Thermal transfer printing inkjet ink composition and preparation method thereof
Through the combination of dye pigments, solvents, stabilizers and temperature-sensitive polymers, the problem of unstable dispersion of pigments at low temperatures and difficult pigments to transfer at high temperatures is solved, and efficient and stable inks suitable for thermal transfer inkjet technology are prepared.
Patent Information
- Application Number
- CN202410038607.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-10
- Publication Date
- 2025-07-11
AI Technical Summary
Traditional thermal transfer inkjet inks are unstable dispersion of pigments at low temperatures, and pigments are difficult to transfer and fix at high temperatures, resulting in poor printing quality and poor stability.
Inks that can stably disperse at low temperatures and effectively transfer and fix pigments at high temperatures are prepared by bead milling, microencapsulation and crosslinking reactions.
It realizes stable dispersion of ink at low temperatures and effective transfer and fixation of pigments at high temperatures, improves printing quality and durability, and is suitable for thermal transfer inkjet technology.
Smart Images
Figure BDA0004658979190000081 
Figure BDA0004658979190000101
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of thermal transfer inkjet inks, and specifically to a thermal transfer inkjet ink composition and a preparation method thereof. Background Art
[0002] Thermal transfer inkjet technology, as a common digital printing technology, is widely used in the field of pattern printing on materials such as textiles, ceramics, and metals.
[0003] Traditional inks are difficult to balance the stable dispersion and transfer fixation of pigments under both low-temperature and high-temperature conditions, which is mainly due to the formulation and characteristics of traditional inks. Specifically, traditional inks have the following problems:
[0004] 1. Stable dispersion of pigments at low temperature:
[0005] Under low-temperature conditions, the pigments in traditional inks often precipitate, agglomerate, or stratify, resulting in uneven ink color, unstable deposition, and even nozzle clogging, affecting the printing quality and stability. This is because the dispersants and stabilizers in traditional inks have limited effectiveness at low temperatures and cannot effectively maintain the stable dispersion of pigments.
[0006] 2. Transfer and fixation of pigments at high temperature:
[0007] Under high-temperature conditions, the pigments in traditional inks are often difficult to achieve rapid transfer and fixation. This is because the polymers and cross-linking agents in traditional inks may dissolve or denature at high temperatures, resulting in the inability of the pigments in the ink to effectively bind to fabrics or other materials, affecting the quality and durability of the printed patterns.
[0008] Therefore, traditional inks are difficult to balance the stable dispersion and transfer fixation of pigments under low-temperature and high-temperature conditions, which brings certain limitations to the application of thermal transfer inkjet technology. Summary of the Invention
[0009] Aiming at the deficiencies of the prior art, the present invention provides a thermal transfer inkjet ink composition and a preparation method thereof, aiming to maintain the stable dispersion of pigments at low temperature and contribute to the transfer and fixation of pigments at high temperature, thereby improving the applicability and printing quality of thermal transfer inkjet technology.
[0010] To achieve the above objectives, the present invention is realized through the following technical solutions: A thermal transfer inkjet ink composition, the ink composition comprising the following components:
[0011] Dye pigment: 10-15%;
[0012] Dye pigments are the color sources of inks. They can absorb light of specific wavelengths and reflect light of other wavelengths, thus presenting specific colors. In thermal transfer inkjet, the selection and formulation of dye pigments can affect the color saturation and clarity of the printed pattern.
[0013] Solvent: 75 - 80%;
[0014] The solvent plays a role in dissolving and diluting the dye pigments in the ink, enabling the ink to flow in the print head and dry quickly during printing.
[0015] Stabilizer and dispersant: 2 - 5%;
[0016] The role of the stabilizer and dispersant is to maintain the dispersed state of the pigments in the ink and prevent the pigments from precipitating or separating.
[0017] Poly(N - isopropylacrylamide): 2 - 4%;
[0018] Poly(N - isopropylacrylamide), abbreviated as PNIPAM, is a temperature - sensitive polymer. At low temperatures, it can help stabilize the dispersed state of the pigments in the ink and prevent precipitation or separation; while at high temperatures, due to its temperature - sensitive property, it can promote the transfer and fixation of the pigments, thus achieving thermal transfer.
[0019] Cross - linker: 0.5 - 1%;
[0020] The role of the cross - linker is to promote the cross - linking reaction between the polymers and pigments in the ink at high temperatures and enhance the fixation of the pigments on the fabric.
[0021] Preferably, the solvent is selected from ethyl acetate or acetone. The preferred ethyl acetate or acetone as the solvent is because of their volatility and dissolving power, which are beneficial to the ejection and drying of the ink.
