Strain rate sensitive and cold and hot comfort phase change lining for bulletproof helmet

Abstract

The invention provides a strain rate sensitive and cold and hot comfort phase change lining for a bulletproof helmet, the strain rate sensitive and cold and hot comfort phase change lining comprises at least one layer of strain rate sensitive-phase change composite material, and the strain rate sensitive-phase change composite material comprises a strain rate sensitive matrix; the phase change microcapsules are dispersed in the strain rate sensitive type matrix, each phase change microcapsule is of a core-shell structure, and a capsule shell is made of melamine formaldehyde resin; the strain rate sensitive matrix is connected with the phase change microcapsule through a silane coupling agent. According to the strain rate sensitive and cold and hot comfort phase change lining, the dynamic protection performance of the strain rate sensitive material and the intelligent temperature adjusting function of the phase change material are combined, and unification of safety and comfort is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of protective equipment materials, and particularly relates to a strain rate sensitive and cold-heat comfort phase change lining for a bulletproof helmet. BACKGROUND

[0002] The bulletproof helmet is the key equipment in the individual protection system, and is mainly used for protecting the head from the damage of fragments, bullets and the like. The traditional bulletproof helmet lining is mostly made of passive cushioning materials such as foamed plastic, sponge and fabric, and its main function is to absorb impact energy and improve wearing comfort. However, the lining in the prior art has obvious deficiencies: 1. Contradiction between protection and comfort: high-performance cushioning materials are usually thick and poor in air permeability, resulting in stuffiness and sweat in the helmet, which seriously affects the comfort and combat effectiveness during long-time wearing. And the materials focusing on comfort are usually difficult to provide sufficient protection under high-speed impact.

[0003] 2. Single function: the traditional lining material usually only has a single cushioning function, and cannot cope with complex and variable environmental temperature and use scenarios. In a high-temperature environment, the heat accumulated in the head cannot be effectively dissipated; in a low-temperature environment, the inside of the helmet is cold.

[0004] 3. Passive response: the cushioning performance of the traditional foamed material is fixed, and cannot make the optimal energy absorption response according to the change of impact speed, which is easy to cause blunt injury to the soldier's head.

[0005] In recent years, although strain rate sensitive materials such as shear stiffening gel (SSG) have appeared, which can significantly improve the impact resistance when used in protective equipment, they cannot solve the problem of heat dissipation and sweat. Phase change materials (PCM) are used for temperature regulation in textiles, but they are rarely combined with high-performance protective materials, and cannot meet the core requirements of impact protection of protective equipment. Therefore, there is an urgent need for a new type of helmet lining material that can simultaneously consider high-speed impact protection performance and daily wearing heat and moisture comfort. SUMMARY

[0006] In order to solve the problems in the prior art, the present application provides a strain rate sensitive and cold-heat comfort phase change lining for a bulletproof helmet, which combines the dynamic protection performance of the strain rate sensitive material with the intelligent temperature regulation function of the phase change material, and realizes the unity of safety and comfort.

[0007] The technical problem of the present application is solved by adopting the following technical scheme: The first object of the present application is to provide a strain rate sensitive and cold-heat comfort phase change lining for a bulletproof helmet, which comprises at least one layer of strain rate sensitive-phase change composite material, and the strain rate sensitive-phase change composite material comprises: a strain rate sensitive matrix; And a plurality of phase change microcapsules dispersed in the strain rate sensitive matrix, wherein the phase change microcapsules have a core-shell structure and the shell is melamine-formaldehyde resin; The strain rate-sensitive matrix and the phase change microcapsule are connected by a silane coupling agent.

[0008] When subjected to high-speed impact, the strain rate sensitive matrix hardens to absorb and disperse the impact energy; under normal wearing conditions, the phase change microcapsules absorb or release heat through phase change reactions to regulate the temperature of the head microenvironment.

[0009] Further, the strain rate sensitive matrix is ​​at least one of shear hardening gel (SSG), strain rate sensitive polymer, or polymer composite material. Preferably, the polymer is a composite material with ethylene-vinyl acetate copolymer (EVA), polylactic acid (PLA), or polyurethane (PU) as the matrix.

[0010] Furthermore, the core material of the phase change microcapsule is selected from at least one of n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-docosahexadecane, paraffin, fatty acid, hydrated salt, or polyethylene glycol.

