High-barrier paper-based composite material with optical anti-counterfeiting performance and preparation method of high-barrier paper-based composite material

Abstract

The invention relates to the field of new materials, in particular to a high-barrier paper-based composite material with optical anti-counterfeiting performance and a preparation method thereof.The degradable organic material is selected for pre-coating and protective coating, the barrier performance of the paper-based composite material is enhanced, the organic material is coated with an inorganic nano-material to form a compact inorganic color developing layer, and the barrier property of the paper-based composite material is improved. The barrier property is enhanced while anti-counterfeiting color development is realized, in addition, carbon black is added into the inorganic color development layer, so that the color brightness is improved, the barrier property of the material is further enhanced, and the purposes of high barrier property, color development and anti-counterfeiting of the paper-based composite material are achieved.

Description

Technical Field

[0001] The present invention relates to the field of new materials, and in particular to a high-barrier paper-based composite material with optical anti-counterfeiting performance and a preparation method thereof. Background Art

[0002] With the development of economy and the enhancement of people's environmental awareness, people have put forward higher requirements for packaging materials, especially food packaging and electronic device packaging. Petroleum-based plastics are the most common high-barrier materials in packaging applications, but most of them are non-degradable polymers. In order to reduce the use of non-degradable plastics and resource consumption and deal with environmental pollution, people have focused more on how to replace petroleum-based plastic packaging materials with greener and more environmentally friendly bio-based materials while ensuring that the products have high barrier properties.

[0003] As an environmentally friendly bio-based packaging material, paper has become a research hotspot for new packaging materials. Domestic and foreign research teams are actively studying how to effectively improve the barrier properties of paper-based materials. Multilayer coating of organic and biopolymers on paper and construction of inorganic nanomaterial gas barriers are two effective strategies to improve the oxygen and moisture barrier properties of paper or composite films. Surface sizing can be used to apply different functional layers according to actual requirements to increase the performance of composite films.

[0004] In addition, it is very important to display special colors and print specific color patterns and trademarks on paper-based packaging films, which helps to display product information and has anti-counterfeiting functions. The chemical colors of traditional pigment dyeing are produced by selective absorption of visible light, which often causes light fading with the loss of photoelectric energy and electron transfer, and the anti-counterfeiting form is single. The structural color produced by colloidal crystals is more favored by researchers. It is a color produced by the interaction of visible light and periodic structure, with high brightness, high stability, and color saturation. It has great application potential in sensing, anti-counterfeiting and other fields.

[0005] However, when the structural color of colloidal crystals is applied to paper-based packaging films, its waterproof ability is poor, the color development is unstable, and there is also the problem of unsatisfactory barrier performance. Therefore, there is an urgent need to develop paper-based composite materials with high barrier properties, anti-counterfeiting color development and waterproof properties. Summary of the invention

[0006] In order to solve the problems of unsatisfactory barrier properties, poor waterproof and oil-proof properties, and unstable traditional anti-counterfeiting color development of existing paper-based composite materials, and to broaden the application field of paper-based composite materials, the present invention provides a high-barrier paper-based composite material with optical anti-counterfeiting properties and a preparation method thereof, wherein degradable organic materials are selected for pre-coating and protective coating to enhance the barrier properties of the paper-based composite material, and inorganic nanomaterials are coated on the organic material to form a dense inorganic color development layer, which enhances the barrier properties while achieving anti-counterfeiting color development, and further adds carbon black to the inorganic color development layer to improve the brightness of the color and further enhance the barrier properties of the material, thereby achieving the purpose of high barrier properties and color development and anti-counterfeiting of the paper-based composite material.

[0007] The paper-based composite material provided by the present invention has strong barrier properties as well as waterproof, oil-proof and optical stability properties, and can replace traditional plastic packaging materials. At the same time, the paper-based composite material of the present invention also has the characteristic of color display at specific angles, which can achieve angle anti-counterfeiting and broaden the application field of the paper-based composite material.

