Method for detecting hue of colorant
By simulating the color development effect of pigments in PVC production, and using open mill mixing and colorimeter detection, the problem of poor accuracy of visual detection was solved, enabling accurate identification and stability testing of pigment hues, and reducing production costs and resource waste.
Patent Information
- Application Number
- CN202511962291.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-24
- Publication Date
- 2026-03-20
AI Technical Summary
In the existing technology, the hue detection of PVC pigments relies on visual observation, which results in poor accuracy and low repeatability of the test results. It is difficult to accurately identify hue differences, which leads to unqualified pigments entering the production process, resulting in increased production costs, longer production cycles, and product scrap.
PVC resin and pigments are mixed using an open mill to prepare standard and test pieces. Visual comparison and colorimeter testing are used, combined with the judgment standard of △E≤0.8, to simulate the color development effect of pigments in actual production process, ensuring the accuracy and consistency of test results.
It enables accurate and rapid detection of pigment hue, reduces formula adjustments and product scrap during production, and improves the color stability of PVC products and the market competitiveness of enterprises.
Smart Images
Figure CN121702828A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of PVC film raw material testing technology, and more specifically to a method for detecting the hue of colorants. Background Technology
[0002] In the PVC plastics manufacturing industry, colorants are the core raw materials that determine the color of products, and their hue stability directly affects the quality consistency and market acceptance of end products. To ensure production continuity and product qualification rate, colorants must undergo hue conformity testing upon arrival at the factory to ensure they are consistent with the standard colorants required for production.
[0003] However, current technologies for hue detection of PVC pigments primarily rely on direct visual observation of the pigment's appearance. This is because the visible color of the pigment cannot accurately reflect its color development during actual production. This is because PVC production involves high-temperature processing steps such as mixing and calendering. During these processes, pigments undergo color changes due to factors like temperature and shear force. Some pigments that appear visually identical may exhibit significant hue deviations after processing. Furthermore, visual observation is heavily influenced by the subjective judgment of the inspector and ambient lighting conditions, resulting in poor accuracy and repeatability, making it difficult to accurately identify hue differences in pigments.
[0004] The shortcomings of the aforementioned testing methods can easily lead to substandard pigments entering the production process, resulting in color deviations in PVC products produced under the same formula and process conditions. To correct the color, companies need to invest additional costs to adjust process parameters or formulas, which not only increases production costs and extends the production cycle, but may also lead to the scrapping of batches of products due to color deviations exceeding the allowable range, further exacerbating resource waste. Furthermore, insufficient product color stability can reduce customer satisfaction and weaken the company's market competitiveness.
[0005] Therefore, developing a colorimetric detection technology that balances practicality, accuracy, and standardization has become a key requirement for addressing the pain points in colorimetric quality control in the PVC industry. Summary of the Invention
[0006] The purpose of this invention is to provide a method for detecting the hue of pigments, which can accurately and quickly detect the hue of pigments and ensure the stability of the hue of pigments.
[0007] According to the purpose of this invention, a method for detecting the hue of a pigment is provided, comprising the following steps:
[0008] The PVC resin mixture powder and standard colorant, and the PVC resin mixture powder and the colorant to be tested were mixed evenly using an open mill. Then, the mixtures were drawn into pieces to obtain the corresponding standard dark color test pieces and the dark color test pieces.
[0009] The PVC resin mixture powder, standard colorant, and opaque colorant are mixed evenly using an open mill, as are the PVC resin mixture powder, the colorant to be tested, and the opaque colorant. Then, the mixtures are drawn to obtain corresponding standard light-colored test pieces and light-colored test pieces. The opaque colorant includes purple or white colorant.
[0010] Place the standard dark color test piece and the dark color test piece to be tested side by side, and place the standard light color test piece and the light color test piece to be tested side by side to form a colorimetric card;
[0011] Visual observation was used to compare the colors of the standard dark color test piece and the dark color test piece to be tested, as well as the colors of the standard light color test piece and the light color test piece to be tested, on the colorimetric chart.
[0012] A colorimeter was used to test the standard dark color test piece, the dark color test piece to be tested, the standard light color test piece, and the light color test piece to be tested, respectively, to obtain the color difference parameter △E1 of the dark color test piece to be tested relative to the standard dark color test piece, and the color difference parameter △E2 of the light color test piece to be tested relative to the standard light color test piece.
[0013] If the visual observation results show that the corresponding test pieces are similar in color, and both △E1≤0.8 and △E2≤0.8 are satisfied, then the colorant to be tested is deemed qualified.
