Method for testing non-destructive heat retention property of clothes

Abstract

The invention discloses a method for testing the non-destructive heat retention property of clothes, and belongs to the technical field of textile detection. According to the method, a flexible liner is arranged on the inner side of to-be-tested clothes to simulate a human body heat source, the flexible liner is composed of a plurality of independent air chambers, and the flexible liner is evenly attached to the inner surface of the clothes under set contact pressure after being inflated; placing the clothes in an environment simulation cabin, sealing an opening part, heating a flexible liner to a preset initial temperature, then starting a cooling process, and recording temperature change data; and calculating the heat preservation rate of the to-be-detected clothes by combining pre-calibrated background heat loss data of the flexible liner. The method can accurately simulate the real contact state of the human body and the clothes, realizes accurate control of contact pressure and uniform distribution of a thermal field, effectively eliminates test errors caused by poor contact, uneven pressure and other factors in a traditional test method, has the advantages of high test precision, good repeatability, wide application range and the like, and is suitable for popularization and application. And a scientific basis is provided for design, production and purchase of clothes.

Description

Technical Field

[0001] This invention relates to the field of textile testing technology, and in particular to a non-destructive method for testing the warmth retention of clothing. Background Technology

[0002] With the continuous advancement of functional textile testing technology, non-destructive testing methods for the thermal insulation performance of clothing have become a key means of evaluating the thermal protection capabilities of winter clothing. Traditional thermal insulation tests often employ flat-plate hot plate apparatus or heated mannequin systems. The former struggles to simulate the three-dimensional structure and air layer distribution of clothing under actual wearing conditions, while the latter is costly, complex to operate, and poorly suited for lightweight or fluffy fabrics. Especially in the testing of high-loft garments such as down jackets, accurately quantifying their overall thermal resistance and insulation rate without disturbing the internal static air layers has become a core challenge facing current testing technologies.

[0003] One proposed method is the experimental chamber method based on built-in heat sources and temperature sensors to simulate the heat dissipation process of the human body. This method indirectly reflects the thermal insulation performance of the material by arranging heating elements inside the clothing and monitoring their cooling rate. However, existing solutions directly fix rigid heat sources such as steel balls and sensors to the inside of down jackets, resulting in localized pressure concentration, compressing the fluffy down structure, significantly altering the original air layer thickness, and causing test results to deviate from actual wearing conditions. Furthermore, the discrete arrangement of heat sources makes it difficult to form a continuous and uniform temperature field, failing to effectively simulate the approximately isothermal thermal radiation characteristics of the human body surface, leading to insufficient representativeness of multi-point measurement data and systematic bias in the overall thermal insulation performance assessment.

[0004] Therefore, it is necessary to propose a non-destructive thermal insulation testing method for clothing to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a non-destructive method for testing the warmth retention of clothing.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a non-destructive method for testing the thermal insulation properties of clothing, comprising the following steps:

[0007] A flexible pad is placed inside the garment to be tested. The flexible pad is an inflatable flexible device used to simulate the human body's heat source.

[0008] Gas is introduced into the independent air chamber, so that the flexible pad is uniformly attached to the inner surface of the garment to be tested at a set contact pressure;

[0009] The garment to be tested was placed in an environmental simulation chamber, and all openings of the garment were sealed.

[0010] The flexible pad is heated to a preset initial temperature;

[0011] Set target environmental parameters in the environmental simulation chamber, start the cooling process, and record the time required for the average surface temperature of the flexible pad to drop from the initial temperature to the preset termination temperature, or record the decrease value of the average surface temperature of the flexible pad within a fixed time interval.

[0012] The heat retention rate of the garment under test is calculated by combining the pre-calibrated background heat loss data of the flexible pad.

[0013] In a preferred embodiment of the present invention, the flexible pad is in the form of a three-dimensional curved surface, the outline of which matches the outline of the standard human upper body, and includes at least one functional area among the front chest area, back area, left shoulder area, right shoulder area and underarm transition area, each of the functional areas being composed of a plurality of independent air chambers.

[0014] In a preferred embodiment of the present invention, the independent air chamber is formed by heat sealing two layers of elastic thin film material, and the planar projected area of ​​each independent air chamber is 8 cm². 2 ~15cm 2 The maximum expansion height after inflation is ≤2cm.

[0015] In a preferred embodiment of the present invention, the set contact pressure is ≤0.5kPa.

