A high-temperature resistant polyphthalamide composite material for LED lamp beads and its preparation method

Abstract

The present invention provides a high-temperature resistant polyphthalamide composite material for LED lamp beads and a preparation method thereof, relating to the field of polymer material technology. The composite material comprises the following components, by mass percentage: 45-65% polyphthalamide, 35-55% silicon nitride, 0.1-2% compatibilizer, 0.2-0.6% antioxidant, 0.2-0.4% lubricant, and 0.3-0.5% nucleating agent. The present invention blends β-silicon nitride with polyphthalamide, utilizing the synergistic effect between PPA and β-silicon nitride, which have different structures and thermal conductivities: the added β-silicon nitride forms a cubic structure within the PPA, thereby comprehensively enhancing the material's rigidity, allowing the material to absorb a large amount of external force simultaneously, and effectively improving the material's high-temperature resistance and thermal conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a high-temperature resistant polyphthalamide composite material for LED lamp beads and a preparation method thereof. Background Art

[0002] Polyphthalamide (PPA) is a semi-aromatic polyamide primarily synthesized from isophthalic acid or terephthalic acid. It is a semi-crystalline thermoplastic functional material. PPA is currently the most commercially valuable of the semi-aromatic polyamides. The successful production of high-temperature-resistant PPA has offset the cost-effectiveness and functionality differences between engineering plastics and specialty polymers. Compared to some fully aromatic polyamides, PPA is relatively simple to process, making it easier to blow mold, injection mold, and extrusion mold. Furthermore, PPA's mechanical properties, thermal conductivity, heat resistance, and chemical resistance surpass those of aliphatic polyamides, demonstrating excellent thermal, electrical, physical, and chemical resistance. This makes PPA composites promising for broad application in fields such as electronics and mechanical engineering.

[0003] Existing technologies, PPA, after being modified with carbon fiber, glass fiber, and other fillers, can achieve exceptional mechanical properties, maintaining these exceptional properties over extended periods of time and temperature. Consequently, PPA has become a superior engineering plastic capable of replacing metals, finding widespread application in various industries, including automotive, electrical appliances, and electronics.

[0004] However, the research on the processing and modification of traditional PPA in China is still incomplete and immature, and the thermal conductivity and heat resistance of PPA need to be improved or enhanced. Therefore, it is urgent to conduct research on the modification of the thermal conductivity and heat resistance of high-temperature resistant PPA. Summary of the Invention

[0005] The object of the present invention is to provide a high-temperature resistant polyphthalamide composite material for LED lamp beads and a preparation method thereof. By blending β-silicon nitride with polyphthalamide, the synergistic effect between PPA and β-silicon nitride materials with different structures and thermal conductivities is utilized: the added β-silicon nitride forms a cubic structure inside the PPA, thereby comprehensively enhancing the stiffness of the material and enabling the material to absorb a large amount of external force at the same time; and the cubic structure formed by the β-silicon nitride inside the PPA can effectively resist the slight vertical movement of the molecules inside the material under high temperature conditions, greatly delaying the movement of the molecules inside the material and effectively improving the high-temperature resistance of the material; and the high thermal conductivity of β-silicon nitride can significantly improve the thermal conductivity coefficient of the material.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a high-temperature resistant polyphthalamide composite material for LED lamp beads, which comprises the following components by mass percentage:

[0008] Polyphthalamide 45-65%, silicon nitride 35-55%, compatibilizer 0.1-2%, antioxidant 0.2-0.6%, lubricant 0.2-0.4% and nucleating agent 0.3-0.5%.

[0009] Furthermore, based on the above technical solution of the present invention, the silicon nitride is β-silicon nitride;

[0010] And / or, the β-silicon nitride is in powder form with a particle size of ≤50 μm.

[0011] And / or, the β-silicon nitride powder is synthesized by self-propagating high temperature synthesis.

[0012] Furthermore, based on the above technical solution of the present invention, the compatibilizer is a polymer containing maleic anhydride grafts;

[0013] And / or, the polymer containing maleic anhydride grafts includes one or more of maleic anhydride grafted polyolefins, maleic anhydride grafted polyesters, maleic anhydride grafted polyethers, and maleic anhydride grafted polyamides.

