A semi-aromatic polyamide resin and composite material, and preparation method and application thereof

Abstract

The present invention discloses a semi-aromatic polyamide resin and a composite material thereof, as well as a preparation method and an application thereof, belonging to the technical field of polymer materials; the semi-aromatic polyamide resin provided by the present invention has a diamine unit, a diacid unit, and a capping structure derived from Formula 1; the molar ratio of the compound of Formula 1 to the diacid unit is (0.01-0.03):1; when the semi-aromatic polyamide resin prepared by the present invention is applied to the preparation of a semi-aromatic polyamide composite material, the obtained composite material has the characteristics of ultra-high fluidity, flame retardancy, high temperature resistance, and anti-foaming property, and can be applied to the preparation of parts for new energy, 5G communication, and electronics and electrical appliances, meeting the requirements of the SMT process; at the same time, the preparation method provided by the present invention is simple and is beneficial to actual production;#imgabs0#

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a semi-aromatic polyamide resin and composite material, and a preparation method and application thereof. Background Art

[0002] In recent years, with the high density and miniaturization of electronic products, the lead-free surface mount technology (SMT) has become an important assembly method. Its application requires components to withstand high temperatures of 250 - 280 °C. Traditional engineering plastics such as PA66 and PBT simply cannot meet this requirement, and high-temperature engineering plastics have emerged as the times require. Due to the advantages of semi-aromatic polyamide (PPA) such as high melting point, high heat distortion temperature, and high strength, it is widely used in the connector field.

[0003] Due to the miniaturization of connector products, extremely high requirements are placed on the fluidity of PPA materials. Generally speaking, the main methods to improve the fluidity of materials are as follows: One is to reduce the molecular weight of the resin, thereby reducing its viscosity to achieve high fluidity, such as CN 201910128425. However, this method is likely to reduce the thermal stability of the material, and a large amount of mold fouling is easily generated during continuous injection molding at high temperatures, and even bubbling phenomena occur during the SMT process. Another is to add a third or even fourth monomer to PPA to reduce the melting point of the material and achieve the effect of meeting high fluidity; but when the addition amount is small, the processing effect cannot be improved, and when the addition amount is high, it is likely to cause problems such as low melting point and poor thermal stability. There have even been attempts to add aliphatic nylon to the system and then improve the compatibility between high-temperature nylon and aliphatic nylon by adding a compatibilizer, such as CN201610892639. However, all these methods mentioned above will reduce the heat resistance of the material and even increase the water absorption rate of the material. Although the purpose of improving the processing performance is achieved, phenomena such as flow casting (caused by the large difference in processing temperatures between semi-aromatic and aliphatic) and bubbling (a large amount of gas is generated during high-temperature injection molding of aliphatic nylon) are likely to occur. There are also attempts to add hyperbranched lubricants and the like to improve the fluidity of the material, such as CN202110730705. However, the heat resistance of hyperbranched materials is relatively low and they are easily decomposed during the extrusion and processing of PPA, resulting in bubbling during the SMT process.

[0004] That is, in the prior art, although the fluidity of the material can be improved to a certain extent through various methods, it is inevitable that phenomena such as flow casting, bubbling, and poor heat resistance will occur in the material. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a semi-aromatic polyamide resin with ultra-high fluidity, resistance to reflow soldering blistering, and high heat resistance, and at the same time provide a semi-aromatic polyamide composite material that has ultra-high fluidity, resistance to reflow soldering blistering, and high heat resistance on the basis of flame retardancy, and a preparation method and application thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a semi-aromatic polyamide resin, the semi-aromatic polyamide resin having a diamine unit, a diacid unit, and an end-capping structure derived from Formula 1;

[0007]

[0008] Wherein, R1, R2 and R3 are each independently at least one of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and R1, R2 and R3 are not hydrogen atoms at the same time.

[0009] The semi-aromatic polyamide resin provided by the present invention can play a role in stretching the chain segments by introducing a specific end-capping group, specifically, introducing a branched benzoic acid compound as an end-capping agent, thereby achieving an ultra-high fluidity effect, and can meet the requirements of flame retardancy and high temperature resistance when it is subsequently applied to a semi-aromatic polyamide composite material, and has the characteristics of foaming resistance. The flame retardancy grade of the obtained semi-aromatic polyamide composite material is V-0, the fluidity is above 38 mm, the melting point is above 304.3°C, and no foaming occurs during the test process.

