Strain sensing wrap yarn for underwater and fire rescue scenes and preparation method thereof

Abstract

The invention provides a strain sensing wrap yarn for underwater and fire rescue scenes and a preparation method of the strain sensing wrap yarn, and belongs to the technical field of wrapping composite spinning. The strain sensing wrap yarn for underwater and fire rescue scenes sequentially comprises an elastic core yarn, a cross wrapping type silver-plated filament layer, an elastic hose nesting layer and a basalt fiber wrapping layer from inside to outside, the strain sensing wrap yarn with excellent mechanical flexibility and elasticity, structural stability and strong flame-retardant and heat-insulating properties can be prepared through cooperation of a hollow ingot wrapping spinning device and a nesting process, solvent use, coating, dipping or multi-step assembly links involved in a chemical preparation process are avoided, the production process is simplified, the production cost is reduced, and the production efficiency is improved. The wrap yarn is simple in structure, low in cost and environment-friendly, reduces chemical consumption, energy consumption and the like, can realize stable and reliable strain monitoring in air, underwater environment, short-time burning and other multi-scene complex working conditions, and is particularly suitable for underwater, fire rescue and other extreme environments.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wrapping composite spinning, and particularly relates to a strain sensing wrapping yarn for underwater and fire rescue scenarios and a preparation method thereof. BACKGROUND

[0002] With the increasing demand for intelligent wearable devices in the field of emergency rescue, the traditional rigid electronic sensor has insufficient anti-sensing interference ability in complex extreme working conditions (such as underwater wetness, high temperature fire, etc.), which has become a key bottleneck restricting its further promotion and application. Developing a high-reliability strain sensor that can adapt to underwater and high-temperature fire environments at the same time not only has important strategic significance, but also is an urgent need to improve the safety level of rescue personnel. Such a sensor needs to have the ability to monitor movement in underwater rescue, as well as structural stability and signal fidelity transmission in fire environments, to realize real-time and reliable sensing and early warning of the state of rescue personnel.

[0003] In recent years, although flexible electronic technology has made significant progress, existing strain sensing materials still have certain limitations in dealing with complex multi-factor coupled environments. At present, underwater sensing yarns mostly use electrospun polyurethane nanofiber membranes or PDMS and other elastomers for impregnation (or coating) encapsulation, but these methods have certain inherent technical bottlenecks: the mechanical strength and durability of electrospun nanofiber membranes are insufficient, and they are prone to membrane rupture or damage under repeated wear or underwater mechanical impact, leading to failure of the waterproof barrier and degradation of sensing performance; the PDMS and other elastomer impregnation method has problems such as difficulty in accurately controlling coating thickness and uniformity, inherent decrease in material flexibility, weak interfacial bonding, and mechanical mismatch with biological bodies, which can easily cause interfacial peeling or micro-crack propagation under dynamic strain, ultimately leading to sensing signal drift or complete failure. In addition, most existing sensing structures are designed for a single environmental factor and lack the ability to simultaneously resist underwater environments and high-temperature fire attacks, making it difficult to meet the stringent requirements for integrated performance of strain sensing materials in rescue operations.

[0004] Hollow spindle wrapping spinning technology has unique advantages in realizing yarn structure redesign and multifunctional reconstruction, and can achieve precise wrapping and stable interfacial bonding between multiple heterogeneous materials, providing an effective technical path for developing multifunctional strain sensing yarns. This technology is mature, highly adaptable, and easy to mass-produce. Therefore, based on hollow spindle wrapping spinning technology, it is a technical difficulty problem to be solved by the present application to construct a strain sensing wrapping yarn that has excellent mechanical flexibility, structural stability, and strong flame-retardant and heat-insulating properties. SUMMARY

[0005] To solve the above technical problems, the present application proposes a strain sensing wrapping yarn for underwater and fire rescue scenarios and a preparation method thereof.

[0006] To achieve the above object, the present application provides the following technical solutions.

[0007] One of the technical solutions of the present application is:

[0008] A strain sensing cover yarn for underwater and fire rescue scenarios, from inside to outside, in order, is an elastic core yarn, a cross-wrapped silver-plated filament layer, an elastic hose nesting layer, and a basalt fiber cover layer.

[0009] Further, the fineness of the elastic core yarn is 420D-1680D.

[0010] Further, the fineness of the silver-plated filament in the cross-wrapped silver-plated filament layer is 20D-400D, preferably 70D-350D.

[0011] Further, the material of the elastic hose is any one of silicone rubber, styrene-butadiene rubber, and fluorine rubber; the inner diameter of the elastic hose is 0.3mm-2.0mm, and the outer diameter is 0.8mm-6.0mm, preferably, the inner diameter is 0.6mm-1.6mm, and the outer diameter is 1.2mm-3.2mm.

[0012] Further, the fineness of the basalt fiber in the basalt fiber cover layer is 0.15mm-0.35mm.

