Coating wet sizing digital printing paste composition for Single Pass digital printing machine and preparation method of coating wet sizing digital printing paste composition

Abstract

The invention relates to a coating wet sizing digital printing paste composition for a Single Pass digital printing machine, which comprises cationic starch with the degree of substitution (DS) greater than or equal to 0.10; a HEUR thickener; a wetting agent; a water-based polycarbodiimide cross-linking agent; a pH buffer; a nano silicon dioxide functional additive; and a preservative. The invention relates to a preparation method of a coating wet sizing digital printing paste composition for a Single Pass digital printing machine, which comprises the following steps: uniformly mixing cationic starch of which the substitution degree DS is greater than or equal to 0.10, an HEUR thickener, a wetting agent, a water-based polycarbodiimide cross-linking agent, a pH buffer agent, a nano silicon dioxide functional additive and a preservative, the defects of the existing digital printing paste in key performance indexes such as color yield, crockfastness and definition are remarkably improved, so that the overall quality of a printed product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of textile printing materials, and particularly relates to a coating wet sizing digital printing paste composition for a Single Pass digital printer and a preparation method thereof. Background Art

[0002] With the continuous development of digital printing technology, the Single Pass digital printer has occupied an increasingly important position in the textile printing and dyeing industry with its high-efficiency and high-speed printing capabilities; however, there are many problems in the actual application of digital printing pastes adapted to the Single Pass digital printer.

[0003] Common problems include unsatisfactory printing color yield, resulting in insufficiently bright and saturated printing colors; poor rubbing fastness, making the printed pattern prone to color fading during daily use and washing; insufficient printing clarity, making it difficult to accurately present complex and delicate pattern details; these problems seriously restrict the quality improvement and market expansion of printed products; therefore, it is urgent to develop a high-performance digital printing paste that can overcome the above defects and is suitable for the Single Pass digital printer. Summary of the Invention

[0004] The present invention aims to provide a coating wet sizing digital printing paste composition for a Single Pass digital printer and a preparation method thereof, so as to significantly improve the deficiencies of existing digital printing pastes in key performance indicators such as color yield, rubbing fastness, and clarity, thereby enhancing the overall quality of printed products.

[0005] To solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A coating wet sizing digital printing paste composition for a Single Pass digital printer, comprising:

[0007] Cationic starch with a degree of substitution DS≥0.10, and its weight percentage in the composition is 84.65%-94.55%;

[0008] HEUR thickener, and its weight percentage in the composition is 3%-8%;

[0009] Wetting agent, and its weight percentage in the composition is 0.3%-1.2%;

[0010] Aqueous polycarbodiimide crosslinking agent, and its weight percentage in the composition is 1.5%-4%;

[0011] pH buffer, and its weight percentage in the composition is 0.5%-1.5%;

[0012] Nano-silica functional additive, with a weight percentage of 0.1%-0.5% of the composition;

[0013] Preservative, with a weight percentage of 0.05%-0.15% of the composition.

[0014] The synthesis process of the cationic starch includes the following steps:

[0015] S1, alkalization: Disperse cassava starch in a 40% ethanol aqueous solution with a solid-liquid ratio of 1:4, add tetramethylammonium hydroxide to adjust the pH to 11.5, and activate at 50°C for 1 hour to obtain starch glucose units;

[0016] S2, etherification: Add the starch glucose units to 2,3-epoxypropyltrimethylammonium chloride in a ratio of n(2,3-epoxypropyltrimethylammonium chloride):n(starch glucose units)=0.12:1, and react at 55°C for 6 hours;

[0017] S3, termination: Adjust the pH of the etherified solution to 6.8 with glacial acetic acid, and add ethanol for precipitation;

[0018] S4, purification: Use an ultrafiltration membrane with a molecular weight cut-off of 10 kDa to remove by-products, and spray dry to obtain cationic starch with DS≥0.10.

[0019] The amylose content of the cassava starch in step S1 is ≤20%.

