Polyurethane-liquid-filled blast protection structure

Abstract

The present application relates to a kind of polyurethane-liquid filled explosion protection structure, belong to public safety defense equipment technical field.It includes flexible shell, polyurethane foam ball and liquid;Polyurethane foam ball and liquid are filled in flexible shell, column explosive is located at the center of flexible shell, detonator one end is inserted on explosive, and the other end extends to the outside of flexible shell.By selecting the polyurethane of appropriate density and liquid, and controlling the volume ratio of both, fill in flexible shell;Explosive is located at the center of shell, can effectively isolate oxygen, reduce the secondary energy release generated by explosion, reduce explosion reaction degree and its aftereffect reaction;While polyurethane and liquid cooperate to form the flexible protection structure of multiple cavities, effectively improve the energy absorption density of structure in unit protection volume, and energy absorption efficiency is high.

Description

Technical Field

[0001] This invention relates to a polyurethane-liquid-filled explosion protection structure, belonging to the field of public safety protection equipment technology. Background Technology

[0002] Current protective structures, such as explosion-proof containers and explosion-proof spheres, are generally made of materials such as metal steel, ceramics, and aluminum alloys, with a diameter typically ranging from 0.4m to 1.2m. During disposal, the explosive is placed inside the explosion-proof container structure at a certain distance from the protective structure wall. Generally speaking, the farther the rigid protective structure wall is from the explosion center, the less likely it is to break apart. This wastes a lot of protective space and greatly increases the weight of the protective structure. If the explosive is placed directly close to the rigid protective structure wall, it will cause the structure to break and scatter, resulting in injury.

[0003] Polyurethane foam is a type of polymer containing a three-dimensional network structure. Due to its advantages such as low density, high specific strength, and low cost, it is widely used in impact-resistant protective structures. Compared to traditional high-strength, dense, and explosion-proof materials, polyurethane foam is lightweight, causes no secondary damage after an explosion, and has high design flexibility in its microstructure, making it a promising area for research in explosion-proof structure design.

[0004] Patent ZL202111123230.3 discloses an explosion-proof and impact-resistant structure based on flexible spheres and a method for preparing such flexible spheres. The flexible spheres are mainly filled within annular wall structures such as flexible explosion-proof barrels, with water as the primary filling liquid, thus achieving shock wave absorption. The protective structure does not directly contact the explosive and is located at a certain distance from the explosion center. Patent ZL202210110946.8 discloses an intrinsically safe explosive disposal and protection device and its usage method. This device fills a layer of explosion-proof filling material on a support plate inside an explosion-proof barrel with polyurethane foam spheres. The filling liquid is also water, dry water, or a shear-thickening liquid. The material itself also does not directly contact the explosive. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a polyurethane-liquid-filled explosion protection structure.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] A polyurethane-liquid-filled explosion protection structure includes a flexible shell, polyurethane foam balls, and a liquid; the polyurethane foam balls and the liquid are filled inside the flexible shell, and the density of the polyurethane foam balls is 100–300 kg / m³. 3 The density of the liquid is 1550–1650 kg / m³. 3The volume of polyurethane foam balls inside the flexible shell is 30% to 70%, and the volume of liquid is 30% to 70%. The explosive is located at the center of the flexible shell, with one end of the detonator inserted into the explosive and the other end extending outside the flexible shell.

[0008] Preferably, the liquid contains nanoporous particles; more preferably, the nanoporous particles include sodium bicarbonate and zeolite; the mass ratio of nanoporous particles to liquid is 1:100 to 5:100.

[0009] Preferably, the flexible shell is a sphere or a cylinder, and the diameter of the flexible shell is 5 to 10 times the diameter of the explosive.

[0010] Preferably, the density of the flexible shell is 1000–2000 kg / m³. 3 More preferably, the flexible shell is made of thermoplastic polyurethane conformal material (TPU) or polyvinyl chloride (PVC); the flexible shell contains fiber fabric as a reinforcing structure.

[0011] Preferably, the thickness of the flexible shell is 0.2 to 2 mm.

[0012] Preferably, the liquid is perfluorohexanone.

[0013] Preferably, the volume percentage of polyurethane foam balls inside the flexible shell is 40% to 50%, and the volume percentage of liquid is 50% to 60%.

