CN112376318B

CN112376318B - Anti-counterfeiting coating, anti-counterfeiting label printing process and anti-counterfeiting label

Info

Publication number: CN112376318B
Application number: CN202011293543.9A
Authority: CN
Inventors: 顾锦源
Original assignee: Wuxi Haiboyuan Packaging Technology Co ltd
Current assignee: Wuxi Haiboyuan Packaging Technology Co ltd
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2022-10-21
Anticipated expiration: 2040-11-18
Also published as: CN112376318A

Abstract

The application relates to the field of labels, and particularly discloses an anti-counterfeiting coating, an anti-counterfeiting label printing process and an anti-counterfeiting label. The anti-counterfeiting coating is prepared from the following raw materials in parts by mass: 100-200 parts of modified starch prepolymer and 1-2 parts of diaryl iodonium salt, wherein the modified starch prepolymer is prepared by grafting oxidized starch with graphene oxide and then crosslinking with polyvinyl alcohol; the preparation method comprises the following steps: weighing the modified starch prepolymer and the diaryl iodonium salt according to the formula ratio, and stirring and blending to obtain the anti-counterfeiting coating. The anti-counterfeiting coating is environment-friendly, the coating adhesive strength formed after the anti-counterfeiting coating is cured is high, the toughness is good, the curing time is short, and the printing quality is good. In addition, the anti-counterfeit label of this application can be used to anti-fake, and it has green, the better advantage of printing quality.

Description

Anti-counterfeiting coating, anti-counterfeiting label printing process and anti-counterfeiting label

Technical Field

The application relates to the field of labels, in particular to an anti-counterfeiting coating, an anti-counterfeiting label printing process and an anti-counterfeiting label.

Background

The anti-counterfeiting label is one of products of anti-counterfeiting technologies, wherein the coded anti-counterfeiting technology is to print special codes such as anti-counterfeiting codes, two-dimensional codes and bar codes on label paper, identity information represented by the special codes is recorded in an anti-counterfeiting code database, and a consumer inquires about a certain anti-counterfeiting code to obtain product information adhered with the anti-counterfeiting label.

At present, the anti-counterfeiting label is implemented by a coding anti-counterfeiting technology, and the anti-counterfeiting modes mainly comprise two types: the first is that the anti-counterfeiting code is printed on the front surface of the label paper, a film covering film and an opaque coating are sequentially arranged above the anti-counterfeiting code, and a consumer can inquire the anti-counterfeiting code by scratching off the coating; the second is to print anti-fake code at the label paper back, and anti-fake code below is equipped with membrane and adhesive layer in proper order, and label paper passes through the adhesive layer and bonds on the object surface, and the consumer tears label paper and can inquire anti-fake code. The coating film is formed by curing a varnish, UV varnish or other coating.

The use method of the opaque coating for anti-counterfeiting comprises the following steps: the anti-counterfeiting coating is printed above the anti-counterfeiting code through screen printing, and the ultraviolet lamp illuminator is cured, so that the anti-counterfeiting coating is firmly attached to the surface of the light-coated film, and an opaque coating is formed after the anti-counterfeiting coating is cured.

Common anti-counterfeiting coating comprises polyurethane prepolymer, substances such as curing agent and pigment, contain a large amount of polyisocyanate in anti-counterfeiting coating's the polyurethane prepolymer, polyurethane prepolymer's VOC volatile is great, and anti-counterfeiting coating is in order to have the hiding power, contain heavy metal ion like lead in the pigment that adds, chromium etc., be heavy metal pollutant, anti-counterfeiting coating does not have the feature of environmental protection, therefore, need seek the anti-counterfeiting coating of an environmental protection, and when making this coating be applied to the antifalsification label, it is firm to bond between the opaque coating of formation and the antifalsification label substrate.

Disclosure of Invention

The application provides an anti-counterfeiting coating, an anti-counterfeiting label printing process and an anti-counterfeiting label.