[0016] In a preferred embodiment of the present invention, the method for uniformly adhering the flexible pad to the inner surface of the garment to be tested includes:

[0017] Each of the independent air chambers is simultaneously inflated to the initial pressure to achieve pre-fitting;

[0018] Based on the feedback from the pressure sensor installed on the outer surface of each independent air chamber, the air pressure of each independent air chamber is adjusted by an independent control method so that the contact pressure between each independent air chamber and the inner surface of the garment under test is stabilized near the target set value.

[0019] Calculate the standard deviation of the contact pressure of all the independent air chambers. If the standard deviation exceeds the threshold, fine-tune the independent air chambers with abnormal pressure until the uniformity requirement is met.

[0020] In a preferred embodiment of the present invention, the heating method of the flexible pad includes: real-time monitoring of the data of the surface temperature sensor array of the flexible pad, and determining that the thermal field uniformity meets the standard when the average surface temperature reaches the initial temperature and the standard deviation of the temperature distribution is less than 0.3℃.

[0021] In a preferred embodiment of the present invention, the method for calculating the heat preservation rate includes:

[0022] Under blank conditions, the cumulative heat loss of the flexible pad was tested as it decreased from the initial temperature to the final temperature. And calculate the equivalent heat capacity;

[0023] The flexible pad was wrapped with a standard garment of known thermal resistance, and the cumulative heat loss was tested. And calculate the heat retention rate of the standard sample garment. ;

[0024] Test the heat loss of the garment under test ;

[0025] Calculate the heat retention rate of the garment to be tested. : .

[0026] In a preferred embodiment of the present invention, the method further includes fitting the temperature-time data of the cooling process with an exponential decay curve to obtain the thermal time constant of the garment under test, which serves as an auxiliary evaluation index for its thermal insulation performance.

[0027] In a preferred embodiment of the present invention, each independent air chamber of the flexible liner is embedded with a micro heating element, and the outer surface is integrated with a distributed temperature sensor array.

[0028] In a preferred embodiment of the present invention, the garment to be tested is a garment containing a high-loft heat-insulating filling material.

[0029] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0030] (1) This invention constructs a complete non-destructive thermal insulation testing method for clothing by combining flexible pad design, air chamber pressure control, distributed temperature monitoring, and calibration calculation methods. This method can simulate the actual contact state between the human body heat source and clothing, achieving precise control of contact pressure and uniform distribution of the heat field, effectively eliminating test errors caused by factors such as poor contact, uneven pressure, and uneven heat field in traditional testing methods. At the same time, through calibration calculation and thermal time constant analysis, more accurate and reliable thermal insulation performance data can be obtained, providing a scientific basis for the design, production, and selection of thermal clothing.

[0031] (2) This invention designs the flexible pad into a three-dimensional curved surface that matches the contour of the standard human upper body and divides it into multiple functional areas composed of several independent air chambers. This allows the flexible pad to better simulate the human body shape and, after inflation, to form a more fitting and uniform contact with the inner surface of the garment being tested. Compared to the use of a flat heat source in existing technologies, the flexible pad design improves the fit and uniformity of the heat source and garment contact during testing, avoiding local thermal resistance test deviations caused by poor contact, thereby improving the accuracy and reliability of the test results. At the same time, the partitioned design also allows the flexible pad to adapt to the complex structure of different styles of garments, expanding the applicability of the testing method.

[0032] (3) The flexible pad of the present invention is configured with multiple independent air chambers and uses pressure sensors to monitor the contact pressure between each air chamber and the inner surface of the garment in real time. Based on the feedback signal, the air pressure of each air chamber is independently adjusted to stabilize the contact pressure near the target set value, and the uniformity is judged by calculating the standard deviation. This active control method can ensure that the flexible pad forms a uniform and stable contact state with the inner surface of the garment to be tested, effectively eliminating the test error caused by uneven contact pressure in traditional test methods, improving the repeatability and consistency of the test, and providing comparable test conditions for different batches and styles of garments.

[0033] (4) By setting micro heating elements and a distributed temperature sensor array in the flexible pad, the present invention can heat the flexible pad to a preset initial temperature and monitor its surface temperature distribution in real time. When the average surface temperature reaches the initial temperature and the standard deviation of the temperature distribution is less than the threshold, the uniformity of the thermal field is determined to be up to standard, which ensures the temperature uniformity and stability of the heat source during the test and avoids test errors caused by uneven thermal field.

