Carbon fiber color difference detection method

Abstract

The invention discloses a carbon fiber color difference detection method which comprises the following steps: when the fiber winding amount of a to-be-detected carbon fiber filament ingot reaches a preset value, respectively carrying out chromaticity detection on a standard sample filament ingot and the to-be-detected carbon fiber filament ingot to obtain color difference data, and judging whether the color difference of the to-be-detected carbon fiber is qualified or not according to the color difference data and a tolerance standard; when the fiber winding amount of the to-be-detected carbon fiber filament ingot does not reach a preset value, respectively performing sample preparation on the standard sample filament ingot and the to-be-detected carbon fiber filament ingot to obtain a standard sample and a fiber sample, and then performing chromaticity detection on the standard sample and the fiber sample to obtain chromatic aberration data; judging whether the color difference of the to-be-detected carbon fiber is qualified or not according to the color difference data and the tolerance standard; wherein the sample preparation mode is winding plate sample preparation or detection box sample preparation; according to the method, direct chromaticity measurement or chromaticity measurement after sample preparation can be carried out, whether the color difference of the carbon fibers to be measured is qualified or not is judged, the carbon fibers with unqualified color difference are removed before a woven fabric or prepreg is prepared, and the generation of waste materials and the operation cost are reduced.

Description

Technical Field

[0001] The invention relates to a carbon fiber color difference detection method and belongs to the technical field of carbon fiber color difference detection. Background Art

[0002] Polyacrylonitrile-based carbon fiber has excellent properties such as high specific strength, wear resistance, aging resistance, corrosion resistance, thermal conductivity, and electrical conductivity. Carbon fiber multifilament can be used to prepare carbon fiber woven fabrics, prepregs, and composite materials, and can be widely used in national defense, military industry, new energy vehicles and other civilian industrial fields. The huge market demand has promoted the development of the industry and brought about fierce competition.

[0003] There are direct and reliable data to determine whether carbon fiber tensile properties, sizing agent content, density and other items are qualified, but there is no direct and reliable method to determine whether color difference is qualified. Visual evaluation itself is affected by various conditions. Due to fiber color defects, the prepared woven fabrics or prepregs will have color difference defects, and the prepared carbon fiber products will have unqualified appearance, which will cause customers to stop production, generate waste materials, and increase operating costs. Therefore, before carbon fiber is prepared into intermediate products or composite finished products, it is of great significance to quantitatively evaluate the color difference of carbon fiber multifilaments. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for detecting color difference of carbon fiber. The method can distinguish the fiber winding amount of the carbon fiber ingot to be tested, and can perform direct colorimetric measurement or colorimetric measurement after sample preparation to determine whether the color difference of the carbon fiber to be tested is qualified, thereby eliminating carbon fiber with unqualified color difference before preparing woven fabrics or prepregs, reducing the generation of waste and operating costs.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions: The present invention provides a method for detecting color difference of carbon fiber, comprising: When the fiber winding amount of the carbon fiber spindle to be tested reaches a preset value, the colorimetric detection is performed on the standard sample spindle and the carbon fiber spindle to be tested to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard; When the fiber winding amount of the carbon fiber spindle to be tested does not reach a preset value, the standard sample spindle and the carbon fiber spindle to be tested are first sampled to obtain a standard sample and a fiber sample respectively, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and whether the color difference of the carbon fiber to be tested is qualified is judged according to the color difference data and the tolerance standard; wherein the sample preparation method is winding plate sample preparation or detection box sample preparation.

