Strong-alkali-resistant washing color ink as well as preparation method and application thereof

Abstract

The invention relates to washing color ink with strong alkali resistance as well as a preparation method and application of the washing color ink. The washing color ink comprises the following components in parts by mass: 10-20 parts of pigment; 10 to 20 parts of water-based acrylic resin; 30 to 40 parts of a modified polyurethane mixed emulsion; 30 to 40 parts of a solvent; 2-5 parts of an auxiliary agent; wherein the modified polyurethane mixed emulsion is a mixed solution of polyol, isocyanate and a hydrophilic chain extender; the solvent is a mixed solution of absolute ethyl alcohol and water; the auxiliary agent comprises the following secondary components in parts by mass: 0.3-1.5 parts of a defoaming agent; 0.3-2 parts of a leveling agent; 0.5-3 parts of a dispersant; and 0.2 to 1.5 parts of a surfactant. Compared with the prior art, the alkali-resistant pigment and the modified polyurethane mixed emulsion are selected as the main body of the washing color ink, so that the alkali water resistance of the washing color ink can be effectively improved.

Description

Technical Field

[0001] The invention relates to the field of printing ink, in particular to a water-washable color ink with strong alkali resistance and a preparation method and application thereof. Background Art

[0002] The chemical properties of printing ink mainly refer to the resistance of the ink layer to chemical substances during the printing process or after printing. The physical and chemical properties of ink mainly refer to its density, fineness, transparency, glossiness, light resistance, heat resistance, and resistance to acid, alkali, water, and solvent (alcohol).

[0003] The ability of ink to resist water infiltration is called water resistance. The water resistance of ink mainly depends on the stability of the ink structure, which in turn depends on the combination of the pigment and the binder used and the water resistance of the pigment. The ability of ink to resist alkaline substances is called the alkali resistance of ink. The alkali resistance of ink is mainly determined by the alkali resistance of the pigment and the binder used. During the printing process, the ink is affected by various alkaline substances. If the alkali resistance of the ink itself is insufficient, the alkaline environment may even destroy the structure of the ink and decompose the pigment and the binder.

[0004] The general printing environment does not have high requirements for the alkali resistance of inks. Appropriate alkali resistance can meet the requirements. However, for some products used in strong alkaline environments or printing processes that cannot avoid strong alkalis, the requirements for the alkali resistance of printing inks will become very high. For water-based inks, excellent alkali resistance is even more difficult. Therefore, it is urgent to overcome this difficulty. Summary of the invention

[0005] The purpose of the present invention is to provide a water-washable color ink with strong alkali resistance and a preparation method and application thereof in order to overcome the defects of the existing water-based ink such as poor alkaline water resistance.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a water-washable color ink with strong alkali resistance, comprising the following components in parts by weight:

[0008] Pigment 10-20 parts;

[0009] 10-20 parts of water-based acrylic resin;

[0010] 30-40 parts of modified polyurethane mixed emulsion;

[0011] 30-40 parts of solvent;

[0012] 2-5 parts of additives;

[0013] Wherein, the modified polyurethane mixed emulsion is a mixed solution of polyol, isocyanate and hydrophilic chain extender;

[0014] The solvent is a mixture of anhydrous ethanol and water;

[0015] The auxiliary agent includes the following subcomponents in parts by weight:

[0016] Defoaming agent 0.3-1.5 parts;

[0017] Leveling agent 0.3-2 parts;

[0018] Dispersant 0.5-3 parts;

[0019] Surfactant 0.2-1.5 parts;

[0020] The water-based acrylic resin is mainly used as a pigment binder, and the modified polyurethane mixed emulsion has very excellent water resistance and alkali resistance.

[0021] In some embodiments, the pigment is an alkali-resistant pigment.

[0022] In some specific embodiments, the mass ratio of polyol, isocyanate and hydrophilic chain extender in the modified polyurethane mixed emulsion is 1:1:1.

[0023] The polyol is selected from any one or more of polyether polyol, neopentyl glycol, 1,2-propylene glycol and ethylene glycol, which can significantly improve the water resistance and alkali resistance of the synthetic resin.

[0024] The hydrophilic chain extender is dicarboxymethyl propionic acid, which has a neopentyl glycol structure and can impart certain heat resistance and hydrolysis resistance to the product.

