High-performance high-thermal-conductivity plastic and preparation method thereof

Abstract

The invention relates to the technical field of thermal conductive plastics, in particular to a high-performance and high-thermal-conductivity plastic and a preparation method thereof.The high-performance and high-thermal-conductivity plastic is prepared from, by weight, 40-60 parts of nylon resin, 5-10 parts of flame retardant, 20-35 parts of thermal conductive filler, 10-15 parts of glass fiber, 1-2 parts of coupling agent and 1-2 parts of antioxidant. The high-performance and high-thermal-conductivity plastic prepared by the preparation method disclosed by the invention has excellent thermal conductivity and relatively good mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat-conducting plastics, in particular to a high-performance high-heat-conducting plastic and a preparation method thereof. BACKGROUND

[0002] Heat-conducting plastics are applied in the fields of consumer electronics, new energy vehicles, medical devices, household appliances, buildings, etc. Heat-conducting plastics are usually high-molecular materials composed of heat-conducting fillers such as ceramic particles, carbon fibers, graphene, etc. and engineering plastic matrices such as PPS, PA, PC, PPA, etc. and have the characteristics of lightweight, insulation, easy processing and heat conduction of plastics.

[0003] Traditional heat-conducting substances are mostly metals such as Ag, Cu, Al and metal oxides such as Al2O3, MgO, BeO and other non-metallic materials such as graphite, carbon black, Si3N4, AlN, etc. Generally, high-molecular materials are poor heat conductors, and only by filling high-heat-conducting fillers can the thermal conductivity of the material be increased. The heat-conducting performance of the fillers and their distribution in the high-molecular matrix determine the heat-conducting performance of the entire material. How to form a heat-conducting network in the system to the greatest extent to achieve effective heat conduction is a key problem that must be considered.

[0004] Patent CN105086431A discloses a heat-conducting, insulating and flame-retardant nylon alloy for LED and a preparation method thereof. The nylon alloy is composed of the following components in weight percentage: 5-80% of a first nylon resin, 5-75% of magnesium oxide, 1-30% of a flame retardant, 0.1-1.5% of an antioxidant, 0.1-3% of a lubricant and 1-15% of a compatibilizer. The application uses magnesium oxide whiskers to prepare a high-molecular material with good heat conduction, insulation, aging resistance and flame retardation, which can replace metals and be used in the production of LED lamp heat sinks. However, the poor dispersibility of magnesium oxide whiskers in the nylon alloy may affect the heat-conducting performance of different parts of the nylon alloy.

[0005] Patent CN118546521A discloses a kind of graphene modified high thermal conductive plastic and its preparation method, by nylon matrix resin, graphene modified polyaniline resin, surface modified aramid fiber, nano high thermal conductive insulating filler is prepared;The mass of surface modified aramid fiber accounts for 6-8% of the total mass of high thermal conductive plastic;The mass of nano high thermal conductive insulating filler accounts for 24-28% of the total mass of high thermal conductive plastic;The mass of graphene modified polyaniline resin accounts for 28-36% of the total mass of high thermal conductive plastic;Nylon matrix resin is PA66, PA612 with mass ratio (6-8):(2-4) Composition.Nano high thermal conductive insulating filler is composed of spherical alumina, spherical aluminum nitride, boron nitride nanosheet, and the spherical alumina is surface-doped graphene modified spherical alumina.The high thermal conductive plastic prepared in this application has good thermal conductivity and heat dissipation, but the dispersibility of graphene in the nylon matrix resin is poor, which may affect the mechanical properties of the high thermal conductive plastic.

[0006] Therefore, there is an urgent need in the market for a high thermal conductive plastic with excellent mechanical properties. SUMMARY

[0007] In view of the problems in the prior art, the purpose of the present application is to obtain a high-performance high thermal conductive plastic with excellent mechanical properties.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0009] In one aspect, the present application provides a high-performance high thermal conductive plastic, which comprises the following raw materials in parts by weight: nylon resin 40-60 parts, flame retardant 5-10 parts, thermal conductive filler 20-35 parts, glass fiber 10-15 parts, coupling agent 1-2 parts, and antioxidant 1-2 parts.

