Basalt fiber glass fiber reinforced plastic insulation arm and preparation process thereof

Abstract

The invention relates to the technical field of composite material engineering, and discloses a basalt fiber glass fiber reinforced plastic insulating arm and a preparation process thereof, and an arm body of an insulating plate is prepared by pultrusion and subsequent machining of the following components: 50-75 parts by mass of basalt fiber or fabric thereof; 25-50 parts by mass of an epoxy resin system; the flame retardant comprises 0.5-2 parts by mass of a coupling agent and 1-5 parts by mass of a flame retardant. The arm body is a square tubular object, one end of the arm body is provided with a diagonal plane, five first round through holes distributed in a Z shape are formed in one side wall, close to one end of the diagonal plane, of the arm body, and four second round through holes distributed in a square shape are formed in one side wall of the other end of the arm body. A reinforced framework is constructed by basalt fibers, an epoxy resin matrix is combined, and a pultrusion technology is adopted. The finished insulation arm not only shows the end part bearing capacity of about 1 ton and the high insulation level of 200 kilovolts, but also has the characteristics of excellent chemical corrosion resistance and light weight.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material engineering, in particular to a basalt fiberglass reinforced plastic insulation arm and a preparation process thereof. Background Art

[0002] Fiber-reinforced composite materials, thanks to their lightweight, high-strength, excellent electrical insulation, chemical resistance, and designability, are finding increasing application in power systems, rail transit, new energy equipment, and engineering machinery. In particular, pultrusion, with its high production efficiency, relatively manageable costs, and ability to continuously produce uniform cross-section profiles, has become a mainstream manufacturing technology for these long, composite components, particularly in the manufacture of insulating operating rods, insulator core rods for high-voltage lines, structural support arms, and various other key components that require both load-bearing and insulation capabilities.

[0003] However, as practical application requirements continue to escalate, existing composite insulation arms and similar structural components are gradually revealing inherent limitations. Regarding material system selection, a large number of products currently utilize E-glass fiber as the primary reinforcement, combined with a general-purpose resin matrix. While this combination offers a lower cost, its mechanical performance ceiling is significant, making it difficult to meet the demanding requirements of certain high-end equipment for both extreme lightweighting and high load-bearing capacity. E-glass fiber itself has relatively limited resistance to high temperatures and chemical media (particularly alkaline environments), which directly restricts the long-term service stability and lifespan of its products in high-temperature operating conditions or complex chemical environments.

[0004] In summary, the fiber-reinforced composite insulation arms and similar structural parts in the existing technology still have many areas that need to be improved in terms of further improvement of comprehensive mechanical properties, strengthening and stabilizing interface bonding, precise shaping of complex structural features to adapt to advanced assembly requirements, and comprehensive enhancement of safety protection (such as flame retardancy) and environmental tolerance. It is difficult to fully meet the comprehensive requirements of modern engineering applications for high performance, high reliability, high integration and long life. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a basalt fiber glass fiber reinforced plastic insulation arm and its preparation process, which solves the problems existing in the existing fiber reinforced composite insulation arm in terms of comprehensive mechanical properties, precision structure adaptability, flame retardant safety and long-term service durability.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a basalt fiberglass reinforced plastic insulation arm, wherein the arm body of the insulation arm is made of the following components through pultrusion and subsequent mechanical processing: Reinforcement material: basalt fiber or its fabric, 50-75 parts by mass; Matrix material: epoxy resin system, 25-50 parts by mass; Auxiliary components: 0.5-2 parts by mass of coupling agent and 1-5 parts by mass of flame retardant; In addition, the arm body is a square tubular object, and one end of the arm body has a beveled surface. Five circular through holes arranged in a Z shape are opened on one side wall of the arm body near the end of the beveled surface, and four circular through holes arranged in a square shape are opened on one side wall of the other end of the arm body.

[0007] Preferably, the basalt fiber is a continuous fiber made from natural volcanic extrusive rock, which is melted at a temperature of 1450° C. to 1550° C. and drawn through a platinum-rhodium alloy drawing plate.

[0008] Preferably, the surface of the reinforcing material basalt fiber is treated with a silane coupling agent.

[0009] Preferably, the flame retardant is a compound of aluminum hydroxide and microencapsulated red phosphorus.

[0010] Preferably, the epoxy resin system comprises bisphenol A epoxy resin, an anhydride curing agent and an imidazole accelerator.

[0011] A preparation process of a basalt fiberglass reinforced plastic insulation arm comprises the following steps: S1. Raw material preparation: preparing basalt fiber or its fabric as a reinforcing material, and an epoxy resin matrix mixture containing an epoxy resin, a curing agent, an accelerator, and a flame retardant; S2 pultrusion: After the basalt fiber or its fabric is impregnated with the epoxy resin matrix mixture, it is pultruded and cured through a heated molding die having a square inner cavity to form a continuous square tubular profile; S3 cutting: the solidified square tubular profile is cut to a predetermined length to obtain a semi-finished insulating arm; S4. Subsequent machining: machining the semi-finished insulating arm product to form the beveled surface, the five circular through holes arranged in a Z-shape, and the four circular through holes arranged in a square shape.

[0012] Preferably, the basalt fiber or its fabric used as the reinforcing material in step S1 is pre-surface treated with a silane coupling agent.

[0013] Preferably, the curing temperature of the heating molding die in step S2 is in the range of 150°C to 220°C.

[0014] Preferably, the subsequent machining in step S3 includes: using a CNC machine tool to cut one end of the semi-finished insulating arm to form a bevel surface, and precisely machining the side wall thereof to form the Z-shaped circular through holes and the square-shaped circular through holes.

