High-strength polycarbonate composite tube and preparation method thereof

Abstract

The invention provides a high-strength polycarbonate composite tube and a preparation method thereof, and relates to the technical field of polycarbonate composite tubes. The high-strength polycarbonate composite tube comprises three layers of gradient functional structures, namely an inner layer, a metal layer and an outer layer from inside to outside in sequence, the inner layer is prepared from the following raw materials in parts by mass: 50 to 60 parts of PC, 5 to 8 parts of MBS, 0.1 to 2 parts of silicone powder and 0.1 to 3 parts of glass fiber; the metal layer comprises the following raw materials in parts by mass: 35-40 parts of a copper wire gauze with a nickel-plated surface and 15-18 parts of a polyurethane / epoxy adhesive; the outer layer is prepared from the following raw materials in parts by mass: 45 to 55 parts of PC, 2 to 3 parts of UV absorbent and 0.5 to 1 part of antioxidant. The high-strength polycarbonate composite tube disclosed by the invention has the performances of high strength, excellent low-temperature toughness, good electromagnetic shielding performance, excellent weather resistance, long service life and the like, can meet the diversified requirements of modern engineering application, and has wide application prospects and important economic values.

Description

Technical Field

[0001] This invention relates to the field of polycarbonate composite pipe technology, and in particular to a high-strength polycarbonate composite pipe and its preparation method. Background Technology

[0002] Polycarbonate (PC) pipes are widely used in construction, electronics, and communications due to their excellent transparency, impact resistance, and good dimensional stability. However, traditional PC pipes still face several problems in practical use. First, pure PC material is prone to brittle fracture at low temperatures, limiting its application in cold regions. Second, PC material lacks electromagnetic shielding, making it difficult to meet the electromagnetic interference protection requirements of electronic equipment and communication systems. Furthermore, PC material is sensitive to ultraviolet light; long-term outdoor use can lead to photodegradation, resulting in yellowing, decreased mechanical properties, and severely impacting its service life.

[0003] While traditional galvanized steel pipes possess good mechanical strength and electromagnetic shielding properties, they suffer from drawbacks such as heavy weight, susceptibility to corrosion, and poor processing performance. Their salt spray tolerance is limited to less than 1000 hours, and their impact toughness significantly decreases at low temperatures. Some studies have attempted to improve performance by adding single toughening agents or fillers to the PC matrix, but these often compromise overall performance, failing to simultaneously meet requirements for mechanical strength, low-temperature toughness, electromagnetic shielding, and weather resistance. Particularly in extreme low-temperature environments (-40℃), existing PC pipes exhibit very low impact strength, failing to meet the demands of harsh operating conditions.

[0004] Furthermore, the interlayer bonding strength of existing composite pipes is generally low, making them prone to delamination failure under high loads or temperature cycling conditions. Poor interfacial compatibility between the metal layer and the polymer matrix, coupled with a lack of effective chemical bonding, results in insufficient peel strength. Simultaneously, the metal layer exhibits poor oxidation resistance, making it susceptible to corrosion after prolonged use, further reducing the reliability and service life of the composite pipe.

[0005] Therefore, there is an urgent need to develop a high-performance PC composite pipe that combines high strength, excellent low-temperature toughness, good electromagnetic shielding performance, excellent weather resistance, and long service life to meet the diversified needs of modern engineering applications. Summary of the Invention

[0006] In view of this, the present invention provides a high-strength polycarbonate composite pipe and its preparation method. Compared with traditional galvanized steel pipes, the composite pipe of the present invention achieves electromagnetic shielding and mechanical strength while reducing weight, improving corrosion resistance, and significantly improving overall performance. Compared with pure PC pipes, the composite pipe of the present invention has improved low-temperature impact strength, added electromagnetic shielding function, improved weather resistance, and extended service life, and has broad application prospects and significant economic value.

