Bio-based phosphorus-containing intrinsic flame-retardant polyurethane composite material track for coal mine

Abstract

The invention discloses a bio-based phosphorus-containing intrinsic flame-retardant polyurethane composite material track for a coal mine, and belongs to the technical field of coal mine robot inspection tracks. The track material is a continuous fiber reinforced flame-retardant antistatic polyurethane composite material, and the flame-retardant antistatic polyurethane composite material is composed of polyurethane resin and glass fibers. The polyurethane resin comprises a component A, a component B, bio-based phosphorus-containing polyol, a flame retardant and an antistatic agent. The preparation method comprises the steps of fiber traction, resin mixing, mold heating curing and cutting forming. Through innovative application and process optimization of the bio-based DOPO derivative, the nonmetal track material which is light in weight, resistant to corrosion, resistant to inflaming, resistant to static electricity and excellent in mechanical property is developed.

Description

Technical Field

[0001] The present invention belongs to the technical fields of inspection tracks for coal mine robots and flame-retardant and antistatic composite materials, and relates to a bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite material track for coal mines. Background Art

[0002] With the progress of coal mining technology and the improvement of intelligent requirements, the mine-mounted inspection robots are more and more widely used in the underground environment. The mine-mounted robots have excellent climbing performance and running stability, can realize 24-hour uninterrupted patrol inspection, integrate personnel safety, environmental monitoring and equipment status detection, and significantly improve the safety and efficiency of coal mine production. Compared with the ground inspection equipment, the mine-mounted robots do not occupy the ground space and are especially suitable for the narrow and complex underground working environment. However, as one of the core components of the inspection robot, the material properties of the track directly determine the operation reliability and service life of the system.

[0003] At present, the commercially available inspection tracks for mine-mounted robots mainly adopt metal materials such as steel or aluminum alloy. These metal tracks have high mechanical strength and durability in the conventional ground environment, but face many challenges in the coal mine underground environment. First, the underground environment has a high humidity all year round, and the air contains corrosive gases such as sulfides and nitrogen oxides, which cause the metal tracks to be prone to electrochemical corrosion, surface rusting or structural weakening, and the service life is greatly shortened compared with the ground environment. Second, the self-weight of the metal track is relatively large, and the transportation, installation and maintenance are difficult. Especially in the case of limited underground space, a large amount of manpower and material resources are required to complete the track laying and replacement, increasing the safety risk and economic cost. Research shows that if lightweight non-metal materials are used to replace the metal track, the self-weight of the track can be reduced to about one-fourth of that of steel, thus significantly reducing the transportation and installation difficulties and improving the construction efficiency.

[0004] In recent years, composite materials have been widely used in aerospace, construction and transportation fields due to their light weight, high strength and corrosion resistance. However, in the underground environment of coal mines, the performance requirements of composite materials are more stringent. There are flammable gases and dust underground, and the track material must have excellent flame retardant properties to prevent fire accidents; at the same time, static electricity accumulation may cause sparks, and antistatic performance is also a key indicator. In addition, as the load-bearing component of the inspection robot, the track needs to have sufficient tensile strength and bending strength to withstand the dynamic load when the robot is running. At present, there are few studies on the application of non-metallic tracks, and existing non-metallic composite materials (such as ordinary polyurethane or epoxy resin-based composite materials) are difficult to fully meet the needs of underground environments in terms of flame retardant and antistatic properties. For example, traditional polyurethane composites usually improve flame retardant properties by adding external flame retardants, but high doses of flame retardants may lead to decreased mechanical properties of the material, increased processing difficulty or increased cost. In addition, antistatic properties usually rely on the addition of conductive fillers, but problems such as uneven dispersion of fillers or performance degradation after long-term use have not been completely solved.

