A woven oxford fabric-polypropylene screw extrusion hot melt composite material, preparation method and application thereof

Abstract

This invention relates to the field of protective composite materials technology, specifically to a screw-extruded hot-melt composite material of woven Oxford cloth and polypropylene, its preparation method, and its application. The composite material is formed by screw extrusion hot-melt bonding of a polypropylene film layer and a woven Oxford cloth fabric layer. At the interface between the polypropylene film layer and the woven Oxford cloth fabric layer, the polypropylene film layer penetrates into the fiber gaps of the woven Oxford cloth fabric layer, forming a penetration and embedding zone, and / or the polypropylene film layer forms a coating structure on the fiber surface of the woven Oxford cloth fabric layer. This application features high structural strength, excellent impact resistance, strong interfacial bonding, waterproof and moisture-proof properties, good flame retardancy, permanent antistatic properties, dimensional stability, and moldability. It can meet the impact resistance, abrasion resistance, and tear resistance requirements of armor protection scenarios and is also suitable for ceiling protection in cleanrooms, new energy workshops, etc.

Description

Technical Field

[0001] This invention relates to the field of protective composite materials technology, specifically to a woven Oxford cloth and polypropylene screw extrusion hot melt composite material, its preparation method, and its application. Background Technology

[0002] As the requirements for material performance continue to upgrade in the fields of transportation, special equipment, building protection and indoor safety, roof and armor protective materials that combine structural strength, protective performance, lightweight, flame retardancy, antistatic properties and environmental stability are facing increasingly stringent application demands.

[0003] Currently, traditional protective materials have several significant shortcomings, as follows:

[0004] On the one hand, conventional fabric materials (such as ordinary PVC Oxford cloth) have certain flame retardancy, flexibility and tear resistance, but their surface is prone to dust accumulation, has poor abrasion resistance, weak resistance to high and low temperatures and poor antistatic effect. In machine tool flexible protective armor (such as wall armor and guide rail protective cover) under the long-term conditions of cutting fluid corrosion, metal dust pollution, high temperature chip impact and high-speed reciprocating motion, as well as in special protective scenarios such as clean space and flammable and explosive environments, it is difficult to meet the requirements for long-term safe use. Simple fabric materials lack rigidity and are prone to deformation without support, making them unsuitable as direct roof structural components or armored protective parts. Traditional armored protective covers are mostly composed of multiple stacked metal scales, with hard contact between layers leading to high frictional resistance. This causes vibration and noise during expansion and contraction, further accelerating wear and shortening service life. Some newer structures use accordion-style bellows integrated with "L"-shaped steel sheets, frames, and flexible connectors, which offers some improvement, but still suffers from excessive inertial load, making it difficult to adapt to high-speed and high-acceleration conditions. This limits the acceleration and maximum operating speed of machine tools, ultimately affecting the overall performance of high-speed machine tools. Furthermore, for long-stroke and ultra-long-axis machine tools, traditional stacked metal (such as stainless steel and aluminum alloy) armored protective covers have many layers and are heavy, typically operating at speeds of only 20-80 m / min, far lower than the 200 m / min of flexible accordion-style protective covers. This places a significant burden on the guide rails and drive system, failing to meet the current application requirements for high-speed (200 m / min) machine tool protection and long strokes exceeding 4 meters.

[0005] Traditional steel frame materials often use ordinary PVC or rubber-coated fabrics. Ordinary PVC materials have poor temperature resistance, insufficient flexural strength, and are prone to brittleness at low temperatures. When exposed to high-temperature metal chips, they are easily burned through or stuck together. Ordinary rubber materials are prone to swelling, hardening, and even cracking after prolonged contact with oily cutting fluids. While composite systems of stainless steel armor plates with nylon / three-proof fabric, aramid, or ultra-high molecular weight polyethylene (UHMWPE) have excellent impact resistance, they each have practical problems such as poor adaptability to different scenarios and high cost.

[0006] On the other hand, while traditional plastic sheets, coated composite materials, and foamed composite ceiling materials possess a certain degree of formability and protection, they generally suffer from insufficient toughness, weak impact resistance, brittleness, low interfacial strength with fabrics, easy delamination, and short service life. Some materials achieve antistatic properties by adding antistatic agents, but such antistatic effects depend on environmental humidity and are prone to migration, failure, and insufficient durability, making it difficult to meet the stringent requirements for permanent antistatic properties in new energy cleanrooms, rail transit, electronic cleanrooms, and explosion-proof environments.

[0007] In practical applications such as vehicle roofs, rail transit interiors, special vehicle armor protection, and building ceilings, materials often need to simultaneously meet multiple performance indicators, including impact resistance, wear resistance, waterproofing and moisture resistance, flame retardancy and low smoke, sound and heat insulation, dimensional stability, and permanent antistatic properties. In existing technologies, the key to structural composites of high-strength polyester or polyamide woven fabrics and polypropylene membranes lies in achieving real-time thermal bonding through processes such as injection molding, casting, and lamination to prepare composite protective materials that combine flexible reinforcement and rigid protection. However, related research and products are still relatively scarce. Conventional composite processes often use adhesive bonding, but polypropylene materials have low surface energy, making effective bonding difficult. Furthermore, adhesive bonding methods suffer from drawbacks such as poor environmental friendliness, insufficient heat resistance, easy delamination at high temperatures, and low production efficiency, failing to meet the demands of continuous industrial production.

[0008] Therefore, developing a protective material that is a composite of woven fabric reinforced with polypropylene membrane, has high structural strength, excellent impact resistance, flame retardancy and antistatic properties, strong interfacial bonding, can be molded, and is suitable for armor and roofs, along with an efficient, stable, and environmentally friendly preparation method, has become an urgent technical challenge to be solved in this field. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the existing defects and provide a woven Oxford cloth and polypropylene screw extrusion hot melt composite material, its preparation method and application, so as to solve the problems involved in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a woven Oxford cloth and polypropylene screw extrusion hot melt composite material, wherein the composite material is formed by screw extrusion hot melt bonding of a polypropylene film layer and a woven Oxford cloth fabric layer. At the interface between the polypropylene film layer and the woven Oxford cloth fabric layer, the polypropylene film layer enters the fiber gaps of the woven Oxford cloth fabric layer to form a penetration embedding zone, and / or the polypropylene film layer forms a coating structure on the fiber surface of the woven Oxford cloth fabric layer, thereby forming a non-planar mechanical locking structure extending along the thickness direction of the woven Oxford cloth fabric layer at the interface between the polypropylene film layer and the woven Oxford cloth fabric layer, restricting the relative slippage between the layers, and maintaining the structural stability of the composite material under bending and impact.

[0011] Furthermore, the matrix resin of the polypropylene film layer is selected from at least one of homopolymer polypropylene, block copolymer polypropylene, and random copolymer polypropylene; the mass fraction of the polypropylene film layer in the composite material is 50%-90%, and the thickness of the polypropylene film layer is 0.2-1.0 mm;

[0012] Alternatively, a polyethylene film layer may be provided between the polypropylene film layer and the woven Oxford cloth fabric layer;

[0013] The polyethylene film layer is metallocene low molecular weight polyethylene.

[0014] Furthermore,

[0015] The polypropylene membrane layer also includes modifiers: 0.5-15% by mass of reinforcing filler and 1-20% by mass of functional additives in the polypropylene membrane layer;

[0016] The functional additives include antistatic agents, flame retardants, compatibilizers, and antioxidants; the reinforcing filler is selected from at least one of glass fiber, whiskers, carbon fiber, carbon nanotubes, and graphene, and the length of the reinforcing filler is 3 mm-10 mm and the diameter is 10 μm-20 μm.

[0017] The antistatic agent is selected from at least one of carbon black, graphene and carbon nanotubes, the flame retardant is selected from phosphate ester flame retardants, the amount of flame retardant added is 25%-35% of the mass of the matrix resin, the antioxidant is selected from hindered phenolic antioxidants, and the compatibilizer is maleic anhydride grafted polyolefin.

[0018] Furthermore, the woven Oxford cloth fabric layer is made of at least one of polyester, nylon, and aramid, with a yarn density of 8.4-66.7 tex, a fiber density of 160 D-1680 D, and a weight of 100-500 g / m². 2 ;

[0019] The woven Oxford cloth fabric layer is treated with functional auxiliaries, which include at least one of dyes, stiffening agents, antistatic agents, flame retardants, antibacterial agents, and waterproof, oil-proof, and stain-resistant auxiliaries.

[0020] The stiffening agent is selected from at least one of anionic vulcanized polyester resin or polyurethane dispersion without free isocyanate groups; the antistatic agent is selected from weakly anionic modified polymers; the flame retardant is selected from cyclic phosphonates or nitrogen-containing organic phosphates; the antibacterial agent is selected from isothiazolinone or benzisothiazolinone; and the waterproof, oil-proof, and stain-proof three-proof additives are selected from carbon hexafluoropolymers or fluorine-free organic polymers.

[0021] A method for preparing a screw-extruded hot-melt composite material of woven Oxford cloth and polypropylene.

[0022] (1) Raw material pretreatment

[0023] The raw materials for the woven nylon Oxford cloth layer and the polypropylene film layer are pretreated.

[0024] (2) Screw extrusion casting composite molding;

[0025] A single-screw extrusion casting laminating machine is used. The pre-treated woven nylon Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the nylon Oxford cloth is free from deviation and wrinkles and has uniform tension.