[0006] Optionally, when the fiber winding amount of the carbon fiber spindle to be tested reaches a preset value, colorimetric detection is performed on the standard sample spindle and the carbon fiber spindle to be tested to obtain color difference data, and whether the color difference of the carbon fiber to be tested is qualified is judged according to the color difference data and the tolerance standard, including: Unwind and remove the damaged fiber bundles on the surface of the standard sample ingot and the carbon fiber ingot to be tested; Place the measuring port of the colorimeter close to the standard sample spindle after the damaged fiber is removed, measure the chromaticity parameters of the standard sample fiber, and record the measurement results; Place the measuring port of the colorimeter close to the carbon fiber ingot to be tested after the damaged fibers have been removed, measure the chromaticity parameters of the carbon fiber to be tested, and record the measurement results; The chromaticity parameters of the standard sample fiber and the chromaticity parameters of the carbon fiber to be tested are compared to obtain the color difference data between the standard sample fiber and the carbon fiber to be tested; Whether the color difference of the carbon fiber to be tested is qualified is determined based on whether the color difference data is within the tolerance standard.

[0007] Optionally, when the fiber winding amount of the carbon fiber ingot to be tested does not reach a preset value, the standard sample ingot and the carbon fiber ingot to be tested are first sampled to obtain a standard sample and a fiber sample, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard, wherein a winding plate is selected for sample preparation, and the carbon fiber color difference detection method includes: Unwind and remove the damaged fiber bundles on the surface of the standard sample ingot and the carbon fiber ingot to be tested; Take a section of fiber bundle from the standard sample spindle after removing the damaged fiber, and evenly wind it in layers on a winding plate to obtain a standard sample; A section of fiber tow is taken from the carbon fiber spindle to be tested after the damaged fibers are removed, and is evenly layered and wound on the second winding plate to obtain a fiber sample; Place the measuring port of the colorimeter close to the standard sample, measure the chromaticity parameters of the standard sample, and record the measurement results; Place the measuring port of the colorimeter close to the fiber sample, measure the chromaticity parameters of the fiber sample, and record the measurement results; Compare the chromaticity parameters of the standard sample and the fiber sample to obtain the color difference data between the standard sample and the fiber sample; Whether the color difference of the carbon fiber to be tested is qualified is determined based on whether the color difference data is within the tolerance standard.

[0008] Optionally, during the sample preparation of the winding plate, the number of winding layers is three, and when the layers are evenly wound, they are distinguished by marking stickers with obvious color difference from the fiber bundles, so that there is no overlap, gap or reversal of fibers in the same layer.

[0009] Optionally, when the fiber winding amount of the carbon fiber spindle to be tested does not reach a preset value, the standard sample spindle and the carbon fiber spindle to be tested are first sampled to obtain a standard sample and a fiber sample, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard, wherein a detection box is selected for sample preparation, and the carbon fiber color difference detection method includes: Unwind and remove the damaged fiber bundles on the surface of the standard sample ingot and the carbon fiber ingot to be tested; Take a section of fiber bundle from the standard sample ingot after the damaged fiber is removed, put the section of fiber bundle into a detection box installed with transparent quartz glass, ensure that the transparent quartz glass is covered by the fiber bundle, and tighten the detection box so that the fiber bundle is flattened to obtain a standard sample; Take a section of fiber tow from the carbon fiber ingot to be tested after the damaged fibers are removed, put the section of fiber tow into the second detection box equipped with transparent quartz glass, ensure that the transparent quartz glass is covered by the fiber tow, and tighten the detection box so that the fiber tow group is flattened to obtain a fiber sample; Place the measuring port of the colorimeter close to the standard sample, that is, place the measuring port of the colorimeter close to the transparent quartz glass surface of the detection box 1, measure the chromaticity parameters of the standard sample through the transparent quartz glass, and record the measurement results; Place the measuring port of the colorimeter close to the fiber sample, that is, place the measuring port of the colorimeter close to the transparent quartz glass surface of the detection box 2, measure the chromaticity parameters of the fiber sample through the transparent quartz glass, and record the measurement results; Compare the chromaticity parameters of the standard sample and the fiber sample to obtain the color difference data between the standard sample and the fiber sample; Whether the color difference of the carbon fiber to be tested is qualified is determined based on whether the color difference data is within the tolerance standard.

