Anti-puncture self-repairing composite material and preparation method thereof

Abstract

The invention provides an anti-puncture self-repairing composite material and a preparation method thereof, and belongs to the technical field of advanced functional composites.The anti-puncture self-repairing composite material comprises a gradient modulus three-layer structure, and the gradient modulus three-layer structure comprises an outer layer, a middle layer and an inner layer; wherein the outer layer is made of self-repairing thermoplastic polyurethane (TPU) containing dynamic bonds, and the modulus of the outer layer is 1-2 GPa; the middle layer is a titanium alloy woven mesh with micro grooves etched in the surface, and the modulus is 110 GPa; and the inner layer is an epoxy resin modified TPU bonding layer containing a silane coupling agent. Through gradient modulus design, multi-scale interface strengthening and a dynamic repair-energy dissipation synergistic mechanism, lightweight high protection (resistance to non-penetration of 50J impact), dual self-repair (airtightness recovery is greater than or equal to 95%) and long-acting stability (retention of damp-heat aging peel strength is greater than or equal to 90%) required by the fields of body armor and the like are realized; and meanwhile, the cost is reduced by 30% through process innovation, and the multi-scene adaptation capability of flexible electronic packaging and the like is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of advanced functional composite materials, and in particular to a puncture-resistant self-repairing composite material and a preparation method thereof. Background Art

[0002] Traditional puncture-proof materials (such as metal plates and UHMWPE) have problems such as heavy weight, poor flexibility, and irreversible damage. Existing self-healing materials (such as dynamic bond cross-linked TPU) can repair microcracks, but their puncture resistance is insufficient. The current technical difficulties are:

[0003] 1. Insufficient interface bonding strength: metal and polymer materials are prone to delamination due to differences in thermal expansion coefficients;

[0004] 2. The contradiction between self-repair and puncture resistance: self-repair requires material flexibility, while puncture resistance requires high rigidity;

[0005] 3. Process complexity: Microstructure design and large-scale production are difficult to be compatible.

[0006] The present invention solves the above problems through gradient modulus design, multi-scale interface strengthening technology and dynamic repair-energy dissipation synergistic mechanism.

[0007] To this end, a puncture-resistant self-repairable composite material and a preparation method thereof are proposed. Summary of the invention

[0008] The present invention aims to solve the problems raised in the background technology and provides a puncture-resistant self-repairing composite material and a preparation method thereof.

[0009] The specific technical solutions are as follows:

[0010] A puncture-resistant self-repairing composite material comprising:

[0011] A gradient modulus three-layer structure, the gradient modulus three-layer structure comprising an outer layer, a middle layer and an inner layer, wherein:

[0012] The outer layer is a self-healing thermoplastic polyurethane (TPU) containing dynamic bonds and has a modulus of 1-2 GPa;

[0013] The middle layer is a titanium alloy woven mesh with micro grooves etched on the surface, and the modulus is 110 GPa;

[0014] The inner layer is an epoxy resin modified TPU adhesive layer containing a silane coupling agent;

[0015] The wire diameter of the titanium alloy braided mesh is 0.08 mm, and the braiding density is 60×60 strands / cm 2 , the surface was plasma treated to generate hydroxyl (-OH) groups, and mechanical interlocking grooves with a width of 20 μm and a depth of 5 μm were formed by laser etching;

[0016] The outer layer, the middle layer, and the inner layer are combined through mechanical interlocking and covalent bonding of silicon-oxygen-titanium (Si-O-Ti), with a total thickness of 0.25 - 0.3 mm.

[0017] For the above puncture-resistant self-healing composite material, the dynamic bond in the self-healing TPU of the outer layer is selected from Diels-Alder (DA) bonds or ureidopyrimidinone (UPy) hydrogen bonds, and 0.1 - 0.5 wt% of zinc oxide (ZnO) nanoparticles are added as a photothermal catalyst.

[0018] For the above puncture-resistant self-healing composite material, the epoxy resin-modified TPU in the inner adhesive layer contains 1 - 2 wt% of silane coupling agent KH-550 and forms Si-O-Ti covalent bonds with the middle layer titanium mesh through a vacuum hot pressing process.