[0013] The second technical solution of the present application is:

[0014] A preparation method of a strain sensing cover yarn for underwater and fire rescue scenarios, comprising the following steps:

[0015] (1) The elastic core yarn is used as the core layer, is fed into the hollow spindle wrap spinning machine through the positive feeding roller, is introduced into the lower layer hollow spindle center tube of the hollow spindle wrap spinning machine after winding the guide hook, and is led out from the upper end of the lower layer hollow spindle center tube; the silver-plated filaments nested on the lower layer and the upper layer hollow spindle are cross-wrapped on the surface of the elastic core yarn in turn, and then the bidirectional pre-cover yarn of the cross-wrapped silver-plated filaments on the elastic core yarn is wound on the bobbin through the yarn guide roller and the traverse guide hook, to obtain the bidirectional pre-cover yarn;

[0016] (2) The elastic hose is nested on the surface of the bidirectional pre-cover yarn to form the bidirectional pre-cover yarn with the elastic hose nesting structure;

[0017] (3) The bidirectional pre-cover yarn with the elastic hose nesting structure is used as the core layer and is fed into the upper layer hollow spindle center tube of the hollow spindle wrap spinning machine again, and the basalt fiber nested on the upper layer hollow spindle is wrapped on the surface of the bidirectional pre-cover yarn with the elastic hose nesting structure to obtain the strain sensing cover yarn for underwater and fire rescue scenarios.

[0018] Further, in step (1), the pre-drafting multiple of the elastic core yarn is 1.5-4.5, preferably 2.5-4.5.

[0019] Further, in step (1), the winding directions of the silver-plated filaments on the lower layer and the upper layer hollow spindles are opposite, forming a cross spiral structure, and the covering twist is 300-1800 twists per meter (T / m), preferably the covering twist of the upper layer silver-plated filaments is 1200-1800 T / m, and the covering twist of the lower layer silver-plated filaments is 800-1800 T / m.

[0020] Further, in step (3), the basalt fiber wrapping twist is any one of Z twist or S twist; and the basalt fiber covering twist is 1000-3000 twists per meter, preferably 1750-3000 T / m.

[0021] The third technical scheme of the present application is as follows:

[0022] An application of the above strain sensing covered yarn for underwater and fire rescue scenarios in underwater rescue and fire rescue.

[0023] Compared with the prior art, the present application has the following advantages and technical effects:

[0024] (1) The preparation method of the present application is simple and practical, and a strain sensing covered yarn with excellent mechanical flexibility, structural stability and strong flame-retardant and heat-insulating properties can be prepared by the physical processing method of the combination of the hollow spindle wrapping spinning device and the nesting process. This method avoids the use of solvents, coating, dipping or multi-step assembly involved in the chemical preparation process, which not only simplifies the production process, but also reduces chemical consumption and energy consumption, etc., and is green and environmentally friendly.

[0025] (2) The introduction of the elastic hose nesting layer in the present application realizes the complete packaging of the sensing core, effectively isolates water vapor and liquid penetration, and ensures the long-term stable operation of the strain sensing covered yarn in underwater environment.

[0026] (3) The outermost basalt fiber in the present application endows the covered yarn with excellent flame-retardant and heat-insulating protective functions. Experimental data show that after local burning by a lighter for 5 seconds, the basalt fiber structure is complete, and the inner elastic hose is not damaged; after the burning time is extended to 10 seconds, the basalt fiber still maintains the structural integrity, and only the inner elastic hose appears slight ablation. This proves that it can effectively resist the invasion of high-temperature open flame for a short time.

[0027] (4) The covered yarn benefits from the synergistic effect of the elastic core yarn and the elastic hose nested layer, and exhibits excellent fatigue resistance and structural durability. The results show that the covered yarn still maintains stable mechanical stability (excellent fatigue resistance) after 100 cycles under large tensile strain (such as 100%, 150%, etc.), ensuring that it has a long-term reliable service life when subjected to repeated tensile deformation in rescue work.

[0028] (5) The spinning equipment and technology used in the present application are mature, have the advantages of coherent spinning process flow, low processing energy consumption, convenient and practical production, and can be mass-produced. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0030] Figure 1 The present application is a preparation process and application of a strain sensing covered yarn for underwater and fire rescue scenarios;

[0031] Figure 2 The present application is a preparation process and application of a strain sensing covered yarn for underwater and fire rescue scenarios;

[0032] Figure 3 The present application is a preparation process and application of a strain sensing covered yarn for underwater and fire rescue scenarios;

[0033] Figure 4 The present application is a preparation process and application of a strain sensing covered yarn for underwater and fire rescue scenarios;

[0034] Figure 5Stress-strain curves of the strain sensing wrap yarn prepared in Example 1 of the present application under (a) 100% tensile strain and (c) 150% tensile strain, respectively, after 100 cycles of tensile test; (b) and (d) are the trend curves of the tensile mechanical peak value under the corresponding strain conditions, respectively, with the number of cycles, and the inset is a local magnified view of the mechanical peak value in a specific time period;