[0014] Preferably, the diameter of the polyurethane foam ball is 0.2 to 2 times the diameter of the explosive; more preferably, the diameter of the polyurethane foam ball is the same as the diameter of the explosive.

[0015] Preferably, the polyurethane foam balls are obtained by curing and molding components A and B; component A is composed of the following components in parts by mass: 100 parts of high-functionality, high-hydroxyl-value polyether polyol, 2-5 parts of crosslinking agent, 0.5-2 parts of chemical foaming agent, 5-20 parts of physical foaming agent, 0.2-2 parts of foam stabilizer, 0.5-2 parts of catalyst, 20-50 parts of inorganic nanoparticle material, and 8-12 parts of flame retardant; component B is polyphenylmethane polyisocyanate (PAPI); the molar ratio of -OH groups in component A to -NCO groups in component B is 1.2-1.5:1.

[0016] Preferably, the high-functionality, high-hydroxyl-value polyether polyol has a functionality greater than or equal to 4 and a hydroxyl value of 400–500 mg KOH / g; the crosslinking agent is one or more of triethanolamine, dimethylenetriamine, and trimethylenetetramine; the chemical blowing agent is H₂O; the physical blowing agent is chloroform, dichlorodifluoroethane, n-pentane, or cyclopentane; the foam stabilizer is AK-8805 or AK-8806 from Jiangsu Meiside Company; the catalyst… The catalyst is one or more of A33 (a liquid catalyst containing 33% triethylenediamine), T12 (dibutyltin dihexylsilicate), PC-41 (tris(dimethylaminopropyl)hexahydrotriazine) and DMP30 (2,4,6-tris(dimethylaminomethyl)phenol); the inorganic nanopowder material is one or more of nano-aluminum hydroxide with a particle size of 20-100 nm, nano-magnesium hydroxide with a particle size of 20-100 nm, and nano-calcium carbonate; the flame retardant is expandable graphite.

[0017] Preferably, the high-functionality, high-hydroxyl-value polyether polyol is one or more of 8010, 4110, 8205, and 8305; the crosslinking agent is triethanolamine; the physical foaming agent is chloroform or dichlorofluoroethane; the foam stabilizer is AK-8805 from Jiangsu Meiside Company; the catalyst is a mixture of A33, T12, and DMP30; and the inorganic nanopowder material is nano-aluminum hydroxide with a particle size of 20-30 nm.

[0018] Preferably, the preparation method of the polyurethane foam balls includes the following steps:

[0019] (1) Mix high-functionality, high-hydroxyl-value polyether polyol, crosslinking agent, chemical foaming agent, physical foaming agent, foam stabilizer, catalyst, inorganic nanoparticles and flame retardant evenly to obtain component A;

[0020] (2) Mix components A and B and pour the mixture into a mold. Foam and cure to obtain polyurethane foam balls.

[0021] Beneficial effects

[0022] This invention provides a polyurethane-liquid-filled explosion protection structure. By selecting polyurethane and liquid of appropriate density and controlling their volume ratio, the mixture is filled into a flexible shell. The explosive is located at the center of the shell, which can effectively isolate oxygen, reduce the secondary energy release generated by the explosion, and reduce the degree of explosion reaction and its aftereffects. At the same time, the polyurethane and liquid work together to form a multi-cavity flexible protection structure, which effectively improves the structural energy absorption density per unit protection volume, resulting in high energy absorption efficiency and low secondary damage from the explosion. In addition, the different wave impedance structures formed inside the protection structure can more efficiently cause the shock wave to undergo multiple reflections and refractions inside the protection structure, thereby consuming and absorbing the shock wave energy. Attached Figure Description

[0023] Figure 1-2 This is a schematic diagram of the protective structure described in this invention.

[0024] 1-Explosive; 2-Polyurethane foam spheres; 3-Liquid; 4-Flexible shell;

[0025] Figure 3 These are high-speed photographs taken during the explosions in Example 1 and the comparative example.

[0026] Figure 4 This is a comparison diagram of the flame duration in Example 1 and the comparative example.

[0027] Figure 5 This is a comparison diagram of the peak values ​​of the shock waves in Example 1 and the comparative example. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to specific embodiments.

