CN111976070A - A kind of invisible anti-counterfeiting seal and preparation method thereof - Google Patents

Abstract

The invention discloses an invisible anti-counterfeiting seal and a preparation method thereof, wherein the preparation method comprises the following steps: uniformly mixing polydimethylsiloxane and a curing agent, defoaming, taking out and flatly laying on a glass plate after bubbles completely disappear, defoaming for the second time, and pouring into a mold for curing and molding to obtain a patch; cleaning and drying the patch, carrying out oxygen plasma treatment, soaking, washing and drying; printing a mask on the surface of the polydimethylsiloxane, performing laser etching, placing in a nitrogen atmosphere, introducing mixed gas, heating, cooling, taking out the seal, and cleaning to obtain the invisible anti-counterfeiting seal. The invention also comprises the invisible anti-counterfeiting seal manufactured by the method. The seal of the invention mainly realizes transfer printing through hydrophilic/hydrophobic intervals on the surface, and the surface of the seal is a whole smooth and uniform plane, so that the seal cannot be imitated through photos, thereby achieving the anti-counterfeiting effect.

Description

A kind of invisible anti-counterfeiting seal and preparation method thereof

technical field

The invention relates to the technical field of seal preparation, in particular to an invisible anti-counterfeiting seal and a preparation method thereof.

Background technique

In my country, the seal is a tool often used in people's work and life, including the use of the seal in the work, operation or operation of the government or enterprise. Seals have legal effect and are very important certificates for individuals, enterprises or governments. Therefore, criminals often make fake seals for profit, which also causes very serious social impact and economic losses. Therefore, it is very important to realize the anti-counterfeiting of the seal.

At present, the anti-counterfeiting strategy of seals mainly includes three aspects: (1) The anti-counterfeiting number, namely the anti-counterfeiting code, the first few digits of this number are the unified number of the seal management unit, and the last few digits are the serial number of the seal engraving company. Uniqueness and queryability; (2) Anti-counterfeiting font, the font of the seal is a professional anti-counterfeiting font, which is difficult to be imitated; (3) The anti-counterfeiting line of the seal, that is, there are some irregular graphics on the edge of the seal or on the font. The white notch makes it difficult to prevent counterfeiting.

However, the above traditional anti-counterfeiting methods can only achieve a certain degree of seal anti-counterfeiting. In the case of obtaining high-resolution photos of the surface of the seal, there is still a high probability that the seal can be forged. As a result, anti-counterfeiting methods of implanting chips into seals have also emerged. However, even the chips may be copied or separated from the seal. In order to solve this problem, it is necessary to invent an "invisible" seal, that is, an invisible anti-counterfeiting seal.

SUMMARY OF THE INVENTION

In view of the above deficiencies in the prior art, the present invention provides an invisible anti-counterfeiting seal and a preparation method thereof. The invisible anti-counterfeiting seal mainly realizes transfer printing through the hydrophilic/hydrophobic interval on the surface, and the surface of the seal will be a whole piece The smooth and uniform plane can not be imitated by photos, so as to achieve the effect of anti-counterfeiting, and the preparation method of the seal has a simple process and a short time required, which effectively solves the problems of easy forgery of the seal.

In order to achieve the above purpose, the technical solution adopted by the present invention to solve the technical problem is: a preparation method of an invisible anti-counterfeiting seal is provided, which comprises the following steps in turn:

(1) Patch preparation: Mix the polydimethylsiloxane and curing agent in a mass ratio of 2 to 10:1, then put them into a vacuum drying oven for deaeration for 1 to 2 hours. After the bubbles disappear completely, take them out and flatten them. Spread it on a glass plate, defoaming the second time for 20-40 minutes, then pour it into a mold, and cure it at a temperature of 60-75 °C for 2-4 hours to obtain a patch;

(2) Oxygen plasma treatment: the patch obtained in step (1) is cleaned and blown dry, then treated with oxygen plasma for 30-60s, and then placed in 0.4-0.6wt% sodium dodecyl sulfate solution to soak for 20-40s , and finally washed and dried in sequence to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during the oxygen plasma treatment is 120-140W, and the oxygen flow rate is 150-160sccm;

(3) Grafting hydrophobic molecules: 3D printing a mask on the surface of the polydimethylsiloxane obtained in step (2) by using a water-soluble polymer, and then placing it in a nitrogen atmosphere, introducing a mixed gas, at 60-80 °C Heating for 60-120min, cooling to room temperature, taking out the seal, and finally washing it with deionized water for 2-4 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: heating the hydrophobic molecules to a gaseous state, and then mixing with nitrogen gas by volume Mix at a ratio of 1:1 to get a mixed gas.

