a release agent. However, this patent does not focus on heat and moisture resistance and baking resistance.

[0004] CN112552676A records a gas-assisted molding polyamide composite material, including 37-86.7% polyamide resin, 10-40% flat glass fiber, 2-8% impact modifier, 0.5-5% ultra-high molecular weight polyethylene, 0.2-2% polyethylene glycol, 0.1-3% colorant, and 0.5-5% additives. This solution mainly utilizes polyethylene glycol to form intermolecular hydrogen bonds with polyamide, lowering the crystallization temperature of the composite material and improving the appearance. The flat glass fiber helps to provide a more isotropic dispersion and improves the fluidity of the composite material. However, this solution is not able to significantly improve the heat and moisture resistance and the improvement of the baking resistance is also limited. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical defects and provide a flame retardant, high temperature and moisture resistant, and baking resistant polyamide material, as well as a preparation method and application.

[0006] The present invention is achieved through the following technical solutions:

[0007] A flame retardant polyamide material, comprising the following components in parts by weight:

[0008] Polyamide 70-80 parts;

[0009] 12-30 parts of brominated polystyrene;

[0010] 5-12 parts of antimony flame retardant synergist;

[0011] 6-16 parts of compound heat-resistant agent;

[0012] The compound heat-resistant agent is a compound of polyethylene and polyethylene glycol, and the weight ratio of polyethylene to polyethylene glycol is (1.5-5):1;

[0013] The viscosity-average molecular weight of the polyethylene is 400,000-750,000;

[0014] The weight average molecular weight of the polyethylene glycol is 450-12000;

[0015] The weight average molecular weight of the brominated polystyrene is 180,000-250,000.

[0016] The testing method for the weight average molecular weight of brominated polystyrene is: gel permeation chromatography.

[0017] The test method for viscosity-average molecular weight of polyethylene is: GB / T1632.3-2010.

[0018] The weight-average molecular weight of polyethylene glycol is determined as follows: Weigh appropriate amounts of molecular weight reference standards (PEG 600, PEG 1000, PEG 4000, PEG 7000, and PEG 10000), dissolve them in the mobile phase, and dilute to a solution containing approximately 2 mg per 1 ml, which serves as the reference solution. Weigh appropriate amounts of sample, dissolve them in the mobile phase, and dilute to a solution containing approximately 2 mg per 1 ml, which serves as the test solution. Size exclusion chromatography (General Method 0514) is used for determination using a gel column with an appropriate separation range, 0.1 mol / L sodium nitrate solution (containing 0.02% antibacterial agent) as the mobile phase, and a differential refractive index detector. The detector and column temperatures are maintained at 35°C. 100 μl of each reference solution is injected into the liquid chromatograph, and the chromatogram is recorded. The regression equation is calculated using the GPC software. The linear correlation coefficient (R) should be no less than 0.99. Take 100 μl of the test sample solution and perform the same assay. Calculate the weight-average molecular weight and molecular weight distribution of the test sample using the regression equation. The weight-average molecular weight of the test sample should be 90%-110% of the labeled value, and the distribution coefficient should be 90%-110% of the labeled value. The antibacterial agents used are 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one (e.g., ProClin 300), or other small molecule antibacterial agents with equivalent antibacterial potency.

[0019] The weight percentage of polyamide that can achieve the purpose of the present invention can be 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, or 80 parts. The weight percentage of brominated polystyrene can be 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts. The weight percentage of antimony-containing flame retardant synergist can be 5 parts, 7 parts, 9 parts, 10 parts, or 12 parts. The weight percentage of compounded heat-resistant agent can be 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, or 16 parts.

[0020] The viscosity-average molecular weight of the polyethylene that can achieve the purpose of the present invention can be 400,000, 420,000, 440,000, 460,000, 480,000, 500,000, 520,000, 540,000, 560,000, 580,000, 600,000, 620,000, 640,000, 660,000, 680,000, 700,000, 720,000, 750,000, etc.

[0021] The weight average molecular weight of polyethylene glycol that can achieve the purpose of the present invention can be 450, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, etc.

[0022] The weight average molecular weight of the brominated polystyrene that can achieve the purpose of the present invention can be 180,000, 190,000, 200,000, 210,000, 220,000, 230,000, 240,000, 250,000, etc.

[0023] Moreover, in the technical solution of the present invention, the polyamide accounts for no less than 50 wt % of the total weight of the flame retardant polyamide material.

[0024] In the present invention, the polyethylene content ranges from 3.6 to 13.3 parts, and the polyethylene glycol content ranges from 1 to 6.4 parts.