[0019] For the above puncture-resistant self-healing composite material, the titanium alloy woven mesh is replaced with a Z-shaped woven structure or an I-shaped 3D knitted structure filled with carbon fiber sheets. The warp and weft density of the Z-shaped weaving is 60×60 threads / cm 2 , and the cavity interval of the I-shaped 3D knitting is 1.5 - 4 cm.

[0020] The present invention also provides a method for preparing a puncture-resistant self-healing composite material, comprising the following steps:

[0021] a) Perform plasma treatment on titanium alloy wires with parameters of argon (Ar) atmosphere, power of 100 W, and time of 5 minutes. Subsequently, use a nanosecond pulsed laser (wavelength 1064 nm, energy density 2 J / cm 2 ) to etch surface grooves;

[0022] b) Double-sided coat the pretreated titanium mesh with molten self-healing TPU at 180 °C and cold press and shape it under a pressure of 10 MPa to below 40 °C;

[0023] c) Compose the inner adhesive layer and the middle layer through a vacuum hot pressing process with parameters of 80 °C, 5 MPa, and a holding pressure of 10 minutes.

[0024] For the above method for preparing a puncture-resistant self-healing composite material, the laser etching uses a multi-beam parallel system, the etching speed ≥ 0.5 m / min, and the distance between the titanium mesh conveyor belt and the laser head is 10 cm.

[0025] For the above method for preparing a puncture-resistant self-healing composite material, the surface roughness Ra of the titanium alloy woven mesh < 1 μm, and the plasma treatment depth ≤ 50 nm to avoid embrittlement of the titanium mesh.

[0026] The preparation method of the above-mentioned puncture-proof self-healing composite material, wherein 0.3 wt% of the hydrophobic agent KH-570 is added to the inner bonding layer, so that the peel strength retention rate is ≥90% after the material is aged at 85°C / 85% relative humidity (RH) for 500 hours.

[0027] The preparation method of the above-mentioned puncture-proof self-healing composite material, wherein the melt index (MFI) of the outer self-healing TPU is 15 g / 10 min, and the internal stress is controlled by a water-cooling process during the cold pressing and shaping process.

[0028] The preparation method of the above-mentioned puncture-proof self-healing composite material, wherein the puncture-proof self-healing composite material is not penetrated under a 50 J impact energy (NIJ0115.00 standard), and the airtightness recovery rate is ≥95% after 24 hours at room temperature or 2 hours of near-infrared light irradiation.

[0029] The present invention has the following beneficial effects:

[0030] Through gradient modulus design, multi-scale interface strengthening technology and dynamic repair-energy dissipation synergy mechanism, the present invention achieves the following technical effects:

[0031] 1. Performance synergistic optimization:

[0032] Puncture resistance: The viscoelastic dissipation of the outer TPU (loss factor tanδ = 0.3) and the plastic deformation of the titanium mesh (energy absorption 70%) act synergistically to resist a 50 J impact without penetration (NIJ0115.00 standard);

[0033] Self-healing ability: UPy hydrogen bonds are repaired at room temperature for 24 h or DA bonds are repaired by near-infrared light for 2 h, and the airtightness recovery rate is ≥95% (nitrogen leakage rate < 5×10 -6 mbar·L / s).

[0034] 2. Interface strengthening and stability:

[0035] Mechanical-chemical double bonding: Laser etching grooves (width 20 μm / depth 5 μm) form mechanical interlocks, combined with Si-O-Ti covalent bonds (KH-550 coupling), and the peel strength is ≥12 N / cm;

[0036] Environmental tolerance: After adding KH-570 hydrophobic agent, the peel strength retention rate is ≥90% after hydrothermal aging (85°C / 85% RH, 500 h).

[0037] 3. Process innovation and cost control:

[0038] Efficient etching: The multi-beam laser system (≥6 heads in parallel) increases the etching speed to ≥0.5 m / min, and the precision error < ±2 μm;

[0039] Lightweight design: The titanium mesh usage is reduced by 30% (compared to traditional metal layers), and the TPU is recyclable, effectively reducing raw material costs.

[0040] 4. Structural diversification adaptation:

[0041] Weaving variants: The Z-shaped weaving increases the shear strength by 25%, and the I-shaped 3D knitting filled with carbon fiber sheets enhances multi-directional impact resistance;

[0042] Function expansion: Photothermal catalytic ZnO nanoparticles (0.1 - 0.5 wt%) enable on-demand triggered repair, suitable for scenarios such as flexible electronic packaging.