[0014] Furthermore, based on the above technical solution of the present invention, the antioxidant is a compound containing a phenol group;

[0015] And / or, the compound containing a phenol group includes one or more of butylated hydroxyanisole, di-tert-butylated p-cresol, tert-butylated hydroxyanisole, and propyl gallate.

[0016] Furthermore, based on the above technical solution of the present invention, the lubricant is one or more of paraffin wax, polyethylene wax, polypropylene wax, polysiloxane, and silicone powder.

[0017] Furthermore, based on the above technical solution of the present invention, the nucleating agent is a sodium salt of a long carbon chain linear saturated carboxylic acid or a calcium salt of a long carbon chain linear saturated carboxylic acid.

[0018] Furthermore, based on the above technical solution of the present invention, the long carbon chain linear saturated carboxylic acid sodium salt includes one or more of sodium laurate, sodium stearate, sodium oleate, and sodium myristate;

[0019] And / or, the long carbon chain linear saturated carboxylic acid calcium salt includes one or more of TMN-102, calcium stearate, and calcium montanate.

[0020] The present invention also provides a method for preparing the high-temperature resistant polyphthalamide composite material for LED lamp beads, comprising the following steps:

[0021] S1: drying the raw materials;

[0022] S2: Place the dried raw materials in a blender and mix them evenly;

[0023] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder and extruded into granules.

[0024] Furthermore, based on the above technical solution of the present invention, in step S1, the drying condition is drying at 100-120° C. for 4-6 hours;

[0025] And / or, in step S2, the stirring time is 10-20 minutes.

[0026] Furthermore, based on the above technical solution of the present invention, the setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250-270°C, the temperature of zone 2 is 260-280°C, the temperature of zone 3 is 270-290°C, the temperature of zone 4 is 280-300°C, the temperature of zone 5 is 290-310°C, and the head temperature is 300-320°C; the screw speed is controlled at 220-350r / min, the conveying time of the mixture in the screw is 3-5min, and the pressure is 12-20Pa.

[0027] The present invention provides a high-temperature resistant polyphthalamide composite material for LED lamp beads and a preparation method thereof, which has the following beneficial effects:

[0028] 1. The present invention blends β-silicon nitride with polyphthalamide. The high content of β-silicon nitride is randomly dispersed within the material matrix, facilitating overlap with the matrix structure. This creates a synergistic effect between the PPA and β-silicon nitride materials, which differ in structure and thermal conductivity. The added β-silicon nitride forms a cubic structure within the PPA, thereby enhancing the material's stiffness and allowing it to absorb a wide range of external forces.

[0029] 2. The present invention blends β-silicon nitride with polyphthalamide. The cubic structure formed by β-silicon nitride inside PPA can effectively resist the slight vertical movement of the molecules inside the material under high temperature conditions, greatly delaying the movement of the molecules inside the material and effectively improving the high temperature resistance of the material.

[0030] 3. The present invention uses a phenolic compound as an antioxidant. The hydroxyl groups in the phenolic compound react with the amine groups in PPA to form a stable phenolamine, which not only improves the antioxidant properties of the composite material but also effectively enhances its flame retardancy. Furthermore, the antioxidant acts synergistically with β-silicon nitride, leveraging the high thermal conductivity of β-silicon nitride to increase the thermal conductivity of the material, thereby further improving the flame retardancy of the composite material. This avoids incompatibility between the flame retardant and polyphthalamide, which could affect the performance of the composite material.

[0031] 4. The present invention uses a polymer containing maleic anhydride grafts as a compatibilizer, which can effectively improve the adhesion and compatibility of the material and has good binding properties with polar polymers (such as nylon, polyester, epoxy resin, etc.).

[0032] 5. The high-temperature resistant polyphthalamide composite material for LED lamp beads provided by the present invention has a tensile strength of 160-200 MPa, a flexural strength of 282-320 MPa, a thermal conductivity of 2.9-3.7 W / (m·k), and a heat deformation temperature of 260-280°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a photo of an LED lamp bead prepared from the composite material provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The process parameters for which specific conditions are not specified in the following examples are generally in accordance with conventional conditions.

