A method for testing the fire performance index of low smoke halogen-free materials

Abstract

The application relates to a method for testing a fire performance index of low-smoke halogen-free material and relates to the field of evaluation and testing of low-smoke halogen-free material. According to the fitting of the flame-retardant performance index FRPI and the fire performance index FPI of different standard samples, a linear relationship FRPI-FPI can be obtained, so that only the flame-retardant performance index FRPI of a sample to be tested needs to be obtained, the fire performance index FPI of the sample to be tested can be calculated according to the obtained linear relationship FRPI-FPI, and the evaluation of the flame-retardant performance of the sample to be tested can be realized. The method provided by the application can accurately test the fire performance index of low-smoke halogen-free material by using only a differential scanning calorimeter, the testing process is simplified under the premise of ensuring the testing precision, the testing threshold is reduced, the flame-retardant performance of low-smoke halogen-free material is more conveniently and quickly evaluated, no open flame appears in the whole testing process, the safety coefficient is high, and the method is environment-friendly.

Description

Technical Field

[0001] This application relates to the field of evaluation and testing of low-smoke halogen-free materials, and in particular to a method for testing the fire performance index of low-smoke halogen-free materials. Background Technology

[0002] Currently, low-smoke halogen-free flame retardant materials are widely used as environmentally friendly materials due to their superior flame retardant performance, lack of halogens, low smoke volume during combustion, and low toxicity. Within the ignition time range, the flame retardant material shows a tendency to expand at the ignition location, while the flame extinguishes after ignition. This phenomenon reflects that the flame retardant material has good flammability and poor flame propagation, indicating good flame retardant performance.

[0003] The fire performance index (FPI) directly reflects the flame retardant performance of low-smoke halogen-free flame-retardant materials. The FPI is the ratio of the material's ignition time to the initial peak of its combustion heat release rate, reflecting the material's potential hazard in a fire. In related technologies, a common method for testing the FPI of low-smoke halogen-free flame-retardant materials is using a cone calorimeter. The cone calorimeter can realistically simulate a fire scenario, allowing for quantitative testing of indicators such as ignition time and combustion heat release rate.

[0004] However, cone calorimeters are expensive, have complicated testing procedures, and require specific environmental conditions. Most testing institutions do not have the capability to perform these tests, which causes considerable inconvenience. Summary of the Invention

[0005] This application provides a method for testing the fire performance index of low-smoke halogen-free materials, in order to solve the problems of high testing cost, cumbersome testing process and high requirements for testing environment when using a cone calorimeter to measure the fire performance index of materials in related technologies.

[0006] This application provides a method for testing the fire performance index of low-smoke halogen-free materials, the steps of which include:

[0007] The flame retardant performance index (FRPI) of different standard samples was obtained.

[0008] The fire performance index (FPI) of different standard samples was measured using a cone calorimeter.

[0009] The FRPI and FPI are fitted together to obtain a linear relationship between FRPI and FPI.

[0010] The flame retardant performance index (FRPI) of the sample to be tested is obtained. The fire performance index (FPI) of the sample to be tested is calculated based on the linear relationship between FRPI and FPI and the flame retardant performance index (FRPI) of the sample to be tested. The flame retardant performance of the sample to be tested is evaluated based on the magnitude of the fire performance index (FPI) of the sample to be tested.

[0011] In some embodiments, obtaining the flame retardant performance index (FRPI) of different standard samples includes:

[0012] The heat absorption of different flame-retardant components in different standard samples was obtained respectively;

[0013] Different weights are assigned to the heat absorption of different flame retardant components, and the total heat absorption contribution of different standard samples is calculated based on the heat absorption and weights.

[0014] In some embodiments, different weights are assigned to the heat absorption of different flame-retardant components, including:

[0015] The flame-retardant components include magnesium hydroxide, aluminum hydroxide, and ethylene-vinyl acetate copolymer;

[0016] The unit heat absorbed and the amount of water produced per gram of magnesium hydroxide and aluminum hydroxide during decomposition were obtained respectively, and the weights of magnesium hydroxide and aluminum hydroxide were calculated based on the unit heat absorbed and the amount of water produced respectively.

[0017] The weights of the ethylene-vinyl acetate copolymer are calculated based on the weights of magnesium hydroxide and aluminum hydroxide.