In a first aspect, the application provides an anti-counterfeiting coating, which adopts the following technical scheme:

100-200 parts of modified starch prepolymer

1-2 parts of diaryl iodonium salt

The modified starch prepolymer is prepared by the following steps:

s1, mixing oxidized starch with water, stirring and heating until the oxidized starch is dissolved, and preparing into oxidized starch milk with the concentration of 20-30 wt%; adding graphene oxide into oxidized starch milk, and performing ultrasonic dispersion, wherein the mass ratio of the graphene oxide to the oxidized starch is 1 (60-120), the ultrasonic frequency is 40-60Hz, and the ultrasonic time is 0.5-1.5h, so as to prepare modified starch milk;

s2, adding polyvinyl alcohol into distilled water, wherein the mass ratio of polyvinyl alcohol to oxidized starch is (0.14-0.24): 1, stirring and heating polyvinyl alcohol/water mixed solution until the polyvinyl alcohol is completely dissolved to obtain polyvinyl alcohol solution, and cooling the polyvinyl alcohol solution to 50-60 ℃ after the polyvinyl alcohol solution is kept warm for 10 min;

and S3, adding the polyvinyl alcohol solution into the modified starch milk, and uniformly stirring to obtain the modified starch prepolymer.

By adopting the technical scheme, the graphene oxide is used for carrying out first modification, so that oxidized starch is grafted on the graphene oxide, the polyvinyl alcohol is used for carrying out second modification, the polyvinyl alcohol is crosslinked with the oxidized starch, and the modified starch prepolymer has certain viscosity; before the anti-counterfeiting coating is used, weighing diaryl iodonium salt and modified starch prepolymer according to the formula amount, and uniformly stirring; after the anti-counterfeiting coating is printed, when ultraviolet light irradiates, the diaryl iodonium salt enables the modified starch prepolymer to be rapidly cured to form a regular net-shaped structure, meanwhile, the diaryl iodonium salt is photolyzed and is complexed with the modified starch prepolymer, and the complex is blue black and opaque, has covering performance and meets the requirement of serving as the anti-counterfeiting coating.

The anti-counterfeiting coating formed by the anti-counterfeiting coating prepared according to the proportion has the following advantages:

firstly, the components of the anti-counterfeiting coating are safe and non-toxic, and the oxidized starch and the polyvinyl alcohol are degradable materials, so that the anti-counterfeiting coating has the characteristics of environmental protection;

secondly, the oxidized starch, the oxidized graphene and the polyvinyl alcohol are mutually crosslinked to form a regular network structure, so that the anti-counterfeiting coating has good bonding strength;

thirdly, the modified starch prepolymer has certain viscosity and can be attached to the surface of the coated film, and the modified starch prepolymer is subjected to radiation crosslinking under ultraviolet light, so that the modified starch prepolymer can be quickly cured;

fourthly, as the modified starch prepolymer contains filler particles, such as a large amount of graphene oxide and a small amount of insoluble polyvinyl alcohol, which are filled in the network structure formed by the anti-counterfeiting coating, the shrinkage rate of the network structure formed by the anti-counterfeiting coating can be effectively reduced, and the breaking elongation of the anti-counterfeiting coating after curing is improved;

fifthly, on the basis of the formula, pigment components capable of playing a role in covering, such as organic environment-friendly pigments-phthalocyanine blue, naphthol red and the like, can be added, so that the covering power of the anti-counterfeiting coating is further enhanced, and anti-counterfeiting layers with different colors can be formed; the mass ratio of the blended pigment component to the modified starch prepolymer is (0-10): 1000 is preferred.

Preferably, the oxidized starch has a carboxyl content of 0.1 to 0.3 wt.%.

By adopting the technical scheme, the carboxyl content represents the oxidation degree, the higher the carboxyl content is, the deeper the oxidation degree is, the grafting rate of graphene oxide and the crosslinking rate of polyvinyl alcohol are favorably improved, but the carboxyl content of oxidized starch is too high, a macromolecular chain is broken, the regularity of a formed network structure is poor, the bonding strength of the anti-counterfeiting coating is reduced, and therefore, the bonding strength of the anti-counterfeiting coating is better within the range of the carboxyl content.

Preferably, the mass ratio of the graphene oxide to the oxidized starch is 1 (80-100).

By adopting the technical scheme, the amount of the graphene oxide is increased, the grafting rate is increased, the graphene oxide can also be used as a filler to improve the fracture elongation of the anti-counterfeiting coating, but when the amount of the graphene oxide is too large, the particle size formed by agglomeration of the graphene oxide is too large, the structural regularity of the anti-counterfeiting coating is reduced, and the bonding strength is reduced.

Preferably, the ultrasonic frequency of the graphene oxide in the step S1 is 50Hz, and the ultrasonic time is 1h.