[0010] The high-performance high thermal conductive plastic prepared by blending nylon resin, flame retardant, thermal conductive filler, glass fiber, coupling agent and antioxidant has excellent mechanical properties and thermal conductivity.

[0011] In some embodiments, the nylon resin is a combination of nylon 6 and nylon 66.

[0012] Preferably, the mass ratio of nylon 6 to nylon 66 is (1.5-2):1.

[0013] In some embodiments, the preparation method of the thermal conductive filler comprises the following steps:

[0014] A1, mixing graphene, concentrated sulfuric acid and sodium nitrate in an ice water bath, stirring evenly, adding potassium permanganate, keeping the temperature at 0℃, continuing to stir for 8-12h, adding deionized water to dilute, then adding hydrogen peroxide and stirring for 30-60min, filtering, obtaining a solid, putting the solid into 1-3mol / L hydrochloric acid and stirring for 20-30min, centrifuging, washing and drying to obtain graphene oxide;

[0015] A2, adding aluminum isopropyl alcohol and hexamethylenetetramine into an aqueous ethanol solution, stirring at 50-60℃ for 3-5h to obtain an aluminum precursor; adding graphene oxide obtained in step A1 and polyvinylpyrrolidone into deionized water, ultrasonicating for 2-4h, adding the aluminum precursor, stirring at 60-80℃ for 4-6h, drying, and calcining at 800-1000℃ for 3-5h in an ammonia atmosphere to obtain aluminum nitride coated graphene;

[0016] A3, adding aluminum nitride coated graphene and KH-550 silane coupling agent into an aqueous ethanol solution, stirring at 30-40℃ for 2-4h, filtering and drying to obtain a solid product;

[0017] A4, adding the solid product obtained in step A3, tetrabutyl titanate and hydrogenated cinnamic acid into DMF, stirring at 60-80℃ for 4-6h, filtering and drying to obtain a heat-conducting filler.

[0018] The present application can obtain aluminum nitride coated graphene by reacting graphene oxide and aluminum precursor and then calcining, and can obtain a heat-conducting filler by reacting the aluminum nitride coated graphene with KH550 silane coupling agent and hydrogenated cinnamic acid. Adding the heat-conducting filler into a nylon heat-conducting plastic system can make the plastic have excellent heat-conducting performance and mechanical properties. This may be because, on the one hand, the interaction between graphene can be weakened after the graphene is coated with aluminum nitride, so that the heat-conducting filler has better dispersibility in the nylon resin, the aluminum nitride coating layer can inhibit the sliding of the graphene sheet layer, so that the tensile strength of the high-heat-conducting plastic is improved compared with the pure graphene filling system, the phonon transmission of aluminum nitride and the electron / phonon conduction of graphene are complementary, which reduces the interface thermal resistance, and the aluminum nitride can connect the graphene sheet layer as a "heat-conducting bridge" to form a three-dimensional heat-conducting path, so that the nylon plastic has excellent heat-conducting performance; on the other hand, the reaction of KH550 silane coupling agent and hydrogenated cinnamic acid can obtain amide groups, which can graft the same amide segment on the aluminum nitride coated graphene as the nylon resin, so that the dispersibility of the aluminum nitride coated graphene in the nylon resin is further improved, and the benzene ring on the hydrogenated cinnamic acid can produce π-π conjugation with graphene, which can enhance the continuity of the phonon transmission path and improve the heat-conducting performance of the nylon plastic.

[0019] In some embodiments, the mass ratio of graphene oxide to aluminum isopropyl alcohol in step A2 is 1:(3-5).

[0020] The application can make a small part of graphene exposed on the surface of the conductive filler and the benzene ring of the hydrogenated cinnamic acid to produce a pi-pi conjugation effect, enhance the continuity of the phonon transmission path, and improve the thermal conductivity of the nylon plastic.