[0010] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the molar ratio of the compound of formula 1 to the diacid unit is (0.01-0.03):1.

[0011] Preferably, the molar ratio of the compound of formula 1 to the diacid unit is 0.03:1.

[0012] The inventors have found that when the molar ratio of the compound of formula 1 to the diacid unit is further selected to be (0.01-0.03):1, especially when the molar ratio of the compound of formula 1 to the diacid unit is further preferably 0.03:1, when it is applied to the subsequent preparation of composite materials, the overall effect of the obtained composite material is more excellent.

[0013] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the amine-to-carboxyl ratio of the diamine unit to the diacid unit is (1.005-1.08):1.

[0014] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the alkyl group having 1-6 carbon atoms is at least one of methyl, ethyl, n-butyl, tert-butyl, n-pentyl, and isopentyl; the alkoxy group having 1-6 carbon atoms is at least one of methoxy, ethoxy, propoxy, and butoxy.

[0015] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the compound represented by Formula 1 is a compound represented by the following structural formulas Ⅰ-Ⅴ,

[0016]

[0017] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the compound represented by Formula 1 is a compound represented by Structural Formula III and Structural Formula IV.

[0018] The inventors have found that when the structural formula of the end-capping agent is further preferred to be a compound represented by structural formula III and structural formula IV, it can better play the role of stretching the chain segments, thereby achieving better fluidity; and thus, when the obtained semi-aromatic polyamide resin is applied to the subsequent preparation of a semi-aromatic polyamide composite material, the comprehensive performance of the obtained composite material is better, specifically, the flowability of the obtained composite material is above 58 mm.

[0019] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the diamine unit is at least one monomer of an aliphatic diamine having a carbon number ≥ 9, the diacid unit is 45-100% of an aromatic dicarboxylic acid and 0-55% of an aliphatic dicarboxylic acid; the aliphatic diamine is selected from 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 5- The aromatic dicarboxylic acid is selected from at least one of terephthalic acid, isophthalic acid, 2-methylterephthalic acid, 2,5-dichloroterephthalic acid, 2,6-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, and 2,2'-biphenyl dicarboxylic acid; the aliphatic dicarboxylic acid is selected from at least one of 1,4-succinic acid, 1,6-hexane dicarboxylic acid, 1,8-octanedioic acid, 1,9-nonane diamine, 1,10-decanedioic acid, 1,11-undecanedioic acid, and 1,12-dodecane dioic acid.

[0020] Preferably, the diamine unit is at least one monomer of an aliphatic diamine having 9 to 12 carbon atoms.

[0021] As a preferred embodiment of the semi-aromatic polyamide resin of the present invention, the aliphatic diamine is selected from at least one of 1,9-nonanediamine, 1,10-decanediamine, and 1,12-dodecanediamine, and the aromatic dicarboxylic acid is selected from at least one of terephthalic acid and isophthalic acid.

[0022] Preferably, the aliphatic diamine is selected from at least one of 1,10-decanediamine and 1,12-dodecanediamine, and the aromatic dicarboxylic acid is selected from terephthalic acid.

[0023] The inventors have found through research that when the aliphatic diamine and the aromatic dicarboxylic acid are further preferably the above substances, the obtained resin has more excellent fluidity; and then when the obtained semi-aromatic polyamide resin is applied to the preparation of the subsequent semi-aromatic polyamide composite material, the comprehensive performance of the obtained composite material is more excellent.

[0024] In addition, the present invention also provides a preparation method of the semi-aromatic polyamide resin, and the preparation method includes the following steps:

[0025] (1) Add the metered diamine unit, diacid unit, end-capping agent, antioxidant, and catalyst to an autoclave, and carry out pressure heating polymerization under the protection of an inert gas to obtain a prepolymer;

[0026] (2) Solid-phase viscosity increase the prepolymer to obtain a semi-aromatic polyamide resin.

[0027] As a preferred embodiment of the preparation method of the present invention, in the step (1), the addition amount of the antioxidant is 1-4‰ of the total mass of the substances, and the addition amount of the catalyst is 0.5-2‰ of the total mass of the substances.

[0028] Preferably, the antioxidant is antioxidant 1098, and the catalyst is sodium hypophosphite catalyst.

[0029] As a preferred embodiment of the preparation method of the present invention, in the step (1), the temperature of the polymerization reaction is 230-240 °C, the pressure of the polymerization reaction is 2.9-3.1 MPa, and the constant pressure of 2.9-3.1 MPa is maintained by removing the formed water during the polymerization reaction.