[0010] Optionally, the chromaticity parameters include brightness L, red-green chromaticity a and yellow-cyan chromaticity b; the color difference data include dL, da, db, dE* ab .

[0011] Optionally, the standard sample spindle is a Japanese Toray carbon fiber spindle.

[0012] Optionally, the tolerance standards include: dL=2.00, da=2.00, db=2.00 and dE* ab =2.00.

[0013] Optionally, the detection equipment used in the detection method includes a colorimeter, a winding plate, scissors, and a detection box; wherein the detection box includes a spirally detachable upper cover and a lower cover, and a transparent quartz glass is embedded in the middle of the lower cover; the upper cover and the lower cover are both black to prevent light leakage from affecting the color difference measurement results.

[0014] Optionally, the size of the transparent quartz glass matches the measuring port of the colorimeter.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The carbon fiber color difference detection method proposed in the present invention uses the fiber winding amount of the carbon fiber ingot to be tested as a distinction, and can perform direct colorimetric measurement or colorimetric measurement after sample preparation to determine whether the color difference of the carbon fiber to be tested is qualified, thereby eliminating carbon fibers with unqualified color difference before preparing woven fabrics or prepregs, reducing the generation of waste and operating costs; it is helpful to quantitatively characterize the color difference of carbon fibers, and provide basic data for the use of downstream carbon fiber woven fabrics, prepregs, and composites, and is suitable for application and promotion.

[0016] The carbon fiber color difference detection method proposed in the present invention uses a marker sticker with obvious color difference from the fiber bundle to perform layered and uniform winding during the winding plate sample preparation process, so as to achieve no overlapping and no gaps in the same layer of fibers, making the color detection result more accurate.

[0017] The carbon fiber color difference detection method proposed by the present invention can effectively avoid the influence of the light source on the chromaticity detection in the color difference detection method of the detection box sample preparation, and the chromaticity detection result is more accurate.

[0018] The carbon fiber color difference detection method proposed in the present invention avoids disputes over color quality, speeds up color difference determination, reduces management costs, and brings good economic and social benefits to the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor, among which: Figure 1 The flowchart of the carbon fiber color difference detection method in the embodiment of the present invention is shown; Figure 2 A schematic diagram showing the upper cover and the lower cover of the detection box after being disassembled in an embodiment of the present invention; Figure 3 In the embodiment of the present invention shown Figure 2 Bottom view of the lower cover; In the figure: 1. upper cover; 2. lower cover; 2-2 transparent quartz glass. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0021] The application principle of the present invention is described in detail below in conjunction with the accompanying drawings. Example

[0022] like Figure 1 As shown, an embodiment of the present invention provides a carbon fiber color difference detection method, comprising the following steps: S01: When the fiber winding amount of the carbon fiber spindle to be tested reaches a preset value, the colorimetric detection is performed on the standard sample spindle and the carbon fiber spindle to be tested to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard; S02: When the fiber winding amount of the carbon fiber spindle to be tested does not reach a preset value, the standard sample spindle and the carbon fiber spindle to be tested are first sampled to obtain a standard sample and a fiber sample respectively, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and whether the color difference of the carbon fiber to be tested is qualified is judged according to the color difference data and the tolerance standard; wherein the sample preparation method is winding plate sample preparation or detection box sample preparation.

[0023] Specifically, the size of the carbon fiber ingot to be tested (the amount of fiber winding), that is, the amount of carbon fiber wound on the shaft, will affect the curvature of the entire ingot; when the amount of wound carbon fiber is small, the curvature of the ingot is large, and the detection port of the colorimeter is directly attached to the ingot with a large curvature, which will cause a risk of light leakage, thereby directly affecting the accuracy of colorimetric detection. At this time, the colorimetric detection can be carried out by preparing the sample first and then testing; wherein, the preset value is set according to the curvature of the shaft, when the curvature of the shaft is large, the preset value is appropriately increased; when the curvature of the shaft is small, the preset value is appropriately reduced.