[0035] Figure 6 Comparison of the state of the strain sensing wrap yarn prepared in Example 1 of the present application before (a) and after (b) finger bending in underwater environment;

[0036] Figure 7 Spatter of sparks of the yarn body of the strain sensing wrap yarn prepared in Example 1 of the present application under open flame burning (a); (b) is the color change of the local surface of the wrap yarn after burning for 10 seconds; the damage morphology of the inner layer elastic hose after peeling off the outermost basalt fiber after (c) 5 seconds and (d) 10 seconds of burning;

[0037] Figure 8 Resistance change of the strain sensing wrap yarn prepared in Example 1 of the present application before and after finger bending under different working conditions: (a) in air; (b) underwater; (c) after 10 seconds of open flame burning;

[0038] Figure 9 Burning situation of the strain sensing wrap yarn of Comparative Example 1 with only nested elastic hose after being directly burned by a lighter for a few seconds, wherein (a) is 0s, (b) is 2s, (c) is 4s, and (d) is 6s;

[0039] Figure 10 Resistance change rate of the silver-plated filament component used to prepare the strain sensing wrap yarn of Comparative Example 2 after being placed in air for 30 seconds and then immersed in water;

[0040] Figure 11 Appearance morphology of the strain sensing wrap yarn prepared in Example 2 of the present application (a) and after direct burning for 10 seconds (b);

[0041] Figure 12 Appearance morphology of the strain sensing wrap yarn prepared in Example 3 of the present application (a) and after direct burning for 10 seconds (b);

[0042] Figure 13 Appearance morphology of the strain sensing wrap yarn prepared in Example 4 of the present application (a) and after direct burning for 10 seconds (b). DETAILED DESCRIPTION

[0043] The various illustrative embodiments of the present application will now be described in detail in connection with the accompanying drawings. This description is not to be considered limiting of the application, but rather a description of certain modes contemplated by the inventor.

[0044] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of, for example, the upper limit and the lower limit of the range are also specifically disclosed. Each intermediate value of the stated range and each smaller range that falls within the stated range are also included in the present application. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.

[0045] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe in detail the methods and / or materials that are related to the present application. In case of conflict, the content of the present specification will control.

[0046] Many modifications and variations of the present application described in the specification are possible without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application. The specification and examples are illustrative only.

[0047] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional elements or steps.

[0048] The strain sensing wrap yarn for underwater and fire rescue scene of the embodiment of the present application comprises, from inside to outside, an elastic core yarn, a cross-wrapped silver-plated filament layer, an elastic hose nesting layer, and a basalt fiber coating layer.

[0049] In the preferred embodiment of the present application, the fineness of the elastic core yarn is 420D-1680D.

[0050] In the preferred embodiment of the present application, the fineness of the silver-plated filament in the cross-wrapped silver-plated filament layer is 20D-400D, preferably 70D-350D.

[0051] In the preferred embodiment of the present application, the material of the elastic hose is any one of silicone rubber, styrene-butadiene rubber, and fluorine rubber; the inner diameter of the elastic hose is 0.3mm-2.0mm, and the outer diameter is 0.8mm-6.0mm, preferably, the inner diameter is 0.6mm-1.6mm, and the outer diameter is 1.2mm-3.2mm.

[0052] In the preferred embodiment of the present application, the fineness of the basalt fibers in the basalt fiber coating layer is 0.15mm-0.35mm.

[0053] The present application builds an integrated system of mechanical support-sensing core-sealing protection-flame-retardant barrier through the functional complementation and structural synergy of four layers of heterogeneous materials, and each layer is designed to serve the strain sensing reliability in extreme environments. The specific principles are as follows:

[0054] 1. The elastic core yarn (inner layer) serves as the mechanical framework of the covered yarn, and its core function is to provide the necessary elastic support and tensile deformation capability, which is the primary prerequisite for realizing large-strain cyclic monitoring. The elastic core yarn (such as spandex) itself has high elastic recovery characteristics, which is the core guarantee for achieving "100 cycles of mechanical stability". It can withstand repeated stretching without significant deformation accumulation; the fineness range of 420D-1680D can balance the elastic recovery force and structural lightweighting, and too fine (<420D) will result in insufficient mechanical strength and easy breakage during stretching; too thick (>1680D) will reduce the overall flexibility and affect the wearing adaptability in rescue scenarios.

[0055] 2. The cross-wrapped silver-plated filament layer (second layer) serves as the conductive sensing unit, which realizes strain monitoring through the resistance change caused by deformation, and is the "perception core" of the covered yarn. The silver-plated filament has excellent electrical conductivity, and its surface silver layer forms a continuous conductive path; when the covered yarn is stretched or contracted, the geometric shape (such as length, contact area, etc.) of the silver layer path changes and is converted into a monitorable resistance signal, thereby realizing the measurement of the strain state; the lower and upper silver-plated filaments have "opposite winding directions (such as Z twist / S twist), forming a cross-spiral structure", which can avoid the problem of "stretching leading to filament breakage and conductive path interruption" when wrapped in a single direction; the cross-spiral can evenly distribute the tensile force to multiple filaments, avoiding stress concentration and ensuring the continuity of the conductive path during deformation, improving the stability and consistency of the sensing signal, as well as the durability under repeated stretching; the fineness of 20D-400D can match the tensile properties of the elastic core yarn, and too fine (<20D) is prone to breakage when cross-wrapped, and too thick (>400D) will reduce the adhesion to the elastic core yarn, resulting in uneven resistance changes during deformation.