By adopting the technical scheme, the grafting rate is increased as the ultrasonic time of the graphene oxide is longer, but the grafting rate of the graphene oxide is almost unchanged when the ultrasonic time and the ultrasonic frequency exceed a certain range.

Preferably, the mass ratio of the polyvinyl alcohol to the oxidized starch in the step S2 is (0.18-0.20): 1.

By adopting the technical scheme, the consumption of the polyvinyl alcohol is low, the viscosity of the modified starch prepolymer is reduced, the consumption of the polyvinyl alcohol is increased, the hydrogen bond association between the polyvinyl alcohol and the oxidized starch is increased, the crosslinking degree is increased, the viscosity of the modified starch prepolymer is increased, when the consumption of the polyvinyl alcohol is too large, the viscosity of the anti-counterfeiting coating is too high, the flowability is poor, and the curing time of the anti-counterfeiting coating is prolonged.

Preferably, the degree of alcoholysis of the polyvinyl alcohol is from 60% to 88%.

Through the technical scheme, the polyvinyl alcohol with higher alcoholysis degree has poorer hydrophilicity, the dispersity in the modified starch milk is reduced, the crosslinking rate with oxidized starch and the grafting rate with graphene oxide are both reduced, the bonding strength of the anti-counterfeiting coating is reduced, but the alcoholysis degree is too low, the anti-counterfeiting coating is not beneficial to radiation grafting with the graphene oxide, and the curing time of the anti-counterfeiting coating is longer.

Preferably, the polyvinyl alcohol solution added into the modified starch milk in the step S2 is stirred for 0.3-0.5h.

Through above-mentioned technical scheme, the churning time overlength, oxidized starch and polyvinyl alcohol crosslinking rate are higher for the viscosity increase of modified starch prepolymer, the mobility is relatively poor, is unfavorable for the later stage coating even, and the churning time is too short, and the crosslinking rate of polyvinyl alcohol is lower, easily slides on the membrane surface that covers, and the printing is inhomogeneous.

In a second aspect, the present application provides an anti-counterfeit label printing process, which adopts the following technical scheme:

an anti-counterfeit label printing process comprises a label pattern printing step, a laminating film printing step and an anti-counterfeit layer printing step;

wherein, the anti-counterfeiting layer printing step is:

and (3) performing screen printing on the paper base material treated by the laminating film printing step by using the anti-counterfeiting coating, and irradiating and curing by using an ultraviolet lamp to obtain the anti-counterfeiting layer for covering the label pattern.

Through adopting above-mentioned technical scheme, through ultraviolet lamp light irradiation, initiate anti-counterfeit coating solidification for anti-counterfeit coating can firmly be attached to the printing have the paper substrate of tectorial membrane, and solidification rate is very fast, and printing quality is better.

In a third aspect, the application provides an anti-counterfeit label using an anti-counterfeit coating, which adopts the following technical scheme:

an anti-counterfeit label is manufactured by the anti-counterfeit label printing process.

Through the technical scheme, the anti-counterfeit label prepared by the process has the advantages of environmental friendliness and high adhesive strength.

In summary, the present application has the following beneficial effects:

1. the anti-counterfeiting coating comprises modified starch prepolymer and an initiator, wherein the modified starch prepolymer is prepared from graphene oxide, polyvinyl alcohol and oxidized starch, the initiator is diaryl iodonium salt, the raw materials are non-toxic, and the polyvinyl alcohol and the oxidized starch are degradable materials and are relatively environment-friendly.

2. The anti-counterfeiting coating is characterized in that oxidized starch is utilized to graft graphene oxide and polyvinyl alcohol in sequence, the polyvinyl alcohol and the graphene oxide are crosslinked by virtue of the initiation of diaryl iodonium salt, and the oxidized starch, the graphene oxide and the polyvinyl alcohol react with each other to form a regular network structure.

3. The anti-counterfeit label prepared by the method has the advantages of environmental protection, high bonding strength and high toughness.

