A weather-resistant fiberglass reinforced plastic (FRP) pipe material for above-ground use and its preparation method

Abstract

This invention relates to a weather-resistant fiberglass reinforced plastic (FRP) pipe material for above-ground applications and its preparation method, belonging to the field of composite material preparation technology. The FRP pipe material comprises: 100 parts unsaturated polyester resin, 1-5 parts curing agent, 0.5-3 parts accelerator, 20-30 parts glass fiber, 10-20 parts nano-sheet magnesium hydroxide, 0.12-0.45 parts antioxidant, and 5-15 parts UV stabilizer. The UV stabilizer is a porous spherical CeO2-SnO2. The addition of one-dimensional glass fiber, two-dimensional magnesium hydroxide, and porous spherical CeO2-SnO2 during the preparation of the FRP pipe significantly improves the material's mechanical properties. This FRP pipe material exhibits excellent performance in anti-aging and UV resistance, while its mechanical properties are significantly improved, providing a superior technical solution for FRP pipe materials used in above-ground environments.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, and relates to a fiberglass pipe material with excellent weather resistance for use in above-ground environments and its preparation method. It is applicable to fields such as building construction, power communication, and rail transportation, and can improve the UV aging resistance and mechanical properties of fiberglass pipes in open-air environments. Background Technology

[0002] Fiberglass reinforced plastic (FRP) pipes are widely used in engineering fields due to their excellent corrosion resistance, lightweight yet high strength, superior hydraulic properties, and good designability, especially in water treatment, chemical engineering, marine engineering, and power transmission, where they demonstrate unique performance advantages. However, when FRP pipes are used in open-air environments, prolonged exposure to solar ultraviolet radiation leads to photo-oxidative aging, resulting in surface chalking, resin degradation, and a significant decrease in mechanical properties, ultimately shortening the pipe's service life. To improve the weather resistance of FRP pipes, existing technologies typically employ the application of an anti-UV coating or the introduction of UV stabilizers during the pipe's manufacturing process. For example, CN112574655B introduces modified cellulose into the FRP coating to improve its mechanical properties and UV aging resistance. The cellulose surface contains numerous hydroxyl groups, and nano-sized iron oxide particles are electrostatically adsorbed onto the cellulose surface, forming a multi-layered, complex modified cellulose structure that enhances the UV resistance of the FRP pipe. CN103756549B describes a method for preparing a varnish by dispersing nano-silica powder and nano-alumina powder through ball milling with anhydrous ethanol and then mixing them with other components. This varnish is then applied to the surface of fiberglass to improve its UV resistance. However, in the above-mentioned prior art, the coating suffers from problems such as easy peeling and rapid failure. CN116512642B discloses the introduction of a UV-resistant agent composed of salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines, and hindered amines during the preparation of fiberglass pipes, but the UV-resistant agent has limited effectiveness.

[0003] Therefore, developing a fiberglass pipe material for ground use that combines long-lasting UV aging resistance with excellent mechanical properties is of great practical significance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art, solve the technical problems of poor weather resistance, easy coating failure, and limited UV protection of existing fiberglass pipe materials in open-air environments, and provide a weather-resistant fiberglass pipe material for ground use and its preparation method.

[0005] To achieve the above-mentioned objectives, the present invention provides a weather-resistant fiberglass pipe material for ground use, comprising the following components by weight: 100 parts unsaturated polyester resin, 1-5 parts curing agent, 0.5-3 parts accelerator, 20-30 parts glass fiber, 10-20 parts nano-sheet magnesium hydroxide, 0.12-0.45 parts antioxidant, and 5-15 parts UV stabilizer.

[0006] The UV stabilizer described in this invention is a porous spherical CeO2-SnO2 composite material. The specific preparation method of this material is as follows: Cerium salt, tin salt, and urea are dissolved in a mixed solvent composed of deionized water and anhydrous ethanol, wherein the volume ratio of deionized water to anhydrous ethanol is 1:1; then potassium chloride and sodium citrate are added, mixed evenly, and transferred to a high-pressure reactor for hydrothermal reaction at 160-190℃. After the reaction is completed, the material is centrifuged, washed, and dried to obtain the porous spherical CeO2-SnO2 material.