[0030] As a preferred embodiment of the preparation method of the present invention, in the step (2), the temperature of the solid-phase viscosity increase is 240-250 °C, and the time is 1-3 h.

[0031] In addition, the present invention also provides a semi-aromatic polyamide composite material, and the semi-aromatic polyamide composite material comprises the following components in parts by mass: 35-50 parts of the semi-aromatic polyamide resin, 12-22 parts of a flame retardant, and 15-50 parts of a reinforcing material; the flame retardant is at least one of a phosphinate flame retardant and a dialkyl phosphinate flame retardant.

[0032] The inventors have found through research that using the semi-aromatic polyamide resin provided by the present invention as a component to prepare a semi-aromatic polyamide resin composite material can endow the obtained composite material with ultra-high fluidity, flame retardancy, high temperature resistance, and excellent anti-bubbling performance.

[0033] As a preferred embodiment of the semi-aromatic polyamide composite material of the present invention, the semi-aromatic polyamide composite material comprises the following components in parts by mass: 40 parts of the semi-aromatic polyamide resin, 15-20 parts of the flame retardant, and 20-30 parts of the reinforcing material.

[0034] The inventors have found through research that when the addition amounts of the components are further preferably within the above ranges, the comprehensive performance of the obtained composite material is more excellent.

[0035] As a preferred embodiment of the semi-aromatic polyamide composite material of the present invention, the reinforcing material is at least one of glass fiber, carbon fiber, asbestos fiber, wollastonite fiber, ceramic fiber, potassium titanate whisker, basic magnesium sulfate whisker, silicon carbide whisker, aluminum borate whisker, silicon dioxide, aluminum silicate, silica, calcium carbonate, titanium dioxide, talc, wollastonite, diatomite, clay, kaolin, spherical glass, mica, and gypsum.

[0036] Preferably, the reinforcing material is glass fiber; the inventors have found through research that when the reinforcing material is further preferably glass fiber, the comprehensive performance of the obtained product is more excellent.

[0037] In addition, the present invention also provides a method for preparing the semi-aromatic polyamide composite material, and the preparation method comprises the following steps: mixing the raw materials and then performing melt extrusion, cooling, air drying, and pelletizing to obtain the semi-aromatic polyamide composite material.

[0038] As a preferred embodiment of the preparation method of the present invention, the specific preparation process is as follows: adding the semi-aromatic polyamide resin into an extruder from the main feed port, adding the reinforcing material into the extruder from the first side feed port, adding the flame retardant into the extruder from the second side feed port, and after adding, performing melt blending at 250-350 °C, and then cooling, air drying, and pelletizing to obtain the semi-aromatic polyamide composite material.

[0039] In addition, the present invention also provides an application of the semi-aromatic polyamide composite material in the preparation of new energy, 5G communication and electronic and electrical parts. Exemplarily, the semi-aromatic polyamide composite material of the present invention is applied to DDR connectors and high-voltage connectors.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] A semi-aromatic polyamide resin provided by the present invention can achieve the effect of stretching chain segments by introducing a branched benzoic acid compound as a capping agent, thereby achieving an ultra-high fluidity effect, so that when the obtained semi-aromatic polyamide resin is applied to a subsequent semi-aromatic polyamide resin composite material, the obtained composite material can also have ultra-high fluidity and meet the requirements of flame retardancy and high temperature resistance, and has the characteristics of foaming resistance; specifically, the flame retardancy grade of the obtained semi-aromatic polyamide composite material is V-0, the fluidity is above 38 mm, the melting point is above 304.3° C., and no serious deformation occurs during the test process; therefore, the obtained semi-aromatic polyamide composite material can be used in the preparation of parts of electronic, electrical or electrical products, and meets the requirements of the SMT process; at the same time, the preparation method provided by the present invention is simple and is conducive to actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of thin-walled elongated strips used in the flowability test process in the effect example;

[0043] Figure 2 This is a diagram showing the situation in which no foaming occurs in the foaming test in the effect example;

[0044] Figure 3 This is a diagram showing the foaming condition in the foaming test in the effect example;

[0045] Figure 4 This is a diagram showing the severe deformation during the foaming test in the effect example. DETAILED DESCRIPTION

[0046] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0047] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0048] PA66: PA66 EPR24, Shenma Group, China;

[0049] Flame retardant 1: aluminum diethylphosphinate, commercially available;

[0050] Flame retardant 2: zinc diethylphosphinate, commercially available;

[0051] Flame retardant 3: Melamine polyphosphate, commercially available;

[0052] Reinforcing material: Glass fiber, commercially available.