Further, the viscosity of the polydimethylsiloxane is 10 to 2000 mPa.s.

Further, the curing agent is Dow Corning 184 curing agent, ethyl orthosilicate or tin dibutyl cinnamate.

Further, in step (2), the patch is ultrasonically cleaned for 1-2 times with deionized water, acetone and anhydrous ethanol in sequence, and dried with compressed air.

Further, in step (2), finally rinse with deionized water for 20-40s, and blow dry with nitrogen.

Further, the gas flow rate of the mixed gas is 0.1 to 0.2 L/min.

Further, the hydrophobic molecule is trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane, trimethoxy (1H, 1H, 2H, 2H-nonafluorohexyl) silane or trimethoxy (1H, 1H , 2H, 2H-tridecafluoro-n-octyl) silane.

Further, the water-soluble polymer is polyethyleneimine, polyacrylamide or methoxy-terminated polyethylene glycol.

The invisible anti-counterfeiting seal obtained by the above-mentioned preparation method of the invisible anti-counterfeiting seal.

To sum up, the present invention has the following advantages:

1. The invisible anti-counterfeiting seal of the present invention mainly realizes the transfer through the hydrophilic/hydrophobic interval on the surface, and the surface of the seal will be a whole smooth and uniform plane, and the imitation of the seal cannot be realized by photos, so as to achieve anti-counterfeiting. The preparation method has the advantages of simple process and short required time, and effectively solves the problems of easy forgery of seals and the like.

2. In preparation, polydimethylsiloxane is used as the raw material, and the seal surface patch is prepared by cross-linking with the curing agent. The hardness is also different, and stamps with different feel can be made; then the patch is treated with oxygen plasma to make the whole patch become super-hydrophilic, and the surface contains a lot of -OH, so that the polydimethylsiloxane surface reaches a good hydrophilic and without cracks. In the preparation of the seal, no traditional engraving process is used. First, stick the mask that fits the surface of the stamp patch on the stamp surface, and then cut off the excess part of the mask by laser etching to complete the lettering; then place the stamp patch with the mask in the reaction chamber , by chemical vapor deposition (CVD), hydrophobic molecules (such as trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane, etc.) are grafted on the surface of the stamp patch, and then the mask is removed. Drop to complete the stamp preparation. The preparation process is simple and easy to control, can quickly prepare an invisible anti-counterfeiting seal, and improve the preparation efficiency of the seal.

3. There are two purposes of choosing water-soluble polymers when printing masks. First, after oxygen plasma treatment, the surface of the material is hydrophilic, and the use of water-soluble polymers has better compatibility with the surface and stronger adhesion. ; Second, in the process of removing the mask in the last step, it can be removed directly by the operation of water washing, which is convenient for removal. The invention utilizes the hydrophilic and hydrophobic effects of the material to achieve smooth and invisible surface. After the material contacts the ink or printing oil, the transfer of a specific pattern can be completed, and the invisible anti-counterfeiting of the seal is realized, which is difficult to imitate and forge.

Description of drawings

Figure 1 is a schematic diagram of the preparation process of the invisible anti-counterfeiting seal.

Detailed ways

Example 1

An invisible anti-counterfeiting seal, the preparation method of which comprises the following steps in turn:

(1) Patch preparation: Mix the polydimethylsiloxane and Dow Corning 184 curing agent in a mass ratio of 2:1, then put it into a vacuum drying oven for deaeration for 1 hour, take it out after the bubbles completely disappear, and spread it on the On the glass plate, defoamed for 20 minutes for a second time, then poured into the mold, and cured at 60 °C for 2 hours to obtain a patch;

(2) Oxygen plasma treatment: the patch obtained in step (1) was ultrasonically cleaned twice in sequence with deionized water, acetone and anhydrous ethanol, dried with compressed air, and then treated with oxygen plasma for 30s, and then put into 0.5wt% Soak in sodium dodecyl sulfate solution for 20s, finally rinse with deionized water for 20s, and blow dry with nitrogen to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during oxygen plasma treatment is 120W, and the oxygen flow rate is 150sccm;

(3) Grafting hydrophobic molecules: Polyethyleneimine was used to 3D print the mask on the surface of the polydimethylsiloxane obtained in step (2), then placed in a nitrogen atmosphere, a mixed gas was introduced, and heated at 60°C for 120min , after cooling to room temperature, take out the seal, and finally wash it with deionized water 3 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) ) silane is heated to a gaseous state, and then mixed with nitrogen in a volume ratio of 1:1 to obtain a mixed gas; the flow rate of the mixed gas is 0.1 L/min.