[0043] This material can be widely used in fields such as bulletproof vests, protective clothing, aerospace flexible armor, and flexible electronic packaging, especially suitable for scenarios that require a balance of lightweight, high protection, and self-maintenance requirements. Description of the Drawings

[0044] Figure 1 It is a schematic structural diagram of the puncture-resistant and self-healing composite material provided by the embodiment of the present invention.

[0045] In the drawings:

[0046] 1. Outer layer; 2. Intermediate layer; 3. Inner layer. Detailed Embodiments

[0047] The technical solutions of the present invention will be further described below with reference to the drawings and through specific embodiments.

[0048] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation of this patent; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged, or reduced, which does not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0049] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0050] In the description of the present invention, unless otherwise clearly specified and defined, if terms such as "connection" are used to indicate the connection relationship between components, such terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The puncture-resistant and self-healing composite material provided by the present invention, as Figure 1 shown, includes: a gradient modulus three-layer structure, which includes an outer layer 1, an intermediate layer 2, and an inner layer 3, where:

[0052] The outer layer 1 is a self-healing thermoplastic polyurethane (TPU) containing dynamic bonds, with a modulus of 1 - 2 GPa;

[0053] The intermediate layer 2 is a titanium alloy woven mesh with surface-etched micro-grooves, with a modulus of 110 GPa;

[0054] The inner layer 3 is an epoxy resin-modified TPU adhesive layer containing a silane coupling agent;

[0055] The wire diameter of the titanium alloy woven mesh is 0.08 mm, and the weaving density is 60×60 strands / cm 2 , and the surface is treated by plasma to generate hydroxyl (-OH) groups, and mechanical interlocking grooves with a width of 20 μm and a depth of 5 μm are formed by laser etching;

[0056] The outer layer 1, the intermediate layer 2, and the inner layer 3 are combined through mechanical interlocking and Si-O-Ti covalent bonds, and the total thickness is 0.25 - 0.3 mm.

[0057] For the puncture-resistant and self-healing composite material provided by the above solution, through the gradient modulus design (outer layer 1 - 2 GPa, middle layer 110 GPa, inner layer 5 - 8 GPa), the impact energy is gradually transferred from the viscoelastic dissipation of the flexible outer layer → the plastic deformation of the rigid titanium mesh → the stable interface of the inner layer, synergistically improving the puncture resistance (not penetrated by 50 J) and the self-healing efficiency (airtightness recovery ≥ 95%). The plasma treatment and laser etching grooves (width 20 μm, depth 5 μm) on the surface of the titanium mesh form multi-scale mechanical interlocking, combined with Si-O-Ti covalent bonds, so that the interface peeling strength ≥ 12 N / cm, solving the delamination problem of traditional materials.

[0058] Among them, the dynamic bonds in the outer self-healing TPU are selected from Diels-Alder (DA) bonds or ureidopyrimidinone (UPy) hydrogen bonds, and 0.1-0.5 wt% of zinc oxide (ZnO) nanoparticles are added as a photothermal catalyst. The ZnO nanoparticles (0.1-0.5 wt%) as a photothermal catalyst have a photothermal conversion efficiency ≥40% under 808 nm near-infrared light irradiation, significantly accelerating the dynamic exchange of DA bonds, shortening the repair time from 24 h (at room temperature) to 2 h, and at the same time not affecting the flexibility of the TPU layer.

[0059] Among them, the epoxy resin-modified TPU in the inner bonding layer 3 contains 1-2 wt% of silane coupling agent KH-550, and forms Si-O-Ti covalent bonds with the intermediate layer titanium mesh through a vacuum hot pressing process. The 1-2 wt% KH-550 coupling agent in the epoxy resin-modified TPU forms Si-O-Ti covalent bonds with the -OH groups of the titanium mesh through vacuum hot pressing (80 °C / 5 MPa), combined with mechanical interlocking, increasing the interfacial bonding strength by 30%, and the retention rate of the peel strength after hygrothermal aging ≥90%, avoiding adhesive failure caused by hydrolysis.

