Self-repairing heat-conducting adhesive as well as preparation and application thereof
By using multiple heating reactions of lipoic acid, N,N`-methylenebisacrylamide, aluminum chloride and thermal fillers in thermal adhesives, a covalent polymer network and dynamic crosslinking network are formed, and the thermal adhesive is thermally conductive. The problem of unbalanced performance and bonding performance has realized the self-repair function and improved the service life of electronic equipment.
Patent Information
- Application Number
- CN202411352546.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-01-03
AI Technical Summary
While improving thermal conductivity, existing thermal adhesives have poor bonding performance, and high filler content leads to uneven accumulation of fillers, causing cracks inside the substrate, unable to heal themselves, hindering heat transfer, and reducing the service life of electronic equipment.
Lipoic acid, N,N`-methylenebisacrylamide, aluminum chloride and thermal filler are used to carry out multiple heating reactions under mild reaction conditions to form a covalent polymer network, and the metal coordination between Al3+ and lipoic acid is coordinated. Build a dynamic crosslinking network to realize self-healing function.
The balance between thermal conductivity and adhesive properties is achieved, the preparation process is simplified, the requirements of reaction conditions are reduced, and the adhesive is given self-healing ability, which improves the service life of electronic equipment.
Smart Images
Figure CN119242255A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of heat conduction technology, and in particular relates to a self-repairing heat-conducting adhesive and a preparation method and application thereof. Background Art
[0002] Thermally conductive adhesive is a composite material composed of thermally conductive fillers and polymer adhesives. In order to ensure the high thermal conductivity of thermally conductive adhesives, the content of thermally conductive fillers in thermally conductive adhesives is very high. The high proportion of thermally conductive fillers and the low proportion of adhesives make it have good thermal conductivity but poor bonding performance, and the thermal conductivity and bonding performance cannot be balanced. At the same time, adding a high filler content to improve the performance of thermally conductive adhesives may cause the fillers to aggregate unevenly in the adhesive matrix, resulting in uneven heating inside the matrix, thereby causing cracks inside the matrix. Cracks that cannot heal themselves will seriously hinder the effective transfer of heat, causing heat accumulation and reducing the service life of electronic equipment.
[0003] Patent CN118185011A discloses a composite elastomer and its preparation method, wherein the dissolved carboxyl-containing compound reacts with metal ions at 150-180°C for 5-20 minutes to obtain the composite elastomer. The preparation process of this patent is complicated, requiring a certain reaction time at a specific temperature, and involves the reaction of carboxyl-containing compounds with metal ions, which has high requirements for reaction conditions. At the same time, the balance between thermal conductivity and adhesive properties of the elastomer needs to be optimized, and it basically does not have self-repairing function. Summary of the invention
[0004] The purpose of the present invention is to provide a self-healing adhesive and a preparation method thereof to achieve an excellent comprehensive balance of thermal conductivity, bonding and self-healing properties.
[0005] The purpose of the present invention can be achieved by the following technical solutions:
[0006] In a first aspect, the present invention provides a method for preparing a self-healing thermally conductive adhesive, wherein lipoic acid is placed in an inert atmosphere, subjected to a first heating reaction, and a light yellow solution is obtained. The solution is then added to N,N'-methylenebisacrylamide and subjected to a second heating reaction. Aluminum chloride and a thermally conductive filler are then added in sequence, subjected to a third heating reaction, and the adhesive product is obtained after cooling.
[0007] Furthermore, the mass ratio of lipoic acid, N,N'-methylenebisacrylamide, aluminum chloride and thermal conductive filler is 1: (0.4-0.6): (0.008-0.012): (0.17-0.7).
[0008] Furthermore, the mass of the thermally conductive filler accounts for 10%-30% of the total mass of the adhesive.
[0009] Furthermore, the thermally conductive filler is one of aluminum oxide, boron nitride and aluminum nitride.
[0010] Furthermore, the gas in the inert atmosphere is nitrogen or argon.
[0011] Furthermore, the reaction temperature of the first heating reaction is 100-200° C., and the reaction time is 5-15 min.
[0012] Furthermore, the reaction temperature of the second heating reaction is 100-200° C., and the reaction time is 3-5 min.
[0013] Furthermore, the reaction temperature of the third heating reaction is 100-200° C., and the reaction time is 3-5 min.
[0014] In a second aspect, the present invention provides a self-healing thermally conductive adhesive, which is prepared by the preparation method as described in any one of the above items.
[0015] In a third aspect, the present invention provides an application of a self-healing thermally conductive adhesive in bonding of electronic devices.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] (1) The preparation method adopted by the present invention has simple steps and mild reaction conditions.
[0018] (2) The present invention constructs a covalent polymer network by ring-opening lipoic acid at 150°C to form a linear long chain, and then quenching the terminal free radicals with the double bonds in the N,N'-methylenebisacrylamide molecule through reverse vulcanization. In addition, the addition of AlCl3 and thermally conductive fillers further stabilizes the thermally conductive adhesive network. Al 3+ Metal coordination with the carboxyl group in the lipoic acid molecule enhances the stability of the polymer network and plays a role in dynamic cross-linking, making the cross-linked network have self-repairing function.