[0008] The specific technical solutions of the present invention are as follows: A high-barrier paper-based composite material with optical anti-counterfeiting performance, whose structure can be divided into a paper base layer, a first organic barrier layer, an inorganic color development layer and a second organic barrier layer, wherein the first organic barrier layer is a degradable polymer dispersion with excellent oxygen barrier performance; the second layer is an inorganic color development layer, and the prepared inorganic nanomaterial is dispersed in a solvent to form a saturated solution, and carbon black is added to make the coated inorganic layer denser, achieving high oxygen and water vapor barrier effects while showing bright colors; the third layer of the second organic barrier layer adopts a waterproof polymer dispersion. This paper-based composite material has high barrier properties and can show color at specific angles, and different colors can be observed at different observation angles, thereby realizing angle anti-counterfeiting.

[0009] The final high-barrier paper-based composite material with optical anti-counterfeiting performance can have a Cobb value (1800 s) as low as 1.7g / m 2 , oxygen transmission rate can be as low as 0.723 cm 3 / m 2 ·d·0.1 MPa, water vapor transmission rate can be as low as 8.35 g / m 2 ·24h.

[0010] Furthermore, the coating liquid of the first organic barrier layer is a dispersion of degradable organic matter; the degradable organic matter includes but is not limited to one or more of polyvinyl alcohol, starch, polylactic acid, chitosan, and protein.

[0011] The coating liquid of the inorganic color developing layer is formed by orderly assembling inorganic nanomaterials and carbon black under heat treatment, wherein the inorganic nanomaterials include but are not limited to one or more particles or microspheres of silicon dioxide, titanium dioxide, zinc oxide, iron oxide, and copper sulfide, wherein the particle size of the inorganic nanomaterial ranges from 30 to 500 nm, and the particle size of the carbon black ranges from 30 to 40 nm.

[0012] The coating liquid of the second organic barrier layer is a dispersion of a high-strength degradable material, and the high-strength degradable material includes but is not limited to one or more of polyacrylate, water-based polyurethane, and polylactic acid.

[0013] Furthermore, the molecular weight of the degradable organic matter is 20000-500000, the dispersant of the degradable organic matter dispersion is water, the mass fraction is 5-15wt%, and the viscosity is 1500 Pa·s - 4500 Pa·s; preferably, the coating amount of the degradable organic matter after drying is controlled to be 2 g / m 2 - 10 g / m 2 .

[0014] Preferably, the molecular weight of the high-strength degradable material is 1000-200000, the dispersant is water, the mass fraction is 10-20wt%, the viscosity is 3000-6000 Pa·s, and the coating amount of the high-strength degradable material after drying is 6-15g / m 2 .

[0015] Preferably, the coating liquid of the inorganic color developing layer is coated on the first organic barrier layer to form a thin, continuous and smooth wet film, and the total coating amount after drying is 2-5 g / m 2 The preparation method of the coating liquid of the inorganic color development layer is as follows: a certain mass of inorganic nanomaterial is dispersed in a dispersant to obtain a dispersion of the inorganic nanomaterial, and then carbon black is added in an amount of 0.1-0.2wt% of the mass of the inorganic nanomaterial, and the inorganic color development layer coating liquid is obtained by sufficiently ultrasonicating for 30-60 minutes to make it dispersed evenly.

[0016] Preferably, the dispersant is ethanol, water or ethylene glycol, and the mass fraction of the inorganic nanomaterial in the inorganic nanomaterial coating solution is 20-30wt%.

[0017] Preferably, the dispersant is ethylene glycol, and most preferably a combination of ethylene glycol and ethanol. In this case, the method for preparing the coating liquid of the inorganic color developing layer is as follows: firstly dispersing the inorganic nanomaterial in ethanol to obtain an ethanol dispersion with a mass fraction of 7.75wt%, and then adding a certain amount of ethylene glycol to the ethanol dispersion, wherein the ratio of the inorganic nanomaterial to the ethylene glycol in the dispersion is 0.038 cm 3: 62 μL; after sufficient ultrasonic dispersion, drying was carried out at 70°C for 2 h to dry the ethanol, thereby obtaining a coating solution for the inorganic color developing layer.