[0034] (5) This invention calibrates the flexible pad by testing its heat loss under blank conditions, using a standard garment with known thermal resistance, and then tests the heat loss of the garment under test to calculate the insulation rate. This calibration method eliminates the influence of the heat loss of the flexible pad itself, making the test results more accurate. Compared with the prior art that directly measures temperature changes or uses simple calculation methods, this feature considers the heat loss of the test medium itself, and achieves standardization and comparability of test results through the calibration process, making the test results from different laboratories and at different time periods have good consistency, providing a reliable basis for the objective evaluation of the thermal insulation performance of clothing. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a simplified diagram of the thermal insulation testing system of the present invention;

[0037] Figure 2 This is a schematic diagram of the flexible pad of the present invention;

[0038] In the diagram: 1. Flexible padding; 11. Front chest area; 12. Left shoulder area; 13. Right shoulder area; 14. Underarm transition area; 2. Environmental simulation chamber; 3. Auxiliary support; 4. Air pump; 5. Temperature control module. Detailed Implementation

[0039] In applications such as high-end outdoor apparel, polar equipment, and special protective clothing, there is an urgent need for non-destructive, repeatable, and high-fidelity thermal insulation testing methods. Existing technologies mainly follow two routes: one is based on a thermal mannequin, which can simulate the human body's thermophysiological response, but is costly, complex to operate, and difficult to standardize; the other is based on a point-source rigid heat source method (such as a steel ball heat source) in an experimental chamber, which monitors the cooling rate of the heat source to inversely determine thermal insulation performance. While this method simplifies the equipment, it contains inherent structural defects.

[0040] While pursuing a "non-destructive" appearance, existing methods actually involve "structural intrusion"—the weight of the rigid heat source compresses the high-loft filling material (such as down), disturbing its microscopic air layer structure and causing distortion in thermal resistance measurements. Simultaneously, discrete point heat sources cannot simulate the continuous isothermal surface characteristics of human skin, introducing thermal field inhomogeneity bias. A comparison of the advantages and disadvantages of different technical approaches shows that while the warm-body dummy method is realistic, its practicality is low, while the traditional experimental chamber method is efficient but lacks accuracy, especially when dealing with high-loft filled clothing, where systematic errors are significant. This has become a typical unresolved problem in the industry, hindering the reliability of product development and quality control.

[0041] This invention addresses the structural intrusion problem in testing high-loft clothing by employing a flexible, integrated air-heat pad design and air pressure feedback control. Specifically, a flexible pad, simulating a human body heat source, is composed of multiple independent air chambers, housing micro-heating elements and a distributed temperature sensor array. Precise air pressure regulation ensures the flexible pad adheres to the garment's lining with a contact pressure of ≤0.5 kPa, preventing compression of the filling structure. Combined with boundary condition control of the environmental simulation chamber and calibration of the system's background heat loss, the invention recreates a realistic heat exchange environment, improving testing accuracy and compatibility. This provides the industry with a high-fidelity, non-invasive, and repeatable method for evaluating thermal insulation performance.

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0045] Example 1:

[0046] Figure 1 A simplified diagram of the thermal insulation testing system of the present invention is shown.

[0047] This embodiment provides a non-destructive method for testing the thermal insulation properties of clothing, using the aforementioned thermal insulation testing system. The method includes the following steps: S1, placing a flexible pad 1 inside the clothing to be tested. The flexible pad 1 is an inflatable flexible device used to simulate a human body heat source; S2, inflating an independent air chamber to allow the flexible pad 1 to uniformly adhere to the inner surface of the clothing to be tested at a set contact pressure; S3, placing the clothing to be tested in an environmental simulation chamber 2 and sealing all openings of the clothing; S4, heating the flexible pad 1 to a preset initial temperature; S5, setting target environmental parameters within the environmental simulation chamber 2, initiating a cooling process, and recording the time required for the average surface temperature of the flexible pad 1 to drop from the initial temperature to a preset termination temperature, or recording the decrease in the average surface temperature of the flexible pad 1 at fixed time intervals; S6, calculating the thermal insulation rate of the clothing to be tested by combining pre-calibrated background heat loss data of the flexible pad 1.

[0048] The specific challenges and key issues faced by this invention in implementing the above steps are: how to construct a flexible heat source system that can both simulate the continuous and uniform characteristics of a human body heat source and completely avoid disturbing the high-fluff filling structure. First, the flexible pad 1 needs to avoid any mechanical loading at the microscale, but the weight of the flexible pad 1 itself, the distribution of heating elements, and the inflation process can all cause localized stress concentration, leading to the compression of low-density materials such as down. Second, the requirements for thermal field uniformity control are extremely high; if there are temperature differences or uneven bonding between independent air chambers, it will distort the thermal boundary conditions and introduce measurement errors. Furthermore, the air pressure feedback system needs to achieve independent dynamic stability of multiple air chambers, but gas compressibility, material creep, and environmental fluctuations can easily lead to pressure runaway. The essence of these challenges is the technical gap between the concept of "stress-free bonding" and a feasible engineering solution, involving the integration of multiple disciplines such as precision mechanical design, thermodynamic modeling, control algorithms, and sensor fusion. The inventors have overcome these gaps through innovations such as modular air chamber layout and PID closed-loop control, demonstrating the maturity and feasibility of the solution.