Detailed Description

Unless otherwise specified, the specifications and sources of the raw materials in the following preparation examples and examples are shown in table 1 below:

TABLE 1

Preparation example

Preparation example 1

A modified starch prepolymer is prepared by the following steps:

p1, weighing 15g of oxidized starch, wherein the carboxyl content of the oxidized starch is 0.05wt%, adding 75g of distilled water into the oxidized starch, stirring and mixing, heating to 40 ℃, completely dissolving the oxidized starch, and preparing into oxidized starch milk with the concentration of 20 wt%;

p2, weighing 0.25g of graphene oxide, adding the graphene oxide into oxidized starch milk, and performing ultrasonic dispersion at an ultrasonic frequency of 40Hz for 0.5h to obtain modified starch milk;

p3, weighing 2.1g of polyvinyl alcohol with 99% alcoholysis degree, and mixing the polyvinyl alcohol and the distilled water according to a mass ratio of 1:5, mixing, heating the polyvinyl alcohol/water mixed solution to 90 ℃, stirring and dissolving to obtain a polyvinyl alcohol solution, completely dissolving the polyvinyl alcohol solution, then preserving the temperature for 10min, and cooling to 50 ℃;

and adding the P4 and the polyvinyl alcohol solution into the modified starch milk, and stirring for 0.8h to prepare the modified starch prepolymer.

Preparation examples 2 to 4

A modified starch prepolymer is prepared on the basis of preparation example 1, and is different from preparation example 1 in that: the carboxyl content of the oxidized starch varied, as shown in Table 2.

TABLE 2 carboxyl content of oxidized starch

Preparation examples 5 to 8

A modified starch prepolymer is prepared on the basis of preparation example 3, and is different from preparation example 3 in that: the mass ratio of the graphene oxide to the oxidized starch is 1 (80-100), which is specifically shown in Table 3.

TABLE 3 Mass ratio of graphene oxide to oxidized starch

Preparation examples 9 to 12

A modified starch prepolymer is prepared on the basis of preparation example 6, and is different from preparation example 6 in that: the mass ratio of polyvinyl alcohol to oxidized starch was varied, as shown in Table 4 below.

TABLE 4 Mass ratio of polyvinyl alcohol to oxidized starch

Preparation examples 13 to 15

A modified starch prepolymer is prepared on the basis of preparation example 10, and is different from preparation example 10 in that: the degree of alcoholysis of polyvinyl alcohol was varied and is shown in Table 5.

TABLE 5 degree of alcoholysis of polyvinyl alcohol

Preparation examples 16 to 18

A modified starch prepolymer is prepared on the basis of preparation example 15, and is different from preparation example 15 in that: the stirring time in step P4 was varied and is specifically shown in Table 6.

TABLE 6 stirring time in step P4

Preparation examples 19 to 20

A modified starch prepolymer is prepared on the basis of preparation example 18, and is different from preparation example 18 in that: the quality of the distilled water contained in the oxidized starch milk obtained in the step P1 is different, and the concentration of the prepared oxidized starch milk is different, which is specifically shown in Table 7.

TABLE 7

Preparation examples 21 to 22

A modified starch prepolymer is prepared on the basis of preparation example 19, and is different from preparation example 19 in that: the ultrasonic frequency and the ultrasonic time of the graphene oxide in the oxidized starch milk in the step P2 are different, and are specifically shown in Table 8.

TABLE 8 ultrasonic frequency and ultrasonic time of graphene oxide in oxidized starch milk in step P2

Preparation example	Ultrasonic frequency (Hz)	Ultrasonic time (h)
			Preparation example 21	50	1
Preparation example 22	60	1.5

Preparation examples 23 to 24

A modified starch prepolymer prepared on the basis of preparation example 21 is different from preparation example 21 in that: the polyvinyl alcohol solutions had different cooling temperatures, as shown in table 9.

TABLE 9 temperature reduction of polyvinyl alcohol solution

Preparation example	Temperature lowering (. Degree.C.) of polyvinyl alcohol solution
		Preparation example 23	55
Preparation example 24	60

Examples are given.

Example 1

An anti-counterfeiting coating is prepared by the following steps:

100g of the modified starch prepolymer prepared in preparation example 1 and 1g of diaryliodonium salt were weighed and mixed by stirring.

Examples 2 to 24

An anti-counterfeiting coating is prepared on the basis of the embodiment 1, and is characterized in that: the sources of the modified starch prepolymers used were different and are shown in Table 10.