[0011] Furthermore, the phase change microcapsules have a phase change temperature range of 20°C to 35°C. This temperature range is more suitable for the temperature environment of the human head, and also provides comfort, safety, chemical stability, and is non-toxic and harmless.

[0012] Furthermore, the strain rate sensitive-phase change composite material has one or more layers, and the mass ratio of phase change microcapsules in each layer can be different.

[0013] Furthermore, the mass fraction of phase change microcapsules in the strain rate sensitive-phase change composite material near the head is 30-40%, while the mass fraction of phase change microcapsules in the strain rate sensitive-phase change composite material farther from the head decreases sequentially.

[0014] Furthermore, the amino terminus of the silane coupling agent is bound to the phase change microcapsule, and the silane terminus of the silane coupling agent is bound to the strain rate sensitive matrix.

[0015] Preferably, the silane coupling agent is selected from silane coupling agent KH-550.

[0016] Furthermore, the lining also includes one or more fabric covering layers, which are disposed on the surface of the strain rate sensitive-phase change composite material or spaced apart between the strain rate sensitive-phase change composite material layers.

[0017] The fabric covering layer is a three-dimensional knitted spacer fabric, a non-woven fabric, or a high-performance textile fiber fabric to provide better structural support, breathability, and wearing comfort.

[0018] The second objective of this invention is to provide a method for preparing a strain rate-sensitive and thermal comfort phase change liner for bulletproof helmets, comprising the following steps: The core material, emulsifier, and silane coupling agent of the phase change microcapsule are dispersed in deionized water to form an emulsion; The emulsion, the prepolymer of the phase change microcapsule shell, and the uncured strain rate-sensitive matrix prepolymer are uniformly mixed to form a composite slurry. The composite slurry is at least one part, and after the composite slurry is layered, cross-linked, cured, and dried, the inner lining is obtained.

[0019] Furthermore, the preparation process of the emulsion is as follows: the silane coupling agent and the emulsifier are mixed in deionized water, heated in a water bath at 70~80°C, and molten core material is added under high-speed shearing to emulsify and form a stable emulsion.

[0020] Furthermore, boric acid crosslinking agent needs to be added during the preparation of the composite slurry.

[0021] Furthermore, the mass ratio of the uncured strain rate-sensitive matrix prepolymer to the boric acid crosslinking agent is 1~3:1.

[0022] Preferably, the mass ratio of the uncured strain rate-sensitive matrix prepolymer to the boric acid crosslinking agent is 2:1.

[0023] Furthermore, multiple composite slurries with different contents are injected into a mold in sequence, heated and cross-linked in an oven to cure, and dried to obtain the lining.

[0024] Furthermore, the mass ratio of the mixture of the core material, the shell prepolymer, and the emulsifier to the strain rate sensitive matrix prepolymer is 1~8:12~19.

[0025] Furthermore, the amount of the silane coupling agent added is 2-4% of the total mass of the core material, shell prepolymer, and emulsifier.

[0026] Furthermore, a method for preparing a strain rate-sensitive and thermal comfort phase change liner for a bulletproof helmet includes the following steps: S1. Preparation of capsule shell prepolymer: Melamine and formaldehyde are mixed and the pH value is adjusted to 8-9 with triethanolamine aqueous solution. The mixture is reacted in a water bath for 1-2 hours to obtain the capsule shell prepolymer. S2. Emulsion preparation: The silane coupling agent and emulsifier are mixed in deionized water, heated in a water bath at 70~80℃, and molten core material is added under high-speed shearing to emulsify and form a stable emulsion. S3. Preparation of composite slurry: After cooling the emulsion obtained in step S2 to 35~42℃, the pH value of the system is slowly adjusted to 3-5 with citric acid solution. Uncured strain rate sensitive matrix prepolymer and shell prepolymer are added in sequence and mixed evenly. Then, boric acid crosslinking agent is added and stirred for a while to obtain composite slurry. S4. At least one part of the composite slurry is injected into the mold in layers. After the cross-linking and curing reaction, it is placed in an oven and heated until dry to obtain the lining.

[0027] Furthermore, a method for preparing a strain rate sensitive and thermal comfort phase change liner for a bulletproof helmet includes the following steps: preparing a composite slurry I with a mass ratio of 3~4:6~7 of a mixture of core material, shell prepolymer, emulsifier and strain rate sensitive matrix prepolymer, and a composite slurry II with a mass ratio of 1~3:17~19 according to steps S1-S3; then injecting composite slurry I into a mold and spreading it evenly, followed by injecting composite slurry II and spreading it evenly; and then placing it in an oven and heating it until dry to obtain the liner.

