Organic microcapsule phase change synergistic a-class flame-retardant pultrusion composite material and preparation method thereof

Abstract

The present application relates to the field of flame-retardant pultruded composites, and particularly relates to an organic microcapsule phase change synergistic A-grade flame-retardant pultruded composite material and a preparation method thereof, comprising the following components in percentage by mass: reinforcing body 75-85%, resin matrix 15-25%; the resin matrix comprises the following components in mass fraction: flame-retardant resin 55-65 parts, organic microcapsule phase change material 8-15 parts, inorganic flame-retardant filler 15-22 parts, synergistic flame-retardant agent 2-3 parts, active diluent 8-12 parts, curing agent 85-95 parts, accelerator 0.4-0.9 parts, coupling agent 0.4-0.7 parts, internal release agent 0.2-0.4 parts; the organic microcapsule phase change material is inorganic-coated organic phase change microcapsule, the phase change temperature is 70-90 DEG C, the latent heat is greater than or equal to 170 J / g, the microcapsule particle size is 10-60 microns, and the coating thickness is 100-250 nm; the present application has the following beneficial effects: good flame-retardant effect, excellent mechanical properties, and good engineering application prospect.

Description

Technical Field

[0001] This invention relates to the field of flame-retardant pultruded composite materials, and particularly to an organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material and its preparation method. Background Technology

[0002] Fiber-reinforced pultruded composites are widely used in construction, transportation, and power industries due to their advantages such as lightweight, high strength, corrosion resistance, and ease of molding. However, the flame retardant properties of traditional pultruded composites are generally low; ordinary epoxy pultruded materials can only achieve UL94 V-0 or B1 ratings, which is insufficient to meet Class A fire protection requirements for buildings. To achieve Class A flame retardancy, existing technologies typically employ highly filled inorganic flame-retardant fillers (such as aluminum hydroxide and magnesium hydroxide), but this method faces two major technical bottlenecks: first, the addition of a large amount of inorganic filler leads to a sharp increase in the viscosity of the resin system, resulting in poor fiber wettability and problems such as mold blockage and surface defects in the product during the pultrusion process; second, the poor interfacial compatibility between inorganic fillers and the organic resin matrix leads to a significant decrease in the mechanical properties of the composite material.

[0003] On the other hand, organic phase change materials are widely used in the field of thermal management due to their advantages such as large latent heat of phase change and adjustable phase change temperature. However, traditional organic phase change materials such as paraffin and fatty acids are inherently flammable. Although microencapsulation can solve the leakage problem to some extent, conventional organic encapsulation wall materials such as urea-formaldehyde resin and melamine-formaldehyde resin have limited flame retardant properties, and direct addition will still reduce the overall fire safety of the composite material.

[0004] Therefore, how to achieve a synergistic improvement in Class A flame retardancy and thermal management functions without sacrificing the formability of the pultrusion process and the mechanical properties of the composite material is a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material and its preparation method, which achieves a synergistic improvement in Class A flame retardancy and thermal management function without sacrificing the pultrusion process formability and the mechanical properties of the composite material.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material comprises the following components, by mass percentage: 75%~85% reinforcement and 15%~25% resin matrix; wherein the resin matrix comprises the following components by mass percentage: 55~65 parts flame-retardant resin, 8~15 parts organic microcapsule phase change material, 15~22 parts inorganic flame-retardant filler, 2~3 parts synergistic flame retardant, 8~12 parts reactive diluent, 85~95 parts curing agent, 0.4~0.9 parts accelerator, 0.4~0.7 parts coupling agent, and 0.2~0.4 parts internal release agent;

[0008] The organic microcapsule phase change material is an inorganic-encapsulated organic phase change microcapsule with a phase change temperature of 70~90℃, a latent heat of ≥170J / g, a microcapsule particle size of 10~60μm, and a coating layer thickness of 100~250nm.

[0009] The combustion performance of the composite material meets the requirements of GB 8624-2012 A2-s1-d0-t0 grade, with a total heat release per unit area ≤7.5 MJ / m². 2 Tensile strength ≥650MPa, flexural strength ≥700MPa, profile density 2100~2200kg / m³ 3 .

[0010] Preferably, the reinforcement is a continuous fiber reinforcement, selected from one or more of alkali-free glass fiber, carbon fiber, and aramid fiber, with a fiber volume fraction of 70% to 82%, and is laid up using a continuous yarn and felt composite layer or a single continuous yarn layer.