[0021] In some embodiments, the mass ratio of the aluminum nitride coated graphene and the KH-550 silane coupling agent in step A3 is 1:(0.1-0.3).

[0022] In some embodiments, the mass ratio of the solid product and the hydrogenated cinnamic acid in step A4 is 1:(0.05-0.15).

[0023] The application can make the high-thermal-conductivity plastic have excellent thermal conductivity and excellent mechanical properties by limiting the ratio of the aluminum nitride coated graphene and the KH-550 silane coupling agent and the ratio of the solid product and the hydrogenated cinnamic acid. This may be because a small amount of hydrogenated cinnamic acid remains in the system, and the carboxyl group can form a hydrogen bond with the amide group on the nylon resin, weaken the hydrogen bond network between the nylon molecular chains, reduce the chain segment movement resistance, and make the thermal conductive filler more easily dispersed in the nylon resin.

[0024] In some embodiments, the flame retardant is one or more of a halogen-based flame retardant, a metal hydroxide flame retardant, a phosphorus-based flame retardant, and a nitrogen-based flame retardant.

[0025] In some embodiments, the glass fiber has a diameter of 10-20 μm and a length of 0.2-1 mm.

[0026] In some embodiments, the antioxidant is one or more of a hindered phenol, a phosphite, a thioester, a benzofuran, and a hydroxylamine antioxidant.

[0027] Preferably, the antioxidant is antioxidant 1010.

[0028] Another aspect of the application provides a method for preparing a high-performance high-thermal-conductivity plastic, comprising the following steps: first, ball-milling the thermal conductive filler with the glass fiber and the coupling agent for pretreatment, and then melt blending and extruding the nylon resin, the flame retardant, and the antioxidant to obtain the high-performance high-thermal-conductivity plastic.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] (1) The high-performance high-thermal-conductivity plastic prepared by blending the nylon resin, the flame retardant, the thermal conductive filler, the glass fiber, the coupling agent, and the antioxidant has excellent mechanical properties and thermal conductivity.

[0031] (2) The graphene coated with aluminum nitride prepared by the reaction of graphene oxide and aluminum precursor and then calcination can weaken the interaction force between the graphene, so that the heat-conducting filler has better dispersibility in the nylon resin. The graphene coated with aluminum nitride can also inhibit the sliding of the graphene sheet layer, so that the tensile strength of the high-thermal-conductivity plastic is improved compared with the pure graphene filling system. The phonon transmission of the aluminum nitride and the electron / phonon conduction of the graphene are complementary, which reduces the interface thermal resistance. The aluminum nitride can be connected to the graphene sheet layer as a "thermal-conductivity bridge" to form a three-dimensional thermal-conductivity path, so that the nylon plastic has excellent thermal-conductivity performance.

[0032] (3) The heat-conducting filler is obtained by the reaction of the graphene coated with aluminum nitride, KH550 silane coupling agent and hydrogenated cinnamic acid. The reaction of the KH550 silane coupling agent and the hydrogenated cinnamic acid obtains an amide group, so that the graphene coated with aluminum nitride is grafted with the same amide segment as the nylon resin, and the dispersibility of the graphene coated with aluminum nitride in the nylon resin is further improved. The benzene ring on the hydrogenated cinnamic acid can produce a π-π conjugation effect with the graphene, so that the continuity of the phonon transmission path is enhanced, and the thermal-conductivity performance of the nylon plastic is improved. DETAILED DESCRIPTION

[0033] The application will be described in detail below with reference to specific embodiments. It should be noted that the following examples are examples of the application and are only used to illustrate the application, but not to limit the application. Other combinations and various modifications within the concept of the application can be made without departing from the spirit or scope of the application.

[0034] In the following examples and comparative examples, the compounds and related reagents used except for the heat-conducting filler can be purchased from the market. Among them, the type of nylon 6 is BASF FP10KT; the type of nylon 66 is BASF A3K A3X2G7; the graphene is nano graphene sheet with a particle size of 5-10 μm, purchased from Beijing Deke Daojin Technology Co., Ltd.; the diameter of the glass fiber is 10-20 μm, and the length is 0.2-1 mm; the coupling agent is a titanate coupling agent with a type of NDZ-101.