[0005] On the other hand, bio-based materials have attracted attention due to their environmental friendliness and sustainability, but their application research in high-performance flame-retardant and antistatic composite materials is still in its infancy. Existing bio-based composite materials are mostly used in low-requirement scenarios, and it is difficult to meet the comprehensive requirements of flame retardancy, antistatic and mechanical properties in coal mines. In addition, the mechanical properties, safety performance and long-term stability of non-metallic rails still need to be verified through a large number of experiments, and there is a lack of mature industrial application cases. In response to the above problems, the development of a lightweight, corrosion-resistant, flame-retardant and antistatic non-metallic rail material with excellent mechanical properties has become a technical problem that needs to be urgently solved in the field of intelligent coal mine inspection equipment. Summary of the invention

[0006] In view of this, the present invention provides a bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite rail for coal mines. By introducing bio-based phosphorus-containing polyols, combined with continuous fiber reinforcement technology and a specific preparation process, a new type of composite rail is developed to solve the problems of severe corrosion and heavy weight of metal rails and insufficient flame retardant and antistatic properties of non-metallic rails.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A bio-based phosphorus-containing intrinsic flame-retardant polyurethane composite rail for coal mines, the rail material is a continuous fiber reinforced flame-retardant antistatic polyurethane composite material, the flame-retardant antistatic polyurethane composite material is composed of polyurethane resin and glass fiber; the polyurethane resin includes components A and B, wherein component A is diphenylmethane diisocyanate, and component B is a polyol mixed liquid in which polyester polyol, bio-based phosphorus-containing polyol, flame retardant, and antistatic agent are mixed in a set proportion;

[0009] The bio-based phosphorus-containing polyol is of structural formula I: Among R1 to R11, there are 2 to 4 compounds of structural formula II, and the rest are The structural formula II is

[0010]

[0011] Furthermore, the preparation method of the track includes the following steps:

[0012] Step 1: The traction fiber passes through the oven and the yarn splitting board and is drawn into the mold respectively; the traction felt / cloth enters the mold;

[0013] Step 2: Prepare the bio-based phosphorus-containing polyol, and mix it with the polyester polyol, flame retardant, and antistatic agent in proportion to obtain component B, and add components A and B to the two-component resin mixer;

[0014] Step 3: Turn on the mold heating device for 1.5 h to fully heat the mold;

[0015] Step 4: Turn on the oven and start the traction device;

[0016] Step 5: Turn on the glue injection machine and the cutting machine;

[0017] Step 6: The resin and glass fiber are cured through the mold to obtain a flame-retardant and antistatic bio-based phosphorus-containing intrinsically flame-retardant polyurethane profile, which is cut to a fixed length by the cutting machine to obtain a composite material track.

[0018] Furthermore, in step 2, the method for preparing the bio-based phosphorus-containing polyol includes the following steps:

[0019] (1) Add phytic acid and ammonia water to the reaction kettle in sequence, dissolve with water and then heat to 30 - 80 °C, carry out a condensation reflux reaction for 20 - 200 min, and obtain the intermediate of structural formula III after purification and drying;

[0020] (2) Add the compound of structural formula II to the flask equipped with a condensation device, add an organic solvent and heat to 30 °C - 100 °C to dissolve, and at 25 °C - 150 °C, add the intermediate of structural formula III obtained in step (1) and react for 1 h - 10 h, then remove the solvent, and obtain the bio-based phosphorus-containing polyol after drying;

[0021] The structural formula III is Among R13 to R24, there are 2 to 4 H + , and the rest are

[0022] The structural formula II is

[0023] Further, in step (1), the molar ratio of phytic acid to ammonia water is 1:8 - 10.

[0024] Further, in step (2), the organic solvent is any one or more of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chlorobenzene, dichlorobenzene, trichlorobenzene, ethylene glycol methyl ether, ethylene glycol ethyl ether or 1,4-dioxane.

[0025] Further, in step (2), the molar ratio of the compound of structural formula Ⅱ to the intermediate of structural formula Ⅲ is 2 - 4:1.