[0036] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0037] According to a first aspect of the present invention, there is provided a high-temperature resistant polyphthalamide composite material for LED lamp beads, comprising the following components by mass percentage:

[0038] Polyphthalamide 45-65%, silicon nitride 35-55%, compatibilizer 0.1-2%, antioxidant 0.2-0.6%, lubricant 0.2-0.4% and nucleating agent 0.3-0.5%.

[0039] As an optional embodiment of the present invention, the silicon nitride is β-silicon nitride;

[0040] And / or, the β-silicon nitride is in powder form with a particle size of ≤50 μm.

[0041] And / or, the β-silicon nitride powder is synthesized by self-propagating high temperature synthesis, see Wang Huabin et al. "Growth Mechanism of Silicon Nitride by Self-propagating High Temperature Synthesis".

[0042] Specifically, the present invention blends β-silicon nitride with polyphthalamide. This is because β-silicon nitride is a material with a cubic crystal structure. A high content of β-silicon nitride is randomly dispersed within the material matrix, which is conducive to overlapping with the structure of the matrix material. At this time, a certain synergistic effect is generated between PPA and β-silicon nitride, which have different structures and thermal conductivities. The added β-silicon nitride forms a cubic structure within the PPA, thereby comprehensively enhancing the rigidity of the material and allowing the material to absorb a large amount of external force simultaneously. Moreover, the cubic structure formed by β-silicon nitride within the PPA can effectively resist the slight vertical movement of the molecules within the material under high temperature conditions, greatly delaying the movement of the molecules within the material and effectively improving the material's high-temperature resistance.

[0043] Both α-silicon nitride and β-silicon nitride are hexagonal crystals, but α-silicon nitride is equiaxed while β-silicon nitride is rod-shaped. This difference in crystal structure leads to different material properties. In terms of mechanical properties, α-silicon nitride has higher hardness than β-silicon nitride crystals, but the rod-shaped β-silicon nitride is more conducive to crack deflection and grain extraction, increasing crack propagation resistance and possessing higher toughness and strength. Furthermore, the thermal conductivity of silicon nitride is significantly affected by its crystal form, so the thermal conductivity of β-silicon nitride is much higher than that of α-silicon nitride.

[0044] Therefore, the selective addition of β-silicon nitride into the high-temperature resistant polyphthalamide composite material for LED lamp beads of the present invention can effectively improve the strength, thermal conductivity and high-temperature resistance of the composite material.

[0045] As an optional embodiment of the present invention, the compatibilizer is a polymer containing maleic anhydride grafts;

[0046] And / or, the polymer containing maleic anhydride grafts includes one or more of maleic anhydride grafted polyolefins, maleic anhydride grafted polyesters, maleic anhydride grafted polyethers, and maleic anhydride grafted polyamides.

[0047] Specifically, the present invention uses a polymer containing maleic anhydride grafts as a compatibilizer. The polymer containing maleic anhydride grafts is generally composed of a main chain and multiple side chains. This structure enables the grafted polymer to act as a bridge between different polymers, thereby improving the interfacial compatibility between two or more polymers and reducing phase separation at the interface. In addition, the polymer containing maleic anhydride grafts contains polar carboxyl (-COOH) functional groups, which enable it to form hydrogen bonds or other interactions with polar polymers (such as nylon, polyester, epoxy resin, etc.), thereby improving the adhesion and compatibility of the material.

[0048] As an optional embodiment of the present invention, the antioxidant is a compound containing a phenol group;

[0049] And / or, the compound containing a phenolic group includes one or more of butylated hydroxyanisole (BHA), di-tert-butylated hydroxyanisole (BHT), tert-butylated hydroxyanisole (TBHQ), and propyl gallate (PG).

[0050] Specifically, the traditional method of preparing PPA usually requires the addition of flame retardants to improve the fire resistance of the material. However, some flame retardants may be incompatible with the processing technology of PPA, resulting in processing difficulties or product molding problems. In addition, the added flame retardant needs to have good compatibility with PPA. If it is incompatible, it will have a greater impact on the PPA material.