[0024] Specifically, the diameter of the carbon fiber ingot shaft barrel to be tested in the present invention is 7-8 cm, and the preset value of the fiber winding amount is 300 m; The carbon fiber color difference detection method proposed in the present invention uses the fiber winding amount of the carbon fiber ingot to be tested as a distinction, and can perform direct colorimetric measurement or colorimetric measurement after sample preparation to determine whether the color difference of the carbon fiber to be tested is qualified, thereby eliminating carbon fibers with unqualified color difference before preparing woven fabrics or prepregs, reducing the generation of waste and operating costs; it is helpful to quantitatively characterize the color difference of carbon fibers, and provide basic data for the use of downstream carbon fiber woven fabrics, prepregs, and composites, and is suitable for application and promotion.

[0025] In this embodiment, when the fiber winding amount of the carbon fiber ingot to be tested reaches a preset value in step S01, the standard sample ingot and the carbon fiber ingot to be tested are respectively subjected to colorimetric detection to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard, which specifically includes the following: Removing damaged fibers: The surfaces of the standard sample spindle and the carbon fiber spindle to be tested may be worn or contaminated. To ensure the accuracy of colorimetric detection, the damaged fiber tows on the surfaces of the standard sample spindle and the carbon fiber spindle to be tested need to be unwound and removed to expose the inner layer as much as possible. The unwinding meters are related to the fiber tow specifications. Small tow carbon fiber has more unwinding meters, while large tow carbon fiber has less unwinding meters. Direct detection of the color of the carbon fiber to be tested: place the measuring port of the colorimeter close to the standard sample spindle after the damaged fiber is removed, measure the color parameters of the standard sample fiber (brightness L, red-green color a and yellow-cyan color b), and record the measurement results; specifically, the colorimeter should be perpendicular to the standard sample spindle to avoid light leakage; specifically, the colorimeter is measured 8 times, and the measurement positions are different positions of the standard sample spindle; Direct detection of the colorimetric properties of standard sample fibers: place the measuring port of the colorimeter close to the carbon fiber ingot to be tested after the damaged fibers have been removed, measure the colorimetric parameters (brightness L, red-green color a, and yellow-cyan color b) of the carbon fiber to be tested, and record the measurement results; specifically, the colorimeter should be perpendicular to the carbon fiber ingot to be tested to avoid light leakage; specifically, the colorimeter is measured 8 times, and the measurement positions are different positions of the carbon fiber ingot to be tested; Parameter comparison: Compare the chromaticity parameters of the standard sample fiber with the chromaticity parameters of the carbon fiber to be tested to obtain the color difference data dL, da, db, dE between the standard sample fiber and the carbon fiber to be tested * ab ; Specifically, the formula for color difference data is as follows:

[0026]

[0027]

[0028]

[0029] in, , , They are the average values ​​of brightness, red-green color, and yellow-cyan color after the colorimeter measures the standard sample silk ingot multiple times; , , They are the average values ​​of brightness, red-green color, and yellow-cyan color after the colorimeter measures the carbon fiber ingot for multiple times; dE * ab Indicates the total color difference.

[0030] Qualified judgment: judge whether the color difference of the carbon fiber to be tested is qualified according to whether the color difference data is within the tolerance standard; Specifically, in this embodiment, the tolerance standards are set as: dL=2.00, da=2.00, db=2.00 and dE* ab =2.00; When the color difference data dL, da, db, dE * ab All are within the tolerance standard, and the color difference of the tested carbon fiber is qualified; When the color difference data dL, da, db, dE * ab If the color difference of the tested carbon fiber is not within the tolerance standard, it will fail to meet the requirements.

[0031] In this embodiment, the colorimeter is calibrated in advance according to the blackboard and whiteboard. After the calibration is passed, the display parameters CIE Lab, the measurement mode SCI, and the color difference formula dE* are set. ab , angle 10°, light source D65, and the average number of tests is 8 times.

[0032] In this embodiment, the standard sample spindle is a Japanese Toray carbon fiber spindle.