[0028] Furthermore, before injecting the composite slurry into the mold, a layer of fabric covering is first laid flat inside the mold.

[0029] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. Intelligent Dual Function: This invention innovatively combines strain rate sensitive materials with phase change materials to achieve an intelligent response of "hardening protection during impact and temperature regulation for comfort during daily use," thus solving the long-standing contradiction between safety and comfort in the field of protective equipment.

[0030] 2. Significantly improved protective performance: When the lining is subjected to high-speed impact from a bullet or fragment, the material viscosity increases sharply or even hardens, which can more effectively absorb and disperse impact energy, providing the head with protection that surpasses traditional cushioning materials.

[0031] 3. Superior thermal comfort: The phase change microcapsules undergo a reversible solid-liquid phase change within the normal human body temperature range. When the head overheats, they absorb heat and melt to cool down; when the environment cools down, they release heat and solidify to keep warm, always maintaining the internal microenvironment of the helmet within a comfortable range, reducing thermal stress and enhancing sustained combat capability.

[0032] 4. Rational structure and easy application: By combining the composite system with the fabric covering layer, it can be easily integrated into existing helmet systems in the form of pads, while ensuring the mechanical strength and durability of the materials. The preparation method is simple and easy to achieve large-scale production.

[0033] 5. Interfacial synergistic enhancement effect: Through interfacial modification technology, phase change microcapsules and strain rate sensitive matrix achieve chemical bonding. The microcapsules are no longer just a filler phase, but become a reinforcing phase, jointly participating in and improving the dynamic mechanical response of the material. The energy absorption efficiency is increased by more than 15% compared with simple blended materials.

[0034] 6. Innovative preparation process: The one-step in-situ composite process simplifies the production process, reduces energy consumption and costs, and more importantly, solves the industry problem of high-performance phase change microcapsules being difficult to disperse uniformly in high-viscosity matrices and being easily damaged, thus ensuring the consistency and reliability of product performance.

[0035] 7. Environmental Adaptive Intelligent Response: This composite material can not only respond to mechanical shock and temperature changes, but also, in extremely humid environments, the hygroscopic shell material of the phase change microcapsule can help absorb sweat moisture and accelerate moisture evaporation through phase change heat absorption, thereby expanding the dual heat and moisture management function and improving wearing comfort in complex environments.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the strain rate sensitive and thermal comfort phase change liner for the bulletproof helmet of the present invention.

[0038] Figure 2 This is a schematic diagram of the structure of the strain rate sensitive and thermal comfort phase change liner for a bulletproof helmet with a fabric covering layer according to Embodiment 1 of the present invention.

[0039] Figure 3 This is a schematic diagram of the structure of the bulletproof helmet of the present invention.

[0040] In the attached figure, 1 is the strain rate sensitive matrix, 2 is the phase change microcapsule, 3 is the fabric covering layer, 4 is the shell, and 5 is the inner lining. Detailed Implementation

[0041] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0042] In addition, unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or prepared by existing methods.

[0043] Example 1 A strain rate sensitive and thermal comfort phase change liner for a bulletproof helmet includes a layer of strain rate sensitive-phase change composite material, the strain rate sensitive-phase change composite material comprising: Strain rate sensitive matrix; And a plurality of phase change microcapsules dispersed in the strain rate sensitive matrix, wherein the phase change microcapsules have a core-shell structure and the shell is melamine-formaldehyde resin; The strain rate-sensitive matrix and the phase change microcapsules are connected by a silane coupling agent.

[0044] This invention connects phase change microcapsules to a strain rate-sensitive matrix using a silane coupling agent. This not only solves the technical challenge of uniformly dispersing phase change microcapsules in high-viscosity strain rate-sensitive matrices, but also demonstrates excellent connectivity between the silane coupling agent and both the melamine-formaldehyde resin shell and the strain rate-sensitive matrix, improving interfacial compatibility and bonding strength. This combination of phase change microcapsules and a strain rate-sensitive matrix further enhances the dynamic mechanical response of the composite material and reduces the problem of localized stress concentration in a separate strain rate-sensitive matrix. Simultaneously, the melamine-formaldehyde resin can absorb sweat and other substances, keeping the scalp dry.

