Low-mold-fouling flame-retardant polyamide composite material, preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a low-mold-fouling flame-retardant polyamide composite material, a preparation method therefor and a use thereof. The polyamide composite material comprises the following components in parts by weight: 40-60 parts of a polyamide resin; 13-30 parts of aluminum diethylphosphinate; 4-10 parts of a synergistic flame retardant; 15-40 parts of glass fibers; 0.1-5 parts of an ethylene-maleic anhydride copolymer; and 0.1-2 parts of a thermal stabilizing additive. The thermal stabilizing additive is a phosphite ester. The polyamide composite material of the present invention solves the problem of heavy mold fouling of flame-retardant polyamides, has high notched impact strength, and can meet the requirements of industries such as automobiles, electronics, energy storage, and connectors.

Description

A low-fouling flame-retardant polyamide composite material, its preparation method and application Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a low-fouling flame-retardant polyamide composite material, its preparation method, and its application. Background Technology

[0002] Polyamide, commonly known as nylon, is an important thermoplastic engineering plastic. Due to its excellent mechanical strength, heat resistance, and chemical resistance, it is used in various fields such as automotive parts, mechanical components, and electrical systems. Phosphinate flame-retardant polyamides, due to their excellent comprehensive mechanical properties, ease of coloring, ease of processing, and high CTI (Complexity Intensity), are commonly used in connectors, low-voltage electrical appliances, and energy storage industries. However, phosphinate flame-retardant polyamides have heavy molding residue, making them difficult to apply in the automotive and electronics industries. Therefore, there is an urgent need for a flame-retardant polyamide composite material with low molding residue and high impact strength to meet the needs of the automotive, electronics, energy storage, connector, and rail transportation industries. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a low-fouling flame-retardant polyamide composite material, its preparation method, and its applications.

[0004] This invention provides a flame-retardant polyamide composite material, comprising the following components in parts by weight:

[0005] The composition includes: 40-60 parts of polyamide resin, preferably 45-55 parts; 13-30 parts of aluminum diethylphosphinate, preferably 15-25 parts; 4-10 parts of synergistic flame retardant, preferably 5-8 parts; 15-40 parts of glass fiber, preferably 20-30 parts; 0.1-5 parts of ethylene-maleic anhydride copolymer, preferably 1-3 parts; and 0.1-2 parts of heat stabilizer, preferably 0.2-1 parts.

[0006] The heat-stabilizing agent is a phosphite, including any one of amino phosphites, phenolic phosphites, aliphatic amide phosphites, nitrile amide phosphites, and nitrile amide phosphites.

[0007] Furthermore, the heat stabilizing agent is spirophosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, or tris(2,4-di-tert-butylphenyl) phosphite.

[0008] The polyamide resin accounts for a minimum percentage of 30% of the flame-retardant polyamide composite material, preferably 40%.

[0009] Further, the weight ratio of the ethylene-maleic anhydride copolymer to the heat stabilizer is (0.5-8):1, such as 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1, preferably (3-5):1.

[0010] Further, the polyamide resin is a condensation product of one or more dicarboxylic acids and one or more diamines, or the polyamide is a condensation product of one or more aminocarboxylic acids, or the polyamide is a ring-opening polymerization product of one or more lactams.

[0011] Furthermore, the relative viscosity of the polyamide resin is 2.0 to 5.1, preferably 2.4 to 3.2.

[0012] The method for determining relative viscosity is as follows: Weigh 0.5g of polyamide resin, transfer it to a 50mL volumetric flask, add approximately 40mL of 96% concentrated sulfuric acid, and sonicate until the polyamide resin is completely dissolved. Cool the solution to 25℃, dilute it to the mark with concentrated sulfuric acid, and mix thoroughly. Measure the flow time of the 0.01g / mL polyamide resin solution at 25℃ through an Ubbelohde viscometer, and record it as t1. Measure the flow time of the concentrated sulfuric acid solvent using the same viscometer, and record it as t2. t1 / t2 is the relative viscosity of the polyamide resin.

[0013] Furthermore, the synergistic flame retardant is one or more of melamine polyphosphate, melamine aluminum polyphosphate, melamine magnesium polyphosphate, melamine zinc polyphosphate, and zinc borate.

[0014] Furthermore, the glass fiber is one or more of E glass fiber, A glass fiber, S glass fiber, D glass fiber, C glass fiber, and quartz glass fiber.