[0026] The pretreated polypropylene film material is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0027] Barrel temperature control in sections: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 210-215 ℃, and head temperature 210-220 ℃;

[0028] Screw speed: 100-140 r / min;

[0029] Melt pressure: 8-12 MPa

[0030] Casting speed: 2.5-6 m / min

[0031] Cast film cooling roller temperature: 40-50 ℃

[0032] After the polypropylene raw material is heated and melted by a screw extruder, it is uniformly extruded through the die head to form a continuous polypropylene melt film, which is directly cast and covered on the surface of the uniformly moving woven nylon Oxford cloth. The melt film is in full contact with the surface of the nylon Oxford cloth, melts and wets, and penetrates into the pores of the nylon Oxford cloth. After being cooled and shaped by the cooling roller, the two layers of materials are thermally melted and integrated to form a two-layer flexible composite structure.

[0033] (3) Cooling, shaping and winding

[0034] The composite material is further cooled by a cooling roller assembly at a temperature of 40-50 ℃ to completely solidify and shape it, eliminating the internal stress generated during the composite process and ensuring that the material is flat, free from warping, and tightly bonded between layers. Subsequently, it is evenly wound up by a winding device with the winding tension controlled at 6-9 N / m to avoid material stretching deformation or loosening between layers during the winding process.

[0035] Furthermore, the process of screw extrusion casting composite molding (2) is as follows:

[0036] A single-screw extrusion casting laminating machine is used. The pre-treated woven nylon Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the nylon Oxford cloth is free from deviation and wrinkles and has uniform tension. The tension is controlled at 5-8 N / m.

[0037] The pretreated polypropylene film material is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0038] Barrel temperature control in sections: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 210-215 ℃, and head temperature 210-220 ℃;

[0039] Screw speed: 80-120 r / min;

[0040] Melt pressure: 8-12 MPa

[0041] Casting speed: 2-6 m / min

[0042] Cast film cooling roller temperature: 35-45℃

[0043] The pretreated polyethylene film material is fed into the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0044] Barrel temperature control in sections: Zone 1 155-165 ℃, Zone 2 170-180 ℃, Zone 3 185-195 ℃, Zone 4 195-205 ℃, head temperature 200-215 ℃;

[0045] Screw speed: 80-120 r / min;

[0046] Melt pressure: 6-10 MPa

[0047] Casting speed: 2-6 m / min

[0048] Cast film cooling roller temperature: 30-40℃

[0049] Polyethylene and polypropylene raw materials are heated and melted separately in a single-screw extruder, and then uniformly extruded through a casting die to form a continuous melt film. After being cooled to a suitable temperature for composite application by directional air cooling, the melt film is directly cast and stacked onto the surface of a uniformly moving woven nylon Oxford cloth. The polyethylene melt film is in full contact with the surface of the nylon Oxford cloth, melts and penetrates into the pores of the nylon Oxford cloth, and the polypropylene melt film follows closely behind, covering the top layer. Subsequently, the material is cooled and rolled by a three-roll calender to achieve a thermally melted composite of the three layers, ultimately forming a three-layer flexible composite structure.

[0050] Furthermore,

[0051] The overall thickness of the composite material is 0.35 mm to 1.5 mm, of which the thickness of the polypropylene film layer is 0.2 mm to 1.0 mm, and the thickness deviation at various points on the composite material surface is no greater than 0.05 mm.

[0052] Alternatively, the antistatic agent in the polypropylene film layer can be added to the polypropylene film layer raw material for blending modification, or the antistatic agent can be sprayed after the composite material is prepared.

[0053] When applying the antistatic agent, prepare a spray solution with a mass percentage concentration of 2%-10% using an ethanol aqueous solution as the solvent. The ethanol in the ethanol aqueous solution should account for 50%-90% of the mass. The spraying should be completed using one of the following methods: airflow atomization, ultrasonic atomization, or electrostatic spraying.

[0054] Furthermore,

[0055] The woven Oxford cloth fabric layer undergoes a pre-stiffening pretreatment, which may be performed using one of the following processes: padding, foaming, spraying, or coating. During the pretreatment, the liquid content is controlled to be 20%-100%, and the dry weight gain is 20 g / m². 2 -100 g / m 2 After pretreatment, the material undergoes continuous drying and baking processes.

[0056] Furthermore,

[0057] The woven Oxford cloth fabric layer is pre-treated with antistatic pretreatment, using either padding or spraying processes. The antistatic agent has a dry weight gain of 0.5%-5% of the fabric's own weight. After treatment, it is dried at a low temperature of 100 ℃.

[0058] Alternatively, the woven Oxford cloth fabric layer is pre-treated with antistatic pretreatment, and an electrostatic yarn weaving process is selected. During weaving, the spacing between electrostatic weft yarns is controlled to be ≤1 cm. The electrostatic weft yarns are single yarns or ply yarns, and the material is stainless steel, tin-plated copper wire or silver-plated copper wire, with a diameter of 0.05-0.20 mm.

[0059] Alternatively, the woven Oxford cloth fabric layer may be pre-treated with flame retardant impregnation, with the dry weight gain of the flame retardant being 10 g / m². 2 -60 g / m 2 After impregnation and rolling, the product undergoes drying and baking to set its shape.

[0060] Alternatively, the woven Oxford cloth fabric layer may undergo antibacterial post-treatment, using either air spraying or electrostatic spraying, with the antibacterial agent's dry weight gain being 0.05%-2% of the fabric mass. After application, it may be treated with natural air drying or low-temperature drying processes.

[0061] Alternatively, the woven Oxford cloth fabric layer undergoes a three-proof post-treatment. The three-proof auxiliaries are uniformly applied to the fabric surface through one of the following processes: spraying, foaming, or padding. After hot air drying and baking to cure into a film, the dry weight gain of the three-proof auxiliaries is controlled to be 20 g / m². 2 -100 g / m 2 .

[0062] Application of woven Oxford cloth and polypropylene screw extrusion hot melt composite material

[0063] The composite material is used to prepare protective armor or electrostatic protective canopy. The composite material is preheated by at least one of hot air, infrared, and roller methods. The preheating temperature is 40-120 ℃ and the traction speed is 0.5-1 m / min. The preheated composite material is oriented and folded by a heatable folding machine to obtain an electrostatic protective canopy. After cooling and shaping, it is integrated with stainless steel armor plates or aluminum alloy armor plates to obtain protective armor.

[0064] Compared with the prior art, the beneficial effects of the present invention are:

[0065] This application uses Oxford cloth as the reinforcing skeleton and polypropylene film as the structural surface layer. The composite material has high tensile strength, tear resistance, impact resistance, and wear resistance, and can simultaneously meet the dual requirements of armor protection and roof structure support. It employs a hot-melt adhesive-free composite process, where the PP film melts upon heating and fully penetrates the pores of the Oxford cloth. After cooling, it forms a dual bond of mechanical interlocking and chemical bonding, ensuring no delamination at high temperatures, aging resistance, and a long service life. Antistatic properties are achieved through a continuous conductive network of metal wires, which is independent of environmental humidity, does not migrate, and does not fail; the surface resistivity can be stably controlled at 10 ohms. 6 -10 9 Ω is suitable for harsh environments such as explosion-proof, electronic cleanroom, and vehicle interiors.

[0066] This application features high structural strength, excellent impact resistance, strong interfacial bonding, waterproof and moisture-proof properties, good flame retardancy, permanent antistatic properties, dimensional stability, and moldability. It meets the impact resistance, abrasion resistance, and tear resistance requirements of armor protection applications and is suitable for ceiling protection in cleanrooms and new energy workshops. The process is simple, highly controllable, highly efficient, environmentally friendly, and solvent-free, enabling continuous industrial production. The resulting composite material exhibits tight interlayer bonding, no bubbles, no delamination or warping, and stable mechanical properties and protective functions. Attached Figure Description

[0067] Figure 1 These are SEM images of the warp and weft sections of the composite material of this invention;

[0068] Figure 2 These are SEM images of the warp and weft sections of the composite material of this invention;

[0069] Figure 3 A photograph showing the stiffness of the Oxford cloth after the stiffening treatment according to the present invention.

[0070] Figure 4 Photograph of the appearance of the polyester Oxford cloth fabric in which the electrostatic fibers of this invention are implanted;

[0071] Figure 5 This is an evaluation diagram of the explosion-proof and rain-resistant performance of the composite material fabric of the present invention;

[0072] Figure 6 This is a photograph of a high-speed machine tool wall-mounted armor protector prepared from the composite material of this invention.

[0073] Figure 7 This is a schematic diagram of the high-speed machine tool wall-type armor protection structure prepared from the composite material of the present invention;

[0074] Figure 8 This is a photograph of an energy electrostatic protection canopy prepared from the composite material of this invention, showing its actual application.

[0075] Figure 9 This is a schematic diagram of the new energy electrostatic protection canopy structure prepared from the composite material of the present invention. Detailed Implementation

[0076] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0077] Example 1:

[0078] A flexible protective material made of woven Oxford cloth and polypropylene screw extrusion cast composite film has a three-layer structure, consisting of, from top to bottom: a polypropylene cast composite film layer, a metallocene low molecular weight polyethylene (mLLDPE) film layer, and woven nylon Oxford cloth.

[0079] Its preparation method includes the following steps:

[0080] (1) Raw material selection and specification determination

[0081] Polypropylene cast composite film layer (top layer): The raw material is homopolymer polypropylene granules (MFR=15-25 g / 10min, 190 ℃ / 2.16kg), with 0.8 wt% antistatic agent added as a functional additive to ensure good antistatic performance of the cast film; after casting, the film thickness is controlled at 0.30 mm, which plays a protective role of wear resistance, water resistance, weather resistance and self-cleaning, while achieving a firm composite with metallocene low molecular weight polyethylene film layer.