[0026] Further, in step 3, the heating temperature of the mold: 150°C - 210°C, divided into three zones, the mold temperature at the front end near the yarn inlet is 150°C - 170°C, the middle section is 170°C - 190°C, and the rear section near the outlet of the tubular profile is 190°C - 210°C;

[0027] In step 4, the oven temperature: the oven temperature is 60°C - 150°C, and in step 5, the injection pressure: 0.5 - 1 MPa.

[0028] Further, in step 4, the fiber traction speed: 0.2 - 2 m / min, the fiber cloth angle: [20°, 70°, -20°, -70°] or [10°, 90°, -10°, -90°].

[0029] Further, the cross-sectional shape of the track is in the shape of an I-shaped, triangular, square or T-shaped.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. High-efficiency inherent flame retardancy, preventing the precipitation of flame retardants: The present invention uses bio-based phosphorus-containing polyols. By directly connecting bio-based DOPO derivatives into the polyurethane molecular chain, an inherently flame-retardant and antistatic polyurethane composite material is formed. When this material burns, it can self-crosslink and expand to form a dense carbon layer, and crosslink with the pyrolysis small molecules of the polymer to generate a carbon layer with high thermal stability, effectively isolating oxygen and heat. The flame retardancy can reach UL94 V-0 level and meet the MT113 standard. Compared with traditional additive flame retardants, the inherent flame retardant design eliminates the problem of flame retardant precipitation, significantly improves the flame retardancy efficiency, reduces the dosage of additive flame retardants, improves the mechanical properties of the flame-retardant polyurethane composite material, avoids the problem of precipitation or migration of flame retardants during long-term use, and ensures the long-term stability of the flame retardancy of the material, which is particularly suitable for high fire risk environments in coal mines.

[0032] 2. Excellent mechanical properties, enhancing safety guarantee: Through continuous glass fiber reinforcement technology and chemical bonding of bio-based phosphorus-containing polyols and polyurethane resins, the amount of additive flame retardants is reduced, and the idler central shaft of the present invention has excellent mechanical properties. Tests show that the composite material prepared by the pultrusion process has a tensile strength ≥ 1200 MPa and a flexural strength ≥ 1200 MPa. The introduction of DOPO derivatives reduces or eliminates the use of additive flame retardants, not only enhancing the rigidity of the molecular chain but also improving the overall strength of the composite material, providing a reliable guarantee for the safe operation of inspection robots.

[0033] 3. Lightweight design: The density of the polyurethane composite material is only about one-fourth of that of the steel track, realizing the lightweight design of the track roller. This not only reduces the overall weight of the track, lowers the transportation and installation costs, but also can withstand the dynamic load during the operation of the inspection robot, ensuring the structural stability for long-term use.

[0034] 4. Excellent corrosion resistance: The composite material track can resist the erosion of various corrosive media such as acids, alkalis, and salts, and its corrosion resistance is better than that of metal tracks, especially suitable for the complex and harsh environment underground in coal mines. Its excellent corrosion resistance effectively extends the service life of the track and reduces the maintenance cost.

[0035] 5. Excellent antistatic performance: The synergistic effect of bio-based phosphorus-containing polyols and antistatic agents can make the surface resistivity of the composite material track ≤ 3×10 8 Ω, meeting the MT113 standard, which can effectively prevent static electricity accumulation and reduce the fire risk caused by static sparks. This characteristic significantly improves the safety of the composite material track in the complex environment underground in coal mines.

[0036] 6. Environmental protection and sustainability: The bio-based binary terminal hydroxyl DOPO derivative flame retardant of the present invention adopts a halogen-free and environmentally friendly design. The synthetic monomers (such as phytic acid) are widely sourced and renewable, reducing the carbon footprint in the production process and the dependence on non-renewable resources. Compared with traditional halogen-containing flame retardants, the present invention avoids the generation of toxic gases during combustion, meets the requirements of green manufacturing and sustainable development, and has significant environmental friendliness.