[0033] In this embodiment, in step S02, when the fiber winding amount of the carbon fiber spindle to be tested does not reach the preset value, the standard sample spindle and the carbon fiber spindle to be tested are firstly sampled to obtain a standard sample and a fiber sample, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and whether the color difference of the carbon fiber to be tested is qualified is judged according to the color difference data and the tolerance standard; Wherein, the sample preparation method is winding plate sample preparation or detection box sample preparation; When a wound plate is used for sample preparation, step S02 specifically includes: Remove damaged fibers. The surfaces of the standard sample spindle and the carbon fiber spindle to be tested may be worn or contaminated. To ensure the accuracy of colorimetric detection, the damaged fiber bundles on the surfaces of the standard sample spindle and the carbon fiber spindle to be tested need to be unwound and removed before winding the plate sample. Wrapping board sample preparation 1: Use scissors to cut a section of fiber bundle on the standard sample spindle after removing the damaged fibers, and evenly wind it in layers on the winding board 1 to obtain a standard sample; Wrapping plate sample preparation 2: Use scissors to cut a section of fiber tow from the carbon fiber ingot to be tested after removing the damaged fibers, and evenly wind it in layers on the wrapping plate 2 to obtain a fiber sample; Specifically, during the sample preparation of the wound board, three layers are wound, and when the layers are evenly wound, they are distinguished by marking stickers with obvious color difference from the fiber bundles, so that there is no overlap, gap or reversal of fibers in the same layer.

[0034] Specifically, in the process of preparing the winding board sample, a wooden winding board (winding board 1 and winding board 2) with a length of 280 mm, a width of 100 mm and a thickness of about 10 mm was selected, and the outside of the winding board was wrapped with release paper; one end of the carbon fiber was fixed on the winding board wrapped with release paper, and three layers were wound evenly, without overlapping or turning; when winding the second layer, on the basis of winding the first layer, a 20 mm long white mark sticker was pasted on both ends of the winding board to ensure that there was no overlapping when winding the second layer; when winding the third layer, on the basis of winding the second layer, a 20 mm long white mark sticker was pasted on both ends of the winding board to ensure that there was no overlapping when winding the third layer; Chromaticity test of standard sample: place the measuring port of the colorimeter close to the standard sample (wound wrapping board 1), measure the chromaticity parameters (brightness L, red-green color a and yellow-cyan color b) of the standard sample, and record the measurement results; specifically, the colorimeter should be perpendicular to the standard sample to avoid light leakage; specifically, the colorimeter is measured 8 times, and the measurement positions are different positions of the standard sample (wound wrapping board 1); Fiber sample colorimetric detection: place the measuring port of the colorimeter close to the fiber sample (wound wrapping board 2), measure the colorimetric parameters of the fiber sample (brightness L, red-green color a, and yellow-cyan color b), and record the measurement results; specifically, the colorimeter should be perpendicular to the fiber sample to avoid light leakage; specifically, the colorimeter is measured 8 times, and the measurement positions are different positions of the fiber sample (wound wrapping board 2); Specifically, this measurement method is the same as the direct measurement above. The colorimeter needs to be calibrated. After calibration, set the display parameters CIE Lab, measurement mode SCI, and color difference formula dE* ab , angle 10°, light source D65, and the average number of tests is 8 times.

[0035] Parameter comparison: Compare the chromaticity parameters of the standard sample and the fiber sample to obtain the color difference data dL, da, db, dE between the standard sample and the fiber sample * ab ; In this step, the calculation method of the color difference data is the same as that in the direct measurement, and the average value of 8 data is taken to calculate the difference; Qualified judgment: judge whether the color difference of the carbon fiber to be tested is qualified according to whether the color difference data is within the tolerance standard.

[0036] When the color difference data dL, da, db, dE * ab All are within the tolerance standard, and the color difference of the tested carbon fiber is qualified; When the color difference data dL, da, db, dE * ab If the color difference of the tested carbon fiber is not within the tolerance standard, it will fail to meet the requirements.