[0049] The overall process of the thermal insulation test of the present invention is as follows: stress-free bonding is achieved by inserting a flexible pad 1 and driving it with air pressure; stable boundary conditions are set in an environmental simulation chamber 2; a heating-cooling cycle is executed; and the thermal insulation rate is calculated based on the calibration data.

[0050] The following section details each step of the heat retention test method.

[0051] In step S1, a flexible pad 1 is placed inside the garment to be tested. The flexible pad 1 is an inflatable flexible device used to simulate the human body's heat source.

[0052] It should be noted that the garments to be tested refer to clothing products whose warmth retention performance needs to be tested, such as down jackets, cotton-padded jackets, or other filled garments. These garments contain high-loft insulation materials (such as down or synthetic fiber cotton), which achieve warmth through trapped air. During testing, the garments should be in an intact and undamaged state, without any tears or deformation, to ensure the representativeness of the test. The inside refers to the inner surface area of ​​the garment that comes into contact with the human skin when worn.

[0053] like Figure 2 As shown, the flexible pad 1 is an inflatable flexible device used to simulate a human body heat source. The flexible pad 1 is made of elastic material and contains multiple independent air chambers, each of which can be individually inflated and controlled.

[0054] Furthermore, the overall design of the flexible pad 1 is based on ergonomic principles, with its three-dimensional curved surface strictly matching the geometry of the inner surface of the standard human upper torso. The flexible pad 1 is divided into five functional areas: the front chest area 11, the back area, the left shoulder area 12, the right shoulder area 13, and the underarm transition area 14. The back area is essentially consistent with the front chest area 11 (not shown in the figure). The heat flux density varies significantly between different areas, and the zoning simulates real heat distribution. Each functional area consists of several independent air chamber units. The entire flexible pad 1 contains 12 to 24 independent air chambers, physically isolated by a flexible diaphragm, which are not interconnected. This flexible diaphragm is heat-sealed from the same elastic thin film material as the main body of the flexible pad 1, ensuring no gas flow between the air chambers, but allowing for overall bending.

[0055] Each independent air chamber is formed by heat-sealing two layers of elastic film material to create a closed cavity. The elastic film material is a medical-grade silicone composite membrane with a thickness of 0.1–0.2 mm. The planar projected area of ​​each independent air chamber is 8 cm². 2 ~15cm 2 (For example, the 11 air chambers in the anterior chest region have a relatively large area, approximately 12 cm.) 2 The armpit area is relatively small, about 8cm. 2 In the uninflated state, the height of the independent air chamber is 3-5mm; after inflation, the maximum expansion height is ≤20mm, to accommodate the internal space of clothing of different thicknesses (such as thin jackets and thick down jackets).

[0056] Each individual air chamber contains at least one miniature heating element. This miniature heating element is a flexible polyimide (PI)-based thin-film heating element. A serpentine resistance circuit is formed on the surface of the PI substrate using a laser etching process to ensure heating uniformity. The width, spacing, and total length of the serpentine circuit are dynamically adjusted according to the area of ​​the individual air chamber, for example, 10 cm. 2 The air chamber corresponds to a line length of approximately 1.2m and a resistance of 5Ω. The electrodes of the miniature heating element are connected to an electrical interface located in the neck region of the flexible pad 1.

[0057] Furthermore, the outer surface of the flexible pad 1, that is, the side that directly contacts the inner surface of the garment to be tested, integrates a temperature sensor array. Each independent air chamber area has 2 to 4 temperature sensors arranged at equal intervals.

[0058] It is worth noting that the manufacturing method of the flexible pad 1 includes:

[0059] The liner surface model was designed using 3D software and divided into air cell units;

[0060] A multi-layer hot-pressing process is used to heat-seal the upper and lower layers of silicone composite film with the middle partition film to form an air chamber.

[0061] The heating element and sensor are embedded in the air chamber using automated mounting technology.