[0007] The cerium salts described in this invention are cerium nitrate, cerium sulfate, and cerium chloride.

[0008] The tin salts described in this invention are tin tetrachloride and tin nitrate.

[0009] The molar ratio of cerium salt to tin salt described in this invention is (1-4):1. The urea and metal ions (Ce³) described in this invention + +Sn 4+ The molar ratio of ) is (2-4):1.

[0010] The molar ratio of Sn salt, KCl, and sodium citrate described in this invention is 1:(0.1-0.5):(1-2).

[0011] The hydrothermal reaction time described in this invention is 12-24 hours.

[0012] The method for preparing nano-sheet magnesium hydroxide according to the present invention adopts the method disclosed in the prior art CN103601223B. Specifically, in an alkaline solution, potassium oxalate is used as a dispersant and calcined magnesium oxide at high temperature is used as a magnesium source. After the reaction is completed, the magnesium hydroxide is obtained by hydration reaction, followed by filtration, drying, and pulverization. The reaction temperature is 70-100℃ and the reaction time is 3-4h.

[0013] This invention also provides a method for preparing weather-resistant fiberglass pipe material for above-ground use, comprising the following steps: Step 1: According to the formula, mix the unsaturated polyester resin, accelerator, antioxidant and the prepared porous spherical CeO2-SnO2 anti-UV agent, and stir at high speed until uniform to obtain the resin mixture; Step 2: Add glass fiber and nano-flake magnesium hydroxide evenly to the resin mixture obtained in Step 1, and continue stirring until the fiber and filler are evenly dispersed. Then add curing agent and mix evenly to obtain the final mixture.

[0014] Step 3: Shape the final mixture obtained in Step 2 into a mold and cure it at room temperature or under heating conditions.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: First, the prepared porous spherical CeO2-SnO2 composite material is a highly efficient ultraviolet absorber. CeO2 itself has excellent ultraviolet shielding capabilities, while the combination of SnO2 and CeO2 introduces oxygen vacancies and interfacial defects, which can significantly enhance the absorption and scattering efficiency of ultraviolet light. Furthermore, the porous spherical structure greatly increases the specific surface area of ​​the material, allowing it to come into more complete contact with ultraviolet light. Moreover, the porous structure is less prone to migration and precipitation, achieving long-term resistance to ultraviolet aging.

[0016] Secondly, a multi-level synergistic reinforcement composite system of one-dimensional, two-dimensional, and three-dimensional layers was constructed. Glass fiber, as the traditional reinforcing skeleton, provides the main axial tensile strength. Magnesium hydroxide, with its sheet-like structure, not only acts as a flame retardant, but its two-dimensional sheet morphology also creates a "maze effect" in the resin matrix, effectively hindering crack propagation and improving the rigidity and impact resistance of the pipe. Porous spherical CeO2-SnO2 particles, as spherical particles, can be successfully distributed between magnesium hydroxide nanosheets and glass fibers, effectively filling the gaps and further enhancing mechanical properties. The three fillers of different dimensions form a synergistic effect in the resin matrix, significantly improving the overall mechanical properties of the fiberglass material.

[0017] Third, the introduction of magnesium hydroxide not only enhances the mechanical properties, but also endows the pipe material with good flame retardant and smoke suppression properties, making it more suitable for above-ground environments with high safety requirements. Attached Figure Description

[0018] Figure 1 The scanning electron microscope (SEM) image and nitrogen adsorption-desorption curve of the porous spherical CeO2-SnO2 material prepared for this invention show that it has a mesoporous spherical structure. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings.