[0037] 7. Process optimization and high production efficiency: By precisely controlling the heating temperatures of the three zones of the mold (150°C - 210°C), the fiber traction speed (0.2 - 2 m / min), and the injection pressure (0.5 - 1 MPa), the present invention optimizes the molding process of continuous fiber-reinforced composites, ensuring uniform infiltration of resin and fiber and curing quality. The scientific design of the fiber cloth angles (such as [20°, 70°, -20°, -70°] or [10°, 90°, -10°, -90°]) further improves the mechanical properties and structural stability of the track. This process is suitable for large-scale production, with good product quality consistency and high production efficiency, laying a foundation for industrial application.

[0038] In summary, through the innovative application of bio-based DOPO derivatives and process optimization, the present invention develops a non-metallic track material that is lightweight, corrosion-resistant, inherently flame-retardant, antistatic, and has excellent mechanical properties, overcoming the defects of metal tracks such as easy corrosion, heavy self-weight, and insufficient performance of traditional non-metallic tracks. This track significantly improves the running safety and efficiency of underground coal mine inspection robots, reduces installation and maintenance costs, and is also environmentally friendly and sustainable, with significant economic and social value.

[0039] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in preferred detail below in conjunction with the drawings, where:

[0041] Figure 1 It is a schematic diagram of the preparation process of the bio-based phosphorus-containing inherently flame-retardant polyurethane composite track for coal mines in the present invention.

[0042] Figure 2 It is a schematic diagram of multiple track structures in the shape of an I-beam.

[0043] Figure 3 It is a schematic diagram of track structures in the shape of a square, T-shape, and triangle. Detailed Description of the Specific Embodiments

[0044] The following describes the implementation modes of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0045] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation on the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which does not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0046] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0047] Please refer to Figures 1 to 3 , a bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite track for coal mines. The track material is a continuous fiber-reinforced flame-retardant and antistatic polyurethane composite. The flame-retardant and antistatic polyurethane composite is composed of polyurethane resin and glass fiber; the polyurethane resin includes components A and B. Among them, component A is diphenylmethane diisocyanate, and component B is a polyol mixture obtained by mixing polyester polyol, bio-based phosphorus-containing polyol, flame retardant, and antistatic agent in a set ratio.

[0048] Among them, component A can be selected from 4,4'-MDI, modified MDI, polymeric MDI (PMDI), etc. for pultrusion; the polyester polyol in component B can be selected from adipic acid-based polyester polyol, phthalic anhydride (PA)-based polyester polyol, hydrolysis-resistant polyester polyol, etc., which are polyols for pultrusion.

[0049] The mixing ratio of the flame retardant and the bio-based phosphorus-containing polyol is determined according to the flame retardant grade requirements. For example, to achieve V0 grade flame retardancy, the mass ratio of the polyester polyol to the bio-based phosphorus-containing polyol is 72:28; to meet the MT113 flame retardant requirement, the mass ratio of the polyester polyol to the bio-based phosphorus-containing polyol is 63:37.

[0050] The antistatic agent can be selected from one or a mixture of 1,3-dimethylimidazolium tetrafluoroborate, N-octylpyridinium bromide, N-butyl-N-methylpiperidinium bromide, N-butyl-N-methylpyrrolidinium bromide, tributylmethylammonium chloride, N-ethyl,methylmorpholinium bromide, and tributylethylphosphonium bromide ionic liquids, as well as carbon fiber, etc. According to the different surface resistances achieved, the dosage of the antistatic agent is different. For example, when the surface resistance reaches 10 9 Ω, the mass ratio of the polyol mixture to the antistatic agent is 72:28; when the surface resistance reaches 10 8 Ω, the mass ratio of the polyol mixture to the antistatic agent is 65:35; when the surface resistance < 10 8 Ω, carbon fiber is used on the surface.