[0029] like Figure 1-2 As shown, a polyurethane-liquid-filled explosion protection structure includes a flexible shell 4, polyurethane foam balls 2, and liquid 3; the polyurethane foam balls 2 and liquid 3 are filled inside the flexible shell 4, and the density of the polyurethane foam balls 2 is 100-300 kg / m³. 3 The density of liquid 3 is 1550–1650 kg / m³. 3 The volume of polyurethane foam balls 2 inside the flexible shell 4 is 30% to 70%, and the volume of liquid is 30% to 70%. The cylindrical explosive 1 is located at the center of the flexible shell 4, with one end of the detonator inserted into the explosive 1 and the other end extending outside the flexible shell 4.

[0030] Preferably, the liquid contains nanoporous particles; more preferably, the nanoporous particles include sodium bicarbonate and zeolite; the mass ratio of nanoporous particles to liquid is 1:100 to 5:100.

[0031] Preferably, the flexible shell 4 is a sphere or cylinder, and the diameter of the flexible shell is 5 to 10 times the diameter of the explosive.

[0032] Preferably, the density of the flexible shell 4 is 1000–2000 kg / m³. 3 More preferably, the flexible shell 4 is made of thermoplastic polyurethane conformal material (TPU) or polyvinyl chloride (PVC); the flexible shell contains fiber fabric as a reinforcing structure.

[0033] Preferably, the thickness of the flexible shell 4 is 0.2 to 2 mm.

[0034] Preferably, the volume percentage of polyurethane foam balls inside the flexible shell is 40% to 50%, and the volume percentage of liquid is 50% to 60%.

[0035] Preferably, the liquid 3 is perfluorohexanone.

[0036] Preferably, the diameter of the polyurethane foam ball 2 is 0.2 to 2 times the diameter of the explosive 1; more preferably, the diameter of the polyurethane foam ball 2 is the same as the diameter of the explosive 1.

[0037] The polyurethane foam ball 2 is obtained by curing and molding component A and component B. Component A is composed of the following components in parts by mass: 100 parts of high-functionality, high-hydroxyl-value polyether polyol, 2-5 parts of crosslinking agent, 0.5-2 parts of chemical foaming agent, 5-20 parts of physical foaming agent, 0.2-2 parts of foam stabilizer, 0.5-2 parts of catalyst, 20-50 parts of inorganic nanoparticle material, and 8-12 parts of flame retardant. Component B is polyphenylmethane polyisocyanate (PAPI). The molar ratio of -OH groups in component A to -NCO groups in component B is 1.2-1.5:1. The polyurethane foam balls described herein are produced by reacting high-functionality, low-molecular-weight polyether polyols and high-functionality crosslinking agents with an excess of polymeric MDI curing agent, using H2O as a chemical foaming agent. This process increases the crosslinking point density of the resulting polyurethane foam matrix and enhances its hardness and brittleness through the formation of isocyanate trimers and urea-based rigid structures. Furthermore, the addition of a certain amount of inorganic nanoparticles further improves the strength and brittleness of the polyurethane foam. Adding a certain amount of flame retardant can improve the overall flame retardant effect. The raw materials required for preparing easily pulverized polyurethane foam are weighed and mixed uniformly according to a specified ratio, then poured into a mold for foaming and curing to obtain an easily pulverized rigid polyurethane foam structure suitable for explosive shock waves.

[0038] The high-functionality, high-hydroxyl-value polyether polyol has a functionality of 4 or higher and a hydroxyl value of 400–500 mg KOH / g. Examples include high-hydroxyl-value polyether polyols with a functionality of 4 or higher, produced using small molecules containing 4 or more active hydrogen atoms as initiators, such as sucrose, sorbitol, diethylenetriamine, and triethylenetetramine, such as polyether polyols with grades 8010, 4110, 8205, and 8305. Preferred polyether polyols are those with a functionality greater than 4 and a hydroxyl value in the range of 400–500 mg KOH / g, using sucrose or sorbitol as initiators; grades 8010 and 4110 are suitable choices.

[0039] The crosslinking agent is one or more small molecule compounds containing three or more active hydrogen atoms, such as triethanolamine, dimethylenetriamine, and trimethylenetetramine; preferably triethanolamine.

[0040] The chemical foaming agent is H2O.

[0041] The physical foaming agent is chloroform, dichlorodifluoroethane, n-pentane, or cyclopentane; preferably chloroform or dichlorodifluoroethane.