[0025] The preparation method of the modified polyurethane mixed emulsion is:

[0026] Under nitrogen protection, place the polyol in a reaction container, heat to about 50°C, keep warm for 20-30 minutes, add isocyanate, raise the temperature to 60-70°C, react for 4-5 hours, finally add a hydrophilic chain extender, raise the temperature to 75°C, react for about 0.5 hours, cool and dilute to obtain a modified polyurethane mixed emulsion.

[0027] In some specific embodiments, the mass ratio of anhydrous ethanol to water in the solvent is 4:1.

[0028] In some specific embodiments, the defoaming agent is polydimethylsiloxane, the dispersant is oleic acid amide, the leveling agent is modified acrylic acid, and the surfactant is disodium dodecylbenzene sulfonate.

[0029] The second technical solution of the present invention is to provide a method for preparing a water-washable color ink having strong alkaline resistance as described in one of the above technical solutions, comprising the following steps:

[0030] S1. Pigment dissolution: mixing and filtering the pigment and solvent to obtain a color paste with low fineness;

[0031] S2, mixing and grinding the color paste, water-based acrylic resin, surfactant, defoamer and leveling agent obtained in step S1 to obtain a semi-finished color ink;

[0032] S3, adding a dispersant and a modified polyurethane mixed emulsion to the semi-finished ink obtained in step S2, and then adding a pH adjuster to adjust the pH value to alkaline, stirring and filtering, to obtain a washable ink with strong alkaline resistance.

[0033] In some specific embodiments, in step S1, the mesh number of the sieve is 200 meshes.

[0034] In some specific embodiments, in step S2, the powder is ground to a fineness of less than 5 μm.

[0035] In some specific embodiments, in step S3, the pH is adjusted to 8-9.

[0036] The pH adjuster is preferably an aqueous ammonia solution having a concentration of 5% g / mL.

[0037] The third technical solution of the present invention is to provide an application of a water-washable ink having strong alkali resistance as described in one of the above technical solutions, wherein the water-washable ink is used for printing on film substrates and non-absorbent substrates.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] In the present invention, alkali-resistant pigment and modified polyurethane mixed emulsion are selected as the main body of the water-washable ink, which can effectively improve the alkali water resistance of the water-washable ink. When printed on a film substrate and soaked in high-concentration alkaline water, the water-washable ink will not fall off significantly. In addition, the modified polyurethane mixed emulsion has excellent adhesion and good fastness on non-absorbent substrates. By using a surfactant to adjust the tension between the pigment, the solvent and the resin, the tension of each component in the water-washable ink is matched, and a water-washable ink with excellent printing performance is obtained. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0041] In the following examples and comparative examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0042] Alkali-resistant pigments: Huber Ink (Shenzhen) Co., Ltd. (Huber)

[0043] Water-based acrylic resin: Huber Ink (Shenzhen) Co., Ltd. (Huber)

[0044] Dicarboxymethylpropionic acid: BYK Additives (Shanghai) Co., Ltd. (BYK)

[0045] Modified acrylic acid: BYK Additives (Shanghai) Co., Ltd. (BYK)

[0046] Disodium dodecylbenzenesulfonate: BYK Additives (Shanghai) Co., Ltd. (BYK)

[0047] Embodiment 1:

[0048] A water-washable color ink with strong alkali resistance is prepared by the following components in parts by mass:

[0049] 15 parts of alkali-resistant pigment;

[0050] 15 parts of water-based acrylic resin;

[0051] 35 parts of modified polyurethane mixed emulsion;

[0052] 32 parts of solvent;

[0053] 3 parts of additives.

[0054] in,

[0055] The preparation method of the modified polyurethane mixed emulsion is as follows: under nitrogen protection, polyether polyol, neopentyl glycol, 1,2-propylene glycol and ethylene glycol are mixed in a mass ratio of 1:1:1:1 and then placed in a reaction container, heated to about 50°C, kept warm for 25 minutes, isocyanate is added in a mass ratio of 1:1 between polyol and isocyanate, the temperature is raised to 65°C, the reaction is carried out for about 4.5 hours, and finally, a hydrophilic chain extender dicarboxymethyl propionic acid is added in a mass ratio of the same proportion (that is, the mass ratio of polyol, isocyanate and dicarboxymethyl propionic acid is 1:1:1), the temperature is raised to 75°C, the reaction is carried out for about 0.5 hours, the temperature is lowered and diluted, and the modified polyurethane mixed emulsion can be obtained.

