LCP fiber reinforced composite material

Abstract

The invention discloses an LCP fiber reinforced composite material, and particularly relates to the field of polymer composite materials. The material is composed of liquid crystal polymer resin powder, polybutylene terephthalate particles, an outer-layer continuous carbon fiber fabric, a middle-layer polyimide fiber tape, an inner-layer oriented glass fiber tape and an interface regulating agent. The preparation method comprises the following steps: respectively carrying out targeted interface pretreatment such as plasma etching, chemical grafting or electrostatic adsorption on the carbon fiber, the polyimide fiber and the glass fiber, laying from an outer layer to an inner layer, dispersing resin powder according to a specific proportion step by step, constructing a three-layer gradient structure, melting by adopting three-section gradient temperature rise, and carrying out heat preservation and heat preservation. And finally, compacting under the pressure of 3.0-4.0 MPa, and slowly cooling and demolding. According to the preparation method disclosed by the invention, through a multi-layer structure design and targeted interface modification, the problems of poor bonding between an LCP matrix and a fiber interface and remarkable anisotropy are effectively solved, and the comprehensive mechanical property of the material is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials, and particularly to an LCP fiber reinforced composite material. Background Technology

[0002] Liquid crystal polymers (LCPs) are a class of thermoplastic engineering plastics with a unique rigid molecular structure. Because they exhibit a highly ordered liquid crystal arrangement in the molten state, they possess excellent self-reinforcing properties, extremely high tensile strength, outstanding heat resistance, low moisture absorption, and low dielectric constant. With the surge in demand for 5G high-frequency communication, microelectronic packaging, and lightweight aerospace applications, LCP materials have become key materials for manufacturing high-frequency connectors, antenna modules, and high-performance structural components due to their advantages in precision molding and dimensional stability.

[0003] In existing technologies, fiber reinforcement modification techniques are commonly used to further overcome the performance bottlenecks of pure LCP resin. A common method involves melt-blending chopped glass fibers, carbon fibers, or aramid fibers with LCP resin using a twin-screw extruder. The high modulus of the fibers is used to improve the overall rigidity and heat distortion temperature of the composite material. Some existing technologies also attempt to add toughening agents to the LCP matrix or use fibers pretreated with silane coupling agents to improve processing performance.

[0004] Patent 202210393785.8 This invention uses PET as a matrix, loads graphene oxide on the surface of glass fiber, and then grows zinc oxide nanorods in situ to form a composite filler. Combined with chain extender and antioxidant, the composite material is prepared by blending and extrusion. This improves the fiber floating phenomenon of traditional glass fiber reinforced PET, while also giving the material antibacterial properties and improving mechanical properties.

[0005] Patent 202510386725.7 This invention uses KH-580 to graft mercapto groups onto the surface of glass fiber, and then combines it with a modifier made of quaternary ammonium salt and octene trichlorosilane through UV curing to obtain modified glass fiber. When combined with PET masterbatch and other additives, it solves the contradiction between the strength and impact resistance of traditional materials, improves the interfacial bonding force, and ensures good melt flowability, making it easy to form.

[0006] Patent 202410181037.2 This invention involves reacting polystyrene sulfonic acid with glass fiber and then loading boron nitride to form modified fibers. These modified fibers are then mixed with polyester resin and additives such as sodium silicate to prepare composite materials. This process improves the mechanical properties and thermal stability of the resin-based composite materials and enhances their applicability in specific environments.

[0007] Existing LCP fiber-reinforced composite materials still face many problems in practical applications. First, poor interfacial bonding performance is the core issue affecting its performance. LCP molecular chains are highly rigid, highly crystallinity, and have extremely low surface energy, exhibiting strong chemical inertness. This makes it difficult for LCP resin to fully wet the surface of carbon fibers or glass fibers. Traditional physical blending or simple surface treatments are insufficient to form strong interfacial chemical bonds, causing the composite material to easily debond and delaminate under stress, severely affecting the interlaminar shear strength and impact resistance of the material. LCP is also prone to orientation along the flow direction during flow, resulting in extremely high longitudinal strength but weak transverse strength, making the product prone to warping and deformation. Single short fiber reinforcement cannot solve this problem structurally.

[0008] While carbon fiber reinforcement offers good rigidity, it lacks toughness and is costly. Using only glass fiber results in high density and limited improvement in specific strength. Current technology lacks a composite material preparation scheme that can complement the advantages of different fibers through multi-level structural design and simultaneously solve the interfacial compatibility problem between LCP and multiple fibers.

[0009] Therefore, this invention proposes an LCP fiber-reinforced composite material that can solve the problems that LCP reinforcement often uses simple blending of single fibers, which easily leads to weak interfacial bonding, significant anisotropy, and limited performance. Summary of the Invention

[0010] The main objective of this invention is to provide an LCP fiber-reinforced composite material that can effectively solve the problems that LCP reinforcement often uses simple blending of single fibers, which easily leads to weak interfacial bonding, significant anisotropy, and limited performance.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An LCP fiber reinforced composite material, wherein the LCP fiber reinforced composite material comprises the following components by weight: 32-40 parts of liquid crystal polymer resin powder, 6-14 parts of polybutylene terephthalate microparticles, 16-22 parts of outer continuous carbon fiber fabric, 10-16 parts of middle continuous high-strength polyimide fiber tape, 16-24 parts of inner oriented glass fiber tape, and 0.8-1.8 parts of interface modifier.