[0062] It should be noted that the placement of the flexible pad 1 into the garment under test must be performed outside the environmental simulation chamber 2 to avoid space constraints inside the chamber. The specific operating steps are as follows: suspend the uninflated flexible pad 1 on the auxiliary support 3, with the flexible pad 1 hanging naturally; inspect the garment under test to ensure it is undamaged; suspend the garment under test outside the auxiliary support 3 and the flexible pad 1, maintaining a natural hanging state, and ensure that the functional areas of the flexible pad 1 are aligned with the corresponding areas of the garment under test, ensuring there are no wrinkles or twists.

[0063] In step S2, gas is injected into the independent air chamber so that the flexible pad 1 is evenly attached to the inner surface of the garment to be tested at a set contact pressure.

[0064] It should be noted that the gas refers to the medium filled into each independent gas chamber, which is either dry air or nitrogen, preferably dry air, as it is low in cost and has no chemical impact. The contact pressure refers to the pressure per unit area between the flexible pad 1 and the inner surface of the garment. The contact pressure between the flexible pad 1 and the inner surface of the garment to be tested is set to ≤0.5 kPa. This value has been experimentally determined to be lower than the compression yield threshold of fillings such as down, ensuring no substantial compression.

[0065] Furthermore, each independent air chamber is equipped with a piezoresistive MEMS pressure sensor on its outer surface, which is the side that contacts the inner surface of the garment being tested.

[0066] In this step, gas is injected into each independent air chamber by an externally installed air pump 4; by monitoring and controlling the contact pressure between each independent air chamber and the inner surface of the garment to be tested between 0.1 and 0.5 kPa, the flexible pad 1 is uniformly attached to the inner surface of the garment to be tested.

[0067] In step S3, the garment to be tested is placed inside the environmental simulation chamber 2, and all openings of the garment are sealed.

[0068] It should be noted that the environmental simulation chamber 2 is a sealed enclosure used to simulate external environmental conditions (temperature, humidity, wind speed). The environmental simulation chamber 2 uses conventional technology and its implementation methods have been standardized, so it will be summarized briefly.

[0069] Specifically, the garment to be tested, along with the auxiliary support 3 and the flexible pad 1, is transferred into the environmental simulation chamber 2 and fixed in the designated position. Elastic silicone sealing rings are then used to tighten the cuffs, hem, and collar of the garment to prevent wind from the environmental simulation chamber 2 from entering the interior of the garment.

[0070] In step S4, the flexible pad 1 is heated to a preset initial temperature.

[0071] Specifically, the external temperature control module 5 activates the micro heating elements installed inside each independent air chamber to heat the flexible pad 1 to a preset initial temperature. initial temperature The preferred setting is 35.0℃.

[0072] Furthermore, the heating method for the flexible pad 1 includes the following steps:

[0073] Step S41: During the heating process, monitor the data from multiple monitoring points of the temperature sensor array on the surface of the flexible pad 1 in real time, and calculate the average temperature of the entire surface of the flexible pad 1. and temperature distribution standard deviation .

[0074] Step S42, when the average temperature Reaching the initial temperature And the standard deviation of temperature distribution When the uniformity of the thermal field is deemed to meet the standard, the heat preservation stage begins.

[0075] The heating steps described above ensured a high degree of consistency in thermal boundary conditions at the start of the test.

[0076] In step S5, the target environmental parameters are set in the environmental simulation chamber 2, the cooling process is started, and the time required for the average surface temperature of the flexible pad 1 to drop from the initial temperature to the preset termination temperature is recorded, or the decrease value of the average surface temperature of the flexible pad 1 is recorded within a fixed time interval.

[0077] Specifically, the target environmental parameters are set according to the testing requirements, such as: ambient temperature. Temperature: -5.0±0.2℃, Relative Humidity (RH): 50±3%, Wind Speed: The value is 1.0 ± 0.1 m / s. This environmental parameter is controlled collaboratively by the cooling / heating unit, humidification / dehumidification module, and adjustable-speed centrifugal fan integrated within the environmental simulation chamber 2.

[0078] After the environmental parameters inside the environmental simulation chamber 2 stabilize, the power supply to all micro heating elements on the flexible liner 1 is turned off, and the passive cooling process is initiated.

[0079] Furthermore, during the cooling process, temperature monitoring data from the temperature sensor array is acquired in real time, and the average surface temperature of the flexible pad 1 is calculated in real time. The cooling process continues until... Reduced to the preset termination temperature Record the time required. It is important to note that during the cooling process, environmental parameters... RH or If the test deviates from the set range, it must be stopped.