[0060] Among them, the titanium alloy woven mesh is replaced with a Z-shaped woven structure or an I-shaped 3D knitted structure filled with carbon fiber sheets. The warp and weft density of the Z-shaped weaving is 60×60 per cm 2 , and the cavity interval of the I-shaped 3D knitting is 1.5-4 cm. The Z-shaped weaving (warp and weft angle 110°-120°) enhances the shear strength by 25% through fiber interlacing; the I-shaped 3D knitting cavity (interval 1.5-4 cm) is filled with carbon fiber sheets, improving the multi-directional impact resistance, and at the same time reducing the areal density of the material by 10%-15%.

[0061] The present invention also provides a preparation method of a puncture-proof self-healing composite material, including the following steps:

[0062] a) Perform plasma treatment on the titanium alloy wire, with parameters of argon (Ar) atmosphere, power 100 W, and time 5 minutes, and then use a nanosecond pulsed laser (wavelength 1064 nm, energy density 2 J / cm 2 ) to etch surface grooves;

[0063] b) Double-sided coat the pretreated titanium mesh with molten self-healing TPU at 180 °C, and cold press and shape it under a pressure of 10 MPa to below 40 °C;

[0064] c) Composite the inner bonding layer and the intermediate layer through a vacuum hot pressing process, with parameters of 80 °C, 5 MPa, and holding pressure for 10 minutes.

[0065] The preparation method of the puncture-resistant self-healing composite material uses plasma treatment (Ar / 100W / 5min) to generate -OH groups, combined with nanosecond laser etching (1064nm / 2J / cm 2 ), control the surface roughness Ra < 1μm, avoid embrittlement of the titanium mesh (treatment depth ≤ 50nm), ensure the uniformity of the groove morphology, and greatly improve the TPU filling rate.

[0066] Among them, the laser etching uses a multi-beam parallel system, the etching speed ≥ 0.5m / min, and the distance between the titanium mesh conveyor belt and the laser head is 10cm. The multi-beam parallel (≥6 heads) laser etching system increases the single etching speed from 0.2m / s to ≥ 0.5m / min, and the production efficiency is increased by 3 times, and the groove size error < ±2μm, meeting the requirements of large-scale production.

[0067] Among them, the surface roughness Ra of the titanium alloy woven mesh < 1μm, and the plasma treatment depth ≤ 50nm to avoid embrittlement of the titanium mesh. The surface roughness Ra of the titanium mesh < 1μm (Ra = 1.2μm after plasma treatment), optimize the melt fluidity of TPU, make the groove filling depth ≥ 5μm, and significantly improve the mechanical interlocking strength.

[0068] Among them, 0.3wt% of the hydrophobic agent KH-570 is added to the inner layer 3 adhesive layer, so that the peel strength retention rate of the material is ≥ 90% after aging at 85℃ / 85% relative humidity (RH) for 500 hours. 0.3wt% of the KH-570 hydrophobic agent is added to the inner layer, so that the contact angle of the material ≥ 110°, block the intrusion of water molecules into the interface, and the peel strength retention rate after hygrothermal aging (85℃ / 85%RH, 500h) is increased from 50% to ≥ 90%.

[0069] Among them, the melt index (MFI) of the outer layer 1 self-healing TPU is 15g / 10min, and the internal stress is controlled by water cooling during the cold pressing and shaping process. The U melt index MFI = 15g / 10min (melted at 180℃), combined with 10MPa cold pressing and shaping and water cooling process (cooled to 30℃), eliminate the internal stress, make the layer thickness error ≤ ±0.01mm, and avoid performance fluctuations caused by thermal degradation.

[0070] Among them, the puncture-resistant self-healing composite material is not penetrated under 50J impact energy (NIJ0115.00 standard), and the airtightness recovery rate is ≥ 95% after 24 hours at room temperature or 2 hours of near-infrared light irradiation. Through the viscoelastic dissipation of the outer layer TPU (loss factor tanδ = 0.3) and the plastic deformation of the titanium mesh (energy absorption 70%), it is not penetrated under 50J impact (NIJ0115.00 standard); after the UPy hydrogen bond is repaired at room temperature or the DA bond is repaired by photothermal, the nitrogen leakage rate < 5×10 -6 mbar·L / s, meeting the airtightness requirements of flexible electronic packaging.