[0020] Example 1: This embodiment relates to the preparation process of porous spherical CeO2-SnO2 UV stabilizer: 10 mmol Ce(NO3)3·6H2O and 5 mmol SnCl4·5H2O were dissolved in 60 mL of a mixed solvent consisting of deionized water and anhydrous ethanol in a 1:1 volume ratio. 30 mmol urea was added, and after stirring to dissolve, 2.5 mmol KCl and 10 mmol sodium citrate were added. Stirring continued for 30 minutes. The mixture was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 18 hours. After naturally cooling to room temperature, the product was centrifuged, washed three times with deionized water and anhydrous ethanol, and then vacuum-dried at 80 °C for 12 hours to obtain a white powder, which is the porous spherical CeO2-SnO2 material.

[0021] The fiberglass pipe material preparation process involved in this embodiment is as follows: (1) Weigh out 100 parts of unsaturated polyester resin, 2 parts of curing agent - methyl ethyl ketone peroxide, 1 part of accelerator - cobalt naphthenate, 25 parts of glass fiber, 15 parts of nano-sheet magnesium hydroxide, 0.2 parts of hindered phenolic antioxidant 1010, and 10 parts of porous spherical CeO2-SnO2. (2) Add unsaturated polyester resin, accelerator, antioxidant and CeO2-SnO2 powder to the high-speed mixer in sequence, and stir at 800 rpm for 20 minutes to ensure that the filler is evenly dispersed.

[0022] (3) Slowly add glass fiber and nano-sheet magnesium hydroxide to the above mixture, continue stirring for 30 minutes, and finally add curing agent and stir for 5 minutes until all components are mixed evenly to obtain a paste composite material.

[0023] (4) The paste-like composite material is shaped by weaving and winding pultrusion process and cured at 100℃ and 5MPa pressure for 30 minutes to obtain the final product.

[0024] Example 2: The preparation process of the porous spherical CeO2-SnO2 UV stabilizer involved in this embodiment is as follows: 10 mmol Ce(NO3)3·6H2O and 5 mmol SnCl4·5H2O were dissolved in 60 mL of a mixed solvent consisting of deionized water and anhydrous ethanol in a 1:1 volume ratio. 30 mmol urea was added, and after stirring to dissolve, 2.5 mmol KCl and 10 mmol sodium citrate were added. Stirring continued for 30 minutes. The mixture was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 190 °C for 12 hours. After naturally cooling to room temperature, the product was centrifuged, washed three times with deionized water and anhydrous ethanol, and then vacuum-dried at 80 °C for 12 hours to obtain a white powder, which is the porous spherical CeO2-SnO2 material.

[0025] The fiberglass pipe material preparation process involved in this embodiment is as follows: (1) Weigh 100 parts of unsaturated polyester resin, 2 parts of curing agent - methyl ethyl ketone peroxide, 1 part of accelerator - cobalt naphthenate, 25 parts of glass fiber, 14 parts of nano-sheet magnesium hydroxide, 0.2 parts of hindered phenolic antioxidant 1010, and 10 parts of porous spherical CeO2-SnO2. (2) Add unsaturated polyester resin, accelerator, antioxidant and CeO2-SnO2 powder to the high-speed mixer in sequence, and stir at 800 rpm for 20 minutes to ensure that the filler is evenly dispersed.

[0026] (3) Slowly add glass fiber and nano-sheet magnesium hydroxide to the above mixture, continue stirring for 30 minutes, then add curing agent and stir for 5 minutes until all components are mixed evenly to obtain a paste composite material.

[0027] (4) The paste-like composite material is shaped by weaving and winding pultrusion process and cured at 100℃ and 5MPa pressure for 30 minutes to obtain the final product.

[0028] Comparative Example 1: The difference between this and Example 1 is that CeO2-SnO2 was not added during the preparation of the fiberglass pipe.

[0029] Comparative Example 2: The difference between this and Example 1 is that no nano-sheet magnesium hydroxide was added during the preparation of the fiberglass pipe.

