A heat-conducting filler, a heat-conducting PES composite material and a preparation method thereof

Abstract

This invention discloses a thermally conductive filler, a thermally conductive PES composite material, and their preparation method. The preparation method of the thermally conductive filler includes: adding cobalt salt, iron salt, and sodium acetate to an organic solvent, mixing them evenly, and then heating to react to obtain cobalt ferrite; adding cobalt ferrite, tungsten carbide, and gallic acid to an ethanol aqueous solution, mixing them evenly, and then heating to react to obtain the thermally conductive filler. The above-mentioned thermally conductive filler is added to the thermally conductive PES composite material. Cobalt ferrite is deposited on the surface of tungsten carbide, thereby reducing the gaps between tungsten carbide particles and improving its thermal conductivity. Furthermore, due to the magnetic properties of cobalt ferrite, the thermally conductive filler can be directionally distributed in the PES matrix, forming an ordered thermally conductive pathway, thereby improving the thermal conductivity of the PES composite material. In addition, the phenyl groups on the gallic acid molecules are adsorbed onto tungsten carbide through π-π interactions, further improving the thermal conductivity and dispersibility of the thermally conductive filler. Thus, the thermal conductivity of the PES composite material is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a thermally conductive filler, a thermally conductive PES composite material, and a method for preparing the same. Background Technology

[0002] Polyethersulfone (PES) is a high-performance thermoplastic engineering plastic with excellent heat resistance, physical and mechanical properties, and chemical stability. For example, PES has a high glass transition temperature (Tg), typically above 220°C, maintaining good dimensional stability and mechanical properties even at high temperatures. Furthermore, PES possesses excellent dielectric and insulating properties, maintaining good electrical stability even in high-temperature and humid environments. Its superior properties have led to its widespread application in many fields, such as: in the electronics and electrical industry, it is used to manufacture insulating materials and housings for electronic components like connectors, switches, and capacitors; in the medical device industry, it is used to manufacture components for surgical instruments, implants, and blood processing equipment; and in the automotive industry, it is used to manufacture engine parts, fuel system components, and electrical components.

[0003] However, in certain application areas, such as the electronics and electrical engineering field, the increasing integration and power density of electronic components place higher demands on the thermal conductivity of materials. Ordinary polyethersulfone materials have relatively low thermal conductivity, typically below 0.2 W / (m·K), which limits their use in applications requiring efficient heat dissipation. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a thermally conductive PES composite material and its preparation method. This invention improves the thermal conductivity of PES by adding specific thermally conductive fillers.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] The first objective of this invention is to provide a method for preparing a thermally conductive filler, which includes the following steps:

[0007] S1. Cobalt salt, iron salt, and sodium acetate are added to an organic solvent, mixed evenly, and heated to react. After filtration, washing, and drying, cobalt ferrite is obtained.

[0008] S2. Add the cobalt ferrite, tungsten carbide, and gallic acid prepared in step S1 to an ethanol aqueous solution, mix evenly, heat to react, and then filter, wash, and dry to obtain a gallic acid / cobalt ferrite / tungsten carbide type thermally conductive filler.

[0009] In a further embodiment, in step S1, the mass ratio of cobalt salt, iron salt, and sodium acetate is (18-24):(28-32):(20-24).

[0010] In a further embodiment, in step S1, the cobalt salt is cobalt nitrate, cobalt phosphate, cobalt sulfate, or cobalt chloride;

[0011] The iron salt is ferric nitrate, ferric phosphate, ferric sulfate, or ferric chloride;

[0012] The organic solvent is an aqueous solution of ethanol, isopropanol, glycerol, or acetone;

[0013] The heating reaction is carried out at a temperature of 50-70℃ for 8-12 hours.

[0014] In a further embodiment, in step S2, the mass ratio of tungsten carbide, cobalt ferrite, and gallic acid is (30-40):(20-24):(20-30).

[0015] In a further embodiment, in step S2, the heating reaction is carried out at a temperature of 60-70℃ for 10-18 hours.

[0016] The second objective of this invention is to provide a thermally conductive filler prepared by the above-described preparation method.

[0017] A third objective of this invention is to provide a thermally conductive PES composite material, which is made of the following components in parts by weight:

[0018] PES 93-103 copies,

[0019] 10-16 parts of thermally conductive filler

[0020] Antioxidant 0.1-0.5 parts;

[0021] The thermally conductive filler is the thermally conductive filler described above.

