An environmentally friendly anti-scaling auxiliary agent and preparation method thereof

Abstract

The present invention relates to an environmentally friendly anti-skinning auxiliary agent and a preparation method thereof, and belongs to the technical field of water-based inks. The formula comprises modified chitosan oligosaccharides, polyether-modified polysiloxanes, polyvinyl alcohol, water-soluble malonate carbon quantum dots and deionized water as ingredients. Chitosan oligosaccharides have good water solubility due to their small relative molecular mass, and are easy to form a soft and uniform film layer, which effectively prevents ink from skinning and maintains wetness; by introducing chlorogenic acid, the antioxidant efficiency of chitosan oligosaccharides is significantly improved, while retaining its film-forming and moisturizing advantages. Polyether-modified polysiloxanes and polyvinyl alcohol jointly promote the rapid onset of ingredients, enhance stability and durability. The introduction of water-soluble malonate carbon quantum dots improves photostability and reduces photooxidation reactions. The auxiliary agent of the present invention has excellent anti-skinning efficiency, strong antioxidant properties and environmental protection, and most of the raw materials are derived from nature. No harmful solvents or catalysts are required in the preparation process, which conforms to the concept of green chemistry and is harmless to the environment and human health.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based inks and relates to an environmentally friendly anti-skinning auxiliary agent and a preparation method thereof. Background Art

[0002] As an environmentally friendly printing material, water-based ink uses water as the main solvent, has low volatile organic compound (VOCs) emissions, excellent safety and good printing performance. These characteristics make water-based ink widely used in the printing industry, especially in food packaging, household goods and electronic products. However, water-based ink is prone to skinning during storage and use, that is, the ink surface dries to form an uneven hard film. Skinning not only leads to a decline in product quality, but also may affect production efficiency and cost.

[0003] In the prior art, there are already some additives for preventing ink skinning. However, these additives are mainly composed of artificial synthetic high molecular polymers, and often have some problems, such as large addition amount, poor environmental protection, great impact on ink performance, unsatisfactory anti-skinning effect, etc. Due to the particularity of water-based ink, the environmental protection and impact of anti-skinning additives on ink performance in the field of water-based ink are required to be higher. Therefore, it is of great practical significance to develop an environmentally friendly anti-skinning additive to solve the skinning problem of water-based ink. Summary of the invention

[0004] The object of the present invention is to provide an environmentally friendly anti-scaling auxiliary agent and a preparation method thereof, which has the characteristics of being environmentally friendly and non-toxic, having a small additive amount and high anti-scaling efficiency.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An environmentally friendly anti-skinning auxiliary agent, the environmentally friendly anti-skinning auxiliary agent comprises the following components in parts by weight: 160-180 parts of deionized water, 30-40 parts of polyether-modified polysiloxane, 10-20 parts of polyvinyl alcohol, 3-5 parts of modified chitosan oligosaccharide, and 0.3-0.5 parts of water-soluble malonic acid carbon quantum dots.

[0007] Wherein, the preparation method of the modified chitosan oligosaccharide is as follows:

[0008] S1-1: Add 3-5 parts of chitosan oligosaccharide to 100-120 parts of PBS buffer solution, stir ultrasonically for 30 min, add 6-10 parts of chlorogenic acid, and continue stirring at 50 °C for 30 min to obtain mixed solution A;

[0009] S1-2: Add 2-3 parts of tyrosinase to the mixed solution A at 45°C, introduce oxygen and stir for 2-3 hours in the dark, centrifuge and wash with deionized water and ethanol, and then freeze-dry to obtain the modified chitosan oligosaccharide.

[0010] Furthermore, the enzyme activity of tyrosinase in the S1-2 is 5 kU / g.

[0011] Furthermore, the oxygen flow rate in S1-2 is 100-120 mL / min.

[0012] Furthermore, the freeze drying in S1-2 is carried out at -45°C for 12 h.