[0030] Comparative Example 3: Preparation of CeO2 UV stabilizer 10 mmol Ce(NO3)3·6H2O was dissolved in 60 mL of a mixed solvent consisting of deionized water and anhydrous ethanol in a 1:1 volume ratio. 30 mmol urea was added, and after stirring to dissolve, 2.5 mmol KCl and 10 mmol sodium citrate were added. Stirring continued for 30 minutes. The mixture was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 18 hours. After natural cooling to room temperature, the product was centrifuged, washed three times with deionized water and anhydrous ethanol, and then vacuum-dried at 80 °C for 12 hours to obtain the CeO2 material.

[0031] FRP pipe material preparation (1) Weigh out 100 parts of unsaturated polyester resin, 2 parts of curing agent - methyl ethyl ketone peroxide, 1 part of accelerator - cobalt naphthenate, 25 parts of glass fiber, 15 parts of nano-sheet magnesium hydroxide, 0.2 parts of hindered phenolic antioxidant 1010, and 10 parts of CeO2. (2) Add unsaturated polyester resin, accelerator, antioxidant and CeO2 powder in sequence to a high-speed mixer and stir at 800 rpm for 20 minutes to ensure that the filler is evenly dispersed.

[0032] (3) Slowly add glass fiber and nano-sheet magnesium hydroxide to the above mixture, continue stirring for 30 minutes, and finally add curing agent and stir for 5 minutes until all components are mixed evenly to obtain a paste composite material.

[0033] (4) The paste-like composite material is shaped by weaving and winding pultrusion process and cured at 100℃ and 5MPa pressure for 30 minutes to obtain the final product.

[0034] Comparative Example 4: Preparation of SnO2 UV stabilizer 5 mmol of SnCl₄·5H₂O was dissolved in 60 mL of a mixed solvent consisting of deionized water and anhydrous ethanol in a 1:1 volume ratio. 30 mmol of urea was added, and after stirring to dissolve, 2.5 mmol of KCl and 10 mmol of sodium citrate were added. Stirring continued for 30 minutes. The mixture was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 18 hours. After natural cooling to room temperature, the product was centrifuged, washed three times with deionized water and anhydrous ethanol, and then vacuum-dried at 80 °C for 12 hours to obtain the SnO₂ material.

[0035] FRP pipe material preparation (1) Weigh out 100 parts of unsaturated polyester resin, 2 parts of curing agent - methyl ethyl ketone peroxide, 1 part of accelerator - cobalt naphthenate, 25 parts of glass fiber, 15 parts of nano-sheet magnesium hydroxide, 0.2 parts of hindered phenolic antioxidant 1010, and 10 parts of SnO2. (2) Add unsaturated polyester resin, accelerator, antioxidant and SnO2 powder to the high-speed mixer in sequence, and stir at 800 rpm for 20 minutes to ensure that the filler is evenly dispersed.

[0036] (3) Slowly add glass fiber and nano-sheet magnesium hydroxide to the above mixture, continue stirring for 30 minutes, and finally add curing agent and stir for 5 minutes until all components are mixed evenly to obtain a paste composite material.

[0037] (4) The paste-like composite material is shaped by weaving and winding pultrusion process and cured at 100℃ and 5MPa pressure for 30 minutes to obtain the final product.

[0038] Performance testing and effect evaluation The fiberglass material samples prepared in Examples 1-2 and Comparative Examples 1-4 were subjected to the following performance tests, and the results are recorded in Table 1.

[0039] Test method: Accelerated UV aging test: According to GB / T 16422.3-2014 standard, a 1000-hour irradiation aging test was conducted using UVA lamps. The flexural strength and Barcol hardness before and after aging were tested according to GB / T 1449-2005 and GB / T 3854-2017 respectively, and the strength retention rate was calculated.

[0040] Flame retardant performance test: The limiting oxygen index (LOI) was tested in accordance with GB / T 2406.2-2009 standard.