[0082] Polyethylene film layer (intermediate buffer layer): The raw material is metallocene low molecular weight polyethylene granules with a melt flow rate (MFR) of 15-20 g / 10min (test conditions: 130 ℃, 2.16 kg). After casting, the film thickness is controlled at 0.20 mm. This polyethylene film layer can provide protection with low temperature resistance, bending resistance, and high cushioning. At the same time, it can achieve a strong hot-melt composite with woven nylon Oxford cloth, and is suitable for the preparation process of an overall three-layer composite structure.

[0083] Woven nylon Oxford cloth layer: Woven nylon Oxford cloth with an areal density of 260 g / m² is selected as the reinforcing layer. 2 With a thickness of 0.35 mm, radial tensile strength ≥350 N / 5cm, and latitudinal tensile strength ≥320 N / 5cm, it has excellent flexibility, tear resistance, and abrasion resistance. As a reinforcing base for flexible protective materials, it ensures the overall mechanical strength and flexibility of the material.

[0084] (2) Raw material pretreatment

[0085] Polypropylene granule pretreatment: Homopolymer polypropylene granules and antistatic agent are placed in a high-speed mixer and mixed at 60-70 ℃ for 3-5 min to ensure that the antistatic agent is evenly dispersed in the polypropylene granules; then the mixed raw materials are sent to an 80 ℃ drying room to dry for 1.5-2 h to remove trace amounts of moisture from the raw materials and avoid defects such as melt foaming and pinholes in the film layer during screw extrusion.

[0086] Polyethylene granule pretreatment: Place the low molecular weight metallocene granules in a 65 ℃ oven and dry for 1.5-2 h to remove trace amounts of moisture from the raw materials and avoid defects such as melt bubbling and film bubbles during screw extrusion.

[0087] Pretreatment of woven nylon Oxford cloth: The woven nylon Oxford cloth is placed in an open-width drying device and continuously moved radially for 10-20 minutes to remove the internal moisture of the fabric (control the moisture content <0.05%). At the same time, the internal stress generated during the fabric production process is eliminated to prevent wrinkles and delamination in the subsequent lamination process and to ensure the dimensional stability of the laminated material.

[0088] (3) Single-screw extrusion casting composite molding

[0089] A single-screw extrusion casting laminating machine is used. The pre-treated woven nylon Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the nylon Oxford cloth is free from deviation and wrinkles and has uniform tension (tension controlled at 5-8 N / m).

[0090] The pretreated polypropylene mixture is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0091] 1) Segmented temperature control of the barrel: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 210-215 ℃, and head temperature 210-220 ℃;

[0092] 2) Screw speed: 80-120 r / min;

[0093] 3) Melt pressure: 8-12 MPa

[0094] 4) Casting speed: 2-6 m / min

[0095] 5) Temperature of the casting film cooling roller: 35-45℃

[0096] The pretreated metallocene low molecular weight polyethylene granules are fed into the hopper of a single-screw extruder. The screw extrusion process parameters are set as follows:

[0097] 1) Segmented temperature control of the barrel: Zone 1 155-165 ℃, Zone 2 170-180 ℃, Zone 3 185-195 ℃, Zone 4 195-205 ℃, and head temperature 200-215 ℃;

[0098] 2) Screw speed: 80-120 r / min;

[0099] 3) Melt pressure: 6-10 MPa

[0100] 4) Casting speed: 2-6 m / min

[0101] 5) Temperature of the casting film cooling roller: 30-40℃

[0102] Polyethylene and polypropylene raw materials are heated and melted separately in a single-screw extruder, and then uniformly extruded through a casting die to form a continuous melt film. After being cooled to a suitable temperature for composite application by directional air cooling, the melt film is sequentially cast and stacked directly onto the surface of a uniformly moving woven nylon Oxford cloth. The polyethylene melt film fully contacts and melts into the nylon Oxford cloth surface, penetrating the fabric pores, followed by the polypropylene melt film covering the top layer. Subsequently, the material is cooled and rolled in a three-roll calender to achieve a thermally melted integrated composite of the three layers, ultimately forming a three-layer flexible composite structure of "polypropylene cast film layer + metallocene polyethylene cast film layer + woven nylon Oxford cloth layer".

[0103] (4) Cooling, shaping and winding

[0104] After verification, the material is further cooled by a three-roll calender and cooling roller assembly (three-roll calender temperature 60-85 ℃, cooling roller assembly temperature 30-40 ℃) to completely solidify and shape it, eliminate the internal stress generated during the composite process, and ensure that the material is flat, without warping, and has a tight interlayer bond. Then, it is wound up at a uniform speed by a winding device with a winding tension of 6-9 N / m to avoid material stretching deformation or interlayer loosening during the winding process.

[0105] (5) Post-processing

[0106] After cooling and shaping, the composite material is trimmed, rolled up or slit and cut. It is then bent, trimmed, sewn and assembled according to the needs of the armor components to obtain the finished product of flexible armor protective material made of woven nylon Oxford cloth and polypropylene and polyethylene screw extrusion cast composite film.

[0107] The flexible protective material prepared in this embodiment has a strong three-layer structure with an interlayer peel strength ≥15 N / 2.5cm, and is free of delamination, bubbles, and pinholes. It combines the high flexibility, high tensile strength, and tear resistance of woven nylon Oxford cloth with the waterproof, weather-resistant, easy-to-clean, and corrosion-resistant properties of polypropylene cast film. It also features the low-temperature resistance and high cushioning performance of polyethylene. The material is soft and flexible with a bending radius ≤5 cm, and is not brittle or broken. It can withstand environmental temperatures of -30 to 80 ℃ and is suitable for machine tool protective armor, machining equipment protective plates, and structural protective components.

[0108] Example 2:

[0109] A flexible protective material consisting of a woven Oxford cloth and a polypropylene screw extrusion cast composite film has a two-layer structure, consisting of a polypropylene cast composite film layer (upper surface layer) and a woven nylon Oxford cloth layer (lower layer) from top to bottom. The two layers are thermally melted and integrally composited through a screw extrusion cast process, resulting in a flexible material suitable for various flexible protective scenarios.

[0110] Its preparation method includes the following steps:

[0111] (1) Raw material selection and specification determination

[0112] Woven Oxford cloth: Made of woven Oxford cloth, the fabric structure is plain weave, with an areal density of 250 g / m², a thickness of 0.36 mm, a radial tensile strength ≥400 N / 5cm, and a weft tensile strength ≥380 N / 5cm. It has excellent flexibility, tear resistance and abrasion resistance, and serves as a reinforcing base for flexible protective materials, ensuring the overall mechanical strength and flexibility of the material.

[0113] Polypropylene cast composite film layer (top layer): The raw material is random copolymer polypropylene granules (MFR=15-25 g / 10min, 190 ℃ / 2.16kg), with 1.0% antioxidant 1010 and 0.5% UV stabilizer added. After casting, the film thickness is controlled to 0.50 mm, which improves the aging and UV resistance of the material. It is suitable for flexible protection scenarios for long-term outdoor use, and at the same time achieves a strong composite with nylon Oxford cloth.

[0114] (2) Raw material pretreatment

[0115] Pretreatment of woven Oxford cloth: The woven Oxford cloth is placed in an open-width drying device and continuously moved radially for 15-30 minutes to remove the internal moisture of the fabric (control the moisture content <0.05%). At the same time, the internal stress generated during the fabric production process is eliminated to prevent wrinkles and delamination during subsequent lamination and to ensure the dimensional stability of the laminated material.

[0116] Polypropylene granule pretreatment: Homopolymer polypropylene granules are placed together with antioxidants and UV stabilizers in a high-speed mixer and mixed at 60-70 ℃ for 3-5 min to ensure that the processing aids are evenly dispersed in the polypropylene granules; then the mixed raw materials are placed in an 80 ℃ oven to dry for 1.5-2 h to remove trace amounts of moisture from the raw materials and avoid defects such as melt foaming and pinholes in the film layer during screw extrusion.

[0117] (3) Screw extrusion casting composite molding

[0118] A single-screw extrusion casting laminating machine is used. The pre-treated woven Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the Oxford cloth is free from deviation and wrinkles and has uniform tension (tension control is 5-8 N / m).

[0119] The pretreated polypropylene mixture is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0120] 1) Segmented temperature control of the barrel: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 210-215 ℃, and head temperature 210-220 ℃;

[0121] 2) Screw speed: 100-140 r / min;

[0122] 3) Melt pressure: 8-12 MPa

[0123] 4) Casting speed: 2.5-6 m / min

[0124] 5) Temperature of the casting film cooling roller: 40-50℃

[0125] After the polypropylene raw material is heated and melted by a screw extruder, it is uniformly extruded through the die head to form a continuous polypropylene melt film. This film is directly cast and covered on the surface of a uniformly moving woven nylon Oxford cloth. The melt film is in full contact with the surface of the nylon Oxford cloth, melts and impregnates it, and penetrates into the pores of the nylon Oxford cloth. After being cooled and shaped by a cooling roller, the two layers of materials are thermally melted and integrated to form a two-layer flexible composite structure of "polypropylene cast film layer + woven nylon Oxford cloth".