[0013] Furthermore, the preparation method of the water-soluble malonic acid carbon quantum dots is as follows:

[0014] Urea and malonic acid were mixed, added to deionized water so that the solid-liquid mass ratio was 1:19, ultrasonicated for 30 min, and then placed in a reactor for heating at a temperature of 180-200 °C. After cooling to room temperature, the mixture was centrifuged and filtered, and then dialyzed for 6 h using a dialysis bag with a molecular weight of 1000 KD, and then freeze-dried at -30 °C for 12 h to obtain the water-soluble malonic acid carbon quantum dots.

[0015] Furthermore, urea and malonic acid are mixed in a molar ratio of 1:1.

[0016] Furthermore, the reactor heating time is 4 to 5 h.

[0017] A method for preparing an environmentally friendly anti-skinning auxiliary agent, the specific steps of the preparation method are as follows:

[0018] S8-1: Add half the weight of deionized water into the material tank according to the formula, add polyether-modified polysiloxane, and stir for 30 minutes;

[0019] S8-2: Increase the stirring speed to 750-850 r / min, add polyvinyl alcohol, modified chitosan oligosaccharide, water-soluble malonic acid carbon quantum dots and the remainder of deionized water into the material tank in sequence, and continue stirring for 30 min to obtain the environmentally friendly anti-skinning additive.

[0020] Furthermore, the stirring speed in S8-1 is 600~700 r / min.

[0021] The invention discloses an application of an environmentally friendly anti-skinning auxiliary agent in water-based ink, wherein the addition amount of the environmentally friendly anti-skinning auxiliary agent is 0.1-1.5 wt.%.

[0022] As a high molecular surfactant, polyether-modified polysiloxane can effectively reduce surface tension, allowing the additive to penetrate into the ink more effectively, promoting the other ingredients to work faster, and improving the anti-skinning efficiency of the overall additive. As an environmentally friendly surfactant, polyether-modified polysiloxane has good biocompatibility, ensuring that it will not cause harm to the environment or human body during use, which is in line with the concept of sustainable development.

[0023] Compared with traditional chitosan, chitosan oligosaccharides show more superior properties, such as a smaller relative molecular weight, which gives chitosan oligosaccharides better water solubility and makes it easier to form a soft and uniform film layer during application. It can not only effectively prevent the ink surface from forming a crust, but also maintain the wetness of the ink to a certain extent, achieving the effect of film formation and moisturizing. In terms of anti-oxidation, chitosan oligosaccharides show good antioxidant properties through chelation with metal ions.

[0024] In order to further improve the antioxidant efficiency of chitosan oligosaccharides, chlorogenic acid, a natural antioxidant, is introduced. Chlorogenic acid can stably provide electrons or hydrogen protons to free radicals, converting free radicals into stable intermediates, thereby effectively inhibiting the occurrence of oxidation reactions. Chlorogenic acid has a stable structure and can continuously and stably exert its antioxidant effect, providing additional antioxidant protection for chitosan oligosaccharides. The combination between chlorogenic acid and chitosan oligosaccharides is promoted by the catalytic oxidation of tyrosinase to prepare modified chitosan oligosaccharides. Modified chitosan oligosaccharides not only inherit the excellent film-forming and moisturizing properties of chitosan oligosaccharides, but also significantly improve their antioxidant efficiency and effectively prevent ink crusting. The raw materials of modified chitosan oligosaccharides are all derived from nature, non-toxic and harmless, and will not cause any negative impact on the environment and human health.

[0025] Polyvinyl alcohol is an excellent water-soluble polymer with good film-forming properties. In anti-skinning additives, it can further enhance the film-forming effect, effectively cover the ink surface, prevent water evaporation and external pollution, and thus extend the shelf life and stability of the ink; the molecular chain of polyvinyl alcohol contains a large number of hydroxyl groups, which can form hydrogen bonds with water molecules, thus having good moisturizing properties. The addition of polyvinyl alcohol can also improve the stability of the entire additive, so that it can maintain good performance under various environmental conditions.