[0014] As an optional implementation, the selection rule for the opaque pigment is as follows:
[0015] When the standard pigment and the pigment to be tested are both white, the opaque pigment is a purple pigment;
[0016] When the standard pigment and the pigment to be tested are both black, the opaque pigment is white.
[0017] When the standard pigment and the pigment to be tested are colors other than white and black, the opaque pigment is a white pigment.
[0018] As an optional implementation, when the standard pigment and the pigment to be tested are both white, the amount of the standard pigment added is 4% to 5% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 4% to 5% of the mass of the PVC resin mixed powder.
[0019] As an optional implementation, when the color of the standard pigment and the pigment to be tested is black, the amount of the standard pigment added is 0.5% to 1% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 0.5% to 1% of the mass of the PVC resin mixed powder.
[0020] As an optional implementation, when the standard pigment and the pigment to be tested are colors other than white and black, the amount of the standard pigment added is 1% to 2% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 1% to 2% of the mass of the PVC resin mixed powder.
[0021] As an optional implementation, the amount of white pigment added is 4% to 5% of the mass of the PVC resin mixture powder.
[0022] As an optional implementation, the amount of purple pigment added is 0.3% to 0.5% of the mass of the PVC resin mixture powder.
[0023] As an optional implementation, the colorimetric chart includes the following manufacturing process:
[0024] Cut samples of the same size from the standard dark-colored test piece, the dark-colored test piece to be tested, the standard light-colored test piece, and the light-colored test piece to be tested. The cut samples of the same size should be consistent for each test piece. It is also necessary to ensure that the sampling position of all samples is the same, the sampling direction is consistent, and the front and back of the samples are facing the same.
[0025] The standard dark-colored test piece and the test dark-colored test piece are fixed side by side, and the standard light-colored test piece and the test light-colored test piece are fixed side by side, ensuring that the front and back sides of each corresponding test piece are aligned and the warp and weft directions are aligned, to obtain a colorimetric card.
[0026] As an optional embodiment, the components of the PVC resin mixture powder include, by weight: 100 parts of p-1000 type PVC resin, 3 parts of DINP plasticizer, 3 parts of soybean oil, 40 parts of DOP plasticizer, and 2 parts of 139 stabilizer.
[0027] As an optional implementation, the wheel temperature of the open mill is 170℃±2℃, the mixing time is 3min±5s, and the thickness of each prepared test piece is 0.25mm.
[0028] As can be seen from the above technical solutions of the present invention, the color detection method for pigments proposed in the present invention, by simulating the mixing and calendering process of actual production, truly restores the color development effect of pigments in production, and effectively solves the problem of consistent appearance but color deviation after processing that cannot be solved by traditional appearance observation or simple detection.
[0029] By combining visual comparison with digital quantification (△E≤0.8) using a colorimeter, subjective errors are avoided, and the consistency and accuracy of the test results are guaranteed. The operation process is simple, and the equipment involved are all standard industry instruments, making it easy to implement and promote.
[0030] In addition, this method can screen out substandard colorants in advance, reduce cost losses such as formula adjustments and product scrapping in subsequent production, significantly reduce resource waste, and at the same time effectively ensure the stability of PVC product colors, accurately match the production needs of the PVC industry, and enhance the market competitiveness of enterprises. Attached Figure Description
[0031] Figure 1 This is a flowchart of the color detection method for pigments according to the present invention.
[0032] Figure 2 These are physical images of the standard sample and the sample to be tested in the examples of this invention.
[0033] Figure 3 It is the colorimetric card in the example of this invention. Detailed Implementation
[0034] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.
[0035] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, in which numerous illustrative embodiments are shown. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described below in more detail, can be implemented in any of a number of ways.
[0036] The colors mentioned in this invention refer to colors in their conventional literal sense in the art. For example, white pigment refers to pigment that appears white to the naked eye; other colors besides white and black can be collectively referred to as colored pigments.
[0037] It should be clarified that color is not a single specific color, but a collection of various colors that are neither white nor black, such as purple, yellow, and red.
[0038] Based on the above color classification, the present invention divides the pigments to be detected into three categories: white, black, and colored, and the pigments can be presented in various forms (such as powder, flakes, etc.); among them, pigments in powder form can be called pigment powder, and pigments in flake form can be called pigment flakes.
[0039] Since the color hue testing process requires a comprehensive test of the color development effect of the colorant in PVC film, and PVC film can be divided into transparent and opaque states according to actual needs, it is necessary to test the color development effect of the colorant in PVC film in both states separately.
