阅读说明：本技术 一种基于壳聚糖-铁红基的易干燥水性油墨及其制备方法 (Chitosan-iron oxide red-based easily-dried water-based ink and preparation method thereof ) 是由 廖宇 李冉 邱诗波 潘曦 陈琳 刘文婷 贾伟萍 黄轲 王娜 胡素霞 程占刚 于 2021-10-19 设计创作，主要内容包括：本发明公开一种基于壳聚糖-铁红基的易干燥水性油墨及其制备方法,包括质量份数如下的组分：醋酸1-2份、壳聚糖1-2份、氧化铁红颜料25-28份、乙醇25-29份、防结皮剂0.1-0.5份、催干剂0.1-0.2份、分散剂0.01-0.1份,其制备方法包括K1.将1-2份醋酸、1-2份壳聚糖加入至温度为30-40℃的蒸馏水中,2400-2800r/min下搅拌均匀,制得第一组分,壳聚糖在醋酸的作用下均匀稳定的分散；K2.将0.1-0.5份防结皮剂、25-28份氧化铁红颜料、25-29份乙醇、0.1-0.2份催干剂、0.1-0.3份分散剂加入至温度为55-65℃的蒸馏水中,超声分散,得第二组分；K3.将第二组分加入至第一组分中,搅拌混合并研磨,即得速干剂基于壳聚糖-铁红基的易干燥水性油墨,即用即配,所制备的水性油墨干燥快,可避免印刷纸张破裂。(The invention discloses a chitosan-iron oxide red-based easily-dried water-based ink and a preparation method thereof, wherein the ink comprises the following components in parts by weight: 1-2 parts of acetic acid, 1-2 parts of chitosan, 25-28 parts of iron oxide red pigment, 25-29 parts of ethanol, 0.1-0.5 part of anti-skinning agent, 0.1-0.2 part of drier and 0.01-0.1 part of dispersant, wherein the preparation method comprises the steps of adding K1. to 1-2 parts of acetic acid and 1-2 parts of chitosan into distilled water with the temperature of 30-40 ℃, uniformly stirring at 2400-2800r/min to prepare a first component, and uniformly and stably dispersing the chitosan under the action of the acetic acid; K2. adding 0.1-0.5 part of anti-skinning agent, 25-28 parts of iron oxide red pigment, 25-29 parts of ethanol, 0.1-0.2 part of drier and 0.1-0.3 part of dispersing agent into distilled water at the temperature of 55-65 ℃, and performing ultrasonic dispersion to obtain a second component; K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the chitosan-iron red-based easily-dried water-based ink as a quick drying agent, wherein the quick drying agent is prepared immediately after use, and the prepared water-based ink is quick to dry and can avoid the fracture of printing paper.)

1. The chitosan-iron oxide red-based easily-dried water-based ink is characterized by comprising the following components in parts by weight: 1-2 parts of acetic acid, 1-2 parts of chitosan, 25-28 parts of iron oxide red pigment, 25-29 parts of ethanol, 0.1-0.5 part of anti-skinning agent, 0.1-0.2 part of drier and 0.01-0.3 part of dispersant.

2. The chitosan-iron oxide red-based easy-to-dry water-based ink as claimed in claim 1, wherein the anti-skinning agent is one or more of methyl ethyl ketoxime, butyraldehyde oxime and cyclohexanone oxime.

3. The chitosan-iron oxide red-based water-based ink easy to dry as claimed in claim 1, wherein the drier is one or more of sodium alginate and potassium alginate.

4. The easy-to-dry aqueous ink based on chitosan-iron oxide red as claimed in claim 1, wherein said dispersant is maleic anhydride-acrylic acid-butyl acrylate copolymer.

5. The chitosan-iron oxide red-based easy-to-dry water-based ink as claimed in claim 4, wherein the preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in a solvent, and heating in a water bath to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath to obtain a polymer crude product;

s3, adjusting the pH of the polymer crude product to 7-8 with alkali, then dropwise adding the polymer crude product into acetone, standing and separating, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

6. The chitosan-iron oxide red-based easy-to-dry water-based ink as claimed in claim 5, wherein the solvent is an aqueous solution of isopropyl alcohol.

7. The chitosan-iron oxide red-based water-based ink easy to dry as claimed in claim 5, wherein the alkali is one or more of NaOH and KOH.

8. The chitosan-iron oxide red-based easy-to-dry water-based ink as claimed in claim 5, wherein the water bath temperature of the steps S1 and S2 is 50-90 ℃.

