Preparation method of gradient modulus adaptive damping material and application thereof in vibration protection of precision parts

Abstract

The application relates to a preparation method of a gradient modulus adaptive damping material and application of the gradient modulus adaptive damping material in vibration protection of precise components, and belongs to the field of damping materials. The method comprises the following steps: bottom layer hard and middle layer slightly soft viscoelastic material preparation: uniformly mixing polyurethane acrylate, tetra (3-mercaptopropionic acid) pentaerythritol ester and tripropylene glycol diacrylate, adding triethylamine and slowly stirring; the amount of the middle layer curing agent is reduced by 25 wt.% relative to the bottom; top layer soft viscoelastic material preparation: uniformly mixing polyurethane acrylate, tetra (3-mercaptopropionic acid) pentaerythritol ester and hydroxyethyl acrylate, adding triethylamine and slowly stirring; pouring the bottom layer hard viscoelastic material to realize semi-curing, pouring the middle layer slightly soft viscoelastic material to realize semi-curing, and pouring the top layer soft viscoelastic material to completely cure. Through a three-dimensional synergistic mechanism of gradient modulus, interface strengthening and dynamic response, the application breaks through the rigid-flex mismatch and energy dissipation efficiency bottleneck of the existing material in microstructure protection.

Description

Technical Field

[0001] This invention belongs to the field of damping materials, specifically relating to a method for preparing a gradient modulus adaptive damping material and its application in vibration protection of precision components. Background Technology

[0002] With the rapid development of precision electronics, aerospace, and biomedical equipment, vibration and shock protection places higher demands on material performance. Statistics show that global losses due to microstructure failures caused by vibration exceed hundreds of billions of US dollars annually. This is especially true in precision devices such as semiconductor chips and optical components, where surface micro-features (e.g., pads, probes) are extremely sensitive to vibration: even micrometer-level vibrations can trigger signal distortion or crack propagation. Traditional homogenized damping materials suffer from fundamental flaws—they are prone to resonance under high-frequency impacts and damping saturation under low-frequency vibrations, making it difficult to balance the contradictory requirements of stiffness and flexibility.

[0003] While existing gradient modulus damping materials alleviate this contradiction through modulus gradient design, these materials primarily employ multiphase composite processes (such as hot pressing and co-precipitation) to construct a modulus gradient structure from the surface to the substrate, attempting to resolve the rigidity-flexibility contradiction inherent in traditional homogeneous materials. For instance, researchers often use hot pressing to disperse high-elasticity modulus particles (such as rubber particles) within a polymer matrix, achieving modulus gradients by adjusting the particle concentration.

[0004] While these methods can reduce vibration transmissibility to some extent (by 30%-50% compared to homogeneous materials), they still have fundamental drawbacks. First, traditional multiphase composite processes struggle to achieve a continuous modulus gradient distribution. Offline curing methods result in weak interlayer bonding, making them prone to interfacial delamination or stress concentration under dynamic loads, severely impacting the overall material performance. Second, existing gradient materials lack an adaptive response mechanism to impact load frequencies. High-modulus layers are prone to local resonance under high-frequency impacts, while low-frequency vibrations fail to effectively dissipate energy due to damping saturation. Third, the synergistic optimization of surface microstructure protection and material rigidity-flexibility design is insufficient. When impacts act on device surface features (such as pads and probes), traditional buffer layers may deform excessively, leading to substrate deformation or even microcrack propagation. The root cause of these problems lies in the fact that existing materials cannot simultaneously achieve precise control of gradient modulus, dynamic load response, and interface performance optimization. Summary of the Invention