[0015] Further, the weight-average molecular weight of the ethylene-maleic anhydride copolymer is 5,000 to 400,000, preferably 8,000 to 70,000. Using a Waters e-Alliance GPC system gel permeation chromatography, 2.5 mg of the analyte was dissolved in 4 mL of hexafluoroisopropanol solvent (containing 0.005 N sodium trifluoroacetate), and then filtered through a 0.45 μm filter. The test filtrate was used to determine the weight-average molecular weight (Mn).

[0016] Furthermore, the content of maleic anhydride in the ethylene-maleic anhydride copolymer is >70 wt%.

[0017] Preferably, the ethylene-maleic anhydride copolymer is an alternating copolymer with the following structural formula:

[0018] Where n is the degree of polymerization, and the range of n is 78 to 468.

[0019] Furthermore, the flame-retardant polyamide composite material also includes an antioxidant, wherein the antioxidant is present in an amount of 0 to 0.8 parts by weight;

[0020] Furthermore, the antioxidant is one or more of hindered phenolic antioxidants, amine antioxidants, cuprous halide composite antioxidants, or antioxidants containing benzophenone functional groups.

[0021] Furthermore, the polyamide composite material further includes 0 to 1 part of a lubricant, wherein the lubricant is at least one of hydrocarbons, esters, alcohols, fatty acids, fatty acid amides, and metal soaps; preferably, ester lubricants, such as fatty acid esters, polyol esters, and polyethylene glycol esters.

[0022] The present invention also provides a method for preparing the flame-retardant polyamide composite material, comprising the following steps:

[0023] Weigh each component by weight, and mix all components except glass fiber in a high-speed mixer for 3-10 minutes. Then add the mixture to the main feed hopper of a twin-screw extruder. Add glass fiber from the side feed hopper of the sixth screw section. After fully plasticizing and melting, extrude, stretch, cool, and pelletize to obtain the flame-retardant polyamide composite material. The screw speed of the twin-screw extruder is 300-800 rpm, the length-to-diameter ratio is 36:1-48:1, the temperature of each section of the extruder barrel is 160℃-250℃, and the die head temperature is 230℃-260℃.

[0024] The present invention also provides the application of the flame-retardant polyamide composite material in the preparation of automotive, electronic and electrical materials and rail transportation, such as automotive connectors and low-voltage electrical products in electronics and electrical systems.

[0025] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0026] (1) The polyamide composite material of the present invention produces low mold fouling weight.

[0027] (2) The polyamide composite material of the present invention can maintain a high notched impact strength while reducing mold fouling. Detailed Implementation

[0028] 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.

[0029] Example

[0030] 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.

[0031] I. The sources of raw materials for the examples and comparative examples are as follows:

[0032] Polyamide resin A: Nylon 66, PA66EPR24, relative viscosity 2.4, Shenma Group;

[0033] Polyamide resin B: Nylon 66, grade PA66EPR32, relative viscosity 3.2, Shenma Group;

[0034] Polyamide resin C: Nylon 66, grade PA66T51, relative viscosity 5.1, Huafeng Group Co., Ltd.

[0035] Aluminum diethylphosphinic acid: Exolit OP 1230, Clariant;

[0036] Synergistic flame retardant A: Bubit 3141, melamine polyphosphate, Bode;

[0037] Synergistic flame retardant B: Magnesium hydroxide, brand name Aitemag 12FD, Jiangsu Aiteke;

[0038] Glass fiber A:E glass fiber, grade ECS10-03-568H, China Jushi Co., Ltd.;

[0039] Glass fiber B:S glass fiber, grade S-1 HM435TM-10-3.0, Taishan Glass Fiber Co., Ltd.;

[0040] Ethylene-maleic anhydride copolymer A: weight average molecular weight 10000, ZeMac E10, Vantrus, USA;

[0041] Ethylene-maleic anhydride copolymer B: weight average molecular weight 60,000, ZeMac E60, Vantrus, USA;

[0042] Ethylene-maleic anhydride copolymer C: weight average molecular weight 400,000, ZeMac E400, Vantrus, USA;

[0043] Heat stabilizer A: Spirophosphite 608, Chitai Technology Co., Ltd.;

[0044] Heat stabilizer B: Bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, PEP-36, Adico (China) Investment Co., Ltd.;

[0045] Heat stabilizer C: Tris(2,4-di-tert-butylphenyl) phosphite, RIANOX 168, Tianjin Lianlong New Material Co., Ltd.;

[0046] Heat stabilizer D: Copper salt, 8:1:1 KI / CUI / ZN STEARATE BLEND, AJAY Corporation;

[0047] Antioxidant: IRGANOX 1098, a hindered phenolic antioxidant; the same substance was used in parallel experiments.