Example 2

An invisible anti-counterfeiting seal, the preparation method of which comprises the following steps in turn:

(1) Patch preparation: Mix the polydimethylsiloxane and Dow Corning 184 curing agent in a mass ratio of 4:1, and then put it into a vacuum drying oven for deaeration for 2 hours. After the bubbles completely disappear, take it out and spread it on a flat surface. On the glass plate, the second defoaming is performed for 20-40 minutes, then poured into the mold, and cured for 3 hours at a temperature of 70 °C to obtain a patch;

(2) Oxygen plasma treatment: the patch obtained in step (1) was ultrasonically cleaned twice in sequence with deionized water, acetone and anhydrous ethanol, dried with compressed air, and then treated with oxygen plasma for 40s, and then put into 0.5wt% Soak in sodium dodecyl sulfate solution for 30s, finally rinse with deionized water for 30s, and blow dry with nitrogen to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during oxygen plasma treatment is 130W, and the oxygen flow rate is 155sccm;

(3) Grafting hydrophobic molecules: 3D printing a mask on the surface of polydimethylsiloxane using methoxy-terminated polyethylene glycol, then placing it in a nitrogen atmosphere, passing a mixed gas, and heating at 70 °C for 100 min , take out the seal after cooling to room temperature, and finally wash it with deionized water 3 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: trimethoxy (1H, 1H, 2H, 2H-nonafluorohexyl) silane It is heated to a gaseous state, and then mixed with nitrogen in a volume ratio of 1:1 to obtain a mixed gas; the flow rate of the mixed gas is 0.2L/min.

Example 3

An invisible anti-counterfeiting seal, the preparation method of which comprises the following steps in turn:

(1) Patch preparation: Mix the polydimethylsiloxane and Dow Corning 184 curing agent in a mass ratio of 6:1, then put it into a vacuum drying oven for deaeration for 2 hours, take it out after the bubbles completely disappear, and spread it on the On the glass plate, defoamed for 30 minutes for the second time, poured into the mold, and cured at 70 °C for 3 hours to obtain a patch;

(2) Oxygen plasma treatment: the patch obtained in step (1) was ultrasonically cleaned twice in sequence with deionized water, acetone and anhydrous ethanol, dried with compressed air, and then treated with oxygen plasma for 40s, and then put into 0.5wt% Soak in sodium dodecyl sulfate solution for 30s, finally rinse with deionized water for 30s, and blow dry with nitrogen to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during oxygen plasma treatment is 130W, and the oxygen flow rate is 155sccm;

(3) Grafting hydrophobic molecules: Polyethyleneimine was used to 3D print the mask on the surface of the polydimethylsiloxane obtained in step (2), then placed in a nitrogen atmosphere, a mixed gas was introduced, and heated at 80°C for 80min , take out the seal after cooling to room temperature, and finally wash it with deionized water 3 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: base) silane is heated to a gaseous state, and then mixed with nitrogen in a volume ratio of 1:1 to obtain a mixed gas; the flow rate of the mixed gas is 0.1 L/min.

Example 4

An invisible anti-counterfeiting seal, the preparation method of which comprises the following steps in turn:

(1) Patch preparation: Mix polydimethylsiloxane and Dow Corning 184 curing agent in a mass ratio of 8:1, then put it into a vacuum drying oven for deaeration for 2 hours, take it out after the bubbles completely disappear, and spread it on the On the glass plate, defoamed for 30 minutes for a second time, poured into the mold, and cured at 75 °C for 3 hours to obtain a patch;

(2) Oxygen plasma treatment: the patch obtained in step (1) was ultrasonically cleaned once in turn with deionized water, acetone and anhydrous ethanol, dried with compressed air, and then treated with oxygen plasma for 50s, and then put into 0.5wt% Soak in sodium dodecyl sulfate solution for 30s, finally rinse with deionized water for 30s, and blow dry with nitrogen to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during oxygen plasma treatment is 130W, and the oxygen flow rate is 158sccm;

(3) Grafting hydrophobic molecules: 3D printing a mask on the surface of the polydimethylsiloxane obtained in step (2) by using methoxy-terminated polyethylene glycol, and then placing it in a nitrogen atmosphere, introducing a mixed gas, and placing it in a nitrogen atmosphere. Heating at 80°C for 60min, cooling to room temperature, take out the seal, and finally wash it with deionized water 3 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: trimethoxy (1H, 1H, 2H, 2H- Heptadecafluorodecyl)silane is heated to a gaseous state, and then mixed with nitrogen in a volume ratio of 1:1 to obtain a mixed gas; the flow rate of the mixed gas is 0.2 L/min.