[0007] The first aspect of the present invention is to provide a high-strength polycarbonate composite pipe, which includes a three-layer gradient functional structure, consisting of an inner layer, a metal layer, and an outer layer from the inside out. The inner layer comprises the following raw materials in parts by weight: 50-60 parts PC, 5-8 parts MBS, 0.1-2 parts silicone powder, and 0.1-3 parts glass fiber; The metal layer comprises the following raw materials in parts by weight: 35-40 parts of nickel-plated copper wire mesh and 15-18 parts of polyurethane / epoxy adhesive. The outer layer comprises the following raw materials in parts by weight: 45-55 parts PC, 2-3 parts UV absorber, and 0.5-1 parts antioxidant.

[0008] Preferably, the PC has an Mw of 25,000-35,000 g / mol and a glass transition temperature Tg of 145℃-150℃.

[0009] Preferably, the MBS is a core-shell structured MBS rubber particle with a core layer of polybutadiene and a shell layer of polymethyl methacrylate, and a particle size of 0.1-0.3 μm; the silicone powder has a particle size of 1-5 μm. The combination of core-shell MBS and silicone powder significantly improves low-temperature impact resistance through the synergistic effect of energy absorption and microcrack passivation, ensuring that the pipe maintains good mechanical properties even at -40℃.

[0010] Preferably, the glass fiber has a diameter of 10-15 μm and a length of 3-6 mm.

[0011] Preferably, the copper wire mesh adopts a hexagonal honeycomb weave structure with a weave density of 8-12 meshes and a copper wire diameter of 0.15-0.25 mm; the nickel layer thickness of the surface plating is 5-10 μm, and the nickel content in the plating layer is ≥95%. This invention improves the thermal conductivity and electromagnetic shielding effectiveness of the composite pipe by plating the copper wire mesh with nickel. The introduction of the nickel layer also significantly improves the oxidation resistance and interlayer bonding strength of the copper wire.

[0012] Preferably, the UV absorber is a benzotriazole UV absorber, more preferably UV-531 and / or UV-327. The UV absorber converts ultraviolet energy into heat dissipation through an excited-state energy transfer mechanism, and in conjunction with antioxidants, further extends its service life.

[0013] Preferably, the antioxidant is a hindered phenolic antioxidant. More preferably, it is antioxidant 1010.

[0014] Preferably, the polyurethane / epoxy adhesive is a polyurethane / epoxy resin hybrid system with a mass ratio of 1:1-2. Through the synergistic reaction of urethane bonds and epoxy groups, the polyurethane / epoxy adhesive forms a dense chemical bond layer at the interface between the PC matrix and the metal layer, ensuring that the three-layer structure does not delaminate under high load conditions.

[0015] Preferably, the high-strength polycarbonate composite tube has an ellipticity ≤5% and a surface roughness Ra ≤1.6 μm.

[0016] The second aspect of this invention is to provide a method for preparing a high-strength polycarbonate composite pipe, specifically including the following steps: S1. Weigh the raw materials according to the proportions; S2. Using a three-layer co-extrusion die base, the nickel-plated copper wire mesh is preheated and composited during the co-extrusion process. S3. Use a twin-screw mixer for plasticizing treatment to reduce melt viscosity while maintaining the glass transition temperature of the material; S4. Rapid cooling and shaping yields a high-strength polycarbonate composite pipe.

[0017] Preferably, in step S2, the inner layer temperature of the three-layer co-extrusion die is 180℃-200℃, the metal layer temperature is 180℃, and the outer layer temperature is 190℃-210℃; the screw speed is 280-320 rpm, and the traction speed is 2-5 m / min; the preheating temperature is 180℃; and during the composite process, a contact pressure of 0.6-1.0 MPa is applied to the copper wire mesh, and the composite is carried out for 20-40 seconds.

[0018] Preferably, in step S3, the shear rate is 1600-2000 rpm, the mixing temperature is 180℃-200℃, and the mixing time is 5-15 min.