[0015] The present invention provides a basalt fiberglass reinforced plastic insulation arm and its preparation process, which has the following beneficial effects: 1. This invention utilizes basalt fiber as a reinforcement framework, combined with an epoxy resin matrix, and pultrusion technology. The finished insulating arm not only exhibits an end-load bearing capacity of approximately 1 ton and a high insulation rating of 200 kilovolts, but also offers excellent chemical resistance and lightweight properties. Compared to existing solutions that partially utilize glass fiber, this invention overcomes the latter's shortcomings in high-temperature resistance, oxidation resistance, and process stability.

[0016] 2. The core of this manufacturing process lies in achieving the required physical and chemical properties of the product through continuous pultrusion, while maintaining a constant product cross-sectional dimension, combined with the innovative application of basalt fiber, a natural mineral-based material, to replace imported products. This integration significantly improves production efficiency, ensures highly consistent product quality, and effectively controls manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A perspective view of the present invention; Figure 2 This is a structural schematic diagram of the insulating arm in the present invention from another perspective.

[0018] Among them, 1. arm body; 2. oblique section; 3. through hole 1; 4. through hole 2. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the specification of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] Please see the attached Figure 1 -Attached Figure 2 The embodiment of the present invention provides a basalt fiberglass reinforced plastic insulation arm, wherein the arm body 1 of the insulation arm is made of the following components through pultrusion and subsequent machining: Reinforcement material: basalt fiber or its fabric, 50-75 parts by mass; Matrix material: epoxy resin system, 25-50 parts by mass; Auxiliary components: 0.5-2 parts by mass of coupling agent and 1-5 parts by mass of flame retardant; In addition, the arm body 1 is a square tubular object, and has a beveled surface 2 at one end of the arm body 1. Five circular through holes 3 arranged in a Z shape are opened on one side wall of the arm body 1 near the end of the beveled surface 2, and four circular through holes 4 arranged in a square shape are opened on one side wall of the other end of the arm body 1.

[0021] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below. It should be noted that the following examples are only a few specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0022] A preparation process of a basalt fiberglass reinforced plastic insulation arm comprises the following steps: S1. Raw material preparation: preparing basalt fiber or its fabric as a reinforcing material, and an epoxy resin matrix mixture containing an epoxy resin, a curing agent, an accelerator, and a flame retardant; S2 pultrusion: After the basalt fiber or its fabric is impregnated with the epoxy resin matrix mixture, it is pultruded and cured through a heated molding die having a square inner cavity to form a continuous square tubular profile; S3 cutting: the solidified square tubular profile is cut to a predetermined length to obtain a semi-finished insulating arm; S4. Subsequent machining: machining the semi-finished insulating arm product to form the beveled surface, the five circular through holes arranged in a Z-shape, and the four circular through holes arranged in a square shape.

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, detailed embodiments will be provided below to illustrate the present invention in more detail.

[0024] Example 1: This embodiment aims to prepare a basalt fiberglass reinforced plastic insulation arm with balanced comprehensive performance.

[0025] Raw material composition (unit: parts by mass): Basalt fiber (continuous roving, surface treated): 62.5 parts by mass; Epoxy resin system (total): 37.5 parts by mass, its internal composition is: Bisphenol A epoxy resin (epoxy equivalent weight 180-190 g / eq): 19.623 parts by mass; Methyltetrahydrophthalic anhydride (curing agent): 17.661 parts by mass (90% of the mass of the epoxy resin); 2-Ethyl-4-methylimidazole (accelerator): 0.216 parts by mass (1.1% of the epoxy resin mass); Silane coupling agent (KH-560, used for fiber pretreatment and as an independently added auxiliary component): 1.25 parts by mass; Flame retardant compound (total): 3.0 parts by mass (8% of the total mass of the epoxy resin system), its internal composition is: Aluminum hydroxide (average particle size 5 μm): 2.25 parts by mass; Microencapsulated red phosphorus (MCP): 0.75 parts by mass; Silicon carbide micropowder (wear-resistant filler, average particle size 80 nm): 0.540 parts by mass (2.75% of the mass of epoxy resin); Hindered amine light stabilizer (HALS 770, anti-UV aging agent): 0.108 parts by mass (0.55% of the epoxy resin mass); Zinc stearate (internal mold release agent): 0.245 parts by mass (1.25% of the epoxy resin mass).

[0026] Preparation steps and process parameters: (a) Basalt Fiber Production and Pretreatment: Natural volcanic extrusive rock is crushed and placed in a furnace, where it is melted at 1500°C. The melt flows through a platinum-rhodium alloy drawing plate and is drawn into continuous basalt fiber roving. The resulting roving is then immersed in a 1.0% (mass concentration) ethanol solution of KH-560 silane coupling agent for 30 minutes, then dried in an 80°C oven for 2 hours before use.

[0027] (b) Careful Preparation of the Epoxy Resin Matrix Mixture: Place the measured amount of bisphenol A epoxy resin in a stirred kettle and preheat to approximately 55°C. Add zinc stearate, hindered amine light stabilizer, silicon carbide micropowder, and a premixed composite of aluminum hydroxide and microencapsulated red phosphorus flame retardant in sequence, stirring under moderate shear until all components are evenly dispersed. Once the mixture temperature drops below 40°C, add methyltetrahydrophthalic anhydride and 2-ethyl-4-methylimidazole. Continue stirring to ensure that all materials are evenly mixed and free of bubbles, forming the resin matrix impregnation material to be used. The remaining silane coupling agent is added to the resin mixture at this step.