[0037] When the test kit is used for sample preparation, step S02 specifically includes: Remove damaged fibers. The surfaces of the standard sample spindle and the carbon fiber spindle to be tested may be worn or contaminated. To ensure the accuracy of colorimetric detection, the damaged fiber bundles on the surfaces of the standard sample spindle and the carbon fiber spindle to be tested need to be unwound and removed before winding the plate sample. Test box sample preparation 1: Use scissors to cut a section of fiber bundle from the standard sample ingot after removing the damaged fiber, and put the section of fiber bundle into the test box 1 installed with transparent quartz glass, ensuring that the transparent quartz glass is covered by the fiber bundle, and tighten the test box to make the fiber bundle group flat, so as to obtain the standard sample; Test box sample preparation 2: Use scissors to cut a section of fiber bundle from the carbon fiber ingot to be tested after removing the damaged fibers, and put the section of fiber bundle into the test box 2 installed with transparent quartz glass, ensuring that the transparent quartz glass is covered by the fiber bundle, and tighten the test box to make the fiber bundle group flat, so as to obtain a fiber sample; Specifically, the detection kit is as follows Figure 2-Figure 3 As shown, the detection box includes a screw-detachable upper cover 1 and a lower cover 2, and a transparent quartz glass 2-2 is embedded in the middle of the lower cover 2; the upper cover 1 includes a connected clamping part and a connecting part, and a thread is provided on the inner side of the connecting part. The spiral mouth of the lower cover 2 matches the thread on the inner side of the connecting part for screw tightening; the clamping part matches the size of the spiral mouth, and when the upper cover 1 and the lower cover 2 of the detection box are tightened and closed through the connecting part and the spiral mouth, the clamping part sinks into the spiral mouth and cooperates with the lower cover 2 to achieve the clamping function; the upper cover 1 and the lower cover 2 are both black to avoid light leakage affecting the color difference measurement results; the detection box is cylindrical, and the transparent quartz glass 2-2 in the middle is also circular with a thickness of about 3 mm; the size of the transparent quartz glass matches the measuring port of the colorimeter to avoid the risk of light leakage.

[0038] Chromaticity test of standard sample: place the measuring port of the colorimeter close to the standard sample, that is, place the measuring port of the colorimeter close to the transparent quartz glass surface of the test box 1, measure the chromaticity parameters (brightness L, red-green color a and yellow-cyan color b) of the standard sample through the transparent quartz glass, and record the measurement results; Fiber sample chromaticity detection: Place the measuring port of the colorimeter close to the fiber sample, that is, place the measuring port of the colorimeter close to the transparent quartz glass surface of the detection box 2, measure the chromaticity parameters (brightness L, red-green color a and yellow-cyan color b) of the fiber sample through the transparent quartz glass, and record the measurement results; Specifically, before measuring, wipe the surface of the quartz glass with a soft cotton cloth dipped in alcohol or blow it with an air gun to keep the quartz glass clean and not affect the measurement results; the colorimeter needs to be calibrated. After the calibration is passed, set the display parameters CIELab, the measurement mode SCI, and the color difference formula dE* ab, angle 10°, light source D65; the number of measurements is set to 3; Parameter comparison: Compare the chromaticity parameters of the standard sample and the fiber sample to obtain the color difference data dL, da, db, dE between the standard sample and the fiber sample * ab ; dL, da, db are all differences calculated by taking the average of 3 data.

[0039] Qualified judgment: judge whether the color difference of the carbon fiber to be tested is qualified according to whether the color difference data is within the tolerance standard.

[0040] When the color difference data dL, da, db, dE * ab All are within the tolerance standard, and the color difference of the tested carbon fiber is qualified; When the color difference data dL, da, db, dE * ab If the color difference of the tested carbon fiber is not within the tolerance standard, it will fail to meet the requirements.