[0080] As an alternative, it can also be done at fixed time intervals. Internal record of average temperature drop Used for rapid evaluation.

[0081] In step S6, the heat retention rate of the garment under test is calculated by combining the background heat loss data of the pre-calibrated flexible pad 1.

[0082] Specifically, the method for calculating the heat retention rate of the garment under test includes the following steps:

[0083] Step S61: Under blank test conditions, i.e., without any clothing covering the flexible pad 1, perform the heating-cooling cycle according to steps S4 and S5, and record the temperature from the initial temperature. Reduced to the termination temperature Time required The cumulative heat loss during this process is calculated using Newton's law of cooling. : Where A is the effective heat dissipation area of ​​flexible pad 1. for and The average value, The comprehensive convective heat transfer coefficient under current environmental conditions depends on the ambient wind speed and temperature, and needs to be recalibrated after each change in environmental conditions; calculate the equivalent heat capacity parameters of flexible pad 1: .

[0084] Step S62: Use thermal resistance value A known standard thermal garment is wrapped with a flexible pad 1. The same procedure is repeated, and the temperature is recorded from... Down to time And calculate the cumulative heat loss. : The cumulative heat loss of the garment under test was calculated using the same method. : Meanwhile, according to the formula Calculate the known insulation rate of the standard sample ,in For the thermal resistance of the air layer, a standard value of 0.15 m is used. 2 ·K / W.

[0085] Step S63: Substitute the data obtained in steps S61 and S62 into the formula. The heat retention rate of the garment under test was calculated. .

[0086] Furthermore, to improve the sensitivity of the thermal insulation test, an exponential decay curve was fitted to the temperature-time data during the cooling phase: The thermal time constant of the garment under test was obtained by fitting using the nonlinear least squares method. The calculated thermal time constant Thermal time constant of the standard sample By comparing the values, the ratio can serve as an auxiliary evaluation index for thermal insulation performance, making it suitable for rapid screening of scenarios.

[0087] Example 2:

[0088] As a preferred variation of the present invention, this embodiment further refines the bonding method in step S2 of the test method in embodiment 1 to ensure that the flexible pad 1 is uniformly bonded to the inner surface of the garment to be tested.

[0089] The method for bonding the flexible pad 1 to the inner surface of the garment to be tested in step S2 includes the following steps:

[0090] Step S21: Through the external air pump 4 and the air filling pipes connected to each independent air chamber, gas is synchronously injected into all independent air chambers, so that the internal pressure of each independent air chamber quickly reaches the preset initial pressure. (Optional 0.6~1kPa), and maintain this pressure state. Seconds. This step allows the flexible pad 1 to fully expand under internal pressure, overcoming the material's own bending stiffness and the static friction between it and the inner surface of the garment to be tested, achieving preliminary pre-adhesion with the large curvature inner surface.

[0091] Step S22: After pre-bonding is completed, set the target contact pressure. For each individual air chamber, based on the contact pressure value monitored in real time by the piezoresistive MEMS pressure sensor installed on the surface, a PID control algorithm is used to independently adjust the air intake or exhaust volume to that individual air chamber until the contact pressure corresponding to all individual air chambers stabilizes within the allowable fluctuation range and maintains this stable state. Minutes are needed to eliminate the creep effect of the flexible pad material under continuous load and ensure the long-term stability of contact pressure.

[0092] Step S23: Under the steady-state condition of step S22, collect the instantaneous values ​​of the baseline pressure on the surface of all independent air chambers. Calculate the average value and standard deviation .

[0093] Step S24: Set the uniformity judgment threshold ;

[0094] like Once it is determined that the flexible pad 1 and the inner surface of the garment to be tested have achieved a uniform fit, subsequent testing steps can be carried out.

[0095] like This indicates regional poor adhesion and identifies contact pressure deviating from the average value. Exceed Independent air chambers, in Fine-tune the contact pressure within a small range around the target value; after fine-tuning, collect and calculate again. Repeat this judgment and fine-tuning process until the uniformity requirement is met.

[0096] The uniform bonding method in this step, through the concept of statistical process control, elevates uniformity from a qualitative judgment to a quantitative control, significantly improving the reliability and consistency of bonding.

[0097] The following comparative experiment verifies the beneficial effects of the method of the present invention on the warmth retention test of down jackets.