[0026] Water-soluble malonate carbon quantum dots have excellent light absorption capacity, can effectively absorb and disperse light energy, reduce direct exposure and damage to the ink surface, help protect the material from adverse effects such as light aging and light degradation, and can also improve the overall weather resistance and stability of the additive to a certain extent. Functional groups such as carboxyl and hydroxyl groups on the surface of water-soluble malonate carbon quantum dots can interact with other ingredients to form a stable chemical structure, which helps to inhibit the occurrence of photooxidation reactions and extend the service life of the additive.

[0027] Beneficial effects of the present invention:

[0028] (1) Chitosan oligosaccharides have excellent water solubility due to their small relative molecular weight. They are easy to form a soft and uniform film layer, effectively preventing ink from crusting and maintaining its wetness, achieving excellent film-forming and moisturizing functions. By introducing chlorogenic acid, the antioxidant efficiency of chitosan oligosaccharides is significantly improved. The chlorogenic acid structure is stable and can continuously exert antioxidant effects, providing additional protection for chitosan oligosaccharides. Modified chitosan oligosaccharides not only retain the film-forming and moisturizing advantages of chitosan oligosaccharides, but also significantly enhance the antioxidant properties. In addition, the raw materials are naturally non-toxic and harmless to the environment and human health.

[0029] (2) With its low surface tension and excellent lubricity, polyether-modified polysiloxane promotes the rapid onset of the other ingredients and effectively prevents the occurrence of surface crusting; the film-forming and moisturizing properties of polyvinyl alcohol further enhance stability and durability; the introduction of water-soluble malonate carbon quantum dots significantly improves photostability and effectively reduces the occurrence of photooxidation reactions. The anti-skinning additive prepared by mixing deionized water, polyether-modified polysiloxane, polyvinyl alcohol, modified chitosan oligosaccharide and water-soluble malonate carbon quantum dots achieves multiple effects of excellent anti-skinning efficiency, strong antioxidant properties and environmental harmlessness.

[0030] (3) The anti-scaling additive of the present invention is environmentally friendly and harmless. Most of the raw materials are derived from nature, are non-toxic and harmless, and will not cause any negative impact on the environment and human health. The preparation process of the additive does not require the use of harmful solvents or catalysts, which is in line with the concept of green chemistry. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0032] Figure 1 The anti-skinning efficiency of the anti-skinning agent prepared in Example 1 and the blank control in the ink at different storage times;

[0033] Figure 2 The anti-skinning efficiency of the anti-skinning agent prepared in Example 1 at different ink concentrations;

[0034] Figure 3 The anti-skinning efficiency of the anti-skinning agent prepared in Example 1 at different addition amounts. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0036] In the embodiments of the present invention and the comparative examples:

[0037] Chitosan oligosaccharide: purchased from Wuhan Xingzhongcheng Technology Co., Ltd., purity: 99%;

[0038] Tyrosinase: purchased from Shanghai Baoman Biotechnology Co., Ltd., CAS: 9002-10-2, enzyme activity: 5 kU / g;

[0039] PBS buffer solution: purchased from Shanghai Yiji Industrial Co., Ltd., pH = 7.0;

[0040] Chlorogenic acid: purchased from Shanghai Shidande Standard Technology Service Co., Ltd., CAS: 327-97-9, purity: ≥98%;

[0041] Ethanol: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 64-17-5, purity: anhydrous grade;

[0042] Urea: purchased from Xuzhou Songyu Chemical Technology Co., Ltd., CAS: 57-13-6, purity: 99.0%;

[0043] Malonic acid: purchased from Wuhan Songshi Technology Co., Ltd., CAS: 141-82-2, purity: 99.5%;

[0044] Polyvinyl alcohol: purchased from Shanghai Yanze Chemical Co., Ltd., CAS: 9002-89-5, purity: 99%;

[0045] Polyether modified polysiloxane: purchased from Shanghai Jiader Chemical Technology Co., Ltd., purity: 98%.