[0012] Preferably, the particle size of the liquid crystal polymer resin powder is 80-120 μm, and the particle size of the polybutylene terephthalate microparticles is 20-40 μm.

[0013] Preferably, the outer continuous carbon fiber fabric is a plain or twill fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k; the middle continuous high-strength polyimide fiber tape has a single filament diameter of 12-16μm; and the inner oriented glass fiber tape has a single filament diameter of 18-22μm.

[0014] More preferably, the areal density of the twill fabric is 150–300 g / m². 2 The areal density of plain weave fabrics is 180–320 g / m³. 2 ; Preferably, the interface regulator is 1.5–2.5 g / m³. 2 Epoxy silane sol and 0.10–0.20 wt% amino aromatic hydrocarbon solution were used to treat the outer continuous carbon fiber fabric and the middle continuous high-strength polyimide fiber tape, respectively.

[0015] Preferably, the outer continuous carbon fiber fabric in the LCP fiber reinforced composite material is silane-treated. The silane treatment steps are as follows: drying 16-22 parts of the outer continuous carbon fiber fabric at 100-120°C for 1-2 hours, treating with 60-100W argon or oxygen ionizer for 60-120 seconds, and spraying an interface modifier at 1.5-2.5 g / m². 2 Then cure at 60-90℃ for 15-30 minutes.

[0016] Preferably, the middle layer continuous high-strength polyimide fiber tape in the LCP fiber reinforced composite material is surface-treated, and the surface treatment steps are as follows: take the middle layer continuous high-strength polyimide fiber tape of the formula and spray it with 0.10-0.20wt% amino aromatic hydrocarbon solution, and dry it at 110-130℃ for 15-25 minutes.

[0017] Preferably, the inner oriented glass fiber tape in the LCP fiber-reinforced composite material is electrostatically sprayed. The electrostatic spraying process involves heating the formulated amount of inner oriented glass fiber tape at 150–170°C for 6–10 minutes, followed by electrostatic spraying to achieve a density of 0.5–1.5 g / m². 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape.

[0018] A method for preparing LCP fiber-reinforced composite materials specifically includes the following steps: S1: Lay the outer carbon fiber fabric on the mold and disperse the liquid crystal polymer resin powder. Preheat at 250-270℃ for 20-40 seconds to form an anchoring layer between the resin powder and the carbon fiber. S2: A middle layer of polyimide fiber tape is laid on the anchoring layer, and liquid crystal polymer resin powder and polybutylene terephthalate powder are dispersed to form a middle layer structure. S3: An inner layer of oriented glass fiber tape is laid on the middle layer structure formed by S2, and polybutylene terephthalate powder is dispersed between the glass fibers to form a three-layer structure. S4: The completed three-layer structure is melt-impregnated in a closed mold; S5: After compaction at 3.0-4.0 MPa for 60-120 seconds, cool to 160-200℃ at 2-4℃ / min, and demold to obtain LCP fiber reinforced composite material.

[0019] Preferably, the mass ratio of the liquid crystal polymer resin powder used in step S1 to that used in step S2 is 6:4; and the weight ratio of the polybutylene terephthalate powder used in step S2 to that used in step S3 is 3:7.

[0020] Preferably, the melt impregnation step S4 involves maintaining the laid three-layer structure in a closed mold at 260–280°C for 1.5–3 minutes to densify the outer carbon fiber interface, maintaining it at 280–300°C for 2–4 minutes to allow the polyimide fiber to undergo chain segment diffusion with the liquid crystal polymer resin, and maintaining it at 300–320°C for 3–5 minutes to melt the polybutylene terephthalate and form an interfacial diffusion layer with the glass fiber, thus completing the degassing process.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention utilizes plasma, silane, and amino aromatic hydrocarbons to target and modify the surface properties of different fibers, forming a strong chemical bond and physical interaction interface. At the same time, PBT is used as a compatibilizing layer, effectively solving the core problem of poor wettability between LCP and various reinforcements, thereby significantly improving the interlaminar shear strength and impact resistance of the composite material.