[0056] 3. The elastic hose nesting layer (third layer) serves as a waterproof sealing barrier and a secondary elastic buffer layer, solving the problem of water vapor penetration in underwater environments and improving overall fatigue resistance. The elastic hose (silicone rubber, styrene-butadiene rubber, etc.) completely wraps the cross-wrapped silver-plated filaments in the inner layer through the "nesting process" to form a physical sealed cavity, which can effectively isolate water vapor and liquid, prevent the silver-plated layer from oxidizing or short-circuiting, and ensure the reliability of underwater strain sensing. At the same time, the hose itself has elasticity and forms a double-elastic layer with the inner elastic core filaments to collaboratively buffer and disperse stress during stretching, reducing the local stress concentration of silver-plated filaments, which is one of the key factors for "100% / 150% strain cycle for 100 times still maintaining mechanical stability". In terms of size design, its inner diameter needs to be accurately matched with the diameter of the bidirectional pre-coated yarn in the inner layer (too loose may fall off, too tight may limit deformation); its outer diameter needs to balance "sealing thickness" and "overall light weight" to ensure that the subsequent basalt fiber layer can be tightly wrapped.

[0057] 4. The basalt fiber wrapping layer (outer layer) serves as an extreme high-temperature protection layer to resist short-term open flame burning in fire scenarios and protect the inner sensing core and sealing structure from damage. Basalt fiber itself has the characteristics of high temperature resistance (melting point about 1500℃) and non-combustibility, and the physical barrier formed by its tight wrapping can block the direct contact between open flame and the inner layer material, delaying heat transfer; a fineness of 0.15mm-0.35mm can ensure the balance between tightness and air permeability during wrapping, too fine (<0.15mm) may cause uneven wrapping, and too thick (>0.35mm) may result in too large interlayer space, reducing the heat insulation effect; in combination with "1000-3000 twists per meter", the wrapping firmness of the fiber layer can be further improved to prevent it from falling off during burning and maintain the integrity of protection.

[0058] The present application also provides a preparation method of strain sensing wrapped yarn for underwater and fire rescue scenarios, comprising the following steps:

[0059] (1) The elastic core filament is used as the core layer, which is fed into the hollow spindle wrapping spinning machine through the positive feeding roller, and then introduced into the lower hollow spindle center tube of the hollow spindle wrapping spinning machine after winding around the guide hook, and then drawn out from the upper end of the lower hollow spindle center tube; the silver-plated filaments nested on the lower and upper hollow spindles are cross-wrapped on the surface of the elastic core filament in turn, and then the cross-wrapped silver-plated filaments are wound onto the yarn drum through the yarn guide roller and the traverse guide hook to obtain the bidirectional pre-coated yarn;

[0060] (2) The elastic hose is nested on the surface of the bidirectional pre-coated yarn to form a bidirectional pre-coated yarn with an elastic hose nesting structure;

[0061] (3) The bidirectional pre-coated yarn of the elastic hose nesting structure is taken as the core layer, and is fed into the upper layer hollow spindle center tube of the hollow spindle package spinning machine again, and the basalt fiber nested on the upper layer hollow spindle is coated on the surface of the bidirectional pre-coated yarn of the elastic hose nesting structure, so that the strain sensing coated yarn for the underwater and fire rescue scene is obtained.

[0062] In step (1) of the preferred embodiment of the present application, the pre-drafting multiple of the elastic core yarn is 1.5-4.5, preferably 2.5-4.5.

[0063] In step (1) of the preferred embodiment of the present application, the winding directions of the silver-plated filaments on the lower layer and the upper layer hollow spindles are opposite, and the cross spiral structure is formed, and the coating twist is 300-1800 twists per meter (T / m), preferably the coating twist of the upper layer silver-plated filament is 1200-1800 T / m, and the coating twist of the lower layer silver-plated filament is 800-1800 T / m.

[0064] In step (2) of the preferred embodiment of the present application, the bidirectional pre-coated yarn of the elastic hose and the silver-plated filament of step (1) are cut respectively, and the lengths of the two should be kept consistent, and the specific value is determined according to the required length of the finished strain sensing coated yarn 16, and in order to ensure continuous production, the required length is preferably 100 meters or more.

[0065] In step (3) of the preferred embodiment of the present application, the wrapping twist of the basalt fiber is any one of Z twist or S twist; the coating twist of the basalt fiber is 1000-3000 twists per meter, preferably 1750-3000 T / m.