[0040] The concentration test piece referred to in this invention is a transparent test piece with a relatively high pigment concentration; the light-colored test piece refers to an opaque test piece with a diluted pigment concentration that is lower than that of the concentration test piece.
[0041] In this invention, all situations are covered by the description of the standard / test without explicit labeling; for example, when a dark-colored test piece is mentioned alone, it refers to the standard dark-colored test piece or the dark-colored test piece to be tested.
[0042] In a preferred embodiment of the present invention, a method for detecting the hue of a pigment is provided, comprising the following steps:
[0043] The PVC resin mixture powder and standard colorant, and the PVC resin mixture powder and the colorant to be tested were mixed evenly using an open mill. Then, the mixtures were drawn into pieces to obtain the corresponding standard dark color test pieces and the dark color test pieces.
[0044] The PVC resin mixture powder, standard colorant, and opaque colorant are mixed evenly using an open mill, as are the PVC resin mixture powder, the colorant to be tested, and the opaque colorant. Then, the mixtures are drawn to obtain corresponding standard light-colored test pieces and light-colored test pieces. The opaque colorant includes purple or white colorant.
[0045] Place the standard dark color test piece and the dark color test piece to be tested side by side, and place the standard light color test piece and the light color test piece to be tested side by side to form a colorimetric card;
[0046] Visual observation was used to compare the colors of the standard dark color test piece and the dark color test piece to be tested, as well as the colors of the standard light color test piece and the light color test piece to be tested, on the colorimetric chart.
[0047] A colorimeter was used to test the standard dark color test piece, the dark color test piece to be tested, the standard light color test piece, and the light color test piece to be tested, respectively, to obtain the color difference parameter △E1 of the dark color test piece to be tested relative to the standard dark color test piece, and the color difference parameter △E2 of the light color test piece to be tested relative to the standard light color test piece.
[0048] If the visual observation results show that the corresponding test pieces are similar in color, and both △E1≤0.8 and △E2≤0.8 are satisfied, then the colorant to be tested is deemed qualified.
[0049] In the optional examples, the selection rules for opaque pigments are as follows:
[0050] When the standard pigment and the pigment to be tested are both white, the opaque pigment is purple.
[0051] When the standard pigment and the pigment to be tested are both black, the opaque pigment is white.
[0052] When the standard pigment and the pigment to be tested are colors other than white and black, the opaque pigment is white.
[0053] In an optional example, when the standard pigment and the pigment to be tested are both white, the amount of the standard pigment added is 4% to 5% of the mass of the PVC resin mixture powder, and the amount of the pigment to be tested added is 4% to 5% of the mass of the PVC resin mixture powder.
[0054] In an optional example, when the color of the standard pigment and the pigment to be tested is black, the amount of the standard pigment added is 0.5% to 1% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 0.5% to 1% of the mass of the PVC resin mixed powder.
[0055] In an optional example, when the standard pigment and the pigment to be tested are colors other than white and black, the amount of standard pigment added is 1% to 2% of the mass of the PVC resin mixture powder, and the amount of pigment to be tested added is 1% to 2% of the mass of the PVC resin mixture powder.
[0056] In an optional example, the amount of white pigment added is 4% to 5% of the mass of the PVC resin mixture powder.
[0057] In an optional example, the amount of purple pigment added is 0.3% to 0.5% of the mass of the PVC resin mixture powder.
[0058] In an optional example, the colorimetric chart includes the following preparation process:
[0059] Cut samples of the same size from the standard dark-colored test piece, the dark-colored test piece to be tested, the standard light-colored test piece, and the light-colored test piece to be tested. The cut samples of the same size should be consistent for each test piece. It is also necessary to ensure that the sampling position of all samples is the same, the sampling direction is consistent, and the front and back of the samples are facing the same.
[0060] The standard dark-colored test piece and the test dark-colored test piece are fixed side by side, and the standard light-colored test piece and the test light-colored test piece are fixed side by side, ensuring that the front and back sides of each corresponding test piece are aligned and the warp and weft directions are aligned, to obtain a colorimetric card.
[0061] In the optional example, the sample dimensions are: length × width not less than 6.5cm × 4.5cm, and the thickness difference between all samples does not exceed 0.005mm.
[0062] In the optional example, the wheel temperature of the open mill is 170℃±2℃, the mixing time is 3min±5s, and the thickness of each prepared test piece is 0.25mm.