[0022] 2. This invention uses a multi-layered heterogeneous structure design of "carbon fiber-polyimide fiber-glass fiber" to organically combine the advantages of different fibers, thereby achieving the ability to transfer stress and absorb energy layer by layer. The outer layer ensures the stiffness and dimensional stability of the material, the middle layer improves toughness and fatigue resistance, and the inner layer improves strength and cost. The resulting composite material achieves strong bonding between LCP and fiber interface and low porosity. Attached Figure Description

[0023] Figure 1 A schematic diagram of the process for preparing an LCP fiber-reinforced composite material; Figure 2 SEM image of the outer continuous carbon fiber fabric after silane treatment; Figure 3 SEM image of the surface-treated, continuous high-strength polyimide fiber tape in the middle layer; Figure 4 SEM image of the oriented glass fiber tape after electrostatic spraying; Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0025] like Figure 1 The diagram shows a process flow chart for preparing an LCP fiber-reinforced composite material. The specific materials and implementation steps are as follows: S1: Weigh 16–22 portions of the outer continuous carbon fiber fabric and dry it at 100–120°C for 1–2 hours to remove adsorbed moisture. Place the dried outer continuous carbon fiber fabric in a plasma treatment device and treat it with 60–100W argon or oxygen plasma for 60–120 seconds to form a micro-etched layer of 0.3–1.0 nm. Spray 1.5–2.5 g / m 2 The epoxy silane sol is cured at 60-90℃ for 15-30 minutes and then laid in the mold. After the silane is cured, the outer continuous carbon fiber fabric is laid in the mold, and liquid crystal polymer resin powder is evenly laid on its surface. It is preheated at 250-270℃ for 20-40 seconds to soften the resin powder and penetrate it to form an anchoring layer with the carbon fiber.

[0026] S2: The middle layer continuous high-strength polyimide fiber tape is surface treated. 10-16 parts of the middle layer continuous high-strength polyimide fiber tape are sprayed with 0.10-0.20 wt% amino aromatic hydrocarbon solution and dried at 110-130℃ for 15-25 minutes to form an interface control layer with π-π interaction capability on the fiber surface. The surface-treated middle layer continuous high-strength polyimide fiber tape is laid on the anchoring layer of step S1 and sprayed on the anchoring layer of S1. The mass ratio of liquid crystal polymer resin powder used in step S1 to step S2 is 6:4, so that the above mixed powder fills the gaps in the polyimide fiber tape to construct the middle layer powder structure.

[0027] S3: Take 16-24 portions of inner-layer oriented glass fiber tape and heat at 150-170℃ for 6-10 minutes to activate the hydroxyl groups on the fiber surface. Then, apply the fiber by electrostatic spraying to achieve a fiber density of 0.5-1.5 g / m². 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape to form a pre-wetting layer that can generate interfacial diffusion in the subsequent melting stage. The treated inner layer oriented glass fiber tape is laid on the intermediate layer powder structure in step S2, wherein the weight ratio of the polybutylene terephthalate powder used in step S2 to step S3 is 3:7.

[0028] S4: Hold the three-layer structure constructed in steps S1 to S3 in a closed mold and perform gradient heating in the temperature zones sequentially: First temperature zone: 260~280℃ for 1.5~3 minutes to allow the molten LCP in the outer carbon fiber interface to be fully impregnated and densified; Second temperature zone: 280~300℃ for 2~4 minutes to allow polyimide fibers and liquid crystal polymer resin to undergo segment diffusion and form a middle diffusion interface; The third temperature zone: maintain 300-320℃ for 3-5 minutes to allow the polybutylene terephthalate powder to melt and form a continuous interfacial diffusion layer with the glass fiber, while simultaneously completing the internal gas discharge.

[0029] The above heating process uses a stepped temperature control method and keeps the mold closed to improve resin impregnation efficiency.

[0030] S5: After the temperature zone treatment is completed, apply a pressure of 3.0 to 4.0 MPa to the closed mold and hold for 60 to 120 seconds to achieve a tight bond between the three layers and discharge of residual gas.

[0031] Subsequently, the mold temperature was reduced to 160–200°C at a cooling rate of 2–4°C / min. At this temperature, the pressure was released and the mold was demolded, yielding a liquid crystal polymer fiber-reinforced composite material with a clear structural hierarchy, continuous interfaces, and low porosity. All examples used epoxy silane sol (batch number KH-560) and amino aromatic hydrocarbon solution (batch number A112123).

[0032] The scheme uses liquid crystal polymer resin powder with a particle size of 80-120μm, polybutylene terephthalate microparticles with a particle size of 20-40μm, outer continuous carbon fiber fabric with a warp and weft density of 3k×3k, middle continuous high-strength polyimide fiber tape with a single filament diameter of 12-16μm, and inner oriented glass fiber tape with a single filament diameter of 18-22μm.

[0033] Figure 1 The image shows a SEM image of the outer continuous carbon fiber fabric after silane treatment, revealing a clear warp and weft interlacing and a distinct weaving structure.

[0034] Figure 3 This is a SEM image of the surface-treated, continuous high-strength polyimide fiber tape in the middle layer. The fiber tapes are arranged in parallel, and some surface-treated particles are visible on the surface.

[0035] Figure 4 The image shows an SEM image of the oriented glass fiber tape after electrostatic spraying. It can be seen that the fibers are straighter and more regularly oriented, and the smooth interface indicates that a continuous diffusion layer has been formed at the glass fiber interface.