[0066] The embodiment of the present application also proposes an application of the above-mentioned strain sensing coated yarn for the underwater and fire rescue scene in underwater rescue and fire rescue.

[0067] The preparation process and application of the strain sensing coated yarn for the underwater and fire rescue scene of the present application are shown in Figure 1 .

[0068] The technical solutions of the present application are further described below through examples.

[0069] Example 1

[0070] A preparation process of a strain sensing coated yarn for the underwater and fire rescue scene, and a principle schematic diagram is shown in Figure 2Wherein, 1 - elastic core filament; 2 - positive feed roller; 3 - guide hook; 4 - lower layer hollow spindle center tube; 5 - lower layer hollow spindle; 6 - upper layer hollow spindle; 7 - lower layer silver-plated filament; 8 - upper layer silver-plated filament; 9 - yarn guide roller; 10 - traversing guide hook; 11 - bidirectional pre-coated yarn of silver-plated filament cross-wrapped elastic core filament; 12 - yarn drum; 13 - elastic hose; 14 - bidirectional pre-coated yarn of elastic hose nesting structure; 15 - basalt fiber; 16 - strain sensing coated yarn. The preparation method specifically comprises the following steps (I), (II) and (III):

[0071] (I) Take the spandex elastic core filament 1 as the core layer, feed it into the hollow spindle wrapping spinning machine through the positive feed roller 2 and apply a certain multiple of pre-draft, then after winding around the guide hook 3, introduce it into the lower layer hollow spindle center tube 4 of the hollow spindle wrapping spinning machine, and lead it out from the upper end of the lower layer hollow spindle center tube 4; wrap the silver-plated filaments 7 and 8 nested on the lower layer hollow spindle 5 and the upper layer hollow spindle 6 on the surface of the elastic core filament 1 in a cross-wrapped structure, and then through the yarn guide roller 9 and the traversing guide hook 10, wind the bidirectional pre-coated yarn 11 of silver-plated filament cross-wrapped elastic core filament onto the yarn drum 12 to obtain the bidirectional pre-coated yarn;

[0072] (II) Nest the elastic hose 13 on the surface of the bidirectional pre-coated yarn obtained in step (I) to form a bidirectional pre-coated yarn of elastic hose nesting structure, specifically: cut the elastic hose 13 and the bidirectional pre-coated yarn 11 of silver-plated filament cross-wrapped elastic core filament obtained in step (I) respectively, and the lengths of the two should be consistent, the specific value is determined according to the length of the finished product of the strain sensing coated yarn 16 required finally, in order to ensure the continuous production of step (III), preferably, the required length is 100 meters. Take a long enough copper wire and tie it to one end of the bidirectional pre-coated yarn 11 of silver-plated filament cross-wrapped elastic core filament obtained in step (I), use the copper wire to guide the bidirectional pre-coated yarn 11 of silver-plated filament cross-wrapped elastic core filament obtained in step (I) to pass through the elastic hose 13, and finally untie the copper wire, that is, the assembly is completed, and the bidirectional pre-coated yarn 14 of elastic hose nesting structure is obtained;

[0073] (III) Take the bidirectional pre-coated yarn 14 of elastic hose nesting structure as the core layer, feed it into the center tube of the upper layer hollow spindle 6 of the hollow spindle wrapping spinning machine again, wrap the basalt fiber 15 nested on the upper layer hollow spindle 6 on the surface of the bidirectional pre-coated yarn 14 of elastic hose nesting structure to obtain the strain sensing coated yarn 16 of multi-level structure facing underwater and fire rescue scene.

[0074] The key process parameters of the strain sensing coated yarn facing underwater and fire rescue scene of spinning example 1 are shown in Table 1.

[0075] Example 2

[0076] The preparation method is the same as that of Example 1, except that the key process parameters are different, as shown in Table 1.

[0077] Example 3

[0078] The preparation method is the same as that of Example 1, except that the key process parameters are different, as shown in Table 1.

[0079] Example 4

[0080] The preparation method is the same as that of Example 1, except that the key process parameters are different, as shown in Table 1.

[0081] Table 1 Spinning key process parameters used in each embodiment of the present application

[0082] Spinning key process parameters Example 1 Example 2 Example 3 Example 4 Spindle speed 6500 r / min 8750 r / min 7000 r / min 5000 r / min Elastomeric core filament Lycra 840 D Lycra 1680 D Lycra 1120 D Lycra 420 D Elastomeric core filament pre-drafting multiplier 3.0 4.5 3.5 2.5 Silver plated filament gauge 140 D 200 D 350 D 70 D Lower silver plated filament capping twist direction Z twist Z twist S twist S twist Upper silver plated filament capping twist direction S twist S twist Z twist Z twist Lower silver plated filament capping twist T / m 1200 1000 800 1800 Upper silver plated filament capping twist T / m 1200 1500 1200 1800 Elastomeric hose material Silicone rubber Styrene butadiene rubber Silicone rubber Fluoro rubber Elastomeric hose inner / outer diameter mm 1.0 / 2.0 1.6 / 3.2 1.3 / 2.3 0.6 / 1.2 Basalt fibre fineness mm 0.25 0.25 0.35 0.15 Basalt fibre capping twist direction S twist Z twist Z twist S twist Basalt fibre capping twist T / m 2600 2800 1750 3000 Strain sensing performance of capping yarn Excellent Excellent Excellent Excellent