[0053] Example 1

[0054] The embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-1, whose diamine unit is 1,10-decanediamine, diacid unit is terephthalic acid, and end-capping agent is the compound shown in Structural Formula Ⅰ;

[0055] The preparation method of the PA10T-1 is as follows: Weigh the materials (the amine-carboxylic acid ratio of the diamine unit and diacid unit is 1.05, and the dosage of the end-capping agent is 0.03 times the molar amount of the diacid unit), add them to a 20L autoclave, and fixedly add 2‰ (total mass of substances) of antioxidant 1098 and 1‰ (total mass of substances) of sodium hypophosphite catalyst. After the feeding is completed, evacuate the air, fill with nitrogen to displace the gas, then heat to the predetermined temperature of 235 °C, and maintain a constant pressure of 3.0 MPa by removing the formed water; after the reaction is completed, release the pressure to atmospheric pressure to obtain a prepolymer; the prepolymer is solid-phase viscosity-increased at 245 °C in a rotary drum, and PA10T-1 is obtained after 2 hours of viscosity increase.

[0056] Example 2

[0057] The embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-2, whose diamine unit is 1,10-decanediamine, diacid unit is terephthalic acid, and end-capping agent is the compound shown in Structural Formula Ⅱ. The preparation method of the PA10T-2 is the same as that of Example 1.

[0058] Example 3

[0059] The embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-3, whose diamine unit is 1,10-decanediamine, diacid unit is terephthalic acid, and end-capping agent is the compound shown in Structural Formula Ⅲ. The preparation method of the PA10T-3 is the same as that of Example 1.

[0060] Example 4

[0061] The embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-4, whose diamine unit is 1,10-decanediamine, diacid unit is terephthalic acid, and end-capping agent is the compound shown in Structural Formula Ⅳ. The preparation method of the PA10T-4 is the same as that of Example 1.

[0062] Example 5

[0063] An embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-5, wherein the diamine unit is 1,10-decanediamine, the diacid unit is terephthalic acid, and the end-capping agent is the compound shown in Structural Formula V. The preparation method of the PA10T-5 is the same as that of Example 1.

[0064] Example 6

[0065] An embodiment of the present invention provides a semi-aromatic polyamide resin PA12T, wherein the diamine unit is 1,12-dodecanediamine, the diacid unit is terephthalic acid, and the end-capping agent is the compound shown in Structural Formula IV. The preparation method of the PA12T is the same as that of Example 1.

[0066] Example 7

[0067] An embodiment of the present invention provides a semi-aromatic polyamide resin PA6T / 66, wherein the diamine unit is hexamethylenediamine, the diacid units are adipic acid and terephthalic acid (the molar ratio of terephthalic acid to adipic acid is 60:40), and the end-capping agent is the compound shown in Structural Formula IV. The preparation method of the PA6T / 66 is the same as that of Example 1.

[0068] Example 8

[0069] An embodiment of the present invention provides a semi-aromatic polyamide resin PA9T, wherein the diamine unit is 1,9-nonanediamine, the diacid unit is terephthalic acid, and the end-capping agent is the compound shown in Structural Formula IV. The preparation method of the PA9T is the same as that of Example 1.

[0070] Example 9

[0071] An embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-7. The only difference between this embodiment of the present invention and Example 1 is that in the preparation of the added semi-aromatic polyamide resin, the amount of the end-capping agent used is 0.01 times the molar amount of the diacid unit.

[0072] Example 10

[0073] An embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-8. The only difference between this embodiment of the present invention and Example 1 is that in the preparation of the added semi-aromatic polyamide resin, the amount of the end-capping agent used is 0.02 times the molar amount of the diacid unit.

[0074] Example 11

[0075] An embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-9. The only difference between this embodiment of the present invention and Example 1 is that in the preparation of the added semi-aromatic polyamide resin, the amount of the end-capping agent used is 0.008 times the molar amount of the diacid unit.

[0076] Example 12

[0077] An embodiment of the present invention provides a semi-aromatic polyamide resin PA10T-10. The only difference between the embodiment of the present invention and Example 1 is that during the preparation of the added semi-aromatic polyamide resin, the amount of the end-capping agent is 0.04 times the molar amount of the diacid unit.