TABLE 10 sources of modified starch prepolymers used

Examples	Modified starch prepolymer	Examples	Modified starch prepolymer
				Example 2	Preparation example 2	Example 14	Preparation example 14
Example 3	Preparation example 3	Example 15	Preparation example 15
				Example 4	Preparation example 4	Example 16	Preparation example 16
Example 5	Preparation example 5	Example 17	Preparation example 17
				Example 6	Preparation example 6	Example 18	Preparation example 18
Example 7	Preparation example 7	Example 19	Preparation example 19
				Example 8	Preparation example 8	Example 20	Preparation example 20
Example 9	Preparation example 9	Example 21	Preparation example 21
				Example 10	Preparation example 10	Example 22	Preparation example 22
Example 11	Preparation example 11	Example 23	Preparation example 23
				Example 12	Preparation example 12	Example 24	Preparation example 24
Example 13	Preparation example 13

Examples 25 to 30

An anti-counterfeiting coating is prepared on the basis of example 23, and is different from example 23 in that: the formula amounts of the modified starch prepolymer and the diaryl iodonium salt are different, and are shown in table 11.

TABLE 11 formula amounts of modified starch prepolymer and diaryl iodonium salt

Examples	Modified starch prepolymer (g)	Diaryl iodonium salt (g)
			Example 25	150	1
Example 26	200	1
			Example 27	150	1.5
Example 28	150	2
			Example 29	200	1.5
Example 30	200	2

Example 31

An anti-counterfeiting coating is prepared on the basis of example 28, and is different from example 28 in that: phthalocyanine blue is also added into the anti-counterfeiting coating, and the mass ratio of the phthalocyanine blue to the modified starch prepolymer is 5:1000.

application example

Application example 1

An anti-counterfeit label is prepared by the following steps:

a1, printing a label pattern: conveying the paper base material to the lower part of the first silk screen plate, reciprocating a scraper, coating UV ink on the paper base material, conveying the paper base material to a lighting lamp, and irradiating for 30 seconds by using an ultraviolet lamp with electric power of 600W to obtain the paper base material printed with the anti-counterfeiting code;

a2, printing a laminating film: coating UV gloss oil on the surface of the paper base material printed with the anti-counterfeiting code, and irradiating the paper base material with an ultraviolet lamp with the electric power of 600W for 30s to obtain the paper base material printed with the coated film;

a3, printing of an anti-counterfeiting layer: the paper base material printed with the coated film is conveyed to the lower part of the second silk screen mesh plate, the scraper reciprocates, the paper base material coated with the coated film in the embodiment 1 is conveyed to a lighting lamp, and the paper base material is irradiated for 30s by an ultraviolet lamp with the electric power of 600W, so that the anti-counterfeiting label is prepared.

Application examples 2 to 31

An anti-counterfeit label is prepared on the basis of application example 1, and is different from application example 1 in that: the sources of the anti-counterfeiting coatings used were different, and are specifically shown in table 12 below.

TABLE 12 sources of anti-counterfeiting coating used

Application example	Anti-counterfeiting coating	Application example	Anti-counterfeiting coating
				Application example 2	Example 2	Application example 18	Example 18
Application example 3	Example 3	Application example 18	Example 18
				Application example 4	Example 4	Application example 19	Example 19
Application example 5	Example 5	Application example 20	Example 20
				Application example 6	Example 6	Application example 21	Example 21
Application example 7	Example 7	Application example 22	Example 22
				Application example 8	Example 8	Application example 23	Example 23
Application example 9	Example 9	Application example 24	Example 24
				Application example 10	Example 10	Application example 25	Example 18
Application example 11	Example 11	Application example 26	Example 19
				Application example 12	Example 12	Application example 27	Example 20
Application example 13	Example 13	Application example 28	Example 21
				Application example 14	Example 14	Application example 29	Example 22
Application example 15	Example 15	Application example 30	Example 23
				Application example 16	Example 16	Application example 31	Example 31

Comparative application example

Comparative application example 1

An anti-counterfeit label is prepared by the following steps:

(1) Weighing 15g of oxidized starch, wherein the carboxyl content of the oxidized starch is 0.05wt%, adding 75g of distilled water into the oxidized starch, stirring and mixing, heating to 40 ℃ to completely dissolve the oxidized starch, and preparing into oxidized starch milk with the concentration of 20 wt%;

(2) Weighing 2.1g of polyvinyl alcohol with alcoholysis degree of 99%, and mixing the polyvinyl alcohol and distilled water according to a mass ratio of 1:5, mixing, heating the polyvinyl alcohol/water mixed solution to 90 ℃, stirring and dissolving to obtain a polyvinyl alcohol solution, preserving the temperature for 10min after the polyvinyl alcohol solution is completely dissolved, cooling to 50 ℃, adding the polyvinyl alcohol solution into the modified starch milk, and stirring for 0.8h to obtain the modified starch adhesive;