[0028] (c) Implementation of the pultrusion process: The pre-treated and dried basalt fiber roving is drawn out from the creel in an orderly manner and evenly arranged through a tension control and guide combing device. The fiber bundle smoothly passes through the impregnation tank, which contains the resin matrix mixture prepared in step (b), to ensure that the fiber is completely impregnated. The impregnated fiber bundle passes through a pre-forming die to remove excess resin and initially shape it into a square tubular profile. Subsequently, the material is introduced into a heated metal forming die with a square inner cavity. The die temperature is set to a three-stage control: 160°C in the inlet zone, 180°C in the middle zone, and 200°C in the outlet zone. Under the steady pulling force of the traction device (for example, 0.5 m / min), the material is cured in the die to form a continuous square tubular profile.

[0029] (d) Cutting and Fine Machining: The solidified square tubular profile is removed from the mold and, after appropriate cooling via air or water cooling, accurately cut by automated cutting equipment to the desired final length (e.g., 2 meters), resulting in a semi-finished insulating arm. A precision CNC angle saw is used to create a chamfered surface at a specific angle according to the design drawings on one end of the semi-finished product. A five-axis CNC drilling and milling center then locates and drills five circular holes (e.g., 10 mm in diameter) along a Z-shaped trajectory on the tube wall near the chamfered surface. Four circular holes (e.g., 12 mm in diameter) are also CNC-machined on the corresponding sidewall at the other end of the insulating arm, arranged in a square pattern.

[0030] The basalt fiberglass reinforced plastic insulation arm produced in this embodiment achieves both end-load bearing capacity and insulation withstand voltage ratings that meet design expectations. The fiber-resin interface is well bonded, resulting in a dense overall structure. Its unique geometric structure, achieved through precision machining, fully meets the installation and use requirements under specific working conditions. Compared to traditional fiberglass products, this offers improvements in durability, process stability, and adaptability to complex structures, effectively addressing the demand for higher-performance insulating structural components in the prior art.

[0031] Example 2 (Using the lower limit of the technical solution parameters) This embodiment explores the basic performance and molding feasibility of the insulating arm when the material composition and process parameters take lower values.

[0032] Raw material composition (unit: parts by mass): Basalt fiber (continuous roving, surface treated): 50.0; Epoxy resin system (total): 25.0, its internal composition is: Bisphenol A epoxy resin: 14.689; Methylhexahydrophthalic anhydride (curing agent): 10.282 (70% of the mass of epoxy resin); N,N-dimethylbenzylamine (accelerator): 0.029 (0.2% of the mass of epoxy resin); Silane coupling agent (A-174, used for fiber pretreatment and as an independently added auxiliary component): 0.5; Flame retardant compound (total): 1.25 (5% of the total weight of the epoxy resin system), its internal composition is: Aluminum hydroxide: 0.833; Microencapsulated red phosphorus: 0.417; Silica powder (wear-resistant filler, average particle size 100 nm): 0.073 (0.5% of the mass of epoxy resin); Ultraviolet absorber (UV-P, anti-ultraviolet aging agent): 0.015 (0.1% of the mass of epoxy resin); Calcium stearate (internal release agent): 0.073 (0.5% of the mass of epoxy resin).

[0033] Preparation steps and process parameters: (a) Basalt Fiber Preparation and Pretreatment: Natural basalt ore is crushed and screened, then melted and drawn at 1450°C to produce continuous fibers. The fiber bundles are immersed in a 0.5% (mass concentration) aqueous solution of A-174 silane coupling agent (containing a small amount of acetic acid to adjust the pH) for 20 minutes and then dried at 70°C.

[0034] (b) Preparation of the epoxy resin matrix mixture: Bisphenol A epoxy resin is first mixed with calcium stearate, a UV absorber, silica powder, and a flame retardant compound. Once the mixture is homogenized, methylhexahydrophthalic anhydride and N,N-dimethylbenzylamine are added, stirring gently to avoid introducing excessive bubbles. The remaining silane coupling agent is also added at this stage.

[0035] (c) Pultrusion Process: The treated basalt fiber roving is guided into a dipping tank, where it is fully exposed to the resin mixture. A preform is then applied to the preform die, where excess resin is removed. The material then enters a heated, square-shaped mold. The curing temperature is set at a low, single temperature, such as 150°C. The pulling speed is then reduced to, for example, 0.3 m / min, to ensure adequate curing at this temperature.

[0036] (d) Cutting and Subsequent Processing: After solidification, the profile is continuously drawn out and then cut into segments as needed after cooling. Subsequent bevel cutting and the processing of Z-shaped and square-shaped holes are all performed using CNC equipment to ensure dimensional accuracy.

[0037] Despite employing a relatively low parameter configuration, the insulating arm produced in this embodiment still possesses basic structural integrity and insulation properties. The introduction of basalt fiber enhances its strength and environmental resistance compared to some traditional non-metallic materials. The resulting complex geometric features demonstrate the feasibility of this process route for specific structural requirements. This solution offers a potential option for cost-sensitive applications while partially overcoming the specific performance limitations of conventional materials.

[0038] Example 3 This embodiment aims to prepare a basalt fiberglass reinforced plastic insulation arm with extreme performance, and the upper limit values of various parameters are adopted to achieve the best effect.