[0063] In an optional example, the components of the PVC resin mixture powder, by weight, include: 100 parts of p-1000 type PVC resin, 3 parts of DINP plasticizer, 3 parts of soybean oil, 40 parts of DOP plasticizer, and 2 parts of 139 stabilizer; it is understood that the components of the PVC resin mixture powder can be adjusted according to actual needs.
[0064] The standard pigment referred to in this invention refers to the reference pigment initially determined according to production requirements. Technicians can retain a batch of initial pigments as standard pigments. When the batch of standard pigments is exhausted, the next batch of standard pigments can be re-determined through the hue detection method of this invention, and it must be ensured that the color difference parameter △E between the new batch of standard pigments and the original standard pigments is ≤0.5.
[0065] Below, in conjunction with Figure 1 As shown, we will further explain the technical solution of the present invention based on the color classification of the pigment to be detected, and with specific examples.
[0066] The colorant to be tested is colored.
[0067] The quality ratio of colored pigments is shown in Table 1:
[0068] Table 1
[0069] The components of the PVC resin mixture powder are shown in Table 2:
[0070] Table 2
[0071] (1) Preparation of test pieces
[0072] Clean the open mill with PVC resin mixed powder, then pour 50g of PVC resin mixed powder into the small two-roll mill for basic mixing and shaping. After adding the standard / test colorant, try to ensure that there is no accumulation of the standard / test colorant before adding the tape and mixing evenly. At the same time, measure the thickness. After 3 minutes, take out the test piece. Because some colorants precipitate more severely on the machine surface, the open mill should be cleaned after each sample extraction.
[0073] Following the above method, standard dark-colored test pieces, test dark-colored test pieces, standard light-colored test pieces, and test light-colored test pieces are prepared sequentially.
[0074] (2) Preparation of colorimetric cards
[0075] Take samples of approximately 4.5cm × 6.5cm in size and 0.25mm ± 0.01mm in thickness from each prepared test piece. The thickness difference of the samples should not exceed 0.005mm. The sampling positions should be roughly the same, the warp and weft directions should be consistent, and the front and back sides of the adhesive tape should be consistent.
[0076] Place the samples on the data card in the order of left (standard) and right (to be tested). The two samples should be placed on the same side and in the same direction (warp and weft), with the gap as small as possible to facilitate color matching. A line about 1 mm thick can be drawn on the dark-colored sample with a black pen to compare the occlusion rate.
[0077] (3) Result determination
[0078] Using visual observation, under the same occlusion rate (the black line has the same color depth on both dark and light-colored samples), the colors of the standard dark-colored sample and the dark-colored sample to be tested, as well as the colors of the standard light-colored sample and the light-colored sample to be tested, were compared on the colorimetric chart.
[0079] A colorimeter was used to test the standard dark color test piece, the dark color test piece to be tested, the standard light color test piece, and the light color test piece to be tested, respectively, to obtain the color difference parameter △E1 of the dark color test piece to be tested relative to the standard dark color test piece, and the color difference parameter △E2 of the light color test piece to be tested relative to the standard light color test piece.
[0080] If the visual observation results show that the corresponding test pieces are similar in color, and both △E1≤0.8 and △E2≤0.8 are satisfied, then the colorant to be tested is deemed qualified.
[0081] The colorant to be tested is white.
[0082] The quality ratio of white pigment is shown in Table 3:
[0083] Table 3
[0084] Since white pigment is white in nature, if no purple pigment is added when preparing the test piece, the resulting test piece will be white, making it difficult to accurately distinguish its quality through data detection and visual observation. However, by adding an appropriate amount of purple pigment to the white pigment, the color difference of the test piece can be effectively highlighted, thereby significantly improving the accuracy and convenience of distinguishing the quality of the white pigment.
[0085] The composition of the PVC resin mixture powder is shown in Table 2.
[0086] Then, the color of the pigment can be detected by following the steps (1) to (3) above.
[0087] The pigment to be tested is black.
[0088] The quality ratio of black pigment is shown in Table 4:
[0089] Table 4
[0090] Since black pigment is black in nature, if white pigment is not added for dilution during the preparation of the test piece, the resulting test piece will have an excessively high color concentration and be pure black, making it difficult to accurately judge the quality of the black pigment through data detection and visual observation. However, after adding an appropriate amount of white pigment to the black pigment, the film will appear gray, and the quality of the black pigment can be effectively distinguished through data detection and visual observation.
[0091] The composition of the PVC resin mixture powder is shown in Table 2.
[0092] Then, the color of the pigment can be detected by following the steps (1) to (3) above.
