A resin matrix composition for an insulated boom of an aerial work platform and its preparation method

Abstract

This invention discloses a resin matrix composition and preparation method for an insulated boom of an aerial work platform. The raw materials of the resin matrix composition, by weight, include the following components in parts by weight: 100 parts epoxy resin matrix, 75-85 parts curing agent, 5-10 parts island-type rubber toughening agent, 1-5 parts surface-modified nano-silica, 0.1-1.0 parts accelerator, and 0.1-0.5 parts defoamer. The island-type rubber toughening agent is a pre-reacted or physically blended epoxy resin containing a rubber phase, which can precipitate spherical rubber particles with a diameter of 0.1-2.0 μm during the curing process, forming a typical island two-phase structure. The surface-modified nano-silica is fumed silica that has been surface-treated with a silane coupling agent. This invention utilizes a combination of island-type rubber toughening agent and nano-silica particles to construct a "soft-hard synergistic" microstructure, which significantly improves the impact toughness and crack resistance of epoxy resin matrix while maintaining high mechanical modulus and enhancing high-voltage electrical insulation performance.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a resin matrix composition and preparation method for an insulated boom of an aerial work platform. Background Technology

[0002] Aerial work platforms (especially insulated boom lifts) are widely used in live-line maintenance work in power systems. Their core component—the insulated boom—is typically made of epoxy resin-based fiber-reinforced polymer (FRP) composite material. During operation, the insulated boom not only needs to withstand the weight of the operators and equipment but also faces complex mechanical environments such as wind loads, sudden stops and swaying, and alternating high and low temperatures. More importantly, as a safety barrier for live-line work, it must maintain extremely high insulation reliability under high-voltage electric fields of tens or even hundreds of kilovolts. Therefore, the insulated boom material must simultaneously possess high mechanical strength, high toughness, and excellent dielectric properties.

[0003] Currently, bisphenol A or alicyclic epoxy resin systems are commonly used in insulating arms. While these systems exhibit high cross-linking density after curing and possess excellent rigidity and adhesion, they inherently suffer from brittleness, poor impact resistance, and weak fatigue resistance. Under long-term extension, contraction, friction, and dynamic loads, the matrix resin is prone to developing microcracks. These microcracks not only reduce the mechanical load-bearing capacity of the boom, but more dangerously, under the influence of a high-voltage electric field, partial discharge can easily occur within the cracks, leading to the growth of electrical trees. Ultimately, this can cause the insulating arm to break down at voltages far below its design voltage, seriously threatening the lives of workers.

[0004] To address the brittleness of epoxy resins, existing technologies often employ toughening modifications using rubber elastomers or thermoplastic resins (such as carboxyl-terminated nitrile butadiene rubber (CTBN), core-shell rubber particles, and island-type toughening agents). These modifiers effectively induce crazing and shear banding by forming dispersed "island" structures within the resin matrix, thereby dissipating impact energy. However, this method of simply introducing a "soft phase" suffers from significant "loss of rigidity and heat resistance." The addition of the rubber phase drastically reduces the flexural modulus and glass transition temperature of the cured material, resulting in insufficient stiffness of the insulating arm during extension operations, leading to significant deflection (sag) and swaying, affecting operational stability. Furthermore, some rubber phases readily absorb moisture in high-humidity environments, increasing the dielectric loss factor of the insulating material.

[0005] On the other hand, the use of rigid inorganic nanoparticles (such as nano-silica and nano-alumina) for toughening and reinforcement has also been a research hotspot in recent years. Although rigid nanoparticles can improve the modulus and heat resistance of materials to a certain extent and inhibit crack propagation through the pinning effect, their toughening effect is relatively limited and cannot meet the stringent requirements of insulation arms for impact resistance. More challenging is that nanoparticles have a huge specific surface area and are prone to agglomeration in epoxy resin systems with high viscosity. Agglomerates not only fail to provide reinforcement but also become stress concentration points and weak points in insulation within the material, inducing tip discharge under high voltage and causing insulation performance to decrease rather than improve.