[0046] Example 1

[0047] An environmentally friendly anti-skinning auxiliary agent, the environmentally friendly anti-skinning auxiliary agent comprises the following components in parts by weight: 170 parts of deionized water, 35 parts of polyether-modified polysiloxane, 15 parts of polyvinyl alcohol, 4 parts of modified chitosan oligosaccharide, 0.4 parts of water-soluble malonic acid carbon quantum dots,

[0048] Wherein, the preparation method of the modified chitosan oligosaccharide is as follows:

[0049] S1-1: 4 parts of chitosan oligosaccharide were added to 110 parts of PBS buffer solution, ultrasonically stirred for 30 min, 8 parts of chlorogenic acid were added, and stirring was continued at 50 °C for 30 min to obtain a mixed solution A;

[0050] S1-2: Add 2.5 parts of tyrosinase with an enzyme activity of 5 kU / g to the mixed solution A at 45°C, introduce oxygen and stir in the dark for 2.5 h at an oxygen introduction rate of 110 mL / min, centrifuge and wash with deionized water and ethanol, and then freeze-dry at -45°C for 12 h to obtain the modified chitosan oligosaccharide.

[0051] The preparation method of the water-soluble malonic acid carbon quantum dots is as follows:

[0052] Urea and malonic acid were mixed in a molar ratio of 1:1, added to deionized water so that the solid-liquid mass ratio was 1:19, ultrasonicated for 30 min, and then placed in a reactor and heated for 4.5 h at a heating temperature of 190 ° C. After cooling to room temperature, centrifuged and filtered, dialyzed for 6 h using a dialysis bag with a molecular weight of 1000 KD, and then freeze-dried at -30 ° C for 12 h to obtain the water-soluble malonic acid carbon quantum dots.

[0053] A method for preparing an environmentally friendly anti-skinning auxiliary agent, the specific steps of the preparation method are as follows:

[0054] S8-1: Add half the weight of deionized water into the material tank according to the formula, add polyether-modified polysiloxane, and stir at 650 r / min for 30 min;

[0055] S8-2: Increase the stirring speed to 800 r / min, add polyvinyl alcohol, modified chitosan oligosaccharide, water-soluble malonic acid carbon quantum dots and the remainder of deionized water into the material tank in sequence, and continue stirring for 30 min to obtain the environmentally friendly anti-skinning additive.

[0056] The anti-skinning additives prepared in the examples and comparative examples were added to sheet-fed offset red ink to test the anti-skinning efficiency. The test results are as follows: Figure 1 shown.

[0057] Example 2

[0058] An environmentally friendly anti-skinning auxiliary agent, the environmentally friendly anti-skinning auxiliary agent comprises the following components in parts by weight: 160 parts of deionized water, 30 parts of polyether-modified polysiloxane, 10 parts of polyvinyl alcohol, 3 parts of modified chitosan oligosaccharide, 0.3 parts of water-soluble malonic acid carbon quantum dots,

[0059] Wherein, the preparation method of the modified chitosan oligosaccharide is as follows:

[0060] S1-1: Add 3 parts of chitosan oligosaccharide to 100 parts of PBS buffer solution, stir ultrasonically for 30 min, add 6 parts of chlorogenic acid, and continue stirring at 50 °C for 30 min to obtain mixed solution A;

[0061] S1-2: Add 2 portions of tyrosinase with an enzyme activity of 5 kU / g to the mixed solution A at 45°C, introduce oxygen and stir in the dark for 2 h at an oxygen introduction rate of 100 mL / min, centrifuge and wash with deionized water and ethanol, and then freeze-dry at -45°C for 12 h to obtain the modified chitosan oligosaccharide.

[0062] The preparation method of the water-soluble malonic acid carbon quantum dots is as follows:

[0063] Urea and malonic acid were mixed in a molar ratio of 1:1, added to deionized water so that the solid-liquid mass ratio was 1:19, ultrasonicated for 30 minutes, and then placed in a reactor and heated for 4 hours at a heating temperature of 180°C. After cooling to room temperature, the mixture was centrifuged and filtered, and then dialyzed for 6 hours using a dialysis bag with a molecular weight of 1000 KD, and then freeze-dried at -30°C for 12 hours to obtain the water-soluble malonic acid carbon quantum dots.