[0022] In a further embodiment, the antioxidant is at least one of tris(2,4-di-tert-butyl)phosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxyphenyl)benzene.

[0023] The fourth objective of this invention is to provide a method for preparing the aforementioned thermally conductive PES composite material, comprising the following steps:

[0024] (1) Weigh 93-103 parts of PES, 10-16 parts of thermally conductive filler, and 0.1-0.5 parts of antioxidant and mix them evenly to obtain a mixture;

[0025] (2) The mixture obtained in step (1) is extruded and granulated from a twin-screw extruder to obtain the thermally conductive PES composite material.

[0026] In a further embodiment, the twin-screw extruder includes six temperature zones arranged in sequence, with the following temperatures: Zone 1: 290–330°C; Zone 2: 310–350°C; Zone 3: 310–350°C; Zone 4: 310–350°C; Zone 5: 310–350°C; Zone 6: 310–350°C; Die head: 310–350°C; and screw speed: 200–280 r / min.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) In this application, cobalt salt, iron salt and sodium acetate are reacted to produce cobalt ferrite, and the chemical equation is as follows:

[0029] CH3COONa + H2O → NaOH + CH3COOH

[0030] Fe 3+ +Co 2+ +8OH - →2FeOOH + 2H₂ + Co(OH)₂

[0031] Co(OH)₂ + 2FeOOH → 2H₂O + CoFe₂O₄

[0032] Sodium acetate is a weak base, and its aqueous solution has a certain buffering capacity, which can stabilize the pH value of the reaction system. In the preparation of cobalt ferrite, a stable pH value helps to control the reaction process and ensure the purity and crystallinity of the product.

[0033] (2) The main component of the thermally conductive filler prepared in this invention is tungsten carbide (WC), which has the characteristics of high hardness, high wear resistance and high thermal conductivity. However, there are certain gaps between the tungsten carbide particles, which will affect the efficiency of heat conduction. Therefore, this invention deposits pre-prepared cobalt ferrite on the surface of tungsten carbide to reduce the gaps between the tungsten carbide particles and achieve the purpose of improving the heat conduction efficiency. Furthermore, since cobalt ferrite itself has a certain magnetic property, it can allow the thermally conductive filler to be oriented and distributed in the PES matrix, forming an orderly thermal conduction path, thereby improving the thermal conductivity of the PES composite material.

[0034] (3) In this invention, gallic acid is added. Since the phenyl groups on the gallic acid molecules are adsorbed onto tungsten carbide through π-π interactions, the attached gallic acid can directly form weak interactions between tungsten carbide particles, further improving the thermal conductivity of the thermally conductive filler.

[0035] In addition, gallic acid itself contains catechol groups, which improves the interfacial compatibility between PES and thermally conductive fillers, making it well dispersed in the PES matrix and less prone to agglomeration.

[0036] In summary, the thermal conductivity of the gallic acid / cobalt ferrite / tungsten carbide type thermally conductive filler prepared by this invention is better than that of ordinary tungsten carbide. Detailed Implementation

[0037] To facilitate understanding of the present invention, a more comprehensive description of the invention will be provided below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure of the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0039] The raw materials used in the following examples are as follows:

[0040] Polyethersulfone (model 3300), Solvay, USA; Cobalt nitrate, Wuhan Kanos Technology Co., Ltd.; Sodium acetate, Langfang Chengpeng Chemical Co., Ltd.; Ethanol, Jinan Mingxin Chemical Co., Ltd.; Deionized water, Shanghai Lanyi Environmental Protection Technology Co., Ltd.; Tungsten carbide, Chengdu Zhongpeng Chemical Co., Ltd.; Gallic acid, Shenzhen Lefu Biotechnology Co., Ltd.; Antioxidants (models Irganox 168, Irganox 1010, Irganox 1330), BASF, Germany.

[0041] The reagents described above are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to provide full disclosure, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0042] Preparation Example 1

[0043] S1. Mix 180g cobalt nitrate, 280g ferric nitrate, 200g sodium acetate, 600g ethanol, and 800g deionized water in a four-necked flask. React at 50°C for 8 hours. After filtration, washing, and drying in a vacuum drying oven at 50°C for 6 hours, cobalt ferrite is obtained.