[0011] Preferably, the flame-retardant resin is a halogen-free flame-retardant thermosetting resin adapted to the pultrusion process, selected from one or more of epoxy resin, phenolic epoxy resin, o-cresol resin, and vinyl ester resin, with a total calorific value of 30.0~38.0 MJ / kg; the reactive diluent is selected from glycidyl ether reactive diluents; the curing agent is selected from one of acid anhydride or amine curing agents; the accelerator is selected from quaternary phosphate salt or tertiary amine accelerators; and the coupling agent is selected from silane coupling agents or titanate coupling agents.

[0012] Preferably, the resin matrix further includes 0.2 to 0.4 parts of smoke suppressant, which is selected from molybdenum-based and tin-based smoke suppressants; the inorganic flame retardant filler is selected from one or more of aluminum hydroxide and magnesium hydroxide, with a particle size of 1 to 10 μm.

[0013] Preferably, the coating layer of the organic microcapsule phase change material is selected from one of silica, melamine-formaldehyde resin, and urea-formaldehyde resin; the organic phase change material is selected from one or more of fatty acid-based, paraffin-based, and polyol-based organic phase change materials.

[0014] Preferably, the synergistic flame retardant is selected from one or more of expandable graphite, nano-montmorillonite, and carbon black.

[0015] A method for preparing an organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material includes the following steps:

[0016] (1) Preparation of resin system: Flame retardant resin, organic microcapsule phase change material, inorganic flame retardant filler, synergistic flame retardant, reactive diluent, coupling agent and smoke suppressant are put into a mixing device and mixed for 15-25 min at 20~40℃ and vacuum degree ≤-0.08MPa to obtain component A; curing agent, accelerator and internal release agent are mixed evenly to obtain component B; component A and component B are mixed at a mass ratio of 100:85~95, and the viscosity of the mixed system is controlled to be 600~1500mPa·s;

[0017] (2) Impregnation and preforming: The continuous fiber reinforcement is impregnated into the resin system prepared in step (1) through an impregnation tank. The impregnation temperature is controlled below the phase change temperature of the organic microcapsule phase change material to avoid premature liquefaction of the organic microcapsule phase change material. Then, the fiber layup is sorted and excess resin is removed through a preforming mold.

[0018] (3) Pultrusion curing: The preformed fiber-resin composite is fed into the pultrusion mold and multi-stage gradient temperature control is adopted. The mold temperature is 100~120℃, 130~150℃ and 160~180℃ respectively, and the traction speed is 0.2~0.8m / min to achieve continuous curing.

[0019] (4) Post-processing: Cut and polish the cured profile to obtain the finished product.

[0020] Preferably, in step (1), the stirring speed of the mixing equipment is 200~600 r / min; in step (3), the pressure of the pultrusion die is controlled at 8~18 MPa, and the curing time is 2~6 min.

[0021] As a preferred option, in step (2), the fiber impregnation rate is controlled at 75%~95%; in step (4), the finished product cutting accuracy is ±0.5mm, and the surface roughness Ra of the profile after grinding is ≤1.6μm.

[0022] An application of the aforementioned composite material is to use it in photovoltaic brackets, power poles, building profiles, and pipe gallery structural components.

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. By introducing organic microcapsule phase change materials and coordinating them with inorganic flame-retardant fillers and synergistic flame retardants, the composite material of this invention can actively absorb a large amount of heat in the early stage of a fire through the phase change materials, delay the internal temperature rise of the material, significantly reduce the total heat release value, and meet the GB 8624-2012 A2-s1-d0-t0 level in terms of combustion performance, which is different from the traditional pultruded composite materials that can only reach the B1 level.

[0025] 2. While achieving Class A flame retardancy, the present invention still maintains excellent mechanical properties, with tensile strength ≥650MPa and flexural strength ≥700MPa;

[0026] 3. The impregnation temperature is controlled below the microcapsule phase change temperature to avoid premature liquefaction of the phase change material, which could lead to leakage or bubbles. In addition, multi-stage gradient curing is adopted, which has good process adaptability and is suitable for continuous pultrusion production.