[0022] Preferably, the stabilizer and dispersant are selected from polyvinylpyrrolidone. The preferred polyvinylpyrrolidone is selected because of its good dispersibility and stability, which can effectively maintain the uniform dispersion of the pigments.
[0023] Preferably, the cross - linker is a dialdehyde compound, and the dialdehyde compound is selected from glucose or formaldehyde. The preferred dialdehyde compounds, glucose or formaldehyde, are selected because they can effectively carry out cross - linking reactions and improve the wash resistance and durability of the ink.
[0024] Preferably, the ink further includes a pH regulator to adjust the pH value of the ink to the range of 6.5 - 7.5. An appropriate pH value helps maintain the stability of the ink and the printing quality.
[0025] The present invention also provides a preparation method for thermal transfer inkjet ink, including the following steps:
[0026] S1. Mix the pigment with a portion of the solvent and the dispersant, and perform bead milling at a temperature of 25 - 35°C for 2 - 4 h to achieve preliminary dispersion.
[0027] In this step, after the pigment is mixed with a portion of the solvent and the dispersant, bead milling is carried out to achieve preliminary dispersion of the pigment. Bead milling can refine and disperse the pigment particles in the solvent, enabling the pigment to be evenly dispersed in the ink, thereby improving the printing quality and stability of the ink.
[0028] S2. Disperse poly(N - isopropylacrylamide) in water and perform ultrasonic treatment for 5 - 10 min.
[0029] In this step, poly(N - isopropylacrylamide) is dispersed in water and ultrasonic treatment is carried out. Ultrasonic treatment can help the polymer to be better dispersed in the aqueous solution, improving its solubility and stability, and preparing for subsequent microencapsulation treatment.
[0030] S3. Slowly add the pre - dispersed pigment into the poly(N - isopropylacrylamide) solution, and use a homogenizer at a rate of 3000 - 5000 rpm for 10 - 20 min to carry out microencapsulation treatment.
[0031] In this step, the pre - dispersed pigment is slowly added into the poly(N - isopropylacrylamide) solution, and microencapsulation treatment is carried out using a homogenizer. The purpose of this step is to microencapsulate the pigment, that is, to wrap the pigment in polymer microcapsules to achieve stable dispersion of the pigment in the ink and subsequent heat - transfer fixation.
[0032] S4. Premix the cross - linker with a small amount of solvent and then add it to the microencapsulated pigment, and stir to promote the cross - linking reaction.
[0033] In this step, after the cross - linker is premixed with a small amount of solvent, it is added to the microencapsulated pigment, and stirring is carried out to promote the cross - linking reaction. The cross - linking reaction can cause cross - linking and binding between the polymer and the pigment in the ink, enhancing the fixing property and durability of the pigment on the fabric.
[0034] S5. Adjust the pH value of the ink.
[0035] Adjusting the pH value of the ink is to ensure that the ink is under suitable acidic or alkaline conditions, which is beneficial to the stability and printing quality of the ink.
[0036] S6. Filter the ink through a filter and perform defoaming treatment.
[0037] The last step is to filter the ink through a filter and perform degassing. Filtration can remove impurities and particles in the ink, improving the purity of the ink; degassing is to remove air bubbles in the ink to avoid the generation of air bubbles during the inkjet process, which may affect the printing effect.
[0038] Preferably, the stirring rate of the crosslinking reaction is 300 - 600 rpm, the temperature is maintained at 20 - 30 °C, and the reaction time is 30 - 60 minutes, which can ensure the full progress of the crosslinking reaction, enabling the polymers and pigments in the ink to effectively crosslink and bind.
[0039] Preferably, the pore size of the filter is 0.2 - 1.0 μm, which can effectively remove fine particles and impurities in the ink.
[0040] Preferably, the degassing time is 30 - 60 min, and this period can ensure that the air bubbles in the ink are fully removed, improving the stability of the ink.
[0041] The present invention provides a thermal transfer inkjet ink composition and its preparation method. It has the following beneficial effects:
[0042] 1. The thermal transfer inkjet ink prepared by the present invention has excellent thermal transfer effect and wash resistance in performance tests, meeting the high - standard requirements of thermal transfer printing, and can provide a new type of ink that is efficient, stable and practical for the thermal transfer industry.
[0043] 2. By adding PNIPAM, the present invention significantly improves the performance of the ink, enabling it to maintain the stable dispersion of pigments at low temperatures and promoting the effective transfer and fixation of pigments at high temperatures. These characteristics make the ink of the present invention very suitable for the thermal transfer inkjet printing process, capable of producing high - quality printing effects and meeting the requirements of industrial applications. Specific Embodiments
[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.
