CN118599310A - A high temperature resistant polyphthalamide composite material for LED lamp beads and preparation method thereof - Google Patents

Abstract

The present invention provides a high temperature resistant polyphthalamide composite material for LED lamp beads and a preparation method thereof, which relates to the technical field of polymer materials, and 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, and utilizes the synergistic effect between PPA and β-silicon nitride materials with different structures and thermal conductivity: the added β-silicon nitride forms 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, and effectively improving the high temperature resistance and thermal conductivity of the material.

Description

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

Technical Field

The 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

Polyphthalamide (PPA) is a semi-aromatic polyamide. It uses isophthalic acid or terephthalic acid as the main synthetic raw material and is a semi-crystalline thermoplastic functional material. PPA is currently the most commercially valuable semi-aromatic polyamide. The successful production of high-temperature resistant PPA supplements the original differences between engineering plastics and special polymers in terms of cost performance and function. Compared with some fully aromatic polyamides, the process of PPA is relatively simple, and it is easier to blow mold, injection mold and extrusion mold. In addition, the mechanical properties, thermal conductivity, heat resistance and chemical corrosion resistance of PPA are superior to those of aliphatic polyamides, and it has good performance in heat, electricity, physics and chemical resistance. This makes PPA composite materials have broad application prospects in the fields of electronics, electrical engineering, mechanical engineering, etc.

In the existing technology, after PPA is modified with carbon fiber, glass fiber and other fillers, it can achieve very good mechanical properties, and can maintain these special properties over a long time and temperature range. Therefore, PPA has become a good engineering plastic that can completely replace metal materials, and has very common application scenarios in various industries such as automobiles, electrical appliances, and electronics.

However, the research on the processing and modification of traditional PPA in China is still imperfect and immature, and the thermal conductivity and heat resistance of PPA need to be improved. Therefore, it is urgent to conduct modification research on the thermal conductivity and heat resistance of high temperature resistant PPA.

Summary of the invention

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, wherein β-silicon nitride is blended with polyphthalamide, and the synergistic effect between PPA and β-silicon nitride materials having different structures and thermal conductivities is utilized: the added β-silicon nitride forms a cubic structure inside the PPA, thereby comprehensively enhancing the rigidity of the material, so that the material can absorb a lot of external forces at the same time; and the cubic structure formed by the β-silicon nitride inside the PPA can effectively resist the slight movement of the molecules inside the material in the vertical direction 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 thermal conductivity of β-silicon nitride is relatively high, which can significantly improve the thermal conductivity of the material.

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

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

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%.

Further, on the basis of the above technical solution of the present invention, the silicon nitride is β-silicon nitride;

And/or, 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.

Further, on the basis of the above technical solution of the present invention, the compatibilizer is a polymer containing maleic anhydride grafts;

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.

Further, on the basis of the above technical solution of the present invention, the antioxidant is a compound containing a phenol group;

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

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.

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.

Further, on the basis of 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 myristic acid;

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

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

S1: drying the raw materials;

S2: putting the dried raw materials into a blender and mixing them evenly;

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

Further, on the basis of the above technical solution of the present invention, 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 min.

Further, on the basis of the above technical solution of the present invention, the setting conditions of the twin-screw extruder are: 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.

The present invention provides a high temperature resistant polyphthalamide composite material for LED lamp beads and a preparation method thereof, and the beneficial effects are as follows:

1. The present invention blends β-silicon nitride with polyphthalamide, and a relatively high 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 and allowing the material to absorb a lot of external forces at the same time.

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.

3. 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, which can effectively improve the flame retardancy of the composite material while improving the antioxidant performance of the composite material; and it has a synergistic effect with β-silicon nitride, using the high thermal conductivity of β-silicon nitride to improve the thermal conductivity of the material, thereby further improving the flame retardancy of the composite material. It avoids the incompatibility between the flame retardant and polyphthalamide, which affects the performance of the composite material.

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 bonding with polar polymers (such as nylon, polyester, epoxy resin, etc.).

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 bending 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

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

FIG. 1 is a photo of an LED lamp bead prepared from the composite material provided in Example 1 of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment 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 only 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 ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The process parameters of the following embodiments that do not specify specific conditions are usually based on conventional conditions.

The endpoints and any values of the ranges disclosed in the present invention 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 endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

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:

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%.

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

And/or, 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, see Wang Huabin et al. "Growth Mechanism of Silicon Nitride by Self-propagating High Temperature Synthesis".

Specifically, the present invention blends β-silicon nitride with polyphthalamide, because β-silicon nitride is a material with a cubic crystal structure, and a high 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 PPA and β-silicon nitride materials with different structures and thermal conductivity. The added β-silicon nitride will form a cubic structure inside PPA, thereby comprehensively enhancing the rigidity of the material, so that the material can absorb a lot of external forces at the same time; and the cubic structure formed by β-silicon nitride inside PPA can effectively resist the slight movement of the molecules inside the material in the vertical direction under high temperature conditions, greatly delaying the movement of the molecules inside the material, and effectively improving the high temperature resistance of the material.