[0056] The solvent is a mixed solution of anhydrous ethanol and water in a mass ratio of 4:1.

[0057] The additive is composed of the following subcomponents in parts by mass: 0.5 parts of polydimethylsiloxane defoamer, 0.5 parts of modified acrylic leveling agent, 1 part of oleic acid amide dispersant, 0.5 parts of disodium dodecylbenzene sulfonate surfactant, and pH adjuster is added in appropriate amount according to site requirements.

[0058] The method for preparing the above-mentioned water-washable color ink having strong alkaline resistance comprises the following steps:

[0059] (1) Pigment dissolution: alkaline pigment and solvent are uniformly mixed in a mass ratio of 3:5, stirred at high speed for about 1 h at room temperature, at a speed of 1200 rpm, to obtain a dissolved color paste, which is filtered through a 200-mesh filter to obtain a color paste with lower fineness;

[0060] (2) Pre-dispersion of ingredients: The color paste obtained in step (1) is mixed with a water-based acrylic resin, and stirred at high speed at a speed of 1200 rpm. Then, disodium dodecylbenzene sulfonate surfactant, polydimethylsiloxane defoamer and modified acrylic acid leveling agent are added. After mixing evenly, the mixture is ground to a fineness of <5 μm to obtain a semi-finished color ink.

[0061] (3) The semi-finished ink is further processed by adding oleic acid amide dispersant to the semi-finished ink obtained in step (2) for dispersion, then adding modified polyurethane mixed emulsion, mixing evenly, adding pH adjuster to adjust pH value to about 8.5, stirring and dispersing, filtering, and obtaining a water-washable ink having strong alkali resistance.

[0062] The prepared washable ink was tested for its alkaline water resistance: at room temperature, the alkaline solution was 10% NaOH solution, and the ink was treated in a water bath at a temperature of about 30°C. The ink was applied to the desired substrate using a coater or RK machine, and the sample was completely immersed in the alkaline solution. After soaking for a period of time, the sample was taken out of the alkaline solution, and then rinsed with clean water to observe the bonding degree between the ink and the substrate. The results are shown in Table 1.

[0063] The prepared color ink was coated on a film and tested for fastness using 3M tape. The results showed that the adhesion was very good and the adhesion fastness could reach 90%.

[0064] Table 1 Performance of water-washable ink in Example 1

[0065]

[0066] Comparative Example 1:

[0067] Compared with Example 1, most of them are the same, except that the modified polyurethane mixed emulsion is replaced with a water-based acrylic resin of the same mass.

[0068] The water-washable ink is prepared from the following components in parts by mass:

[0069] 15 parts of alkali-resistant pigment;

[0070] 50 parts of water-based acrylic resin;

[0071] 32 parts of solvent;

[0072] 3 parts of additives.

[0073] The solvent is a mixed solution of anhydrous ethanol and water in a mass ratio of 4:1.

[0074] The additive is composed of the following subcomponents in parts by mass: 0.5 parts of polydimethylsiloxane defoamer, 0.5 parts of modified acrylic leveling agent, 1 part of oleic acid amide dispersant, 0.5 parts of disodium dodecylbenzene sulfonate surfactant, and pH adjuster is added in appropriate amount according to site requirements.

[0075] The method for preparing the water-washable ink comprises the following steps:

[0076] (1) Pigment dissolution: alkaline pigment and solvent are uniformly mixed in a mass ratio of 3:5, stirred at high speed for about 1 h at room temperature, at a speed of 1200 rpm, to obtain a dissolved color paste, which is filtered through a 200-mesh filter to obtain a color paste with lower fineness;

[0077] (2) Pre-dispersion of ingredients: The color paste obtained in step (1) is mixed with a water-based acrylic resin, and stirred at high speed at a speed of 1200 rpm. Then, disodium dodecylbenzene sulfonate surfactant, polydimethylsiloxane defoamer and modified acrylic acid leveling agent are added. After mixing evenly, the mixture is ground to a fineness of <5 μm to obtain a semi-finished color ink.