[0005] This invention addresses the limitations of existing gradient modulus damping materials in simultaneously achieving precise control of gradient modulus, dynamic load response, and interface performance optimization. It provides a method for preparing an adaptive gradient modulus damping material and its application in vibration protection of precision components. This invention innovatively overcomes the aforementioned bottlenecks through an in-situ gradient construction technique using a layered curing process: First, a medium-modulus transition layer is introduced during the semi-curing stage of the high-modulus substrate layer, utilizing molecular chain diffusion to form a strong chemical bond interface, significantly improving interlayer bonding strength. Second, by precisely controlling the curing window, the surface-to-substrate modulus is continuously adjustable, allowing for controllable attenuation of stress waves within the gradient structure. Finally, a staged curing process endows the material with frequency-sensitive response characteristics—full-range deformation energy dissipation in the low-frequency range and resonance suppression in the high-frequency range using the high-modulus substrate. This solves the problems of interface defects, frequency desensitization, and microstructure protection failure in traditional gradient materials.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a gradient modulus adaptive damping material, the method comprising:

[0008] Step 1: Preparation of the underlying rigid viscoelastic material: Mix polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and tripropylene glycol diacrylate evenly, remove bubbles, add triethylamine catalyst, stir slowly, and set aside for use.

[0009] Step 2: Preparation of the slightly soft viscoelastic intermediate layer: Polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and tripropylene glycol diacrylate are mixed evenly, degassed, and triethylamine catalyst is added. The mixture is stirred slowly and set aside. In Step 2, the amount of pentaerythritol tetrakis(3-mercaptopropionic acid) is reduced by 25 wt.% compared to Step 1.

[0010] Step 3: Preparation of the top layer soft viscoelastic material: Mix polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and hydroxyethyl acrylate evenly, remove bubbles, add triethylamine catalyst, stir slowly, and set aside for use;

[0011] Step 4: Preparation of in-situ gradient damping material: First, pour the bottom layer of rigid viscoelastic material from Step 1 into the mold to achieve semi-curing of the bottom layer. Then, pour the middle layer of slightly softer viscoelastic material on top of this to achieve semi-curing of the middle layer. While the middle layer is semi-curing, the bottom layer will gradually change from semi-cured to fully cured. On top of this, pour the top layer of soft viscoelastic material to achieve complete curing of the three layers of material, so as to achieve entanglement and curing of the molecular chain level into a uniform whole.

[0012] Further, step one specifically involves: stirring polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and tripropylene glycol diacrylate at room temperature for 20 minutes, then placing the mixture in a vacuum oven to thoroughly eliminate air bubbles. The catalyst, triethylamine, is then slowly added to the mixed resin. Because triethylamine is highly volatile, it readily evaporates in the vacuum oven, preventing the system from curing. To avoid air bubble formation, the resin must be stirred as gently and slowly as possible after adding the catalyst.

[0013] Further, in step one, 7g of polyurethane acrylate (CN996), 2.7g–3.6g of pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate (PETMP), 3g of tripropylene glycol diacrylate (TPGDA), and 0.1g of triethylamine (TEA) are used. The polyurethane acrylate serves as the resin matrix, the tripropylene glycol diacrylate acts as an reactive diluent to reduce viscosity and regulate the network, the pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate acts as a curing agent, primarily controlling the degree of polymer crosslinking, and the triethylamine acts as a catalyst.

[0014] Further, in step two, polyurethane acrylate, tripropylene glycol diacrylate, and pentaerythritol tetrakis(3-mercaptopropionic acid) (reduction of 25 wt.%) are stirred at room temperature for 20 minutes. The reduced amount of pentaerythritol tetrakis(3-mercaptopropionic acid) reduces the degree of cross-linking in the polymer network, lowers the material modulus, and increases flexibility. The mixture is then placed in a vacuum oven to thoroughly eliminate air bubbles. The catalyst, triethylamine, is slowly added to the mixed resin. Because triethylamine is highly volatile, it readily evaporates in the vacuum oven, preventing the system from curing. To avoid air bubble formation, the resin must be stirred as gently and slowly as possible after adding the catalyst.