[0036] Example 1 A method for preparing an LCP fiber-reinforced composite material includes the following steps: S1: Weigh 16 portions of 80μm outer layer continuous carbon fiber fabric and dry at 100℃ for 1 hour to remove adsorbed moisture. Place the dried outer layer continuous carbon fiber fabric in a plasma treatment device and treat with 60W argon or oxygen plasma for 60 seconds to form a 0.3nm micro-etched layer; spray 1.5g / m 2 The epoxy silane sol was cured at 60°C for 150 minutes and then laid in the mold. After the silane was cured, the outer continuous carbon fiber fabric was laid in the mold, and liquid crystal polymer resin powder was evenly laid on its surface. It was preheated at 250°C for 20 seconds.

[0037] S2: Surface-treat the middle layer continuous high-strength polyimide fiber tape, weigh 10 parts of the middle layer continuous high-strength polyimide fiber tape and spray it with 0.10wt% amino aromatic hydrocarbon solution, dry it at 110℃ for 15 minutes, and spray the surface-treated middle layer continuous high-strength polyimide fiber tape onto the anchoring layer in step S1, wherein the mass ratio of the liquid crystal polymer resin powder used in step S1 to step S2 is 6:4.

[0038] S3: Take 16 portions of inner-layer oriented glass fiber tape, heat at 150℃ for 6 minutes, and then electrostatically spray to achieve a density of 0.5 g / m. 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape, and the treated inner layer oriented glass fiber tape is laid on the middle layer powder structure in step S2, wherein the weight ratio of the polybutylene terephthalate powder used in step S2 to step S3 is 3:7.

[0039] S4: Hold the three-layer structure constructed in steps S1 to S3 in a closed mold and perform gradient heating in the temperature zones sequentially: First temperature zone: 260℃ for 1.5 minutes to allow the molten LCP in the outer carbon fiber interface to be fully impregnated and densified; Second temperature zone: Maintain at 280℃ for 2 minutes to allow polyimide fibers and liquid crystal polymer resin to undergo segment diffusion and form a middle diffusion interface; The third temperature zone: maintain 300℃ for 3 minutes to melt the polybutylene terephthalate powder and form a continuous interfacial diffusion layer with the glass fiber, while simultaneously completing the internal gas discharge.

[0040] The above heating process uses a stepped temperature control method.

[0041] S5: After the temperature zone treatment is completed, apply a pressure of 3.0 MPa to the closed mold and hold for 60 seconds to achieve a tight bond between the three layers and the discharge of residual gas.

[0042] Subsequently, the mold temperature was reduced to 160°C at a cooling rate of 2°C / min. At this temperature, the pressure was released and the mold was demolded, resulting in a liquid crystal polymer fiber reinforced composite material with a clear structural hierarchy, continuous interface, and low porosity.

[0043] The above scheme uses 20μm polybutylene terephthalate microparticles; the outer continuous carbon fiber fabric is a plain weave fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k, and the areal density of the plain weave fabric is 180g / m². 2 The middle layer of continuous high-strength polyimide fiber tape has a single filament diameter of 12μm, and the inner layer of oriented glass fiber tape has a single filament diameter of 18μm.

[0044] Example 2 A method for preparing an LCP fiber-reinforced composite material includes the following steps: S1: Weigh 22 portions of 120μm outer layer continuous carbon fiber fabric and dry at 120℃ for 2 hours to remove adsorbed moisture. Place the dried outer layer continuous carbon fiber fabric in a plasma treatment device and treat with 100W argon or oxygen plasma for 120 seconds to form a 1.0nm micro-etched layer; spray 2.5g / m 2 The epoxy silane sol was cured at 90°C for 30 minutes and then laid in the mold. After the silane was cured, the outer continuous carbon fiber fabric was laid in the mold, and liquid crystal polymer resin powder was evenly laid on its surface. It was preheated at 270°C for 40 seconds.

[0045] S2: Surface-treat the middle layer continuous high-strength polyimide fiber tape, weigh 16 parts of the middle layer continuous high-strength polyimide fiber tape and spray it with 0.20wt% amino aromatic hydrocarbon solution, dry it at 130℃ for 25 minutes, and spray the surface-treated middle layer continuous high-strength polyimide fiber tape onto the anchoring layer in step S1, wherein the mass ratio of the liquid crystal polymer resin powder used in step S1 to step S2 is 6:4.

[0046] S3: Take 16-24 portions of inner-layer oriented glass fiber tape, heat at 170℃ for 10 minutes, and then electrostatically spray to achieve a density of 1.5 g / m². 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape, and the treated inner layer oriented glass fiber tape is laid on the middle layer powder structure in step S2, wherein the weight ratio of the polybutylene terephthalate powder used in step S2 to step S3 is 3:7.