[0041] In summary, using a detection box to test the chromaticity and color difference of the fiber can avoid the light leakage problem caused by the curvature of the shaft and the low detection timeliness of winding sample preparation, improve accuracy and repeatability, and do not require a complicated sample preparation process. It is easy to operate and has strong scalability. Example

[0042] Using the carbon fiber color difference detection method described in Example 1, according to the three color difference detection methods mentioned in the present invention (carbon fiber ingot direct detection, winding plate sample detection and detection box sample detection), a fiber ingot with a carbon fiber number of T7-191 (bore diameter 7 cm, fiber winding amount 300m) was used to perform three detection tests respectively, and the data are shown in the following table:

[0043] According to the statistics in the table, the Cv value of direct detection of carbon fiber ingot is 16.25%, the Cv value of winding plate sample test is 15.52%; and the Cv value of test box sample test is 15.08%.

[0044] The statistical results show that the three color difference detection methods can accurately detect whether the carbon fiber to be tested is qualified; at the same time, the fluctuation of direct detection of carbon fiber spindle is larger than that of the other two sample preparation tests (wrap plate sample preparation test and test box sample preparation test), and there may be the possibility of light leakage during the test; however, the test box sample preparation test is more stable than the wrap plate sample preparation test, so the test box sample preparation test result is more stable; In summary, when the curvature of the fiber spindle is relatively large, that is, when the fiber winding amount is small / does not reach the preset value, sample preparation and testing are adopted, among which sample preparation and testing with a detection box is preferred.

[0045] Among them, the Cv value is the coefficient of variation, which is a normalized measure of the degree of dispersion of the probability distribution and is defined as the ratio of the standard deviation to the mean; The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A method for detecting color difference of carbon fiber, characterized in that: include: When the fiber winding amount of the carbon fiber spindle to be tested reaches a preset value, the colorimetric detection is performed on the standard sample spindle and the carbon fiber spindle to be tested to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard; When the fiber winding amount of the carbon fiber spindle to be tested does not reach a preset value, the standard sample spindle and the carbon fiber spindle to be tested are first sampled to obtain a standard sample and a fiber sample respectively, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and whether the color difference of the carbon fiber to be tested is qualified is judged according to the color difference data and the tolerance standard; wherein the sample preparation method is winding plate sample preparation or detection box sample preparation.

2. The carbon fiber color difference detection method according to claim 1, characterized in that: When the fiber winding amount of the carbon fiber spindle to be tested reaches a preset value, the colorimetric detection is performed on the standard sample spindle and the carbon fiber spindle to be tested to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard, including: Unwind and remove the damaged fiber bundles on the surface of the standard sample ingot and the carbon fiber ingot to be tested; Place the measuring port of the colorimeter close to the standard sample spindle after the damaged fiber is removed, measure the chromaticity parameters of the standard sample fiber, and record the measurement results; Place the measuring port of the colorimeter close to the carbon fiber ingot to be tested after the damaged fibers have been removed, measure the chromaticity parameters of the carbon fiber to be tested, and record the measurement results; The chromaticity parameters of the standard sample fiber and the chromaticity parameters of the carbon fiber to be tested are compared to obtain the color difference data between the standard sample fiber and the carbon fiber to be tested; Whether the color difference of the carbon fiber to be tested is qualified is determined based on whether the color difference data is within the tolerance standard.

3. The carbon fiber color difference detection method according to claim 2, characterized in that: When the fiber winding amount of the carbon fiber ingot to be tested does not reach the preset value, the standard sample ingot and the carbon fiber ingot to be tested are first sampled to obtain a standard sample and a fiber sample, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard, wherein a winding plate is selected for sample preparation, and the carbon fiber color difference detection method includes: Unwind and remove the damaged fiber bundles on the surface of the standard sample ingot and the carbon fiber ingot to be tested; Take a section of fiber bundle from the standard sample spindle after removing the damaged fiber, and evenly wind it in layers on a winding plate to obtain a standard sample; A section of fiber tow is taken from the carbon fiber spindle to be tested after the damaged fibers are removed, and is evenly layered and wound on the second winding plate to obtain a fiber sample; Place the measuring port of the colorimeter close to the standard sample, measure the chromaticity parameters of the standard sample, and record the measurement results; Place the measuring port of the colorimeter close to the fiber sample, measure the chromaticity parameters of the fiber sample, and record the measurement results; Compare the chromaticity parameters of the standard sample and the fiber sample to obtain the color difference data between the standard sample and the fiber sample; Whether the color difference of the carbon fiber to be tested is qualified is determined based on whether the color difference data is within the tolerance standard.