[0018] The good dispersibility of carbon black can reduce the agglomeration of inorganic nanomaterials. Its structural characteristics can improve the scattering and absorption capacity of inorganic nanomaterials to light, enhance the brightness of the color, and at the same time improve the barrier properties of the inorganic color development layer. When ethylene glycol is used as a dispersant, ethanol is first used to make an ethanol dispersion, which mainly plays the role of well dispersing inorganic nanomaterials.

[0019] In the inorganic color-developing layer formed by the inorganic nanoparticles, the orderly arrangement of the inorganic nanoparticles can form a tortuous path that is more difficult for gas molecules to pass through, and has a synergistic effect with the first organic barrier layer and the second organic barrier layer, further enhancing the barrier properties of the material; carbon black is added to the inorganic coating liquid, which can not only reduce the agglomeration of the inorganic nanomaterials, but also enhance the brightness and saturation of the color, and at the same time synergize with the inorganic nanomaterials to improve the barrier properties of the inorganic materials.

[0020] The inorganic nanomaterial is assembled on the first organic barrier layer, and the total thickness of the inorganic color development layer is 2-10 nm.

[0021] After the inorganic nanomaterials are assembled on the first organic barrier layer, they can show specific, bright colors in the presence of light and at a certain observation angle. The color can be changed by adjusting the particle size of the inorganic nanomaterials. In addition, different colors can be observed when observing the same inorganic color-developing layer at different observation angles.

[0022] The present invention further provides a method for preparing the high-barrier paper-based composite material with optical anti-counterfeiting performance, comprising the following steps: 1) taking a degradable organic matter dispersion as a coating liquid for a first organic barrier layer, coating it on a paper base layer, and drying the water layer to obtain the first organic barrier layer; 2) coating the coating liquid of the inorganic color developing layer on the first organic barrier layer to form a thin, continuous and smooth wet film, and performing heat treatment. The inorganic nanomaterials are orderly assembled during the heat treatment to form a bright and dense inorganic color developing layer; 3) The high-strength biodegradable material dispersion is coated on the inorganic color development layer and then dried to obtain the product.

[0023] Preferably, in step 1), step 2) and step 3), the coating is continuous coating, and the coating method includes but is not limited to wire rod coating, blade coating, spray coating and spin coating, and can be carried out using a conventional coating machine.

[0024] Preferably, the heat treatment in step 2) is drying, the drying temperature in step 1), step 2) and step 3) is 60-100° C., and the drying methods include but are not limited to infrared drying, hot air drying and steam drying.

[0025] The high-barrier paper-based composite material with optical anti-counterfeiting performance and the preparation method thereof proposed in the present invention have achieved the following beneficial effects: (1) The present invention is based on organic-inorganic composite technology. Inorganic nanomaterials are coated on the organic layer. The inorganic nanomaterials are orderly assembled and arranged to form a thin and continuous inorganic color development layer. Under the joint action of organic degradable materials, the barrier properties of paper-based composite materials are effectively improved. The Cobb value (1800 s) is as low as 1.7 g / m 2 , oxygen transmission rate can be reduced to 0.723cm 3 / m 2 ·d·0.1 MPa, water vapor transmission rate can be reduced to 8.35 g / m 2 •24h; (2) Inorganic nanomaterials selectively reflect light and can show red, yellow, green and blue colors at specific angles, making the paper-based composite material have angular anti-counterfeiting properties. Carbon black enhances the color saturation and brightness, improving the barrier properties of the material. (3) This technology uses inorganic materials and degradable organic matter, which is green and environmentally friendly with a high degradation rate; (4) The present invention adopts a continuous coating process, can be prepared in large quantities, is suitable for in-line operation, has high efficiency and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a high-barrier paper-based composite material with optical anti-counterfeiting properties of the present invention, wherein the main body is divided into four layers: a paper base layer 1, a first organic barrier layer 2, an inorganic color development layer 3, and a second organic barrier layer 4; Figure 2 The paper-based composite material prepared with silica microspheres as the inorganic color development unit in Example 1, (a) is the color of the paper-based composite material observed at 10°, and (b) is the color of the paper-based composite material observed at 50°; Figure 3 The paper-based composite material prepared with silica microspheres as the inorganic color development unit in Example 2, (a) is the color of the paper-based composite material observed at 10°, and (b) is the color of the paper-based composite material observed at 50°; Figure 4 This is a scanning electron microscope image of the cross section of the sample in Example 2 and the structure of each layer therein. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below in conjunction with specific embodiments. These embodiments are only used to illustrate the technical solution of the present invention in more detail and should not be construed as limiting the protection scope of the present invention.

