CN111196903A

CN111196903A - A kind of reversible thermochromic ink and preparation method and application thereof

Info

Publication number: CN111196903A
Application number: CN201911396034.6A
Authority: CN
Inventors: 钟云飞; 刘丹飞; 崔子杰; 游诗英
Original assignee: Hunan University of Technology
Current assignee: Hunan University of Technology
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-05-26

Abstract

The invention discloses a reversible thermochromic ink and a preparation method and application thereof. Crystal violet lactone is used as a color-developing agent, and boric acid is used as a color-developing agent to prepare a thermochromic material, and the thermochromic material is added into the ink to give The thermochromic effect of the ink is light blue at room temperature, and gray-white under the heat source such as a lighter, which realizes the anti-counterfeiting function of the ink. The color of the printed image and text can be changed by a certain heat source. After removing the heat source for a period of time, the color changes. It can be restored; the identification method is convenient and fast, and the thermochromic color is reversible.

Description

Reversible thermochromic ink and preparation method and application thereof

Technical Field

The invention relates to the technical field of ink, in particular to reversible temperature-sensitive ink and a preparation method and application thereof.

Background

With the continuous development of economy, the number of counterfeit products is continuously increased, so that the anti-counterfeiting of the products is more and more important, and in the current commercial field, enterprises usually attach anti-counterfeiting marks to the products of the enterprises to prevent counterfeiting in order to avoid the counterfeiting of commodities. The ink anti-counterfeiting method is a widely used anti-counterfeiting mode at present, namely, special printing ink is prepared by adding special anti-counterfeiting materials into an ink binder and processing the materials through a special process. The anti-counterfeiting method is mainly used for trademarks and packages of products, and the anti-counterfeiting technology is simple, low in cost and easy to detect.

In order to further improve the anti-counterfeiting strength, the thermochromic display is one of the anti-counterfeiting marks commonly used in the market at present, the thermochromic anti-counterfeiting technology means that the anti-counterfeiting package can change color when meeting the temperature reaching the color change value, and the change can be classified into recoverable and non-recoverable according to the difference of the structures of thermochromic materials. The most advantage of this anti-fake technology is that it has good concealment and at the same time, because its identification method is simple, it has good effect for two-line anti-fake. At present, the thermochromic ink is insensitive to color change, has long color restoration time, cannot realize rapid color change, and influences the anti-counterfeiting effect.

Disclosure of Invention

The invention aims to provide reversible thermochromic ink aiming at the defects in the prior art, the thermochromic material is added into the reversible thermochromic ink to enable the ink to have an anti-counterfeiting function, the identification method is convenient and quick, and the color change effect is reversible.

The invention also aims to provide a preparation method of the reversible thermochromic ink.

The invention also aims to provide the application of the reversible thermochromic ink in lithographic printing.

The purpose of the invention is realized by the following technical scheme:

the reversible thermochromic ink is composed of the following raw materials in percentage by mass: thermochromic powder: 20-30% of modified malic acid resin: 20-30%, deionized water 5-10%, isopropanol: 40-50% and ethyl acetate: 5-8%, 1-3% of a dispersant, and a defoaming agent: 1-2%; the thermochromic powder is prepared from crystal violet lactone, boric acid and hexadecanol.

Preferably, the raw materials are as follows by mass percent: thermochromic powder: 20-25% of modified apple resin: 25-30% and deionized water: 5-8% of isopropanol: 40-50% and ethyl acetate: 5% -8%, dispersant: 1-3% of defoaming agent and 1-2% of defoaming agent.

Further, the dispersant is an SRE-4190 hyperdispersant.

Further, the antifoaming agent is 2-ethylhexanol.

Further, the mass ratio of crystal violet lactone, boric acid and hexadecanol in the thermochromic powder is 1-5: 15-20: 45-50.

Preferably, the mass ratio of crystal violet lactone, boric acid and cetyl alcohol in the thermochromic powder is 1:15: 50.

The invention takes crystal violet lactone as a color former and boric acid as a color developing agent to prepare the thermochromic material, thereby endowing the ink with a thermochromic effect and realizing the anti-counterfeiting function of the ink; the components of the thermochromic powder are scientifically and reasonably designed, and the color change sensitivity of the reversible thermochromic ink is improved.