[0019] Preferably, in step S3, the cooling is a combination of atomized water cooling and air cooling, and the cooling rate is ≥50℃ / s.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention improves the tensile and flexural strength of composite pipes through a three-layer gradient functional structure, achieving higher strength while reducing weight and improving processability. Particularly noteworthy is the significant improvement in low-temperature impact performance. Through the synergistic toughening mechanism of MBS core-shell structured rubber particles and silicone powder, the material maintains good impact strength even at -40℃, ensuring the reliability and safety of the pipes in extremely cold environments.

[0021] This invention improves the shielding effectiveness of the composite pipe by incorporating a hexagonal honeycomb braided nickel-plated copper wire mesh in the intermediate layer, combined with a polyurethane / epoxy hybrid adhesive to form a chemically bonded layer. This effectively solves the electromagnetic interference problem in electronic equipment and communication systems. The introduction of the nickel layer not only improves thermal conductivity and electromagnetic shielding effectiveness but also significantly enhances the oxidation resistance of the copper wire, greatly extending the service life of the pipe in corrosive environments.

[0022] This invention effectively inhibits the photo-oxidative degradation of PC material through the synergistic effect of benzotriazole UV absorbers and hindered phenolic antioxidants in the outer layer, ensuring that the pipe can maintain good appearance and mechanical properties even after long-term outdoor use.

[0023] This invention utilizes an optimized three-layer co-extrusion process to precisely control temperature gradient, contact pressure, and residence time, ensuring that the three-layer structure does not delaminate under high load and temperature cycling conditions. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of the invention. In the following embodiments, all raw materials are commercially available.

[0025] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0026] Example 1 A high-strength polycarbonate composite pipe, with the following composition by weight: Inner layer: 60 parts PC, 8 parts MBS toughening agent, 2 parts silicone powder, 3 parts glass fiber; Metal layer: 40 parts nickel-plated copper wire mesh, 18 parts polyurethane / epoxy adhesive; Outer layer: 55 parts PC, 3 parts UV-531, 1 part antioxidant 1010; The components are as follows: PC has a molecular weight (Mw) of 30,000 g / mol and a glass transition temperature (Tg) of 147℃; MBS toughening agent has a core-shell structure, with a core layer of polybutadiene and a shell layer of polymethyl methacrylate, with a particle size of 0.2 μm; silicone powder has a particle size of 3 μm; glass fiber has a diameter of 12 μm and a length of 4.5 mm; nickel-plated copper wire mesh has a hexagonal honeycomb braided structure with a braiding density of 10 mesh, a copper wire diameter of 0.20 mm, a nickel layer thickness of 7.5 μm, and a nickel content in the coating of ≥95%; polyurethane / epoxy adhesive is a polyurethane / epoxy resin hybrid system with a mass ratio of 1:1.5; Preparation method: S1. Weigh the raw materials according to the proportions; S2. A three-layer co-extrusion die is used with temperature gradient control: inner layer 200℃, metal layer preheated to 180℃, outer layer 210℃, screw speed 320 rpm, and traction speed 3 m / min. After the copper wire mesh is hexagonally woven and chemically nickel-plated, it is preheated to 180℃ during co-extrusion, a contact pressure of 1.0 MPa is applied, and it is held for 30 s for lamination. S3. Plasticization treatment is carried out using a twin-screw mixer, with the shear rate controlled at 2000 rpm, the mixing temperature at 200℃, and the mixing time at 10 min. S4. A combination of atomized water cooling and air cooling is used to obtain a high-strength polycarbonate composite pipe with a water temperature of 20℃ and a cooling rate of 50℃ / s.

[0027] Comparative Example 1 Traditional galvanized steel pipe.

[0028] Comparative Example 2 The difference from Example 1 is that there is no metal layer.

[0029] Comparative Example 3 The difference from Example 1 is that the inner layer consists of 73 parts PC and 3 parts glass fiber.