[0039] Raw material composition (unit: parts by mass): Basalt fiber (high strength, surface treated): 75.0; Epoxy resin system (total): 50.0, its internal composition is: High temperature resistant bisphenol A epoxy resin: 23.585; Liquid anhydride curing agent (MHHPA): 25.944 (110% of the mass of epoxy resin); 2,4,6-Tris(dimethylaminomethyl)phenol (accelerator DMP-30): 0.472 (2.0% of the epoxy resin mass); Functional silane coupling agents (such as epoxy silane, used for fiber pretreatment and as independently added auxiliary components): 2.0; Flame retardant compound (total): 5.0 (accounting for 10% of the total mass of the epoxy resin system, ensuring it is within the 15% range), its internal composition is: Ultrafine aluminum hydroxide: 4.0; High-efficiency microencapsulated red phosphorus: 1.0; Nano silicon carbide (reinforced wear-resistant filler): 1.179 (5.0% of the mass of epoxy resin); Composite hindered amine light stabilizer (anti-UV aging agent): 0.236 (1.0% of the epoxy resin mass); Carnauba wax (high-efficiency internal release agent): 0.472 (2.0% of the mass of epoxy resin).

[0040] Preparation steps and process parameters: (a) Basalt Fiber Production and Pretreatment: High-quality basalt is melted at 1550°C and drawn through a precision platinum-rhodium alloy bushing to produce high-strength basalt fiber. The fiber is then passed under tension through a special solvent system containing 1.5% (mass concentration) of a functional silane coupling agent for in-line coating. The fiber then enters a high-temperature rapid drying unit.

[0041] (b) Preparation of the High-Performance Epoxy Resin Matrix Mixture: Heat-resistant bisphenol A epoxy resin is vigorously dispersed and mixed with carnauba wax, a composite hindered amine light stabilizer, nano-silicon carbide, and a specially formulated flame retardant compound in a planetary mixer. After cooling, a liquid anhydride curing agent and DMP-30 accelerator are added. After vacuum degassing, the mixture is stirred until uniform. The remaining silane coupling agent is added to form a high-solids, low-viscosity impregnating resin.

[0042] (c) Pultrusion Process: Large quantities of optimally pretreated basalt fiber bundles are introduced into the impregnation system under precise tension control, ensuring that the interstices between the fibers are fully filled with high-performance resin. An optimized preforming zone further increases the fiber content and precisely controls the cross-section. The material then enters a long-stroke, multi-temperature-zone mold with a temperature gradient set between 170°C and 190°C, 210°C, and 220°C. High pull-off speeds, such as 0.8 m / min, ensure efficient production.

[0043] (d) Cutting and Precision Hole Forming: The highly rigid square tubular profile is precisely segmented by a tracking cutting system at the end of pultrusion. The end bevels are formed using laser cutting or high-precision grinding. For Z-shaped holes and square-patterned holes, high-power laser drilling technology is used to ensure smooth, burr-free holes with high dimensional consistency.

[0044] The basalt fiberglass insulation arm produced in this embodiment exhibits exceptional mechanical strength and excellent electrical insulation properties. These superior properties are the result of a high fiber content, an optimized resin system, and sophisticated interface treatment. The product also exhibits significant improvements in high-temperature resistance, corrosion resistance, and aging resistance, far surpassing those of conventional fiberglass products. Its complex geometric configuration, achieved through advanced processing techniques, demonstrates that the present invention is capable of producing high-end components that meet the demands of demanding industrial applications, effectively addressing the shortcomings of existing technologies in the supply of high-performance, high-reliability insulation components.

[0045] To further highlight the significant advantages and creative improvements of the present invention's technical solution over existing technologies or certain alternatives, several comparative examples are provided below. These comparative examples simulate common material selection, structural design, or process methods in the prior art. Direct and objective performance comparisons between the embodiments and these comparative examples are conducted in subsequent testing experiments.

[0046] Comparative Example D1: Using ordinary glass fiber instead of basalt fiber This comparative example is intended to illustrate the criticality of selecting basalt fiber as the reinforcing material in the present invention.

[0047] The main difference from Example 1 is that the basalt fiber reinforcement is replaced with an equal amount of E-glass fiber roving. This will not fully demonstrate the unique properties of basalt fiber (such as heat resistance, corrosion resistance, and mechanical properties). The remaining components, proportions, and subsequent processing characteristics remain consistent with those of Example 1.

[0048] Preparation steps and process parameters: (a) Reinforcement Material Preparation: Commercially available E-glass fiber roving was selected. No special melt drawing step was performed. If necessary, the roving could be impregnated with a conventional silane coupling agent (e.g., KH-560, the same type as in Example 1). The treatment concentration and drying conditions were similar to those for the basalt fiber pretreatment in Example 1.

[0049] (b) Preparation of the epoxy resin matrix mixture: This step is identical to that of Example 1. Bisphenol A epoxy resin, methyltetrahydrophthalic anhydride curing agent, 2-ethyl-4-methylimidazole accelerator, and the flame retardant, wear-resistant filler, anti-ultraviolet aging agent, and internal release agent specified in Example 1 are used. The amounts of each component used are the same as those in Example 1.

[0050] (c) Implementation of the pultrusion process: The E-glass fiber roving was drawn from the creel, passed through a resin impregnation tank (containing the resin matrix mixture prepared in step (b)), and subsequently preformed, entered a heated metal forming mold with a square inner cavity (temperature control was the same as in Example 1: 160°C to 180°C to 200°C), and then pulled and solidified. The operating conditions were all consistent with those of Example 1.

[0051] (d) Cutting and Fine Machining: After curing, the glass fiber reinforced square tubular profile is similarly processed by cutting, end beveling, and forming Z-shaped holes and square-shaped holes. The processing equipment and parameters are kept consistent with those in Example 1.