[0126] (4) Cooling, shaping and winding

[0127] The composite material is further cooled by a cooling roller assembly (cooling temperature 40-50 ℃) to completely solidify and shape it, eliminating the internal stress generated during the composite process and ensuring that the material is flat, without warping, and with tight interlayer bonding. Then, it is evenly wound up by a winding device with the winding tension controlled at 6-9 N / m to avoid material stretching deformation or interlayer loosening during the winding process.

[0128] (5) Post-processing

[0129] After the composite roll is wound up, the edges are trimmed to remove irregular parts and ensure that the width of the roll is uniform. According to the actual needs of flexible protective products, the composite roll is cut into the corresponding size, and can be bent, wound or bent twice as needed to flexibly form the product, and finally the finished product of flexible protective material for woven nylon Oxford cloth and polypropylene screw extrusion cast composite film is obtained.

[0130] The flexible protective material prepared in this embodiment has a strong bond between its layers, with an interlayer peel strength ≥18 N / 2.5 cm. The product surface is free of defects such as delamination, bubbles, and pinholes. This material combines the high flexibility, high tensile strength, tear resistance, and abrasion resistance of woven nylon Oxford cloth with the waterproof, weather-resistant, self-cleaning, and corrosion-resistant properties of polypropylene cast film. The material is soft and flexible with a bending radius ≤5 cm. It does not crack or break during bending and has excellent aging resistance. It can withstand environmental temperatures of -20 to 100 ℃ and can be used for a long time in flexible protective armor, equipment protective covers, vehicle flexible protective components, outdoor flexible protective structures, and other fields.

[0131] Figure 1 The images are SEM images of the warp and weft sections of the composite material. (a) and (c) are the radial sections at 30x magnification, and (b) and (d) are the weft sections at 250x magnification. The average thickness of the PP film layer is 0.4 mm, the average thickness of the PET fabric layer is 0.25 mm, and the average total thickness of the composite material is 0.65 mm.

[0132] Figure 2The images are SEM images of the warp and weft sections of the composite material. (a) and (c) are the radial sections at 30x magnification, and (b) and (d) are the weft sections at 250x magnification. The average thickness of the PP film is 0.4 mm, the average thickness of the double-sided nylon Oxford cloth is 0.7 mm, and the average thickness of the composite material is 1.1 mm.

[0133] The composite polypropylene membrane layer possesses specific mechanical properties to meet active protection requirements. The performance indicators and corresponding test standards are as follows: tensile strength 20-50 MPa (test standard: ISO 527-2, test speed: 50 mm / min), elongation at break 30%-600% (test standard: ISO 527-2, test speed: 50 mm / min), flexural strength 20-50 MPa (test standard: ISO 178, test speed: 2.0 mm / min), flexural modulus 800-1500 MPa (test standard: ISO 178, test speed: 2.0 mm / min), and cantilever beam notched impact strength 15-60 KJ / m². 2 (Test standard: ISO 180, test temperature: 23 ℃). These performance indicators are jointly determined by the selection of the polypropylene film matrix resin and the compounding ratio of fillers and additives. They are highly compatible with the overall active protective performance of the composite material, laying the core material foundation for the final product to achieve excellent impact resistance, bending resistance, and structural stability. At the same time, these performance requirements also force precise coordination of the screw extrusion and hot-melt composite processes and equipment parameters, ensuring uniform and controllable film forming quality and allowing the film's mechanical properties to precisely meet the usage requirements of end-use protective equipment.

[0134] Figure 3 The photos show the stiffness of Oxford cloth after stiffening treatment. The treated fabric was cut into samples of 1.5cm × 30cm. Multiple samples were connected end to end in a W-shape. There were no clamping devices in the middle of the samples. Under reciprocating stretching, the samples could achieve stable self-support, which directly demonstrated the structural stability and stiffness performance of the fabric after stiffening treatment.

[0135] Figure 5 The following are evaluation charts for the rainproof performance of composite material fabrics: (a) and (c) are spray tests on untreated and three-proof finished fabrics, respectively; (b) and (d) are the results after the tests. According to the standard in the right figure, the untreated fabric is rated as 1-, and the performance after three-proof finished fabric can reach 4+.

[0136] Figure 6 This is a physical image of a high-speed machine tool wall-mounted armor protection device made from composite materials.

[0137] Figure 7 A schematic diagram of the high-speed machine tool wall-type armor protection structure prepared from composite materials:

[0138] 1-Stainless steel armor plate; 2-Composite material; 3-Connecting plate; 4-Pressure plate; 5-Hanging wheel plate.

[0139] Wall-mounted armor protects against high-speed metal debris impacts, is resistant to oil mist and cutting fluid, and features a foldable assembly structure. The application mechanism involves thermoforming composite materials into a folding structure, which is then combined with aluminum alloy or stainless steel armor plates to achieve a flexible yet rigid protection system.

[0140] Figure 8 An actual image of an energy electrostatic protection canopy made from composite materials.

[0141] Figure 9 A schematic diagram of a new energy electrostatic protection canopy structure prepared from composite materials:

[0142] 1-Guide rail; 2-Composite material; 3-Synchronization structure; 4-Anti-collision block; 5-Opening and closing structure.

[0143] The protective canopy prevents static electricity buildup, provides flame retardant safety, and ensures stable large-format dimensions. It is applied in a large-format suspended structure with modular splicing, achieving comprehensive static electricity protection and fire suppression capabilities.

[0144] Comparative Example 1:

[0145] A flexible protective material composed of woven Oxford cloth and polypropylene film is disclosed. It employs the same two-layer structure (upper polypropylene film layer, lower woven nylon Oxford cloth layer) and the same specifications of raw materials as Embodiment 2. The difference lies in the use of a conventional adhesive bonding process (such as high-frequency welding) instead of the screw extrusion casting hot-melt bonding process of this invention. The specific preparation method is as follows:

[0146] (1) Raw material selection and pretreatment

[0147] The raw material specifications and pretreatment methods are completely consistent with those in Implementation 2, namely, using woven Oxford cloth (area density 250 g / m²). 2 Random copolymer polypropylene film (thickness 0.36 mm) was dried and corona treated (polypropylene film) for later use.

[0148] (2) Adhesive bonding and composite molding

[0149] A solvent-based polyurethane adhesive is selected and evenly coated onto the lower surface of the polypropylene film, with the coating amount controlled at 15-20 g / m². 2 Then, the polypropylene film coated with adhesive is aligned and stacked with the woven Oxford cloth, and fed into a laminating machine. The two layers of materials are then pressed and bonded under conditions of 80-90 ℃, 0.3-0.4 MPa, and 3-5 m / min to achieve the composite of the two materials.

[0150] (3) Post-processing

[0151] After the composite material is air-dried for 24 hours to remove solvent residue, it is then trimmed and cut to obtain the finished flexible protective material of Comparative Example 2.

[0152] Performance comparison between Comparative Example 1 and Example 2:

[0153] Comparative Example 1 uses a conventional adhesive bonding process, which, compared to the screw extrusion casting hot melt composite process of Example 2, has the following obvious defects:

[0154] (1) Poor interlayer bonding performance: The interlayer peel strength is only 6-8 N / 2.5cm, which is far lower than ≥18 N / 2.5cm in Example 2. During bending and stretching, delamination and delamination are likely to occur, which cannot meet the long-term use requirements of flexible protection.

[0155] (2) Poor environmental performance: The use of solvent-based adhesives will release harmful solvents during the composite process, polluting the environment. In addition, there are solvent residues in the finished product, which is not suitable for protective scenarios involving human contact or enclosed spaces. This is fundamentally different from the solvent-free and environmentally friendly screw extrusion casting composite process of this invention.

[0156] (3) Low production efficiency: After the glue is bonded, it needs to be dried for a long time to remove the solvent. The production cycle of a single batch is more than 24 hours. However, Example 2 uses continuous screw extrusion casting composite, which can realize continuous production and improve production efficiency by more than 80%.

[0157] (4) Poor flexibility and weather resistance: The adhesive layer is prone to becoming brittle after curing, which leads to a decrease in the overall flexibility of the composite material. The bending radius is ≥10cm, and the adhesive is prone to aging and yellowing. When exposed to the outdoor environment for a long time, the interlayer bonding force will decay rapidly, and the service life is only 1 / 3-1 / 2 of that in Example 2.

[0158] (5) Insufficient waterproof performance: Uneven glue coating can easily lead to defects such as pinholes and missed coating, resulting in a decrease in the waterproof performance of the composite material. However, in Implementation 2, a complete waterproof membrane is formed by polypropylene melt casting and impregnation, resulting in better waterproof performance.

[0159] As can be seen from the above comparative examples, the present invention adopts a screw extrusion casting hot melt composite process, which can significantly improve the interlayer bonding strength, environmental friendliness, production efficiency and comprehensive protective performance of the two-layer materials compared with the conventional glue bonding composite process. It solves the core defects of the conventional composite process and is more suitable for the industrial production and long-term use of flexible protective materials.

[0160] Comparative Example 2:

[0161] A flexible protective material composed of woven Oxford cloth and polypropylene film is disclosed. It employs the same two-layer structure (upper polypropylene film layer, lower woven Oxford cloth layer) and raw materials of the same specifications as in Example 2. The difference lies in the use of a conventional hot-pressing composite process for the polypropylene film and fabric, rather than the screw extrusion casting hot-melt composite process of this invention. The specific preparation method is as follows:

[0162] (1) Raw material selection and pretreatment

[0163] The raw material specifications and pretreatment methods are completely consistent with those in Example 2, namely, woven Oxford cloth (area density 250 g / m²). 2 The random copolymer polypropylene film (thickness 0.36 mm) is dried and corona treated (polypropylene film) for later use; wherein the polypropylene film is a finished film, not the melt film formed by screw extrusion casting of the present invention.