[0028] See also Figure 1 The present invention provides a high-barrier paper-based composite material with optical anti-counterfeiting performance, and its structure can be divided into a paper base layer, a first organic barrier layer, an inorganic color development layer and a second organic barrier layer. The first organic barrier layer is a degradable organic dispersion that blocks oxygen, and the third layer is the second organic barrier layer, which is a waterproof high-strength degradable material dispersion. The key second layer is an inorganic color development layer, which is made by dispersing a certain mass of inorganic nanomaterials into ethanol, ethylene glycol or water, adding a certain mass of carbon black to form an inorganic nanomaterial dispersion, and forming a dense barrier layer after coating, forming a tortuous path, and synergizing with the organic layer to achieve high oxygen and water vapor barrier effects. At the same time, the inorganic nanomaterials are assembled in an orderly manner to form structural colors, showing different colors at specific angles, and realizing angle anti-counterfeiting.

[0029] Example 1 A method for preparing a high-barrier paper-based composite material with optical anti-counterfeiting performance comprises the following steps: (1) The paper base material is 60 g / m 2 Printing paper; 1799 type polyvinyl alcohol with an average molecular weight of 83300 was selected as the coating liquid for preparing the first organic barrier layer of the degradable organic matter, and a polyvinyl alcohol aqueous solution with a mass fraction of 10 wt% and a viscosity of 2500 Pa·s was prepared. A 50 μm wire rod was used for single-sided coating on the paper base layer. The coating speed was 10 mm / s. After coating, hot air drying was performed for 10 min at a temperature of 70°C. The coating amount of 1799 type polyvinyl alcohol after drying was controlled to be 5 g / m 2 , forming a first organic barrier layer.

[0030] (2) Silica microspheres with a particle size of 330 nm were selected as inorganic nanomaterials. A certain amount of silica microspheres was dispersed in ethanol to prepare a silica ethanol dispersion with a mass fraction of 7.75 wt%. The dispersion was fully ultrasonically dispersed and then the ratio of inorganic nanomaterial to ethylene glycol was 0.038 cm 3:62 μL of silica ethanol dispersion and ethylene glycol were mixed, 0.1 wt% of carbon black based on the mass of silica microspheres was added, and then the mixture was fully ultrasonicated for 30 min to disperse it evenly, so that the silica microspheres were evenly dispersed in the mixture, and the ethanol in the mixture was dried with hot air at a temperature of 70°C for 2 h to obtain a dispersion of an inorganic color development layer; a 20 μm wire rod was used for single-sided coating to coat the dispersion of the inorganic color development layer on the first organic barrier layer at a coating speed of 5 mm / s, and after coating, hot air drying was performed for 10 min at a drying temperature of 70°C to form an inorganic color development layer, and the total coating amount of the inorganic layer after drying was controlled to be 3 g / m 2 .

[0031] (3) The coating liquid of the second organic barrier layer is a polyacrylate emulsion, which is a 15 wt% aqueous emulsion with a viscosity of 4000 Pa·s. A 50 μm wire rod is used for coating at a coating speed of 10 mm / s. After coating, hot air drying is performed for 10 min at a drying temperature of 80°C. The polyacrylate content in the composite material after drying is controlled to be 8 g / m 2 , forming a second organic barrier layer.

[0032] Finally, a high-barrier paper-based composite material with optical anti-counterfeiting performance based on silica microspheres was obtained, and its color and anti-counterfeiting properties were as follows: Figure 2 a, at an observation angle of 10°, the color of the paper-based composite material is red. Figure 2 b, At an observation angle of 50°, the color of the paper-based composite material is yellow.