[0052] Comparative Example D2: Simplified preparation process, lacking specific mechanical finishing steps This comparative example is intended to highlight the importance of the present invention in imparting specific structural features to the insulating arm through subsequent precision machining.

[0053] The main difference from Example 1 is that the same raw material components and proportions (basalt fiber, epoxy resin system, auxiliary components, etc.) are used as in Example 1. The pultrusion process is also essentially the same, resulting in a square tubular profile. The difference lies in the omission of the subsequent complex mechanical finishing steps of Example 1: namely, the end beveling is omitted, and the five circular through-holes arranged in a Z pattern and the four circular through-holes arranged in a square pattern are not provided. The final product is a simple basalt fiber-reinforced square tube with flat ends.

[0054] Preparation steps and process parameters: (a) Basalt fiber acquisition and pretreatment: exactly the same as in Example 1.

[0055] (b) Careful preparation of epoxy resin matrix mixture: exactly the same as in Example 1.

[0056] (c) Implementation of the pultrusion process: The same as in Example 1 was performed to obtain a continuous basalt fiber reinforced square tubular profile.

[0057] (d) Cutting: After the solidified square tubular profile emerges from the mold, it is precisely cut into pre-set lengths (e.g., 2 meters) by automated cutting equipment. This cutting process creates the final product, without any further end-face processing or hole drilling.

[0058] Comparative Example D3: Omitting the key coupling agent treatment or addition This comparative example is used to demonstrate the contribution of the coupling agent in the present invention to improving interface bonding and enhancing overall performance.

[0059] The main differences from Example 1 are: the reinforcing material is still basalt fiber, and the matrix resin system and other auxiliary components (except the coupling agent) are the same as in Example 1. The key differences are: (1) the basalt fiber is not pretreated with a silane coupling agent (KH-560); and (2) the 0.75 parts of silane coupling agent added in Example 1 is not added during the preparation of the resin matrix mixture. In other words, the use of the coupling agent is completely omitted.

[0060] Preparation steps and process parameters: (a) Basalt Fiber Acquisition: Natural basalt fiber roving was obtained in the same manner as in Example 1, but without any surface impregnation or coating treatment with a silane coupling agent.

[0061] (b) Preparation of the Epoxy Resin Matrix Mixture: This step is similar to Example 1, except that the silane coupling agent KH-560 is omitted. The types and amounts of the remaining components, such as the bisphenol A epoxy resin, curing agent, accelerator, flame retardant, and wear-resistant filler, are the same as in Example 1.

[0062] (c) Pultrusion Process: Basalt fiber rovings not treated with a coupling agent were directly impregnated, preformed, and then cured in a mold. Other process parameters (mold temperature, pulling speed, etc.) were kept consistent with those in Example 1.

[0063] (d) Cutting and fine processing: exactly the same as in Example 1, including end face beveling and processing of specific holes.

[0064] Comparative Example D4: Using different flame retardant systems or not adding flame retardant This comparative example is intended to illustrate the positive impact of the specific compound flame retardant system selected in the present invention on the safety performance of the product.

[0065] The main differences from Example 1 are: the core reinforcement material (basalt fiber), matrix resin (epoxy resin system), and coupling agent are all the same as in Example 1. The difference lies in the type and method of adding the flame retardant: (1) no flame retardant is added at all; or (2) it is replaced with a single flame retardant that may be less effective or have other disadvantages, such as adding only ordinary alumina trihydrate of the same mass without using microencapsulated red phosphorus for compounding. This example takes the case of no flame retardant being added at all.

[0066] Preparation steps and process parameters: (a) Basalt fiber acquisition and pretreatment: exactly the same as in Example 1.

[0067] (b) Preparation of the Epoxy Resin Matrix Mixture: This step is similar to Example 1, except that the flame retardant composite of aluminum hydroxide and microencapsulated red phosphorus is omitted. The types and amounts of the remaining components, such as the bisphenol A epoxy resin, curing agent, accelerator, and coupling agent, are the same as in Example 1.

[0068] (c) Implementation of the pultrusion process: After impregnating the basalt fiber roving with the resin mixture without flame retardant, pultrusion was performed. The remaining process parameters were kept consistent with those in Example 1.

[0069] (d) Cutting and fine processing: exactly the same as in Example 1.

[0070] Comparative Example D5: Using a different resin matrix (such as unsaturated polyester resin) This comparative example is used to demonstrate the superiority of the present invention in selecting an epoxy resin system as the matrix material.

[0071] The main differences from Example 1 are: the reinforcing material remains basalt fiber, and the coupling agent pretreatment is the same as in Example 1. Auxiliary components such as flame retardants and fillers are also maintained as much as possible (if they are compatible with the new resin system). The core difference is that the epoxy resin system (bisphenol A epoxy resin, anhydride curing agent, and imidazole accelerator) in Example 1 is replaced with an equal amount of unsaturated polyester resin (UPR) system (for example, a general-purpose phthalate-based unsaturated polyester resin, combined with the appropriate methyl ethyl ketone peroxide initiator and cobalt salt accelerator).

[0072] Preparation steps and process parameters: (a) Obtaining and pretreatment of basalt fiber: Exactly the same as in Example 1, the basalt fiber was pretreated with KH-560 silane coupling agent.

[0073] (b) Preparation of the unsaturated polyester resin matrix mixture: Weigh the specified amount of unsaturated polyester resin. Based on the resin manufacturer's recommendations and experimental conditions, add an appropriate amount of methyl ethyl ketone peroxide (MEKP) as an initiator and an appropriate amount of cobalt naphthenate solution as an accelerator. For comparison with other auxiliary components, try adding the flame retardant compound, wear-resistant filler, UV inhibitor, and internal release agent from Example 1 to this polyester system in the original proportions. However, be mindful of their compatibility with the polyester resin and their impact on the curing process.