[0042] The foam stabilizer is a foam stabilizer with the brand name AK-8805 or AK-8806 from Jiangsu Meiside Company; preferably, it is a foam stabilizer with the brand name AK-8805 from Jiangsu Meiside Company.

[0043] The catalyst is one or more of A33 (a liquid catalyst containing 33% triethylenediamine), T12 (dibutyltin dihexylsilicate), PC-41 (tris(dimethylaminopropyl)hexahydrotriazine) and DMP30 (2,4,6-tris(dimethylaminomethyl)phenol); preferably a mixture of A33, T12 and DMP30.

[0044] The inorganic nanopowder material is one or more of nano-aluminum hydroxide with a particle size of 20-100 nm, nano-magnesium hydroxide with a particle size of 20-100 nm, and nano-calcium carbonate; preferably, it is nano-aluminum hydroxide with a particle size of 20-30 nm.

[0045] The flame retardant is expandable graphite. A high-temperature heat source induces its rapid expansion, and the highly expanded graphite flakes occupy the surface of the polyurethane, forming a dense carbon barrier layer that covers the combustion zone, isolating the substrate from the external flame. This effectively separates oxygen from the burning substrate, thereby improving the flame retardant performance.

[0046] The preparation method of the polyurethane foam ball 2 includes the following steps:

[0047] (1) Mix high-functionality, high-hydroxyl-value polyether polyol, crosslinking agent, chemical foaming agent, physical foaming agent, foam stabilizer, catalyst, inorganic nanoparticles and flame retardant evenly to obtain component A;

[0048] (2) Mix components A and B and pour the mixture into a mold. Foam and cure to obtain polyurethane foam balls.

[0049] Example 1

[0050] Taking 80g TNT explosive protection as an example, the explosive is a cylindrical explosive with a diameter of φ40*40mm. The flexible shell is made of TPU material with a thickness of 0.3mm, and internal fiber fabric is added for structural reinforcement. The dimensions of the flexible shell are φ200*200mm. 694 polyurethane foam balls with a diameter of 20mm are used as filling, and the weight of the liquid perfluoroethyl ketone is 2002g. The explosive is placed in the center of the flexible shell, the polyurethane foam balls are poured in, and then perfluoroethyl ketone is filled in.

[0051] Polyurethane foam balls are formed by curing components A and B, with a density of 200 kg / m³. 3 The components and mass fractions of component A are as follows: 100 parts of high-functionality, high-hydroxyl-value polyether polyols (brand names 8010 and 4110), 3 parts of crosslinking agent triethanolamine, 1 part of chemical foaming agent H2O, 10 parts of physical foaming agents (chloroform monofluoromethane and dichlorofluoroethane), 0.5 parts of foam stabilizer (AK-8805 foam stabilizer from Jiangsu Meiside Company), 1 part of catalyst (a mixture of A33, T12, and DMP30), 30 parts of inorganic nanopowder material (nano-aluminum hydroxide with a particle size of 30 nm), and 10 parts of flame retardant expandable graphite; component B is polyphenylmethane polyisocyanate PAPI (polymeric MDI with brand name PM200); the molar ratio of -OH groups in component A to -NCO groups in component B is 1.4:1 (the mass ratio of component A to component B is 1:1).

[0052] Comparative Example 1

[0053] No protective structure is used in this comparative example; the explosion is carried out directly in the air.

[0054] Comparative Example 2

[0055] In this comparative example, the protective structure is filled only with polyurethane foam balls, and no liquid is used.

[0056] Both the examples and comparative examples used No. 8 electric detonators for detonation, employed high-speed photography at a frame rate of 10000fps to capture the duration of the flames, and used a pressure sensor located 1m from the explosion center to test the pressure conditions after the explosion.

[0057] High-speed photographs of the explosions in the embodiments and comparative examples are shown below. Figure 3 As shown.

[0058] The results of comparing the flame duration in Example 1 and the comparative example are as follows: Figure 4 As shown, the flame duration under airburst conditions in Comparative Example 1 was 86 ms, in Comparative Example 2 it was 2 ms, while in Example 1 there was almost no flame.

[0059] The peak shock wave pressure at 1m after the explosion was tested. The results of the peak shock wave pressure in the example and comparative examples are as follows: Figure 5 As shown, the maximum peak shock wave pressure after the explosion in Comparative Example 1 was 133.5 kPa, the maximum in Comparative Example 2 was 72.5 kPa, and the maximum peak shock wave pressure in Example 1 was 29.8 kPa.