[0035] Preparation Example 1

[0036] The preparation method of the heat-conducting filler-1 comprises the following steps:

[0037] A1, in an ice water bath, 10 g of nano graphene sheet, 230 ml of 98wt% concentrated sulfuric acid and 6 g of sodium nitrate were mixed and stirred uniformly, 30 g of potassium permanganate was added, the temperature was kept at 0℃, and the stirring was continued for 10 h, deionized water was added for dilution, 70 ml of hydrogen peroxide was added and stirred for 45 min, and then the solid was obtained by suction filtration, and the solid was placed in 300 ml of 2 mol / L hydrochloric acid and stirred for 25 min, centrifuged, washed and dried to obtain graphene oxide;

[0038] A2, 40 g aluminum isopropoxide and 8 g hexamethylenetetramine were added into 200 ml 75 wt% aqueous ethanol solution, stirred at 55℃ for 4 h to obtain an aluminum precursor; 10 g graphene oxide obtained in step A1 and 3 g polyvinylpyrrolidone were added into 100 ml deionized water, ultrasonic for 3 h, and then added into the aluminum precursor, stirred at 70℃ for 5 h, dried, and calcined at 900℃ for 4 h in an ammonia atmosphere to obtain aluminum nitride-coated graphene;

[0039] A3, 10 g aluminum nitride-coated graphene and 2 g KH-550 silane coupling agent were added into 100 ml 90 wt% aqueous ethanol solution, stirred at 35℃ for 3 h, filtered and dried to obtain a solid product;

[0040] A4, 10 g solid product obtained in step A3, 0.2 g tetrabutyl titanate and 1 g hydrogenated cinnamic acid were added into 100 ml DMF, stirred at 70℃ for 5 h, filtered and dried to obtain a thermally conductive filler-1.

[0041] Preparation Example 2

[0042] The preparation method of the thermally conductive filler-2 was the same as that of Preparation Example 1, except that the amount of aluminum isopropoxide added was 55 g.

[0043] Preparation Example 3

[0044] The preparation method of the thermally conductive filler-3 was the same as that of Preparation Example 1, except that the amount of KH-550 silane coupling agent added was 4 g.

[0045] Preparation Example 4

[0046] The preparation method of the thermally conductive filler-4 was the same as that of Preparation Example 1, except that the amount of hydrogenated cinnamic acid added was 2 g.

[0047] Example 1

[0048] A high-performance high-thermal-conductivity plastic, comprising the following raw materials in parts by weight: nylon resin 50 parts, melamine cyanurate 7 parts, thermally conductive filler-1 27 parts, glass fiber 12 parts, titanate coupling agent 1.5 parts, antioxidant 1010 1.5 parts.

[0049] The preparation method of the high-performance high-thermal-conductivity plastic of the present example comprises the following steps: first, the thermally conductive filler-1 is pretreated with glass fiber and titanate coupling agent by ball milling, the ball material ratio is 15:1, and the ball milling time is 4 h; then, the nylon resin, melamine cyanurate and antioxidant 1010 are melt blended and extruded, the double screw extrusion temperature is 265℃, and the rotation speed is 300 rpm, to obtain the high-performance high-thermal-conductivity plastic.

[0050] The nylon resin is a combination of nylon 6 and nylon 66, and the mass ratio of the two is 1.5:1.

[0051] Example 2

[0052] A high-performance high-thermal-conductivity plastic, comprising the following raw materials in parts by weight: nylon resin 40 parts, melamine cyanurate 5 parts, thermal conductive filler-1 20 parts, glass fiber 10 parts, titanate coupling agent 1 part, antioxidant 1010 1 part.