[0164] (2) Conventional hot pressing composite molding

[0165] The pretreated polypropylene film (finished film) and woven nylon Oxford cloth are aligned and stacked in the order of "polypropylene film on top, nylon Oxford cloth on the bottom", and then fed into a flatbed hot press for hot pressing and lamination. The hot pressing process parameters are set as follows:

[0166] 1) Hot pressing temperature: 170-180 ℃, matching the barrel temperature of the screw extrusion casting composite in Example 2;

[0167] 2) Hot pressing pressure: 0.5-0.7 MPa, higher than the casting composite pressure in Example 2;

[0168] 3) Hot pressing time: 20-30 s / batch, which is intermittent hot pressing and cannot be used for continuous production;

[0169] 4) Cooling method: After hot pressing, remove the product and allow it to cool naturally to room temperature to set.

[0170] The surface of the finished polypropylene film is slightly melted by hot pressing, and then bonded to the surface of the woven nylon Oxford cloth to form a two-layer composite structure.

[0171] (3) Post-processing

[0172] After cooling and shaping, the composite material is trimmed and cut to remove burrs and irregular parts, resulting in the finished flexible protective material of Comparative Example 2.

[0173] Performance comparison between Comparative Example 2 and Example 2:

[0174] Comparative Example 2 uses a conventional hot-pressing lamination process for polypropylene film and fabric. Compared with the screw extrusion casting hot-melt lamination process of this invention, its core defects are as follows, further highlighting the technical advantages of this invention:

[0175] (1) The interlayer bonding is not strong and the uniformity is poor: Conventional hot-pressing composite can only slightly melt the surface of the polypropylene finished film. It cannot fully wet and penetrate the pores of the nylon Oxford cloth to form a mechanical interlocking structure, as the screw extrusion casting process of this invention can. Its interlayer peel strength is only 9-11 N / 2.5cm, which is lower than ≥18 N / 2.5cm in Example 2. Moreover, the composite material is prone to local bubbles and loose adhesion, and local delamination is easy to occur during bending.

[0176] (2) Low production efficiency and inability to be continuous: Conventional hot pressing composite is an intermittent production process with a long hot pressing time per batch, and requires manual stacking and material handling. The production efficiency is only less than 30% of the screw extrusion casting continuous composite process in Example 2, which is not suitable for large-scale industrial production and the production cost is significantly higher than that of this invention.

[0177] (3) Poor flexibility and dimensional stability: Local overheating has occurred during the hot pressing process, resulting in uneven melting of the polypropylene film. After cooling, the material is prone to warping and deformation. Moreover, the internal stress of the material cannot be effectively eliminated after hot pressing. The bending radius is ≥8 cm, and the flexibility is lower than that of Example 2 (≤5 cm), which cannot meet the bending and winding requirements of flexible protective materials.

[0178] (4) Limited waterproof performance: There are gaps at the interface between the finished polypropylene film and the nylon Oxford cloth. Hot pressing cannot completely fill the pores of the fabric, which easily leads to water seepage. However, the present invention uses screw extrusion casting to directly cast the polypropylene melt and combine it with the fabric to form a complete and continuous waterproof membrane layer, which has more reliable waterproof performance.

[0179] (5) Poor material consistency: Conventional hot-pressing composite is greatly affected by manual stacking and the uniformity of hot-pressing temperature. The interlayer bonding strength and thickness uniformity of materials in different batches and in different positions of the same batch vary greatly. The screw extrusion casting composite of the present invention is a continuous and automated production process with controllable process parameters, small material size restrictions, good consistency, and a finished product qualification rate of ≥98%, which is much higher than the 85% or less of Comparative Example 2.

[0180] In summary, the screw extrusion casting hot melt composite process of the present invention, compared with the conventional hot pressing composite process of polypropylene film and fabric, not only solves the defects of poor interlayer bonding, low production efficiency and poor consistency of hot pressing composite, but also significantly improves the flexibility, waterproofness and dimensional stability of the material, making it more suitable for the industrial production and actual use needs of flexible protective materials.

[0181] Example 3:

[0182] A flexible protective material made of woven Oxford cloth and polypropylene screw extrusion casting composite has a three-layer structure, consisting of an upper antistatic polyester Oxford cloth layer, a polypropylene casting film layer, and a lower electrostatic metal wire embedded polyester Oxford cloth layer from top to bottom. The three layers are integrally composited by screw extrusion casting and hot-melt bonding, maintaining good flexibility as a whole, and possessing antistatic, high strength, and waterproof protective functions. It is suitable for flexible protective scenarios that require electrostatic protection.

[0183] Its preparation method includes the following steps:

[0184] (1) Raw material selection and specification determination

[0185] 1) Upper Antistatic Polyester Oxford Cloth Layer: Woven polyester Oxford cloth (plain weave) is used, with a surface density of 180 g / m², a thickness of 0.30 mm, a warp tensile strength ≥320 N / 5cm, and a weft tensile strength ≥300 N / 5cm; the fabric undergoes antistatic modification treatment (spun with the addition of 2% antistatic masterbatch), and the surface resistivity is controlled at 10 Ω·cm. 6 -10 9 Ω has permanent antistatic properties and serves as the upper protective layer, providing antistatic, wear-resistant, and tear-resistant effects while ensuring the overall flexibility of the material.

[0186] 2) Polypropylene Cast Film Layer (Intermediate Bonding / Protective Layer): The raw material is homopolymer polypropylene granules (MFR=18-28 g / 10min, 190 ℃ / 2.16kg), with 0.6% PE wax and 0.3% antioxidant 1010 added to improve melt flowability and aging resistance; after casting, the film thickness is controlled at 0.12 mm, serving as the intermediate bonding layer in a three-layer structure to achieve a strong composite of the upper and lower Oxford cloth layers, while also providing waterproof, moisture-proof, and barrier functions.

[0187] 3) Electrostatic metal wire embedded in polyester Oxford cloth layer: Woven polyester Oxford cloth (plain weave) with a surface density of 200g / m² is used. 2 The thickness is 0.32 mm, the warp tensile strength is ≥330 N / 5cm, and the weft tensile strength is ≥310 N / 5cm. During the weaving process of Oxford cloth, electrostatic metal wires are evenly implanted into the fabric. The metal wires are 304 stainless steel wires with a diameter of 0.08 mm, arranged in parallel with a wire spacing of 8 mm to form a continuous conductive network, which further enhances the antistatic properties of the material and serves as a lower reinforcing base to improve the overall mechanical strength of the material.

[0188] (2) Raw material pretreatment

[0189] 1) Pretreatment of antistatic polyester Oxford cloth: Dry the antistatic polyester Oxford cloth in a vacuum oven at 80-90 ℃ for 2-3 h to remove moisture (moisture content <0.05%), eliminate internal stress, and prevent wrinkles and delamination during the composite process.

[0190] 2) Pretreatment of polyester Oxford cloth with embedded antistatic metal wire: Place the polyester Oxford cloth with embedded metal wire in a vacuum oven at 80-90℃ for 2-3 hours to dry and remove moisture. At the same time, check the arrangement of the metal wire to ensure that there is no crossover, no breakage and uniform spacing, so as to avoid the metal wire from shifting and affecting the antistatic performance.

[0191] 3) Polypropylene granule pretreatment: Homopolymer polypropylene granules, PE wax, and antioxidant 1010 are placed in a high-speed mixer and mixed at 65-75 ℃ for 4-6 min to ensure uniform dispersion of the additives; then placed in an 80 ℃ oven to dry for 1.5-2 h to remove trace amounts of moisture and prevent melt foaming and pinholes in the film layer during screw extrusion.

[0192] (3) Screw extrusion casting composite molding

[0193] A single-screw extrusion casting laminator is used to sequentially complete the lamination and compounding of a three-layer structure. The specific operation is as follows:

[0194] 1) Unwinding and positioning: The electrostatic metal wire is implanted into the polyester Oxford cloth as the bottom base. It is laid flat and tensioned by the unwinding device and fed into the composite station at a uniform speed. The tension is controlled at 6-9 N / m to ensure no deviation and no wrinkles.

[0195] 2) Screw extrusion casting: The pretreated polypropylene mixture is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0196] ① Segmented temperature control of the barrel: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 210-215 ℃, and head temperature 210-220 ℃;

[0197] ② Screw speed: 90-130 r / min;

[0198] ③ Melt pressure: 9-13 MPa;

[0199] ④ Casting speed: 4-7 m / min;

[0200] ⑤ Temperature of the casting film cooling roller: 38-48℃.

[0201] 3) Intermediate film layer composite: After the polypropylene raw material is heated and melted by the screw extruder, it is uniformly extruded through the die head to form a continuous polypropylene melt film. It is directly cast and covered on the upper surface of the polyester Oxford cloth by the uniformly moving lower metal wire. The melt film fully wets the pores of the fabric and wraps the metal wire. After being rolled and shaped by a three-roll calender, the polypropylene film and the lower Oxford cloth are thermally melted together.

[0202] 4) Upper layer Oxford cloth lamination: The pretreated upper antistatic polyester Oxford cloth is fed into the three-roll calender through the unwinding device and the upper roller preheating to ensure that the three layers are aligned without misalignment. While hot, the temperature of the three rollers is controlled at 85-95℃ and the pressure is 0.4-0.6 MPa, so that the polypropylene film melts and simultaneously impregnates the pores of the upper and lower layers of antistatic polyester Oxford cloth, realizing the three-layer integrated hot melt lamination.

