Master batch optimization method based on laser etching technology and application

Abstract

The invention relates to the field of laser etching processing, and particularly discloses a color optimization method based on a laser etching technology. The method comprises the steps that the internal proportion of a toner system is adjusted, laser etching machining parameters (including the speed of 500-1300 mm / min, the frequency of 30% and the power of 20 kHz) are optimized, the Lab value and the chromatic aberration (delta E) with porcelain white are monitored in real time, and the machining conditions are dynamically fed back and adjusted, so that accurate control over color shift after laser etching is achieved. The invention can effectively solve the problem of yellowish color in laser etching processing, and obviously improve the brightness and uniformity of the surface color of the product. Compared with the prior art, the PP master batch has the advantages of being flexible in color regulation and control, economical, efficient and high in adaptability, and is suitable for laser carving machining of household appliance shells, automotive upholstery and other PP master batch products.

Description

Technical Field

[0001] The invention relates to the field of laser engraving, and in particular to a method for controlling color change by adjusting laser engraving parameters and optimizing color matching, and is applicable to color control technology in laser engraving of plastic product surfaces. Background Art

[0002] Laser engraving technology is widely used in the field of marking and decoration of plastic products due to its high efficiency and precision. However, in actual application, laser engraving processing often causes significant changes in surface color, which is affected by many factors such as processing speed, power and raw material ratio. For example, under the condition of high processing speed, the surface of the product is prone to increase in brightness and yellow shift, which may affect the appearance quality of the product.

[0003] The existing technology lacks an effective solution that can dynamically adjust the color change during the laser engraving process. Therefore, there is an urgent need for a method that can optimize the color performance to meet actual production needs. Summary of the invention

[0004] The purpose of the present invention is to provide a color optimization method based on laser engraving technology, which can effectively control the color change by adjusting the processing parameters and raw material formula, especially solve the problem of yellowing of products after laser engraving.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A color optimization method based on laser engraving is suitable for surface processing control of polypropylene (PP) masterbatch products. By optimizing the raw material formula, adjusting the processing parameters and dynamically monitoring the color change, the problem of surface color deviation of the product after laser engraving can be effectively solved. The key components and parameters of the present invention include:

[0007] 1. Base material:

[0008] Polypropylene (PP) masterbatch, made of copolymerized polypropylene, has excellent mechanical properties and thermal stability.

[0009] 2. Colorants:

[0010] Toner 1: used to neutralize the yellow shift on the surface after laser engraving, preferably with a mass fraction of 20-100%;

[0011] Toner 2: used to adjust the red balance of the color, preferably with a mass fraction of 10-50%;

[0012] 3. Laser engraving processing parameters:

[0013] Speed: The preferred range is 800-1100 mm / min;

[0014] Frequency: set to 30%;

[0015] Power: 20kHz is preferred.

[0016] 4.Lab color change monitoring:

[0017] Use the Lab color measurement system to record the L (brightness), a (red and green components), and b (yellow and blue components) values ​​before and after engraving in real time;

[0018] Lab value change control range: ΔL (brightness difference): 10-30; Δa (red-green difference): 0.5-1.5; Δb (yellowness difference): 5-8.

[0019] 5. Color difference calculation

[0020] The general color difference calculation formula is:

[0021] The smaller △E is, the closer the color difference is to the standard porcelain white.

[0022] The color optimization method of the present invention comprises the following steps:

[0023] Step 1: Mix PP masterbatch, color powder 1 and color powder 2 in a certain proportion. Stir in a high-speed mixer for 4-6 minutes to prepare a uniform mixture.

[0024] Step 2: The above mixture is extruded into granules and a sample is prepared through a twin-screw extruder. The temperature zones of the extruder are set as follows: the processing temperatures in zone IX are 220°C, 230°C, 230°C, 230°C, 230°C, 230°C, 220°C, 210°C, and 210°C respectively; the main screw speed is 400-500r / min; and the water tank cooling temperature is controlled at 20°C-30°C.

[0025] Step 3: Use laser engraving equipment to process the surface of the sample. The specific parameters are: laser engraving speed is set to 800-1100mm / min; frequency is set to 30%; power is set to 20kHz.

[0026] Step 4: Use a Lab colorimeter to monitor the change in Lab value before and after processing, and record the ΔL, Δa, and Δb values ​​to determine whether the color change meets the following control range: ΔL value: 10-30; Δa value: 0.5-1.5; Δb value: 5-8.

[0027] If the Δb value exceeds the control range, it can be compensated by adjusting the ratio of toner 1 and toner 2 in the raw material, or increasing the laser engraving speed to make corrections. Ultimately, the actual color difference is smaller.