[0078] (3) Reprocessing the semi-finished ink: add oleic acid amide dispersant to the semi-finished ink obtained in step (2) for dispersion, then add a pH adjuster to adjust the pH value to about 8, stir and disperse, and filter to obtain a water-washable ink.

[0079] The prepared water-washable ink was coated on a film and tested for fastness using 3M tape. The adhesion was poor, and the adhesion fastness was far below 60%, which could not meet the requirements.

[0080] The results of alkali resistance are shown in Table 2:

[0081] Table 2 Performance of water-washable ink of comparative example 1

[0082]

[0083] It shows that modified polyurethane mixed emulsion can effectively improve the alkali resistance and adhesion fastness of water-washable ink.

[0084] Comparative Example 2:

[0085] Compared with Example 1, most of them are the same, except that the hydrophilic chain extender component in the modified polyurethane mixed emulsion is changed. The hydrophilic chain extender component in the modified polyurethane mixed emulsion is increased to 50%.

[0086] The prepared water-washable ink was coated on a film and tested for fastness using 3M tape. The adhesion was acceptable, with the adhesion fastness being between 80% and 90%.

[0087] Its water resistance and alkali resistance are poor. The alkali resistance results are shown in Table 3:

[0088] Table 3 Performance of water-washable ink in comparative example 2

[0089]

[0090] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A water-washable ink having strong alkaline resistance, characterized in that: The composition includes the following components in parts by weight: Pigment 10-20 parts; 10-20 parts of water-based acrylic resin; 30-40 parts of modified polyurethane mixed emulsion; 30-40 parts of solvent; 2-5 parts of additives; Wherein, the modified polyurethane mixed emulsion is a mixed solution of polyol, isocyanate and hydrophilic chain extender; The solvent is a mixture of anhydrous ethanol and water; The auxiliary agent includes the following subcomponents in parts by weight: Defoaming agent 0.3-1.5 parts; Leveling agent 0.3-2 parts; Dispersant 0.5-3 parts; Surfactant 0.2-1.5 parts.

2. The water-washable ink with strong alkaline resistance according to claim 1, characterized in that: The pigment is an alkali-resistant pigment.

3. The water-washable ink with strong alkaline resistance according to claim 1, characterized in that: The mass ratio of polyol, isocyanate and hydrophilic chain extender in the modified polyurethane mixed emulsion is 1:1:

1. The polyol is selected from any one or more of polyether polyol, neopentyl glycol, 1,2-propylene glycol and ethylene glycol, and the hydrophilic chain extender is dicarboxymethyl propionic acid.

4. The water-washable ink with strong alkaline resistance according to claim 1, characterized in that: The mass ratio of anhydrous ethanol to water in the solvent is 4:

1.

5. The water-washable ink with strong alkaline resistance according to claim 1, characterized in that: The defoaming agent is polydimethylsiloxane, the dispersant is oleic acid amide, the leveling agent is modified acrylic acid, and the surfactant is disodium dodecylbenzene sulfonate.

6. A method for preparing a water-washable ink having strong alkaline resistance as claimed in any one of claims 1 to 5, characterized in that: The steps include: S1. Pigment dissolution: mixing and filtering the pigment and solvent to obtain a color paste with low fineness; S2, mixing and grinding the color paste, water-based acrylic resin, surfactant, defoamer and leveling agent obtained in step S1 to obtain a semi-finished color ink; S3, adding a dispersant and a modified polyurethane mixed emulsion to the semi-finished ink obtained in step S2, and then adding a pH adjuster to adjust the pH value to alkaline, stirring and filtering, to obtain a washable ink with strong alkaline resistance.

7. The method for preparing a water-washable ink having strong alkaline resistance according to claim 6, characterized in that: In step S1, the mesh number of the sieve is 200 meshes.

8. The method for preparing a water-washable ink having strong alkaline resistance according to claim 6, characterized in that: Grind to a fineness less than 5 μm.

9. The method for preparing a water-washable ink having strong alkaline resistance according to claim 6, characterized in that: Adjust pH to 8-9.

10. A use of a water-washable ink having strong alkaline resistance as claimed in any one of claims 1 to 5, characterized in that: The water-washable ink is used for printing on film substrates and non-absorbent substrates.

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