[0047] S4: Hold the three-layer structure constructed in steps S1 to S3 in a closed mold and perform gradient heating in the temperature zones sequentially: First temperature zone: 280℃ for 3 minutes to fully wet and densify the molten LCP in the outer carbon fiber interface; Second temperature zone: Maintain at 300℃ for 4 minutes to allow polyimide fibers and liquid crystal polymer resin to undergo segment diffusion and form a middle diffusion interface; The third temperature zone: maintain 320℃ for 5 minutes to melt the polybutylene terephthalate powder and form a continuous interfacial diffusion layer with the glass fiber, while simultaneously completing the internal gas discharge.

[0048] The above heating process uses a stepped temperature control method.

[0049] S5: After the temperature zone treatment is completed, apply a pressure of 4.0 MPa to the closed mold and hold for 120 seconds to achieve a tight bond between the three layers and the discharge of residual gas.

[0050] Subsequently, the mold temperature was reduced to 200°C at a cooling rate of 4°C / min. At this temperature, the pressure was released and the mold was demolded, resulting in a liquid crystal polymer fiber reinforced composite material with a clear structural hierarchy, continuous interface, and low porosity.

[0051] The above scheme uses 40μm polybutylene terephthalate microparticles; the outer continuous carbon fiber fabric is a plain weave fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k, and the areal density of the plain weave fabric is 180~320g / m². 2 The middle layer of continuous high-strength polyimide fiber tape has a single filament diameter of 16μm, and the inner layer of oriented glass fiber tape has a single filament diameter of 22μm.

[0052] Example 3 A method for preparing an LCP fiber-reinforced composite material includes the following steps: S1: Weigh 19 portions of 100μm outer layer continuous carbon fiber fabric and dry it at 110℃ for 1.5 hours to remove adsorbed moisture. Place the dried outer layer continuous carbon fiber fabric in a plasma treatment device and treat it with 80W argon or oxygen plasma for 80 seconds to form a 0.6nm micro-etched layer; spray 2.0g / m 2 The epoxy silane sol was cured at 75°C for 22 minutes and then laid in the mold. After the silane was cured, the outer continuous carbon fiber fabric was laid in the mold, and liquid crystal polymer resin powder was evenly laid on its surface. It was preheated at 260°C for 30 seconds.

[0053] S2: Surface-treat the middle layer continuous high-strength polyimide fiber tape, weigh 13 parts of the middle layer continuous high-strength polyimide fiber tape and spray it with 0.15wt% amino aromatic hydrocarbon solution, dry it at 120℃ for 20 minutes, and spray the surface-treated middle layer continuous high-strength polyimide fiber tape onto the anchoring layer in step S1, wherein the mass ratio of the liquid crystal polymer resin powder used in step S1 to step S2 is 6:4.

[0054] S3: Take 20 portions of inner-layer oriented glass fiber tape and heat at 160℃ for 8 minutes, then electrostatically spray to achieve a density of 1.0 g / m². 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape, and the treated inner layer oriented glass fiber tape is laid on the middle layer powder structure in step S2, wherein the weight ratio of the polybutylene terephthalate powder used in step S2 to step S3 is 3:7.

[0055] S4: Hold the three-layer structure constructed in steps S1 to S3 in a closed mold and perform gradient heating in the temperature zones sequentially: First temperature zone: 270℃ for 2.2 minutes to allow the molten LCP in the outer carbon fiber interface to be fully impregnated and densified; Second temperature zone: Maintain at 290℃ for 3 minutes to allow polyimide fibers and liquid crystal polymer resin to undergo segment diffusion and form a middle diffusion interface; The third temperature zone: 310℃ for 4 minutes, to melt the polybutylene terephthalate powder and form a continuous interfacial diffusion layer with the glass fiber, while simultaneously completing the internal gas discharge.

[0056] The above heating process uses a stepped temperature control method.

[0057] S5: After the temperature zone treatment is completed, apply a pressure of 3.5MPa to the closed mold and hold for 90 seconds to achieve a tight bond between the three layers and the discharge of residual gas.

[0058] Subsequently, the mold temperature was reduced to 180°C at a cooling rate of 3°C / min. At this temperature, the pressure was released and the mold was demolded, resulting in a liquid crystal polymer fiber reinforced composite material with a clear structural hierarchy, continuous interface, and low porosity.

[0059] The above scheme uses 30μm polybutylene terephthalate microparticles; the outer continuous carbon fiber fabric is a twill fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k, and the areal density of the twill fabric is 150-300g / m². 2 The middle layer of continuous high-strength polyimide fiber tape has a single filament diameter of 14μm, and the inner layer of oriented glass fiber tape has a single filament diameter of 20μm.

[0060] Example 4 A method for preparing an LCP fiber-reinforced composite material includes the following steps: S1: Weigh 17 portions of 82μm outer layer continuous carbon fiber fabric and dry at 105℃ for 1 hour to remove adsorbed moisture. Place the dried outer layer continuous carbon fiber fabric in a plasma treatment device and treat with 65W argon or oxygen plasma for 65 seconds to form a 0.4nm micro-etched layer; spray 1.6g / m2 The epoxy silane sol was cured at 65°C for 16 minutes and then laid in the mold. After the silane was cured, the outer continuous carbon fiber fabric was laid in the mold, and liquid crystal polymer resin powder was evenly laid on its surface. It was preheated at 255°C for 25 seconds.