[0051] Among them, the bio-based phosphorus-containing polyol has the structural formula I: Among R1 to R11, there are 2 to 4 compounds with the structural formula II, and the rest are The structural formula II is

[0052]

[0053] The preparation method of the track includes the following steps:

[0054] Step 1: The traction fiber passes through the oven and the yarn dividing plate and is drawn into the mold respectively; the traction felt / cloth enters the mold;

[0055] Step 2: Prepare the bio-based phosphorus-containing polyol, and mix it with the polyester polyol, flame retardant, antistatic agent, etc. in proportion to obtain the B component, and add the A and B components to the two-component resin mixer;

[0056] Step 3: Turn on the mold heating device for 1.5 h to fully heat the mold; the mold heating temperature is 150°C - 210°C, divided into three zones. The mold temperature at the front end near the yarn inlet is 150°C - 170°C, the middle section is 170°C - 190°C, and the rear section near the outlet of the tubular profile is 190°C - 210°C.

[0057] Step 4: Turn on the oven, the oven temperature is 60°C - 150°C; start the traction device, the fiber traction speed is 0.2 - 2 m / min, and the fiber cloth angle is [20°, 70°, -20°, -70°] or [10°, 90°, -10°, -90°];

[0058] Step 5: Turn on the glue injector and the cutting machine. Glue injection pressure: 0.5 - 1 MPa;

[0059] Step 6: The resin and glass fiber are cured in a mold to obtain a flame-retardant and antistatic bio-based phosphorus-containing intumescent polyurethane profile, which is cut to a fixed length by a cutting machine to obtain a composite track.

[0060] Among them, in Step 2, the method for preparing the bio-based phosphorus-containing polyol includes the following steps:

[0061] (1) Add phytic acid and ammonia water to the reaction kettle in sequence. The molar ratio of phytic acid to ammonia water is 1:8 - 10. After adding water to dissolve, heat to 30 - 80 °C, carry out condensation reflux reaction for 20 - 200 min, and obtain the intermediate of Structural Formula III after purification and drying;

[0062] (2) Add the compound of Structural Formula II to a flask equipped with a condensation device, add an organic solvent and heat to 30 °C - 100 °C to dissolve. At 25 °C - 150 °C, add the intermediate of Structural Formula III obtained in step (1) and react for 1 h - 10 h, then remove the solvent. After drying, the bio-based phosphorus-containing polyol can be obtained. The organic solvent used can be any one or several of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chlorobenzene, dichlorobenzene, trichlorobenzene, ethylene glycol methyl ether, ethylene glycol ethyl ether or 1,4-dioxane.

[0063] Structural Formula III is wherein R13 - R24 contain 2 - 4 H + , and the rest are

[0064] Structural Formula II is In step (2), the molar ratio of the compound of Structural Formula II to the intermediate of Structural Formula III is 2 - 4:1.

[0065] The cross-sectional shape of the track in the present invention can be various, such as I-shaped, triangular, square or T-shaped.

[0066] In the following examples, Component A used is 4,4'-MDI, the polyester polyol in Component B is adipic acid-based polyester polyol, the flame retardant is aluminum hydroxide, and the antistatic agent is 1,3-dimethylimidazolium tetrafluoroborate.

[0067] Example 1 (basic formula)

[0068] Formulation: polyester polyol 24.2 phr, bio-based phosphorus-containing polyol 15.4 phr, antistatic agent 15.4 phr; MDI: 45 phr; pultruded glass fiber: 80 wt%, fiber cloth laying angle [20°, 70°, -20°, -70°].

[0069] Process parameters: pultrusion speed 0.5 m / min, die temperature at the front section 160 °C, middle section 180 °C, rear section 190 °C, injection pressure 0.8 MPa.

[0070] Example 2 (high flame retardant formula)

[0071] Formulation: polyester polyol 14.6 phr, bio-based phosphorus-containing polyol 20.4 phr, antistatic agent 20 phr; MDI: 45 phr; pultruded glass fiber: 80 wt%, fiber cloth lay-up angles [20°, 70°, -20°, -70°].