[0060] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A polyurethane-liquid-filled explosion protection structure, characterized in that: It consists of a flexible shell, polyurethane foam balls, and a liquid; the polyurethane foam balls and liquid are filled inside the flexible shell, and the density of the polyurethane foam balls is 100~300 kg / m³. 3 The density of the liquid is 1550~1650 kg / m³. 3 The volume of polyurethane foam balls inside the flexible shell accounts for 30% to 70%, and the volume of liquid accounts for 30% to 70%. The cylindrical explosive is located at the center of the flexible shell, with one end of the detonator inserted into the explosive and the other end extending outside the flexible shell. The polyurethane foam balls are obtained by curing and molding components A and B. Component A is composed of the following parts by mass: 100 parts of high-functionality, high-hydroxyl-value polyether polyol, 2-5 parts of crosslinking agent, 0.5-2 parts of chemical foaming agent, 5-20 parts of physical foaming agent, 0.2-2 parts of foam stabilizer, 0.5-2 parts of catalyst, 20-50 parts of inorganic nanoparticle material, and 8-12 parts of flame retardant. Component B is polyphenylmethane polyisocyanate. The molar ratio of -OH groups in component A to -NCO groups in component B is 1.2-1.5:

1.

2. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The liquid contains nanoporous particles.

3. The polyurethane-liquid-filled explosion protection structure as described in claim 2, characterized in that: The nanoporous particles include sodium bicarbonate and zeolite; the mass ratio of nanoporous particles to liquid is 1:100 to 5:

100.

4. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The flexible shell is a sphere or cylinder, and its diameter is 5 to 10 times the diameter of the explosive.

5. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The density of the flexible shell is 1000~2000 kg / m³. 3 The flexible shell is made of thermoplastic polyurethane elastomer or polyvinyl chloride; the flexible shell contains fiber fabric as a reinforcing structure. The thickness of the flexible shell (4) is 0.2~2mm.

6. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The liquid is perfluorohexanone.

7. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The volume percentage of polyurethane foam balls inside the flexible shell is 40% to 50%, and the volume percentage of liquid is 50% to 60%.

8. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The diameter of the polyurethane foam ball is 0.2 to 2 times the diameter of the explosive.

9. The polyurethane-liquid-filled explosion protection structure as described in claim 8, characterized in that: The diameter of the polyurethane foam ball is the same as the diameter of the explosive.

10. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The high-functionality, high-hydroxyl-value polyether polyol has a functionality greater than or equal to 4 and a hydroxyl value of 400-500 mgKOH / g; the crosslinking agent is one or more of triethanolamine, dimethylenetriamine, and trimethylenetetramine; the chemical foaming agent is H2O; the physical foaming agent is chloroform, dichlorodifluoroethane, n-pentane, or cyclopentane; the foam stabilizer is AK-8805 or AK-8806 from Jiangsu Meiside Company; the catalyst is one or more of A33, T12, PC-41, and DMP30; the inorganic nanopowder material is one or more of nano-aluminum hydroxide with a particle size of 20-100 nm, nano-magnesium hydroxide with a particle size of 20-100 nm, and nano-calcium carbonate; and the flame retardant is expandable graphite.

11. The polyurethane-liquid-filled explosion protection structure as described in claim 10, characterized in that: The high-functionality, high-hydroxyl-value polyether polyol is one or more of the grades 8010, 4110, 8205, and 8305; the crosslinking agent is triethanolamine; the physical foaming agent is chloroform or dichlorofluoroethane; the foam stabilizer is AK-8805 foam stabilizer from Jiangsu Meiside Company; the catalyst is a mixture of A33, T12, and DMP30; and the inorganic nanopowder material is nano-aluminum hydroxide with a particle size of 20-30 nm.

12. The polyurethane-liquid-filled explosion protection structure as described in claim 1, characterized in that: The preparation method of the polyurethane foam balls includes the following steps: (1) Mix high-functionality, high-hydroxyl-value polyether polyol, crosslinking agent, chemical foaming agent, physical foaming agent, foam stabilizer, catalyst, inorganic nanoparticles and flame retardant evenly to obtain component A; (2) Mix component A and component B and pour into a mold, foam, and cure to obtain polyurethane foam balls.

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