[0051] The present invention does not require the addition of a flame retardant because the present invention uses a phenolic compound as an antioxidant. The hydroxyl group in the phenolic compound can react with the amine group in PPA to form a stable phenolamine, thereby improving the antioxidant performance of the composite material while effectively improving the flame retardancy of the composite material. In addition, the phenolic compound and the added β-silicon nitride have a synergistic effect, utilizing the high thermal conductivity of β-silicon nitride to improve the thermal conductivity coefficient of the material, thereby further improving the flame retardancy of the composite material.

[0052] As an optional embodiment of the present invention, the lubricant is one or more of paraffin wax, polyethylene wax, polypropylene wax, polysiloxane, and silicone powder.

[0053] As an optional embodiment of the present invention, the nucleating agent is a sodium salt of a long carbon chain linear saturated carboxylic acid or a calcium salt of a long carbon chain linear saturated carboxylic acid.

[0054] As an optional embodiment of the present invention, the sodium salt of a long carbon chain linear saturated carboxylic acid includes one or more of sodium laurate, sodium stearate, sodium oleate, and sodium myristate;

[0055] And / or, the long carbon chain linear saturated carboxylic acid calcium salt includes one or more of TMN-102, calcium stearate, and calcium montanate.

[0056] According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned high-temperature resistant polyphthalamide composite material for LED lamp beads, comprising the following steps:

[0057] S1: Drying the raw materials;

[0058] S2: Place the dried raw materials in a blender and mix them evenly;

[0059] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder and extruded into granules.

[0060] As an optional embodiment of the present invention, in step S1, the drying condition is drying at 100-120° C. (such as 105° C., 110° C., 115° C., etc.) for 4-6 hours (such as 4.5 hours, 5 hours, 5.5 hours, etc.);

[0061] And / or, in step S2, the stirring time is 10-20 min (such as 12 min, 14 min, 16 min, 18 min, etc.).

[0062] As an optional embodiment of the present invention, the setting conditions of the twin-screw extruder are: zone 1 temperature 250-270°C (such as 255°C, 260°C, 265°C, etc.), zone 2 temperature 260-280°C (such as 265°C, 270°C, 275°C, etc.), zone 3 temperature 270-290°C (such as 275°C, 280°C, 285°C, etc.), zone 4 temperature 280-300°C (such as 285°C, 290°C, 295°C, etc.), zone 5 temperature 290-310°C (such as 295°C, 300°C, 305°C, etc.) etc.), the head temperature is 300-320℃ (such as 305℃, 310℃, 315℃, etc.); the screw speed is controlled at 220-350r / min (such as 240r / min, 260r / min, 280r / min, 300r / min, 320r / min, 340r / min, etc.), the mixture conveying time in the screw is 3-5min (such as 3.5min, 4min, 4.5min, etc.), and the pressure is 12-20Pa (such as 14Pa, 16Pa, 18Pa, etc.).

[0063] The present invention will be further described in detail below with reference to specific examples and comparative examples.

[0064] The polyphthalamide used was semi-aromatic nylon (PPAHTN 51G50, DuPont (China) Co., Ltd., USA);

[0065] The remaining raw materials are commercially available.

[0066] Example 1

[0067] S1: Place 65 kg of polyphthalamide, 35 kg of β-silicon nitride, 2 kg of maleic anhydride-grafted polyolefin, 0.2 kg of di-tert-butyl-p-cresol, 0.4 kg of polysiloxane and 0.3 kg of sodium stearate in an electric forced air drying oven at 120°C and dry for 6 h;

[0068] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0069] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 260°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 290°C, and the head temperature is 300°C; the screw speed is controlled at 220r / min, the conveying time of the mixture in the screw is 5min, and the pressure is 12Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0070] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this embodiment are shown in Table 1.

[0071] like Figure 1 , which is a photo of an LED lamp bead prepared using the high-temperature resistant polyphthalamide composite material obtained in this embodiment.

[0072] Example 2

[0073] S1: Place 45 kg of polyphthalamide, 55 kg of β-silicon nitride, 0.1 kg of maleic anhydride-grafted polyamide, 0.6 kg of butylated hydroxyanisole, 0.2 kg of paraffin wax, and 0.5 kg of TMN-102 in an electric forced air drying oven at 100°C and dry for 4 h;

[0074] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 10 minutes;

[0075] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 270°C, the temperature of zone 2 is 280°C, the temperature of zone 3 is 290°C, the temperature of zone 4 is 300°C, the temperature of zone 5 is 310°C, and the head temperature is 320°C; the screw speed is controlled at 350r / min, the conveying time of the mixture in the screw is 3min, and the pressure is 20Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0076] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this embodiment are shown in Table 1.