[0072] Process parameters: pultrusion speed 0.5 m / min, die temperature at the front section 160 °C, middle section 180 °C, rear section 190 °C, injection pressure 0.8 MPa.

[0073] Example 3

[0074] Formulation: polyester polyol 16.6 phr, bio-based phosphorus-containing polyol 13 phr, liquid flame retardant 10 phr, antistatic agent 15.4 phr; MDI: 45 phr; pultruded glass fiber: 80 wt%, fiber cloth lay-up angles [20°, 70°, -20°, -70°].

[0075] Process parameters: pultrusion speed 0.5 m / min, die temperature at the front section 160 °C, middle section 180 °C, rear section 190 °C, injection pressure 0.8 MPa.

[0076] Example 4

[0077] Formulation: polyester polyol 34.6 phr, bio-based phosphorus-containing polyol 20.4 phr, antistatic agent surface carbon fiber; MDI: 45 phr; pultruded glass fiber: 80 wt%, fiber cloth lay-up angles [20°, 70°, -20°, -70°].

[0078] Process parameters: pultrusion speed 0.5 m / min, die temperature at the front section 160 °C, middle section 180 °C, rear section 190 °C, injection pressure 0.8 MPa.

[0079] Comparative Example 1 (omitting phosphorus-containing polyol)

[0080] Formulation: polyester polyol 55 phr, MDI: 45 phr; pultruded glass fiber: 80 wt%, fiber cloth lay-up angles [20°, 70°, -20°, -70°].

[0081] Process parameters: pultrusion speed 0.5 m / min, die temperature at the front section 160 °C, middle section 180 °C, rear section 190 °C, injection pressure 0.8 MPa.

[0082] Comparative Example 2

[0083] Formulation: 14.6 phr of polyester polyol, 25 phr of liquid flame retardant, 15.4 phr of antistatic agent; MDI: 45 phr; Pulled glass fiber: 80 wt%, fiber cloth laying angle [0°, ±45°, 90°].

[0084] Process parameters: Pulling speed 0.5 m / min, die temperature at the front stage 160 °C, middle stage 180 °C, rear stage 190 °C, injection pressure 0.8 MPa.

[0085] The products made in the above examples were tested, and the test results are shown in the following table:

[0086]

[0087] Note: From the comparison results, it can be seen that due to the participation of bio-based phosphorus-containing polyol in the reaction and the ability to achieve the flame retardant effect, the mechanical properties of the composite material prepared using the mixture of bio-based phosphorus-containing polyol and polyol are slightly reduced, and the flame retardant and antistatic properties can meet the requirements of MT113 (surface resistance ≤ 3×10 8 Ω), as shown in Example 2; while reducing the dosage of bio-based phosphorus-containing polyol and antistatic agent can make the flame retardancy reach V0 and the surface resistance reach 3.8×10 9 Ω, and the mechanical properties are excellent; due to the relatively high price of bio-based phosphorus-containing polyol, using a mixture of bio-based phosphorus-containing polyol and liquid flame retardant or completely using liquid flame retardant to prepare the composite material to reduce costs will reduce the mechanical properties of the composite material, such as Example 3 and Comparative Example 2; to further reduce the surface resistance of the composite material profile, using carbon fiber on the surface of the composite material can make the surface resistance ≤ 10 3 Ω, and the mechanical properties are almost the same as those of the non-flame retardant and antistatic composite material, such as Example 4.

[0088] The laying angle (angle with the axis) of the fiber cloth will affect the tensile strength and impact strength of the structure. The influencing method is that the double laying angle is inversely proportional to the axial tensile strength and directly proportional to the impact strength. To balance the tensile strength and impact strength, a small-angle bionic double laying angle can be used.