[0030] Comparative Example 4 The difference from Example 1 is that the metal layer consists of 40 parts of unplated nickel-copper wire mesh and 18 parts of polyurethane / epoxy adhesive.

[0031] Comparative Example 5 The difference from Example 1 is that: outer layer: 55 parts of PC.

[0032] Comparative Example 6 The difference from Example 1 is that the contact pressure is 0.3 MPa, the residence time is 10 s, and the cooling rate is 20℃ / s.

[0033] The performance of the composite tubes obtained in each embodiment was tested using the same method. Sample specifications: outer diameter Φ110 mm, wall thickness 8 mm, length 1000 mm; test environment: temperature 23±2℃, relative humidity 50±5% (except for special tests); accelerated aging conditions: xenon lamp irradiation intensity 550 W / m 2 Blackboard temperature 65℃, humidity cycle: 120 min dry / 18 min spray. Some test reference standards are as follows: GB / T 1040, GB / T 9341, GB / T 1843, GB / T 1633, GB / T 12190, GB / T 1410, GB / T 10125, GB / T 11547, GB / T 16422, GB / T 7141, GB / T 2792, GB / T 1036, GB / T 2408.

[0034] The test results are as follows:

[0035] This invention significantly improves electromagnetic shielding performance by introducing a three-layer composite structure (Example 1 vs. Comparative Example 2); it greatly enhances the material's low-temperature impact strength at -40℃ by employing a synergistic toughening system of MBS and silicone powder (Example 1 vs. Comparative Example 3); it extends the salt spray test tolerance time and improves shielding effectiveness by using a nickel-plated copper wire mesh as the shielding layer (Example 1 vs. Comparative Example 4), balancing corrosion resistance and electromagnetic shielding performance; it significantly enhances the material's weather resistance by constructing a composite system of UV absorber and antioxidant (Example 1 vs. Comparative Example 5), improving strength retention after UV aging and extending service life; and it effectively enhances interlayer bonding and dimensional stability, improving peel strength and reducing ellipticity by optimizing process parameters (Example 1 vs. Comparative Example 6). Finally, compared with traditional materials (Example 1 vs. Comparative Example 1), the overall performance of the composite pipe of this invention is significantly improved.

[0036] Example 2 A high-strength polycarbonate composite pipe, with the following composition by weight: Inner layer: 50 parts PC, 5 parts MBS toughening agent, 0.1 parts silicone powder, 0.1 parts glass fiber; Metal layer: 35 parts nickel-plated copper wire mesh, 15 parts polyurethane / epoxy adhesive; Outer layer: 45 parts PC, 2 parts UV-327, 0.5 parts antioxidant 1010; Preparation method: S1. Weigh the raw materials according to the proportions; S2. A three-layer co-extrusion die is used with temperature gradient control: inner layer 180℃, metal layer preheated to 180℃, outer layer 190℃, screw speed 280 rpm, and traction speed 2 m / min. The copper wire mesh is hexagonally honeycomb woven (weaving density 8 mesh, copper wire diameter 0.15mm) and chemically nickel-plated (nickel layer thickness 5 μm). During the co-extrusion process, it is preheated to 180℃, a contact pressure of 0.6 MPa is applied, and it is held for 20 s for lamination. S3. Plasticization treatment is carried out using a twin-screw mixer, with the shear rate controlled at 1600 rpm, the mixing temperature at 180℃, and the mixing time at 5 min. S4. A combination of atomized water cooling and air cooling is used to obtain a high-strength polycarbonate composite pipe with a water temperature of 15℃ and a cooling rate of 50℃ / s.