(3) Weighing 0.25g of graphene oxide, adding the graphene oxide into oxidized starch milk, and performing ultrasonic dispersion at an ultrasonic frequency of 40Hz for 0.5h to obtain a modified starch prepolymer;

(4) Weighing 100g of the modified starch prepolymer and 1g of diaryl iodonium salt, stirring and blending to prepare the anti-counterfeiting coating;

(5) Printing a label pattern: conveying the paper base material to the lower part of the first silk screen plate, enabling a scraper to reciprocate, coating UV ink on the paper base material, conveying the paper base material to a lighting lamp, and irradiating for 30 seconds by using an ultraviolet lamp with electric power of 600W to obtain the paper base material printed with the anti-counterfeiting code;

(6) And (3) coating film printing: coating UV gloss oil on the surface of the paper base material printed with the anti-counterfeiting code, and irradiating the paper base material with an ultraviolet lamp with the electric power of 600W for 30s to obtain the paper base material printed with the coated film;

(7) Printing an anti-counterfeiting layer: and (5) conveying the paper base material printed with the coated film to the lower part of a second silk screen plate, reciprocating a scraper, coating the anti-counterfeiting coating prepared in the step (4) on the paper base material, conveying the paper base material to a lighting lamp, and irradiating the paper base material for 30 seconds by using an ultraviolet lamp with the electric power of 600W to prepare the anti-counterfeiting label.

Comparative application example 2

An anti-counterfeit label is prepared by the following steps:

(3) Weighing 100g of the modified starch adhesive and 1g of diaryl iodonium salt, stirring and blending to prepare the anti-counterfeiting coating;

(4) Printing a label pattern: conveying the paper base material to the lower part of the first silk screen plate, enabling a scraper to reciprocate, coating UV ink on the paper base material, conveying the paper base material to a lighting lamp, and irradiating for 30 seconds by using an ultraviolet lamp with electric power of 600W to obtain the paper base material printed with the anti-counterfeiting code;

(5) And (3) coating film printing: coating UV gloss oil on the surface of the paper base material printed with the anti-counterfeiting code, and irradiating the paper base material with an ultraviolet lamp with the electric power of 600W for 30s to obtain the paper base material printed with the coated film;

(6) Printing an anti-counterfeiting layer: and (3) conveying the paper base material printed with the coated film to the lower part of the second silk screen mesh plate, enabling a scraper to reciprocate, coating the anti-counterfeiting coating prepared in the step (3) on the paper base material, and baking for 2 hours at the temperature of 60 ℃ to prepare the anti-counterfeiting label.

Performance test

Detection method

The detection standard of the VOC content of the anti-counterfeiting coating is GB/T23985-2009;

the detection standard of the bonding strength of the anti-counterfeiting coating is DIN 55657-2016;

detecting the bonding yield: randomly extracting a batch of anti-counterfeiting labels, wherein the total number of the anti-counterfeiting labels is 1000, putting the batch of anti-counterfeiting labels into a high-low temperature damp-heat test box, performing a high-low temperature alternating test, setting the high temperature condition to be 40 ℃, setting the low temperature condition to be-10 ℃, setting the high-low temperature relative humidity to be 50%, setting the heating rate to be 1 ℃/min, keeping the temperature for 30min when the temperature is raised to a specified high temperature, changing the temperature, and after 24 hours of the test, keeping the coverage area of the anti-counterfeiting coating at the anti-counterfeiting coding position to be more than 99%, wherein the anti-counterfeiting labels are qualified products, otherwise, the anti-counterfeiting labels are unqualified;

the detection standard of the breaking elongation rate is GB/T1731-1993;

and (3) detecting the extension yield: and randomly extracting a batch of anti-counterfeit labels, wherein 1000 anti-counterfeit labels are extracted, manually folding the anti-counterfeit labels and reversely folding the anti-counterfeit labels to finish the two groups of folding operations, observing whether the crease is completely broken or not by using a 5-time magnifier after the paper is unfolded, wherein the anti-counterfeit labels which are completely broken and expose the anti-counterfeit codes are unqualified products, and the rest are qualified products.