[0044] S2. 300g of tungsten carbide, 200g of cobalt ferrite, 200g of gallic acid, 600g of ethanol and 700g of deionized water are placed in a four-necked flask and mixed evenly. The mixture is then placed at 60℃ for 10h. After filtration, washing and drying in a vacuum drying oven at 70℃ for 12h, the thermally conductive filler M1 of gallic acid / cobalt ferrite / tungsten carbide type is obtained.

[0045] Example 1

[0046] (1) Weigh 93 parts of PES, 10 parts of thermally conductive filler M1 and 0.1 parts of Irganox168, mix and stir evenly to obtain a mixture;

[0047] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material P1.

[0048] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 290℃, Zone 2 temperature 310℃, Zone 3 temperature 310℃, Zone 4 temperature 310℃, Zone 5 temperature 310℃, Zone 6 temperature 310℃, Die head temperature 310℃, and screw speed 200r / min.

[0049] Preparation Example 2

[0050] S1. Mix 240g cobalt phosphate, 320g ferric phosphate, 240g sodium acetate, 700g isopropanol and 1.2kg deionized water in a four-necked flask and react at 70℃ for 12h. After filtration, washing and drying in a vacuum drying oven at 70℃ for 12h, cobalt ferrite is obtained.

[0051] S2. 400g of tungsten carbide, 240g of cobalt ferrite, 300g of gallic acid, 700g of ethanol and 900g of deionized water are placed in a four-necked flask and mixed evenly. The mixture is then placed at 70℃ for 18h. After filtration, washing and drying in a vacuum drying oven at 80℃ for 18h, the thermally conductive filler M2 of gallic acid / cobalt ferrite / tungsten carbide type is obtained.

[0052] Example 2

[0053] (1) Weigh 103 parts of PES, 16 parts of thermally conductive filler M2, 0.1 parts of Irganox168, 0.2 parts of Irganox1010, and 0.2 parts of Irganox1330, mix and stir evenly to obtain a mixture;

[0054] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material P2.

[0055] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 330℃, Zone 2 temperature 350℃, Zone 3 temperature 350℃, Zone 4 temperature 350℃, Zone 5 temperature 350℃, Zone 6 temperature 350℃, Die head temperature 350℃, and screw speed 280r / min.

[0056] Preparation Example 3

[0057] S1. Mix 210g cobalt sulfate, 300g ferric sulfate, 220g sodium acetate, 650g acetone, and 1.0kg deionized water in a four-necked flask. React at 60℃ for 10 hours. After filtration, washing, and drying in a vacuum drying oven at 60℃ for 9 hours, cobalt ferrite is obtained.

[0058] S2. 350g of tungsten carbide, 220g of cobalt ferrite, 250g of gallic acid, 650g of ethanol and 800g of deionized water are placed in a four-necked flask and mixed evenly. The mixture is then placed at 65℃ for 14 hours. After filtration and washing, the reaction solution is dried in a vacuum drying oven at 75℃ for 15 hours to obtain gallic acid / cobalt ferrite / tungsten carbide type thermally conductive filler M3.

[0059] Example 3

[0060] (1) Weigh 98 parts of PES, 13 parts of thermally conductive filler M3, 0.1 parts of Irganox168, and 0.2 parts of Irganox1010, mix and stir evenly to obtain a mixture;

[0061] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material P3.

[0062] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 310℃, Zone 2 temperature 330℃, Zone 3 temperature 330℃, Zone 4 temperature 330℃, Zone 5 temperature 330℃, Zone 6 temperature 330℃, Die head temperature 330℃, and screw speed 240r / min.

[0063] Preparation Example 4

[0064] S1. 205g cobalt chloride, 315g ferric chloride, 225g sodium acetate, 635g glycerol and 1.05kg deionized water were placed in a four-necked flask and mixed evenly. The mixture was then reacted at 68℃ for 11h. After filtration, washing and drying in a vacuum drying oven at 68℃ for 7.5h, cobalt ferrite was obtained.

[0065] S2. 333g of tungsten carbide, 235g of cobalt ferrite, 285g of gallic acid, 666g of ethanol, and 888g of deionized water were placed in a four-necked flask and mixed evenly. The mixture was then placed at 68℃ for 17h. After filtration, washing, and drying in a vacuum drying oven at 73℃ for 14h, the gallic acid / cobalt ferrite / tungsten carbide type thermally conductive filler M4 was obtained.