[0006] In summary, existing epoxy resin materials for insulated arms struggle to simultaneously achieve significant toughening while maintaining high rigidity and high insulation; a fundamental contradiction exists among these three aspects. Currently, research focuses on compounding island-type rubber toughening agents with inorganic nanoparticles, particularly for the specific working conditions of aerial work platform insulated arms. This involves controlling the synergistic effect of the two materials at the microscopic phase level to achieve "toughening without sacrificing rigidity and superior insulation." Therefore, developing a novel soft-hard synergistic composite toughening modification method has significant application value for improving the safety performance and service life of aerial work platform insulated arms in my country. Summary of the Invention

[0007] The purpose of this invention is to provide a resin matrix composition and preparation method for an insulating boom of an aerial work platform, which solves the technical problems in the prior art where the use of rubber alone for toughening leads to a significant decrease in the rigidity and heat resistance of the material, or the use of inorganic nanoparticles alone has limited toughening effect and is prone to agglomeration, resulting in unstable insulation performance.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a resin matrix composition for an insulated boom of an aerial work platform vehicle. The raw materials of the resin matrix composition, by weight, include the following components in parts by weight: 100 parts epoxy resin matrix, 75-85 parts curing agent, 5-10 parts island-type rubber toughening agent, 1-5 parts surface-modified nano silica, 0.1-1.0 parts accelerator, and 0.1-0.5 parts defoamer. The island-type rubber toughening agent is a pre-reacted or physically blended epoxy resin containing a rubber phase, which can precipitate spherical rubber particles with a diameter of 0.1~2.0μm during the curing process, forming a typical island two-phase structure; The surface-modified nano silica is fumed silica that has been surface-treated with a silane coupling agent, and its D50 particle size is 20-30 nm.

[0009] In some possible implementations, the silane coupling agent includes one or more of γ-glycidoxypropyltrimethoxysilane and KH-560.

[0010] In a second aspect, the present invention also provides a method for preparing the resin matrix composition for the insulating boom of an aerial work platform as described in any one of the first aspects, comprising the following steps: The epoxy resin matrix was added to the reaction vessel, heated, and the surface-modified nano-silica was added. The mixture was then dispersed by high-speed mechanical shearing to obtain a mixture. The mixture was transferred to an ultrasonic oscillation container and subjected to ultrasonic oscillation treatment to obtain nano-modified epoxy mother liquor. Island-type rubber toughening agent is added to the nano-modified epoxy mother liquor and stirred at low speed. The thixotropic properties of nano-silica are used to lock the initial distribution of the rubber phase, resulting in a multi-component toughening resin system. Cool down, add curing agent, accelerator and defoamer, and vacuum degas until no bubbles overflow to obtain mixed adhesive; The mixed adhesive is injected into a mold or impregnated with fibers, cured by gradient heating, cooled in the furnace, and demolded to obtain the resin matrix composition for the insulating boom of the aerial work vehicle.

[0011] In some possible implementations, the heating specifically includes heating to 50-70°C. In some possible implementations, the high-speed mechanical shearing dispersion is carried out at 50~70°C and the rotation speed is set to 2000~3000 rpm.

[0012] In some possible implementations, the ultrasonic oscillation process specifically includes setting the time to 30-60 minutes.

[0013] In some possible implementations, the low-speed stirring is carried out at a constant temperature of 50-70°C, with the stirring speed set at 450-550 rpm and the stirring time at 20-30 minutes.

[0014] In some possible implementations, the cooling specifically includes cooling to 40-50°C, and the vacuum degassing treatment is carried out in a vacuum degassing chamber for 20-40 minutes.

[0015] In some possible implementations, the curing by gradient temperature increase specifically includes: holding at 80±5℃ for 3-4 hours, increasing to 120±5℃ and holding for 1-2 hours, and continuing to increase to 140±5℃ and holding for 3-5 hours.