[0037] Example 3 A high-strength polycarbonate composite pipe, with the following composition by weight: Inner layer: 55 parts PC, 6.5 parts MBS toughening agent, 1 part silicone powder, 1.5 parts glass fiber; Metallic layer: 37.5 parts nickel-plated copper wire mesh, 16.5 parts polyurethane / epoxy adhesive; Outer layer: 50 parts PC, 2.5 parts UV-531, 0.75 parts antioxidant 1010; Preparation method: S1. Weigh the raw materials according to the proportions; S2. A three-layer co-extrusion die is used with temperature gradient control: inner layer 190℃, metal layer preheated to 180℃, outer layer 200℃, screw speed 300 rpm, and traction speed 3.5 m / min. After the copper wire mesh is hexagonally honeycomb woven (weaving density 10 mesh, copper wire diameter 0.20 mm) and chemically nickel-plated (nickel layer thickness 7.5 μm), it is preheated to 180℃ during co-extrusion, a contact pressure of 0.8 MPa is applied, and it is held for 30 s for lamination. S3. Plasticization treatment is carried out using a twin-screw mixer, with the shear rate controlled at 1800 rpm, the mixing temperature at 190℃, and the mixing time at 7.5 min. S4. A combination of atomized water cooling and air cooling is used, with a water temperature of 18℃ and a cooling rate of 60℃ / s, to obtain a high-strength polycarbonate composite pipe.

[0038] Example 4 A high-strength polycarbonate composite pipe, with the following composition by weight: Inner layer: 52 parts PC, 7 parts MBS toughening agent, 0.5 parts silicone powder, 2 parts glass fiber; Metal layer: 38 parts nickel-plated copper wire mesh, 17 parts polyurethane / epoxy adhesive; Outer layer: 48 parts PC, 1.5 parts UV-531, 1 part UV-327, 0.8 parts antioxidant 1010; Preparation method: S1. Weigh the raw materials according to the proportions; S2. A three-layer co-extrusion die is used with temperature gradient control: inner layer 185℃, metal layer preheated to 180℃, outer layer 195℃, screw speed 290 rpm, and traction speed 2.5 m / min. The copper wire mesh is hexagonally honeycomb woven (weaving density 9 mesh, copper wire diameter 0.18 mm) and chemically nickel-plated (nickel layer thickness 6 μm). During the co-extrusion process, it is preheated to 180℃, a contact pressure of 0.7 MPa is applied, and it is held for 25 s for lamination. S3. Plasticization treatment is carried out using a twin-screw mixer, with the shear rate controlled at 1700 rpm, the mixing temperature at 185℃, and the mixing time at 6 min. S4. A combination of atomized water cooling and air cooling is used to obtain a high-strength polycarbonate composite pipe with a water temperature of 16℃ and a cooling rate of 55℃ / s.

[0039] Example 5 A high-strength polycarbonate composite pipe, with the following composition by weight: Inner layer: 58 parts PC, 7.5 parts MBS toughening agent, 1.5 parts silicone powder, 2.5 parts glass fiber; Metallic layer: 39 parts nickel-plated copper wire mesh, 17.5 parts polyurethane / epoxy adhesive; Outer layer: 53 parts PC, 2.8 parts UV-327, 0.9 parts antioxidant 1010; Preparation method: S1. Weigh the raw materials according to the proportions; S2. A three-layer co-extrusion die is used with temperature gradient control: inner layer 195℃, metal layer preheated to 180℃, outer layer 205℃, screw speed 310 rpm, and traction speed 4 m / min. The copper wire mesh is hexagonally honeycomb woven (weaving density 11 mesh, copper wire diameter 0.22mm) and chemically nickel-plated (nickel layer thickness 8 μm). During co-extrusion, it is preheated to 180℃, a contact pressure of 0.9 MPa is applied, and it is held for 35 s for lamination. S3. Plasticization treatment was carried out using a twin-screw mixer, with the shear rate controlled at 1900 rpm, the mixing temperature at 195℃, and the mixing time at 8.5 min. S4. A combination of atomized water cooling and air cooling is used to obtain a high-strength polycarbonate composite pipe with a water temperature of 19℃ and a cooling rate of 65℃ / s.