[0015] Further, in step two, 7g of polyurethane acrylate (CN996), 3g of tripropylene glycol diacrylate (TPGDA), and 0.1g of triethylamine (TEA) are used. The polyurethane acrylate serves as the resin matrix, the tripropylene glycol diacrylate acts as an reactive diluent to reduce viscosity and regulate the network, and pentaerythritol tetrakis(3-mercaptopropionic acid) ester is a curing agent, primarily used to regulate the degree of polymer crosslinking. Triethylamine acts as a catalyst.

[0016] Furthermore, in step three, after stirring the polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid), and hydroxyethyl acrylate at room temperature for 20 minutes, the mixture is placed in a vacuum oven to thoroughly eliminate air bubbles. Then, the catalyst triethylamine is slowly added to the mixed resin. Because triethylamine is highly volatile, it easily evaporates in the vacuum oven, preventing the system from curing. To avoid the formation of air bubbles, the resin must be stirred as gently and slowly as possible after adding the catalyst.

[0017] Further, in step three, the following components are used: 8.5g polyurethane acrylate (CN996), 3.2–3.6g pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate (PETMP), 1.5g hydroxyethyl acrylate (HEA), and 0.1g triethylamine (TEA). Polyurethane acrylate serves as the resin matrix, hydroxyethyl acrylate acts as an reactive diluent to reduce viscosity and regulate the network, and is much softer than the material prepared from tripropylene glycol diacrylate. Pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate acts as a curing agent, primarily controlling the degree of polymer crosslinking. Triethylamine acts as a catalyst.

[0018] Further, in step four, the preparation of the in-situ gradient damping material is as follows: First, the bottom layer of rigid viscoelastic material from step one is poured into the mold and left to stand at room temperature for 25 minutes to achieve a semi-cured state. Then, a slightly softer viscoelastic material is poured into the middle layer on top of this, and after another 25 minutes of semi-curing at room temperature, while the middle layer is undergoing semi-curing, the bottom layer will gradually change from semi-cured to fully cured. On top of this, a soft viscoelastic material is poured into the upper layer, and then left to stand at room temperature for 4 hours to allow the three layers of material to be fully cured so as to achieve the entanglement and curing of the molecular chain level into a uniform whole.

[0019] The gradient modulus adaptive damping material prepared by the above method is used for vibration protection of precision components.

[0020] The advantages of this invention over the prior art are as follows:

[0021] 1. The adaptive damping material of the present invention achieves the following core advantages for protective objects with surface protrusions (such as chip pads, sensor probes and other microstructures) through gradient modulus layer design and in-situ curing process: (1) The ultra-low modulus region of the surface layer absorbs impact energy through adaptive deformation, reduces the stress peak at the tip of the protrusion, and avoids plastic deformation or fracture of the microstructure due to local stress concentration; (2) The high modulus region of the bottom layer provides rigid support to prevent the overall deformation caused by the impact load being transmitted to the substrate, and ensures the geometric stability of the protrusion array; The intermediate transition layer disperses the energy transmission path through the stress wave refraction mechanism, and eliminates the stress singularity that is easy to occur at the root of the protrusion in traditional homogeneous materials.

[0022] 2. Process innovation and performance synergy: Achieve continuous modulus gradient (from surface to substrate), and form strong chemical bonding interfaces between layers through molecular chain diffusion, avoiding the interface delamination problem that is prone to occur in traditional multiphase materials;

[0023] 3. Experimental verification and scenario adaptability: This design can be extended to fields such as semiconductor packaging, MEMS devices, and biomedical implants, providing a universal solution for the protection of surface micro-features.