[0083] Comparative Example 1

[0084] The same as Example 1, except that step (III) is omitted, specifically:

[0085] (I) Take the spandex elastic core yarn as the core layer, actively feed it into the hollow spindle wrapping spinning machine through the roller, and apply a certain multiple of pre-draft. After winding around the guide hook, it is introduced into the lower hollow spindle center tube of the hollow spindle wrapping spinning machine, and is drawn out from the upper end of the lower hollow spindle center tube. The silver-plated filaments nested on the lower and upper hollow spindles are cross-wrapped on the surface of the elastic core yarn in a tight state to form a cross-wrapped structure. Then, through the guide roller and the traverse guide hook, the bidirectional pre-wrapped yarn of the silver-plated filaments cross-wrapped elastic core yarn is wound onto the bobbin to obtain the bidirectional pre-wrapped yarn.

[0086] (II) Nest the elastic hose on the surface of the bidirectional pre-wrapped yarn obtained in step (I) to form a bidirectional pre-wrapped yarn with an elastic hose nesting structure. Specifically, the elastic hose 13 and the bidirectional pre-wrapped yarn 11 of the silver-plated filaments cross-wrapped elastic core yarn obtained in step (I) are cut respectively, and their lengths should be consistent. The specific value is determined according to the final required length of the strain sensing wrapped yarn 16 product. Preferably, in order to ensure continuous production in step III, the required length is 100 meters. A copper wire long enough is tied to one end of the bidirectional pre-wrapped yarn of the silver-plated filaments cross-wrapped elastic core yarn obtained in step (I), and the copper wire is used to guide the bidirectional pre-wrapped yarn of the silver-plated filaments cross-wrapped elastic core yarn through the elastic hose. Finally, the copper wire is untied, and the assembly is completed to obtain the strain sensing wrapped yarn.

[0087] Comparative Example 2

[0088] The same as Example 1, except that step (II) is omitted, specifically:

[0089] (I) take the spandex elastic core yarn as the core layer, feed it into the hollow spindle package wrapping spinning machine through the active feeding roller, apply a certain multiple of the pre-draft, guide it to the lower hollow spindle center tube of the hollow spindle package wrapping spinning machine after the warp guide guide hook, and guide it out from the upper end of the lower hollow spindle center tube; the silver-plated filament nested on the lower hollow spindle and the upper hollow spindle is cross-wrapped on the surface of the elastic core yarn in a tight state, forming a cross-wrapping structure, and then the bidirectional pre-wrapped yarn of the cross-wrapped elastic core yarn is wound on the bobbin through the guide roller and the traverse guide hook, to obtain the bidirectional pre-wrapped yarn;

[0090] (II) take the bidirectional pre-wrapped yarn as the core layer, feed it into the upper hollow spindle center tube of the hollow spindle package wrapping spinning machine again, wrap the basalt fiber nested on the upper hollow spindle on the surface of the bidirectional pre-wrapped yarn, to obtain a multi-level structure, a strain sensing wrapped yarn for underwater and fire rescue scenes.

[0091] Performance test

[0092] The strain sensing performance of the strain sensing wrapped yarn of the embodiment of the present application is shown in Table 1.

[0093] The two ends of the prepared strain sensing wrapped yarn are pasted with conductive copper sheets as electrodes, and are fixed at the joints of the human body (such as fingers, wrists or elbows). Then, the copper sheet electrodes are connected to the LinkZill-01RC portable resistance measurement system through wires to monitor and record the dynamic data of the resistance change rate of the wrapped yarn in the joint bending process in real time.

[0094] The appearance of the strain sensing wrapped yarn for underwater and fire rescue scenes prepared in Example 1 of the present application is shown in Figure 3 It can be seen that the yarn body surface is tightly and uniformly wrapped with basalt fiber, and this structure can effectively block open flames, providing a good protective barrier for a certain length of burning.

[0095] The multi-level structure design of the strain sensing wrapped yarn in Example 1 of the present application and the corresponding physical diagrams of each step (I, II, III) are shown in Figure 4 , wherein (a) is the bidirectional pre-wrapped yarn of the silver-plated filament cross-wrapped elastic core yarn; (b) is the bidirectional pre-wrapped yarn of the elastic hose nested structure; (c) is the multi-level structure strain sensing wrapped yarn.