[0064] A method for preparing an environmentally friendly anti-skinning auxiliary agent, the specific steps of the preparation method are as follows:

[0065] S8-1: Add half the weight of deionized water into the material tank according to the formula, add polyether-modified polysiloxane, and stir at 600 r / min for 30 min;

[0066] S8-2: Increase the stirring speed to 750 r / min, add polyvinyl alcohol, modified chitosan oligosaccharide, water-soluble malonic acid carbon quantum dots and the remainder of deionized water into the material tank in sequence, and continue stirring for 30 min to obtain the environmentally friendly anti-skinning additive.

[0067] Example 3

[0068] An environmentally friendly anti-skinning auxiliary agent, the environmentally friendly anti-skinning auxiliary agent comprises the following components by weight: 180 parts of deionized water, 40 parts of polyether-modified polysiloxane, 20 parts of polyvinyl alcohol, 5 parts of modified chitosan oligosaccharide, 0.5 parts of water-soluble malonic acid carbon quantum dots,

[0069] Wherein, the preparation method of the modified chitosan oligosaccharide is as follows:

[0070] S1-1: 5 parts of chitosan oligosaccharide were added to 120 parts of PBS buffer solution, ultrasonically stirred for 30 min, 10 parts of chlorogenic acid were added, and stirring was continued at 50 °C for 30 min to obtain a mixed solution A;

[0071] S1-2: Add 3 portions of tyrosinase with an enzyme activity of 5 kU / g to the mixed solution A at 45°C, introduce oxygen and stir in the dark for 3 h at an oxygen introduction rate of 120 mL / min, centrifuge and wash with deionized water and ethanol, and then freeze-dry at -45°C for 12 h to obtain the modified chitosan oligosaccharide.

[0072] The preparation method of the water-soluble malonic acid carbon quantum dots is as follows:

[0073] Urea and malonic acid were mixed in a molar ratio of 1:1, added to deionized water so that the solid-liquid mass ratio was 1:19, ultrasonicated for 30 minutes, and then placed in a reactor and heated for 5 hours at a heating temperature of 200°C. After cooling to room temperature, the mixture was centrifuged and filtered, and then dialyzed for 6 hours using a dialysis bag with a molecular weight of 1000 KD, and then freeze-dried at -30°C for 12 hours to obtain the water-soluble malonic acid carbon quantum dots.

[0074] A method for preparing an environmentally friendly anti-skinning auxiliary agent, the specific steps of the preparation method are as follows:

[0075] S8-1: Add half the weight of deionized water into the material tank according to the formula, add polyether-modified polysiloxane, and stir at 700 r / min for 30 min;

[0076] S8-2: Increase the stirring speed to 850 r / min, add polyvinyl alcohol, modified chitosan oligosaccharide, water-soluble malonic acid carbon quantum dots and the remainder of deionized water into the material tank in sequence, and continue stirring for 30 min to obtain the environmentally friendly anti-skinning additive.

[0077] Comparative Example 1

[0078] The chitosan oligosaccharide was not modified, and the remaining steps were consistent with those in Example 1.

[0079] Comparative Example 2

[0080] Chitosan oligosaccharide and chlorogenic acid were mixed in a mass ratio of 1:2 to replace the modified chitosan oligosaccharide, and the remaining steps were consistent with Example 1.

[0081] Comparative Example 3

[0082] Without adding water-soluble malonic acid carbon quantum dots, the remaining steps were consistent with those in Example 1.

[0083] Performance test: The anti-skinning additives prepared in the examples and comparative examples were added to the water-based ink at a ratio of 1 wt.% to test the skinning (gel) content. The original weight of the water-based ink was w1. The surface skinned material was removed and weighed to obtain a weight w2. The skinning (gel) content was calculated, i.e., the skinning (gel) content = w2 / w1×100%. The experimental data are summarized in the following table.

[0084]

[0085] It can be seen from the data of the embodiments and comparative examples that the anti-skinning additive prepared from deionized water, polyether-modified polysiloxane, polyvinyl alcohol, modified chitosan oligosaccharide and water-soluble malonic acid carbon quantum dots has an excellent anti-skinning effect when added to water-based ink.