[0024] In summary, this invention overcomes the bottlenecks of rigidity-flexibility mismatch and energy dissipation efficiency in the protection of microstructures by using a three-dimensional synergistic mechanism of gradient modulus-interface reinforcement-dynamic response, providing an innovative technical path for vibration safety protection of precision devices. Attached Figure Description

[0025] Figure 1 Compressive displacement load diagrams for hard and viscoelastic intermediate materials with different curing agent contents;

[0026] Figure 2 Compressive modulus diagrams for hard and intermediate viscoelastic materials with different curing agent contents;

[0027] Figure 3 Compression displacement load diagrams for soft viscoelastic materials with different curing agent contents;

[0028] Figure 4 Compressive modulus diagrams for soft viscoelastic materials with different curing agent contents;

[0029] Figure 5 Optical photograph of in-situ gradient damping material;

[0030] Figure 6 An optical photograph of the in-situ gradient damping material after staining;

[0031] Figure 7 An optical photograph of the in-situ gradient damping material after being combined with the device to be protected;

[0032] Figure 8 An optical photograph of an in-situ gradient damping material subjected to a 500g impact.

[0033] Figure 9 A confocal microscope image of the surface structure of the device to be protected before it is subjected to an impact;

[0034] Figure 10 A confocal microscope image of the surface structure of the device to be protected after it has been subjected to an impact.

[0035] Figure 11 Optical and microscopic images of in-situ gradient damping materials after impact;

[0036] Figure 12 A confocal microscope image of an in-situ gradient damping material before it is subjected to impact.

[0037] Figure 13 This is a confocal microscope image of an in-situ gradient damping material after it has been subjected to impact. Detailed Implementation

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0039] Example 1:

[0040] Preparation of the bottom rigid support layer and the middle softer layer: 7g of polyurethane acrylate (CN996), 2.7g~3.6g of pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP) and 3g of tripropylene glycol diacrylate (TPGDA) were stirred at room temperature for 20 minutes, and then placed in a vacuum oven to completely eliminate air bubbles. Then, 0.1g of triethylamine catalyst was slowly added to the mixed resin, and the mixture was gently stirred to avoid the generation of air bubbles. Finally, the mixture was poured into a compression sample mold.

[0041] Five different compression samples were prepared by using pentaerythritol tetrakis(3-mercaptopropionic acid) curing agent with different contents, and their formulations are shown in Table 1.

[0042] Table 1

[0043]

[0044]

[0045] The sample was subjected to a compressive load test, and its compressive displacement load was as follows: Figure 1 As shown, its compressive modulus is calculated as follows: Figure 2 As shown, the prepared samples have high modulus. Although A-5 has the highest modulus, its compressive displacement is lower than that of A-4, which means that its impact resistance is poor. Considering all factors, the A-4 sample with higher compressive displacement and slightly lower modulus is suitable as the bottom support layer, while the A-1 sample with lower modulus and highest compressive displacement is suitable as the intermediate transition layer.

[0046] Preparation of the top soft transition layer: 8.5g of polyurethane acrylate, 1.5g of pentaerythritol tetrakis(3-mercaptopropionic acid) and 3.2-3.6g of hydroxyethyl acrylate (HEA) were stirred at room temperature for 20 minutes, and then placed in a vacuum oven to completely eliminate air bubbles. Then, 0.1g of triethylamine catalyst was slowly added to the mixed resin, and the mixture was gently stirred to avoid the generation of air bubbles. Finally, the mixture was poured into a compression mold.

[0047] Five different compression samples were prepared by using pentaerythritol tetrakis(3-mercaptopropionic acid) curing agent with different contents, and their formulations are shown in Table 2.

[0048] Table 2

[0049] serial number CN996 HEA PETMP B-1 8.5 1.5 3.2 B-2 8.5 1.5 3.4 B-3 8.5 1.5 3.6

[0050] The sample was subjected to a compressive load test, and its compressive displacement load was as follows: Figure 3 As shown, its compressive modulus is calculated as follows: Figure 4 As shown, the prepared samples have very low moduli, with sample B-3 having the lowest compressive modulus and the largest compressive displacement, making it suitable as the surface layer of a gradient modulus damping material.