[0027] 4. It adopts a halogen-free flame retardant system, combined with molybdenum-based or tin-based smoke suppressants, resulting in low smoke density and t0 level smoke toxicity during combustion, which is in line with the development direction of green building materials;

[0028] 5. Due to the active heat absorption of phase change materials and the char-forming heat insulation effect of synergistic flame retardants, the amount of inorganic flame retardant filler can be controlled at 15~22 parts, which is lower than that of traditional high-filler systems. This not only reduces the profile density and the weight of the component, but also improves the resin's wettability to the fiber and reduces the risk of mold blockage during pultrusion.

[0029] 6. The composite material of this invention has the advantages of being Class A flame retardant, lightweight and high-strength, corrosion resistant, and continuously moldable. It is particularly suitable for structural components with stringent fire safety requirements, such as photovoltaic brackets, power poles, building profiles, and pipe gallery structural components, and has good prospects for engineering applications. Detailed Implementation

[0030] The present invention will now be described in further detail.

[0031] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0032] Example 1

[0033] Raw materials used in the examples:

[0034] Alkali-free glass fiber: untwisted roving, linear density 2400 tex;

[0035] Flame-retardant epoxy resin: Total calorific value 35.2 MJ / kg;

[0036] Organic microcapsule phase change material: self-made, with paraffin as the core material, melting point 80℃, latent heat 195J / g, silica as the coating layer, coating layer thickness 150nm, and microcapsule average particle size 35μm;

[0037] Aluminum hydroxide: particle size 5μm;

[0038] Expandable graphite: expansion ratio 250mL / g;

[0039] Smoke suppressant: Ammonium molybdate, analytical grade;

[0040] Reactive diluent: Butyl glycidyl ether;

[0041] Curing agent: Methyltetrahydrophthalic anhydride;

[0042] Accelerator: Triphenylphosphine;

[0043] Coupling agent: γ-aminopropyltriethoxysilane (KH-550);

[0044] Internal release agent: zinc stearate.

[0045] An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material, by mass percentage: 80% reinforcement, which is alkali-free glass fiber with a fiber volume fraction of 78%, using continuous yarn and composite felt layup; 20% resin matrix.

[0046] The mass fractions of each component in the resin matrix are as follows: 60 parts flame-retardant epoxy resin, 12 parts organic microcapsule phase change material, 18 parts aluminum hydroxide, 2.5 parts expandable graphite, 10 parts reactive diluent, 90 parts curing agent, 0.6 parts accelerator, 0.5 parts coupling agent, 0.3 parts internal release agent, and 0.3 parts smoke suppressant.

[0047] The preparation method is as follows:

[0048] (1) Preparation of resin system: Flame-retardant epoxy resin, organic microcapsule phase change material, aluminum hydroxide, expandable graphite, reactive diluent, coupling agent, and smoke suppressant were put into a vacuum planetary mixer and mixed at 400 r / min for 20 min at 30℃ and vacuum degree -0.09 MPa to obtain component A; curing agent, accelerator, and internal release agent were stirred and mixed at 200 r / min for 5 min at room temperature to obtain component B. Component A and component B were mixed at a mass ratio of 100:90, and the viscosity of the mixed system was controlled to be 900 mPa·s.

[0049] (2) Impregnation and preforming: The continuous glass fiber reinforcement is passed through an impregnation tank, and the impregnation temperature is controlled at 60°C, which is lower than the phase change temperature of the organic microcapsule phase change material (80°C) to ensure that the phase change material inside the microcapsule remains solid. Then, the fiber layup is sorted through a preforming mold, excess resin is removed, and the fiber impregnation rate is controlled at 85%.

[0050] (3) Pultrusion curing: The preformed fiber-resin composite is fed into the pultrusion mold. The mold adopts a three-stage gradient temperature control: the first stage is 110℃, the second stage is 140℃, and the third stage is 170℃. The traction speed is 0.5m / min, the mold pressure is 12MPa, and the curing time is 4min.

[0051] (4) Post-processing: Cut the cured profile according to the length requirements with a cutting accuracy of ±0.5mm. After grinding, the surface roughness of the profile Ra≤1.6μm is obtained to obtain the finished product.

[0052] Example 2

[0053] The difference from Example 1 is that the organic microcapsule phase change material comprises 8 parts by mass, aluminum hydroxide comprises 22 parts by mass, and expandable graphite comprises 2 parts by mass. The viscosity of the mixed resin system is 1050 mPa·s. The pultrusion traction speed is 0.4 m / min.