[0033] After testing (oxygen permeability is tested according to national standard GB1038-2000, water vapor permeability is tested according to national standard GB / T1037-2021, Cobb (1800s) is tested according to national standard GB / T1540-2002), its basic performance is: oxygen permeability can be reduced to 0.723 cm 3 / m 2 24h 0.1MPa, water vapor transmission rate can be reduced to 8.35 g / m 2 24h, Cobb value (1800s) can be as low as 1.7 g / m 2 .

[0034] According to the above coating conditions, only the first organic barrier layer and the inorganic color development layer are coated on the paper sample to obtain paper sample X. The basic properties of paper sample X are: the oxygen permeability can be reduced to 1.579 cm 3 / m 2 ·24h·0.1MPa, water vapor transmission rate is 569.54 g / m 224h, Cobb value (1800s) is 7.6 g / m 2 .

[0035] After testing, the water vapor transmission rate of paper sample X without polyacrylate coating (569.54 g / m 2 ·24h) and Cobb value (7.6 g / m 2 ) are much higher than the above-mentioned paper sample coated with polyacrylate (water vapor transmission rate: 8.35 g / m 2 24h, Cobb value (1800s): 1.7 g / m 2 ), showing poor water resistance, indicating that the coating of the second organic layer significantly increases the water resistance of the material. In addition, the oxygen permeability of paper sample X (1.579 cm 3 / m 2 ·24h·0.1MPa) is also higher than the paper sample coated with polyacrylate (0.723 cm 3 / m 2 ·24h·0.1MPa), indicating that the coating of the second organic layer improves the material's ability to block oxygen and protects the inorganic color-developing layer.

[0036] Example 2 A method for preparing a high-barrier paper-based composite material with optical anti-counterfeiting performance comprises the following steps: (1) The paper base material is 28 g / m 2 The first organic barrier layer of the thin paper is prepared by using polyvinyl alcohol and potato starch as solvents, the mass ratio of polyvinyl alcohol to potato starch is 1:1, the polyvinyl alcohol is 1799 type, the average molecular weight is 83300, the molecular weight of potato starch is 50000, the total mass fraction of starch / polyvinyl alcohol aqueous solution is 10 wt% (i.e., the mass fraction of potato starch is 5 wt%, the mass fraction of polyvinyl alcohol is 5 wt%), the viscosity is 3500 Pa·s, and the single-sided coating is performed on the paper base layer by using a 50 μm wire rod, the coating speed is 10 mm / s, and the hot air drying is performed for 10 min after coating at a temperature of 70°C, and the coating amount of the degradable organic matter after drying (i.e., the total coating amount of potato starch and polyvinyl alcohol) is controlled to be 5 g / m 2 , forming a first organic barrier layer.

[0037] (2) Silica microspheres with a particle size of 250 nm were selected as inorganic nanomaterials. A certain mass of silica microspheres was dispersed in ethanol to prepare a silica microsphere ethanol dispersion with a mass fraction of 25 wt%, and the mixture was fully and evenly dispersed by ultrasonication. After adding carbon black with a mass fraction of 0.1 wt% of the silica microspheres, the mixture was ultrasonicated for 30 min to evenly disperse the silica microspheres in the mixture to obtain a dispersion of an inorganic color development layer. A 30 μm wire rod was used for single-sided coating to coat the dispersion of the inorganic color development layer on the first organic barrier layer at a coating speed of 5 mm / s. After coating, the dispersion was dried with hot air for 10 min at a drying temperature of 70°C to form an inorganic color development layer. The coating amount of the inorganic layer after drying was controlled to be 3 g / m 2 .

[0038] (3) The coating liquid of the second organic barrier layer is a polylactic acid emulsion, which is a 10 wt% aqueous emulsion with a viscosity of 3500 Pa·s. It is coated with a 50 μm wire rod at a coating speed of 10 mm / s. After coating, it is dried with hot air at a temperature of 80°C. The amount of polylactic acid coated in the composite material after drying is controlled to be 6 g / m 2 , forming a second organic barrier layer.