[0053] The preparation method of the high-performance high-thermal-conductivity plastic of the present embodiment comprises the following steps: first, the thermal conductive filler-1 is ball-milled with the glass fiber and the titanate coupling agent for pretreatment, the ball-to-material ratio is 15:1, and the ball-milling time is 4h; then, the nylon resin, the melamine cyanurate, and the antioxidant 1010 are melt-blended and extruded, the double-screw extrusion temperature is 250℃, and the rotation speed is 400rpm, to obtain the high-performance high-thermal-conductivity plastic.

[0054] The nylon resin is a combination of nylon 6 and nylon 66, and the mass ratio of the two is 1.5:1.

[0055] Example 3

[0056] A high-performance high-thermal-conductivity plastic, comprising the following raw materials in parts by weight: nylon resin 60 parts, melamine cyanurate 10 parts, thermal conductive filler-1 35 parts, glass fiber 15 parts, titanate coupling agent 2 parts, antioxidant 1010 2 parts.

[0057] The preparation method of the high-performance high-thermal-conductivity plastic of the present embodiment comprises the following steps: first, the thermal conductive filler-1 is ball-milled with the glass fiber and the titanate coupling agent for pretreatment, the ball-to-material ratio is 15:1, and the ball-milling time is 4h; then, the nylon resin, the melamine cyanurate, and the antioxidant 1010 are melt-blended and extruded, the double-screw extrusion temperature is 250℃, and the rotation speed is 400rpm, to obtain the high-performance high-thermal-conductivity plastic.

[0058] The nylon resin is a combination of nylon 6 and nylon 66, and the mass ratio of the two is 1.5:1.

[0059] Example 4

[0060] A high-performance high-thermal-conductivity plastic and a preparation method thereof, the specific implementation manner is the same as that of Example 1, and the only difference is that the thermal conductive filler-1 is replaced by the thermal conductive filler-2 in equal amount.

[0061] Example 5

[0062] A high-performance high-thermal-conductivity plastic and a preparation method thereof, the specific implementation manner is the same as that of Example 1, and the only difference is that the thermal conductive filler-1 is replaced by the thermal conductive filler-3 in equal amount.

[0063] Example 6

[0064] A high-performance high-thermal-conductivity plastic and a preparation method thereof, the specific implementation manner being the same as that of Example 1, except that the thermal-conductivity filler-1 is replaced by the thermal-conductivity filler-4 in equal amount.

[0065] Example 7

[0066] A high-performance high-thermal-conductivity plastic and a preparation method thereof, the specific implementation manner being the same as that of Example 1, except that the thermal-conductivity filler-1 is replaced by the nano-graphene sheet.

[0067] Performance test

[0068] The high-performance high-thermal-conductivity plastics obtained in the above examples and the comparative examples are subjected to performance test.

[0069] (1) Thermal-conductivity performance: the thermal-conductivity coefficient is determined according to the standard test method for thermal transmission properties of heat-conducting and electrically insulating materials (ASTM D5470-06).

[0070] (2) Bending strength: the bending strength is determined according to the standard test method for flexural properties of un-reinforced and reinforced plastics and electrical insulating materials (ASTM D790-03).

[0071] The test results are shown in Table 1.

[0072] Table 1

[0073] Group Thermal conductivity W / (m.K) Bending strength MPa Example 1 2.92 215.53 Example 2 2.97 212.36 Example 3 2.84 217.85 Example 4 2.55 214.52 Example 5 2.63 212.47 Example 6 2.65 212.65 Example 7 1.89 182.34

[0074] It can be seen from the data in Table 1 that the high-performance high-thermal-conductivity plastics of Examples 1-3 have excellent thermal-conductivity performance and mechanical properties, it can be seen from the comparison between Example 4 and Example 1 that changing the ratio of graphene oxide and aluminum isopropoxide will make the continuity of the enhanced phonon transmission path worse, and thus the thermal-conductivity performance of the thermal-conductivity plastic will decrease; it can be seen from the comparison between Examples 5, 6 and Example 1 that changing the ratio of the aluminum nitride-coated graphene and the KH-550 silane coupling agent or the solid product and the hydrogenated cinnamic acid will make the hydrogen bond network between the nylon molecular chains not easy to be weakened, and thus the thermal-conductivity performance and mechanical properties of the high-thermal-conductivity plastic will decrease; it can be seen from the comparison between Example 7 and Example 1 that when the nano-graphene sheet is directly used, the thermal-conductivity performance and mechanical properties of the plastic prepared are poor.