[0089] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A bio-based phosphorus-containing inherently flame-retardant polyurethane composite track for coal mines, characterized in that: The track material is a continuous fiber-reinforced flame-retardant and antistatic polyurethane composite material, and the flame-retardant and antistatic polyurethane composite material is composed of polyurethane resin and glass fiber; the polyurethane resin includes components A and B. Among them, component A is diphenylmethane diisocyanate, and component B is a polyol mixture obtained by mixing polyester polyol, bio-based phosphorus-containing polyol, flame retardant, and antistatic agent in a set ratio; The bio-based phosphorus-containing polyol is of structural formula I: Among R1 to R11, there are 2 to 4 compounds of structural formula II, and the rest are The structural formula II is 2. The bio-based phosphorus-containing inherently flame-retardant polyurethane composite track for coal mines according to claim 1, wherein, The preparation method of the track includes the following steps: Step 1: The traction fibers pass through an oven and a yarn dividing plate and are drawn into a mold respectively; the traction felt / cloth enters the mold; Step 2: Prepare the bio-based phosphorus-containing polyol, and mix it with polyester polyol, flame retardant, and antistatic agent in proportion to obtain component B, and add components A and B to a two-component resin mixer; Step 3: Turn on the mold heating device for 1.5 h to fully heat the mold; Step 4: Turn on the oven and start the traction device; Step 5: Turn on the injection molding machine and the cutting machine; Step 6: The resin and glass fiber are cured through the mold to obtain a flame-retardant and antistatic bio-based phosphorus-containing inherently flame-retardant polyurethane profile, and it is cut to a fixed length by a cutting machine to obtain a composite material track.

3. The bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite track for coal mines according to claim 2, wherein, In step 2, the method for preparing the bio-based phosphorus-containing polyol includes the following steps: (1) Add phytic acid and ammonia water to a reaction kettle in sequence, dissolve with water and then heat to 30 - 80 °C, carry out condensation reflux reaction for 20 - 200 min, and obtain the intermediate of structural formula III after purification and drying; (2) Add the compound of structural formula II to a flask equipped with a condensation device, add an organic solvent and heat to 30 °C - 100 °C to dissolve, and at 25 °C - 150 °C, add the intermediate of structural formula III obtained in step (1) and react for 1 h - 10 h, then remove the solvent, and obtain the bio-based phosphorus-containing polyol after drying; The structural formula Ⅲ is wherein among R13 to R24, there are 2 to 4 H + , and the rest are The structural formula II is 4. The bio-based phosphorus-containing inherently flame-retardant polyurethane composite track for coal mines according to claim 3, wherein: In step (1), the molar ratio of phytic acid to ammonia water is 1:8 - 10.

5. The bio-based phosphorus-containing inherently flame-retardant polyurethane composite track for coal mines according to claim 3, wherein In step (2), the organic solvent is any one or several of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chlorobenzene, dichlorobenzene, trichlorobenzene, ethylene glycol methyl ether, ethylene glycol ethyl ether, or 1,4-dioxane.

6. The bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite track for coal mines according to claim 3, wherein: In step (2), the molar ratio of the compound of structural formula II to the intermediate of structural formula III is 2 - 4:

1.

7. The track made of the bio-based phosphorus-containing inherently flame-retardant polyurethane composite material for coal mines according to claim 2, characterized in that: In step 3, the mold heating temperature: 150 °C - 210 °C, divided into three zones, the mold temperature at the front end of the mold near the yarn inlet is 150 °C - 170 °C, the middle section is 170 °C - 190 °C, and the rear section near the tube-shaped profile outlet is 190 °C - 210 °C; In step 4, the oven temperature: the oven temperature is 60 °C - 150 °C, and in step 5, the injection pressure: 0.5 - 1 MPa.

8. The bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite track for coal mines according to claim 2, characterized in that: In step 4, the fiber traction speed: 0.2 - 2 m / min, the fiber cloth angle: [20°, 70°, -20°, -70°] or [10°, 90°, -10°, -90°].

9. The bio-based phosphorus-containing intrinsically flame-retardant polyurethane composite track for coal mines according to claim 1, wherein: The cross-sectional shape of the track is in the shape of an I-shaped, triangular, square, or T-shaped.

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