9. The chitosan-iron oxide red-based easy-to-dry water-based ink as claimed in claim 5, wherein the dropping speed in step S3 is 3-5 drops/min.

10. A method for preparing the chitosan-iron oxide red based easy-drying water-based ink according to any one of claims 1 to 9, comprising the following steps:

K1. adding 1-2 parts of acetic acid and 1-2 parts of chitosan into distilled water at the temperature of 30-40 ℃, and uniformly stirring at 2400-;

K2. adding 0.1-0.5 part of anti-skinning agent, 25-28 parts of iron oxide red pigment, 25-29 parts of ethanol, 0.1-0.2 part of drier and 0.01-0.1 part of dispersing agent into distilled water at the temperature of 55-65 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the chitosan-iron red-based easily-dried water-based ink.

Technical Field

The invention relates to the field of edible ink, in particular to chitosan-iron oxide red-based easily-dried water-based ink and a preparation method thereof.

Technical Field

Printing inks play an extremely important role in packaging printing as a coloring matter. However, the traditional ink contains part of harmful substances in the raw material composition, for example, a large amount of solvent-based ink applied to soft plastic package printing at present generally contains Volatile Organic Compounds (VOC), so that the traditional ink has great harm to human bodies, and is particularly harmful to the surface printing of food, medicines, cigarette and wine packages, edible packaging materials, children toys and pet foods. Although, the goal has begun to move towards VOC-free environmentally friendly inks, such as alcohol-soluble inks and water-soluble inks, which are less in the market share. The alcohol-soluble ink has the greatest advantages that no special requirements are required on equipment, the equipment is not disturbed in cost for manufacturers in the aspect of equipment modification, meanwhile, the alcohol-soluble ink has the characteristics of high printing speed, low odor and the like, and the problems that toluene ink is harmful to health, solvent residue influences the quality of packaged food and the like can be solved. However, the ink has high production cost of raw materials, generally contains vegetable oil and ester solvents or a small amount of benzene, can really adopt ethanol as the solvent in a very small amount, so that the ink has short service life, and cannot be safely and fearlessly sprayed and printed on the surfaces of food and medicines. Meanwhile, compared with alcohol-soluble ink, the water-based ink has better food sanitation and safety, and can reduce resource consumption and reduce environmental protection cost; the safety of the working environment is improved, and the health of the contact operators is guaranteed.

The research, development and application of the water-based ink are less harmful and less polluted, so that the pollution-free green packaging printing material is the inevitable requirement for the development of green packaging, the research and development of the water-based ink becomes the mainstream of the printing industry, and particularly for the food packaging industry, the water-based edible ink is required to be used.

There are many studies on water-based edible ink, for example, in the prior art, chinese patent publication No. CN201210128908.1 discloses an edible water-based ink and a preparation method thereof, the ink comprises the following components: 60-85% of mineral water, 2-8% of cane sugar, 2-6% of pigment, 2-8% of thickening agent, 2-10% of salt and 5-20% of auxiliary agent, and the preparation method of the ink comprises the following steps: a. weighing the components according to the weight percentage; b. putting the mineral water into a food stirrer, adding a thickening agent and an auxiliary agent while stirring, and continuously stirring to obtain a colloidal solution; c. sequentially adding sucrose, salt and pigment into the colloidal solution, and stirring to obtain a mixed solution; d. the mixed solution is ground by a three-roller grinder and then is subjected to filter pressing, the filtrate is edible water-based ink, the components are safe and edible, the preparation method is simple, the operability is good, the cost is low, the investment is low, but the defects that the drying is slow, the moisture absorption is excessive, the printed paper such as napkin paper or paper bag is broken and the like exist in the invention.

Disclosure of Invention

In order to solve the problems, the invention provides the chitosan-iron oxide red-based water-based ink easy to dry and the preparation method thereof.

The technical scheme provided by the invention is that the chitosan-iron oxide red-based easily-dried water-based ink comprises the following components in parts by weight: 1-2 parts of acetic acid, 1-2 parts of chitosan, 25-28 parts of iron oxide red pigment, 25-29 parts of ethanol, 0.1-0.5 part of anti-skinning agent, 0.1-0.2 part of drier and 0.01-0.1 part of dispersant, wherein the chitosan can be used as a binder resin for preparing edible ink due to excellent properties such as edibility, degradability, film-forming property and the like, can be coated with protective pigment and has synergistic effect with the dispersant to maintain the stability and continuous dispersibility of an ink system; the iron oxide red pigment as edible inorganic pigment has high weather resistance, solvent resistance and chemical stability; acetic acid and ethanol are used as a cosolvent of chitosan to increase the solubility of chitosan.