[0051] Example 2:

[0052] Step 1: Mix 7g of polyurethane acrylate, 3.6g of pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate, and 3g of tripropylene glycol diacrylate at room temperature for 20 minutes. Then, place the mixture in a vacuum oven to thoroughly eliminate air bubbles. Next, slowly add 0.1g of triethylamine catalyst to the mixed resin, stirring gently to avoid generating air bubbles. Pour the mixture into a mold, filling it to two-fifths of its height. After curing at room temperature for 25 minutes, proceed to the next step to allow it to reach a semi-cured state.

[0053] Step 2: Mix 7g of polyurethane acrylate, 2.7g of pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate, and 3g of tripropylene glycol diacrylate at room temperature for 20 minutes. Then, place the mixture in a vacuum oven to thoroughly eliminate air bubbles. Next, slowly add 0.1g of triethylamine catalyst to the mixed resin, stirring gently to avoid generating air bubbles. Pour the mixture into a mold, filling it to one-fifth of its total volume. After curing for 25 minutes, proceed to the next step to allow it to reach a semi-cured state.

[0054] Step 3: Stir 8.5g of polyurethane acrylate, 1.5g of pentaerythritol tetrakis(3-mercaptopropionic acid) and 3.6g of hydroxyethyl acrylate at room temperature for 20 minutes, then place them in a vacuum oven to fully eliminate air bubbles. Then slowly add 0.1g of triethylamine catalyst to the mixed resin, stirring gently to avoid the formation of air bubbles. Finally, pour the mixture into the mold to fill the entire mold.

[0055] Step 4: Allow to stand for 4 hours to ensure complete curing of the resin throughout the mold, and to allow the molecular chains of the three layers to fully diffuse and solidify into a single unit. The final viscoelastic damping material produced is as follows: Figure 5 As shown.

[0056] The surface of the viscoelastic damping material prepared in Example 2 was marked with dye, such as... Figure 6 As shown. Then, a sample with tiny protrusions on its surface is taken to simulate the device to be protected with the characteristic structure.

[0057] Place the side with the special structure facing down on a viscoelastic damping material, such as... Figure 7 As shown. Then, a pressure of 500g is applied to its upper part to simulate the effect of shock vibration on a device with a complex structure, such as... Figure 8As shown. Then the pressure is removed, and the surface of the viscoelastic damping material at the end of the impact is as follows. Figure 9 As shown, when subjected to impact, the complex surface structure of the device to be protected is completely embedded in the adaptive viscoelastic damping material, giving full play to the flexible deformation characteristics of the surface adaptive layer and avoiding plastic deformation or fracture of the microstructure caused by local stress concentration.

[0058] Laser confocal microscopy was used to test the surface protrusion structure of the simulated protected sample before and after the impact, such as... Figure 9 and Figure 10 As shown, the surface of the sample to be protected did not change after the impact test, and the height remained consistent before and after. The adaptive viscoelastic damping material played a good adaptive deformation protection role and did not cause plastic deformation or various damages to the surface of the protected sample.

[0059] A comprehensive laser confocal test was performed on the simulated protected sample after the impact, such as... Figure 11 As shown, after the impact test, the entire surface of the protected sample, including the surface with complex protrusions and the bottom surface, was stained with blue fuel, indicating that the prepared viscoelastic damping material completely wrapped the surface of the protected device, achieving sufficient protection.

[0060] Laser confocal microscopy tests were performed on the materials before and after impact, as well as on the viscoelastic damping materials, such as... Figure 12 and 13 As shown, after the impact test, the adaptive viscoelastic material fully adapts to the complex structure of the sample surface to be protected, and an embedded pattern of the protected sample's structure appears on the surface.