[0025] The polyethylene content that can achieve the purpose of the present invention is 3.6 parts, 4.5 parts, 5.0 parts, 5.5 parts, 6.0 parts, 6.5 parts, 7.0 parts, 7.5 parts, 8.0 parts, 8.5 parts, 9.0 parts, 9.5 parts, 10.0 parts, 10.5 parts, 11.0 parts, 11.5 parts, 12.0 parts, 12.5 parts, 13.0 parts, 13.3 parts, etc.

[0026] The polyethylene glycol content that can achieve the purpose of the present invention is 1 part, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 5.5 parts, 6.0 parts, 6.4 parts, etc.

[0027] Preferably, the weight ratio of polyethylene to polyethylene glycol is (2.4-3.5):1.

[0028] The weight ratio of polyethylene to polyethylene glycol that can achieve the purpose of the present invention is 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, etc.

[0029] The antimony-containing flame retardant synergist is selected from at least one of antimony trioxide and antimony pentoxide.

[0030] Preferably, the weight average molecular weight of the polyethylene glycol is 3800-11000.

[0031] The polyamide resin is selected from at least one of aliphatic polyamide resin, semi-aromatic polyamide resin and polylactam resin.

[0032] The aliphatic polyamide resin is selected from PA66, PA46, PA610, PA612, PA56, PA510, PA512, PA910, PA912, PA913, PA914, PA915, PA616, PA936, PA1010, PA1012, PA1013, PA1014, PA1210, PA1212, PA1213, PA1214, PA614, PA613, PA615, PA616 and the like.

[0033] The semi-aromatic polyamide is selected from PA MXD6, PA10T, PA10T1010, PA10T66, PA6T, PA6T66, PA9T and the like.

[0034] The polylactam is selected from PA5, PA6, PA11, PA12 and the like.

[0035] It is optional to add 0-5 parts of an auxiliary agent according to actual conditions, wherein the auxiliary agent is selected from at least one of a lubricant, a nucleating agent, and an antistatic agent;

[0036] The preparation method of the flame-retardant polyamide material of the present invention comprises the following steps: uniformly mixing various components according to a proportion, putting the components into a twin-screw extruder for melt mixing, and extruding and granulating to obtain the flame-retardant polyamide material; wherein the twin-screw extruder has a screw length-diameter ratio of 40-48:1, a barrel temperature of 230-260°C, and a screw speed of 200-550 rpm.

[0037] The flame retardant polyamide material of the present invention is used for preparing electronic equipment casings.

[0038] The present invention has the following beneficial effects:

[0039] The present invention utilizes a compounding of polyethylene and polyethylene glycol. During melt blending and modification, the hydroxyl groups of the polyethylene glycol effectively improve the activity of the polyethylene surface, forming a stable interface structure with the polyamide and the entire material system, effectively protecting the material from external high-temperature and high-humidity environmental influences, thereby improving the material's ability to maintain good performance even after exposure to high-temperature and high-humidity environments. Furthermore, the polyethylene with a specific viscosity-average molecular weight activated with polyethylene glycol with a specific weight-average molecular weight exhibits good compatibility with high-molecular-weight brominated polystyrene, resulting in a material that not only exhibits flame retardancy but also exhibits excellent bending resistance after high-temperature baking. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0041] The raw materials used in the present invention come from the following sources:

[0042] PA66: PA66 EPR27, Shenma Group;

[0043] PA6: PA6 HY-2800A, marine chemical fiber;

[0044] PA10T: VICNYL 6100P, Zhuhai Wantong Special Engineering Plastics Co., Ltd.

[0045] PA1010: PA1010 G150, Shandong Guangyin New Materials Co., Ltd.;

[0046] Brominated polystyrene A: BPS 7010, Shandong Tianyi, weight-average molecular weight approximately 190,000;

[0047] Brominated polystyrene B: XZ-6700 from Shandong Brothers, weight-average molecular weight approximately 240,000;

[0048] Brominated polystyrene C: SR-3010 Shandong Xurui, weight average molecular weight about 4,000;

[0049] Brominated polystyrene D: FR-803P, ICL, weight average molecular weight of about 600,000.

[0050] Decabromodiphenylethane: SAYTEX 8010, Albemarle Industries;

[0051] Brominated epoxy: CXB-2000 WOOJIN COPOLYMER;

[0052] Antimony trioxide: S-05N Shanxing Antimony Industry;

[0053] Polyethylene A: viscosity-average molecular weight about 400,000, GUR 2105, Celanese;

[0054] Polyethylene B: viscosity-average molecular weight about 560,000, L0504F, Sinopec;

[0055] Polyethylene C: viscosity-average molecular weight about 140,000, LA0710, Qatar;

[0056] Ultra-high molecular weight polyethylene: PE-UHMW MI, Sinopec, viscosity-average molecular weight of approximately 1.57 million;

[0057] Polyethylene glycol A: weight average molecular weight 500, PEG-500, Shanghai Haoyuan Biopharmaceutical Technology Co., Ltd.;

[0058] Polyethylene glycol B: weight average molecular weight 4000, PEG-4000, Shanghai Haoyuan Biopharmaceutical Technology Co., Ltd.;

[0059] Polyethylene glycol C: weight average molecular weight 8000, PEG-8000, Shanghai Haoyuan Biopharmaceutical Technology Co., Ltd.;

[0060] Polyethylene glycol D: weight average molecular weight 10000, PEG-10000, Shanghai Haoyuan Biopharmaceutical Technology Co., Ltd.;

[0061] Polyethylene glycol E: weight average molecular weight 15000, PEG-15000, Shanghai Haoyuan Biotechnology Co., Ltd.