[0096] The stress-strain curves obtained by 100 cycle tensile tests of the strain sensing wrapped yarn of Example 1 of the present application under (a) 100% tensile strain and (c) 150% tensile strain, respectively; (b) and (d) are the change trend curves of the tensile mechanical peak value with the number of cycles under the corresponding strain conditions, and the insert is a local enlarged view of the mechanical peak value in a certain time period. Taking the 100% tensile strain of the wrapped yarn as an example, Figure 5The test results in the middle (a-b) show that the wrapping yarn has excellent fatigue resistance and service stability. Specifically, in addition to adaptive deformation in the first cycle due to structure adjustment, the mechanical curve hysteresis loop area tends to be consistent in each cycle thereafter; at the same time, the tensile mechanical peak value tends to be stable rapidly with the increase of cycle number. The above data collectively confirm that the prepared strain sensing wrapping yarn can maintain a highly consistent mechanical response under long-term large strain load, has high structural reliability, and has excellent long-term service stability. This feature ensures that it can maintain a long-term reliable service life when repeatedly experiencing tensile deformation in the rescue process. Figure 5 (c-d) are the corresponding test results of the wrapping yarn under a tensile strain of 150%, and the analysis idea is basically the same, which will not be repeated here.

[0097] The comparison chart of the strain sensing wrapping yarn prepared in Example 1 of the present application in the underwater environment before (a) and after (b) finger bending is shown in Figure 6 . When testing the underwater strain sensing behavior of the strain sensing wrapping yarn, the finger is immersed in water (corresponding to Figure 6 the initial state shown in (a)), and is bent to Figure 6 the state shown in (a). This process is a complete finger bending cycle.

[0098] Figure 7 The strain sensing wrapping yarn prepared in Example 1 of the present application (a) shows scattered sparks sputtering when burning under open flame; (b) shows the color change of the local surface of the wrapping yarn after burning for 10 seconds; the inner elastic hose can be seen after peeling off the outermost basalt fiber after (c) 5 seconds and (d) 10 seconds of burning. As shown in Figure 7 , the strain sensing wrapping yarn only shows scattered sparks sputtering during the open flame burning process, and no sustained combustion phenomenon occurs. Figure 7 (b) shows the surface morphology of the yarn body after burning for 10 seconds, and it can be seen that the surface color of the burning area is deepened, but the overall structure still maintains regularity. Figure 7 (c) shows that after the wrapping yarn is burned under open flame for 5 seconds, the inner elastic hose peeled off the outermost basalt shows no obvious damage; and after burning for 10 seconds (d) Figure 7 ), a slight ablation line appears on the surface of the elastic hose.

[0099] Figure 8 The resistance change of the strain sensing wrapping yarn prepared in Example 1 of the present application before and after finger bending under different working conditions: (a) in air; (b) underwater; (c) after burning for 10 seconds under open flame. It can be seen that the strain sensing wrapping yarn can maintain stable tensile electrical response after being in air, underwater environment and burning for 10 seconds under open flame, and shows reliable strain sensing performance.

[0100] Figure 9The figures for Comparative Example 1 show the burning behavior of the strain-sensing coated yarn containing only an inner elastic tube after being directly burned by a lighter for several seconds. (a) represents 0 s, (b) 2 s, (c) 4 s, and (d) 6 s. It can be seen that due to the lack of a physical barrier of the outermost basalt fiber, the strain-sensing coated yarn has insufficient fire resistance. The experiment shows that after being directly burned by a lighter for 4 seconds, the outer elastic tube of the coated yarn is ignited and quickly combusts, causing the sensor structure to fail and the strain monitoring function to be lost.

[0101] Figure 10 The resistance change rate of the silver-plated filament component used in the preparation of the strain-sensing coated yarn for Comparative Example 2 after being placed in air for 30 seconds and then immersed in water is shown in the figure. As shown, during the 30-second period in air, the resistance change rate of the silver-plated filament is almost zero, exhibiting excellent conductivity stability. However, when placed underwater, the resistance change rate immediately becomes erratic and fluctuates wildly. The main mechanism is that the penetration and adsorption of water vapor not only triggers electrolytic corrosion and oxidation of the silver plating layer but may also form additional leakage paths between the filaments, leading to a significant increase in resistance and a sharp decline in conductivity. It can be inferred that due to the lack of effective protection from the elastic flexible hose sealing layer, the prepared strain-sensing coated yarn will also exhibit chaotic resistance changes in an underwater environment, causing the monitoring function to fail.