Preferably, the anti-skinning agent is one or more of methyl ethyl ketoxime, butyraldehyde oxime and cyclohexanone oxime, and the anti-skinning agent has good co-solubility with chitosan and iron oxide red pigment, so that the fluidity of the ink is increased, and skinning after the ink is dried is prevented.

Preferably, the drier is one or more of sodium alginate and potassium alginate, on one hand, a large amount of primary amino groups are arranged on chitosan molecular chains, a large amount of carboxyl groups are arranged on alginate molecular chains, under the action of electrostatic force, a polyelectrolyte membrane can be formed through positive and negative charge attraction, drying is accelerated, on the other hand, the water absorption of the chitosan can be reduced by mixing alginate and chitosan molecules, after the water-based ink is sprayed on a paper printed matter, the water absorption in the air is reduced, the continuous increase of water on the paper can not be caused, and the paper is prevented from being broken due to excessive moisture absorption.

Preferably, the dispersing agent is maleic anhydride-acrylic acid-butyl acrylate copolymer, the iron oxide red pigment in the scheme is easy to agglomerate to form secondary particles, the service performance of the iron oxide red pigment is influenced, and the maleic anhydride-acrylic acid-butyl acrylate copolymer has excellent dispersing effect on the iron oxide red pigment due to the fact that the maleic anhydride-acrylic acid-butyl acrylate copolymer has a solvation chain and an anchoring group.

Preferably, the preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in a solvent, heating in a constant-temperature water bath, and stirring constantly at a constant speed by using a JJ-1 type digital display electric stirrer to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, heating in a water bath to obtain a polymer crude product, and initiating a polymerization reaction of maleic anhydride, acrylic acid and butyl acrylate by using ammonium persulfate as an initiator, wherein the amount of the initiator is 1-8% of the mass of the maleic anhydride, the acrylic acid and the butyl acrylate;

s3, adjusting the pH of the polymer crude product to 7-8 with alkali, then dropwise adding the polymer crude product into acetone, standing and separating, and taking a precipitate; on the other hand, the polymer is easier to be purified and solidified after being neutralized into sodium salt;

s4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer;

preferably, the solvent is an isopropanol aqueous solution, isopropanol is used as a chain transfer agent for reaction, and the mass fraction of the isopropanol in the isopropanol aqueous solution is 1-20%;

preferably, the alkali is one or more of NaOH and KOH, and strong alkali is favorable for converting the polymer into the ionic dispersing agent;

preferably, the water bath temperature of the steps S1 and S2 is 50-90 ℃;

preferably, the dropping speed in the step S3 is 3 to 5 drops/min, which is favorable for sufficient precipitation of the polymer;

further, a preparation method of the chitosan-iron oxide red-based easy-to-dry water-based ink is also provided, and comprises the following steps:

K1. adding 1-2 parts of acetic acid and 1-2 parts of chitosan into distilled water at the temperature of 30-40 ℃, and uniformly stirring at 2400-;

K2. adding 0.1-0.5 part of anti-skinning agent, 25-28 parts of iron oxide red pigment, 25-29 parts of ethanol, 0.1-0.2 part of drier and 0.1-0.3 part of dispersing agent into distilled water at the temperature of 55-65 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the chitosan-iron red-based easily-dried water-based ink, namely preparing the ink immediately after use.

In the scheme, chitosan can be used as a connecting material resin to prepare edible ink due to excellent properties such as edibility, degradability, film-forming property and the like, can be coated with a protective pigment and cooperates with a dispersing agent to maintain the stability and continuous dispersibility of an ink system, and an iron oxide red pigment as an edible inorganic pigment has high weather resistance, solvent resistance and chemical stability, but the chitosan has high hygroscopicity, so that the chitosan has the defects of slow drying, easy paper shrinkage and the like as a water-based ink raw material. On the other hand, the alginate and the chitosan molecules are mixed to reduce the water absorption of the chitosan, and after the water-based ink is sprayed on a paper printed matter, the water absorption of the water-based ink in the air is reduced, so that the water cannot be continuously increased on the paper, the paper is prevented from being broken due to excessive moisture absorption, and the alginate cannot influence the light transmittance of the printed matter; in addition, the iron oxide red pigment in the scheme is easy to agglomerate to form secondary particles, so that the service performance of the iron oxide red pigment is influenced, and the maleic anhydride-acrylic acid-butyl acrylate copolymer has a solvation chain and an anchoring group and has a good dispersing effect on the iron oxide red pigment.