[0093] To facilitate better understanding, the present invention will be further described below with reference to specific examples, but the preparation process is not limited to this, and the content of the present invention is not limited thereto.
[0094] Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.
[0095] 1. Equipment and Instruments
[0096] Open mill;
[0097] Digital surface thermometer, measuring range 0℃-200℃, scale division 0.1℃;
[0098] Thickness gauge, measuring range 0mm-10mm, graduation value 0.01mm;
[0099] Electronic balance, with an accuracy of 0.1 mg and 0.1 g;
[0100] Stopwatch, accuracy 0.2s;
[0101] Color difference meter Datar DC-600.
[0102] 2. The white and purple color flakes are manufactured by Dagong Fine Chemical (Kunshan) Co., Ltd., with model numbers QW036H and QR121H respectively.
[0103] 3. The composition of the PVC resin mixture powder is shown in Table 2.
[0104] 4. The colorant to be tested is a colored color chip, such as... Figure 2 As shown.
[0105] 5. The testing process is as follows:
[0106] Step 1: Sample Preparation
[0107] First, weigh the standard pigment, the pigment to be tested, the white pigment, and the purple pigment according to the ratio of ±0.0005g. Then weigh 50.0g of the mixed powder and set it aside for later use.
[0108] Clean the open mill with PVC resin mixed powder, then pour 50g of PVC resin mixed powder into the small two-roll mill for basic mixing and shaping. After adding the standard / test colorant, try to ensure that there is no accumulation of the standard / test colorant before adding the tape and mixing evenly. At the same time, measure the thickness. After 3 minutes, take out the test piece. Because some colorants precipitate more severely on the machine surface, the open mill should be cleaned after each sample extraction.
[0109] Following the above method, standard dark-colored test pieces, test dark-colored test pieces, standard light-colored test pieces, and test light-colored test pieces are prepared sequentially.
[0110] Step 2: Preparation of colorimetric cards
[0111] Take samples of approximately 4.5cm × 6.5cm in size and 0.25mm ± 0.01mm in thickness from each prepared test piece. The thickness difference of the samples should not exceed 0.005mm. The sampling positions should be roughly the same, the warp and weft directions should be consistent, and the front and back sides of the adhesive tape should be consistent.
[0112] like Figure 3 As shown, place the standard on the left and the test sample on the right on the data card. When placing the two samples, the front and back sides should be consistent, the warp and weft directions should be consistent, and the gap should be as small as possible to facilitate color matching. A line about 1 mm thick can be drawn on the dark-colored sample with a black pen to compare the occlusion rate.
[0113] Step 3, Result Determination
[0114] Using visual observation, under the same occlusion rate (the black line has the same color depth on both dark and light-colored samples), the colors of the standard dark-colored sample and the dark-colored sample to be tested, as well as the colors of the standard light-colored sample and the light-colored sample to be tested, were compared on the colorimetric chart.
[0115] like Figure 3 As shown, through visual observation, the dark-colored sample 1 is more yellow than the standard sample, while sample 2 is closer to the standard sample; the light-colored sample 1 and sample 2 are both close to the color of their corresponding standard samples.
[0116] A colorimeter (instrument settings: colorimeter D65 light source; reflection / transmission: select reflection; specular light: select SCI; test area: select LAV (25.4MM); UV setting: select 100% complete) was used to test the standard dark color sample, the dark color sample to be tested, the standard light color sample, and the light color sample to be tested, respectively. The color difference parameter △E1 of the dark color sample to be tested relative to the standard dark color sample, and the color difference parameter △E2 of the light color sample to be tested relative to the standard light color sample were obtained.
[0117] The results are shown in Table 5.
[0118] Table 5
[0119] Note: Color data is represented by three axes: L, A, and B. L represents black and white, A represents red and green, and B represents blue and yellow.
[0120] △E: Calculated by the differences between the three values of sample and standard (reference) LAB: △L, △A, △B; △L = Lsample - Lstandard, △A = Asample - Astandard, △B = Bsample - Bstandard, △E = SQRT(△L squared + △A squared + △B squared).
[0121] The test results show that △E1=1.16>0.8 and △E2=1.10>0.8 for sample 1. Based on the visual observation results, it can be determined that sample 1 is unqualified.
[0122] For sample 2, ΔE1 = 0.72 < 0.8 and ΔE2 = 0.55 < 0.8. Based on visual inspection, sample 2 can be determined to be qualified.
