High-temperature-resistant and high-toughness modified nylon composite material and preparation method thereof

Abstract

The invention provides a high-temperature-resistant and high-toughness modified nylon composite material and a preparation method thereof. The modified nylon composite material is prepared from the following components in parts by weight: 40 to 60 parts of PA6T, 20 to 30 parts of PA9T, 10 to 25 parts of maleic anhydride grafted compound, 5 to 10 parts of modified montmorillonite, 0.1 to 1 part of antioxidant and 3 to 15 parts of flame retardant. The prepared modified nylon composite material is high in toughness and good in high temperature resistance, is not easy to crack when being impacted or vibrated, and is not easy to deform under long-term thermal load; the flame retardant property is good, the safety is high, and the dimensional stability is strong.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composite materials, and in particular relates to a high-temperature-resistant, high-toughness modified nylon composite material and a preparation method thereof. Background Art

[0002] Nylon, also known as polyamide, has good comprehensive properties, including mechanical properties, heat resistance, wear resistance, chemical resistance and self-lubrication. It also has a low coefficient of friction and certain flame retardancy. It is currently widely used in electronics, LED lighting, automotive industry and other fields.

[0003] With technological advancements and the acceleration of industrialization, demand is growing for high-performance nylon materials, particularly those with strong toughness, high-temperature resistance, and excellent flame retardancy. For example, in high-end electronic devices, these materials must resist deformation during processing and installation. In automotive exterior components, such as body panels and hoods, excellent toughness and ductility are required to accommodate complex vehicle deformations. Highly flexible and ductile nylon materials are needed to ensure these components resist rupture in collisions, while also ensuring flame retardancy levels meet automotive safety requirements.

[0004] Therefore, how to provide a modified nylon composite material with high temperature resistance, high toughness and good flame retardancy is an urgent problem to be solved in the present invention. Summary of the Invention

[0005] The object of the present invention is to provide a high-temperature resistant, high-toughness modified nylon composite material and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, the present invention provides a high-temperature resistant, high-toughness modified nylon composite material and a preparation method thereof. The modified nylon composite material comprises the following components in parts by weight: 40-60 parts of PA6T, 20-30 parts of PA9T, 10-25 parts of a maleic anhydride grafted compound, 5-10 parts of modified montmorillonite, 0.1-1 part of an antioxidant, and 3-15 parts of a flame retardant;

[0007] The modified montmorillonite is 1-hexadecyl-2,3-dimethylimidazolium bromide modified sodium montmorillonite.

[0008] As a further improvement, the synthesis of the modified montmorillonite comprises the following steps:

[0009] (1) Add sodium montmorillonite to distilled water, heat in an oil bath at 50-80°C, adjust the pH to acidic, and stir to form a uniform emulsion;

[0010] (2) adding 1-hexadecyl-2,3-dimethylimidazolium bromide to distilled water, heating and stirring to dissolve, and then adding it to the emulsion obtained in step (1) and stirring to react. After the reaction is completed, standing and stratifying, removing the upper layer, collecting the lower layer precipitate, and post-processing to obtain modified montmorillonite.

[0011] As a further improvement, the added mass ratio of the 1-hexadecyl-2,3-dimethylimidazolium bromide to the sodium montmorillonite is 1.5-4:1.

[0012] As a further improvement, the maleic anhydride grafted compound is maleic anhydride grafted EPDM rubber.

[0013] As a further improvement, the method for preparing the maleic anhydride grafted compound comprises the following steps:

[0014] (1) dissolving maleic anhydride and p-phenylenediamine in an organic solvent respectively, then slowly adding p-phenylenediamine-organic solvent to maleic anhydride-organic solvent, stirring and mixing, filtering and collecting the solid, and drying to obtain intermediate 1;

[0015] (2) Under a nitrogen atmosphere, EPDM rubber and an organic solvent are placed in a flask, stirred and heated. After the EPDM rubber is completely dissolved, the intermediate 1 obtained in step (1) and the initiator are added, and the reaction is stirred for 1-5 hours. After the reaction is completed, post-processing is performed to obtain a maleic anhydride grafted compound.

[0016] As a further improvement, the mass ratio of the added amount of the maleic anhydride grafted compound to the modified montmorillonite is 2-5:1.

[0017] As a further improvement, the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant.

[0018] As a further improvement, preferably, the hindered phenol antioxidant is antioxidant 3114, and the phosphite antioxidant is antioxidant 168.

[0019] As a further improvement, the added mass ratio of the hindered phenol antioxidant to the phosphite antioxidant is 1-1.5:1.