The invention has the beneficial effects that:

1. the chitosan is used as the binder resin and the iron oxide red pigment is used as the edible raw material to prepare the water-based ink, so that the water-based ink is safe and environment-friendly;

2. alginate is used as a drier to accelerate drying of the water-based ink, and cooperates with an anti-skinning agent to accelerate drying and prevent paper shrinkage;

3. the alginate is mixed with chitosan molecules to reduce the water absorption of chitosan, and after the water-based ink is sprayed on paper printed matters, the water absorption of the paper printed matters to the air is reduced, so that the water cannot be continuously increased on the paper, and the paper is prevented from being broken due to the fact that the water permeates into the paper due to excessive moisture absorption;

4. the maleic anhydride-acrylic acid-butyl acrylate copolymer is used as a dispersant to disperse the iron oxide red pigment, prevent flocculation and enhance the stability of the water-based ink.

Drawings

FIG. 1 is the apparent result of precipitation for different inks;

FIG. 2 shows the results of fineness measurements for different inks;

FIG. 3 is a comparison of moisture content of different ink prints after drying;

FIG. 4 shows a comparison of the damage and shrinkage after drying of different ink prints.

Detailed Description

The present invention will be described in further detail with reference to examples.

It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available by purchase.

Example 1

The chitosan-iron oxide red-based easily-dried water-based ink comprises the following components in parts by weight: 1 part of acetic acid, 1 part of chitosan, 25 parts of iron oxide red pigment, 25 parts of ethanol, 0.1 part of methyl ethyl ketoxime, 0.1 part of sodium alginate and 0.01 part of maleic anhydride-acrylic acid-butyl acrylate copolymer.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 90 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at 60 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 7 by using NaOH, dropwise adding the polymer crude product into acetone at a speed of 4 drops/min, standing for separation, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Example 2

The chitosan-iron oxide red-based easily-dried water-based ink comprises the following components in parts by weight: 2 parts of acetic acid, 2 parts of chitosan, 28 parts of iron oxide red pigment, 29 parts of ethanol, 0.5 part of butyraldehyde oxime, 0.2 part of potassium alginate and 0.3 part of maleic anhydride-acrylic acid-butyl acrylate copolymer.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 90 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at 90 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 8 by using NaOH, dropwise adding the polymer crude product into acetone at a speed of 5 drops/min, standing for separation, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Example 3

The chitosan-iron oxide red-based easily-dried water-based ink comprises the following components in parts by weight: 1.5 parts of acetic acid, 1.2 parts of chitosan, 26 parts of iron oxide red pigment, 28 parts of ethanol, 0.2 part of cyclohexanone oxime, 0.15 part of sodium alginate and 0.1 part of maleic anhydride-acrylic acid-butyl acrylate copolymer.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 80 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at 70 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 7.5 by using NaOH, dropwise adding the polymer crude product into acetone at the speed of 3 drops/minute, standing and separating, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Example 4

A preparation method of easy-drying water-based ink based on chitosan-iron oxide red comprises the following steps:

K1. adding 1 part of acetic acid and 1 part of chitosan into distilled water at the temperature of 30 ℃, and uniformly stirring at 2400r/min to prepare a first component;

K2. adding 0.1 part of methyl ethyl ketoxime, 25 parts of iron oxide red pigment, 25 parts of ethanol, 0.1 part of sodium alginate and 0.01 part of maleic anhydride-acrylic acid-butyl acrylate copolymer into distilled water at the temperature of 55 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the chitosan-iron red-based easily-dried water-based ink.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 50 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at 50 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 7.5 by using NaOH, dropwise adding the polymer crude product into acetone at the speed of 3 drops/minute, standing and separating, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Example 5

A preparation method of easy-drying water-based ink based on chitosan-iron oxide red comprises the following steps:

K1. adding 2 parts of acetic acid and 2 parts of chitosan into distilled water at the temperature of 40 ℃, and uniformly stirring at 2800r/min to obtain a first component;

K2. adding 0.5 part of butyraldehyde oxime, 28 parts of iron oxide red pigment, 29 parts of ethanol, 0.2 part of potassium alginate and 0.1 part of maleic anhydride-acrylic acid-butyl acrylate copolymer into distilled water at the temperature of 65 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the chitosan-iron red-based easily-dried water-based ink.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 90 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at the temperature of 80 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 7 by using NaOH, dropwise adding the polymer crude product into acetone at a speed of 5 drops/min, standing for separation, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Example 6

A preparation method of easy-drying water-based ink based on chitosan-iron oxide red comprises the following steps:

K1. adding 1.2 parts of acetic acid and 1.5 parts of chitosan into distilled water with the temperature of 35 ℃, and uniformly stirring at 2800r/min to prepare a first component;

K2. adding 0.2 part of cyclohexanone oxime, 25-28 parts of iron oxide red pigment, 26 parts of ethanol, 0.2 part of sodium alginate and 0.05 part of maleic anhydride-acrylic acid-butyl acrylate copolymer into distilled water at the temperature of 60 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the chitosan-iron red-based easily-dried water-based ink.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 90 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at the temperature of 80 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 7 by using NaOH, dropwise adding the polymer crude product into acetone at a speed of 5 drops/min, standing for separation, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Comparative example 1

A preparation method of water-based ink comprises the following steps:

K1. adding 2 parts of acetic acid and 2 parts of chitosan into distilled water at the temperature of 40 ℃, and uniformly stirring at 2800r/min to obtain a first component;

K2. adding 28 parts of iron oxide red pigment and 29 parts of ethanol into distilled water at the temperature of 65 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the water-based ink.

Comparative example 2

A preparation method of water-based ink comprises the following steps:

K1. adding 1.2 parts of acetic acid and 1.5 parts of chitosan into distilled water with the temperature of 35 ℃, and uniformly stirring at 2800r/min to prepare a first component;

K2. adding 0.2 part of methyl ethyl ketoxime, 25-28 parts of iron oxide red pigment and 26 parts of ethanol into distilled water at the temperature of 60 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the water-based ink.

Comparative example 3

A preparation method of water-based ink comprises the following steps:

K1. adding 1.2 parts of acetic acid and 1.5 parts of chitosan into distilled water with the temperature of 35 ℃, and uniformly stirring at 2800r/min to prepare a first component;

K2. adding 0.2 part of methyl ethyl ketoxime, 25-28 parts of iron oxide red pigment, 26 parts of ethanol and 0.2 part of sodium alginate into distilled water at the temperature of 60 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the water-based ink.

Comparative example 4

A preparation method of water-based ink comprises the following steps:

K1. adding 2 parts of acetic acid and 2 parts of chitosan into distilled water at the temperature of 40 ℃, and uniformly stirring at 2800r/min to obtain a first component;

K2. adding 0.5 part of butyraldehyde oxime, 28 parts of iron oxide red pigment, 29 parts of ethanol and 0.1 part of maleic anhydride-acrylic acid-butyl acrylate copolymer into distilled water at the temperature of 65 ℃, and performing ultrasonic dispersion to obtain a second component;

K3. and adding the second component into the first component, stirring, mixing and grinding to obtain the water-based ink.

The preparation method of the maleic anhydride-acrylic acid-butyl acrylate copolymer comprises the following steps:

s1, dispersing maleic anhydride, acrylic acid and butyl acrylate in an isopropanol water solution, and heating in a water bath at 90 ℃ to obtain a mixed solution;

s2, adding an ammonium persulfate aqueous solution into the mixed solution, and heating in a water bath at the temperature of 80 ℃ to obtain a polymer crude product;

s3, adjusting the pH value of the polymer crude product to 7 by using NaOH, dropwise adding the polymer crude product into acetone at a speed of 5 drops/min, standing for separation, and taking a precipitate;

and S4, dissolving the precipitate with water, and then precipitating with acetone to obtain the maleic anhydride-acrylic acid-butyl acrylate copolymer.

Test method

The inks obtained in examples 4 to 6 and comparative examples 1 to 4 were tested for their different appearance phenomena, and the ink was observed to settle within 10min, with the results shown in FIG. 1;

the inks obtained in examples 4 to 6 and comparative examples 1 to 4 were subjected to fineness measurement according to the fineness measurement method specified in GB/T6753.1-2007 measurement of fineness of grind of colored paint, varnish and printing ink, and the results are shown in FIG. 2;

the inks obtained in examples 4 to 6 and comparative examples 1 to 4 were used for napkin printing, and the drying speed of the inks and the breakage and shrinkage of the napkin after printing were tested, wherein the drying speed was tested as follows: respectively coating the printing ink on napkin paper with the thickness of 2mm, drying for 20min at 60 ℃, testing the moisture content on the napkin paper by using a moisture tester, wherein the higher the moisture content is, the slower the drying speed is, fig. 3 is a comparison result of the moisture content of different printing ink printed matters after drying, and fig. 4 is a comparison result of the damage condition and the shrinkage condition of different printing ink printed matters after drying.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.