[0045] Example 1:
[0046] S1. Mix 15% carbon black pigment with 10% ethyl acetate and 3% polyvinylpyrrolidone.
[0047] S2. Grind the pigment mixture in a bead mill for 3 hours, with the temperature controlled at 30 °C.
[0048] S3. Disperse 3% of PNIPAM in deionized water, and then treat it with ultrasonic waves for 10 minutes at a power of 200 W.
[0049] S4. Slowly add the pre-dispersed pigment into the PNIPAM solution and carry out microencapsulation treatment using a high-speed homogenizer at a homogenization rate of 4000 rpm for 15 minutes.
[0050] S5. Premix 1% of formaldehyde and 5% of ethyl acetate and then add them to the microencapsulated pigment, stir at a rate of 500 rpm at a temperature of 25 °C for 45 minutes.
[0051] S6. Adjust the pH value of the ink to 7.0 and conduct a stability test.
[0052] S7. Filter the ink through a 0.5-μm precision filter and defoam for 45 minutes.
[0053] Example 2:
[0054] S1. Mix 12% of blue pigment with 15% of acetone and 4% of polyvinylpyrrolidone.
[0055] S2. Grind the pigment mixture in a bead mill for 2.5 hours with the temperature controlled at 28 °C.
[0056] S3. Disperse 2% of PNIPAM in deionized water, and then treat it with ultrasonic waves for 8 minutes at a power of 250 W.
[0057] S4. Slowly add the pre-dispersed pigment into the PNIPAM solution and carry out microencapsulation treatment using a high-speed homogenizer at a homogenization rate of 3500 rpm for 18 minutes.
[0058] S5. Premix 0.8% of glucose and 8% of acetone and then add them to the microencapsulated pigment, stir at a rate of 400 rpm at a temperature of 28 °C for 50 minutes.
[0059] S6. Adjust the pH value of the ink to 6.8 and conduct a stability test.
[0060] S7. Filter the ink through a 0.8-μm precision filter and defoam for 50 minutes.
[0061] Example 3:
[0062] S1. Mix 10% of red pigment with 20% of ethyl acetate and 2% of polyvinylpyrrolidone.
[0063] S2. Grind the pigment mixture in a bead mill for 4 hours with the temperature controlled at 35 °C.
[0064] S3. Disperse 4% of PNIPAM in deionized water, and then use ultrasonic treatment for 5 minutes at a power of 300 W.
[0065] S4. Slowly add the pre-dispersed pigment into the PNIPAM solution, and perform microencapsulation treatment using a high-speed homogenizer at a homogenization rate of 5000 rpm for 10 minutes.
[0066] S5. Premix 1% of formaldehyde and 10% of ethyl acetate and then add them to the microencapsulated pigment, with a stirring rate of 300 rpm, a temperature of 20 °C, and a reaction time of 60 minutes.
[0067] S6. Adjust the pH value of the ink to 7.5 and conduct a stability test.
[0068] S7. Filter the ink through a 1.0 μm precision filter and defoam for 30 minutes.
[0069] Example 4:
[0070] S1. Mix 14% of yellow pigment, 18% of ethyl acetate, and 5% of polyvinylpyrrolidone.
[0071] S2. Grind the pigment mixture in a bead mill for 3.5 hours with the temperature controlled at 32 °C.
[0072] S3. Disperse 3.5% of PNIPAM in deionized water, and then use ultrasonic treatment for 7 minutes at a power of 200 W.
[0073] S4. Slowly add the pre-dispersed pigment into the PNIPAM solution, and perform microencapsulation treatment using a high-speed homogenizer at a homogenization rate of 4500 rpm for 12 minutes.
[0074] S5. Premix 0.7% of glucose and 7% of ethyl acetate and then add them to the microencapsulated pigment, with a stirring rate of 450 rpm, a temperature of 22 °C, and a reaction time of 55 minutes.
[0075] S6. Adjust the pH value of the ink to 6.9 and conduct a stability test.
[0076] S7. Filter the ink through a 0.7 μm precision filter and defoam for 40 minutes.
[0077] Example 5:
[0078] S1. Mix 13% of cyan pigment, 17% of acetone, and 3.5% of polyvinylpyrrolidone.
[0079] S2. Grind the pigment mixture in a bead mill for 2 hours with the temperature controlled at 25 °C.
[0080] S3. Disperse 2.5% PNIPAM in deionized water, and then use ultrasonic treatment for 6 minutes at a power of 250 W.
[0081] S4. Slowly add the pre-dispersed pigment into the PNIPAM solution, and use a high-speed homogenizer for microencapsulation treatment at a homogenization rate of 4000 rpm for 20 minutes.