[0071] The present invention also provides the following Examples 1-6:

[0072] Example 1 (laboratory level)

[0073] Steps and parameters:

[0074] 1. Pretreatment of titanium mesh:

[0075] Specification of titanium wire: TA2 pure titanium, wire diameter 0.08 mm;

[0076] Plasma treatment: argon atmosphere, power 100 W, time 5 minutes, generating hydroxyl (-OH) groups on the surface;

[0077] Laser etching: nanosecond pulsed laser (wavelength 1064 nm, energy density 2 J / cm 2 , scanning speed 0.2 m / s), groove size width 20 μm, depth 5 μm, roughness Ra = 1.2 μm.

[0078] 2. TPU coating:

[0079] Outer layer TPU: BASF Adding 1.5 wt% silane coupling agent KH-550 and 0.3 wt% ZnO nanoparticles;

[0080] Melting temperature: 180 °C (MFI = 15 g / 10 min), double-sided coating of titanium mesh.

[0081] 3. Composite process:

[0082] Cold pressing and shaping: pressure 10 MPa, water cooling to 30 °C, eliminating internal stress;

[0083] Vacuum hot pressing adhesive layer: Huntsman Modified TPU (containing 1.2 wt% KH-550), parameters 80 °C, 5 MPa, holding pressure for 10 minutes.

[0084] 4. Performance testing:

[0085] Peel strength: 13.5 N / cm (ASTM D903 standard);

[0086] Stab resistance performance: not penetrated under 55 J impact energy (NIJ 0115.00 standard);

[0087] Self-healing efficiency: after 2 hours of 808 nm near-infrared light irradiation, the airtightness recovery rate is 97% (nitrogen leakage rate < 4×10 - 6 mbar·L / s).

[0088] Example 2 (production line level)

[0089] Steps and Parameters:

[0090] 1. Titanium Mesh Pretreatment:

[0091] Using a multi-beam laser system (6 heads in parallel), the etching speed is increased to 0.6 m / min;

[0092] The plasma treatment parameters are the same as those in Example 1.

[0093] 2. Functional Modification:

[0094] Add 0.3 wt% KH-570 water repellent to the inner bonding layer to improve the stability in humid and hot environments.

[0095] 3. Composite Process:

[0096] The cold pressing and vacuum hot pressing parameters are the same as those in Example 1, but an automated feeding system is used, and the production rate is increased to 20 m / h.

[0097] 4. Performance Testing:

[0098] Humid and Hot Aging Test: After aging for 500 hours in an environment of 85°C / 85% RH, the retention rate of peel strength is 91%;

[0099] Consistency in Large-scale Production: For 10 batches of sample tests, the pass rate of puncture resistance (not penetrated at 50 J) is 100%.

[0100] Example 3 (Verification of Z-shaped Weaving Structure)

[0101] Steps and Parameters:

[0102] 1. Replacement of Titanium Mesh Structure:

[0103] Use a Z-shaped woven titanium mesh (warp and weft density 60×60 roots / cm 2 , weaving angle 115°);

[0104] Wire diameter 0.08 mm, and the surface treatment process is the same as that in Example 1.

[0105] 2. Composite Process:

[0106] The formulations of the outer TPU and the inner bonding layer are the same as those in Example 1.

[0107] 3. Performance Testing:

[0108] Shear Strength: It is increased by 27% compared with the plain weave structure (from 180 MPa to 229 MPa);

[0109] Multi-directional Impact Test: Under a 30 J oblique impact, the penetration depth is reduced by 40% (from 8 mm to 4.8 mm).

[0110] Example 4 (Optimization of Photo-thermal Repair Efficiency)

[0111] Steps and Parameters:

[0112] 1. TPU Modification:

[0113] The content of ZnO nanoparticles in the outer layer of TPU is increased to 0.5 wt%;

[0114] The depth of the laser-etched groove is adjusted to 8 μm (other parameters are the same as in Example 1).

[0115] 2. Repair Conditions:

[0116] Near-infrared light intensity: 1.5 W / cm 2 (wavelength 808 nm), repair time gradient test (0.5 h, 1 h, 2 h).

[0117] 3. Performance Test:

[0118] Repair efficiency: The airtightness recovery rate is 95% after 1 hour of light irradiation and 99% after 2 hours;

[0119] Thermal stability: There is no secondary cracking in the repaired area during the cyclic test from -20°C to 80°C.

[0120] Example 5 (Verification of Extreme Environment Tolerance)

[0121] Steps and Parameters:

[0122] 1. Environmental Test:

[0123] High temperature and high humidity: 70°C / 95% RH, lasting for 1000 hours;

[0124] Low temperature impact: After freezing at -40°C for 24 hours, immediately conduct a 50 J puncture resistance test.