The preparation method of the reversible thermochromic ink comprises the following steps:

s1, preparing thermochromic powder: mixing crystal violet lactone, boric acid and hexadecanol, heating in water bath, cooling and drying after the reaction is finished, and grinding to obtain thermochromic powder;

s2, preparing a solvent: adding the modified malic acid resin into isopropanol and deionized water, fully stirring for dissolving, adding ethyl acetate and part of defoaming agent, and uniformly stirring;

s3, primary stirring: placing the thermochromic powder prepared in step S1 into the solution in step S2, and performing primary stirring;

s4, secondary stirring: and (4) adding a dispersing agent and the rest defoaming agent into the mixed solution stirred in the step (S3), and stirring for the second time to obtain the reversible thermochromic ink.

Further, the water bath heating temperature in the step S1 is 80-95 ℃, and the reaction time is 3-5 h.

Further, the temperature of the drying process in the step S1 is 40 ℃, and the time is 5-6 h.

Further, the fineness of the thermochromic powder in step S1 is 700-800 μm.

Further, the process parameters of the primary stirring in step S3 are as follows: the stirring speed is 1000-1200 r/min, and the stirring time is 4-5 h.

Further, the process parameters of the secondary stirring in step S4 are as follows: the stirring speed is 600-800 r/min, and the stirring time is 3-5 h.

Further, the addition amount of the antifoaming agent in steps S2 and S4 is not more than 1%

The application of the reversible thermochromic ink in lithographic printing is provided.

Compared with the prior art, the invention has the following beneficial effects:

the thermochromic powder is added into the ink, so that the reversible thermochromic ink also has the property of color change when being heated, and the anti-counterfeiting effect is achieved. In the preparation process, the thermochromic effect of the ink is improved by adjusting the components of the thermochromic material in the reversible thermochromic ink.

The reversible thermochromic ink is prepared by adopting an ink anti-counterfeiting technology and using thermochromic powder synthesized from crystal violet lactone, boric acid and hexadecanol, compared with the existing thermochromic material, the thermochromic ink has higher color change sensitivity, the whole color change process can be completed within 3-4 ℃, and the color restoration time is shortened to only 10-12 seconds. Meanwhile, the content of the thermochromic material is changed, and the thermochromic effect is adjusted, so that the thermochromic ink is light blue at normal temperature and is grey white at the temperature of 48-52 ℃. When in use, the color of the printed graph and text can be changed by a certain heat source, and the color can be recovered after the heat source is removed for a period of time. The identification method is convenient and rapid, and has reversibility.

According to the reversible thermochromic ink, the defoaming agent and the dispersing agent are added into the reversible thermochromic ink, and the thermochromic powder is uniformly dispersed in the ink. Prevents the ink from generating foam in the preparation and use processes and influencing the thermochromic performance of the reversible thermochromic ink. The dispersing agent can effectively improve the precipitation problem of the thermochromic powder after standing, and the dispersibility of the thermochromic powder in the ink is kept stable.

Drawings

FIG. 1 is a graph showing the effect of a printed sample obtained in example 1 at normal temperature;

FIG. 2 is a graph showing the effect of the printed pattern obtained in example 1 in a thermostat at 48 ℃.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following specific examples.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1

The embodiment provides a preparation method of reversible thermochromic ink, which comprises the following raw material components: thermochromic powder: 23% of modified malic acid resin: 22% and deionized water: 5%, isopropyl alcohol: 40%, ethyl acetate: 5%, SRE-4190 hyperdispersant: 3%, 2-ethylhexanol: 2 percent; the preparation method comprises the following specific steps:

s1, preparing thermochromic powder: mixing crystal violet lactone, boric acid and hexadecanol according to a mass ratio of 1:15:50, stirring by using a magnetic stirrer, uniformly stirring, putting into a water bath kettle at 80 ℃ for reaction for 3 hours, drying in a constant-temperature drying box at 40 ℃ after the reaction is finished, and sieving after ball milling to obtain thermochromic powder with the fineness of 800 mu m;

s2, preparing a solvent: adding the modified malic acid resin into isopropanol and deionized water, fully stirring and dissolving, adding half of 2-ethylhexanol, and uniformly stirring;

s3, primary stirring: placing the thermochromic powder prepared in the step (S2) into the solution in the step (S2), and stirring for one time at the stirring speed of 1000r/min for 4 h;

s4, secondary stirring: and (5) adding the SRE-4190 hyperdispersant and the rest 2-ethylhexanol into the mixed solution stirred in the step S3, and stirring for the second time at the stirring speed of 800r/min for 5 hours to obtain the reversible thermochromic ink.