[0098] Five men's down jackets of different sizes were selected as test samples (S1-S5) to cover different filling materials, down fill weights, and fabric combinations. Detailed sample information is shown in the table below:

[0099] Table 1. Detailed information on the test samples

[0100]

[0101] Group 1:

[0102] The flexible pad 1 and environmental simulation chamber 2 of this invention are used. The flexible pad 1 is divided into a front chest area 11 (8 independent air chambers), a back area (8 independent air chambers), left / right shoulder areas 13 (2 independent air chambers each), and an underarm transition area 14 (2 independent air chambers each), for a total of 24 independent air chambers. Each independent air chamber is heat-sealed from a 0.15mm thick medical-grade silicone composite film, with a planar projected area of ​​approximately 10 cm². 2 Each independent air chamber is equipped with a flexible polyimide film heating element, and three PT1000 temperature sensors are integrated on the outer surface in a triangular arrangement.

[0103] The testing steps include:

[0104] 1. Suspend the uninflated flexible pad 1 and the test sample sequentially on the auxiliary support 3, seal all openings, and inflate each independent air chamber with dry air. First, inflate rapidly at a pressure of 0.8 kPa to initially expand the pad, then precisely control the target contact pressure at 0.3 kPa ± 0.02 kPa and maintain it for 5 minutes to ensure that the flexible pad 1 and the inner surface of the sample are uniformly and stress-free.

[0105] 2. Activate all micro heating elements to heat the flexible pad 1 to its initial temperature. It also monitors the temperature at various points on the surface in real time, and when the average surface temperature reaches... And the standard deviation of temperature distribution At that time, thermal equilibrium is determined to have been reached.

[0106] 3. Turn off heating and start the cooling process. The parameters for Environmental Simulation Chamber 2 are set as follows: = -5.0℃, relative humidity RH is 50%, wind speed = 1.0 m / s. Record the average surface temperature of flexible pad 1 from Reduced to the termination temperature Time required to reach 30.0℃ .

[0107] 4. Based on the pre-calibrated system background heat loss data, calculate the heat retention rate of the garment under test according to the formula.

[0108] Group 2:

[0109] The method employing a point-like rigid heat source based on the experimental chamber specifically includes:

[0110] The heat source consists of six solid stainless steel balls with a diameter of 25mm. Each ball has a miniature heating rod and an armored K-type thermocouple embedded in its center. Each ball weighs approximately 75g, and the total weight is approximately 450g.

[0111] The testing steps are as follows:

[0112] 1. Place the test sample flat on a low thermal conductivity plate (PTFE plate) in the experimental chamber. After preheating the 6 steel ball heat sources to 35.0℃, place them directly inside the test sample according to the layout of front chest area 11 (2), back area (2), left shoulder area 12 (1), and right shoulder area 13 (1).

[0113] 2. Seal the experimental chamber and set the environmental parameters to be completely consistent with those of Group 1.

[0114] 3. Record the time required for the average reading of the 6 steel ball temperature sensors to drop from 35.0℃ to 30.0℃, and calculate the heat preservation rate.

[0115] Group 3:

[0116] The test sample was dressed on a heated mannequin, and the ambient temperature in the climate chamber was set to -5.0℃, with a wind speed of 1.0 m / s (consistent with Groups 1 and 2). After the system reached thermal equilibrium, the overall thermal resistance of the garment was directly measured and calculated.

[0117] Each method was used to test 5 samples 3 times, and the average value was taken as the final result. For ease of comparison, the results obtained by the warm body heating method were used. Values ​​are obtained through formulas The results were converted to insulation rate to ensure dimensional uniformity. The test results are shown in the table below:

[0118] Table 2. Comparison of insulation rates obtained by three test methods (unit: %)

[0119]

[0120] To quantify the precision of the test results, the standard deviation (SD) of three repeated tests within each group was calculated, and the correlation coefficient (R²) between each group's method and the warm-body dummy method was also calculated. 2 ( ), to assess its consistency with the benchmark method.

[0121] Table 3. Precision and accuracy analysis of the test method

[0122]

[0123] As shown in Table 2, the results of the method of the present invention (Group 1) and the warm body dummy method (Group 3) are highly consistent, with an average absolute deviation of only 0.72% and a maximum deviation of no more than 0.8%. In contrast, the traditional method (Group 2) systematically and significantly underestimates the warmth retention performance, with an average deviation of 5.3%, especially for the high-loft S3 and S5 samples, where the deviation exceeds 7%. Table 3 shows the R values ​​of the method of the present invention and the benchmark. 2 The result is as high as 0.992, far exceeding the 0.865 of the traditional method. This proves that the present invention achieves accurate testing of the warmth retention of down jackets under the conditions of relatively simple technology and significantly lower cost than warm body mannequins.