[0203] (4) Cooling, shaping and winding

[0204] The three-layer composite material is cooled in stages by cooling rollers. First, it is cooled at a medium temperature of 40-50℃, and then at a low temperature of 30-35℃ to completely solidify and shape it, eliminate internal stress, and ensure that the material is flat, without warping, and has a tight bond between layers. Then, it is wound up at a uniform speed by a winding device, with the winding tension controlled at 7-10 N / m to avoid material stretching deformation, loosening between layers, or displacement of metal wires during the winding process.

[0205] (5) Post-processing

[0206] After winding, the composite roll is trimmed to remove irregular edges and ensure uniform width. It is then cut to the appropriate size according to the requirements of flexible protective products. It can be bent, wound, or re-formed as needed. At the same time, the exposed ends of the metal wires are insulated to prevent electrostatic discharge. Finally, a three-layer woven Oxford cloth and polypropylene screw extrusion casting composite flexible protective material is obtained.

[0207] The three-layer flexible protective material prepared in this embodiment has a strong interlayer bond, an interlayer peel strength ≥16 N / 2.5 cm, and is free of delamination, bubbles, and pinholes. It also possesses the dual antistatic properties of an upper antistatic polyester Oxford cloth and a lower metal wire-embedded Oxford cloth, with a surface resistivity stable at 10 N / cm². 6 -10 9 Ω can quickly conduct static electricity, making it suitable for scenarios requiring electrostatic protection, such as electronic cleanrooms and explosion-proof environments. It also possesses the high flexibility, high tensile strength, and tear resistance of polyester Oxford cloth, as well as the waterproof, weather-resistant, and easy-to-clean properties of polypropylene film. It is soft and flexible with a bending radius of ≤6 cm, and it is not brittle or damaged. It can withstand ambient temperatures from -20 to 95℃, making it suitable for applications such as antistatic flexible protective armor, electronic equipment protective sleeves, flexible protective components for explosion-proof environments, and cleanroom protective curtains.

[0208] Example 4:

[0209] A screw-extruded hot-melt composite material of woven Oxford cloth and polypropylene is disclosed. The composite material is formed by screw extrusion hot-melt bonding of a polypropylene film layer and a woven Oxford cloth fabric layer. At the interface between the polypropylene film layer and the woven Oxford cloth fabric layer, the polypropylene film layer enters the fiber gaps of the woven Oxford cloth fabric layer to form a penetration and embedding zone, and / or the polypropylene film layer forms a coating structure on the fiber surface of the woven Oxford cloth fabric layer. This results in a non-planar mechanical locking structure extending along the thickness direction of the woven Oxford cloth fabric layer at the interface between the polypropylene film layer and the woven Oxford cloth fabric layer, which restricts the relative slippage between the layers and maintains the structural stability of the composite material under bending and impact.

[0210] The matrix resin of the polypropylene membrane is selected from at least one of homopolymer polypropylene, block copolymer polypropylene, and random copolymer polypropylene; the mass fraction of the polypropylene membrane in the composite material is 50%-90%, and the thickness of the polypropylene membrane is 0.4-1.0 mm; the polypropylene membrane is used to regulate the melt penetration capacity and the rigidity-flexibility matching relationship of the composite structure: when the mass fraction is less than 50%, the interfacial penetration is insufficient, the bonding force decreases, and the overall rigidity is insufficient; when the mass fraction is greater than 90%, the material rigidity is too high, and the bending performance decreases; this mass ratio can balance the rigidity, toughness and fabric fit of the composite material, and can also avoid the membrane being too thick and causing brittleness or too thin and causing insufficient protective performance, so as to achieve bidirectional functional complementarity between membrane rigidity and fabric toughness, consolidate the comprehensive performance foundation of the composite material from the substrate level, and build a basic support system with complementary double-layer substrate structure and performance coupling.

[0211] A polyethylene film layer is also provided between the polypropylene film layer and the woven Oxford cloth fabric layer;

[0212] The polyethylene film layer is metallocene low molecular weight polyethylene.

[0213] The polypropylene membrane layer also includes modifiers: 0.5-15% by mass of reinforcing filler and 1-20% by mass of functional additives in the polypropylene membrane layer;

[0214] The functional additives include antistatic agents, flame retardants, compatibilizers, and antioxidants; the reinforcing filler is selected from at least one of glass fiber, whiskers, carbon fiber, carbon nanotubes, and graphene, and the length of the reinforcing filler is 3 mm-10 mm and the diameter is 10 μm-20 μm.

[0215] The antistatic agent is selected from at least one of carbon black, graphene, and carbon nanotubes; the flame retardant is a phosphate ester flame retardant, with an addition amount of 25%-35% of the matrix resin mass. After addition, the flame retardant performance of the film layer reaches the UL-94 standard V0 level, and a 1.5 mm thick sample can meet the standard. It has excellent flame retardant characteristics such as self-extinguishing upon removal of the flame and no dripping. The antioxidant is a hindered phenolic antioxidant, and the compatibilizer is maleic anhydride-grafted polyolefin. It is used to simultaneously improve the interfacial bonding force between polypropylene and reinforcing filler and fabric interfaces, solving the technical problems of poor compatibility between polypropylene and filler and fabric layers and easy delamination of composite interfaces. At the same time, it can significantly improve melt penetration stability. Combined with antioxidants and flame retardants, it achieves multiple synergistic improvements in film layer aging resistance, flame retardancy, and structural strength, while further consolidating the bonding stability of the double-sided composite interface, eliminating the industry common problem of mutual restriction between functional modification and composite strength, and achieving simultaneous optimization of film layer modification and interfacial bonding.

[0216] The woven Oxford cloth fabric layer is made of at least one of polyester, nylon, and aramid, with a yarn density of 8.4-66.7 tex, fiber density of 160 D-1680 D, and a weight of 100-500 g / m². 2 The fiber material, yarn density, and thickness of the fabric are highly matched with the hot-melt processing characteristics of the polypropylene film layer, directly determining the smoothness of the hot-melt composite process. The suitable parameter range ensures that the hot-melt polypropylene resin fully and evenly impregnates the fabric yarn, avoiding insufficient impregnation leading to weak bonding or excessive impregnation damaging the fabric fibers. This allows the polypropylene melt to enter the fiber gaps and form a stable mechanical locking structure at the double-layer composite interface, efficiently coupling the mechanical properties of the film layer with the toughness of the fabric, further enhancing the overall mechanical strength and interfacial bonding of the composite material, eliminating delamination and peeling problems, and achieving seamless bonding and bidirectional performance enhancement between the fabric and film layer interfaces.

[0217] The woven Oxford cloth fabric layer is treated with functional auxiliaries, which include at least one of dyes, stiffening agents, antistatic agents, flame retardants, antibacterial agents, and waterproof, oil-proof, and stain-resistant auxiliaries.

[0218] The stiffening agent is selected from at least one of anionic vulcanized polyester resin or polyurethane dispersion without free isocyanate groups. Pretreatment with the stiffening agent imparts basic stiffness to the fabric, which, combined with the rigidity of the polypropylene film layer, achieves a synergistic effect on the overall deformation resistance of the composite material. The antistatic agent is a weakly anionic modified polymer, the flame retardant is a cyclic phosphonate ester or a nitrogen-containing organic phosphate ester, the antibacterial agent is isothiazolinone or benzisothiazolinone, and the waterproof, oil-proof, and stain-resistant additives are hexafluorocarbon-containing or fluorine-free organic polymers. The flame-retardant and antistatic components of the fabric work synergistically with the corresponding additives in the polypropylene film layer to achieve a comprehensive flame-retardant and antistatic effect across the entire composite material, rather than just the localized performance of a single film layer or fabric layer. Simultaneously, fabric pretreatment prevents fabric deformation during hot-melt lamination, ensuring dimensional accuracy of the composite. Ultimately, this achieves a two-way compatibility between fabric function and film layer performance, allowing the dual-layer functions to work synergistically and comprehensively compensate for the performance shortcomings of a single material.

[0219] A method for preparing a screw-extruded hot-melt composite material of woven Oxford cloth and polypropylene.

[0220] (1) Raw material pretreatment

[0221] The raw materials for the woven nylon Oxford cloth layer and the polypropylene film layer or polyethylene film layer are pretreated;

[0222] (2) Screw extrusion casting composite molding (woven nylon Oxford cloth layer and polypropylene film layer);

[0223] A single-screw extrusion casting laminating machine is used. The pre-treated woven nylon Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the nylon Oxford cloth is free from deviation and wrinkles and has uniform tension.

[0224] The pretreated polypropylene film material is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0225] Barrel temperature control in sections: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 205-215 ℃, and head temperature 210-220 ℃;

[0226] Screw speed: 100-140 r / min;

[0227] Melt pressure: 8-12 MPa

[0228] Casting speed: 2.5-6 m / min

[0229] Cast film cooling roller temperature: 40-50 ℃

[0230] After the polypropylene raw material is heated and melted by a screw extruder, it is uniformly extruded through the die head to form a continuous polypropylene melt film, which is directly cast and covered on the surface of the uniformly moving woven nylon Oxford cloth. The melt film is in full contact with the surface of the nylon Oxford cloth, melts and wets, and penetrates into the pores of the nylon Oxford cloth. After being cooled and shaped by the cooling roller, the two layers of materials are thermally melted and integrated to form a two-layer flexible composite structure.