[0062] The flame-retardant polyamide material of the embodiment and comparative example is prepared by uniformly mixing the components according to the ratio, putting them into a twin-screw extruder for melt mixing, and extruding and granulating to obtain a flame-retardant polyamide material; wherein the screw aspect ratio of the twin-screw extruder is 44:1, the barrel temperature is 230~260℃, and the screw speed is 400rpm.

[0063] Various test methods:

[0064] (1) Resistance to heat and humidity aging: Flame-retardant polyamide material was injection molded into a 100*100*1.5mm square plate and stored at 75°C and 75% humidity for 500 hours. The material was then tested for its drop ball impact performance. The specific test method is as follows: a 2kg steel ball was used to perform a drop ball impact test at a height of 1.5m at room temperature. The sample cracking grade is as follows: obvious cracking is considered level 3, cracking but no cracking is considered level 2, and no visible cracking is considered level 1.

[0065] (2) Flame retardancy: UL-94 is used to test the flame retardancy level of materials, which are divided into V-0, V-1 and V-2.

[0066] (3) Bending performance after high temperature baking: The prepared material was placed in an injection molding machine at 275°C for 5 minutes, and a 280T injection molding machine was used to mold the specimen at a rated speed of 50% and a pressure of 60 bar. High temperature performance test: A 100*13*0.8mm sample was prepared and dried at 175°C for 4 hours. The sample was taken out and bent at 90°C within 1 minute. Repeat N times. The sample was considered qualified if it did not break after 3 times. The more times, the better.

[0067] Table 1: Content (parts by weight) of each component of flame-retardant polyamide materials in Examples 1-7 and test results

[0068] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PA66 75 75 75 75 PA6 70 PA10T 75 PA1010 80 Brominated polystyrene A 18 14 22 30 18 18 Brominated polystyrene B 18 Antimony trioxide 7 5 10 12 7 7 7 Polyethylene A 7.5 4.5 9 12 7.5 6 Polyethylene B 7.5 Polyethylene glycol B 2.5 1.5 3 4 2.5 2.2 4 Polyethylene:polyethylene glycol weight ratio 3 3 3 3 3 3.4 1.5 flame retardancy V-0 V-0 V-0 V-0 V-0 V-0 V-0 Impact resistance after heat and humidity aging 1 1 1 1 1 1 2 Heat resistance after bending, secondary 8 7 7 6 7 5 5

[0069] Table 2: Content (parts by weight) of each component of flame-retardant polyamide materials in Examples 8-13 and test results

[0070] Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 PA66 75 75 75 75 75 75 Brominated polystyrene A 18 18 18 18 18 18 Antimony trioxide 7 7 7 7 7 7 Polyethylene A 7.1 7.8 8.3 7.5 7.5 7.5 Polyethylene glycol B 2.9 2.2 1.7 Polyethylene glycol A 2.5 Polyethylene glycol C 2.5 Polyethylene glycol D 2.5 Polyethylene:polyethylene glycol weight ratio 2.4 3.5 4.9 3 3 3 flame retardancy V-0 V-0 V-0 V-0 V-0 V-0 Resistance to heat and humidity aging impact 1 1 2 2 1 1 Heat resistance after bending, secondary 6 6 5 6 8 7

[0071] It can be seen from Examples 1 / 7 / 8 / 9 / 10 that the preferred weight ratio of polyethylene to polyethylene glycol results in better resistance to wet heat aging.

[0072] It can be seen from Examples 1 / 11 / 12 / 13 that the preferred polyethylene glycol weight average molecular weight has better resistance to moist heat aging.

[0073] Table 3: Content of each component (parts by weight) and test results of flame retardant polyamide materials in comparative examples 1-6

[0074] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 PA66 75 75 75 75 75 75 Brominated polystyrene A 18 18 18 18 18 Brominated polystyrene C 18 Antimony trioxide 7 7 7 7 7 7 Polyethylene A 7.5 7.5 5 9 Polyethylene C 7.5 Ultra-high molecular weight polyethylene 7.5 Polyethylene glycol B 2.5 2.5 2.5 5 1 Polyethylene glycol E 2.5 Polyethylene:polyethylene glycol weight ratio 3 3 3 3 1 9 flame retardancy V-2 V-2 V-2 V-2 V-2 V-2 Resistance to heat and humidity aging impact 3 3 3 3 3 3 Heat resistance after bending, secondary 1 2 1 2 2 1

[0075] Comparative Example 1 shows that if the molecular weight of brominated polystyrene is too low, not only is the flame retardancy insufficient, but also due to its low molecular weight it is difficult to cooperate with the molecular weight of polyethylene, resulting in poor resistance to wet heat aging and reduced flame retardancy.