[0020] As a further improvement, the flame retardant is a halogen-free phosphorus-nitrogen flame retardant, comprising at least one of ammonium polyphosphate, melamine polyphosphate, and piperazine pyrophosphate.

[0021] For environmental protection and better flame retardant effect, preferably, the halogen-free phosphorus-nitrogen flame retardant is melamine polyphosphate.

[0022] The present invention also provides a method for preparing a high-temperature resistant, high-toughness modified nylon composite material, comprising the following steps:

[0023] (1) Add PA6T, PA9T, maleic anhydride grafted compound, modified montmorillonite, antioxidant, and flame retardant into a mixer according to weight and stir evenly to obtain a premix;

[0024] (2) The premix is ​​added into a twin-screw extruder, melt-mixed, extruded and granulated to obtain a modified nylon composite material.

[0025] As a further improvement, during the granulation, the temperature of zone 1 of the twin-screw extruder is 260-280°C, the temperature of zone 2 is 255-275°C, the temperature of zone 3 is 250-260°C, the temperature of zone 4 is 240-250°C, and the screw speed is 200-350r / min.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a high-temperature-resistant, high-toughness modified nylon composite material and a preparation method thereof, so that the prepared modified nylon composite material has high impact strength, elongation at break and heat deformation temperature, indicating high toughness and good high-temperature resistance, is not prone to cracking when subjected to impact or vibration, and is not prone to deformation under long-term heat load; has a high flame retardant grade, indicating good flame retardant performance and high safety, and is halogen-free and environmentally friendly; has a low water absorption rate, indicating that the material has strong resistance to moisture permeability and strong dimensional stability. DETAILED DESCRIPTION

[0028] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples are illustrative of the present invention and are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0029] In the following examples, except for modified sodium montmorillonite, octadecyltrimethylammonium chloride modified sodium montmorillonite, and maleic anhydride grafted compound, the remaining compound monomers and related reagents used can be purchased from the market, among which sodium montmorillonite was purchased from Hebei Guanchuan New Material Technology Co., Ltd.; EPDM rubber was purchased from Dongguan Mingyuan Plastic Co., Ltd., model 3722P; melamine polyphosphate was purchased from Hubei Xinyuhong Biomedicine Technology Co., Ltd., item number xyh001.

[0030] The synthesis of modified montmorillonite includes the following steps:

[0031] (1) Add 5 g of sodium montmorillonite to 120 mL of distilled water, heat in an oil bath at 80°C, adjust the pH to 5 with 65% nitric acid, and stir to form a uniform emulsion.

[0032] (2) 10 g of 1-hexadecyl-2,3-dimethylimidazolium bromide was added to 30 mL of distilled water and stirred at 60° C. to dissolve the mixture. The mixture was then added to the emulsion obtained in step (1) and stirred for reaction for 5 h. After the reaction was completed, the mixture was allowed to stand for 12 h and separated into layers. The upper foam and liquid were removed, and the flocculent precipitate in the lower layer was collected. The precipitate was filtered and rinsed with a large amount of hot distilled water until no precipitate was formed in the filtrate when detected with an AgNO3 solution. The precipitate was filtered and vacuum dried at 80° C. to constant weight, ground into powder, and sieved through a 200-mesh sieve to obtain modified montmorillonite 1.

[0033] The synthesis of octadecyltrimethylammonium chloride modified sodium montmorillonite comprises the following steps:

[0034] (1) 40 g of sodium montmorillonite was added to 900 mL of deionized water, stirred for 30 min, and then allowed to stand for 5 h. The supernatant was then aspirated. 400 mL of the supernatant and 107 mL of a 1 mol / L Na2CO3 solution were added to a flask, stirred for 30 min, and allowed to stand overnight. The filter cake was then dried and ground into powder.

[0035] (2) Weigh 30 g of the powder obtained in step (1), add it to 150 mL of anhydrous ethanol, ultrasonically disperse it for 30 min, then place it in an 80°C water bath and stir and disperse it. After refluxing, add dropwise a solution obtained by mixing 5 g of octadecyltrimethylammonium chloride and 25 mL of anhydrous ethanol, continue stirring and refluxing for 3 h, and after the reaction is completed, cool it to room temperature, filter it and wash it with deionized water until no precipitate is generated in the filtrate detected by AgNO3 solution. The precipitate obtained by filtration is vacuum dried at 100°C to constant weight, ground into powder, and sieved through 200 mesh to obtain octadecyltrimethylammonium chloride modified sodium montmorillonite.