[0048] Lubricant: TR044W, montan ester lubricant, is an ester-based lubricant; the same substance was used in parallel experiments.

[0049] The preparation method of the polyamide composite material in the embodiments and comparative examples of the present invention includes the following steps:

[0050] Weigh each component according to weight parts. Mix all components except glass fiber in a high-speed mixer for 3-10 minutes, then add them to the main feed hopper of a twin-screw extruder. Add glass fiber from the side feed hopper of the sixth screw section. After thorough plasticization and melting, extrude, stretch, cool, and pelletize to obtain the polyamide composite material. The twin-screw extruder has a screw speed of 500 rpm, a length-to-diameter ratio of 48:1, and the screw temperature of each section of the extruder is 160℃-250℃, with a die temperature of 220℃.

[0051] II. Performance Testing Methods

[0052] (1) Test method for mold deposits:

[0053] Using an injection molding machine equipped with a mold fouling collector, 200 molds were continuously injected at injection temperatures of 270℃, 265℃, 260℃, and 255℃. The mold fouling sample from the last collected mold was removed and weighed using an analytical balance to obtain the final mold fouling weight.

[0054] (2) Test method for notched impact strength of cantilever beam:

[0055] The ISO standard test strips are used in accordance with the ISO 180-2019 testing standard.

[0056] Table 1. Technical solutions and performance test results of the embodiments (unit: parts by weight)

[0057] Table 2 Comparative technical solutions and performance test results (unit: parts by weight)

[0058] Comparative Examples 1 to 4 all use a single variable compared to Example 2. Comparative Example 1 does not add ethylene-maleic anhydride copolymer, Comparative Example 2 adds too much ethylene-maleic anhydride copolymer, Comparative Example 3 does not use heat stabilizing agent, Comparative Example 4 adds too much heat stabilizing agent, and Comparative Example 5 uses other types of heat stabilizers. None of the above examples can achieve the goal of reducing mold fouling while maintaining a high notched impact strength.

[0059] Based on the test data of mold density and notched impact strength in Tables 1 and 2, the polyamide composite materials prepared in Examples 1-14 exhibit a notched impact strength of 6.1 kJ / m. 2 The above reduces mold fouling to below 0.3 mg. Materials with low mold fouling and high impact strength can meet the needs of industries such as automotive, electronics, energy storage, and connectors.

[0060] 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. A flame-retardant polyamide composite material, characterized in that, Based on parts by weight, it comprises the following components: The heat-stabilizing agent is a phosphite.

2. The flame-retardant polyamide composite material according to claim 1, characterized in that, The weight ratio of the ethylene-maleic anhydride copolymer to the heat stabilizer is (0.5-8):

1.

3. The flame-retardant polyamide composite material according to claim 1, characterized in that, The relative viscosity of the polyamide resin is 2.0 to 5.

1.

4. The flame-retardant polyamide composite material according to claim 1, characterized in that, The synergistic flame retardant is one or more of the following: melamine polyphosphate, melamine aluminum polyphosphate, melamine magnesium polyphosphate, melamine zinc polyphosphate, zinc borate, and magnesium hydroxide.

5. The flame-retardant polyamide composite material according to claim 1, characterized in that, The glass fiber is one or more of E glass fiber, A glass fiber, S glass fiber, D glass fiber, C glass fiber, and quartz glass fiber.

6. The flame-retardant polyamide composite material according to claim 1, characterized in that, The ethylene-maleic anhydride copolymer has a weight-average molecular weight of 8,000 to 70,000.

7. The flame-retardant polyamide composite material according to claim 1, characterized in that, The flame-retardant polyamide composite material further includes an antioxidant, wherein the antioxidant is present in parts by weight of 0 to 0.8 parts; The antioxidant is one or more of the following: hindered phenolic antioxidants, amine antioxidants, cuprous halide composite antioxidants, or antioxidants containing benzophenone functional groups.

8. The method for preparing the flame-retardant polyamide composite material according to any one of claims 1 to 7, characterized in that, Includes the following steps: Weigh each component according to the weight parts, mix all components except glass fiber in a high-speed mixer, and then add them to the main feed hopper of a twin-screw extruder. Add glass fiber from the side feed hopper of the sixth screw barrel. After fully plasticizing and melting, extrude, stretch, cool, and pelletize to obtain the flame-retardant polyamide composite material.

9. The application of the flame-retardant polyamide composite material according to any one of claims 1 to 7 in the fields of automobiles, electronics, energy storage, connectors and rail transportation.

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