[0075] The above implementation manners are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable the person skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application, any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A high performance and high thermal conductivity plastic, characterized in that: The composition comprises the following raw materials in parts by weight: 40-60 parts of nylon resin, 5-10 parts of flame retardant, 20-35 parts of thermal conductive filler, 10-15 parts of glass fiber, 1-2 parts of coupling agent and 1-2 parts of antioxidant.

2. The high performance and high thermal conductivity plastic according to claim 1, characterized in that: The nylon resin is a composition of nylon 6 and nylon 66.

3. The high performance and high thermal conductivity plastic according to claim 1, characterized in that: The preparation method of the thermal conductive filler comprises the following steps: A1. In an ice-water bath, graphene, concentrated sulfuric acid, and sodium nitrate were mixed and stirred evenly. Potassium permanganate was added, and the temperature was maintained at 0°C. Stirring was continued for 8-12 hours. Deionized water was added to dilute the mixture, and hydrogen peroxide was added and stirred for 30-60 minutes. The mixture was filtered to obtain a solid. The solid was placed in 1-3 mol / L hydrochloric acid and stirred for 20-30 minutes. The solid was centrifuged, washed, and dried to obtain graphene oxide. A2. Add aluminum isopropoxide and hexamethylenetetramine to an ethanol aqueous solution, stir at 50-60° C. for 3-5 hours to obtain an aluminum precursor; add the graphene oxide and polyvinyl pyrrolidone obtained in step A1 to deionized water, sonicate for 2-4 hours, add to the aluminum precursor, stir at 60-80° C. for 4-6 hours, dry, and calcine at 800-1000° C. in an ammonia atmosphere for 3-5 hours to obtain aluminum nitride-coated graphene; A3, adding aluminum nitride-coated graphene and KH-550 silane coupling agent to ethanol aqueous solution, stirring at 30-40° C. for 2-4 hours, filtering and drying to obtain a solid product; A4. Add the solid product obtained in step A3, tetrabutyl titanate and hydrocinnamic acid to DMF, stir at 60-80° C. for 4-6 hours, filter and dry to obtain a thermally conductive filler.

4. The high performance and high thermal conductivity plastic according to claim 3, characterized in that: The mass ratio of graphene oxide to aluminum isopropoxide in step A2 is 1:(3-5).

5. The high performance and high thermal conductivity plastic according to claim 3, characterized in that: The mass ratio of the aluminum nitride-coated graphene to the KH-550 silane coupling agent in step A3 is 1:(0.1-0.3).

6. The high performance and high thermal conductivity plastic according to claim 3, characterized in that: The mass ratio of the solid product to hydrocinnamic acid in step A4 is 1:(0.05-0.15).

7. The high performance and high thermal conductivity plastic according to claim 1, characterized in that: The flame retardant is one or more of a halogen flame retardant, a metal hydroxide flame retardant, a phosphorus flame retardant, and a nitrogen flame retardant.

8. The high performance and high thermal conductivity plastic according to claim 1, characterized in that: The glass fiber has a diameter of 10-20 μm and a length of 0.2-1 mm.

9. The high performance and high thermal conductivity plastic according to claim 1, characterized in that: The antioxidant is selected from one or more of hindered phenols, phosphites, thioesters, benzofurans, and hydroxylamine antioxidants.

10. A method for preparing the high performance and high thermal conductivity plastic according to any one of claims 1 to 9, characterized in that: The process comprises the following steps: firstly, pre-treating the thermal conductive filler with glass fiber and coupling agent by ball milling, and then melt-blending and extruding with nylon resin, flame retardant and antioxidant, and extruding the twin-screw at a temperature of 250-280°C and a rotation speed of 200-400 rpm to obtain a high-performance and high-thermal-conductivity plastic.