And (3) detecting data:

TABLE 13 Performance testing of anti-counterfeiting coatings

Sample (I)	VOC content (ppm)	Sample (I)	VOC content (ppm)
				Example 1	10	Example 18	20
Example 2	10	Example 19	21
				Example 3	11	Example 20	20
Example 4	10	Example 21	20
				Example 5	12	Example 22	19
Example 6	14	Example 23	20
				Example 7	11	Example 24	21
Example 8	10	Example 25	22
				Example 9	16	Example 26	20
Example 10	19	Example 27	18
				Example 11	18	Example 28	21
Example 12	20	Example 29	26
				Example 13	19	Example 30	22
Example 14	21	Example 31	63
				Example 15	20	Comparative application example 1	17
Example 16	18	Comparative application example 2	/
				Example 17	18

TABLE 14 detection of counterfeit prevention coating performance of counterfeit prevention labels

Sample (I)	Adhesive strength (N/mm)	Whether or not to cure	Adhesion yield (%)	Elongation at Break (%)	Yield of tensile Strength (%)
						Application example 1	2.1	Curing	97.2	278	92.8
Application example 2	2.3	Curing	97.3	281	93.2
						Application example 3	2.4	Curing of	97.6	284	93.6
Application example 4	2.5	Curing of	97.6	282	93.2
						Application example 5	3.0	Curing of	97.7	293	93.5
Application example 6	3.6	Curing	98.7	324	97.4
						Application example 7	3.2	Curing	98.3	316	96.5
Application example 8	2.7	Curing	97.8	315	96.4
						Application example 9	3.6	Curing	98.7	305	95.5
Application example 10	3.8	Curing	98.9	312	96.3
						Application example 11	3.7	Curing of	98.8	314	96.4
Application example 12	3.8	Curing of	98.9	314	96.4
						Application example 13	3.8	Curing	98.9	316	97.1
Application example 14	3.9	Curing of	99.1	316	96.2
						Application example 15	3.9	Curing	99.3	317	96.7
Application example 16	3.9	Curing	99.2	315	96.4
						Application example 17	3.9	Curing	99.4	313	96.9
Application example 18	3.9	Curing	99.4	319	96.5
						Application example 19	4.0	Curing	98.9	313	96.9
Application example 20	3.9	Curing of	99.5	319	96.2
						Application example 21	4.0	Curing	99.1	316	96.4
Application example 22	4.0	Curing	95.1	312	96.5
						Application example 23	3.9	Curing of	95.2	312	96.9
Application example 24	4.0	Curing of	95.2	319	96.5
						Application example 25	3.8	Curing	98.9	320	96.6
Application example 26	3.8	Curing	98.9	317	96.2
						Application example 27	3.9	Curing	99.2	316	97.0
Application example 28	4.2	Curing	99.3	319	96.7
						Application example 29	4.0	Curing	99.1	312	96.4
Application example 30	4.0	Curing	99.1	315	96.8
						Application example 31	4.1	Curing of	99.2	313	96.5
Comparative application example 1	1.3	Not cured	95.4	255	91.3
						Comparative application example 2	1.6	Curing	96.7	207	81.3

According to the detection results of the table:

1. the anti-counterfeiting coating can be obtained by combining application examples 1-31 and VOC detection data in Table 13, and the anti-counterfeiting coating is safe and environment-friendly, and the VOC volatilization amount is far lower than 450ppm of the standard.

2. The bonding strength and the bonding yield of the anti-counterfeit label are in a direct proportion relation in combination with application examples 1-31 and table 14, the bonding strength is higher, the bonding yield is higher, the fracture elongation and the fracture yield are also in a direct proportion relation, the fracture elongation is higher, and the fracture yield is higher, so that the coating of the anti-counterfeit label prepared by the method can be firmly attached to the anti-counterfeit label and has better toughness, and the anti-counterfeit label is not easy to fall off and fracture when being impacted by external force.