Claims

1. A method for preparing a gradient modulus adaptive damping material, characterized in that: The method is as follows: Step 1: Preparation of the underlying rigid viscoelastic material: Mix polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and tripropylene glycol diacrylate evenly, remove bubbles, add triethylamine catalyst, stir slowly, and set aside for use. Step 2: Preparation of the slightly softer viscoelastic intermediate layer: Polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate, and tripropylene glycol diacrylate are mixed evenly, degassed, and triethylamine catalyst is added. The mixture is stirred slowly and set aside. In Step 2, the amount of pentaerythritol tetrakis(3-mercaptopropionic acid) acrylate used is reduced by 25 wt.% compared to Step 1. Step 3: Preparation of the top layer soft viscoelastic material: Mix polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and hydroxyethyl acrylate evenly, remove bubbles, add triethylamine catalyst, stir slowly, and set aside for use; Step 4: Preparation of in-situ gradient damping material: First, pour the bottom layer of rigid viscoelastic material from Step 1 into the mold to achieve semi-curing of the bottom layer. Then, pour the middle layer of slightly softer viscoelastic material on this basis to achieve semi-curing of the middle layer. Finally, pour the top layer of soft viscoelastic material on this basis to achieve complete curing of the three layers.

2. The method for preparing a gradient modulus adaptive damping material according to claim 1, characterized in that: Step one specifically involves: stirring polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and tripropylene glycol diacrylate at room temperature for 20 minutes, then placing them in a vacuum oven to fully eliminate air bubbles, slowly adding the catalyst triethylamine to the mixed resin, and then slowly stirring the resin after adding the catalyst.

3. The method for preparing a gradient modulus adaptive damping material according to claim 1 or 2, characterized in that: In step one, 7 g of polyurethane acrylate, 2.7 g to 3.6 g of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, 3 g of tripropylene glycol diacrylate, and 0.1 g of triethylamine.

4. The method for preparing a gradient modulus adaptive damping material according to claim 1, characterized in that: In step two, polyurethane acrylate, tripropylene glycol diacrylate and pentaerythritol tetrakis(3-mercaptopropionic acid) (reduction of 25 wt.%) are stirred at room temperature for 20 minutes, placed in a vacuum oven to fully eliminate air bubbles, and the catalyst triethylamine is slowly added to the mixed resin. After the catalyst is added, the resin is slowly stirred.

5. A method for preparing a gradient modulus adaptive damping material according to claim 1 or 4, characterized in that: In step two, 7 g of polyurethane acrylate, 3 g of tripropylene glycol diacrylate, and 0.1 g of triethylamine are used.

6. The method for preparing a gradient modulus adaptive damping material according to claim 1, characterized in that: In step three, polyurethane acrylate, pentaerythritol tetrakis(3-mercaptopropionic acid) and hydroxyethyl acrylate are stirred at room temperature for 20 minutes, then placed in a vacuum oven to fully eliminate air bubbles. Then, the catalyst triethylamine is slowly added to the mixed resin, and the resin is slowly stirred after the catalyst is added.

7. A method for preparing a gradient modulus adaptive damping material according to claim 1 or 6, characterized in that: In step three, there are 8.5 g of polyurethane acrylate, 3.2~3.6 g of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, 1.5 g of hydroxyethyl acrylate, and 0.1 g of triethylamine.

8. The method for preparing a gradient modulus adaptive damping material according to claim 1, characterized in that: In step four, the in-situ gradient damping material is prepared as follows: First, the bottom layer of rigid viscoelastic material from step one is poured into the mold and left to stand at room temperature for 25 minutes to achieve a semi-cured state. Then, the middle layer of slightly softer viscoelastic material is poured on top of this and left to stand at room temperature for 25 minutes for semi-curing again. On top of this, the upper layer of soft viscoelastic material is poured and then left to stand at room temperature for 4 hours to allow the three layers of material to be completely cured so as to achieve the entanglement and curing of the molecular chain level into a uniform whole.

9. The gradient modulus adaptive damping material prepared by the preparation method according to any one of claims 1 to 8 is used for the protection of vibration of precision components.

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