[0076] Comparative Example 2 shows that polyethylene with too low a viscosity-average molecular weight has poor bending properties. Therefore, the bending properties of the flame-retardant polyamide material used in the present invention are insufficient. Due to unknown factors, the flame retardancy and resistance to wet heat aging are also reduced.

[0077] It can be seen from Comparative Example 3 that if the viscosity-average molecular weight of polyethylene is too high, its compatibility with brominated polystyrene is poor, resulting in poor resistance to wet heat aging and reduced flame retardancy.

[0078] It can be seen from Comparative Example 4 that if the weight average molecular weight of polyethylene glycol is too low, it will also lead to poor resistance to moist heat aging and reduce flame retardancy.

[0079] It can be seen from Comparative Examples 5-6 that if the ratio of polyethylene to polyethylene glycol is not within the range of the present invention, both the wet heat aging resistance and the flame retardancy are poor.

[0080] Table 4: Content of each component (parts by weight) and test results of flame retardant polyamide materials in comparative examples 7-9

[0081] Comparative Example 7 Comparative Example 8 Comparative Example 9 PA66 75 75 75 Decabromodiphenylethane 18 Epoxy Bromide 18 Brominated polystyrene D 18 Antimony trioxide 7 7 7 Polyethylene A 7.5 7.5 7.5 Polyethylene glycol B 2.5 2.5 2.5 Polyethylene:polyethylene glycol weight ratio 3 3 3 flame retardancy V-0 V-2 V-1 Resistance to heat and humidity aging impact 3 3 3 Heat resistance after bending, secondary 1 1 1

[0082] Comparative Example 7 shows that when decabromodiphenylethane is used, V-0 flame retardancy can be obtained due to its high bromine content, but the heat resistance / wet heat aging resistance is poor.

[0083] It can be seen from Comparative Example 8 that when brominated epoxy is selected as the flame retardant, the compatibility with the system is poor and the overall performance is poor.

[0084] It can be seen from Comparative Example 9 that when the molecular weight of brominated polystyrene is too high, its dispersibility in the system is poor, V-0 flame retardancy cannot be obtained, and the heat resistance / humid heat aging resistance is poor.

Claims

1. A flame retardant polyamide material, characterized in that: Calculated by weight, it includes the following components: Polyamide 70-80 parts; 12-30 parts of brominated polystyrene; 5-12 parts of antimony flame retardant synergist; 6-16 parts of compound heat-resistant agent; The compound heat-resistant agent is a compound of polyethylene and polyethylene glycol, and the weight ratio of polyethylene to polyethylene glycol is (1.5-5):1; The viscosity-average molecular weight of the polyethylene is 400,000-750,000; The weight average molecular weight of the polyethylene glycol is 450-12000; The weight average molecular weight of the brominated polystyrene is 180,000-250,000.

2. The flame retardant polyamide material according to claim 1, characterized in that The weight ratio of polyethylene to polyethylene glycol is (2.4-3.5):

1.

3. The flame retardant polyamide material according to claim 1, characterized in that The antimony-containing flame retardant synergist is selected from at least one of antimony trioxide and antimony pentoxide.

4. The polyamide material according to claim 1, characterized in that The weight average molecular weight of the polyethylene glycol is 3800-11000.

5. The flame retardant polyamide material according to claim 1, characterized in that The polyamide resin is selected from at least one of aliphatic polyamide resin and semi-aromatic polyamide resin.

6. The flame retardant polyamide material according to claim 1, characterized in that The polyamide resin is selected from polylactam resin.

7. The flame retardant polyamide material according to claim 1, characterized in that: The invention further comprises 0-5 parts of auxiliary agents in parts by weight, wherein the auxiliary agents are selected from at least one of lubricants, nucleating agents and antistatic agents.

8. The method for preparing the flame retardant polyamide material according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: uniformly mixing the components according to a proportion, feeding the components into a twin-screw extruder for melt mixing, and extruding and granulating to obtain a flame-retardant polyamide material; wherein the twin-screw extruder has a screw length-diameter ratio of 40-48:1, a screw barrel temperature of 230-260°C, and a screw speed of 200-550 rpm.

9. Use of the flame retardant polyamide material according to any one of claims 1 to 6, characterized in that: Used to prepare electronic equipment casings.