3. It can be seen by combining application example 1 and comparative application example 1 and table 14 that, in comparative application example 1, the sequence of preparation steps of the modified starch prepolymer is changed, when oxidized starch and polyvinyl alcohol are crosslinked first, the bonding strength is obviously reduced, the bonding strength is reduced from 2.1N/mm to 1.3N/mm, the breaking elongation is reduced from 278% to 255%, and the anti-counterfeiting coating is not cured after being irradiated by an ultraviolet lamp with the electric power of 600W for 30 s;

the possible reasons are: the modified starch adhesive is large in viscosity due to crosslinking of the oxidized starch and the polyvinyl alcohol, the dispersion degree of the oxidized graphene is poor, the agglomerated particles are large, the bonding strength of the anti-counterfeiting coating is reduced, the toughness is reduced, meanwhile, the photo-initiation effect of the diaryl iodonium salt on the oxidized graphene is poor, and the curing time is long, so that the anti-counterfeiting coating prepared by the modified sequence of the oxidized starch, the oxidized graphene and the polyvinyl alcohol, which is recorded in the embodiment 1, is large in adhesive strength, good in toughness, short in curing time, and high in printing quality.

4. As can be seen from the combination of application example 1 and comparative application examples 1-2 and table 13, the following defects are present when no graphene oxide is doped in comparative application example 2: firstly, the bonding strength of the anti-counterfeiting coating is reduced; secondly, the graphene oxide is lacked, the tensile fracture rate of the graphene oxide is also obviously reduced, and the toughness is poor; finally, the curing mode of the anti-counterfeiting coating is changed, the curing time is obviously prolonged, and meanwhile, the main action of photoinitiation on the graphene oxide can be inferred by combining with the comparative application examples 1-2.

5. It can be seen from combination of application examples 1 to 4 and application examples 5 to 7 and combination of table 14 that the doping amount of the graphene oxide has an obvious effect on the adhesive strength and the elongation at break of the anti-counterfeiting coating, and the optimal doping amount of the graphene oxide is the doping amount of application example 6.

6. In combination with application examples 1 and 25-31 and Table 14, it can be seen that the larger the mass ratio of the modified starch prepolymer to the diaryl iodonium salt, the larger the degree of crosslinking between the modified starch prepolymer and the diaryl iodonium salt, and the optimal ratio of the modified starch prepolymer to the diaryl iodonium salt in the anti-counterfeiting coating is the ratio of application example 28.

In summary, the best preparation method of the anti-counterfeit label is the preparation method described in application example 28.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The anti-counterfeiting coating is characterized by being prepared from the following raw materials in parts by mass:

100-200 parts of modified starch prepolymer

Diaryl iodonium salt 1-2 weight portions

The modified starch prepolymer is prepared by the following steps:

s2, adding polyvinyl alcohol into distilled water, wherein the mass ratio of the polyvinyl alcohol to the oxidized starch is (0.14-0.24): 1, stirring and heating until the polyvinyl alcohol is completely dissolved to obtain a polyvinyl alcohol solution; keeping the temperature of the polyvinyl alcohol solution for 10min, and then cooling to 50-60 ℃;

s3, adding the polyvinyl alcohol solution into the modified starch milk, and uniformly stirring to obtain a modified starch prepolymer; the alcoholysis degree of the polyvinyl alcohol is 60-88%.

2. An anti-counterfeiting coating according to claim 1, wherein: the oxidized starch has a carboxyl content of 0.1 to 0.3 wt.%.

3. An anti-counterfeiting coating according to claim 2, wherein: the mass ratio of the graphene oxide to the oxidized starch is 1 (80-100).

4. An anti-counterfeiting coating according to claim 3, wherein: in the step S1, the ultrasonic frequency of the graphene oxide is 50Hz, and the ultrasonic time is 1h.

5. An anti-counterfeiting coating according to claim 4, characterized in that: the mass ratio of the polyvinyl alcohol to the oxidized starch in the step S2 is (0.18-0.20): 1.

6. An anti-counterfeiting coating according to claim 5, wherein: and S3, adding the polyvinyl alcohol solution into the modified starch milk, and stirring for 0.3-0.5h.

7. A printing process of an anti-counterfeit label is characterized by comprising the following steps: the method comprises a label pattern printing step, a laminating film printing step and an anti-counterfeiting layer printing step;

wherein, the anti-counterfeiting layer printing step is:

and (3) performing screen printing on the paper substrate treated by the laminating film printing step by using the anti-counterfeiting coating of any one of claims 1 to 6, and curing by ultraviolet lamp irradiation to obtain the anti-counterfeiting layer for covering the label pattern.

8. An anti-counterfeit label is characterized in that: the anti-counterfeiting label is prepared by the anti-counterfeiting label printing process of claim 7.