[0102] Figure 11 The images show the morphology of the strain-sensing coated yarn prepared in Example 2 of this invention (a) and after direct burning for 10 seconds (b). It can be seen that the prepared strain-sensing coated yarn has excellent fire resistance. The surface of the coated yarn is uniformly coated with basalt fibers. Figure 11 (a) After being directly burned for 10 seconds, its overall structural morphology was not significantly affected, and the only visible damage was a darkening of the surface color of the burned area. Figure 11 (b)

[0103] Figure 12 The images show the morphology of the strain-sensing coated yarn prepared in Example 3 of this invention (a) and after direct burning for 10 seconds (b). It can be seen that the prepared strain-sensing coated yarn has excellent fire resistance. The surface of the coated yarn is uniformly coated with basalt fibers. Figure 12 (a) After being directly burned for 10 seconds, its overall structural morphology was not significantly affected, and the only visible damage was a darkening of the surface color of the burned area. Figure 12 (b)

[0104] Figure 13 The images show the morphology of the strain-sensing coated yarn prepared in Example 4 of this invention (a) and after direct burning for 10 seconds (b). It can be seen that the prepared strain-sensing coated yarn has excellent fire resistance. The surface of the coated yarn is uniformly coated with basalt fibers.Figure 13 In the middle a); after direct burning for 10 seconds, its overall structure morphology is not obviously affected, and the appearance damage only reflects that the surface color of the burning area is darkened Figure 13 In the middle b).

[0105] As can be seen from the above, the processing method is simple and practical, and a strain sensing covered yarn with excellent mechanical soft elasticity, structural stability and strong flame-retardant and heat-insulating performance can be prepared through the synergistic cooperation of the hollow spindle wrapping spinning device and the nesting process. The material still maintains the stable mechanical stability (excellent fatigue resistance) after 100 cycles under large tensile strain (such as 100%, 150% and the like); in terms of flame-retardant and heat-insulating performance, after local burning for 5 seconds by a lighter, the outermost basalt fiber structure is complete, and the inner elastic hose is not damaged; after burning for 10 seconds, the basalt fiber still maintains the structural integrity, and only the inner elastic hose appears slight ablation. In addition, the covered yarn can realize stable and reliable strain monitoring under multiple scene complex working conditions such as air, underwater environment and short-time burning, and is especially suitable for underwater and fire rescue and the like extreme environments.

[0106] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A strain-sensing covering yarn for underwater and fire rescue scenarios, characterized in that, From the inside out, it consists of an elastic core filament, a cross-wound silver-plated filament layer, an elastic flexible tube nesting layer, and a basalt fiber coating layer.

2. The strain sensing covering yarn for underwater and fire rescue scenarios according to claim 1, characterized in that, The fineness of the elastic core wire is 420D to 1680D.

3. The strain sensing covering yarn for underwater and fire rescue scenarios according to claim 1, characterized in that, The fineness of the silver-plated filaments in the cross-wrap type silver-plated filament layer is 20D to 400D.

4. The strain sensing covering yarn for underwater and fire rescue scenarios according to claim 1, characterized in that, The material of the flexible hose is any one of silicone rubber, styrene-butadiene rubber, and fluororubber; the inner diameter of the flexible hose is 0.3mm to 2.0mm, and the outer diameter is 0.8mm to 6.0mm.

5. The strain sensing covering yarn for underwater and fire rescue scenarios according to claim 1, characterized in that, The fineness of the basalt fibers in the basalt fiber coating layer is 0.15 mm to 0.35 mm.

6. A method for preparing strain-sensing coated yarn for underwater and fire rescue scenarios as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) The elastic core yarn is used as the core layer and fed into the hollow spindle winding spinning machine through the active feed roller. After passing through the yarn guide hook, it is introduced into the lower hollow spindle center tube of the hollow spindle winding spinning machine and led out from the upper end of the lower hollow spindle center tube. The silver-plated filaments nested on the lower and upper hollow spindles are sequentially cross-wrapped on the surface of the elastic core yarn. Then, through the yarn guide roller and the transverse yarn guide hook, the bidirectional pre-wrapped yarn with the silver-plated filaments cross-wrapped on the elastic core yarn is wound onto the yarn bobbin to obtain the bidirectional pre-wrapped yarn. (2) The elastic tube is nested on the surface of the bidirectional pre-coated yarn to form a bidirectional pre-coated yarn with an elastic tube nesting structure; (3) The bidirectional pre-coated yarn of the elastic hose nested structure is used as the core layer and fed into the upper hollow spindle center tube of the hollow spindle wrapping spinning machine again. The basalt fiber nested on the upper hollow spindle is wrapped on the surface of the bidirectional pre-coated yarn of the elastic hose nested structure to obtain the strain sensing coated yarn for underwater and fire rescue scenarios.

7. The method for preparing strain-sensing coated yarn for underwater and fire rescue scenarios according to claim 6, characterized in that, In step (1), the pre-stretch ratio of the elastic core wire is 1.5 to 4.

5.

8. The method for preparing strain-sensing coated yarn for underwater and fire rescue scenarios according to claim 6, characterized in that, In step (1), the silver-plated filaments on the lower and upper hollow ingots are wound in opposite directions, forming a cross-spiral structure, with a wrapping twist of 300 to 1800 twists / meter.

9. The method for preparing strain-sensing coated yarn for underwater and fire rescue scenarios according to claim 6, characterized in that, In step (3), the basalt fiber wrapping twist direction is either Z twist or S twist; the basalt fiber wrapping twist is 1000 to 3000 twists / meter.

10. The application of strain-sensing covering yarn as described in any one of claims 1 to 5 in underwater and fire rescue scenarios.

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