[0074] (c) Pultrusion Process: The pretreated basalt fiber roving is impregnated with the unsaturated polyester resin mixture prepared in step (b). Because the curing mechanism and viscosity characteristics of polyester resin differ from those of epoxy resin, the pultrusion die temperature (possibly lower, such as 80-150°C, or adjusted based on the polyester system used), pulling speed, and curing time need to be adjusted accordingly to the properties of the unsaturated polyester resin to achieve a profile with good appearance.

[0075] (d) Cutting and fine processing: After the unsaturated polyester resin-based basalt fiber reinforced profiles are cured, they are also processed by cutting, end beveling, Z-shaped holes and square arrangement holes.

[0076] To objectively and quantitatively verify the claimed benefits of the present invention's technical solutions, including comprehensive improvements in mechanical load-bearing capacity, environmental aging resistance, structural assembly adaptability, and safety and protection features, this section will detail a series of carefully designed testing experiments. These experiments will be conducted strictly in accordance with established standards or scientific methods, systematically testing and comparing key performance indicators of the present invention's examples and the comparative examples described above.

[0077] Experimental design Experiment 1: Comparative experiment on the influence of reinforcement material type on the comprehensive performance of insulation arm Objective: To verify the advantages of basalt fiber used in the present invention over traditional glass fiber in terms of mechanical properties, temperature resistance and corrosion resistance.

[0078] Comparison group: Experimental group: basalt fiberglass reinforced plastic insulation arm sample prepared in Example 1.

[0079] Control group: Glass fiber reinforced plastic insulation arm specimens prepared in comparative example D1. All specimens were cut from the wall of the corresponding insulation arm according to standard requirements.

[0080] Main testing equipment: Universal material testing machine (equipped with corresponding fixtures and extensometer); thermal deformation temperature tester; constant temperature oven; analytical balance (accuracy 0.0001g); glassware (beakers, measuring cylinders, etc.); cutting and sample preparation equipment; vernier calipers and micrometers;

[0081] Experimental steps: (a) Mechanical properties test: Tensile Strength and Modulus: Prepare standard tensile specimens from the insulating arm tube wall of the experimental and control groups according to GB / T 1447-2005, "Test Method for Tensile Properties of Fiber-Reinforced Plastics," or ASTM D3039. Tensile tests were performed using a universal testing machine at room temperature (23 ± 2°C) at a constant loading rate (e.g., 2 mm / min). The maximum tensile load and elongation at break were recorded, and the tensile strength and tensile modulus were calculated. At least five valid specimens were tested for each group.

[0082] Flexural Strength and Modulus: Prepare standard flexural specimens from the insulating arm tube wall of the experimental and control groups according to GB / T 1449-2005, "Fiber-Reinforced Plastics, Test Method for Flexural Properties," or ASTM D790. Perform the test using a three-point bending method on a universal testing machine at a constant loading rate (e.g., 5 mm / min). Record the maximum bending load and deflection, and calculate the flexural strength and flexural modulus. Test at least five valid specimens per group.

[0083] End-bearing capacity simulation: For complete insulating arms (specific length, e.g., 1.5 meters) prepared in Example 1 and Comparative Example D1, simulate actual use. One end is fixed, and a vertical load is applied to the other end (the end with the characteristic hole or the corresponding end). The load is gradually increased until failure or a preset limit (e.g., greater than 1 ton) is reached. The failure load or maximum load is recorded.

[0084] (b) Temperature resistance test: Heat Deflection Temperature (HDT): Prepare standard specimens from the insulating arm tube wall of the experimental and control groups according to GB / T 1634-2004, "Plastics—Determination of Deflection Temperature under Load," or ASTM D648. Test the HDT under a specified load (e.g., 1.80 MPa) at a heating rate of 2°C / min.

[0085] Mechanical property retention rate after high temperature treatment: Place two sets of standard mechanical specimens (tensile or bending) in a certain high temperature environment (for example, 150°C or set according to application requirements) for 24 hours. After cooling to room temperature, perform mechanical property testing again to calculate the mechanical property retention rate after high temperature treatment.

[0086] (c) Chemical Corrosion Resistance Test: Select representative corrosive media, such as 10% sulfuric acid solution, 10% sodium hydroxide solution, or saturated sodium chloride solution. Completely immerse test specimens (e.g., 20 mm x 20 mm x tube wall thickness) from the experimental and control groups in these media and maintain them at room temperature for a specified period of time (e.g., 7 or 30 days). After removal, rinse with deionized water, dry, and measure mass change. Observe the surface for any obvious signs of corrosion, swelling, or cracking. Optionally, perform mechanical property testing on the corroded specimens to assess the degree of performance degradation.

[0087] Table 1: Comparative data on the effect of reinforcement material type on insulation arm performance

[0088] Summary: The unique chemical composition and silicate network structure of basalt fiber give it excellent intrinsic stiffness and strength, making the mechanical properties of the composite material reinforced by it (such as Example 1) far superior to those of glass fiber products (Comparative Example D1). This is due to its stronger interatomic bonding and optimized microstructure.

[0089] Basalt fiber's higher melting and softening points give it improved structural stability and mechanical property retention at high temperatures. Consequently, the insulating arm of Example 1 has a higher heat deformation temperature and maintains high strength after high-temperature aging, demonstrating its reliability in wide-temperature applications.