[0028] Step 5: Optimize processing conditions based on feedback to ultimately obtain products with uniform color and appropriate brightness.

[0029] Compared with the prior art, the present invention has the following technical advantages:

[0030] 1. Strong color controllability: Through real-time monitoring and feedback adjustment of Lab values, the color deviation after laser engraving can be effectively controlled.

[0031] 2. Wide adaptability: Suitable for laser engraving processing scenarios of various PP masterbatch products, including plastic packaging, home appliance housings, automotive interior parts, etc.

[0032] 3. Economical and efficient: Through the optimization of raw materials and processing parameters, high-quality color performance can be achieved while reducing production costs.

[0033] 4. Dynamic adjustment mechanism: Dynamically adjust the ratio of toner 1 and toner 2 and the dynamic feedback mechanism to significantly reduce product quality problems caused by yellowing and improve production efficiency. DETAILED DESCRIPTION

[0034] Below in conjunction with specific embodiment, further elaborate content of the present invention.It should be emphasized that these embodiments are only used for further explanation of the present invention, and can not be interpreted as limiting the scope of protection of the present invention.In addition, it should be understood that after reading the content described in the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

[0035] Example 1. Color change of PP masterbatch during laser engraving

[0036] 1. Experimental Materials

[0037] ·Base material: polypropylene (PP) masterbatch;

[0038] Colorant: color powder 3, mass fraction is 10-80%;

[0039] Auxiliary toner: No other additives, only test the laser engraving effect of the masterbatch.

[0040] 2. Processing parameters

[0041] Laser engraving speed: 500-1200mm / min;

[0042] Frequency: 30%

[0043] Power: 20kHz.

[0044] 3. Experimental Procedure

[0045] 1. Use color powder 3, mix it into PP masterbatch in a certain proportion, and prepare test samples after evenly dispersing;

[0046] 2. Process the test samples at different speeds in the laser engraving equipment;

[0047] 3. Record the color Lab value and its changes before and after laser engraving, where ΔL, Δa, Δb are the differences before and after engraving, and ΔE is calculated by comparing the value after engraving with the porcelain white.

[0048] 4. Experimental Results

[0049] Laser engraving speed (mm / min) L (after engraving) a (after engraving) b (after engraving) ΔL Δa Δb ΔE

[0050]

[0051] 5. Analysis and Conclusion

[0052] 1. Brightness change (L value):

[0053] οAs the speed gradually increases from 500mm / mm to 900mm / min, the L value (brightness) increases significantly;

[0054] οThe brightness reaches the highest value (L=54.65) at 900 mm / min, then gradually decreases, and the brightness drops significantly at 1200 mm / min.

[0055] 2. Red and green components (a value):

[0056] At lower speeds (500-800 mm / min), the a value continues to be positive (reddish), and at 900

[0057] mm / min and then gradually decreases to approach zero at 1200 mm / min.

[0058] 3. Yellow-blue component (b value):

[0059] The οb value continued to rise in the range of 500-700 mm / min, reached a peak value (b=9.99) at 800 mm / min, and then gradually decreased, and significantly decreased to 4.65 at 1200 mm / min.

[0060] 4. Color difference (ΔE value):

[0061] The color difference gradually decreases with the increase of speed, reaching the optimal value (△E=36.40) at 900 mm / min, and then begins to rebound, rising to 43.09 at 1200 mm / min.

[0062] 5. Summary:

[0063] οRecommended speed range: 800-900mm / min. Within this range, the brightness (L value) is high, the red and yellow shifts are moderate, and the color difference with the target porcelain white is minimal:

[0064] ο Optimization suggestions: For processing conditions with speeds exceeding 900 mm / min, it is recommended to optimize process parameters (such as power) or add auxiliary toners (toner 1 and 2) to further neutralize the yellowing phenomenon.

[0065] Example 2: Effect of processing speed on color change of PP masterbatch

[0066] 1. Experimental materials:

[0067] Matrix material: PP masterbatch;

[0068] Colorant: Same as in Example 1, using toners 1 and 2.

[0069] 2. Processing parameters:

[0070] 3. Laser engraving speed: set to 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300mm / min;

[0071] 4. Other parameters remain unchanged: frequency 30%, power 20kHz.