[0077] Example 3

[0078] S1: Place 55 kg of polyphthalamide, 45 kg of β-silicon nitride, 1 kg of maleic anhydride grafted polyether, 0.4 kg of tert-butylhydroxyanisole, 0.3 kg of polyethylene wax and polypropylene wax, and 0.4 kg of sodium laurate and sodium stearate in an electric forced air drying oven at 110°C and dry for 5 h;

[0079] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 15 minutes;

[0080] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 260°C, the temperature of zone 2 is 270°C, the temperature of zone 3 is 280°C, the temperature of zone 4 is 290°C, the temperature of zone 5 is 300°C, and the head temperature is 310°C; the screw speed is controlled at 300r / min, the conveying time of the mixture in the screw is 4min, and the pressure is 15Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0081] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this embodiment are shown in Table 1.

[0082] Example 4

[0083] S1: Place 60 kg of polyphthalamide, 50 kg of β-silicon nitride, 2 kg of maleic anhydride grafted polyolefin and maleic anhydride grafted polyester, 0.2 kg of propyl gallate, 0.4 kg of polysiloxane and silicone powder, and 0.5 kg of sodium myristate in an electric forced air drying oven at 120°C and dry for 6 h;

[0084] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0085] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 260°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 290°C, and the head temperature is 300°C; the screw speed is controlled at 220r / min, the conveying time of the mixture in the screw is 5min, and the pressure is 12Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0086] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this embodiment are shown in Table 1.

[0087] Example 5

[0088] S1: Place 65 kg of polyphthalamide, 55 kg of β-silicon nitride, 1 kg of maleic anhydride grafted polyether and maleic anhydride grafted polyamide, 0.6 kg of butylated hydroxyanisole and di-tert-butylated p-cresol, 0.4 kg of polyethylene wax, and 0.5 kg of calcium stearate in an electric forced air drying oven at 120°C and dry for 6 h;

[0089] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0090] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are: zone 1 temperature 250°C, zone 2 temperature 260°C, zone 3 temperature 270°C, zone 4 temperature 280°C, zone 5 temperature 290°C, and head temperature 300°C; the screw speed is controlled at 220r / min, the mixed material is conveyed in the screw for 5min, and the pressure is 20Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0091] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this embodiment are shown in Table 1.

[0092] Comparative Example 1

[0093] S1: Place 65 kg of polyphthalamide, 2 kg of maleic anhydride grafted polyolefin, 0.2 kg of di-tert-butyl-p-cresol, 0.4 kg of polysiloxane and 0.3 kg of sodium stearate in an electric forced air drying oven at 120°C and dry for 6 h;

[0094] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0095] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 260°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 290°C, and the head temperature is 300°C; the screw speed is controlled at 220r / min, the conveying time of the mixture in the screw is 5min, and the pressure is 12Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0096] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this comparative example are shown in Table 1.

[0097] Comparative Example 2

[0098] S1: Place 65 kg of polyphthalamide, 35 kg of α-silicon nitride, 2 kg of maleic anhydride-grafted polyolefin, 0.2 kg of di-tert-butyl-p-cresol, 0.4 kg of polysiloxane and 0.3 kg of sodium stearate in an electric forced air drying oven at 120°C and dry for 6 h;

[0099] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0100] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 260°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 290°C, and the head temperature is 300°C; the screw speed is controlled at 220r / min, the conveying time of the mixture in the screw is 5min, and the pressure is 12Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0101] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this comparative example are shown in Table 1.

[0102] Comparative Example 3

[0103] S1: Place 65 kg of polyphthalamide, 35 kg of α-silicon nitride, 2 kg of maleic anhydride-grafted polyolefin, 0.2 kg of tris(2,4-di-tert-butylphenyl) phosphite, 0.4 kg of polysiloxane and 0.3 kg of sodium stearate in an electric forced air drying oven at 120°C and dry for 6 h;

[0104] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0105] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 260°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 290°C, and the head temperature is 300°C; the screw speed is controlled at 220r / min, the conveying time of the mixture in the screw is 5min, and the pressure is 12Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0106] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this comparative example are shown in Table 1.