4. The carbon fiber color difference detection method according to claim 3, characterized in that: During the sample preparation of the winding plate, the number of winding layers is three, and when the layers are evenly wound, they are distinguished by marking stickers with obvious color difference from the fiber bundles, so that there is no overlap, gap or reversal of fibers in the same layer.

5. The carbon fiber color difference detection method according to claim 4, characterized in that: When the fiber winding amount of the carbon fiber spindle to be tested does not reach the preset value, the standard sample spindle and the carbon fiber spindle to be tested are first sampled to obtain a standard sample and a fiber sample, and then the standard sample and the fiber sample are subjected to colorimetric detection to obtain color difference data, and the color difference of the carbon fiber to be tested is judged to be qualified according to the color difference data and the tolerance standard, wherein the detection box is selected for sample preparation, and the carbon fiber color difference detection method includes: Unwind and remove the damaged fiber bundles on the surface of the standard sample ingot and the carbon fiber ingot to be tested; Take a section of fiber bundle from the standard sample ingot after the damaged fiber is removed, put the section of fiber bundle into a detection box installed with transparent quartz glass, ensure that the transparent quartz glass is covered by the fiber bundle, and tighten the detection box so that the fiber bundle is flattened to obtain a standard sample; Take a section of fiber tow from the carbon fiber ingot to be tested after the damaged fibers are removed, put the section of fiber tow into the second detection box equipped with transparent quartz glass, ensure that the transparent quartz glass is covered by the fiber tow, and tighten the detection box so that the fiber tow group is flattened to obtain a fiber sample; Place the measuring port of the colorimeter close to the standard sample, that is, place the measuring port of the colorimeter close to the transparent quartz glass surface of the detection box 1, measure the chromaticity parameters of the standard sample through the transparent quartz glass, and record the measurement results; Place the measuring port of the colorimeter close to the fiber sample, that is, place the measuring port of the colorimeter close to the transparent quartz glass surface of the detection box 2, measure the chromaticity parameters of the fiber sample through the transparent quartz glass, and record the measurement results; Compare the chromaticity parameters of the standard sample and the fiber sample to obtain the color difference data between the standard sample and the fiber sample; Whether the color difference of the carbon fiber to be tested is qualified is determined based on whether the color difference data is within the tolerance standard.

6. The carbon fiber color difference detection method according to claim 5, characterized in that: The chromaticity parameters include brightness L, red-green chromaticity a and yellow-cyan chromaticity b; the color difference data includes dL, da, db, dE * ab .

7. The carbon fiber color difference detection method according to claim 1, characterized in that: The standard sample spindle is a Japanese Toray carbon fiber spindle.

8. The carbon fiber color difference detection method according to claim 1, characterized in that: The tolerance standards include: dL=2.00, da=2.00, db=2.00 and dE * ab =2.

00.

9. The carbon fiber color difference detection method according to claim 6, characterized in that: The detection equipment used in the detection method includes a colorimeter, a winding plate, scissors, and a detection box; wherein the detection box includes a spirally detachable upper cover and a lower cover, and a transparent quartz glass is embedded in the middle of the lower cover; the upper cover and the lower cover are both black to prevent light leakage from affecting the color difference measurement result.

10. The carbon fiber color difference detection method according to claim 9, characterized in that: The size of the transparent quartz glass matches the measuring port of the colorimeter.

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