[0045] The strain rate sensitive matrix is ​​at least one of shear hardening gel (SSG), strain rate sensitive polymer, or polymer composite material. Preferably, the polymer composite material is a composite material with ethylene-vinyl acetate copolymer (EVA), polylactic acid (PLA), polyvinyl alcohol (PVA), or polyurethane (PU) as the matrix.

[0046] The core material of the phase change microcapsule is selected from at least one of n-heptadecane, n-octadecane, n-nonadecanane, n-eicosane, n-docosahexadecane, paraffin, fatty acid, hydrated salt or polyethylene glycol.

[0047] The phase change microcapsules have a phase change temperature range of 20°C to 35°C. This temperature range is more suitable for the temperature environment of the human head, and also provides comfort, safety, chemical stability, and is non-toxic and harmless.

[0048] The amino terminus of the silane coupling agent binds to the phase change microcapsule, while the silane terminus of the silane coupling agent binds to the strain rate sensitive matrix.

[0049] Preferably, the silane coupling agent is selected from silane coupling agent KH-550.

[0050] To provide better support, breathability, and wearing comfort, a fabric overlay is applied to the surface of the strain rate-sensitive phase change composite material. This overlay can be a three-dimensional knitted spacer fabric, a nonwoven fabric, or a high-performance textile fiber fabric.

[0051] Example 2 A strain rate sensitive and thermal comfort phase change liner for a bulletproof helmet includes at least one layer of strain rate sensitive-phase change composite material, wherein the strain rate sensitive-phase change composite material comprises: Strain rate sensitive matrix; And a plurality of phase change microcapsules dispersed in the strain rate sensitive matrix, wherein the phase change microcapsules have a core-shell structure and the shell is melamine-formaldehyde resin; The strain rate-sensitive matrix and the phase change microcapsules are connected by a silane coupling agent.

[0052] Unlike Example 1, the strain rate sensitive-phase change composite material has two layers, and each layer of strain rate sensitive-phase change composite material is covered with a fabric covering layer between the layers and on the surface of the strain rate sensitive-phase change composite material.

[0053] Example 3 A method for preparing a strain rate-sensitive and thermal comfort phase change liner for a bulletproof helmet includes the following steps: S1. Preparation of capsule prepolymer: Melamine and formaldehyde are mixed at a molar ratio of 1:2, and the pH value is adjusted to 8-9 with triethanolamine aqueous solution. The mixture is reacted in a water bath at 75°C for 1 hour until the solution becomes clear and transparent to obtain melamine-formaldehyde capsule prepolymer. After cooling to room temperature, it is ready for use. S2. Emulsion preparation: Mix silane coupling agent KH-550 and emulsifier in deionized water, heat in a 70°C water bath, and add molten n-octadecane core material under high-speed shear at 10000 rpm. Emulsify for 30 min to form a stable emulsion. The mass of silane coupling agent added is 2% of the emulsion mass. S3. Preparation of Composite Slurry: After cooling the emulsion obtained in step S2 to 35~42℃, the pH value of the system is slowly adjusted to 4 with citric acid solution. Uncured hydroxyl silicone oil and shell prepolymer are added sequentially and mixed evenly. Then, boric acid crosslinking agent is added, and the mixture is stirred continuously to obtain the composite slurry. The molar ratio of hydroxyl silicone oil to boric acid is 2:1; the mass ratio of the total mass of emulsifier, n-octadecane, and melamine-formaldehyde shell prepolymer to hydroxyl silicone oil is 3:7.

[0054] S4. One portion of composite slurry is injected into the mold in layers. After the cross-linking and curing reaction, it is placed in an oven and heated until dry to obtain the lining.

[0055] Example 4 Unlike Example 3, the strain rate sensitive-phase change composite material has two layers, and the preparation method includes the following steps: S1. Preparation of capsule prepolymer: Melamine and formaldehyde are mixed at a molar ratio of 1:2, and the pH value is adjusted to 8-9 with triethanolamine aqueous solution. The mixture is reacted in a water bath at 75°C for 1 hour until the solution becomes clear and transparent to obtain melamine-formaldehyde capsule prepolymer. After cooling to room temperature, it is ready for use. S2. Emulsion preparation: Mix silane coupling agent KH-550 and emulsifier in deionized water, heat in a 70°C water bath, and add molten n-octadecane core material under high-speed shear at 10000 rpm. Emulsify for 30 min to form a stable emulsion. The mass of silane coupling agent added is 2% of the emulsion mass. S3. Preparation of composite slurry: After cooling the emulsion obtained in step S2 to 35~42℃, the pH value of the system is slowly adjusted to 4 with citric acid solution. Uncured hydroxyl silicone oil and shell prepolymer are added and mixed evenly. Then, boric acid crosslinking agent is added, and the mixture is stirred continuously to obtain the composite slurry. The molar ratio of hydroxyl silicone oil to boric acid is 2:1.