[0066] Example 4

[0067] (1) Weigh 95 parts of PES, 15 parts of thermally conductive filler M4, 0.1 parts of Irganox1010, and 0.2 parts of Irganox1330, mix and stir evenly to obtain a mixture;

[0068] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material P4.

[0069] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 295℃, Zone 2 temperature 335℃, Zone 3 temperature 335℃, Zone 4 temperature 335℃, Zone 5 temperature 335℃, Zone 6 temperature 335℃, Die head temperature 335℃, and screw speed 255r / min.

[0070] Preparation Example 5

[0071] S1. 228g cobalt nitrate, 295g ferric nitrate, 235g sodium acetate, 655g ethanol and 1.15kg deionized water were placed in a four-necked flask and mixed evenly. The mixture was then reacted at 58℃ for 11.5h. After filtration, washing and drying in a vacuum drying oven at 66℃ for 7h, cobalt ferrite was obtained.

[0072] S2. 333g of tungsten carbide, 228g of cobalt ferrite, 233g of gallic acid, 652g of ethanol, and 765g of deionized water were placed in a four-necked flask and mixed evenly. The mixture was then placed at 63℃ for 13 hours. After filtration, washing, and drying in a vacuum drying oven at 76℃ for 14 hours, the gallic acid / cobalt ferrite / tungsten carbide type thermally conductive filler M5 was obtained.

[0073] Example 5

[0074] (1) Weigh 100 parts of PES, 13.5 parts of thermally conductive filler M5, 0.2 parts of Irganox1010, and 0.2 parts of Irganox1330, mix and stir evenly to obtain a mixture;

[0075] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material P5.

[0076] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 325℃, Zone 2 temperature 345℃, Zone 3 temperature 345℃, Zone 4 temperature 345℃, Zone 5 temperature 345℃, Zone 6 temperature 345℃, Die head temperature 345℃, and screw speed 270r / min.

[0077] Comparative Example 1

[0078] (1) Weigh 100 parts of PES, 0.2 parts of Irganox1010 and 0.2 parts of Irganox1330, mix and stir evenly to obtain a mixture;

[0079] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material D1.

[0080] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 250℃, Zone 2 temperature 295℃, Zone 3 temperature 295℃, Zone 4 temperature 295℃, Zone 5 temperature 295℃, Zone 6 temperature 295℃, Die head temperature 295℃, and screw speed 270r / min.

[0081] Comparative Example 2

[0082] (1) Weigh 100 parts of PES, 13.5 parts of tungsten carbide, 0.2 parts of Irganox1010, and 0.2 parts of Irganox1330, mix and stir evenly to obtain a mixture;

[0083] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material D2.

[0084] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 250℃, Zone 2 temperature 295℃, Zone 3 temperature 295℃, Zone 4 temperature 295℃, Zone 5 temperature 295℃, Zone 6 temperature 295℃, Die head temperature 295℃, and screw speed 270r / min.

[0085] Comparative Example 3

[0086] (1) Weigh 100 parts of PES, 11.5 parts of tungsten carbide, 2.5 parts of cobalt ferrite, 0.2 parts of Irganox1010, and 0.2 parts of Irganox1330, mix and stir evenly to obtain a mixture;

[0087] (2) The mixture obtained in step (1) is extruded and granulated to obtain PES composite material D2.

[0088] The temperatures and screw speeds of the twin-screw extruder in each zone are as follows: Zone 1 temperature 250℃, Zone 2 temperature 295℃, Zone 3 temperature 295℃, Zone 4 temperature 295℃, Zone 5 temperature 295℃, Zone 6 temperature 295℃, Die head temperature 295℃, and screw speed 270r / min.

[0089] The performance data of the PES composite materials prepared in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1 below:

[0090] Table 1

[0091] Test Project Test Standards unit P1 P2 P3 P4 P5 D1 D2 D3 thermal conductivity ASTM D5470 W / m·K 3.68 3.72 3.59 3.66 3.71 0.35 1.98 2.23

[0092] As can be seen from the table above, the PES composite materials P1-P5 prepared by this invention have excellent thermal conductivity, all reaching above 3.59, which meets the requirements for high thermal conductivity of materials in specific fields such as electronics and electrical engineering.

[0093] Compared with Comparative Example 1, Example 5 incorporated the thermally conductive filler prepared in this invention, resulting in a significantly higher thermal conductivity of the PES composite material P5 compared to D1.