[0072] 5. Experimental results:

[0073]

[0074] 6. Analysis and conclusion:

[0075] Low speed conditions (500-600mm / min):

[0076] The ΔL value gradually increases, indicating that the surface brightness increases and the color tends to be white;

[0077] The Δa value is close to 0 or slightly positive (redder), and the Δb value increases rapidly (yellower), indicating that the yellow shift is more significant;

[0078] The color difference (ΔE) is large (52.08 at 500 mm / min and 44.51 at 600 mm / min), indicating that the color in this speed range is far from the target porcelain white.

[0079] Medium speed conditions (700-800mm / min):

[0080] The ΔL value continues to increase, the brightness reaches a higher level, and the surface color is closest to the target white;

[0081] The Δa value starts to become negative (greener), and the Δb value remains high (yellower), but the yellow shift is relatively stable;

[0082] The color difference (ΔE) is the smallest (39.89 at 700 mm / min, 37.36 at 800 mm / min), and the color within this range is closest to the target porcelain white.

[0083] High speed conditions (900-1200mm / min):

[0084] The ΔL value is close to the maximum value at 900-1000 mm / min, but starts to decrease (brightness decreases) after 1100 mm / min, and the color tends to be darker;

[0085] The Δa and Δb values ​​decrease, and the yellow shift weakens, but the surface color is overall cooler and deviates from the target white;

[0086] The color difference (ΔE) gradually increases after 900 mm / min (37.73 at 900 mm / min and 42.66 at 1200 mm / min), indicating that the color deviates from the porcelain white color more sharply when the speed is too high.

[0087] Conclusion and Recommendations

[0088] The laser engraving speed has a significant impact on the color change and color difference of the PP masterbatch surface;

[0089] ·Recommended processing speed range: 700-900mm / min. Within this range, the brightness (L value) is higher, the color difference (ΔE) is the smallest, and the color is closest to the target porcelain white;

[0090] When the speed exceeds 900 mm / min, although the brightness is still high, the color difference (ΔE) gradually increases and the surface color deviates from the target white;

[0091] Optimization direction: Further optimize the yellow shift by adjusting the ratio of Toner 1 and Toner 2 within the recommended speed range, while controlling the color difference value (ΔE) within 40 to achieve the best effect.

[0092] Experimental Example 3: Effect of laser frequency on color change during laser engraving of PP masterbatch

[0093] 1. Experimental Materials

[0094] ·Base material: polypropylene (PP) masterbatch;

[0095] Colorant: Color powder 3, mass fraction is 10-80%.

[0096] 2. Processing parameters

[0097] Laser engraving speed: 900mm / min

[0098] Laser frequency: set to 20kHz, 30kHz, 40kHz, 50kHz, 60kHz.

[0099] 3. Experimental Procedure

[0100] 1. Use color powder 3 to mix with PP masterbatch in a certain proportion, and prepare test samples after uniform dispersion;

[0101] 2. Use laser processing samples with different frequencies;

[0102] 3. Measure and record the Lab value before and after laser engraving and the color difference (ΔE) with the target porcelain white.

[0103] 4. Experimental Results

[0104]

[0105] 5. Analysis and Conclusion

[0106] 1. Brightness change (L value):

[0107] οAt the frequency of 20kHz, the L value is 55.22, which is the highest brightness;

[0108] οAs the frequency increases, the L value gradually decreases, dropping to 52.81 at a frequency of 30kHz and to 52.58 at a frequency of 60kHz.

[0109] 2. Red and green components (a value):

[0110] The οa value is small at 20kHz (a=0.82), increases slightly with increasing frequency, and reaches a maximum value at 50kHz (a=1.02).

[0111] 3. Yellow-blue component (b value):

[0112] The OB value is positive (yellowish) in all frequency ranges and does not change much as the frequency increases, ranging from 6.63 to 7.90.

[0113] 4. Color difference (ΔE value):

[0114] οThe color difference is the smallest at 20kHz (ΔE=35.55), indicating that the color is closest to the target porcelain white at this frequency;

[0115] οAs the frequency increases, the color difference gradually increases, which is 38.14 at 30kHz and 53.79 at 50kHz.

[0116] 5. Recommended frequency:

[0117] οThe recommended frequency is 20kHz. At this frequency, the brightness is maximum, the reddish (a value) and yellowish (b value) are well controlled, and the color difference (ΔE value) is minimum.

[0118] 6. Optimization direction:

[0119] ο Further adjustment of processing speed or power on the basis of the recommended frequency of 20kHz may further improve color closeness.

[0120] Example 4: Effect of frequency on color change during laser engraving of PP masterbatch

[0121] 1. Experimental Materials

[0122] ·Base material: polypropylene (PP) masterbatch;

[0123] Colorant: Color powder 3, mass fraction is 10-80%.