[0054] Example 3

[0055] The difference from Example 1 is that the organic microcapsule phase change material comprises 15 parts by mass, aluminum hydroxide comprises 15 parts by mass, and expandable graphite comprises 3 parts by mass. The viscosity of the mixed resin system is 780 mPa·s. The pultrusion traction speed is 0.7 m / min.

[0056] Example 4

[0057] The difference from Example 1 is as follows: the organic microcapsule phase change material uses melamine-formaldehyde resin to coat palmitic acid, with a phase change temperature of 72℃, a latent heat of 172 J / g, a coating layer thickness of 120 nm, and an average microcapsule particle size of 50 μm. The flame retardant resin is phenolic epoxy resin with a total calorific value of 31.5 MJ / kg. The inorganic flame retardant filler is magnesium hydroxide with a particle size of 8 μm. The synergistic flame retardant is nano-montmorillonite, 2.5 parts. The curing agent is m-phenylenediamine, 88 parts. The pultrusion die temperature gradient is 100℃, 135℃, 165℃, and the traction speed is 0.3 m / min.

[0058] Example 5

[0059] An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material, by mass percentage: 78% reinforcement, using carbon fiber, 75% fiber volume fraction, using a single continuous yarn layup, and 22% resin matrix.

[0060] The resin matrix consists of the following components by mass: 58 parts flame-retardant epoxy resin, 10 parts organic microcapsule phase change material (silica-coated paraffin with a phase change temperature of 85℃, latent heat of 185J / g, particle size of 45μm, and coating thickness of 180nm), 20 parts inorganic flame-retardant filler (magnesium hydroxide with a particle size of 8μm, compounded with nano-silica at a mass ratio of 8:1), 2.8 parts carbon black as synergistic flame retardant, 11 parts reactive diluent, 88 parts curing agent, 0.7 parts accelerator, 0.6 parts coupling agent, 0.3 parts internal release agent, and 0.3 parts zinc stannate as smoke suppressant.

[0061] The preparation method is as follows:

[0062] (1) Preparation of resin system: Flame-retardant epoxy resin, organic microcapsule phase change material, inorganic flame-retardant filler containing nano-composite powder, synergistic flame retardant, reactive diluent, coupling agent, and smoke suppressant were put into a vacuum planetary mixer and mixed at 500 r / min for 18 min at 25℃ and vacuum degree -0.095 MPa to obtain component A; curing agent, accelerator, and internal release agent were stirred and mixed at 250 r / min for 5 min at room temperature to obtain component B. Component A and component B were mixed at a mass ratio of 100:88, and the viscosity of the mixed system was controlled to be 1100 mPa·s.

[0063] (2) Impregnation and preforming: The continuous carbon fiber reinforcement is passed through an impregnation tank, and the impregnation temperature is controlled at 65°C, which is lower than the phase change temperature of 85°C for organic microcapsule phase change materials. Then, the fiber layup is sorted through a preforming mold, excess resin is removed, and the fiber impregnation rate is controlled at 82%.

[0064] (3) Pultrusion curing: The preformed fiber-resin composite is fed into the pultrusion mold. The mold adopts a three-stage gradient temperature control: the first stage is 115℃, the second stage is 145℃, and the third stage is 175℃. The traction speed is 0.45m / min, the mold pressure is 15MPa, and the curing time is 3.5min.

[0065] (4) Post-processing: Cut the cured profile according to the length requirements with a cutting accuracy of ±0.5mm. After grinding, the surface roughness of the profile Ra≤1.6μm is obtained to obtain the finished product.

[0066] Example 6

[0067] An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material, by mass percentage: 82% reinforcement, using alkali-free glass fiber, fiber volume fraction 80%, using continuous yarn and felt composite layup; 18% resin matrix.

[0068] The components of the resin matrix are as follows: 62 parts phenolic epoxy resin with a total calorific value of 33.5 MJ / kg; 14 parts organic microcapsule phase change material, which is melamine-formaldehyde resin coated with lauric acid, with a phase change temperature of 70℃, a latent heat of 178 J / g, a particle size of 20 μm, and a coating layer thickness of 130 nm; 16 parts inorganic flame retardant filler, which is aluminum hydroxide with a particle size of 3 μm; 2.2 parts synergistic flame retardant, 9 parts reactive diluent, which is ethylene glycol diglycidyl ether; 92 parts curing agent, which is m-phenylenediamine; 0.8 parts tertiary amine DMP-30 accelerator; 0.5 parts titanate coupling agent; and 0.4 parts internal release agent.