[0020] The purity of 2,3-epoxypropyltrimethylammonium chloride in step S2 is ≥99%.

[0021] The wetting agent is an alkynediol compound, and the dynamic surface tension is ≤28 mN / m.

[0022] The pH buffer is a triethanolamine-citric acid composite system.

[0023] The preservative is benzisothiazolinone.

[0024] A preparation method of a coating wet-sizing digital printing paste composition for a Single Pass digital printing machine, comprising the following steps: mixing a cationic starch with a degree of substitution DS≥0.10, a HEUR thickener, a wetting agent, an aqueous polycarbodiimide crosslinking agent, a pH buffer, a nano-silica functional aid, and a preservative evenly; wherein the cationic starch accounts for 84.65%-94.55% by weight of the composition, the HEUR thickener accounts for 3%-8% by weight of the composition, the wetting agent accounts for 0.3%-1.2% by weight of the composition, the aqueous polycarbodiimide crosslinking agent accounts for 1.5%-4% by weight of the composition, the pH buffer accounts for 0.5%-1.5% by weight of the composition, the nano-silica functional aid accounts for 0.1%-0.5% by weight of the composition, and the preservative accounts for 0.05%-0.15% by weight of the composition.

[0025] The wetting agent is an alkynediol compound with a dynamic surface tension ≤28 mN / m; the pH buffer is a triethanolamine-citric acid composite system; the preservative is benzisothiazolinone.

[0026] The technical effects that can be achieved by the present invention are:

[0027] 1. Color yield: In the present invention, the cationic starch has DS≥0.12, the electrostatic adsorption coating efficiency is improved, and it has a high color yield;

[0028] 2. Clarity: The HEUR thickener endows the paste with the "shear thinning" property (the viscosity drops to 200 mPa·s at a shear rate of 1000 s-1), which is suitable for the high-frequency spraying of the Single Pass nozzle and has higher clarity;

[0029] 3. Dry / wet rubbing fastness: The polycarbodiimide crosslinking agent and nano-SiO2 act synergistically to have higher dry / wet rubbing fastness;

[0030] 4. Process: The present invention has no PVA component, the wastewater COD emission is reduced, and it meets the requirements of the Eco-Passport certification. Detailed implementation mode

[0031] The present invention will be further elaborated in detail below.

[0032] A coating wet-sizing digital printing paste composition for a Single Pass digital printing machine, comprising:

[0033] Cationic starch with a degree of substitution DS≥0.10, which accounts for 84.65%-94.55% by weight of the composition;

[0034] HEUR thickener, which accounts for 3%-8% by weight of the composition;

[0035] A wetting agent, with a weight percentage of 0.3% - 1.2% of the composition;

[0036] An aqueous polycarbodiimide crosslinking agent, with a weight percentage of 1.5% - 4% of the composition;

[0037] A pH buffer, with a weight percentage of 0.5% - 1.5% of the composition;

[0038] A nano-silica functional additive, with a weight percentage of 0.1% - 0.5% of the composition;

[0039] A preservative, with a weight percentage of 0.05% - 0.15% of the composition.

[0040] The synthesis process of the above cationic starch includes the following steps:

[0041] S1, alkalization: Disperse cassava starch in a 40% ethanol aqueous solution with a solid-liquid ratio of 1:4, add tetramethylammonium hydroxide to adjust the pH to 11.5, and activate at 50°C for 1 hour to obtain starch glucose units;

[0042] S2, etherification: Add the starch glucose units to 2,3-epoxypropyltrimethylammonium chloride at a ratio of n(2,3-epoxypropyltrimethylammonium chloride):n(starch glucose units) = 0.12:1, and react at 55°C for 6 hours;

[0043] S3, termination: Adjust the pH of the etherified solution to 6.8 with glacial acetic acid, and add ethanol for precipitation;

[0044] S4, purification: Use an ultrafiltration membrane with a cut-off molecular weight of 10 kDa to remove by-products, and spray-dry to obtain cationic starch with DS≥0.10.