[0061] S2: Surface-treat the middle layer continuous high-strength polyimide fiber tape. Weigh 11 parts of the middle layer continuous high-strength polyimide fiber tape and spray it with 0.11wt% amino aromatic hydrocarbon solution. Dry it at 112℃ for 16 minutes. Spray the surface-treated middle layer continuous high-strength polyimide fiber tape onto the anchoring layer in step S1. The mass ratio of the liquid crystal polymer resin powder used in step S1 to step S2 is 6:4.

[0062] S3: Take 17 portions of inner-layer oriented glass fiber tape, heat at 155℃ for 7 minutes, and then electrostatically spray to achieve a density of 0.6 g / m. 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape, and the treated inner layer oriented glass fiber tape is laid on the middle layer powder structure in step S2, wherein the weight ratio of the polybutylene terephthalate powder used in step S2 to step S3 is 3:7.

[0063] S4: Hold the three-layer structure constructed in steps S1 to S3 in a closed mold and perform gradient heating in the temperature zones sequentially: First temperature zone: 265℃ for 1.5 to 3 minutes to allow the molten LCP in the outer carbon fiber interface to be fully impregnated and densified; Second temperature zone: Maintain at 285℃ for 2 to 4 minutes to allow polyimide fibers and liquid crystal polymer resin to undergo segment diffusion and form a middle diffusion interface; The third temperature zone: maintain 305℃ for 3 to 5 minutes to melt the polybutylene terephthalate powder and form a continuous interfacial diffusion layer with the glass fiber, while simultaneously completing the internal gas discharge.

[0064] The above heating process uses a stepped temperature control method.

[0065] S5: After the temperature zone treatment is completed, apply a pressure of 3.1 MPa to the closed mold and hold for 65 seconds to achieve a tight bond between the three layers and the discharge of residual gas.

[0066] Subsequently, the mold temperature was reduced to 165°C at a cooling rate of 2°C / min. At this temperature, the pressure was released and the mold was demolded, resulting in a liquid crystal polymer fiber reinforced composite material with a clear structural hierarchy, continuous interface, and low porosity.

[0067] The above scheme uses 25μm polybutylene terephthalate microparticles; the outer continuous carbon fiber fabric is a twill fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k, and the areal density of the twill fabric is 150-300g / m². 2 The middle layer of continuous high-strength polyimide fiber tape has a single filament diameter of 13μm, and the inner layer of oriented glass fiber tape has a single filament diameter of 19μm.

[0068] Example 5 A method for preparing an LCP fiber-reinforced composite material includes the following steps: S1: Weigh 21 portions of 118μm outer layer continuous carbon fiber fabric and dry at 118℃ for 2 hours to remove adsorbed moisture. Place the dried outer layer continuous carbon fiber fabric in a plasma treatment device and treat with 95W argon or oxygen plasma for 115 seconds to form a 0.9nm micro-etched layer; spray 2.1g / m 2 The epoxy silane sol was cured at 85°C for 25 minutes and then laid in the mold. After the silane was cured, the outer continuous carbon fiber fabric was laid in the mold, and liquid crystal polymer resin powder was evenly laid on its surface. It was preheated at 268°C for 38 seconds.

[0069] S2: Surface-treat the middle layer continuous high-strength polyimide fiber tape, weigh 15 parts of the middle layer continuous high-strength polyimide fiber tape and spray it with 0.19wt% amino aromatic hydrocarbon solution, dry it at 128℃ for 22 minutes, and spray the surface-treated middle layer continuous high-strength polyimide fiber tape onto the anchoring layer in step S1, wherein the mass ratio of the liquid crystal polymer resin powder used in step S1 to step S2 is 6:4.

[0070] S3: Take 23 portions of inner-layer oriented glass fiber tape and heat at 168℃ for 9 minutes, then electrostatically spray to achieve a density of 1.4 g / m². 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape, and the treated inner layer oriented glass fiber tape is laid on the middle layer powder structure in step S2, wherein the weight ratio of the polybutylene terephthalate powder used in step S2 to step S3 is 3:7.

[0071] S4: Hold the three-layer structure constructed in steps S1 to S3 in a closed mold and perform gradient heating in the temperature zones sequentially: First temperature zone: 278℃ for 3 minutes to fully wet and densify the molten LCP in the outer carbon fiber interface; Second temperature zone: Maintain at 295℃ for 4 minutes to allow polyimide fibers and liquid crystal polymer resin to undergo segment diffusion and form a middle diffusion interface; The third temperature zone: maintain 318℃ for 5 minutes to melt the polybutylene terephthalate powder and form a continuous interfacial diffusion layer with the glass fiber, while simultaneously completing the internal gas discharge.

[0072] The above heating process uses a stepped temperature control method.

[0073] S5: After the temperature zone treatment is completed, apply a pressure of 3.8 MPa to the closed mold and hold for 115 seconds to achieve a tight bond between the three layers and the discharge of residual gas.