[0124] 2. Processing parameters

[0125] Laser engraving speed: 900mm / min;

[0126] Power: 20kHz;

[0127] Frequency: Set to 30%, 50%, 80%, 100%.

[0128] 3. Experimental Procedure

[0129] 1. Mix PP masterbatch and color powder 3 in proportion and prepare test samples after uniform dispersion;

[0130] 2. Process the samples at different frequencies on the laser engraving equipment;

[0131] 3.Measure and record the Lab value and changes before and after laser engraving.

[0132] 4. Experimental Results

[0133] frequency(%) L(after engraving) a(after engraving) B(after engraving) △L △a △b △E 30 55.23 0.99 8.06 27.66 0.93 8.69 35.86 50 54.28 1.06 8.26 26.71 1.00 8.89 36.83 80 55.09 0.93 7.70 27.52 0.87 8.33 35.91 100 54.02 0.90 7.57 26.45 0.84 8.20 36.92

[0134] 5. Analysis and Conclusion

[0135] 1. Brightness change (L value):

[0136] οAt 30% frequency, the L value reaches 55.23, which is the highest brightness, indicating that the surface brightness improvement effect is best at this frequency;

[0137] οAs the frequency increases, the L value gradually decreases and drops to 54.02 at 100% frequency.

[0138] 2. Red and green components (a value):

[0139] The a value is positive (reddish) in the frequency range of 30%-100%, but the higher the frequency, the smaller the a value (the reddish trend weakens).

[0140] 3. Yellow-blue component (b value):

[0141] The οb value is 8.06 at 30% frequency, showing a certain yellow shift;

[0142] As the frequency increases, the b value gradually decreases, decreasing to 7.57 at 100% frequency, but the color brightness also decreases.

[0143] 4. Color difference (ΔE value):

[0144] οThe color difference at 30% frequency is 35.86, which is the minimum value, indicating that the color is closest to the target porcelain white at this frequency;

[0145] οAs the frequency increases, the color difference gradually increases, reaching 36.92 at 100% frequency.

[0146] 5. Recommended frequency:

[0147] ο30% frequency has the best effect. At this frequency, the brightness (L value) is the highest and the color difference (△E) is

[0148] The reddish (a value) and yellowish (b value) phenomena are well controlled.

[0149] 6. Optimization direction:

[0150] ο Based on the recommended frequency of 30%, appropriately reduce the laser engraving speed or add blue masterbatch to further reduce the b value (yellow offset).

[0151] The experimental results show that at a speed of 900 mm / min and a power of 20 kHz, a frequency of 30% is the optimal choice, which helps to achieve a processing effect with maximum brightness and minimum color shift.

[0152] Example 5: Optimization of PP laser engraving changes by adjusting the toner ratio (other conditions determined)

[0153] 1. Experimental Materials

[0154] ·Base material: PP masterbatch;

[0155] Colorant formula:

[0156] οFormula 1: 20%-60% color powder 3 + 30%-50% color powder 1 + 10%-30% color powder 2;

[0157] οFormula 2: 20%-60% color powder 3 + 20%-40% color powder 1 + 20%-40% color powder 2;

[0158] οFormula 3: 40%-80% color powder 3 + 10%-30% color powder 1 + 10%-30% color powder 2.

[0159] 2. Processing parameters

[0160] Laser engraving speed: 900mm / min;

[0161] Frequency: 30%

[0162] Power: 20kHz.

[0163] 3. Experimental results

[0164]

[0165] 4. Analysis and Conclusion

[0166] 1. Formula 1 (20%-60% color powder 3 + 30%-50% color powder 1 + 10%-30% color powder 2):

[0167] οThe brightness (ΔL=29.19) is higher, but the yellow shift (Δb=8.56) is most obvious;

[0168] ο The color difference (ΔE=36.40) is relatively low, but the yellow shift is prominent;

[0169] ο Toning suggestion: Increase the proportion of Toner 1 to further neutralize the yellow color.

[0170] 2. Formula 2 (20%-60% toner 3 + 20%-40% toner 1 + 20%-40% toner 2):

[0171] οThe brightness (ΔL=25.39) is moderate, and the yellow shift is well controlled (Δb=6.51);

[0172] οThe color difference (ΔE=39.42) is slightly higher, but the overall effect is balanced;

[0173] ο Color grading advice: Performs well in most scenes and is suitable as a base recipe.