[0036] The synthesis of maleic anhydride grafted compounds comprises the following steps:

[0037] (1) 98 g of maleic anhydride and 54 g of p-phenylenediamine were dissolved in 200 mL of acetone, and then the p-phenylenediamine-acetone solution was slowly added to the maleic anhydride-acetone solution, stirred and mixed for 1 h, filtered and the solid was collected, and dried at 60° C. to obtain intermediate 1;

[0038] (2) Under a nitrogen atmosphere, 100 g of EPDM rubber and 300 mL of xylene were placed in a flask, stirred and heated to 110° C. After the EPDM rubber was completely dissolved, 15 g of the intermediate 1 obtained in step (1) and 2 g of benzoyl peroxide were added, and the mixture was stirred for 3 h. After the reaction was completed, 500 mL of ethylene glycol was added to the flask, the flocculent precipitate was filtered and repeatedly washed with ethylene glycol, and finally dried in vacuo at 70° C. to obtain a maleic anhydride grafted compound.

[0039] The preparation methods of Examples 1-4 and Comparative Examples 1-3 comprise the following steps:

[0040] (1) Add PA6T, PA9T, maleic anhydride grafted compound, modified montmorillonite, antioxidant, and flame retardant into a mixer according to weight and stir evenly to obtain a premix;

[0041] (2) The premix is ​​added into a twin-screw extruder, melt-mixed, extruded and granulated to obtain a modified nylon composite material, wherein the temperature of the first zone of the twin-screw extruder is 270°C, the temperature of the second zone is 260°C, the temperature of the third zone is 255°C, the temperature of the fourth zone is 250°C, and the screw speed is 260 r / min.

[0042] The components and contents used in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1 below:

[0043] Table 1

[0044]

[0045]

[0046] The modified nylon composite materials prepared in Examples 1-4 and Comparative Examples 1-3 were tested for notched impact strength, elongation at break, heat deformation temperature, flame retardancy, and water absorption. The specific testing methods are as follows:

[0047] Notched impact strength: The material's Charpy notched impact strength is tested according to the method in ISO 179. The test environment temperature is 25°C.

[0048] Elongation at break: Test the elongation at break of the material according to the method in ISO 527-1;

[0049] Heat distortion temperature: tested according to ISO 75, load 1.80MPa;

[0050] Flame retardant performance: vertical burning test according to UL 94, sample size 125×13×0.8mm;

[0051] Water absorption rate: Prepare a 125×13×1.6mm sample, bake it in an oven at 140℃ for 4 hours, then place the sample in water and boil it for 3 hours. After taking it out, let it dry naturally to remove the moisture on the surface of the sample. Then use a moisture tester to test the moisture content of the sample, which is the water absorption rate of the product.

[0052] The test results are shown in Table 2:

[0053] Table 2

[0054]

[0055]

[0056] From the test results of Example 3 and Comparative Examples 1-2 in Table 2, it can be seen that compared with the preparation of modified nylon composite materials using sodium montmorillonite directly or using sodium montmorillonite modified by octadecyltrimethylammonium chloride, the modified nylon composite materials prepared using the modified montmorillonite of the present invention have higher impact strength, elongation at break and heat deformation temperature, indicating that the modified nylon composite materials prepared by the present invention have high toughness and good high temperature resistance, are not easy to crack when subjected to impact or vibration, and are not easy to deform under long-term heat load; have a high flame retardant grade, indicating good flame retardant performance, high safety, and halogen-free flame retardancy and environmental friendliness; have a low water absorption rate, indicating that the material has strong resistance to moisture permeability and high dimensional stability.

[0057] From the test results of Example 3 and Comparative Example 3 in Table 2, it can be seen that compared with the use of octadecyltrimethylammonium chloride to modify sodium montmorillonite and the use of only hindered phenolic antioxidants as the antioxidant to participate in the preparation of the modified nylon composite material, the use of 1-hexadecyl-2,3-dimethylimidazolium bromide to modify sodium montmorillonite and the use of hindered phenolic antioxidants and phosphite antioxidants as the antioxidants to act synergistically, the prepared modified nylon composite material has higher impact strength, elongation at break and heat deformation temperature; and from the test results of Comparative Examples 2 and 3, it can be seen that when hindered phenolic antioxidants and phosphite antioxidants are used to act synergistically, the prepared modified nylon composite material has better performance, indicating that the coordinated use of antioxidants can improve the toughness and high temperature resistance of the material, and to a certain extent reduce water absorption and improve dimensional stability.