[0090] The dense silicon-oxygen network and various metal oxides on the surface of basalt fiber give it greater resistance to chemical attack. Compared with glass fiber, which is easily corroded by acids and alkalis, basalt fiber exhibits better chemical inertness, significantly improving the durability and service life of the composite material in corrosive environments.

[0091] Experiment 2: Comparative experiment on the influence of precise structural features on the application adaptability of insulating arms Purpose: The core of this experiment is to explore the crucial role that precisely designed geometric features on the insulating arm—such as the specific end bevels, the Z-shaped arrangement of through-holes, and the square array of holes—play in determining its ease of assembly, fit accuracy, and ultimately suitability for specific engineering applications. By comparing the design with a control sample lacking these features, the value of this invention in structural innovation will be revealed.

[0092] Comparison group: Experimental group: basalt fiberglass reinforced plastic insulation arm with complete structural characteristics prepared in Example 1.

[0093] Control group: Comparative Example D2 prepared only simple square tubular (flat-cut at both ends, without holes) basalt fiberglass reinforced plastic insulation arms.

[0094] Auxiliary facilities: Custom assembly test bench: A specially designed metal frame with docking bevels, bolt holes and locating pin holes that match the precise features of the insulation arm.

[0095] Standard fasteners: M10 and M12 bolts, nuts, washers, and dowel pins of matching diameter.

[0096] Measuring tools: feeler gauge (0.02~1.00mm), digital vernier caliper, angle ruler, torque wrench.

[0097] Auxiliary tools: rubber hammer, marker, stopwatch.

[0098] Recording equipment: digital camera, experimental notebook.

[0099] Experimental steps: (a) Simulated assembly experiment: Design a simulated mounting structure or fixture that requires the insulating arms to have specific bevel angles for proper fit and requires bolt connections or pins to be positioned using Z-shaped and square holes. Assemble the insulating arms of the experimental and control groups to this simulated structure.

[0100] Evaluation Metrics: The ease of assembly (whether additional adjustments are required or forced installation is required); How tightly the beveled surfaces fit together (use a feeler gauge to check the gap); The alignment accuracy of the holes (whether the bolt or pin can pass through and connect smoothly); Stability after assembly.

[0101] (b) Stress Distribution Observation (Optional, If Conditions Allow): If conditions permit, strain gauges may be attached to the edges of the holes in the insulating arms of the experimental group. Under simulated load conditions (e.g., applying a certain tensile or torsional force through the holes), the stress concentration around the holes can be observed. Although Comparative Example D2 does not have holes, this test primarily verifies the design of Example 1 to ensure that excessive stress concentration is avoided.

[0102] (c) Functional Applicability Assessment: Considering the intended application scenarios of the insulating arms of the present invention (e.g., supporting and insulating power facilities, or structural connectors for specific equipment), evaluate the differences between the two insulating arms in meeting the functional requirements of the scenario. For example, if the Z-shaped hole is used to route special cables or secure specific accessories, then Comparative Example D2 clearly cannot meet this function.

[0103] Table 2: Comparative evaluation of insulation arm structural characteristics and assembly adaptability

[0104] Note: 11 = very difficult / no fit, 5 = very smooth / perfect fit; 2 1 = very difficult / impossible to get through, 5 = very smooth; 3 1 = Very loose, 5 = Very secure. N / A = Not Applicable.

[0105] The precise geometric features of the insulating arms, such as the specific end bevels and precisely arranged hole system, are the physical foundation for efficient assembly and functional integration. The structural design of Example 1 ensures optimized contact, a predetermined angle, and a secure connection with the mating components, which is crucial for effective load transfer and the avoidance of stress concentration. In contrast, the simple structure of Comparative Example D2, lacking these key features, exhibits significant compatibility issues when faced with complex docking requirements.

[0106] Precision machining imparts a specific macroscopic form to the insulating arm, transforming it from a basic profile into a specialized component that meets specific engineering requirements. These structural details—the bevels, hole positions, and their layout—not only optimize the mechanical load path but also simplify assembly logic. These details are key to ensuring the insulating arm reliably performs its intended function in its target application, embodying the core value of transforming design into practical application.

[0107] Experiment 3: Comparative experiment on the effect of coupling agents on the interface bonding and comprehensive performance of composite materials Objective: To demonstrate that surface treatment of basalt fiber with a silane coupling agent and / or its addition to a resin system can significantly improve the interfacial bonding strength between the fiber and the resin matrix, thereby enhancing the overall mechanical properties and durability of the composite material.

[0108] Comparison group: Experimental group: basalt fiberglass reinforced plastic insulation arm sample prepared in Example 1 (coupling agent was used).

[0109] Control group: basalt fiberglass reinforced plastic insulation arm sample prepared in comparative example D3 (no coupling agent treatment and no coupling agent added to the resin).

[0110] Test instruments and equipment: Scanning electron microscope (SEM), preferably equipped with energy dispersive spectrometer (EDS); universal testing machine with precise force and displacement sensors; specialized fixture for short beam shear strength testing; constant temperature and humidity test chamber; precision electronic balance; equipment for specimen cutting, grinding, and polishing; and vacuum impregnation or ultrasonic cleaning equipment (for specimen pretreatment).

[0111] Experimental steps: (a) Interface performance evaluation: Scanning electron microscopy (SEM) observation: Fracture specimens from mechanical tests (such as tensile or flexural tests) were collected from both the experimental and control groups and observed using a scanning electron microscope after metallization. The focus was on the fiber-matrix interface. The experimental group should demonstrate good resin infiltration and adhesion to the fiber surface, with minimal fiber pullout and a presence of resin on the surface. The control group may exhibit a smooth fiber surface, significant gaps between the fiber and the resin, and significant fiber pullout.