[0082] S5. Premix 0.9% formaldehyde and 9% acetone and then add them to the microencapsulated pigment, stir at a rate of 500 rpm, at a temperature of 30 °C, and the reaction time is 40 minutes.
[0083] S6. Adjust the pH value of the ink to 6.7 and conduct a stability test.
[0084] S7. Filter the ink through a 0.6 μm precision filter and defoam for 35 minutes.
[0085] Experimental example:
[0086] Purpose: To test the thermal transfer performance of the prepared ink.
[0087] 1. Select 100% polyester fabric as the transfer medium.
[0088] 2. Use a standard inkjet printhead for printing and print a preset pattern.
[0089] 3. Print the inks prepared in Examples 1-5 respectively.
[0090] 4. Place the printed fabric in a thermal transfer machine, and set the transfer conditions as 200 °C, a pressure of 5 bar, and a time of 30 seconds.
[0091] 5. After transfer, check the clarity and color saturation of the pattern.
[0092] 6. Conduct 10 washing tests on the transferred fabric using a washing machine, each washing for 45 minutes at a water temperature of 40 °C.
[0093] 7. After washing, check the clarity and color saturation of the pattern again to evaluate the wash resistance of the ink.
[0094] The test results are as follows:
[0095]
[0096] Based on the above experimental data, we can draw the following conclusions:
[0097] Thermal transfer effect evaluation: The inks of all examples showed high clarity and color saturation after thermal transfer. Among them, Example 3 had the best performance, with a transfer clarity of 99% and a color saturation of 96%. This indicates that the prepared inks can achieve effective pigment transfer at high temperatures and form distinct patterns on fabrics.
[0098] Wash resistance performance evaluation: After 10 washing tests, the inks of all examples still maintained high clarity and color saturation. Among them, the clarity and color saturation of Example 3 after washing were 92% and 90% respectively, showing the best wash resistance performance. This indicates that the ink has good water wash resistance characteristics, and the pattern is not easily blurred or the color fades due to washing.
[0099] Performance stability: In all examples, the performance of the ink showed a small decline during the transfer and washing processes, indicating that the prepared ink has good performance stability.
[0100] Highlight of advantages: Through the testing of the preparation method and examples of the thermal transfer inkjet ink composition, it can be seen that the prepared ink has a high transfer rate and good pattern clarity during thermal transfer. At the same time, it still maintains good color saturation and pattern clarity after washing, showing excellent wash resistance and durability. These characteristics make the ink very suitable for high-quality thermal transfer printing applications.
[0101] In summary, the thermal transfer inkjet ink prepared by this solution showed excellent thermal transfer effect and wash resistance performance in the performance test, meeting the high-standard requirements of thermal transfer printing. These results indicate that the ink composition and its preparation method are successful and can provide an efficient, stable and practical new ink for the thermal transfer industry.
[0102] Comparative example:
[0103] Purpose: To prove that using poly(N-isopropylacrylamide) can maintain the stable dispersion of pigments at low temperatures and contribute to the transfer and fixation of pigments at high temperatures.
[0104] Experimental method: Prepare ink samples: The inks prepared in Examples 1-5 of the present invention (containing PNIPAM), and control inks (not containing PNIPAM, with other components remaining the same and prepared using the same preparation method).
[0105] Low-temperature dispersibility test:
[0106] Place the two groups of ink samples in a low-temperature environment respectively, and observe and record the dispersion state of the pigments in the inks for a period of time.
[0107] High-temperature transfer and fixation test:
[0108] Use a standard inkjet printhead to spray two groups of inks onto transfer paper, printing the same preset pattern.
[0109] Place the printed transfer paper in a heat transfer machine, set the transfer conditions, and transfer the pattern onto a 100% polyester fabric.
[0110] Compare the pattern clarity and color saturation after transferring the two groups of inks.
[0111] Experimental data record:
[0112] Record the observation results of the low-temperature stability test (whether there is precipitation or stratification). Record the pattern clarity and color saturation after the high-temperature transfer and fixation test. The experimental data is as follows:
[0113]
[0114] Note:
[0115] Dispersion score: A qualitative score based on the experimental observation of the pigment dispersion state in the ink. 5 / 5 indicates no precipitation at all, and 1 / 5 indicates severe precipitation.
[0116] High-temperature transfer clarity: A score based on the edge clarity and detail retention of the pattern after transfer, expressed as a percentage.
[0117] High-temperature transfer color saturation: A score based on the color depth and vividness of the pattern after transfer, expressed as a percentage.
[0118] Observation results of low-temperature stability and high-temperature fixability: A descriptive summary of the performance of the ink under the test conditions.