Both α-silicon nitride and β-silicon nitride are hexagonal crystals, but α-silicon nitride is equiaxed and β-silicon nitride is rod-shaped. The difference in crystal structure will lead to different material properties. In terms of mechanical properties, α-silicon nitride has higher hardness than β-silicon nitride crystals, but rod-shaped β-silicon nitride is more conducive to crack deflection and grain extraction, increases crack propagation resistance, and has higher toughness and strength. Moreover, the thermal conductivity of silicon nitride is greatly affected by the crystal form, so the thermal conductivity of β-silicon nitride is much higher than that of α-silicon nitride.

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.

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

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.

Specifically, the present invention adopts a polymer containing maleic anhydride grafts as a compatibilizer. The polymer containing maleic anhydride grafts is usually composed of a main chain and multiple side chains. This structure enables the grafted polymer to act as a bridge between different polymers, improve the interfacial compatibility between two or more polymers, and reduce phase separation at the interface; and the polymer containing maleic anhydride grafts contains polar carboxyl (-COOH) functional groups, which enables 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.

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

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

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 retardants need to have good compatibility with PPA. If they are incompatible, they will have a greater impact on the PPA material.

The present invention does not need to add flame retardants because the present invention uses compounds containing phenol groups as antioxidants. The hydroxyl groups in the phenolic compounds can react with the amine groups in PPA to form stable phenolamines, thereby improving the antioxidant properties of the composite material while effectively improving the flame retardancy of the composite material. In addition, the phenolic compounds have a synergistic effect with the added β-silicon nitride, utilizing the high thermal conductivity of β-silicon nitride to improve the thermal conductivity of the material, thereby further improving the flame retardancy of the composite material.

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.

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.

As an optional embodiment 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 myristic acid;

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

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:

S1: drying the raw materials;

S2: putting the dried raw materials into a blender and mixing them evenly;

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

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 h (such as 4.5 h, 5 h, 5.5 h, etc.);

And/or, in step S2, the stirring time is 10-20 min (e.g., 12 min, 14 min, 16 min, 18 min, etc.).

As an optional embodiment of the present invention, the setting conditions of the twin-screw extruder are: the temperature of zone 1 is 250-270°C (for example, 255°C, 260°C, 265°C, etc.), the temperature of zone 2 is 260-280°C (for example, 265°C, 270°C, 275°C, etc.), the temperature of zone 3 is 270-290°C (for example, 275°C, 280°C, 285°C, etc.), the temperature of zone 4 is 280-300°C (for example, 285°C, 290°C, 295°C, etc.), the temperature of zone 5 is 290-310°C (for example, 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.).

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

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

The remaining raw materials are commercially available.

Example 1

S1: 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 were placed in an electric heated forced air drying oven at 120° C. and dried for 6 h;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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 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.

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

As shown in FIG. 1 , a photo of an LED lamp bead prepared using the high temperature resistant polyphthalamide composite material prepared by the LED lamp bead of this embodiment is shown.

Example 2

S1: 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 were placed in an electric heated forced air drying oven at 100°C and dried for 4 hours;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 10 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and the setting conditions of the twin-screw extruder are: zone 1 temperature 270°C, zone 2 temperature 280°C, zone 3 temperature 290°C, zone 4 temperature 300°C, zone 5 temperature 310°C, and head temperature 320°C; the screw speed is controlled at 350r/min, the mixed material is conveyed in the screw for 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.

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

Example 3

S1: 55 kg of polyphthalamide, 45 kg of β-silicon nitride, 1 kg of maleic anhydride grafted polyether, 0.4 kg of tert-butyl hydroxyanisole, 0.3 kg of polyethylene wax and polypropylene wax, and 0.4 kg of sodium laurate and sodium stearate were placed in an electric blast drying oven at 110° C. and dried for 5 h;

S2: Place the dried raw materials in a high-speed mixer and stir to mix evenly for 15 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and the setting conditions of the twin-screw extruder are: zone 1 temperature 260°C, zone 2 temperature 270°C, zone 3 temperature 280°C, zone 4 temperature 290°C, zone 5 temperature 300°C, and head temperature 310°C; the screw speed is controlled at 300r/min, the mixed material is conveyed in the screw for 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.

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

Example 4

S1: 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 were placed in an electric heated forced air drying oven at 120°C and dried for 6 hours;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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 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.

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

Example 5

S1: 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-butyl-p-cresol, 0.4 kg of polyethylene wax, and 0.5 kg of calcium stearate were placed in an electric heated forced air drying oven at 120° C. and dried for 6 hours;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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.

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

Comparative Example 1

S1: 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 were placed in an electric heated forced air drying oven at 120° C. and dried for 6 h;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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 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.

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.

Comparative Example 2

S1: 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 were placed in an electric heated forced air drying oven at 120° C. and dried for 6 h;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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 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.

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.