[0018] In some embodiments, the formula for calculating the sum of the heat absorption contributions of different standard samples based on the heat absorption and weights is as follows:

[0019] FRPI=0.348*H[Al(OH)3]+0.735*H[Mg(OH)2]+0.536*H[EVA]

[0020] Wherein, H[Al(OH)3] represents the heat endurance generated when all aluminum hydroxide in the corresponding standard sample undergoes thermal decomposition, H[Mg(OH)2] represents the heat endurance generated when all magnesium hydroxide in the corresponding standard sample undergoes thermal decomposition, and H[EVA] represents the heat endurance generated when all ethylene-vinyl acetate copolymers in the corresponding standard sample undergo thermal decomposition.

[0021] In some embodiments, obtaining the heat absorption of different flame-retardant components in different standard samples includes:

[0022] Obtain the endothermic-temperature curve of the standard sample;

[0023] Based on the decomposition temperature range of the different flame retardant components, the endothermic peaks of the different flame retardant components are determined on the endothermic-temperature curves respectively.

[0024] The area of ​​the endothermic peaks is calculated to obtain the heat absorption of different flame-retardant components.

[0025] In some embodiments, obtaining the endothermic-temperature curve of the standard sample includes:

[0026] The granular standard sample is pressed into a thin sheet under preset conditions using a flat vulcanizing machine.

[0027] A predetermined mass of the thin film is placed in a crucible, which is then placed in a differential scanning calorimeter (DSC). The DSC is heated to a predetermined temperature at a predetermined heating rate to obtain the endothermic-temperature curve of the standard sample.

[0028] In some embodiments, before placing the crucible into the differential scanning calorimeter, the method further includes:

[0029] Drill a hole in the crucible lid and place the drilled crucible lid on the crucible;

[0030] The differential scanning calorimeter is preheated until the temperature reaches 45℃~55℃.

[0031] In some embodiments, the preset heating rate ranges from 10 to 20 K / min, and the preset temperature ranges from 590°C to 610°C.

[0032] In some embodiments, evaluating the flame retardant performance of the test sample based on the magnitude of the Fire Performance Index (FPI) includes:

[0033] If the fire performance index (FPI) of the test sample is less than 0.15, the flame retardant performance of the test sample is determined to be at level four.

[0034] If the fire performance index (FPI) of the test sample is not less than 0.15 and less than 0.25, then the flame retardant performance of the test sample is determined to be at level three.

[0035] If the fire performance index (FPI) of the test sample is not less than 0.25 and less than 0.5, then the flame retardant performance of the test sample is determined to be at the second level.

[0036] If the fire performance index (FPI) of the test sample is not less than 0.5, then the flame retardant performance of the test sample is determined to be at the first level.

[0037] In some embodiments, the FRPI-FPI linear relationship is FPI = 0.001 * FRPI - 0.027.

[0038] The beneficial effects of the technical solution provided in this application include:

[0039] This application provides a method for testing the fire performance index of low-smoke halogen-free materials. Since a linear relationship between the FRPI and FPI of different standard samples can be obtained, only the FRPI of the sample to be tested needs to be acquired. The FPI of the sample can then be calculated based on the obtained FRPI-FPI linear relationship, thus enabling the evaluation of the flame retardant performance of the sample. Therefore, this method can accurately test the fire performance index of low-smoke halogen-free materials using only a differential scanning calorimeter. While ensuring testing accuracy, it simplifies the testing process, lowers the testing threshold, and enables a more convenient and rapid evaluation of the flame retardant performance of low-smoke halogen-free materials. Furthermore, the entire testing process does not involve open flames, has a high safety factor, and is environmentally friendly. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 Differential scanning calorimeter test curve of the sample to be tested for the method of testing the fire performance index of low smoke halogen-free materials provided in the embodiments of this application;

[0042] Figure 2 The FPI-FRPI relationship diagram for the method of testing the fire performance index of low-smoke halogen-free materials provided in the embodiments of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] This application provides a method for testing the fire performance index of low-smoke halogen-free materials, which solves the problems of high testing cost, cumbersome testing process and high requirements for testing environment when using a cone calorimeter to measure the fire performance index of materials in related technologies.

[0045] See Figure 2 As shown, the steps of this method are as follows: First, obtain the flame retardant performance index (FRPI) of different standard samples. Then, use a cone calorimeter to measure the fire performance index (FPI) of the different standard samples. Fit multiple sets of FRPI and FPI to obtain a linear relationship between FRPI and FPI. Subsequently, obtain the FRPI of the sample to be tested. Calculate the FPI of the sample to be tested based on the FRPI-FPI linear relationship and the FRPI. Evaluate the flame retardant performance of the sample to be tested based on the magnitude of the FPI. After obtaining the FRPI-FPI linear relationship, this method can accurately test the fire performance index of low-smoke halogen-free materials using only a differential scanning calorimeter in subsequent tests. While ensuring testing accuracy, it simplifies the testing process, lowers the testing threshold, and enables a more convenient and rapid evaluation of the flame retardant performance of low-smoke halogen-free materials. Furthermore, the entire testing process does not involve open flames, has a high safety factor, and is environmentally friendly.