Example 5

An invisible anti-counterfeiting seal, the preparation method of which comprises the following steps in turn:

(1) Patch preparation: Mix the polydimethylsiloxane and Dow Corning 184 curing agent in a mass ratio of 10:1, and then put it into a vacuum drying oven for deaeration for 2 hours. After the bubbles completely disappear, take it out and spread it on a flat surface. On the glass plate, defoamed for 40 minutes for a second time, poured into the mold, and cured at 75 °C for 4 hours to obtain a patch;

(2) Oxygen plasma treatment: the patch obtained in step (1) was ultrasonically cleaned twice in turn with deionized water, acetone and absolute ethanol, dried with compressed air, and then treated with oxygen plasma for 60s, and then put into 0.6wt% Soak in sodium dodecyl sulfate solution for 40s, finally rinse with deionized water for 40s, and blow dry with nitrogen to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during oxygen plasma treatment is 140W, and the oxygen flow rate is 160sccm;

(3) Grafting hydrophobic molecules: use polyacrylamide to 3D print the mask on the surface of the polydimethylsiloxane obtained in step (2), then place it in a nitrogen atmosphere, pass in a mixed gas, and heat it at 80 °C for 80 minutes, After cooling to room temperature, take out the seal, and finally wash it with deionized water 4 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: heating trimethoxy (1H, 1H, 2H, 2H-nonafluorohexyl) silane to a gaseous state, and then mixed with nitrogen in a volume ratio of 1:1 to obtain a mixed gas; the flow rate of the mixed gas is 0.2L/min.

Although the specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, they should not be construed as limiting the protection scope of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative efforts still belong to the protection scope of this patent.

Claims (9)

1. a preparation method of invisible anti-counterfeiting seal, is characterized in that, comprises the following steps successively: (1) Patch preparation: Mix the polydimethylsiloxane and curing agent in a mass ratio of 2 to 10:1, then put them into a vacuum drying oven for deaeration for 1 to 2 hours. After the bubbles disappear completely, take them out and flatten them. Spread it on a glass plate, defoaming the second time for 20-40 minutes, then pour it into a mold, and cure it at a temperature of 60-75 °C for 2-4 hours to obtain a patch; (2) Oxygen plasma treatment: the patch obtained in step (1) is cleaned and blown dry, then treated with oxygen plasma for 30-60s, and then placed in 0.4-0.6wt% sodium dodecyl sulfate solution to soak for 20-40s , and finally washed and dried in sequence to obtain the surface of polydimethylsiloxane; wherein, the radio frequency power during the oxygen plasma treatment is 120-140W, and the oxygen flow rate is 150-160sccm; (3) Grafting hydrophobic molecules: 3D printing a mask on the surface of the polydimethylsiloxane obtained in step (2) by using a water-soluble polymer, and then placing it in a nitrogen atmosphere, introducing a mixed gas, at 60-80 °C Heating for 60-120min, cooling to room temperature, taking out the seal, and finally washing with deionized water for 2-4 times to obtain an invisible anti-counterfeiting seal; wherein, the mixed gas is prepared by the following method: heating hydrophobic molecules to a gaseous state, then mixing with nitrogen Mix according to the volume ratio of 1:1 to obtain a mixed gas. 2 . The method for preparing an invisible anti-counterfeiting seal according to claim 1 , wherein the viscosity of the polydimethylsiloxane is 10-2000 mPa.s. 3 . 3. The preparation method of the invisible anti-counterfeiting seal as claimed in claim 1, wherein the curing agent is Dow Corning 184 curing agent, ethyl orthosilicate or dibutyltin cinnamate. 4. The preparation method of an invisible anti-counterfeiting seal as claimed in claim 1, wherein in step (2), the patch is ultrasonically cleaned in deionized water, acetone and absolute ethanol for 1 to 2 times successively, and dried with compressed air. . 5 . The method for preparing an invisible anti-counterfeiting seal according to claim 1 , wherein in step (2), rinse with deionized water for 20-40 s and dry with nitrogen. 6 . 6 . The method for preparing an invisible anti-counterfeiting seal according to claim 1 , wherein the gas flow rate of the mixed gas is 0.1-0.2 L/min. 7 . 7. The preparation method of invisible anti-counterfeiting seal as claimed in claim 1, wherein the hydrophobic molecule is trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane, trimethoxy (1H ,1H,2H,2H-nonafluorohexyl)silane or trimethoxy(1H,1H,2H,2H-tridecafluoro-n-octyl)silane. 8 . The method for preparing an invisible anti-counterfeiting seal according to claim 1 , wherein the water-soluble polymer is polyethyleneimine, polyacrylamide or methoxy-terminated polyethylene glycol. 9 . 9. The invisible anti-counterfeiting seal prepared by the method for preparing the invisible anti-counterfeiting seal according to any one of claims 1 to 8.

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