Comparative Example 3

S1: 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 were placed in an electric heated forced air drying oven at 120° C. and dried for 6 h;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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 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.

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.

Comparative Example 4

S1: 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 were placed in an electric heated forced air drying oven at 120° C. and dried for 6 h;

S2: Place the dried raw materials in a high-speed stirrer and stir to mix evenly for 20 minutes;

S3: The uniformly mixed materials are melt-blended in a twin-screw extruder, and 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 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.

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.

Performance Comparison

The performance testing method adopted by the present invention is as follows:

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

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

Thermal conductivity: Tested according to ASTM D5470 standard, sample type: Sample size (mm): (50+0.2)×(5±0.02)×(5±0.02);

Heat deformation temperature: tested according to GB/T 1634.2 standard, load is 1.80MPa, span is 100mm;

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

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 machine to prepare samples, and performance tests were performed, as shown in Table 1:

Table 1

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.

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

As shown in Table 1, compared with Example 1 of the present invention, 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.

As shown in Table 1, compared with Example 1 of the present invention, since 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, so the mechanical properties in Comparative Example 4 are affected, but the flame retardant performance can still be maintained at the V0 level.

In summary, the present invention blends β-silicon nitride with polyphthalamide, and a high 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, so that the material can absorb a lot of external forces at the same time, so that its tensile strength is 160-200MPa and its bending strength is 282-320MPa; and the cubic structure formed by β-silicon nitride inside the PPA can effectively resist the slight movement of the molecules inside the material in the vertical direction 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 thermal conductivity of β-silicon nitride is high, which can significantly improve the thermal conductivity of the material, making its thermal conductivity 2.9-3.7W/(m·k).

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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. The high-temperature-resistant polyphthalamide composite material for the LED lamp beads is characterized by comprising the following components in percentage by mass:

45-65% of polyphthalamide, 35-55% of silicon nitride, 0.1-2% of compatilizer, 0.2-0.6% of antioxidant, 0.2-0.4% of lubricant and 0.3-0.5% of nucleating agent.

2. The high temperature resistant polyphthalamide composite material for LED lamp beads of claim 1, wherein the silicon nitride is beta-silicon nitride;

and/or the beta-silicon nitride is in powder shape, and the grain diameter is less than or equal to 50 mu m.

And/or, the beta-silicon nitride powder is synthesized by self-propagating high temperature.

3. The high temperature resistant polyphthalamide composite material for LED lamp beads according to claim 1, wherein the compatibilizer is a polymer containing maleic anhydride grafts;

And/or the polymer containing the maleic anhydride graft comprises one or more of maleic anhydride grafted polyolefin, maleic anhydride grafted polyester, maleic anhydride grafted polyether and maleic anhydride grafted polyamide.

4. The high temperature resistant polyphthalamide composite material for the LED lamp beads according to claim 1, wherein the antioxidant is a compound containing a phenolic group;

and/or the compound containing phenolic group comprises one or more of butyl hydroxy anisole, di-tert-butyl p-cresol, tert-butyl hydroxy anisole and propyl gallate.

5. The high temperature resistant polyphthalamide composite material for the LED lamp beads according to claim 1, wherein the lubricant is one or more of paraffin wax, polyethylene wax, polypropylene wax, polysiloxane and silicone powder.

6. The high temperature resistant polyphthalamide composite material for the LED lamp beads according to claim 1, wherein the nucleating agent is long carbon chain linear saturated carboxylic acid sodium salt or long carbon chain linear saturated carboxylic acid calcium salt.

7. The high temperature resistant polyphthalamide composite material for the LED lamp beads according to claim 6, wherein the long carbon chain linear saturated carboxylic acid sodium salt comprises one or more of sodium laurate, sodium stearate, sodium oleate, sodium myristate;

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

8. A method for preparing the high temperature resistant polyphthalamide composite material for the LED lamp beads according to any one of claims 1 to 7, which is characterized by comprising the following steps:

s1: drying the raw materials;

s2: placing the dried raw materials into a stirrer to be uniformly mixed;

s3: and (3) carrying out melt blending, extrusion granulation and the like on the uniformly mixed materials in a double-screw extruder.

9. The method for preparing the high temperature resistant polyphthalamide composite material for the LED lamp beads according to claim 8, wherein in the step S1, the drying condition is that the mixture is dried for 4-6 hours at 100-120 ℃;

and/or in the step S2, stirring time is 10-20min.

10. The method for preparing the high-temperature-resistant polyphthalamide composite material for the LED lamp beads, which is disclosed in claim 8, is characterized in that the setting condition of the double-screw extruder is that the temperature of the first zone is 250-270 ℃, the temperature of the second zone is 260-280 ℃, the temperature of the third zone is 270-290 ℃, the temperature of the fourth zone is 280-300 ℃, the temperature of the fifth zone is 290-310 ℃, and the temperature of the machine head is 300-320 ℃; the rotating speed of the screw is controlled to be 220-350r/min, the conveying time of the mixture in the screw is 3-5min, and the pressure is 12-20Pa.