[0107] Comparative Example 4

[0108] S1: Place 65 kg of polyphthalamide, 35 kg of β-silicon nitride, 2 kg of maleic anhydride-grafted polyolefin, 0.2 kg of tris(2,4-di-tert-butylphenyl)phosphite, 0.4 kg of polysiloxane, 0.3 kg of sodium stearate, and 0.5 kg of flame retardant OP1400 in an electric forced air drying oven at 120°C and dry for 6 h;

[0109] S2: Place the dried raw materials in a high-speed blender and stir until evenly mixed for 20 minutes;

[0110] S3: The uniformly mixed materials are melt-blended in a twin-screw extruder. The setting conditions of the twin-screw extruder are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 260°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 290°C, and the head temperature is 300°C; the screw speed is controlled at 220r / min, the conveying time of the mixture in the screw is 5min, and the pressure is 12Pa; after melt-blending extrusion, water cooling, air drying, pelletizing, and drying, a high-temperature resistant polyphthalamide composite material for LED lamp beads is obtained.

[0111] The performance data of the high-temperature resistant polyphthalamide composite material for LED lamp beads prepared in this comparative example are shown in Table 1.

[0112] Performance Comparison

[0113] The performance testing method adopted in the present invention is as follows:

[0114] Tensile strength: tested according to GB / T 1040; specimen type is Type I, specimen dimensions (mm): 170 (length) × (20 ± 0.2) (end width) × (4 ± 0.2) (thickness), tensile speed is 50 mm / min;

[0115] Bending strength: Tested according to GB / T9341 standard; specimen type: specimen size (mm): (80±2)×(10±0.2)×(4±0.2), bending speed: 20mm / min;

[0116] Thermal conductivity: tested according to ASTM D5470 standard, specimen type: specimen size (mm): (50+0.2)×(5±0.02)×(5±0.02);

[0117] Thermal deformation temperature: tested according to GB / T 1634.2, load 1.80MPa, span 100mm;

[0118] Flame retardant performance: tested according to UL-94 standard, the sample thickness is about 1.5 mm; flame retardant level: V0>V1>HB.

[0119] The LED lamp beads prepared in Examples 1-5 and Comparative Examples 1-3 were injection molded using a high-temperature resistant polyphthalamide composite material on an injection molding machine to prepare samples, and performance tests were performed, as shown in Table 1:

[0120] Table 1

[0121]

[0122] As shown in Table 1, compared with Example 1 of the present invention, since no silicon nitride is added in Comparative Example 1, the tensile strength and flexural strength of the composite material prepared in Comparative Example 1 are both lower than those in Example 1, especially the heat deformation temperature, which is significantly lower than that in Example 1.

[0123] As shown in Table 1, compared with Example 1 of the present invention, since α-silicon nitride is added in Comparative Example 2, the crystal structure of α-silicon nitride is different from that of β-silicon nitride, resulting in different material properties, so the various performance indicators of the composite material prepared in Comparative Example 2 are all lower than those in Example 1.

[0124] As shown in Table 1, compared with Example 1 of the present invention, in Comparative Example 3, since the antioxidant added in Comparative Example 3 is tris(2,4-di-tert-butylphenyl)phosphite, which does not contain a phenolic structure, and α-silicon nitride is added, the thermal conductivity of α-silicon nitride is affected by its structure and is smaller than that of β-silicon nitride, the composite material prepared in Comparative Example 3 has poor flame retardant properties.

[0125] As shown in Table 1, compared with Example 1 of the present invention, in Comparative Example 4, the antioxidant added in Comparative Example 4 is tris(2,4-di-tert-butylphenyl) phosphite, which does not contain a phenolic structure, and a flame retardant is additionally added. The flame retardant OP1400 has poor compatibility with the PPA material, thereby affecting the mechanical properties of Comparative Example 4. However, the flame retardant performance can still be maintained at the V0 level.