[0078] Comparative Example 1

[0079] The comparative example of the present invention provides a semi-aromatic polyamide resin PA10T-6, the diamine unit of which is 1,10-decanediamine, the diacid unit is terephthalic acid, and the end-capping agent is benzoic acid. The preparation method of the PA10T-6 is the same as that of Example 1.

[0080] Examples 13-29 and Comparative Examples 2-6

[0081] Examples 13-29 of the present invention and Comparative Examples 2-6 provide a semi-aromatic polyamide composite material, and the component contents of the semi-aromatic polyamide composite material are shown in Tables 1-2;

[0082] Table 1

[0083]

[0084]

[0085] Table 2

[0086]

[0087] The preparation method of the semi-aromatic polyamide composite material provided by Examples 13-29 and Comparative Examples 2-6 is as follows:

[0088] The semi-aromatic polyamide resin is added to the extruder from the main feed port, the reinforcing material is added to the extruder from the first side feed port, and the flame retardant is added to the extruder from the second side feed port. After adding, melt blending is carried out at 250-350 °C, and then it is cooled, air-dried, and pelletized to obtain the semi-aromatic polyamide composite material.

[0089] Effect Example

[0090] This effect example tests the performance of the semi-aromatic polyamide composite materials prepared in Examples 13-29 and Comparative Examples 2-6; specifically, the following tests are included:

[0091] 1. Flame retardancy test: The semi-aromatic polyamide composite material is dried at 120 °C for 4 h and then tested according to standard injection molding. The flame retardancy of a specimen with a thickness of 0.8 mm is tested according to the UL-94 standard;

[0092] 2. Flowability test: Granules are molded using an injection molding machine equipped with a thin-walled elongated strip mold at a barrel temperature of melting point + 20 °C, a mold temperature of 120 °C, an injection pressure of 90 MPa, and a shooting speed of 75% to obtain an elongated strip sample with a wall thickness of 0.5 mm. The length of the sample is read to observe the flowability of the polymer composition. The thin-walled elongated strip is as Figure 1 shown;

[0093] 3. Foaming property test: Inject a 60 * 60 * 1.0 mm square plate. Place the square plate in a high-temperature and high-humidity condition of 85 °C / 85% R.H. for rapid humidity adjustment for 168 h. Place the test piece in the SER-710A equipment of Nitto Denko Technology (Shenzhen) Co., Ltd. Heat it from room temperature to 150 °C in 45 seconds in air, then heat it from 150 °C to 200 °C in 135 seconds, and then heat it to 260 °C at a maximum temperature rise rate of 3 °C / s, where the time above 255 °C is 20 - 40 s, and then cool it to room temperature at a maximum temperature drop rate of 6 °C / s. Take out the test piece and observe whether there is foaming on the test piece ([ Figure 2 is the case of no foaming, Figure 3 is the case of foaming, Figure 4 is the case of severe deformation);

[0094] 4. Melting point test: According to the ISO 11357-1 / -3-2011 standard, place the sample in a Netzsch DSC214. Under a nitrogen atmosphere, heat it from room temperature to melting point + 20 °C at a heating rate of 10 °C / min, then cool it to room temperature at 10 °C / min, and then heat it to melting point + 20 °C at 10 °C / min. Take the second heating data.

[0095] The test results are shown in Table 3;

[0096] Table 3

[0097]

[0098]

[0099] It can be seen from the data in Table 3 that when the technical solution of the present invention is adopted, the obtained semi-aromatic polyamide composite material has ultra-high flowability, high heat resistance, and foam resistance in addition to flame retardancy. Specifically, the obtained flowability data is above 38 mm, the obtained melting point is above 304.3 °C, and the obtained product will not have severe deformation in the foam resistance test;

[0100] It can be seen from Examples 13-17 and Comparative Examples 2-3 that the added amounts of the semi-aromatic polyamide resin, flame retardant and reinforcing material will affect the performance of the product. When the added amount of the semi-aromatic polyamide resin is further preferably 40 parts, the flame retardant is 15-20 parts, and the reinforcing material is 20-30 parts, the comprehensive performance of the obtained product is more excellent. Specifically, the fluidity of the obtained product is above 46 mm, and the melting point is above 314.3 °C; while when the added amounts of the components are not within the ranges given in the present invention, the comprehensive performance of the obtained product shows an obvious downward trend. For example, when the added amount of the flame retardant in Comparative Example 2 is too small, the flame retardant performance of the obtained product is significantly reduced, only reaching V-2 and not meeting the requirement; for example, when the added amount of the reinforcing material in Comparative Example 3 is too small, although the fluidity and melting point of the obtained product are relatively good, the foam resistance of the product is significantly reduced, and the test result shows that foaming will occur;