[0058] The test results of Examples 1-4 show that the modified nylon composite material prepared by the preparation method provided by the present invention has higher impact strength, elongation at break, and heat deformation temperature, indicating high toughness and good high temperature resistance. It also has a high flame retardant rating and low water absorption, indicating good flame retardancy, high safety, dimensional stability, and a wide range of applications. Furthermore, the test results of Examples 1 and 2-4 show that when the modified montmorillonite is sodium montmorillonite modified with 1-hexadecyl-2,3-dimethylimidazolium bromide, and the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant, the performance of the modified nylon composite material is even better. The test results of Examples 3 and 4 show that when a maleic anhydride grafted compound is used in combination with the modified montmorillonite, and the added mass ratio of the maleic anhydride grafted compound to the modified montmorillonite is within an appropriate range, the performance of the modified nylon composite material is even better.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature resistant, high-toughness modified nylon composite material, characterized in that: The modified nylon composite material comprises the following components in parts by weight: 40-60 parts of PA6T, 20-30 parts of PA9T, 10-25 parts of maleic anhydride grafted compound, 5-10 parts of modified montmorillonite, 0.1-1 parts of antioxidant, and 3-15 parts of flame retardant; The modified montmorillonite is 1-hexadecyl-2,3-dimethylimidazolium bromide modified sodium montmorillonite.

2. A high temperature resistant, high toughness modified nylon composite material according to claim 1, characterized in that: The synthesis of the modified montmorillonite comprises the following steps: (1) Add sodium montmorillonite to distilled water, heat in an oil bath at 50-80°C, adjust the pH to acidic, and stir to form a uniform emulsion; (2) adding 1-hexadecyl-2,3-dimethylimidazolium bromide to distilled water, heating and stirring to dissolve, and then adding it to the emulsion obtained in step (1) and stirring to react. After the reaction is completed, standing and stratifying, removing the upper layer, collecting the lower layer precipitate, and post-processing to obtain modified montmorillonite.

3. A high-temperature resistant, high-toughness modified nylon composite material according to claim 2, characterized in that: The added mass ratio of the 1-hexadecyl-2,3-dimethylimidazolium bromide to the sodium montmorillonite is 1.5-4:

1.

4. The high-temperature resistant, high-toughness modified nylon composite material according to claim 1, characterized in that: The maleic anhydride grafted compound is maleic anhydride grafted EPDM rubber.

5. The high-temperature resistant, high-toughness modified nylon composite material according to claim 4, characterized in that: The preparation method of the maleic anhydride grafted compound comprises the following steps: (1) dissolving maleic anhydride and p-phenylenediamine in an organic solvent respectively, then slowly adding p-phenylenediamine-organic solvent to maleic anhydride-organic solvent, stirring and mixing, filtering and collecting the solid, and drying to obtain intermediate 1; (2) Under a nitrogen atmosphere, EPDM rubber and an organic solvent are placed in a flask, stirred and heated. After the EPDM rubber is completely dissolved, the intermediate 1 obtained in step (1) and the initiator are added, and the reaction is stirred for 1-5 hours. After the reaction is completed, post-processing is performed to obtain a maleic anhydride grafted compound.

6. The high-temperature resistant, high-toughness modified nylon composite material according to claim 1, characterized in that: The mass ratio of the added amount of the maleic anhydride grafted compound to the modified montmorillonite is 2-5:

1.

7. The high-temperature resistant, high-toughness modified nylon composite material according to claim 1, characterized in that: The antioxidants are hindered phenol antioxidants and phosphite antioxidants.

8. The high-temperature resistant, high-toughness modified nylon composite material according to claim 7, characterized in that: The added mass ratio of the hindered phenol antioxidant to the phosphite antioxidant is 1-1.5:

1.

9. The high-temperature resistant, high-toughness modified nylon composite material according to claim 1, characterized in that: The flame retardant is a halogen-free phosphorus-nitrogen flame retardant, and includes at least one of ammonium polyphosphate, melamine polyphosphate, and piperazine pyrophosphate.

10. A method for preparing a high-temperature resistant, high-toughness modified nylon composite material according to any one of claims 1 to 9, comprising the following steps: (1) Add PA6T, PA9T, maleic anhydride grafted compound, modified montmorillonite, antioxidant, and flame retardant into a mixer according to weight and stir evenly to obtain a premix; (2) The premix is ​​added into a twin-screw extruder, melt-mixed, extruded and granulated to obtain a modified nylon composite material.

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