[0074] Subsequently, the mold temperature was reduced to 195°C at a cooling rate of 4°C / min. At this temperature, the pressure was released and the mold was demolded, resulting in a liquid crystal polymer fiber reinforced composite material with a clear structural hierarchy, continuous interface, and low porosity.

[0075] The above scheme uses 35μm polybutylene terephthalate microparticles; the outer continuous carbon fiber fabric is a twill fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k, and the areal density of the twill fabric is 150-300g / m². 2 The middle layer of continuous high-strength polyimide fiber tape has a single filament diameter of 15μm, and the inner layer of oriented glass fiber tape has a single filament diameter of 20μm.

[0076] Comparative Example 1 The outer continuous carbon fiber fabric, the middle continuous high-strength polyimide fiber tape, and the inner oriented glass fiber tape are not silanized, surface-treated, or electrostatically adsorbed. The remaining steps are the same as in Example 1.

[0077] Comparative Example 2 Only a single-layer glass fiber structure is used, the resin powder laying method remains the same, and the remaining steps are the same as in Example 1.

[0078] Comparative Example 3 The three-layer pre-laid structure was directly melted at a single-section constant temperature of 300°C, and the remaining steps were the same as in Example 1.

[0079] The LCP fiber reinforced composite materials prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following performance tests: 1. Tensile properties Referring to GB / T1040.1–2018, the test method for tensile properties of plastics, the specimen is clamped in the upper and lower fixtures of the tensile testing machine and adjusted so that its axis is consistent with the tensile direction; the tensile rate is set to 5 mm / min and the load-displacement or stress-strain curve is recorded; the test continues until the specimen breaks and the maximum load is read.

[0080] 2. Bending performance Referring to GB / T9341–2008 Test Method for Bending Properties of Plastics, place the specimen flat on two support rollers with the loading roller located at the midpoint of the span. Set a bending loading rate of 2 mm / min and apply the load until the specimen breaks or reaches the specified deflection. Record the maximum load and the corresponding deflection.

[0081] 3. Impact performance Referring to GB / T1043.1–2008 Cantilever Beam Impact, clamp the specimen with the notch facing the pendulum on the specimen holder; raise the pendulum to the specified height, release the pendulum to impact the specimen; record the energy absorbed when the specimen breaks.

[0082] 4. Interlaminar shear strength Referring to GB / T3354–2014 Fiber Reinforced Plastics Interlaminar Shear Strength Test Method (short beam method), place the specimen on the support roller, with the loading roller located at the midpoint of the span, and load at a rate of 1 mm / min until the specimen fails in shear; record the maximum load.

[0083] 5. Porosity testing Referring to GB / T3365–2008, the method for determining porosity, the mass m of the sample is weighed using an analytical balance, and the volume V of the sample is determined using the liquid displacement method or the density gradient method. The actual density is then calculated: ρ 实 =m a / V, based on the density and mass fraction of each component in the formula, such as LCP, PBT, carbon fiber, PI fiber, and glass fiber, the theoretical density ρ is calculated according to the mixing rule. 理 ; Calculate the volumetric porosity using the standard formula: P(%) = (1 - ρ) 实 / ρ 理 )×100% 6. Water absorption Referring to GB / T1034–2008, the method for determining the water absorption rate of plastics, the sample is completely immersed in deionized water or distilled water at a temperature of 23±2℃. The specified soaking time is 24h. After soaking, the sample is removed, the surface moisture is quickly wiped off with filter paper, and the wet mass m is immediately measured.

[0084] The performance test results of the LCP fiber reinforced composite materials prepared in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1: Table 1: Performance test results of samples prepared in the examples and comparative examples:

[0085] In terms of mechanical properties, the tensile strength of Examples 1-5 reached 500-520 MPa, an increase of approximately 11-21% compared to the untreated comparative example; the flexural strength reached 730-750 MPa, an increase of approximately 7-10%; and the notched impact strength of the cantilever beam was particularly outstanding at 77-85 kJ·m. -2 The load-bearing capacity, impact resistance, and interlaminar bond strength are increased by approximately 28-42%, and the interlaminar shear strength reaches 70-72 MPa, an increase of approximately 40-44%. These data clearly demonstrate that the present invention significantly improves the material's load-bearing capacity, impact resistance, and interlaminar bond strength by enhancing interfacial bonding and the energy dissipation mechanism layer by layer.

[0086] The physical performance test results further verified the effectiveness of the process of the present invention. The porosity of the embodiment was only 0.60-0.80%, which was reduced by about 47-60% compared with the comparative example; the 24-hour water absorption rate was also reduced to 0.07-0.08%, a reduction of 33-42%. This is attributed to the optimization of the three-stage stepped melting process and the subsequent compaction process, the full wetting of the fibers by the resin and the expulsion of internal gas, thereby improving the density and environmental resistance of the material.