[0069] The preparation method is as follows:

[0070] (1) Preparation of resin system: Phenolic epoxy resin, organic microcapsule phase change material, inorganic flame retardant filler, synergistic flame retardant, reactive diluent, and coupling agent were put into a vacuum planetary mixer and mixed at 350 r / min for 22 min under conditions of 35℃ and vacuum degree of -0.08 MPa to obtain component A; curing agent, accelerator, and internal release agent were stirred and mixed at 150 r / min for 8 min at room temperature to obtain component B. Component A and component B were mixed at a mass ratio of 100:92, and the viscosity of the system after mixing was controlled to be 700 mPa·s.

[0071] (2) Impregnation and preforming: The continuous glass fiber reinforcement is passed through an impregnation tank, and the impregnation temperature is controlled at 55°C, which is lower than the phase change temperature of the organic microcapsule phase change material of 70°C. Then, the fiber layup is sorted through a preforming mold, excess resin is removed, and the fiber impregnation rate is controlled at 90%.

[0072] (3) Pultrusion curing: The preformed fiber-resin composite is fed into the pultrusion mold. The mold adopts a three-stage gradient temperature control: the first stage is 105℃, the second stage is 135℃, and the third stage is 165℃. The traction speed is 0.6m / min, the mold pressure is 10MPa, and the curing time is 3min.

[0073] (4) Post-processing: Same as in Example 1.

[0074] Example 7

[0075] An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material, by mass percentage: 76% reinforcement, using aramid fiber, fiber volume fraction 72%, using a single continuous yarn layup, and 24% resin matrix.

[0076] The resin matrix components are as follows: 55 parts vinyl ester resin (total calorific value 37.0 MJ / kg), 9 parts organic microcapsule phase change material (urea-formaldehyde resin coated with pentaerythritol, phase change temperature 88℃, latent heat 190 J / g, particle size 55 μm, coating layer thickness 220 nm), 21 parts inorganic flame retardant filler (aluminum hydroxide, particle size 9 μm), 3 parts expandable graphite synergistic flame retardant (expansive ratio 300 mL / g), 12 parts reactive diluent, 90 parts curing agent, 0.5 parts accelerator, 0.7 parts coupling agent, 0.2 parts internal release agent, and 0.4 parts ammonium molybdate smoke suppressant.

[0077] The preparation method is as follows:

[0078] (1) Preparation of resin system: Vinyl ester resin, organic microcapsule phase change material, inorganic flame retardant filler, synergistic flame retardant, reactive diluent, coupling agent, and smoke suppressant were put into a vacuum planetary mixer and mixed at 600 r / min for 15 min under the conditions of 30℃ and vacuum degree -0.09MPa to obtain component A; curing agent, accelerator, and internal release agent were mixed evenly to obtain component B. Component A and component B were mixed at a mass ratio of 100:90, and the viscosity of the mixed system was controlled to be 1300 mPa·s.

[0079] (2) Impregnation and preforming: The continuous aramid fiber reinforcement is passed through an impregnation tank. The impregnation temperature is controlled at 70℃, which is lower than the phase change temperature of 88℃ for organic microcapsule phase change materials. The fiber impregnation rate is controlled at 78%.

[0080] (3) Pultrusion curing: The mold temperatures were 120℃, 150℃ and 180℃ respectively, the traction speed was 0.25m / min, the mold pressure was 17MPa and the curing time was 5.5min.

[0081] (4) Post-processing: Same as in Example 1.

[0082] Example 8

[0083] An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material, by mass percentage: 85% reinforcement, which is alkali-free glass fiber, with a fiber volume fraction of 82%, using continuous yarn and felt composite layup, and 15% resin matrix.

[0084] The resin matrix components are as follows: 65 parts o-cresol resin with a total calorific value of 31.0 MJ / kg; 13 parts organic microcapsule phase change material, which is silica-coated stearic acid with a phase change temperature of 75℃, a latent heat of 200 J / g, a particle size of 30 μm, and a coating layer thickness of 100 nm; 17 parts inorganic flame retardant filler, which is magnesium hydroxide with a particle size of 2 μm; 2.5 parts synergistic flame retardant, which is a mixture of expandable graphite and nano-montmorillonite in a mass ratio of 1:1; 8 parts reactive diluent; 85 parts curing agent; 0.4 parts accelerator; 0.4 parts coupling agent; 0.3 parts internal release agent; and 0.2 parts ammonium molybdate as smoke suppressant.