[0041] Table 1: Performance test results of each embodiment and comparative example Results analysis:

[0042] As can be seen from Example 1 and Comparative Examples 1, 3, and 4, the fiberglass materials with the addition of the porous spherical CeO2-SnO2 of the present invention retain more than 90% of their bending strength after 1000 hours of ultraviolet aging. This is much higher than that of Comparative Example 1 without any UV stabilizer and Comparative Examples 3 and 4 with CeO2 and SnO2 as UV stabilizers alone. This indicates that the porous spherical CeO2-SnO2 provided by the present invention has extremely excellent UV shielding and absorption capabilities.

[0043] Comparing Example 1 and Comparative Example 1, it can be seen that the addition of porous spherical CeO2-SnO2 significantly improved the flexural strength and Barcol hardness of the material. Comparing Example 1 and Comparative Example 2, it can be seen that the mechanical properties of the material are significantly reduced without the two-dimensional nanosheet magnesium hydroxide.

[0044] The LOI values ​​of Examples 1-2 and Comparative Examples 1, 3, and 4 with added nanosheet magnesium hydroxide were significantly higher than those of Comparative Example 2 without added magnesium hydroxide, demonstrating that nanosheet magnesium hydroxide provides good flame retardant properties for the material.

Claims

1. A weather-resistant fiberglass reinforced plastic (FRP) pipe material for above-ground applications, characterized in that, It comprises the following raw materials, by weight: 100 parts unsaturated polyester resin, 1-5 parts curing agent, 0.5-3 parts accelerator, 20-30 parts glass fiber, 10-20 parts nano-sheet magnesium hydroxide, 0.12-0.45 parts antioxidant, and 5-15 parts UV stabilizer; wherein the UV stabilizer is a porous spherical CeO2-SnO2 composite material; the specific synthesis process of CeO2-SnO2 is as follows: Cerium salt, tin salt, and urea were dissolved in a mixed solvent of deionized water and anhydrous ethanol in a volume ratio of 1:

1. Potassium chloride and sodium citrate were then added, and the mixture was transferred to a high-pressure reactor for hydrothermal reaction at 160-190℃ to obtain the porous spherical CeO2-SnO2 composite material.

2. The weather-resistant fiberglass pipe material for above-ground use according to claim 1, characterized in that, The molar ratio of the cerium salt to the tin salt is (1-4):

1.

3. The weather-resistant fiberglass pipe material for above-ground use according to claim 1, characterized in that, The nanosheet magnesium hydroxide has a size of 300-800 nm.

4. The weather-resistant fiberglass pipe material for above-ground use according to claim 1, characterized in that, The antioxidant is at least one of hindered phenolic antioxidants or phosphite antioxidants.

5. The weather-resistant fiberglass pipe material for above-ground use according to claim 1, characterized in that, The molar ratio of urea to the sum of cerium and tin metal ions is (2-4):

1.

6. The weather-resistant fiberglass pipe material for above-ground use according to claim 1, characterized in that, The molar ratio of tin salt, KCl, and sodium citrate is 1:(0.1-0.5):(1-2).

7. The weather-resistant fiberglass pipe material for above-ground use according to claim 1, characterized in that, The hydrothermal reaction time is 12-24 hours.

8. A method for preparing a weather-resistant fiberglass reinforced plastic (FRP) pipe for above-ground use as described in any one of claims 1-7, characterized in that, Includes the following steps: Step S1: Mix unsaturated polyester resin, accelerator, antioxidant and porous spherical CeO2-SnO2 UV stabilizer, stir evenly to obtain resin mixture; Step S2: Add glass fiber and nano-sheet magnesium hydroxide to the resin mixture obtained in step S1, continue stirring until evenly dispersed, and finally add curing agent. After mixing, the final mixture is obtained. Step S3: The final mixture obtained in step S2 is molded into pipe material through a molding process and then cured.

9. A weather-resistant fiberglass pipe for above-ground use, characterized in that, It is prepared from the fiberglass pipe material according to any one of claims 1-7 or the preparation method according to claim 8.

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