[0046] Furthermore, the step of obtaining the Flame Retardant Performance Index (FRPI) of different standard samples mainly includes: firstly, obtaining the heat absorption of different flame retardant components in different standard samples; then, assigning different weights to the heat absorption of different flame retardant components; and finally, calculating the total heat absorption contribution of different standard samples based on the heat absorption and weights. Specifically, the types of flame retardant components in different standard samples are the same, but the proportion of each flame retardant component in different standard samples is different, and the flame retardant ability of different flame retardant components is different. Since the total heat absorption of the standard samples is related to the proportion of each flame retardant component, different weights are assigned to the heat absorption of different flame retardant components in the standard samples.

[0047] Furthermore, the flame-retardant components in the different standard samples generally include three main categories: magnesium hydroxide, aluminum hydroxide, and ethylene-vinyl acetate copolymer. The steps of assigning different weights to the heat absorption of the different flame-retardant components mainly include: firstly, obtaining the unit heat absorption and the amount of water produced per gram of magnesium hydroxide and aluminum hydroxide during decomposition, and calculating the weights of magnesium hydroxide and aluminum hydroxide based on the unit heat absorption and the amount of water produced; and then calculating the weight of ethylene-vinyl acetate copolymer based on the weights of magnesium hydroxide and aluminum hydroxide.

[0048] Specifically, the energy consumed in decomposing 1g of aluminum hydroxide and magnesium hydroxide is H'(Al(OH)3) and H'(Mg(OH)2) respectively. In this process, the amounts of water produced are n1 and n2 respectively, which can be calculated using the following formulas:

[0049] n1=2 / [3*M(AI(OH)3)] Formula (1)

[0050] n2=1 / M(Mg(OH)2) Formula (2)

[0051] Where M(AI(OH)3) is the relative molecular mass of aluminum hydroxide, and M(Mg(OH)2) is the relative molecular mass of magnesium hydroxide.

[0052] Assuming the weight of aluminum hydroxide is X1, the formula for calculating the weight of magnesium hydroxide, X2, is as follows:

[0053] X2 = [H'(Mg(OH)2) / H'(AI(OH)3)+n2 / n1]*X1*0.98 Formula (3)

[0054] In actual combustion, ethylene-vinyl acetate copolymer (EVA) forms a complex with the two flame-retardant components, aluminum hydroxide and magnesium hydroxide, to form a high molecular weight polymer. Therefore, the formula for calculating the weight of ethylene-vinyl acetate copolymer (EVA) by multiplying by 3 is as follows:

[0055] X3 = (X1 + X2) / 2 * 0.98 (Formula 4)

[0056] Furthermore, the formula for calculating the sum of the heat absorption contributions of different standard samples based on the heat absorption and weights is as follows:

[0057] FRPI=0.348*H[Al(OH)3]+0.735*H[Mg(OH)2]+0.531*H[EVA] Formula (5)

[0058] Wherein, H[Al(OH)3] represents the heat endurance generated during the thermal decomposition of all aluminum hydroxides in the corresponding standard sample, H[Mg(OH)2] represents the heat endurance generated during the thermal decomposition of all magnesium hydroxides in the corresponding standard sample, and H[EVA] represents the heat endurance generated during the thermal decomposition of all ethylene-vinyl acetate copolymers in the corresponding standard sample. 0.348 is the weight of aluminum hydroxide, 0.735 is the weight of magnesium hydroxide, and 0.531 is the weight of ethylene-vinyl acetate copolymer.

[0059] Further, see Figure 1 As shown, the steps of obtaining the heat absorption of different flame retardant components in different standard samples mainly include: firstly, obtaining the heat absorption-temperature curve of the standard sample; then, determining the heat absorption peak of different flame retardant components on the heat absorption-temperature curve according to the decomposition temperature range of different flame retardant components; and finally, calculating the area of ​​the heat absorption peak to obtain the heat absorption of different flame retardant components.