[0085] The preparation method is as follows:

[0086] (1) Preparation of resin system: o-cresol resin, organic microcapsule phase change material, inorganic flame retardant filler, synergistic flame retardant, reactive diluent, coupling agent, and smoke suppressant were put into a vacuum planetary mixer and mixed at 200 r / min for 25 min under the conditions of 20℃ and vacuum degree -0.10 MPa to obtain component A; curing agent, accelerator, and internal release agent were mixed evenly to obtain component B. Component A and component B were mixed at a mass ratio of 100:85, and the viscosity of the system after mixing was controlled to be 1500 mPa·s.

[0087] (2) Impregnation and preforming: The impregnation temperature is controlled at 60℃, which is lower than the phase change temperature of 75℃. The fiber impregnation rate is controlled at 95%.

[0088] (3) Pultrusion curing: The mold temperature is 100℃, 130℃ and 160℃ respectively, the traction speed is 0.8m / min, the mold pressure is 8MPa and the curing time is 2min.

[0089] (4) Post-processing: Same as in Example 1.

[0090] Comparative Example 1

[0091] The difference from Example 1 is that no organic microcapsule phase change material is added, and the flame-retardant epoxy resin is increased to 72 parts. The remaining components and processes are the same.

[0092] Comparative Example 2

[0093] The difference from Example 1 is that uncoated ordinary paraffin wax with a melting point of 80°C is used instead of the organic microcapsule phase change material. During the mixing in step (1), paraffin wax melts and precipitates, resulting in an uneven resin system; in step (2), a large amount of paraffin wax adheres to the fiber surface in the impregnation tank, making normal pultrusion molding impossible.

[0094] Comparative Example 3

[0095] The difference from Example 1 is that the phase change temperature of the organic microcapsule phase change material is 50°C (latent heat 160 J / g). At an impregnation temperature of 60°C, the microcapsule core material liquefies prematurely, some microcapsules rupture, oily exudate appears on the surface of the pultruded product, and microbubble defects are generated inside.

[0096] Performance testing methods:

[0097] Combustion performance: Cone calorimeter test according to GB / T 16172, radiant heat flux 50kW / m² 2 Calculate the total heat release (THR) and total heat release per unit area, and determine the combustion rating according to GB 8624-2012.

[0098] Tensile strength: Tested according to GB / T 1447.

[0099] Bending strength: Tested according to GB / T 1449.

[0100] Profile density: in accordance with GB / T 1463.

[0101] Smoke density rating (SDR): as per GB / T 8627.

[0102] Melting droplet grade (d) and flue gas toxicity grade (t0): determined according to Appendix D and Appendix E of GB 8624-2012.

[0103] Table 1 Performance test results of the examples and comparative examples

[0104]

[0105] As can be seen from Table 1, the composite materials of all embodiments of the present invention meet the requirements of GB 8624-2012 A2-s1-d0-t0 grade, with a total heat release value per unit area ≤7.5 MJ / m². 2 Simultaneously, it maintained excellent tensile strength (≥650MPa) and flexural strength (≥700MPa). Comparative Example 1, without the addition of organic microcapsule phase change material, showed a significantly increased total heat release, reaching only B1 level, indicating that the latent heat absorption of the phase change material plays a crucial synergistic role in reducing heat release. Comparative Example 2 could not be prepared normally due to the use of uncoated phase change material, demonstrating that inorganic coated microcapsules are a necessary means to achieve process feasibility. Comparative Example 3 used microcapsules with excessively low phase change temperatures, resulting in liquefaction during the impregnation stage, which not only reduced the flame retardant synergy but also impaired mechanical properties. These results demonstrate that this invention, by selecting organic microcapsule phase change materials within a specific parameter range and compounding them with inorganic flame-retardant fillers and synergistic flame retardants, achieves a synergistic improvement in low heat release, high flame retardancy rating, and high mechanical properties in the pultrusion process.