[0045] In the above S1 step, the amylose content of cassava starch ≤20%; in the S2 step, the purity of 2,3-epoxypropyltrimethylammonium chloride ≥99%; the wetting agent is an alkynediol compound with a dynamic surface tension ≤28 mN / m; the pH buffer is a triethanolamine-citric acid composite system; the preservative is benzisothiazolinone.

[0046] A preparation method of a coating wet sizing digital printing paste composition for a Single Pass digital printing machine, comprising the following steps: mixing a cationic starch with a degree of substitution DS≥0.10, a HEUR thickener, a wetting agent, an aqueous polycarbodiimide crosslinking agent, a pH buffer, a nano-silica functional aid, and a preservative evenly; wherein the cationic starch accounts for 84.65%-94.55% by weight of the composition, the HEUR thickener accounts for 3%-8% by weight of the composition, the wetting agent accounts for 0.3%-1.2% by weight of the composition, the aqueous polycarbodiimide crosslinking agent accounts for 1.5%-4% by weight of the composition, the pH buffer accounts for 0.5%-1.5% by weight of the composition, the nano-silica functional aid accounts for 0.1%-0.5% by weight of the composition, and the preservative accounts for 0.05%-0.15% by weight of the composition; specifically, the wetting agent is an alkynediol compound with a dynamic surface tension ≤28 mN / m; the pH buffer is a triethanolamine-citric acid composite system, and the preservative is benzisothiazolinone.

[0047] Example 1

[0048] Ratio of the paste composition:

[0049] Cationic starch (DS = 0.12): 84.65%

[0050] HEUR thickener (i.e., hydrophobic modified polyurethane thickener): 8%

[0051] Alkynediol compound (wetting agent): 1.2%

[0052] Aqueous polycarbodiimide crosslinking agent: 4%

[0053] Triethanolamine-citric acid composite system (PH buffer): 1.5%

[0054] Nano-silica functional aid: 0.5%

[0055] Benzisothiazolinone (preservative): 0.15%

[0056] Application performance test (refer to GB / T 3920-2008, ISO 105-E04):

[0057]

[0058] Advantages (comparison between the present invention and market competitors):

[0059] It can be seen from the above data that the dry and wet rubbing fastness of Example 1 is the best. In addition, it can effectively improve the color and clarity of the printed products and reduce the COD emission.

[0060] Example 2

[0061] Ratio of the slurry composition:

[0062] Cationic starch (DS = 0.15): 94.55%

[0063] HEUR thickener (i.e., hydrophobically modified polyurethane thickener): 3%

[0064] Alkynediol compound (wetting agent): 0.3%

[0065] Aqueous polycarbodiimide crosslinking agent: 1.5%

[0066] Triethanolamine-citric acid composite system (PH buffer): 0.5%

[0067] Nano-silica functional additive: 0.1%

[0068] Benzisothiazolinone (preservative): 0.05%

[0069] Application performance test (refer to GB / T 3920-2008, ISO 105-E04):

[0070]

[0071] Advantages (comparison between the present invention and market competitors):

[0072] It can be seen from the above data that the color of Example 2 is the best. In addition, it can effectively improve the dry and wet rubbing fastness and clarity of the printed products, and reduce the COD emission.

[0073] Example 3

[0074] Ratio of the slurry composition:

[0075] Cationic starch (DS = 0.1): 88.5%

[0076] HEUR thickener (i.e., hydrophobically modified polyurethane thickener): 6%

[0077] Alkynediol compound (wetting agent): 1%

[0078] Aqueous polycarbodiimide crosslinking agent: 3%

[0079] Triethanolamine-citric acid composite system (PH buffer): 1%

[0080] Nano-silica functional additive: 0.4%

[0081] Benzisothiazolinone (preservative): 0.1%

[0082] Application performance test (refer to GB / T 3920-2008, ISO 105-E04):

[0083]

[0084] Advantages (comparison between the present invention and market competitors):

[0085] From the above data, it can be seen that the performance of Example 3 is the best comprehensively, which can effectively improve the color yield, dry and wet rubbing fastness, and clarity of printed products, and reduce COD emissions.