[0060] Furthermore, the step of obtaining the endothermic-temperature curve of the standard sample mainly includes: firstly, pressing the granular standard sample into a thin sheet using a flat vulcanizing machine under preset conditions; then, placing a preset mass of the thin sheet in a crucible; placing the crucible in a differential scanning calorimeter (DSC); and heating the DSC to a preset temperature at a preset heating rate to obtain the endothermic-temperature curve of the standard sample. Specifically, since the initial form of the sample is granular, the granular standard sample is pressed into a thin sheet of 2±0.3 mm using a flat vulcanizing machine under preset conditions of 170℃ and 20 MPa. 5–10 mg of the thin sheet is placed in the crucible of the DSC, the crucible is covered, and the temperature is raised to a preset temperature at a preset heating rate to obtain the endothermic-temperature curve of the standard sample; see [link to relevant documentation]. Figure 1 As shown, the heat absorption-temperature curve will show multiple heat absorption peaks, which are the heat absorption peaks during the thermal decomposition of each flame retardant component. According to the different decomposition temperature ranges of each flame retardant component (aluminum hydroxide: 200~350℃, magnesium hydroxide: 350~450℃, EVA: 450~600℃), their respective heat absorption peaks can be identified. Through data processing, the peak area of ​​each heat absorption peak is obtained, which is the heat absorption of each flame retardant component.

[0061] Furthermore, before placing the crucible into the differential scanning calorimeter, a hole is drilled in the crucible lid to balance the air pressure inside and outside the crucible. The drilled crucible lid is then placed on the crucible, and the differential scanning calorimeter is preheated until the temperature reaches 45°C to 55°C. After completing the above steps, the crucible is then placed into the differential scanning calorimeter.

[0062] Furthermore, the preset heating rate ranges from 10 to 20 K / min, and the preset temperature ranges from 590℃ to 610℃.

[0063] Furthermore, the step of evaluating the flame retardant performance of the test sample based on the magnitude of the Fire Performance Index (FPI) mainly includes:

[0064] If the fire performance index (FPI) of the test sample is less than 0.15, the flame retardant performance of the test sample is determined to be at level four, indicating that the flame retardant performance of the test sample is very weak.

[0065] If the fire performance index (FPI) of the test sample is not less than 0.15 and less than 0.25, then the flame retardant performance of the test sample is determined to be at level three, indicating that the flame retardant performance of the test sample is relatively weak.

[0066] If the fire performance index (FPI) of the test sample is not less than 0.25 and less than 0.5, then the flame retardant performance of the test sample is determined to be at the second level, indicating that the flame retardant performance of the test sample is relatively high.

[0067] If the Fire Performance Index (FPI) of the test sample is not less than 0.5, then the flame retardancy of the test sample is determined to be at the first level, indicating that the flame retardancy of the test sample is very high and the flame retardancy is the best.

[0068] Furthermore, the linear relationship between FRPI and FPI is FPI = 0.001 * FRPI - 0.027.

[0069] The above will be explained below through specific embodiments.

[0070] The granular sample to be tested was pressed into 2.1 mm thin sheets using a flat vulcanizing machine under preset conditions of 170℃ and 20 MPa. 8 mg of these thin sheets were placed in the crucible of the differential scanning calorimeter (DSC), the crucible lid was closed, and holes were punched in the lid to obtain the sample crucible. The DSC was programmed to heat from 50℃ to 600℃ at a rate of 10 K / min, with a helium atmosphere flow rate of 40 mL / min. The DSC was turned on and allowed to reach the sample loading temperature of 50℃. The crucible was placed in the sample position, and the DSC was allowed to continue heating at the preset rate of 10 K / min to 600℃. Finally, the sample was obtained. The endothermic-temperature curve of the sample under test was obtained. Multiple endothermic peaks appeared in the curve. Data processing was used to obtain the heat absorption of each flame-retardant component. The heat absorption of Al(OH)3 was 394.1 J / g, Mg(OH)2 was 361.4 J / g, and EVA was 149.7 J / g. Based on the relationship between the heat absorption of each flame-retardant component and FRPI, the FRPI value of the sample under test was calculated to be 482.7 J / g. According to the linear relationship between FRPI and FPI, the FPI value of the sample under test was calculated to be 0.4557 m²·s / kW, indicating that the material possesses a high level of flame-retardant performance.

[0071] Repeating the above steps, the test data for other low-smoke halogen-free flame retardant materials are listed in the table below:

[0072]

[0073] The method for testing the fire performance index of low-smoke halogen-free materials is simple to measure and operate, with a low testing threshold. The fire performance index can be accurately tested using the more commonly used differential scanning calorimeter, which can more conveniently and quickly evaluate the flame retardant performance of materials, providing data support for material research and development and application. Furthermore, the differential scanning calorimeter is easy to operate, has low environmental requirements, and low operating costs. Compared with the cone calorimeter, it does not produce open flames, has a high safety factor, and is environmentally friendly.