[0124] Table 3 shows that the average standard deviation (SD) of the repeatability test of the method of the present invention is only 0.6%, demonstrating excellent precision. This indicates that the fit and thermal field control of the flexible pad 1 are very stable. In contrast, the standard deviation of the traditional experimental chamber method is as high as 2.8%, because the placement of the heat source and its degree of compression of the down are difficult to be completely consistent each time, introducing human operation error and system random error.

[0125] This invention, through a flexible pad 1 and a low contact pressure of 0.3 kPa, perfectly avoids compression of the down's fluffy structure by the testing device, simulating the real state when the human body wears it. In contrast, in traditional methods, steel balls weighing a total of 450g are directly pressed onto the down, severely compacting local filling materials and disrupting the crucial still air layer, leading to distorted measurements of insulation efficiency. The minimal deviation exhibited by this invention, particularly in high-quality down jackets (S3, S5), strongly demonstrates that it solves the core defects of traditional methods.

[0126] In summary, the testing method provided by this invention is comparable to the gold standard warm body dummy method in terms of accuracy and far superior to the traditional experimental chamber method; its precision is significantly higher than that of traditional methods. This invention successfully achieves high-fidelity and repeatable evaluation of the thermal insulation performance of high-loft clothing under completely non-invasive and undisturbed conditions, providing a reliable and practical advanced testing method for industry quality control and new product development.

[0127] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A non-destructive method for testing the thermal insulation properties of clothing, characterized in that, Includes the following steps: A flexible pad is placed inside the garment to be tested. The flexible pad is an inflatable flexible device used to simulate the human body's heat source. Gas is introduced into the independent air chamber, so that the flexible pad is uniformly attached to the inner surface of the garment to be tested at a set contact pressure; The garment to be tested was placed in an environmental simulation chamber, and all openings of the garment were sealed. The flexible pad is heated to a preset initial temperature; Set target environmental parameters in the environmental simulation chamber, start the cooling process, and record the time required for the average surface temperature of the flexible pad to drop from the initial temperature to the preset termination temperature, or record the decrease value of the average surface temperature of the flexible pad within a fixed time interval. The heat retention rate of the garment under test is calculated by combining the pre-calibrated background heat loss data of the flexible pad.

2. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The flexible pad has a three-dimensional curved shape, and its outline matches the outline of the standard human upper body. It includes at least one functional area among the front chest area, back area, left shoulder area, right shoulder area and underarm transition area. Each functional area is composed of several independent air chambers.

3. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The independent air chambers are formed by heat sealing two layers of elastic thin film material, and the planar projected area of ​​each independent air chamber is 8 cm². 2 ~15cm 2 The maximum expansion height after inflation is ≤2cm.

4. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The set contact pressure is ≤0.5kPa.

5. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The method for uniformly adhering the flexible pad to the inner surface of the garment to be tested includes: Each of the independent air chambers is simultaneously inflated to the initial pressure to achieve pre-fitting; Based on the feedback from the pressure sensor installed on the outer surface of each independent air chamber, the air pressure of each independent air chamber is adjusted by an independent control method so that the contact pressure between each independent air chamber and the inner surface of the garment under test is stabilized near the target set value. Calculate the standard deviation of the contact pressure of all the independent air chambers. If the standard deviation exceeds the threshold, fine-tune the independent air chambers with abnormal pressure until the uniformity requirement is met.

6. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The heating method of the flexible pad includes: real-time monitoring of the data of the surface temperature sensor array of the flexible pad, and determining that the thermal field uniformity meets the standard when the average surface temperature reaches the initial temperature and the standard deviation of the temperature distribution is less than 0.3℃.

7. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The method for calculating the insulation rate includes: Under blank conditions, the cumulative heat loss of the flexible pad was tested as it decreased from the initial temperature to the final temperature. And calculate the equivalent heat capacity; The flexible pad was wrapped with a standard garment of known thermal resistance, and the cumulative heat loss was tested. And calculate the heat retention rate of the standard sample garment. ; Test the heat loss of the garment under test ; Calculate the heat retention rate of the garment to be tested. : .

8. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: It also includes fitting the temperature-time data of the cooling process with an exponential decay curve to obtain the thermal time constant of the garment under test, which serves as an auxiliary evaluation index for its thermal insulation performance.

9. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: Each independent chamber of the flexible liner is embedded with a micro heating element, and the outer surface is integrated with a distributed temperature sensor array.

10. The non-destructive thermal insulation testing method for clothing according to claim 1, characterized in that: The garment to be tested is one containing high-loft thermal insulation filling material.

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