[0016] The present invention provides a resin matrix composition and preparation method for an insulated boom of an aerial work platform, which has the following advantages compared with the prior art: 1. The "soft and hard synergy" effect of mechanical properties: such as Figure 2As shown in (b), this invention utilizes micron-sized rubber particles formed by HS-100 as "island" structures, which act as stress concentration points, inducing the matrix to generate crazes and shear bands to dissipate impact energy. Simultaneously, rigid nano-silica particles dispersed in the matrix act as "pinning" structures, forming a three-phase structure with the matrix and rubber particles. The resin is the first phase (i.e., the "sea" phase), primarily bearing the structural load and high-voltage insulation function of the insulating arm, providing necessary coating and support for the dispersed phase; the second phase is a micron-sized spherical rubber dispersed phase (i.e., the "island" phase); the third phase is rigid nano-silica particles (i.e., the "hard" dispersed phase), which, compared to conventional crack propagation (i.e.,... Figure 2 (as shown in (a)), this multi-toughening mechanism not only significantly improves the impact resistance of the insulating arm, but also effectively suppresses partial discharge and electrical tree growth caused by microcrack propagation, thereby achieving a dual improvement in mechanical and insulation properties.

[0017] 2. Rigidity and Heat Resistance Compensation Mechanism: Addressing the modulus reduction issue caused by traditional rubber toughening, this invention introduces high-modulus nano-silica particles to construct a rigid framework, compensating for the rigidity loss caused by the soft phase of the rubber. Test data shows that the composite material prepared by this invention maintains high toughness while retaining over 95% of the flexural modulus of pure epoxy resin, far superior to systems using rubber alone for toughening. This ensures sufficient rigidity of the insulated boom during operation, reducing boom sway.

[0018] 3. Process stability and phase control: The introduction of nano-silica improves the rheological properties (thixotropy) of the resin system, effectively limiting the excessive collision and aggregation of HS-100 rubber particles in the early stage of curing, making the island structure after curing more uniform in size and more stable in distribution, and solving the problem of uneven performance caused by resin flow during the preparation of large insulating arms. Attached Figure Description

[0019] Figure 1 The process flow for dispersing nano-silica; Figure 2 This is a schematic diagram showing the microscopic comparison between epoxy resin and toughened resin. Figure 3 The images show the impact cross-sections before and after epoxy resin toughening. Figure 4 This is a flow chart of the resin curing process. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. At the same time, in the description of the embodiments of this application, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0021] Example 1 This embodiment provides a resin matrix composition for an insulated boom of an aerial work platform. The raw materials include the following components in parts by weight: 100 parts epoxy resin matrix, 85 parts curing agent, 10 parts island-type rubber toughening agent, 3 parts surface-modified nano silica, 0.5 parts accelerator, and 0.3 parts defoamer.

[0022] The island-type rubber toughening agent is a pre-reacted rubber-phase epoxy resin of model HS-100, in which the content of active rubber dispersed phase is about 40%. During the curing process, it can precipitate spherical rubber particles with a diameter of 0.1~2.0μm, forming a typical island two-phase structure. The epoxy resin matrix is ​​bisphenol A type epoxy resin E-51 with an epoxy equivalent of 184-195g / eq. The curing agent is methyltetrahydrophthalic anhydride MeHHPA. The accelerator is BDMA.

[0023] It should be noted that the HS-100 type island-type rubber toughening agent is mainly a rubber granule type toughening agent, produced by Chuzhou Huisheng Electronic Materials Co., Ltd. The specific model name may vary from manufacturer to manufacturer, but the principle and effect are the same.

[0024] The surface-modified nano-silica is fumed silica that has undergone KH-560 surface treatment, with a D50 particle size of 20 nm. The surface treatment specifically refers to immersion followed by drying.

[0025] In other embodiments, the following components may also be included in parts by weight: 75 or 8 parts of curing agent, 5 or 8 parts of island-type rubber toughening agent, 1 or 5 parts of surface-modified nano silica, 0.1 or 1.0 parts of accelerator, and 0.1 or 0.5 parts of defoamer.