[0086] Depend on Figure 1It can be seen that the anti-skinning agent prepared in Example 1 can well inhibit the formation of ink skinning (gel) during different ink storage times; Figure 2 It can be seen that the anti-skinning agent prepared in Example 1 can inhibit the skinning (gelling) of inks of different concentrations, and can also take effect quickly in high-concentration inks; Figure 3 It can be seen that the anti-skinning auxiliary agent prepared in Example 1 can quickly inhibit the skinning (gelling) effect at a relatively low addition amount, has high quality and low price, and can significantly reduce the production cost.

[0087] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly anti-skinning auxiliary agent, characterized in that: The environmentally friendly anti-skinning auxiliary agent comprises the following ingredients by weight: 160-180 parts of deionized water, 30-40 parts of polyether-modified polysiloxane, 10-20 parts of polyvinyl alcohol, 3-5 parts of modified chitosan oligosaccharide, and 0.3-0.5 parts of water-soluble malonic acid carbon quantum dots. Wherein, the preparation method of the modified chitosan oligosaccharide is as follows: S1-1: Add 3-5 parts of chitosan oligosaccharide to 100-120 parts of PBS buffer solution, stir ultrasonically for 30 min, add 6-10 parts of chlorogenic acid, and continue stirring at 50 °C for 30 min to obtain mixed solution A; S1-2: Add 2-3 parts of tyrosinase to the mixed solution A at 45°C, introduce oxygen and stir for 2-3 hours in the dark, centrifuge and wash with deionized water and ethanol, and then freeze-dry to obtain the modified chitosan oligosaccharide.

2. An environmentally friendly anti-skinning auxiliary agent according to claim 1, characterized in that: The enzyme activity of tyrosinase in the S1-2 is 5 kU / g.

3. An environmentally friendly anti-skinning auxiliary agent according to claim 1, characterized in that: The oxygen flow rate in S1-2 is 100-120 mL / min.

4. An environmentally friendly anti-skinning auxiliary agent according to claim 1, characterized in that: The freeze-drying step in S1-2 was performed at -45°C for 12 h.

5. An environmentally friendly anti-skinning auxiliary agent according to claim 1, characterized in that: The preparation method of the water-soluble malonic acid carbon quantum dots is as follows: Urea and malonic acid were mixed, added to deionized water so that the solid-liquid mass ratio was 1:19, ultrasonicated for 30 min, and then placed in a reactor for heating at a temperature of 180-200 °C. After cooling to room temperature, the mixture was centrifuged and filtered, and then dialyzed for 6 h using a dialysis bag with a molecular weight of 1000 KD, and then freeze-dried at -30 °C for 12 h to obtain the water-soluble malonic acid carbon quantum dots.

6. An environmentally friendly anti-skinning auxiliary agent according to claim 5, characterized in that: Urea and malonic acid are mixed in a molar ratio of 1:

1.

7. An environmentally friendly anti-skinning auxiliary agent according to claim 5, characterized in that: The reactor heating time is 4~5h.

8. A method for preparing the environmentally friendly anti-skinning auxiliary agent according to any one of claims 1 to 7, characterized in that: The specific steps of the preparation method are as follows: S8-1: Add half the weight of deionized water into the material tank according to the formula, add polyether-modified polysiloxane, and stir for 30 minutes; S8-2: Increase the stirring speed to 750-850 r / min, add polyvinyl alcohol, modified chitosan oligosaccharide, water-soluble malonic acid carbon quantum dots and the remainder of deionized water into the material tank in sequence, and continue stirring for 30 min to obtain the environmentally friendly anti-skinning additive.

9. The method for preparing the environmentally friendly anti-skinning auxiliary agent according to claim 8, characterized in that: The stirring speed in S8-1 is 600-700 r / min.

10. Use of the environmentally friendly anti-skinning additive according to any one of claims 1 to 7 in water-based ink, characterized in that: The added amount of the environmentally friendly anti-skinning auxiliary agent is 0.1-1.5 wt.%.

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