[0126] In summary, the present invention blends β-silicon nitride with polyphthalamide, and a higher content of β-silicon nitride is randomly dispersed in the material matrix, which is conducive to overlapping with the structure of the matrix material. At this time, a certain synergistic effect is produced between the PPA and β-silicon nitride materials with different structures and thermal conductivity. The added β-silicon nitride will form a cubic structure inside the PPA, thereby comprehensively enhancing the stiffness of the material, allowing the material to absorb a lot of external forces at the same time, making its tensile strength 160-200MPa and its bending strength 282-320MPa; and the cubic structure formed by β-silicon nitride inside the PPA can effectively resist the slight vertical movement of the molecules inside the material under high temperature conditions, greatly delaying the movement of the molecules inside the material, effectively improving the high temperature resistance of the material, and making its thermal deformation temperature 260-280℃; and the high thermal conductivity of β-silicon nitride can significantly improve the thermal conductivity of the material, making its thermal conductivity 2.9-3.7W / (m·k).

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high temperature resistant polyphthalamide composite material for LED lamp beads, characterized in that: According to mass percentage, it is composed of 45-65% of polyphthalamide, 35-55% of silicon nitride, 0.1-2% of compatibilizer, 0.2-0.6% of antioxidant, 0.2-0.4% of lubricant and 0.3-0.5% of nucleating agent, and the sum of the mass percentages of the above components is 100%; The silicon nitride is β-silicon nitride; The compatibilizer is a polymer containing maleic anhydride grafts; The antioxidant is one or more of butylated hydroxyanisole, di-tert-butylated p-cresol, tert-butylated hydroxyanisole, and propyl gallate.

2. The high temperature resistant polyphthalamide composite material for LED lamp beads according to claim 1, characterized in that: The β-silicon nitride is in powder form with a particle size of ≤50 μm; And / or, the β-silicon nitride powder is synthesized by self-propagating high temperature synthesis.

3. The high temperature resistant polyphthalamide composite material for LED lamp beads according to claim 1, characterized in that: The polymer containing maleic anhydride grafts includes one or more of maleic anhydride grafted polyolefins, maleic anhydride grafted polyesters, maleic anhydride grafted polyethers, and maleic anhydride grafted polyamides.

4. The high temperature resistant polyphthalamide composite material for LED lamp beads according to claim 1, characterized in that: The lubricant is one or more of paraffin wax, polyethylene wax, polypropylene wax, polysiloxane, and silicone powder.

5. The high temperature resistant polyphthalamide composite material for LED lamp beads according to claim 1, characterized in that: The nucleating agent is a sodium salt of a long carbon chain linear saturated carboxylic acid or a calcium salt of a long carbon chain linear saturated carboxylic acid.

6. The high temperature resistant polyphthalamide composite material for LED lamp beads according to claim 5, characterized in that: The long carbon chain linear saturated carboxylic acid sodium salt includes one or more of sodium laurate, sodium stearate, sodium oleate, and sodium myristate; And / or, the long carbon chain linear saturated carboxylic acid calcium salt includes one or more of TMN-102, calcium stearate, and calcium montanate.

7. A method for preparing the high-temperature resistant polyphthalamide composite material for LED lamp beads according to any one of claims 1 to 6, characterized in that: The steps include: S1: drying the raw materials; S2: Place the dried raw materials in a blender and mix them evenly; S3: The uniformly mixed materials are melt-blended in a twin-screw extruder and extruded into granules.

8. The method for preparing the high-temperature resistant polyphthalamide composite material for LED lamp beads according to claim 7, characterized in that: In step S1, the drying condition is drying at 100-120°C for 4-6 hours; And / or, in step S2, the stirring time is 10-20 minutes.

9. The method for preparing the high-temperature resistant polyphthalamide composite material for LED lamp beads according to claim 7, characterized in that: The setting conditions of the twin-screw extruder are: zone 1 temperature 250-270°C, zone 2 temperature 260-280°C, zone 3 temperature 270-290°C, zone 4 temperature 280-300°C, zone 5 temperature 290-310°C, and head temperature of 300-320°C; the screw speed is controlled at 220-350r / min, the mixed material conveying time in the screw is 3-5min, and the pressure is 12-20Pa.

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