[0231] (3) Cooling, shaping and winding

[0232] The composite material is further cooled by a cooling roller assembly at a temperature of 40-50 ℃ to completely solidify and shape it, eliminating the internal stress generated during the composite process and ensuring that the material is flat, free from warping, and tightly bonded between layers. Subsequently, it is evenly wound up by a winding device with the winding tension controlled at 6-9 N / m to avoid material stretching deformation or loosening between layers during the winding process.

[0233] The process of screw extrusion casting composite molding (2) can also be (woven nylon Oxford cloth layer and polypropylene film layer or polyethylene film layer):

[0234] A single-screw extrusion casting laminating machine is used. The pre-treated woven nylon Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the nylon Oxford cloth is free from deviation and wrinkles and has uniform tension. The tension is controlled at 5-8 N / m.

[0235] The pretreated polypropylene film material is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0236] Barrel temperature control in sections: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 205-215 ℃, and head temperature 210-220 ℃;

[0237] Screw speed: 80-120 r / min;

[0238] Melt pressure: 8-12 MPa

[0239] Casting speed: 2-6 m / min

[0240] Cast film cooling roller temperature: 35-45℃

[0241] The pretreated polyethylene film material is fed into the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows:

[0242] Barrel temperature control in sections: Zone 1 155-165 ℃, Zone 2 170-180 ℃, Zone 3 185-195 ℃, Zone 4 195-205 ℃, head temperature 200-215 ℃;

[0243] Screw speed: 80-120 r / min;

[0244] Melt pressure: 6-10 MPa

[0245] Casting speed: 2-6 m / min

[0246] Cast film cooling roller temperature: 30-40℃

[0247] Polyethylene and polypropylene raw materials are heated and melted separately in a single-screw extruder, and then uniformly extruded through a casting die to form a continuous melt film. After being cooled to a suitable temperature for composite application by directional air cooling, the melt film is directly cast and stacked onto the surface of a uniformly moving woven nylon Oxford cloth. The polyethylene melt film is in full contact with the surface of the nylon Oxford cloth, melts and penetrates into the pores of the nylon Oxford cloth, and the polypropylene melt film follows closely behind, covering the top layer. Subsequently, the material is cooled and rolled by a three-roll calender to achieve a thermally melted composite of the three layers, ultimately forming a three-layer flexible composite structure.

[0248] The overall thickness of the composite material is 0.35mm-1.5mm, of which the thickness of the polypropylene film layer is 0.2mm-1.0mm, and the thickness deviation at various points on the composite material is no greater than 0.05mm. This thickness and width specification are suitable for large-size molding requirements. The extremely small thickness deviation can significantly improve the processing efficiency and finished product qualification rate of subsequent deep processing processes such as integrated protective armor. It solves the technical problems of uneven thickness and easy warping and deformation of traditional composite materials in large-format molding. At the same time, precise thickness control ensures uniform mechanical properties of the composite material throughout, laying a solid process foundation for subsequent functional modification, armor integration and assembly and other processes.

[0249] The antistatic agent for the polypropylene film layer is added to the polypropylene film layer raw material for blending modification, or the antistatic agent is sprayed after the composite material is prepared.

[0250] When applying the antistatic agent, a 2%-10% (w / w) spray solution is prepared using an ethanol-water solution as the solvent. The ethanol content in the ethanol-water solution is 50%-90% by mass. Spraying is performed using one of the following methods: airflow atomization, ultrasonic atomization, or electrostatic spraying. The antistatic properties of the polypropylene film layer are crucial for ensuring the safety and long-term reliability of the composite material. Furthermore, the antistatic properties work synergistically with the interface between the film layer and the fabric layer, as well as the overall mechanical stability: on the one hand, they effectively prevent static electricity buildup from damaging the composite interface structure, preventing localized warping or peeling of the film layer and fabric layer due to electrostatic adsorption and discharge; on the other hand, they ensure that the surface electrical properties of the composite material remain stable under complex conditions such as reciprocating tension, dynamic bending, and external impact, preventing static interference from affecting the continuous and stable performance of the active protection function. This balances safety and long-term performance, providing dual protection against static electricity and structural stability for the long-term stable service of the composite material.

[0251] The woven Oxford cloth fabric layer undergoes a pre-stiffening pretreatment, which may be performed using one of the following processes: padding, foaming, spraying, or coating. During the pretreatment, the liquid content is controlled to be 20%-100%, and the dry weight gain is 20 g / m². 2 -100 g / m 2 After pretreatment, the fabric undergoes continuous drying and baking processes. The pretreatment process and the subsequent hot-melt lamination process work synergistically. On the one hand, it significantly improves the dimensional stability of the fabric under the high-temperature environment of hot-melt lamination, eliminating issues such as fabric thermal shrinkage and deformation displacement, and ensuring the dimensional accuracy of the composite product. On the other hand, the stiffness imparted by the pretreatment to the fabric and the rigidity of the polypropylene film layer mutually support each other, significantly enhancing the overall tensile strength, impact resistance, and structural stability of the composite material. This simultaneously improves the active protection level of the composite material, achieving a dual technical effect of process optimization and performance enhancement, far exceeding the combined effect of a single fabric pretreatment or a single film layer modification. Ultimately, this provides a stable and reliable substrate guarantee for subsequent high-end protective applications.

[0252] The woven Oxford cloth fabric layer undergoes an antistatic pretreatment, using either padding or spraying processes. The antistatic agent's dry weight gain is 0.5%-5% of the fabric's own weight. After treatment, it is dried at a low temperature of 100℃. The treated fabric layer meets the antistatic performance standards, with its surface resistance stably controlled at 10 Ω·cm. 6 Ω-10 9 Ω, the test standard is ASTM D257. This antistatic index matches the antistatic performance of the polypropylene film layer, realizing full-area antistatic properties of the composite material, completely eliminating the blind spots of antistatic properties of a single film layer or a single fabric, fundamentally avoiding interface peeling caused by static electricity, ensuring safe use without hidden dangers, and achieving full-area antistatic protection without dead corners.

[0253] The woven Oxford cloth fabric layer undergoes an antistatic pretreatment, employing an antistatic yarn weaving process. During weaving, the spacing between the antistatic weft yarns is controlled to be ≤1 cm. The antistatic weft yarns are single or ply yarns, made of stainless steel, tin-plated copper wire, or silver-plated copper wire, with a diameter of 0.05-0.20 mm. This can be flexibly adjusted according to the overall strength of the fabric. This weaving process does not damage the original mechanical properties and woven structure of the fabric, and the surface resistance of the fabric remains stable at 10 after treatment. 6 Ω-10 9 Ω, the test standard is ASTM D257; the two antistatic implementation methods can be used alone or in combination, and both can work together with the polypropylene film antistatic system to ensure that the composite material is free from static electricity accumulation throughout the process, improve the dynamic use stability, take into account the long-term antistatic effect and process flexibility, and adapt to the protection needs of multiple scenarios. Figure 4 Photographs showing the appearance of polyester Oxford cloth fabric with electrostatic fibers embedded.

[0254] The woven Oxford cloth fabric layer is pre-treated with flame retardant impregnation, and the dry weight gain of the flame retardant is 10g / m². 2 -60 g / m 2 After impregnation and rolling, the product undergoes drying and baking to set its shape.

[0255] The woven Oxford cloth fabric layer undergoes an antibacterial post-treatment, using either air spraying or electrostatic spraying. The dry weight gain of the antibacterial agent is 0.05%-2% of the fabric mass. After application, it is treated with natural air drying or low-temperature drying. This antibacterial treatment process does not affect the original stiffness, antistatic properties, and flame retardant properties of the fabric. It is compatible and synergistic with other functional systems of the composite material, giving the finished product long-lasting antibacterial and hygienic properties, broadening the application range of the composite material in protective scenarios, and achieving multi-functional composite without interference and balanced performance of various properties.

[0256] The woven Oxford cloth fabric layer undergoes a three-proof treatment. The three-proof additives are uniformly applied to the fabric surface through one of the following processes: spraying, foaming, or padding. After hot air drying and baking to cure into a film, the dry weight gain of the three-proof additives is controlled to be 20 g / m². 2 -100 g / m 2 The treated fabric meets the standards for three-proof performance, with a waterproof rating of level 4 or above, corresponding to the heavy rain spray test standard GB / T 4745-2012 and the hydrostatic pressure test standard ISO 811:2018. It also meets the colorfastness test for chili oil and red wine stains. This three-proof performance does not interfere with the fabric's stiffness, antistatic properties, and flame retardant properties. Combined with the inherent protective properties of the polypropylene film layer, it further enhances the overall stain resistance and liquid penetration resistance of the composite material, effectively extending its service life and strengthening its durability in outdoor and complex working conditions.

[0257] Application of woven Oxford cloth and polypropylene screw extrusion hot melt composite material

[0258] The composite material is used to prepare protective armor or electrostatic protective canopy. The composite material is preheated by at least one of hot air, infrared, and roller methods. The preheating temperature is 40-120 ℃ and the traction speed is 0.5-1 m / min. The preheated composite material is oriented and folded by a heatable folding machine to obtain an electrostatic protective canopy. After cooling and shaping, it is integrated with stainless steel armor plates or aluminum alloy armor plates to obtain protective armor.