[0056] S4. Repeat steps S1-S3 to prepare two composite slurries. The mass ratio of the emulsifier, n-octadecane, and melamine-formaldehyde shell prepolymer to hydroxyl silicone oil in composite slurry I is 3:7. The mass ratio of the emulsifier, n-octadecane, and melamine-formaldehyde shell prepolymer to hydroxyl silicone oil in composite slurry II is 1:9.

[0057] First, composite slurry I is poured into the mold and spread evenly, then composite slurry II is poured in and spread evenly. Then, it is placed in an oven and heated until dry to obtain the lining.

[0058] Example 5 Unlike Example 4, after preparing composite slurry I and composite slurry II in step S4, a layer of high-performance textile fiber fabric is first laid flat in the mold. Then, composite slurry I is injected into the mold and laid flat, followed by composite slurry II, and then another layer of high-performance textile fiber fabric is laid flat on top. Finally, it is placed in an oven and heated until dry to obtain the lining.

[0059] In a preferred embodiment, the shape of the fabric covering layer is consistent with the shape of the lining.

[0060] For low-velocity impacts, the energy absorption performance was tested according to the drop hammer impact test in the GA293-2023 standard. The same impact energy was used to test the traditional polyurethane foam helmet, the helmets with liners from Examples 3 and 4, and all three helmets used were from the same commercially available batch. The tests showed that the force transmitted to the test head mold by the liner of Example 3 during impact was 3594N, an improvement of over 30% in energy absorption capacity compared to the traditional polyurethane foam liner. The force transmitted to the test head mold by the liner of Example 4 during impact was 2947N, an improvement of 18% in energy absorption capacity compared to Example 3.

[0061] For high-speed impact testing, according to the GJB5115A-2012 standard, the V50 test results for lined bulletproof helmets showed that, with essentially the same V50 data, the back protrusion of the bulletproof helmet with the polyurethane foam liner was 24mm, while that of the bulletproof helmet with the liner of Example 3 was 21mm. The back protrusion of the bulletproof helmet with the liner of Example 4 was 18mm, effectively reducing blunt force trauma injuries to soldiers caused by high-speed impacts. It is evident that the gradient design achieved a directional response of the composite material at different strain rates, significantly improving its impact resistance.

[0062] A metal head mold identical in size and shape to a real human head was used, with an integrated temperature sensor and humidity meter, and its surface could simulate sweating. The lining of Example 4 was placed in a closed environment at 35°C for 10 hours, and the temperature change of the lining surface was monitored. The traditional polyurethane lining, the lining of Example 3 of this invention, and the lining of Example 4 were respectively placed in a closed environment at 35°C and 90%RH for 10 hours, and the sweat evaporation rate and specific heat capacity of the lining surface were monitored. The results are shown in Table 1.

[0063] The helmet model equipped with the liner of this invention can maintain a stable internal temperature of 35°C for approximately 2.5 hours longer, significantly improving thermal comfort.

[0064] Comfort tests revealed that both the fabric-reinforced lining of Example 3 and the gradient lining of Example 4 exhibited excellent breathability. Particularly in high-temperature and high-humidity environments (35°C, 90%RH), the gradient lining of Example 4, due to its directional moisture-wicking and heat-retaining capabilities, showed a nearly 30% increase in sweat evaporation rate and a more than 40% increase in specific heat capacity compared to traditional polyurethane materials. This demonstrates that the lining material of the present invention possesses stronger heat absorption and storage capabilities, along with better breathability. It can effectively conduct heat and moisture in high-temperature and high-humidity environments, and effectively regulate the thermal balance of the head's microenvironment during temperature changes, thereby improving wearing comfort.

[0065] Table 1 Sample Sweat Evaporation Rate (g / m 2 ·h) Specific heat capacity (J / kg K) Conventional polyurethane inner liner 200 1412 Example 3 inner liner 260 1987 Example 4 inner liner 258 1992 To enhance the breathability of the liner and improve wearing comfort, the mold used in this invention during curing is identical in shape to the inside of the bulletproof helmet shell, and multiple holes are formed in the middle, making the molded liner porous and increasing the breathability of the helmet liner.