[0019] (3) The present invention introduces the thermally conductive filler by firmly locking it when forming a polymer network and constructing a thermally conductive network at the same time, thereby producing an adhesive with thermal conductivity and self-healing functions. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The thermal conductivity of each embodiment with different fillers and different filling amounts;
[0021] Figure 2 This is a diagram of the self-healing process of the self-healing thermal conductive adhesive prepared in the present invention under a microscope. DETAILED DESCRIPTION
[0022] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.
[0023] In the following examples, raw materials or processing techniques, unless otherwise specified, are conventional commercially available raw materials or conventional processing techniques in the art.
[0024] Example 1
[0025] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0026] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0027] (3) Add 0.01 g of aluminum chloride to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0028] Example 2
[0029] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0030] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0031] (3) Add 0.01 g of aluminum chloride and 10% (0.17 g) of aluminum oxide to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0032] Example 3
[0033] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0034] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0035] (3) Add 0.01 g of aluminum chloride and 20% (0.4 g) of aluminum oxide to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0036] Example 4
[0037] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0038] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0039] (3) Add 0.01 g of aluminum chloride and 30% (0.7 g) of aluminum oxide to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0040] Example 5
[0041] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0042] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0043] (3) Add 0.01 g of aluminum chloride and 10% (0.17 g) of aluminum nitride (AlN) to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0044] Example 6
[0045] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0046] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0047] (3) Add 0.01 g of aluminum chloride and 20% (0.4 g) of aluminum nitride to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0048] Example 7
[0049] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0050] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0051] (3) Add 0.01 g of aluminum chloride and 30% (0.7 g) of aluminum nitride to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0052] Example 8
[0053] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0054] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0055] (3) Add 0.01 g of aluminum chloride and 10% (0.17 g) of boron nitride to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0056] Example 9
[0057] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0058] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0059] (3) Add 0.01 g of aluminum chloride and 20% (0.4 g) of boron nitride (BN) to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0060] Example 10
[0061] (1) 1 g of lipoic acid was added to a three-necked flask, and nitrogen was purged into the system to remove oxygen. The flask was then heated to 150°C for 10 minutes to obtain a light yellow solution.
[0062] (2) 0.5 g of N,N'-methylenebisacrylamide was added to the obtained yellow solution and heated at 150°C for 5 minutes to obtain a precursor.
[0063] (3) Add 0.01 g of aluminum chloride and 30% (0.7 g) of boron nitride to the obtained precursor, heat at 150° C. for 5 minutes, and cool to room temperature to obtain a self-healing thermally conductive adhesive.
[0064] from Figure 1 It can be seen that the thermal conductivity of the adhesive increases with the increase of the filling amount, and the adhesive with aluminum nitride added has better thermal conductivity than other fillers.
[0065] Figure 2 The figure shows the self-repairing process of a thermally conductive adhesive with an aluminum nitride filling content of 30% (ie, Example 7) under a microscope after being gently scratched with a scalpel, with each observation interval of 30 minutes, as shown in Figures a to d. It can be seen that the synthesized thermally conductive adhesive has a certain self-repairing ability.
[0066] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.
Claims
1. A method for preparing a self-repairing thermally conductive adhesive, characterized in that: The lipoic acid is placed in an inert atmosphere and subjected to a first heating reaction to obtain a light yellow solution, which is then added to N,N'-methylenebisacrylamide and subjected to a second heating reaction. Aluminum chloride and a thermal conductive filler are then added in sequence and subjected to a third heating reaction. The adhesive product is obtained after cooling.
2. The method for preparing a self-repairing thermally conductive adhesive according to claim 1, characterized in that: The mass ratio of lipoic acid, N,N'-methylenebisacrylamide, aluminum chloride and thermal conductive filler is 1: (0.4-0.6): (0.008-0.012): (0.17-0.7).
3. A method for preparing a self-repairing thermally conductive adhesive according to claim 1 or 2, characterized in that: The mass of the thermal conductive filler accounts for 10%-30% of the total mass of the adhesive.
4. The method for preparing a self-repairing thermally conductive adhesive according to claim 1, characterized in that: The thermal conductive filler is one of aluminum oxide, boron nitride and aluminum nitride.
5. The method for preparing a self-repairing thermally conductive adhesive according to claim 1, characterized in that: The gas providing the inert atmosphere is nitrogen or argon.
6. The method for preparing a self-repairing thermally conductive adhesive according to claim 1, characterized in that: The reaction temperature of the first heating reaction is 100-200°C, and the reaction time is 5-15 minutes.
7. The method for preparing a self-repairing thermally conductive adhesive according to claim 1, characterized in that: The reaction temperature of the second heating reaction is 100-200°C, and the reaction time is 3-5 minutes.
8. The method for preparing a self-repairing thermally conductive adhesive according to claim 1, characterized in that: The reaction temperature of the third heating reaction is 100-200° C., and the reaction time is 3-5 min.
9. A self-repairing thermally conductive adhesive, prepared by the preparation method according to any one of claims 1 to 8.
10. Use of the self-repairing thermally conductive adhesive as claimed in claim 9 in bonding of electronic equipment.