[0101] It can be seen from Example 13, Example 18 and Comparative Example 4 that the selection of the flame retardant will also affect the performance of the product. When the flame retardant selected is not the one provided by the present invention, the comprehensive performance of the obtained product is significantly reduced, manifested as a significant reduction in the flame retardant performance, only reaching V-2 and not meeting the requirement;

[0102] It can be seen from Example 13, Examples 19-22 and Comparative Example 5 that when the capping agent provided by the present invention is used as the capping group, the comprehensive performance of the obtained product is excellent. Especially when the compounds shown in Structural Formula III and Structural Formula IV are further selected, the comprehensive performance of the obtained product is more excellent. Specifically, the fluidity of the obtained product is above 58 mm, and the melting point is above 312.3 °C; while when benzoic acid is used as the capping agent, the fluidity of the obtained product is significantly reduced, and compared with Example 11, the reduction amplitude reaches 25.53%;

[0103] It can be seen from Example 21 and Examples 23-25 that the selection of the diamine unit and diacid unit in the semi-aromatic polyamide resin will also affect the performance of the product. When the semi-aromatic polyamide resin is further selected as PA10T, PA9T and PA12T, the comprehensive performance of the obtained product is more excellent and no foaming occurs in the foam resistance test; especially when the semi-aromatic polyamide resin is further selected as PA10T, the comprehensive performance is more excellent, the obtained fluidity can reach 63 mm, and the melting point is 312.3 °C;

[0104] It can be seen from the examples and Comparative Example 6 that compared with traditional engineering plastics, the product obtained by the present invention has good flame retardancy and fluidity, and will not produce serious deformation during the foam resistance test;

[0105] As can be seen from Example 13 and Examples 26-29, during the preparation of the semi-aromatic polyamide resin, the dosage of the end-capping agent also has an impact on the properties of the product.

[0106] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A semi-aromatic polyamide composite material, characterized in that, The semi-aromatic polyamide composite material comprises the following components in parts by mass: 35-50 parts of semi-aromatic polyamide resin, 12-22 parts of flame retardant, and 15-50 parts of reinforcing material; The flame retardant is at least one of hypophosphite flame retardant and dialkyl hypophosphite flame retardant; The semi-aromatic polyamide resin has a terminal structure derived from diamine units, diacid units, and compounds shown in Structural Formula III and Structural Formula IV as follows; ； The molar ratio of the terminal structure to the diacid unit is (0.01-0.03):1; The reinforcing material is glass fiber.

2. The semi-aromatic polyamide composite material according to claim 1, wherein The diamine unit is at least one of aliphatic diamines with ≥9 carbon atoms, and the diacid unit is 45-100% aromatic dicarboxylic acid and 0-55% aliphatic dicarboxylic acid; The aliphatic diamine is selected from at least one of 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, the aromatic dicarboxylic acid is selected from at least one of terephthalic acid, isophthalic acid, 2-methylterephthalic acid, 2,5-dichloroterephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyldicarboxylic acid, and the aliphatic dicarboxylic acid is selected from at least one of 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,12-dodecanedioic acid.

3. The semi-aromatic polyamide composite material according to claim 1, characterized in that The preparation method of the semi-aromatic polyamide resin comprises the following steps: (1) Add the metered diamine units, diacid units, end-capping agent, antioxidant, and catalyst into an autoclave, and carry out pressure heating polymerization under the protection of inert gas to obtain a prepolymer; (2) Solid-phase viscosity increase the prepolymer to obtain the semi-aromatic polyamide resin.

4. The semi-aromatic polyamide composite material according to claim 1, characterized in that, The semi-aromatic polyamide composite material comprises the following components in parts by mass: 40 parts of semi-aromatic polyamide resin, 15-20 parts of flame retardant, and 20-30 parts of reinforcing material.

5. The preparation method of the semi-aromatic polyamide composite material according to claim 1 or 4, characterized in that, The preparation method comprises the following steps: Mix the raw materials, then carry out melt extrusion, cooling, air drying, and pelletizing to obtain the semi-aromatic polyamide composite material.

6. The application of the semi-aromatic polyamide composite material according to claim 1 or 4 in the preparation of parts for new energy, 5G communication, and electronic and electrical appliances.

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