[0112] Short beam shear strength (ILSS) test (optional): Test the interlaminar shear strength of two groups of specimens in accordance with GB / T 1450.1-2005 "Fiber-reinforced plastics, test method for interlaminar shear strength" or ASTM D2344. This value can, to a certain extent, reflect the quality of the interlaminar bonding.

[0113] (b) Mechanical property comparison: The tensile strength and flexural strength tests in Experiment 1(a) were repeated, and the mechanical property data of the experimental group and the control group were compared. The experimental group with good interfacial bonding generally showed higher mechanical strength.

[0114] (c) Comparison of Hygrothermal Aging Resistance: Standard mechanical specimens from the experimental and control groups are placed in a humid and hot environment (e.g., 60°C, 95% relative humidity) and aged for a specified period of time (e.g., 7 days or longer). After removal, mechanical properties are tested at room temperature, and the performance retention before and after aging is compared. Materials with poor interfacial bonding typically experience more significant performance degradation in humid and hot environments.

[0115] Table 3: Effects of coupling agent application on composite material interface and overall performance

[0116] The hydrolyzed silanol group at one end of the silane coupling agent molecule can form a stable chemical bond (such as Si-O-Si) with the surface of the basalt fiber, achieving a strong anchoring of the coupling agent to the inorganic fiber. This chemical bond is far superior to physical adsorption and lays the foundation for the interfacial compatibility between the organic resin and the inorganic fiber.

[0117] The other end of the coupling agent molecule carries an organic functional group (such as an epoxy group) that is reactive or compatible with epoxy resin. This creates a continuous interfacial transition layer between the fiber and the resin. This interfacial layer improves resin wetting of the fiber, reduces defects, and efficiently transfers stress from the resin to the fiber, fully utilizing the load-bearing properties of the reinforcing fiber.

[0118] Under harsh conditions such as humidity and heat, interfaces without coupling agent protection are susceptible to moisture erosion and failure. The dense chemical bonding interface formed by the coupling agent, along with its certain hydrophobicity, can effectively block moisture and protect the interface structure, thereby maintaining the stable performance of the composite material in harsh environments.

[0119] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A basalt fiberglass reinforced plastic insulation arm, characterized in that: The arm body (1) of the insulating arm is made of the following components through pultrusion and subsequent mechanical processing: Reinforcement material: basalt fiber or its fabric, 50-75 parts by mass; Matrix material: epoxy resin system, 25-50 parts by mass; Auxiliary components: 0.5-2 parts by mass of coupling agent and 1-5 parts by mass of flame retardant; Furthermore, the arm body (1) is a square tubular object, and one end of the arm body (1) has a beveled surface (2), and a side wall of the arm body (1) close to one end of the beveled surface (2) is provided with five circular through holes (3) arranged in a Z shape, and a side wall of the other end of the arm body (1) is provided with four circular through holes (4) arranged in a square shape.

2. The basalt fiberglass reinforced plastic insulation arm according to claim 1, characterized in that: The basalt fiber is made of natural volcanic extrusive rock as raw material, which is melted at a temperature of 1450° C. to 1550° C. and drawn through a platinum-rhodium alloy drawing plate to form a continuous fiber.

3. The basalt fiberglass reinforced plastic insulation arm according to claim 1, characterized in that: The surface of the reinforcing material basalt fiber is treated with a silane coupling agent.

4. The basalt fiberglass reinforced plastic insulation arm according to claim 1, characterized in that: The flame retardant is a compound of aluminum hydroxide and microencapsulated red phosphorus.

5. The basalt fiberglass reinforced plastic insulation arm and its preparation process according to claim 1, characterized in that: The epoxy resin system comprises bisphenol A epoxy resin, an acid anhydride curing agent and an imidazole accelerator.

6. A preparation process for basalt fiberglass reinforced plastic insulation arm, characterized in that: A basalt fiberglass reinforced plastic insulation arm according to any one of claims 1 to 5 comprises the following steps: S1. Raw material preparation: preparing basalt fiber or its fabric as a reinforcing material, and an epoxy resin matrix mixture containing an epoxy resin, a curing agent, an accelerator, and a flame retardant; S2 pultrusion: After the basalt fiber or its fabric is impregnated with the epoxy resin matrix mixture, it is pultruded and cured through a heated molding die having a square inner cavity to form a continuous square tubular profile; S3 cutting: the solidified square tubular profile is cut to a predetermined length to obtain a semi-finished insulating arm; S4. Subsequent machining: machining the semi-finished insulating arm product to form the beveled surface, the five circular through holes arranged in a Z-shape, and the four circular through holes arranged in a square shape.

7. The process for preparing a basalt fiberglass reinforced plastic insulation arm according to claim 6, characterized in that: In step S1, the basalt fiber or its fabric used as the reinforcing material is pre-surface treated with a silane coupling agent.

8. The process for preparing a basalt fiberglass reinforced plastic insulation arm according to claim 6, characterized in that: The curing temperature of the heating molding die in step S2 is in the range of 150°C to 220°C.

9. The process for preparing a basalt fiberglass reinforced plastic insulation arm according to claim 6, characterized in that: The subsequent machining in step S3 includes: using a CNC machine tool to cut one end of the semi-finished insulating arm to form a beveled surface, and accurately machining the side wall thereof to form the circular through holes in the Z-shaped arrangement and the circular through holes in the square arrangement.

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