[0074] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0075] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0076] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for testing the fire performance index of low-smoke halogen-free materials, characterized in that, The steps include: The flame retardant performance index (FRPI) of different standard samples was obtained. The fire performance index (FPI) of different standard samples was measured using a cone calorimeter. The FRPI and FPI are fitted together to obtain a linear relationship between FRPI and FPI. The flame retardant performance index (FRPI) of the sample to be tested is obtained. The fire performance index (FPI) of the sample to be tested is calculated based on the linear relationship between FRPI and FPI and the flame retardant performance index (FRPI) of the sample to be tested. The flame retardant performance of the sample to be tested is evaluated based on the magnitude of the fire performance index (FPI) of the sample to be tested. The process of obtaining the flame retardant performance index (FRPI) for different standard samples includes: The heat absorption of different flame-retardant components in different standard samples was obtained respectively; Different weights are assigned to the heat absorption of different flame retardant components, and the total heat absorption contribution of different standard samples is calculated based on the heat absorption and weights.

2. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 1, characterized in that, Assigning different weights to the heat absorption of different flame-retardant components includes: The flame-retardant components include magnesium hydroxide, aluminum hydroxide, and ethylene-vinyl acetate copolymer; The unit heat absorbed and the amount of water produced per gram of magnesium hydroxide and aluminum hydroxide during decomposition were obtained respectively, and the weights of magnesium hydroxide and aluminum hydroxide were calculated based on the unit heat absorbed and the amount of water produced respectively. The weights of the ethylene-vinyl acetate copolymer are calculated based on the weights of magnesium hydroxide and aluminum hydroxide.

3. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 1, characterized in that: The formula for calculating the sum of the heat absorption contributions of different standard samples based on the heat absorption and weights is as follows: FRPI=0.348*H[Al(OH)3]+0.735*H[Mg(OH)2]+0.536*H[EVA] Wherein, H[Al(OH)3] represents the heat endurance generated when all aluminum hydroxide in the corresponding standard sample undergoes thermal decomposition, H[Mg(OH)2] represents the heat endurance generated when all magnesium hydroxide in the corresponding standard sample undergoes thermal decomposition, and H[EVA] represents the heat endurance generated when all ethylene-vinyl acetate copolymers in the corresponding standard sample undergo thermal decomposition.

4. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 1, characterized in that, The step of obtaining the heat absorption of different flame-retardant components in different standard samples includes: Obtain the endothermic-temperature curve of the standard sample; Based on the decomposition temperature range of the different flame retardant components, the endothermic peaks of the different flame retardant components are determined on the endothermic-temperature curves respectively. The area of ​​the endothermic peaks is calculated to obtain the heat absorption of different flame-retardant components.

5. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 4, characterized in that, Obtaining the endothermic-temperature curve of the standard sample includes: The granular standard sample is pressed into a thin sheet under preset conditions using a flat vulcanizing machine. A predetermined mass of the thin film is placed in a crucible, which is then placed in a differential scanning calorimeter (DSC). The DSC is heated to a predetermined temperature at a predetermined heating rate to obtain the endothermic-temperature curve of the standard sample.

6. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 5, characterized in that, Before placing the crucible into the differential scanning calorimeter, the procedure further includes: Drill a hole in the crucible lid and place the drilled crucible lid on the crucible; The differential scanning calorimeter is preheated until the temperature reaches 45℃~55℃.

7. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 5, characterized in that: The preset heating rate ranges from 10 to 20 K / min, and the preset temperature ranges from 590℃ to 610℃.

8. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 1, characterized in that, The evaluation of the flame retardant performance of the test sample based on the Fire Performance Index (FPI) includes: If the fire performance index (FPI) of the test sample is less than 0.15, the flame retardant performance of the test sample is determined to be at level four. If the fire performance index (FPI) of the test sample is not less than 0.15 and less than 0.25, then the flame retardant performance of the test sample is determined to be at level three. If the fire performance index (FPI) of the test sample is not less than 0.25 and less than 0.5, then the flame retardant performance of the test sample is determined to be at the second level. If the fire performance index (FPI) of the test sample is not less than 0.5, then the flame retardant performance of the test sample is determined to be at the first level.

9. The method for testing the fire performance index of low-smoke halogen-free materials as described in claim 1, characterized in that: The linear relationship between FRPI and FPI is FPI = 0.001 * FRPI - 0.027.

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