[0259] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A woven Oxford cloth and polypropylene screw-extruded hot-melt composite material, characterized in that: The composite material is formed by hot-melt compounding of a polypropylene film layer and a woven Oxford cloth fabric layer through screw extrusion. At the interface between the polypropylene film layer and the woven Oxford cloth fabric layer, the polypropylene film layer enters the fiber gaps of the woven Oxford cloth fabric layer to form a penetration and embedding zone, and / or the polypropylene film layer forms a coating structure on the fiber surface of the woven Oxford cloth fabric layer. This creates a non-planar mechanical interlocking structure at the interface between the polypropylene film layer and the woven Oxford cloth fabric layer that extends along the thickness direction of the woven Oxford cloth fabric layer, restricting relative slippage between the layers and maintaining the structural stability of the composite material under bending and impact.

2. The woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 1, characterized in that: The matrix resin of the polypropylene film layer is selected from at least one of homopolymer polypropylene, block copolymer polypropylene, and random copolymer polypropylene; the mass fraction of the polypropylene film layer in the composite material is 50%-90%. Alternatively, a polyethylene film layer may be provided between the polypropylene film layer and the woven Oxford cloth fabric layer; The polyethylene film layer is metallocene low molecular weight polyethylene.

3. The woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 2, characterized in that: The polypropylene membrane layer also includes modifiers: including reinforcing fillers of 0.5-15% by mass of the polypropylene membrane layer and functional additives of 1-20% by mass of the polypropylene membrane layer; The functional additives also include antistatic agents, flame retardants, compatibilizers, and antioxidants; the reinforcing filler is selected from at least one of glass fiber, whiskers, carbon fiber, carbon nanotubes, and graphene, and the length of the reinforcing filler is 3 mm-10 mm and the diameter is 10 μm-20 μm. The antistatic agent is selected from at least one of carbon black, graphene and carbon nanotubes, the flame retardant is selected from phosphate ester flame retardants, the amount of flame retardant added is 25%-35% of the mass of the matrix resin, the compatibilizer is maleic anhydride grafted polyolefin, and the antioxidant is selected from hindered phenolic antioxidants.

4. The woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 1, characterized in that: The woven Oxford cloth fabric layer is made of at least one of polyester, nylon and aramid, with a yarn density of 8.4-66.7 tex and a fiber density of 160 D-1680 D. The woven Oxford cloth fabric layer is treated with functional auxiliaries, which include at least one of dyes, stiffening agents, antistatic agents, flame retardants, antibacterial agents, and waterproof, oil-proof, and stain-resistant auxiliaries. The stiffening agent is selected from at least one of anionic vulcanized polyester resin or polyurethane dispersion without free isocyanate groups; the antistatic agent is selected from weakly anionic modified polymers; the flame retardant is selected from cyclic phosphonates or nitrogen-containing organic phosphates; the antibacterial agent is selected from isothiazolinone or benzisothiazolinone; and the waterproof, oil-proof, and stain-proof three-proof additives are selected from carbon hexafluoropolymers or fluorine-free organic polymers.

5. The method for preparing the woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to any one of claims 1-4, characterized in that: (1) Raw material pretreatment The raw materials for the woven Oxford cloth layer and the polypropylene film layer are pretreated. (2) Screw extrusion casting composite molding; A single-screw extrusion casting laminating machine is used. The pre-treated woven Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the Oxford cloth is free from deviation, wrinkles and uniform tension. The pretreated polypropylene film material is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows: Barrel temperature control in sections: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 215-220 ℃, and head temperature 210-220 ℃; Screw speed: 100-140 r / min; Melt pressure: 8-12 MPa Casting speed: 2.5-6 m / min Cast film cooling roller temperature: 40-50 ℃ After the polypropylene raw material is heated and melted by the screw extruder, it is uniformly extruded through the die head to form a continuous polypropylene melt film, which is directly cast and covered on the surface of the uniformly moving woven Oxford cloth. The polypropylene melt film is in full contact with the surface of the Oxford cloth, melts and impregnates, and penetrates into the pores of the Oxford cloth. After being cooled and shaped by the cooling roller, the two layers of materials are thermally melted and integrated to form a two-layer flexible composite structure. (3) Cooling, shaping and winding The composite material is further cooled by a cooling roller assembly at a temperature of 40-50 ℃ to completely solidify and shape it, eliminating the internal stress generated during the composite process and ensuring that the material is flat, free from warping, and tightly bonded between layers. Subsequently, it is evenly wound up by a winding device with the winding tension controlled at 6-9 N / m to avoid material stretching deformation or loosening between layers during the winding process.

6. The method for preparing the woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 5, characterized in that: The process of screw extrusion casting composite molding (2) is as follows: A single-screw extrusion casting laminating machine is used. The pre-treated woven nylon Oxford cloth is used as the lower base layer. It is laid flat and tensioned by the unwinding device and fed into the laminating station of the casting laminating machine at a uniform speed to ensure that the Oxford cloth is free from deviation and wrinkles and has uniform tension. The tension is controlled at 5-8 N / m. The pretreated polypropylene film material is added to the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows: Barrel temperature control in sections: Zone 1 175-185 ℃, Zone 2 190-200 ℃, Zone 3 205-215 ℃, Zone 4 215-220 ℃, and head temperature 210-220 ℃; Screw speed: 80-120 r / min; Melt pressure: 8-12 MPa Casting speed: 2-6 m / min Cast film cooling roller temperature: 35-45℃ The pretreated polyethylene film material is fed into the hopper of a single-screw extruder, and the screw extrusion process parameters are set as follows: Barrel temperature control in sections: Zone 1 155-165 ℃, Zone 2 170-180 ℃, Zone 3 185-195 ℃, Zone 4 195-215 ℃, head temperature 200-215 ℃; Screw speed: 80-120 r / min; Melt pressure: 6-10 MPa Casting speed: 2-6 m / min Cast film cooling roller temperature: 30-40℃ After being heated and melted by a single-screw extruder, polyethylene and polypropylene raw materials are uniformly extruded through a die head to form a continuous melt film. After being cooled to a suitable temperature for composite application by directional air cooling, the melt film is sequentially cast and stacked directly onto the surface of the uniformly moving woven Oxford cloth. The polyethylene melt film is in full contact with the surface of the Oxford cloth, melts and impregnates it, and penetrates into the pores of the Oxford cloth. The polypropylene melt film follows closely behind and covers the top layer. Subsequently, it is cooled, rolled and shaped by a three-roll calender to achieve the thermal fusion composite of the three layers, and finally forms a three-layer flexible composite structure.

7. The method for preparing the woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 5, characterized in that: The overall thickness of the composite material is 0.35 mm-1.5 mm, of which the thickness of the polypropylene film layer is 0.2 mm-1.0 mm, and the thickness deviation at various points on the composite material surface is no greater than 0.05 mm. Alternatively, the antistatic agent in the polypropylene film layer can be added to the polypropylene film layer raw material for blending modification, or the antistatic agent can be sprayed after the composite material is prepared. When applying the antistatic agent, prepare a spray solution with a mass percentage concentration of 2%-10% using an ethanol aqueous solution as the solvent. The ethanol in the ethanol aqueous solution should account for 50%-90% of the mass. The spraying should be completed using one of the following methods: airflow atomization, ultrasonic atomization, or electrostatic spraying.

8. The method for preparing the woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 5, characterized in that: The woven Oxford cloth fabric layer undergoes a pre-stiffening pretreatment, which may be performed using one of the following processes: padding, foaming, spraying, or coating. During the pretreatment, the liquid content is controlled to be 20%-100%, and the dry weight gain is 20 g / m². 2 -100 g / m 2 After pretreatment, the material undergoes continuous drying and baking processes.

9. The method for preparing the woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to claim 5, characterized in that: The woven Oxford cloth fabric layer is pre-treated with antistatic pretreatment, using either padding or spraying processes. The antistatic agent has a dry weight gain of 0.5%-5% of the fabric's own weight. After treatment, it is dried at a low temperature of 100 ℃. Alternatively, the woven Oxford cloth fabric layer is pre-treated with antistatic pretreatment, and an electrostatic yarn weaving process is selected. During weaving, the spacing between electrostatic weft yarns is controlled to be ≤1 cm, and the electrostatic weft yarns are selected as single yarns or ply yarns. Alternatively, the woven Oxford cloth fabric layer may be pre-treated with flame retardant impregnation, with the dry weight gain of the flame retardant being 10 g / m². 2 -60 g / m 2 After impregnation and rolling, the product undergoes drying and baking to set its shape. Alternatively, the woven Oxford cloth fabric layer may undergo antibacterial post-treatment, using either air spraying or electrostatic spraying, with the antibacterial agent's dry weight gain being 0.05%-2% of the fabric mass. After application, it may be treated with natural air drying or low-temperature drying processes. Alternatively, the woven Oxford cloth fabric layer undergoes a three-proof treatment. The three-proof additives are uniformly applied to the fabric surface through one of the following processes: spraying, foaming, or padding. After hot air drying and baking to cure into a film, the dry weight gain of the three-proof additives is controlled to be 20 g / m². 2 -100 g / m 2 .

10. The application of the woven Oxford cloth and polypropylene screw extrusion hot melt composite material according to any one of claims 1-4, characterized in that: The composite material is used to prepare protective armor or electrostatic protective canopy. The composite material is preheated by at least one of hot air, infrared, and roller methods. The preheating temperature is 40-120 ℃ and the traction speed is 0.5-1 m / min. The preheated composite material is oriented and folded by a heatable folding machine to obtain an electrostatic protective canopy. After cooling and shaping, it is integrated with stainless steel armor plates or aluminum alloy armor plates to obtain protective armor.

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