[0066] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0067] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet, characterized by, The strain rate sensitive-phase change composite material comprises at least one strain rate sensitive-phase change composite material, the strain rate sensitive-phase change composite material comprises: a strain rate sensitive matrix; and a plurality of phase change microcapsules dispersed in the strain rate sensitive matrix, the phase change microcapsules are in a core-shell structure, and the capsule shell is melamine formaldehyde resin; the strain rate sensitive matrix and the phase change microcapsules are connected through a silane coupling agent.

2. A strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet according to claim 1, characterized in that: The strain rate sensitive matrix is at least one of a shear thickening gel, a strain rate sensitive polymer or a high molecular polymer composite material.

3. A strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet according to claim 1, characterized in that: The capsule core material of the phase change microcapsules is selected from at least one of n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane paraffin, a fatty acid, a hydrated salt or polyethylene glycol.

4. A strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet according to claim 1, characterized in that: The mass fraction of the phase change microcapsules in the strain rate sensitive-phase change composite material close to the head is 30-40%, and the mass fraction of the phase change microcapsules in the strain rate sensitive-phase change composite material away from the head decreases in turn.

5. The process for the preparation of a strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet according to any one of claims 1-4, characterized in that, The method comprises the following steps: The capsule core material of the phase change microcapsules, an emulsifier and a silane coupling agent are dispersed in deionized water to form an emulsion; The emulsion, a capsule shell prepolymer of the phase change microcapsules and an uncured strain rate sensitive matrix prepolymer are uniformly mixed to form a composite slurry; The composite slurry is at least one, and at least one of the composite slurries is layered, cross-linked and cured to obtain the inner lining.

6. A method of making a strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet as in claim 5, wherein: A boric acid cross-linking agent is further added in the preparation of the composite slurry.

7. A method of making a strain rate sensitive and cold-heat comfort phase change inner liner for a ballistic helmet as in claim 5, wherein: The mass ratio of the mixture of the capsule core material, the capsule shell prepolymer and the emulsifier to the strain rate sensitive matrix prepolymer is 1-8:12-19.

8. The method of claim 5, wherein the phase change material is a mixture of 50% by weight of the phase change material of a paraffin wax and 50% by weight of the phase change material of a fatty acid ester. The addition amount of the silane coupling agent is 2-4% of the total mass of the capsule core material, the capsule shell prepolymer and the emulsifier.

9. The method of claim 5, wherein the phase change material is a mixture of 70% by weight of a paraffin wax and 30% by weight of a fatty acid ester. The method comprises the following steps: S1, preparation of the capsule shell prepolymer: melamine is mixed with formaldehyde, and then the pH value is adjusted to 8-9 by using a triethanolamine aqueous solution, and the mixture is reacted in a water bath for 1-2 h to obtain the capsule shell prepolymer; S2, preparation of the emulsion: a silane coupling agent and an emulsifier are mixed in deionized water, heated in a water bath at 70-80°C, and then a molten capsule core material is added under high-speed shearing to form a stable emulsion; S3, preparation of the composite slurry: the emulsion obtained in step S2 is cooled to 35-42°C, and then the pH value of the system is slowly adjusted to 3-5 by using a citric acid solution, an uncured strain rate sensitive matrix prepolymer and a capsule shell prepolymer are mixed uniformly, and then a boric acid cross-linking agent is added, and the mixture is continuously stirred to obtain the composite slurry; S4, the composite slurry is at least one, and at least one of the composite slurries is layered and injected into a mold, and then cross-linked and cured, and placed in an oven for drying to obtain the inner lining.

10. The method of claim 9, wherein the phase change material is a mixture of 50% by weight of the phase change material of a paraffin wax and 50% by weight of the phase change material of a fatty acid ester. The method comprises the following steps: According to steps S1-S3, one portion of a composite slurry I and one portion of a composite slurry II are prepared, the mass ratio of the mixture of the capsule core material, the capsule shell prepolymer and the emulsifier to the strain rate sensitive matrix prepolymer in the composite slurry I is 3-4:6-7, and the mass ratio of the mixture of the capsule core material, the capsule shell prepolymer and the emulsifier to the strain rate sensitive matrix prepolymer in the composite slurry II is 1-3:17-19, the composite slurry I is first injected into the mold and then the composite slurry II is injected into the mold, the mold is then placed in an oven for drying to obtain the inner lining.

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