[0094] Compared with Comparative Example 2, the addition of the thermally conductive filler prepared in this invention significantly improved the thermal conductivity of the PES composite material in Example 5, and it was even better than the thermal conductivity of PES composite material D2 with tungsten carbide added alone. This is because although tungsten carbide itself has high thermal conductivity, there are certain gaps between tungsten carbide particles, which affect the efficiency of heat conduction. In this invention, cobalt ferrite is deposited on the surface of tungsten carbide, thereby reducing the gaps between tungsten carbide particles and improving the efficiency of heat conduction. Furthermore, cobalt ferrite itself has a certain degree of magnetism, which allows the thermally conductive filler to be oriented and distributed in the PES matrix, forming an orderly thermal conduction pathway, thereby improving the thermal conductivity of the PES composite material.

[0095] Compared with Comparative Example 3, the addition of the thermally conductive filler prepared in this invention in Example 5 significantly improved the thermal conductivity of the PES composite material, and it was even better than the thermal conductivity of PES composite material D3, which only added tungsten carbide and cobalt ferrite. This is because the phenyl groups on the gallic acid molecules are adsorbed onto the tungsten carbide through π-π interactions. The attached gallic acid can directly form weak interactions between the tungsten carbide particles, further improving the thermal conductivity of the thermally conductive filler. In addition, gallic acid itself contains catechol groups, which improve the interfacial compatibility between PES and the thermally conductive filler, making it well dispersed in the PES matrix and less prone to agglomeration.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method of making a thermally conductive filler, characterized by: Includes the following steps: S1. Cobalt salt, iron salt, and sodium acetate are added to an organic solvent, mixed evenly, and heated to react. After filtration, washing, and drying, cobalt ferrite is obtained. S2. Add the cobalt ferrite, tungsten carbide, and gallic acid prepared in step S1 to an ethanol aqueous solution, mix evenly, heat to react, and then filter, wash, and dry to obtain a gallic acid / cobalt ferrite / tungsten carbide type thermally conductive filler.

2. The method of claim 1, wherein: In step S1, the mass ratio of cobalt salt, iron salt and sodium acetate is (18-24):(28-32):(20-24).

3. The method of claim 1, wherein: In step S1, the cobalt salt is cobalt nitrate, cobalt phosphate, cobalt sulfate, or cobalt chloride; The iron salt is ferric nitrate, ferric phosphate, ferric sulfate, or ferric chloride; The organic solvent is an aqueous solution of ethanol, isopropanol, glycerol, or acetone; The heating reaction is carried out at a temperature of 50-70℃ for 8-12 hours.

4. The preparation method according to claim 1, characterized in that: In step S2, the mass ratio of tungsten carbide, cobalt ferrite, and gallic acid is (30-40):(20-24):(20-30).

5. The preparation method according to claim 1, characterized in that: In step S2, the heating reaction is carried out at a temperature of 60-70℃ for 10-18 hours.

6. A thermally conductive filler, characterized in that: It is prepared by the preparation method described in any one of claims 1-5.

7. A thermally conductive PES composite material, characterized in that: It is made from the following components in parts by weight: PES 93-103 copies, 10-16 parts of thermally conductive filler Antioxidant 0.1-0.5 parts; The thermally conductive filler is the thermally conductive filler as described in claim 6.

8. The thermally conductive PES composite material according to claim 7, characterized in that: The antioxidant is at least one of tris(2,4-di-tert-butyl)phosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxyphenyl)benzene.

9. A method for preparing a thermally conductive PES composite material as described in claim 7 or 8, characterized in that: Includes the following steps: (1) Weigh 93-103 parts of PES, 10-16 parts of thermally conductive filler, and 0.1-0.5 parts of antioxidant and mix them evenly to obtain a mixture; (2) The mixture obtained in step (1) is extruded and granulated from a twin-screw extruder to obtain the thermally conductive PES composite material.

10. The preparation method according to claim 9, characterized in that: The twin-screw extruder includes six temperature zones arranged in sequence, with the following temperatures: Zone 1: 290–330℃; Zone 2: 310–350℃; Zone 3: 310–350℃; Zone 4: 310–350℃; Zone 5: 310–350℃; Zone 6: 310–350℃; Die head: 310–350℃; and screw speed: 200–280 r / min.