[0125] 2. Performance Test:

[0126] Retention rate of peel strength: 88% after high temperature and high humidity, and no decrease in peel strength after low temperature impact;

[0127] Puncture resistance performance: Still meets the requirement of 50 J non-penetration under low temperature conditions (NIJ standard).

[0128] Example 6 (I-shaped 3D Knitted Structure)

[0129] Steps and Parameters:

[0130] 1. Titanium Mesh Structure Replacement:

[0131] Adopt an I-shaped 3D knitted titanium mesh with a cavity height of 2 mm and filled with carbon fiber sheets (spaced 2 cm); The surface treatment process is the same as in Example 1.

[0132] 2. Composite process:

[0133] The thickness of the inner bonding layer is increased to 0.06 mm to adapt to the cavity structure.

[0134] 3. Performance testing:

[0135] Areal density: Reduced by 12% (from 2.8 kg / m 2 to 2.46 kg / m 2 );

[0136] Multi-directional impact resistance: Under a 45 J impact, the energy absorption rate is increased by 18% (compared with the plain weave structure). Verified by the above embodiments:

[0137] Structural adaptability: Z-shaped and I-shaped weaves can respectively improve the shear strength and lightweight performance;

[0138] Repair controllability: The ZnO content and light intensity synergistically regulate the repair speed;

[0139] Environmental robustness: Stable performance in a wide temperature range from -40°C to 85°C and high humidity environment;

[0140] Scalability feasibility: The multi-beam laser system and automated production line ensure efficient and high-precision manufacturing. In summary, the puncture-resistant self-healing composite material and its preparation method provided by this embodiment have the following advantages:

[0141] Through gradient modulus design, multi-scale interface strengthening technology, and dynamic repair-energy dissipation synergistic mechanism, the present invention achieves the following technical effects:

[0142] 1. Synergistic optimization of performance:

[0143] Stab resistance: The viscoelastic dissipation of the outer layer TPU (loss factor tanδ = 0.3) and the plastic deformation of the titanium mesh (energy absorption 70%) act synergistically to resist a 50 J impact without penetration (NIJ0115.00 standard);

[0144] Self-healing ability: UPy hydrogen bonds can be repaired at room temperature for 24 h or DA bonds can be repaired by near-infrared light for 2 h, and the airtightness recovery rate ≥ 95% (nitrogen leakage rate < 5×10-6 mbar·L / s).

[0145] 2. Interface strengthening and stability:

[0146] Mechanical-chemical double bonding: Laser etching grooves (width 20 μm / depth 5 μm) form mechanical interlocks, combined with Si-O-Ti covalent bonds (KH-550 coupling), and the peel strength ≥ 12 N / cm;

[0147] Environmental tolerance: After adding KH-570 hydrophobic agent, the peel strength retention rate after wet heat aging (85℃ / 85%RH, 500h) is ≥90%.

[0148] 3. Process innovation and cost control:

[0149] Efficient etching: Multi-beam laser system (≥6 heads in parallel) increases the etching speed to ≥0.5m / min, with an accuracy error of <±2μm;

[0150] Lightweight design: The amount of titanium mesh is reduced by 30% (compared to traditional metal layers), and TPU can be recycled and reused, effectively reducing raw material costs.

[0151] 4. Structural diversification and adaptation:

[0152] Weaving variants: Z-shaped weaving increases shear strength by 25%, and I-shaped 3D knitting fills carbon fiber sheets to enhance multi-directional impact resistance;

[0153] Functional expansion: Photothermal catalytic ZnO nanoparticles (0.1-0.5wt%) can trigger repair on demand and adapt to scenarios such as flexible electronic packaging.

[0154] Technical Comparison Advantages

[0155] Index Traditional materials The present invention Stab resistance Metal plate (penetration depth of 50J > 15mm) 50J not penetrated (NIJ standard) Self-healing efficiency Microcrack repair requires > 48h Repaired at room temperature for 24h / photothermal for 2h Interface bonding strength ≤8N / cm (easy delamination) ≥12N / cm (mechanical-chemical bonding) Environmental stability Strength retention rate after hygrothermal aging < 50% ≥90% (modified with KH-570) Process cost High proportion of metal layer, non-recyclable Titanium mesh reduced by 30%, TPU recyclable

[0156] This material can be widely used in bulletproof vests, protective clothing, aerospace flexible armor, flexible electronic packaging and other fields, and is especially suitable for scenarios that require lightweight, high protection and self-maintenance.