[0087] This invention achieves a systematic breakthrough in the mechanical strength, interfacial bonding, impact resistance, and structural density of LCP fiber-reinforced composite materials through structural innovation of the material system and precise control of the manufacturing process. This composite material possesses excellent comprehensive properties of high stiffness, high toughness, low porosity, and low water absorption, making it suitable for high-end engineering fields with stringent requirements for lightweighting, high reliability, and weather resistance.

[0088] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An LCP fiber-reinforced composite material, characterized in that, The LCP fiber reinforced composite material comprises the following components by weight: 32-40 parts of liquid crystal polymer resin powder, 6-14 parts of polybutylene terephthalate microparticles, 16-22 parts of outer continuous carbon fiber fabric, 10-16 parts of middle continuous high-strength polyimide fiber tape, 16-24 parts of inner oriented glass fiber tape, and 0.8-1.8 parts of interface modifier.

2. The LCP fiber-reinforced composite material according to claim 1, characterized in that, The liquid crystal polymer resin powder has a particle size of 80–120 μm, and the polybutylene terephthalate microparticles have a particle size of 20–40 μm.

3. The LCP fiber-reinforced composite material according to claim 1, characterized in that, The outer continuous carbon fiber fabric is a plain or twill fabric woven from continuous carbon fiber bundles, with a warp and weft density of 3k×3k; the middle continuous high-strength polyimide fiber tape has a single filament diameter of 12-16μm; and the inner oriented glass fiber tape has a single filament diameter of 18-22μm.

4. The LCP fiber-reinforced composite material according to claim 1, characterized in that, The interface modifier is 1.5–2.5 g / m³. 2 Epoxy silane sol and 0.10–0.20 wt% amino aromatic hydrocarbon solution were used to treat the outer continuous carbon fiber fabric and the middle continuous high-strength polyimide fiber tape, respectively.

5. The LCP fiber-reinforced composite material according to claim 1, characterized in that, The outer continuous carbon fiber fabric in the LCP fiber reinforced composite material is silane-treated. The silane treatment steps are as follows: 16-22 parts of the outer continuous carbon fiber fabric are dried at 100-120°C for 1-2 hours, treated with 60-100W argon or oxygen ionizer for 60-120 seconds, and an interface modifier is sprayed at 1.5-2.5 g / m². 2 Then cure at 60-90℃ for 15-30 minutes.

6. The LCP fiber-reinforced composite material according to claim 1, characterized in that, The middle layer of continuous high-strength polyimide fiber tape in the LCP fiber reinforced composite material is surface-treated. The surface treatment steps are as follows: take the middle layer of continuous high-strength polyimide fiber tape of the formula and spray it with 0.10-0.20 wt% amino aromatic hydrocarbon solution, and dry it at 110-130℃ for 15-25 minutes.

7. The LCP fiber-reinforced composite material according to claim 1, characterized in that, The inner oriented glass fiber tape in the LCP fiber-reinforced composite material is electrostatically sprayed. The electrostatic spraying process involves heating the formulated amount of inner oriented glass fiber tape at 150–170°C for 6–10 minutes, followed by electrostatic spraying to achieve a density of 0.5–1.5 g / m². 2 The polybutylene terephthalate powder is uniformly adsorbed onto the surface of the glass fiber tape.

8. A method for preparing the LCP fiber-reinforced composite material according to any one of claims 1 to 7, characterized in that, Specifically, the following steps are included: S1: Lay the outer carbon fiber fabric on the mold and disperse the liquid crystal polymer resin powder. Preheat at 250-270℃ for 20-40 seconds to form an anchoring layer between the resin powder and the carbon fiber. S2: A middle layer of polyimide fiber tape is laid on the anchoring layer, and liquid crystal polymer resin powder and polybutylene terephthalate powder are dispersed to form a middle layer structure. S3: An inner layer of oriented glass fiber tape is laid on the middle layer structure formed by S2, and polybutylene terephthalate powder is dispersed between the glass fibers to form a three-layer structure. S4: The completed three-layer structure is melt-impregnated in a closed mold; S5: After compaction at 3.0-4.0 MPa for 60-120 seconds, cool to 160-200℃ at 2-4℃ / min, and demold to obtain LCP fiber reinforced composite material.

9. The method for preparing LCP fiber-reinforced composite materials according to claim 8, characterized in that, The mass ratio of the liquid crystal polymer resin powder used in step S1 to that used in step S2 is 6:4; the weight ratio of the polybutylene terephthalate powder used in step S2 to that used in step S3 is 3:

7.

10. The method for preparing LCP fiber-reinforced composite materials according to claim 8, characterized in that, The melt impregnation step S4 involves holding the laid three-layer structure in a closed mold at 260–280°C for 1.5–3 minutes to densify the interface of the outer carbon fiber layer, holding it at 280–300°C for 2–4 minutes to allow the polyimide fiber to undergo chain segment diffusion with the liquid crystal polymer resin, and holding it at 300–320°C for 3–5 minutes to melt the polybutylene terephthalate and form an interface diffusion layer with the glass fiber, thus completing the degassing process.

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