[0026] A method for preparing a resin matrix composition for an insulated boom of an aerial work platform, such as... Figure 1 As shown, it includes the following steps: 100 parts of bisphenol A type epoxy resin E-51 were added to the reaction vessel and heated to 60°C to reduce the viscosity of bisphenol A type epoxy resin E-51. 3 parts of surface-modified nano silica were added and the mixture was subjected to high-speed mechanical shear dispersion at 60°C with a rotation speed of 2500 rpm to obtain a mixture.

[0027] The mixture was transferred to an ultrasonic oscillation container and subjected to ultrasonic oscillation at 60°C for 45 minutes to open up the nano-aggregates using the cavitation effect, resulting in a homogeneous nano-modified epoxy mother liquor.

[0028] Ten parts of HS-100 island-type rubber toughening agent were added to the nano-modified epoxy mother liquor, and the mixture was stirred at a constant temperature of 60℃ at a low speed of 500 rpm for 30 minutes. The thixotropic properties of the surface-modified nano silica were used to lock the initial distribution of the rubber phase, thus obtaining a multi-component toughening resin system.

[0029] Cool to 45℃, add 85 parts of methyltetrahydrophthalic anhydride (MeHHPA), 0.5 parts of BDMA and 0.3 parts of defoamer, and perform vacuum degassing treatment in a vacuum degassing chamber at a vacuum degree of -0.098 MPa for 30 minutes until no bubbles overflow.

[0030] Inject the mixed adhesive solution into a mold or impregnate the fibers, such as Figure 4 As shown, the resin matrix composition for the insulating boom of the aerial work platform is obtained by gradient heating, holding at 80℃ for 3 hours, raising to 120℃ and holding for 1 hour, and continuing to raise to 140℃ and holding for 3 hours for curing. After cooling to room temperature in the furnace, it is demolded.

[0031] In other embodiments, heating can be set to 50 or 70°C; high-speed mechanical shear dispersion can be carried out at 50 or 70°C, and the rotation speed can be set to 2000 or 3000 rpm; ultrasonic oscillation treatment time can be set to 30 or 60 minutes; low-speed stirring can be carried out at a constant temperature of 50 or 70°C, with a stirring speed of 450 or 550 rpm and a stirring time of 20 or 25 minutes; cooling can be set to 40 or 50°C, and vacuum degassing treatment time can be 20 or 40 minutes; curing can be set by gradient heating, specifically including: holding at 80±5°C for 3.5 or 4 hours, holding at 120±5°C for 1.5 or 2 hours, and holding at 140±5°C for 4 or 5 hours.

[0032] Comparative Example 1 The only difference between this comparative example and Example 1 is that it includes the following components in parts by weight: 100 parts of bisphenol A type epoxy resin E-51, 85 parts of methyltetrahydrophthalic anhydride MeHHPA, and 0.5 parts of BDMA.

[0033] Comparative Example 2 The only difference between this comparative example and Example 1 is that it includes the following components in parts by weight: 100 parts of bisphenol A type epoxy resin E-51, 10 parts of HS-100 island-type rubber toughening agent, 85 parts of methyltetrahydrophthalic anhydride MeHHPA, and 0.5 parts of BDMA.

[0034] Comparative Example 3 The only difference between this comparative example and Example 1 is that it includes the following components in parts by weight: 100 parts of bisphenol A type epoxy resin E-51, 3 parts of surface-modified nano silica, 85 parts of methyltetrahydrophthalic anhydride MeHHPA, and 0.5 parts of BDMA.