[0086] From the above three examples, it can be seen that in the application performance test of the slurry composition of the present invention, the K / S value is ≥13 (the existing market competitors are 9.8), the dry rubbing fastness is ≥4 levels (the existing market competitors are 3 levels), the wet rubbing fastness is between 3-4 levels (the existing market competitors are 2-3 levels), the bleeding value is ≤0.5 mm (the existing market competitors are 0.9 mm), and the COD emission is ≤2500 mg / L (the existing market competitors are 6500 mg / L). Obviously, the present invention significantly improves the deficiencies of the existing digital printing slurries in key performance indicators such as color yield, rubbing fastness, and clarity, thereby improving the overall quality of printed products and reducing COD emissions.

Claims

1. A coating wet sizing digital printing paste composition for a Single Pass digital printing machine, characterized in that, Comprising: Cationic starch with a degree of substitution DS≥0.10, accounting for 84.65%-94.55% by weight of the composition; HEUR thickener, accounting for 3%-8% by weight of the composition; Wetting agent, accounting for 0.3%-1.2% by weight of the composition; Aqueous polycarbodiimide crosslinking agent, accounting for 1.5%-4% by weight of the composition; pH buffer, accounting for 0.5%-1.5% by weight of the composition; Nano-silica functional aid, accounting for 0.1%-0.5% by weight of the composition; Preservative, accounting for 0.05%-0.15% by weight of the composition.

2. The coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, wherein The synthesis process of the cationic starch Comprises the following steps: S1, alkalization: Dispersing tapioca starch in a 40% ethanol aqueous solution with a solid-liquid ratio of 1:4, adding tetramethylammonium hydroxide to adjust the pH to 11.5, and activating at 50°C for 1 hour to obtain starch glucose units; S2, etherification: Adding the starch glucose units to 2,3-epoxypropyltrimethylammonium chloride in a ratio of n(2,3-epoxypropyltrimethylammonium chloride):n(starch glucose units)=0.12:1, and reacting at 55°C for 6 hours; S3, termination: Adjusting the pH of the etherified solution to 6.8 with glacial acetic acid, and adding ethanol for precipitation; S4， Purification: Using an ultrafiltration membrane with a molecular weight cut-off of 10 kDa to remove by-products, and spray-drying to obtain cationic starch with DS≥0.

10.

3. The coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 2, wherein: The amylose content of the tapioca starch in step S1 is ≤20%.

4. The coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 2, characterized in that: The purity of 2,3-epoxypropyltrimethylammonium chloride in step S2 is ≥99%.

5. A coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The wetting agent is an alkynediol compound with a dynamic surface tension ≤28 mN / m.

6. A coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The pH buffer is a triethanolamine-citric acid composite system.

7. A coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The preservative is benzisothiazolinone.

8. A preparation method of a coating wet sizing digital printing paste composition for a Single Pass digital printing machine, characterized in that, Comprises the following steps: Mixing evenly the cationic starch with a degree of substitution DS≥0.10, HEUR thickener, wetting agent, aqueous polycarbodiimide crosslinking agent, pH buffer, nano-silica functional aid, and preservative; wherein the cationic starch accounts for 84.65%-94.55% by weight of the composition, the HEUR thickener accounts for 3%-8% by weight of the composition, the wetting agent accounts for 0.3%-1.2% by weight of the composition, the aqueous polycarbodiimide crosslinking agent accounts for 1.5%-4% by weight of the composition, the pH buffer accounts for 0.5%-1.5% by weight of the composition, the nano-silica functional aid accounts for 0.1%-0.5% by weight of the composition, and the preservative accounts for 0.05%-0.15% by weight of the composition.

9. The preparation method of a coating wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 8, characterized in that: The wetting agent is an alkynediol compound with a dynamic surface tension ≤28 mN / m; the pH buffer is a triethanolamine-citric acid composite system; the preservative is benzisothiazolinone.

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