[0174] 3. Formula 3 (40%-80% toner 3 + 10%-30% toner 1 + 10%-30% toner 2):

[0175] ο Brightness (ΔL=24.49) is slightly lower than that of recipe 2;

[0176] ο Yellow color shift (Δb=7.79) is between formulation 1 and formulation 2;

[0177] οThe color difference (ΔE=40.51) is the largest, but the overall color performance is acceptable;

[0178] ο Color grading suggestion: Suitable for scenes with low brightness requirements but high requirements for color balance.

[0179] Summary and Recommendations

[0180] 1. Recommended formula:

[0181] οFormula 2 is suitable for scenes with strict requirements on yellow shift, with balanced performance and moderate brightness;

[0182] οFormula 3 is suitable for scenes that require overall balanced brightness and soft visual performance.

[0183] 2. Optimization direction:

[0184] For formulas with obvious yellow shift (such as formula 1), the proportion of toner 1 can be appropriately increased.

[0185] οIn actual production, the laser engraving speed and power can be further adjusted to optimize the proximity between the Lab value and the target porcelain white color.

[0186] The present invention provides a method for optimizing the color of polypropylene (PP) masterbatch products based on laser engraving technology. By adjusting the raw material ratio and optimizing the laser engraving processing parameters (including speed, frequency and power), accurate control of the color change after processing is achieved. The present invention further introduces a real-time monitoring and feedback adjustment mechanism of Lab values, which can dynamically adjust the color deviation, especially effectively solve the problem of yellowing of the surface of the product after laser engraving. Experimental verification shows that the method of the present invention is applicable to a variety of PP masterbatch products, has the advantages of strong color controllability, wide adaptability, economic efficiency, etc., can significantly improve the appearance quality of the product, and meet actual production needs.

[0187] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined by the claims.

Claims

1. A color optimization method based on laser engraving technology, characterized in that: The following steps are involved: (1) Raw material ratio adjustment: adjust the concentration of the toner system in the masterbatch to adjust the color shift, where the mass fraction of toner 1 is 20.100% and the mass fraction of toner 2 is 10%-50%; (2) Processing parameter setting: Set the laser engraving processing speed within the range of 500-1300 mm / min, preferably 800-1100 mm / min, and set the frequency to 20-30% and the power to 20 kHz; (3) Color data monitoring: Use color measurement equipment to monitor the Lab value of the product surface before and after engraving in real time; calculate the color difference ΔE with porcelain white through the Lab value; ΔL, Δa, Δb are compared with the L, a, b values ​​before engraving, and ΔE is compared with porcelain white. The Lab values ​​of porcelain white are 90, -0.3, and 3 respectively; (4) Color change range control: According to the change of Lab value, adjust the processing parameters to meet the following conditions: ΔL value (brightness difference): 10-30; Δa value (red-green difference): 0.5-1.5; Δb value (yellowness difference): 5-8; (5) Feedback color optimization: When the Δb value exceeds 8, the product color performance is optimized by increasing the blue and red components or reducing the yellow offset.

2. The color optimization method based on laser engraving technology according to claim 1, characterized in that: The raw material adjustment is completed by the following steps: (1) According to the color requirements of the target product, the proportion of toner 1 is increased to neutralize the yellow shift; (2) When the Δb value is greater than 8 and the Δa value is less than 0, add toner 1 and toner 2 to make a complementary color adjustment.

3. The color optimization method based on laser engraving technology according to claim 1, characterized in that: The monitoring accuracy of the Lab value is: the L value accuracy is within 0.1; the a value and b value accuracy are both within 0.

01.

4. A color optimization method based on laser engraving technology according to claim 1 or 2, characterized in that: The power of the laser engraving processing equipment is 20kHz, the frequency is 30%, and the processing speed is 900mm / min.

5. A color optimization method based on laser engraving technology according to any one of claims 1 to 3, characterized in that: The color optimization method is suitable for laser engraving processing on the surface of plastic products, optical devices and medical devices.

6. The color optimization method based on laser engraving technology according to claims 1-3, characterized in that: Laser engraving processing equipment includes: (1) Color matching module: used to dynamically adjust the concentration and ratio of toner 1 and toner 2 according to the Lab value offset; (2) Laser engraving processing module: used to control processing speed, frequency and power; (3) Color monitoring module: used to monitor the change of Lab value before and after engraving in real time, and calculate the color difference △E with porcelain white through Lab value; (4) Optimization feedback module: used to adjust laser engraving processing parameters based on the color difference value △E.

7. The color optimization method based on laser engraving technology according to claim 1, characterized in that: The color matching module and the color monitoring module operate in conjunction to achieve dynamic and real-time color adjustment feedback.

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