Claims

1. An organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material, characterized in that, It comprises the following components, by weight percentage: 75%~85% reinforcing agent and 15%~25% resin matrix; the resin matrix comprises the following components by weight: 55~65 parts flame retardant resin, 8~15 parts organic microcapsule phase change material, 15~22 parts inorganic flame retardant filler, 2~3 parts synergistic flame retardant, 8~12 parts reactive diluent, 85~95 parts curing agent, 0.4~0.9 parts accelerator, 0.4~0.7 parts coupling agent, and 0.2~0.4 parts internal release agent; The organic microcapsule phase change material is an inorganic-encapsulated organic phase change microcapsule with a phase change temperature of 70~90℃, a latent heat of ≥170J / g, a microcapsule particle size of 10~60μm, and a coating layer thickness of 100~250nm. The combustion performance of the composite material meets the requirements of GB 8624-2012 A2-s1-d0-t0 grade, with a total heat release per unit area ≤7.5 MJ / m². 2 Tensile strength ≥650MPa, flexural strength ≥700MPa, profile density 2100~2200kg / m³ 3 .

2. The composite material according to claim 1, characterized in that, The reinforcement is a continuous fiber reinforcement, selected from one or more of alkali-free glass fiber, carbon fiber, and aramid fiber, with a fiber volume fraction of 70% to 82%, and is laid up using a continuous yarn and felt composite layer or a single continuous yarn layer.

3. The composite material according to claim 1, characterized in that, The flame-retardant resin is a halogen-free flame-retardant thermosetting resin adapted to the pultrusion process, selected from one or more of epoxy resin, phenolic epoxy resin, o-cresol resin, and vinyl ester resin, with a total calorific value of 30.0~38.0 MJ / kg; the reactive diluent is selected from glycidyl ether reactive diluents; the curing agent is selected from one of acid anhydride or amine curing agents; the accelerator is selected from quaternary phosphate salt or tertiary amine accelerators; and the coupling agent is selected from silane coupling agents or titanate coupling agents.

4. The composite material according to claim 1, characterized in that, The resin matrix also includes 0.2 to 0.4 parts of smoke suppressant, which is selected from molybdenum-based and tin-based smoke suppressants; the inorganic flame retardant filler is selected from one or more of aluminum hydroxide and magnesium hydroxide, with a particle size of 1 to 10 μm.

5. The composite material according to claim 1, characterized in that, The coating layer of the organic microcapsule phase change material is selected from one of silica, melamine-formaldehyde resin, and urea-formaldehyde resin; the organic phase change material is selected from one or more of fatty acid-based, paraffin-based, and polyol-based organic phase change materials.

6. The composite material according to claim 1, characterized in that, The synergistic flame retardant is selected from one or more of expandable graphite, nano-montmorillonite, and carbon black.

7. A method for preparing an organic microcapsule phase change synergistic Class A flame-retardant pultruded composite material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Preparation of resin system: Flame retardant resin, organic microcapsule phase change material, inorganic flame retardant filler, synergistic flame retardant, reactive diluent, coupling agent and smoke suppressant are put into a mixing device and mixed for 15-25 min at 20~40℃ and vacuum degree ≤-0.08MPa to obtain component A; curing agent, accelerator and internal release agent are mixed evenly to obtain component B; component A and component B are mixed at a mass ratio of 100:85~95, and the viscosity of the mixed system is controlled to be 600~1500mPa·s; (2) Impregnation and preforming: The continuous fiber reinforcement is impregnated into the resin system prepared in step (1) through an impregnation tank. The impregnation temperature is controlled below the phase change temperature of the organic microcapsule phase change material to avoid premature liquefaction of the organic microcapsule phase change material. Then, the fiber layup is sorted and excess resin is removed through a preforming mold. (3) Pultrusion curing: The preformed fiber-resin composite is fed into the pultrusion mold and multi-stage gradient temperature control is adopted. The mold temperature is 100~120℃, 130~150℃ and 160~180℃ respectively, and the traction speed is 0.2~0.8m / min to achieve continuous curing. (4) Post-processing: Cut and polish the cured profile to obtain the finished product.

8. The preparation method according to claim 7, characterized in that, In step (1), the stirring speed of the mixing equipment is 200~600 r / min; in step (3), the pressure of the pultrusion die is controlled at 8~18 MPa, and the curing time is 2~6 min.

9. The preparation method according to claim 7, characterized in that, In step (2), the fiber impregnation rate is controlled at 75%~95%; in step (4), the finished product cutting accuracy is ±0.5mm, and the surface roughness Ra of the profile after grinding is ≤1.6μm.

10. The application of a composite material as described in any one of claims 1 to 6 in photovoltaic brackets, power poles, building profiles, and pipe gallery structural components.

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