Example 2

The embodiment provides a preparation method of reversible thermochromic ink, which comprises the following raw material components: thermochromic powder: 20% of modified malic acid resin: 24% and deionized water: 8%, isopropyl alcohol: 40%, ethyl acetate: 6%, SRE-4190 hyperdispersant: 1%, 2-ethylhexanol: 1 percent; the preparation method comprises the following specific steps:

s1, preparing thermochromic powder: mixing crystal violet lactone, boric acid and hexadecanol according to a mass ratio of 5:20:45, stirring by using a magnetic stirrer, uniformly stirring, putting into a 95 ℃ water bath kettle for reaction for 4 hours, drying in a 40 ℃ constant-temperature drying box after the reaction is finished, and sieving after ball milling to obtain thermochromic powder with the fineness of 700 mu m;

s2, preparing a solvent: adding the modified malic acid resin into isopropanol and deionized water, fully stirring and dissolving, adding ethyl acetate and 0.5% 2-ethylhexanol, and uniformly stirring;

s3, primary stirring: placing the thermochromic powder prepared in the step (S2) into the solution in the step (S2), and stirring for one time at the stirring speed of 1100r/min for 5 h;

s4, secondary stirring: and (3) adding the SRE-4190 hyperdispersant and the rest 2-ethylhexanol into the mixed solution stirred in the step S3, and stirring for the second time at the stirring speed of 600r/min for 3 hours to obtain the reversible thermochromic ink.

Example 3

The embodiment provides a preparation method of reversible thermochromic ink, which comprises the following raw material components: thermochromic powder: 20% of modified malic acid resin: 20% and deionized water: 4%, isopropyl alcohol: 45%, ethyl acetate: 7%, SRE-4190 hyperdispersant: 2%, 2-ethylhexanol: 2 percent; the preparation method comprises the following specific steps:

s1, preparing thermochromic powder: mixing crystal violet lactone, boric acid and hexadecanol according to a mass ratio of 1:20:50, stirring by using a magnetic stirrer, uniformly stirring, putting into a 90 ℃ water bath kettle for reaction for 5 hours, drying in a 40 ℃ constant-temperature drying box after the reaction is finished, and sieving after ball milling to obtain thermochromic powder with the fineness of 700 mu m;

s2, preparing a solvent: adding the modified malic acid resin into isopropanol, fully stirring and dissolving, adding half of 2-ethylhexanol, and uniformly stirring;

s3, primary stirring: placing the thermochromic powder prepared in the step (S2) into the solution in the step (S2), and stirring for one time at the stirring speed of 1200r/min for 5 h;

s4, secondary stirring: and (4) adding the SRE-4190 hyperdispersant and the rest 2-ethylhexanol into the mixed solution stirred in the step S3, and stirring for the second time at the stirring speed of 700r/min for 4 hours to obtain the reversible thermochromic ink.

Example 4

This example provides a method for preparing a reversible thermochromic ink, referring to example 1, which is different from example 1 in that the following raw material components are used: 29% of thermochromic material, modified malic acid resin: 20% and deionized water: 4%, isopropyl alcohol: 40%, ethyl acetate: 5%, SRE-4190 hyperdispersant: 1%, 2-ethylhexanol: 1 percent; the remaining process steps are the same as in example 1.

Example 5

This example provides a method for preparing a reversible thermochromic ink, referring to example 1, which is different from example 1 in that the following raw material components are used: thermochromic materials: 20% of modified malic acid resin: 20% and deionized water: 10%, isopropyl alcohol: 40%, ethyl acetate: 5%, SRE-4190 hyperdispersant: 3%, 2-ethylhexanol: 2 percent; the remaining process steps are the same as in example 1.