[0157] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A puncture-resistant self-repairing composite material, characterized in that: include: A gradient modulus three-layer structure, the gradient modulus three-layer structure comprising an outer layer (1), a middle layer (2) and an inner layer (3), wherein: The outer layer (1) is a self-repairing thermoplastic polyurethane TPU containing dynamic bonds, and the modulus is 1-2 GPa; The intermediate layer (2) is a titanium alloy braided mesh with micro grooves etched on the surface, and the modulus is 110 GPa; The inner layer (3) is an epoxy resin modified TPU adhesive layer containing a silane coupling agent; The outer layer (1), the middle layer (2) and the inner layer (3) are covalently bonded with silicon-oxygen-titanium (Si-O-Ti) through mechanical interlocking, and the total thickness is 0.25-0.3 mm.

2. The puncture-resistant self-repairable composite material according to claim 1, characterized in that: The dynamic bonds in the outer layer (1) of the self-repairing TPU are selected from Diels-Alder bonds or ureido-pyrimidone hydrogen bonds, and 0.1-0.5wt% of zinc oxide nanoparticles are added as photothermal catalysts; the wire diameter of the titanium alloy braided mesh is 0.08mm, and the braiding density is 60×60 strands / cm 2 The surface was plasma treated to generate hydroxyl groups, and mechanical interlocking grooves with a width of 20 μm and a depth of 5 μm were formed by laser etching.

3. The puncture-resistant self-repairable composite material according to claim 1, characterized in that: The epoxy resin modified TPU in the inner layer (3) adhesive layer contains 1-2wt% of silane coupling agent KH-550, and forms Si-O-Ti covalent bonds with the middle layer titanium mesh through a vacuum hot pressing process.

4. The puncture-resistant self-repairable composite material according to claim 2, characterized in that: The titanium alloy braided mesh is replaced with a Z-shaped braided structure or an I-shaped 3D knitted structure filled with carbon fiber sheets, wherein the warp and weft density of the Z-shaped braid is 60×60 strands / cm 2 , the cavity interval of I-shaped 3D knitting is 1.5-4cm.

5. A method for preparing the puncture-resistant self-repairable composite material according to any one of claims 1 to 4, comprising the following steps: a) Plasma treatment of titanium alloy wire with parameters of argon atmosphere, power of 100 W, and time of 5 minutes, followed by surface groove etching with nanosecond pulse laser; b) coating the molten self-repairing TPU on both sides of the pretreated titanium mesh at 180° C., and cold pressing and shaping to below 40° C. at a pressure of 10 MPa; c) The inner adhesive layer and the middle layer are compounded by vacuum hot pressing process, with parameters of 80° C., 5 MPa, and holding pressure for 10 minutes.

6. The method for preparing the puncture-resistant self-repairable composite material according to claim 5, characterized in that: The laser etching adopts a multi-beam parallel system, the etching speed is ≥0.5m / min, and the distance between the titanium mesh conveyor belt and the laser head is 10cm.

7. The method for preparing the puncture-resistant self-repairable composite material according to claim 5, characterized in that: The surface roughness of the titanium alloy braided mesh Ra is less than 1 μm, and the plasma treatment depth is less than or equal to 50 nm to avoid embrittlement of the titanium mesh.

8. The method for preparing the puncture-resistant self-repairable composite material according to claim 5, characterized in that: 0.3 wt% of the hydrophobic agent KH-570 is added to the adhesive layer of the inner layer (3), so that the peel strength retention rate of the material after aging for 500 hours at 85°C / 85% relative humidity is ≥90%.

9. The method for preparing the puncture-resistant self-repairable composite material according to claim 5, characterized in that: The melt index of the self-repairing TPU of the outer layer (1) is 15 g / 10 min, and a water cooling process is used to control the internal stress during the cold pressing and shaping process.

10. The method for preparing the puncture-resistant self-repairable composite material according to claim 5, characterized in that: The puncture-resistant self-repairing composite material is not penetrated under an impact energy of 50 J, and has an airtightness recovery rate of ≥95% after 24 hours at room temperature or 2 hours of near-infrared light irradiation.

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