[0123] Combination Figure 2 As shown, judging solely from the appearance of the pigments to be tested, both Sample 1 and Sample 2 are very similar to the standard pigments, making it impossible to distinguish the color changes of the pigments to be tested, thus failing to identify defective products and causing production waste.
[0124] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.
Claims
1. A method for detecting the hue of a pigment, characterized in that, Includes the following steps: The PVC resin mixture powder and standard colorant, and the PVC resin mixture powder and the colorant to be tested were mixed evenly using an open mill. Then, the mixtures were drawn into pieces to obtain the corresponding standard dark color test pieces and the dark color test pieces. The PVC resin mixture powder, standard colorant, and opaque colorant are mixed evenly using an open mill, as are the PVC resin mixture powder, the colorant to be tested, and the opaque colorant. Then, the mixtures are drawn to obtain corresponding standard light-colored test pieces and light-colored test pieces. The opaque colorant includes purple or white colorant. Place the standard dark color test piece and the dark color test piece to be tested side by side, and place the standard light color test piece and the light color test piece to be tested side by side to form a colorimetric card; Visual observation was used to compare the colors of the standard dark color test piece and the dark color test piece to be tested, as well as the colors of the standard light color test piece and the light color test piece to be tested, on the colorimetric chart. A colorimeter was used to test the standard dark color test piece, the dark color test piece to be tested, the standard light color test piece, and the light color test piece to be tested, respectively, to obtain the color difference parameter △E1 of the dark color test piece to be tested relative to the standard dark color test piece, and the color difference parameter △E2 of the light color test piece to be tested relative to the standard light color test piece. If the visual observation results show that the corresponding test pieces are similar in color, and both △E1≤0.8 and △E2≤0.8 are satisfied, then the colorant to be tested is deemed qualified.
2. The method for detecting the hue of a pigment according to claim 1, characterized in that, The selection rules for the opaque pigment are as follows: When the standard pigment and the pigment to be tested are both white, the opaque pigment is a purple pigment; When the standard pigment and the pigment to be tested are both black, the opaque pigment is white. When the standard pigment and the pigment to be tested are colors other than white and black, the opaque pigment is a white pigment.
3. The method for detecting the hue of a pigment according to claim 1, characterized in that, When the standard pigment and the pigment to be tested are both white, the amount of the standard pigment added is 4% to 5% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 4% to 5% of the mass of the PVC resin mixed powder.
4. The method for detecting the hue of a pigment according to claim 1, characterized in that, When the standard pigment and the pigment to be tested are both black, the amount of the standard pigment added is 0.5% to 1% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 0.5% to 1% of the mass of the PVC resin mixed powder.
5. The method for detecting the hue of a pigment according to claim 1, characterized in that, When the standard pigment and the pigment to be tested are colors other than white and black, the amount of the standard pigment added is 1% to 2% of the mass of the PVC resin mixed powder, and the amount of the pigment to be tested added is 1% to 2% of the mass of the PVC resin mixed powder.
6. The method for detecting the hue of a pigment according to claim 1, characterized in that, The amount of white pigment added is 4% to 5% of the mass of the PVC resin mixed powder.
7. The method for detecting the hue of a pigment according to claim 1, characterized in that, The amount of purple pigment added is 0.3% to 0.5% of the mass of the PVC resin mixed powder.
8. The method for detecting the hue of a pigment according to claim 1, characterized in that, The colorimetric chart includes the following production process: Cut samples of the same size from the standard dark-colored test piece, the dark-colored test piece to be tested, the standard light-colored test piece, and the light-colored test piece to be tested. The cut samples of the same size should be consistent for each test piece. It is also necessary to ensure that the sampling position of all samples is the same, the sampling direction is consistent, and the front and back of the samples are facing the same. The standard dark-colored test piece and the test dark-colored test piece are fixed side by side, and the standard light-colored test piece and the test light-colored test piece are fixed side by side, ensuring that the front and back sides of each corresponding test piece are aligned and the warp and weft directions are aligned, to obtain a colorimetric card.
9. The method for detecting the hue of a pigment according to any one of claims 1-8, characterized in that, The components of the PVC resin mixture powder, by weight, include: 100 parts of p-1000 type PVC resin, 3 parts of DINP plasticizer, 3 parts of soybean oil, 40 parts of DOP plasticizer, and 2 parts of 139 stabilizer.
10. The method for detecting the hue of a pigment according to any one of claims 1-8, characterized in that, The open mill has a wheel temperature of 170℃±2℃ and a mixing time of 3min±5s. The thickness of each prepared test piece is 0.25mm.