[0119] Based on the above experimental data table, we can draw the following conclusions:
[0120] Low-temperature stability test:
[0121] All five embodiments of the ink of the present invention showed good pigment dispersion at a low temperature of 25°C. Among them, the dispersion scores of Embodiments 1, 2, and 3 reached the highest score (5 / 5), indicating that these formulations can well maintain the stable dispersion of pigments at low temperatures without precipitation or stratification.
[0122] Although there was a trace of precipitation in Embodiments 4 and 5, they still maintained good dispersion (4 / 5 score), indicating that these formulations also have a certain degree of low-temperature stability.
[0123] In contrast, the traditional ink showed poor performance in the low-temperature stability test, with a score of only 2 / 5, and obvious precipitation and stratification were observed, indicating poor pigment dispersion of the traditional ink at low temperatures.
[0124] High-temperature transfer and fixation test:
[0125] In the high-temperature transfer test at 200 °C, Example 3 of the ink of the present invention showed the best performance, with a transfer clarity of 99% and a color saturation of 96%, demonstrating extremely high pattern clarity and color saturation.
[0126] The transfer clarity and color saturation of the other examples (1, 2, 4, and 5) were also relatively high, all above 90%, indicating that the ink with the intelligent additive can effectively transfer the pigment to the fabric at high temperature and has a good fixation effect.
[0127] The performance of the traditional ink in the high-temperature transfer and fixation test was significantly inferior to that of the ink of the present invention. The transfer clarity and color saturation were both lower than 80%, the pattern was unclear, and the color was distorted, indicating that the transfer and fixation effect of the pigment was poor without the intelligent additive.
[0128] The five examples of the ink of the present invention were all significantly superior to the traditional ink in terms of low-temperature stability and high-temperature transfer and fixation. This proves that the addition of PNIPAM in the ink of the present invention significantly improves the performance of the ink, enabling it to maintain the stable dispersion of the pigment at low temperature and promoting the effective transfer and fixation of the pigment at high temperature. These characteristics make the ink of the present invention very suitable for the thermal transfer inkjet printing process, capable of producing high-quality printing effects and meeting the requirements of industrial applications.
[0129] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A thermal transfer inkjet ink composition, characterized in that, The ink composition comprises the following components: Dye pigment: 10 - 15%; Solvent: 75 - 80%; Stabilizer and dispersant: 2 - 5%; Poly(N-isopropylacrylamide): 2 - 4%; Crosslinking agent: 0.5 - 1%.
2. The thermal transfer inkjet ink composition according to claim 1, characterized in that, The solvent is selected from ethyl acetate or acetone.
3. The thermal transfer inkjet ink composition according to claim 1, wherein The stabilizer and dispersant are selected from polyvinylpyrrolidone.
4. The thermal transfer inkjet ink composition according to claim 1, characterized in that, The crosslinking agent is a dialdehyde compound.
5. The thermal transfer inkjet ink composition according to claim 4, wherein The dialdehyde compound is selected from glucose or formaldehyde.
6. The thermal transfer inkjet ink composition according to claim 1, wherein The ink further comprises a pH regulator to adjust the pH value of the ink to the range of 6.5 - 7.
5.
7. A method for preparing a thermal transfer inkjet ink for preparing a thermal transfer inkjet ink composition according to any one of claims 1-6, characterized in that, Comprising the following steps: S1. Mix the pigment with a part of the solvent and the dispersant, and carry out bead milling at a temperature of 25 - 35°C for 2 - 4 h to achieve preliminary dispersion; S2. Disperse poly(N-isopropylacrylamide) in water and carry out ultrasonic treatment for 5 - 10 min; S3. Slowly add the pre-dispersed pigment into the poly(N-isopropylacrylamide) solution, and use a homogenizer at a rate of 3000 - 5000 rpm for 10 - 20 min for microencapsulation treatment; S4. Premix the crosslinking agent with a small amount of solvent and then add it to the microencapsulated pigment, and stir to promote the crosslinking reaction; S5. Adjust the pH value of the ink; S6. Filter the ink through a filter and carry out degassing treatment.
8. The preparation method of the thermal transfer inkjet ink according to claim 7, characterized in that, The stirring rate of the crosslinking reaction is 300 - 600 rpm, the temperature is maintained at 20 - 30°C, and the reaction time is 30 - 60 minutes.
9. The preparation method of the thermal transfer inkjet ink according to claim 7, characterized in that, The pore size of the filter is 0.2 - 1.0 μm.
10. The preparation method of the thermal transfer inkjet ink according to claim 7, wherein The time of the degassing treatment is 30 - 60 min.