[0035] The products of Example 1 and Comparative Examples 1-3 were tested according to national standards GB / T1043.1 (notched impact strength of simply supported beams), GB / T9341 (flexural modulus), and GB / T1408.1 (power frequency breakdown voltage). The test data are shown in Table 1. Table 1 Figure 3 This paper presents a comparison of the microstructure of the impact fracture surface before and after toughening of the epoxy resin matrix in embodiments of the present invention. Figure 3 (a) It can be seen that the cross-section of the unmodified pure epoxy resin casting exhibits typical brittle fracture characteristics. The fracture surface is smooth and flat overall, with only a few river-like stripes. The crack propagation path is straight and there are no obvious signs of obstruction, indicating that the cracks penetrate rapidly during the failure process and the energy dissipation is extremely low.

[0036] In comparison, Figure 3 (b) The fracture morphology after synergistic toughening with nano-silica and rubber shows a fundamental change, with significant surface roughness and complex tear texture. Numerous irregular ductile tear ridges and uneven structures are visible on the fracture surface, indicating that the dispersed phase effectively induces crack deflection and pinning effects, forcing the crack to frequently change its path and generate new surfaces during propagation. This significantly increases the fracture surface area and greatly improves the resin matrix's ability to absorb and dissipate impact energy, confirming that the toughening method described in this invention achieves a transformation from brittle fracture to ductile fracture.

[0037] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A resin matrix composition for an insulated boom of an aerial work platform, characterized in that, The raw materials of the resin matrix composition, by weight, include the following components in parts by weight: 100 parts epoxy resin matrix, 75-85 parts curing agent, 5-10 parts island-type rubber toughening agent, 1-5 parts surface-modified nano silica, 0.1-1.0 parts accelerator, and 0.1-0.5 parts defoamer. The island-type rubber toughening agent is a pre-reacted or physically blended epoxy resin containing a rubber phase, which can precipitate spherical rubber particles with a diameter of 0.1~2.0μm during the curing process, forming a typical island two-phase structure; The surface-modified nano silica is fumed silica that has been surface-treated with a silane coupling agent, and its D50 particle size is 20-30 nm.

2. The resin matrix composition for the insulated boom of an aerial work platform according to claim 1, characterized in that, Silane coupling agents include one or more of γ-glycidoxypropyltrimethoxysilane and KH-560.

3. A method for preparing a resin matrix composition for an insulated boom of an aerial work platform according to any one of claims 1-2, characterized in that, Includes the following steps: The epoxy resin matrix was added to the reaction vessel, heated, and the surface-modified nano-silica was added. The mixture was then dispersed by high-speed mechanical shearing to obtain a mixture. The mixture was transferred to an ultrasonic oscillation container and subjected to ultrasonic oscillation treatment to obtain nano-modified epoxy mother liquor. The island-type rubber toughening agent was added to the nano-modified epoxy mother liquor and stirred at low speed. Cool down, add curing agent, accelerator and defoamer, and vacuum degas until no bubbles overflow to obtain mixed adhesive; The mixed adhesive is injected into a mold or impregnated with fibers, cured by gradient heating, cooled in the furnace, and demolded to obtain the resin matrix composition for the insulating boom of the aerial work vehicle.

4. The preparation method according to claim 3, characterized in that, The heating specifically includes heating to 50~70℃.

5. The preparation method according to claim 3, characterized in that, The high-speed mechanical shearing and dispersion is carried out at 50~70℃, and the rotation speed is set at 2000~3000rpm.

6. The preparation method according to claim 3, characterized in that, The ultrasonic oscillation treatment specifically includes setting the time to 30-60 minutes.

7. The preparation method according to claim 3, characterized in that, The low-speed stirring is carried out at a constant temperature of 50~70℃, with the stirring speed set at 450-550rpm and the stirring time at 20-30 minutes.

8. The preparation method according to claim 3, characterized in that, The cooling process specifically includes cooling to 40~50℃, and the vacuum degassing treatment is carried out in a vacuum degassing chamber for 20~40 minutes.

9. The preparation method according to claim 3, characterized in that, The curing process via gradient temperature increases specifically includes: maintaining a temperature of 80±5℃ for 3-4 hours, increasing the temperature to 120±5℃ and maintaining it for 1-2 hours, and then increasing the temperature to 140±5℃ and maintaining it for 3-5 hours.

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