Comparative example 1

This comparative example provides a method for preparing a reversible thermochromic ink, referring to example 1, which is different from example 1 in that the thermochromic powder contains crystal violet lactone, boric acid and cetyl alcohol in a mass ratio of 10:25: 60.

Comparative example 2

This comparative example provides a method for preparing a reversible thermochromic ink, referring to example 1, which is different from example 1 in that the thermochromic powder contains crystal violet lactone, boric acid and cetyl alcohol in a mass ratio of 10:10: 30.

The reversible thermochromic inks prepared in examples 1-5 and comparative examples 1-2 were used in an IGT printability tester, with a printing pressure of 500N and an ink amount of 0.5ml in an ink injector, and printed samples were obtained.

Respectively standing the printing sample in constant temperature boxes at room temperature and 48 ℃, and observing the color of the reversible thermochromic ink at room temperature and the color change effect in the constant temperature box, wherein as shown in figures 1 and 2, the printing sample of the reversible thermochromic ink in example 1 is light blue at room temperature and is grey white in a constant temperature box at 48 ℃; the printed sample was removed from the oven and returned to a pale blue color after 10S.

A printing sample obtained by printing the reversible thermochromic ink prepared in the embodiments 1-5 of the invention has high color change sensitivity, the color change temperature is 48-52 ℃, and the color restoration time is 10-12 seconds. In the test process, the color change temperature of the ink of the comparative example 1 ranges from 45 ℃ to 58 ℃, and the color restoration time is 22S; the color change temperature range of the ink of the comparative example 2 is 50-62 ℃, and the color restoration time is 25S; the color change sensitivity of examples 1-5 is significantly better than that of comparative examples 1 and 2.

It should be understood that the above examples are only for clearly illustrating the technical solutions of the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. a reversible thermochromic ink, is characterized in that, is made up of the raw material of following mass percentage: thermochromic powder: 20～30%, modified malic acid resin: 20～30%, deionized water 5～10% , isopropanol: 40~50%, ethyl acetate: 5%~8%, dispersant 1~3%, defoamer: 1~2%; the thermochromic powder is composed of crystal violet lactone, boric acid and prepared from hexadecanol.

2. reversible thermochromic ink according to claim 1, is characterized in that, the mass percentage of described raw material is as follows: thermochromic powder: 20～25%, modified apple resin: 25～30%, deionized water : 5~8%, isopropyl alcohol: 40~50%, ethyl acetate: 5%~8%, dispersant: 1~3%, defoamer: 1~2%.

3 . The reversible thermochromic ink according to claim 1 , wherein the dispersant is SRE-4190 hyperdispersant. 4 .

4. The reversible thermochromic ink according to claim 1, wherein the defoamer is 2-ethylhexanol.

5. The reversible thermochromic ink according to claim 1, wherein the mass ratio of crystal violet lactone, boric acid and cetyl alcohol in the thermochromic powder is 1～5:15～20:45～ 50.

6 . The reversible thermochromic ink according to claim 5 , wherein the mass ratio of crystal violet lactone, boric acid and cetyl alcohol in the thermochromic powder is 1:15:50. 7 .

7. the preparation method of the reversible thermochromic ink described in any one of claim 1～6, is characterized in that, comprises the following steps:

S1. Preparation of thermochromic powder: mixing crystal violet lactone, boric acid and cetyl alcohol, heating in a water bath, cooling and drying after completion of the reaction, and grinding to obtain thermochromic powder;

S2. Preparation of solvent: adding the modified malic acid resin to isopropanol and deionized water, fully stirring and dissolving, adding ethyl acetate and part of the defoamer and stirring evenly;

S3. One-time stirring: put the thermochromic powder prepared in step S1 into the solution in step S2, and perform one-time stirring;

S4. Secondary stirring: adding dispersant and remaining defoamer to the mixing and dissolving after stirring in step S3, and obtaining reversible thermochromic ink after secondary stirring.

8 . The preparation method according to claim 7 , wherein the temperature of the water bath heating in step S1 is 80-95° C., and the reaction time is 3-5 h. 9 .

9 . The preparation method according to claim 7 , wherein the temperature of the drying process in step S1 is 40° C. and the time is 5-6 h. 10 .

10. Application of the reversible thermochromic ink according to any one of claims 1 to 6 in lithographic printing.