[0040] Example 6 A high-strength polycarbonate composite pipe, with the following composition by weight: Inner layer: 54 parts PC, 6 parts MBS toughening agent, 0.8 parts silicone powder, 1 part glass fiber; Metal layer: 36 parts nickel-plated copper wire mesh, 16 parts polyurethane / epoxy adhesive; Outer layer: 47 parts PC, 2.2 parts UV-531, 0.6 parts antioxidant 1010; Preparation method: S1. Weigh the raw materials according to the proportions; S2. A three-layer co-extrusion die is used with temperature gradient control: inner layer 188℃, metal layer preheated to 180℃, outer layer 198℃, screw speed 295 rpm, and traction speed 4.5 m / min. The copper wire mesh is hexagonally honeycomb woven (weaving density 12 mesh, copper wire diameter 0.25 mm) and chemically nickel-plated (nickel layer thickness 10 μm). During the co-extrusion process, it is preheated to 180℃, a contact pressure of 0.75 MPa is applied, and it is held for 28 s for lamination. S3. Plasticization treatment was carried out using a twin-screw mixer, with the shear rate controlled at 1750 rpm, the mixing temperature at 188℃, and the mixing time at 9 min. S4. A combination of atomized water cooling and air cooling is used to obtain a high-strength polycarbonate composite pipe with a water temperature of 17℃ and a cooling rate of 58℃ / s.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high-strength polycarbonate composite pipe, characterized by, The composite pipe comprises three layers of gradient functional structures, namely, an inner layer, a metal layer and an outer layer from inside to outside. The inner layer comprises the following raw materials in parts by mass: PC 50-60 parts, MBS 5-8 parts, silicone powder 0.1-2 parts, and glass fiber 0.1-3 parts. The metal layer comprises the following raw materials in parts by mass: copper wire mesh plated with nickel 35-40 parts, and polyurethane / epoxy adhesive 15-18 parts. The outer layer comprises the following raw materials in parts by mass: PC 45-55 parts, UV absorber 2-3 parts, and antioxidant 0.5-1 part.

2. A high-strength polycarbonate composite pipe according to claim 1, characterized in that, The PC has a Mw of 25,000-35,000 g / mol and a glass transition temperature Tg of 145-150℃.

3. A high-strength polycarbonate composite pipe according to claim 1, wherein The MBS is an MBS rubber particle with a core-shell structure, wherein the core layer is polybutadiene and the shell layer is polymethyl methacrylate, and the particle size is 0.1-0.3 μm.

4. The high-strength polycarbonate composite pipe according to claim 1, wherein The silicone powder has a particle size of 1-5 μm.

5. The high-strength polycarbonate composite pipe according to claim 1, wherein The copper wire mesh adopts a hexagonal honeycomb weaving structure, and has a weaving density of 8-12 meshes and a copper wire diameter of 0.15-0.25 mm.

6. A high-strength polycarbonate composite pipe according to claim 1, wherein The nickel layer of the copper wire mesh plated with nickel has a thickness of 5-10 μm, and the nickel content in the plating layer is ≥95%.

7. A high-strength polycarbonate composite pipe according to claim 1, wherein The UV absorber is a benzotriazole UV absorber.

8. A high-strength polycarbonate composite pipe according to claim 7, wherein The UV absorber is UV-531 and / or UV-327.

9. A high-strength polycarbonate composite pipe according to claim 7, wherein The high-strength polycarbonate composite pipe has an ellipticity of ≤5% and a surface roughness Ra of ≤1.6 μm.

10. The method of making a high-strength polycarbonate composite pipe according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: S1, proportionally weighing raw materials; S2, preheating and compounding the copper wire mesh plated with nickel in a co-extrusion process by using a three-layer co-extrusion die base; S3, using a double-screw mixing machine for plasticizing treatment to reduce the melt viscosity while maintaining the glass transition temperature of the material; S4, rapid cooling and shaping to obtain a high-strength polycarbonate composite pipe.

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