[0039] Finally, a high-barrier paper-based composite material with optical anti-counterfeiting performance based on silica microspheres was obtained, and its color and anti-counterfeiting properties were as follows: Figure 3 a, At an observation angle of 10°, the color of the paper-based composite material is green. Figure 3 b, At an observation angle of 50°, the color of the paper-based composite material is blue.

[0040] Figure 4 The figure is a scanning electron microscope image of the cross section of the sample and the structure of each layer therein, wherein the layers from bottom to top are the paper base layer, the first organic barrier layer, the inorganic color development layer and the second organic barrier layer.

[0041] After testing, its basic performance is: oxygen transmission rate can be reduced to 0.73 cm 3 / m 2 24h 0.1MPa, water vapor transmission rate can be reduced to 8.5 g / m 2 · Cobb value (1800s) can be as low as 2 g / m2 within 24 hours 2 .

[0042] Example 3 A method for preparing a high-barrier paper-based composite material with optical anti-counterfeiting performance comprises the following steps: (1) The paper base material is 40 g / m 2For paper, chitosan with a relative molecular weight of 50000-60000 was selected, and 1 wt% acetic acid solution was used as the solvent to prepare a chitosan solution with a mass fraction of 3 wt% as the coating liquid of the first organic barrier layer, with a viscosity of 1000 mPa·s. A 50 μm wire rod was used to coat the paper base on one side at a coating speed of 10 mm / s. After coating, hot air drying was performed for 10 min at a temperature of 70°C. The coating amount of the degradable organic matter after drying was controlled to be 6 g / m2 to form the first organic barrier layer.

[0043] (2) Silica microspheres with a particle size of 200 nm were selected as inorganic nanomaterials, a certain mass of silica microspheres was dispersed in water to prepare a silica microsphere aqueous dispersion with a mass fraction of 30 wt%, and the silica microspheres were fully and uniformly dispersed by ultrasonication to obtain an inorganic color development layer dispersion A; Inorganic color development layer dispersion A was prepared in the same steps, and carbon black with a mass percentage of 0.1 wt% of silica microspheres was added thereto, and then ultrasonicated for 30 min to uniformly disperse the silica microspheres in the mixed solution, thereby obtaining inorganic color development layer dispersion B; A 30 μm wire rod was used for single-sided coating. The dispersions A and B of the inorganic color developing layer were coated on the first organic barrier layer of different paper samples respectively. The coating speed was 5 mm / s. After coating, hot air drying was performed for 10 min at a drying temperature of 70°C to form an inorganic color developing layer. The coating amount of the inorganic layer after drying was controlled to be 4 g / m 2 .

[0044] (3) The coating liquid of the second organic barrier layer is an aqueous polyurethane dispersion, with a mass fraction of preferably 10 wt% and a viscosity of 3500 Pa·s. A 50 μm wire rod is used for coating at a coating speed of 10 mm / s. After coating, hot air drying is performed at a drying temperature of 80°C. The polyurethane coating amount in the composite material after drying is controlled to be 6 g / m 2 , forming a second organic barrier layer.

[0045] Finally, a high-barrier paper-based composite material with optical anti-counterfeiting performance based on silica microspheres was obtained. After testing, the basic properties of the paper samples coated with inorganic color developing layer dispersions A and B were: A: Oxygen transmission rate can be reduced to 0.85 cm 3 / m 2 24h 0.1MPa, water vapor transmission rate can be reduced to 8.76 g / m 2 24h, Cobb value (1800s) can be as low as 1.9 g / m 2 ; B: Oxygen transmission rate can be reduced to 0.79 cm 3 / m 224h 0.1MPa, water vapor transmission rate can be reduced to 8.75 g / m 2 24h, Cobb value (1800s) can be as low as 1.9 g / m 2 .

[0046] Of the two different paper samples prepared above, the paper sample coated with inorganic color developing layer dispersion B (carbon black with 0.1 wt% silica microspheres added) has a water vapor transmission rate (8.75 g / m 2 ·24h) and Cobb value ((1800s) is 1.9 g / m 2 ) and the paper sample coated with the inorganic color developing layer dispersion A (without adding carbon black) (water vapor transmission rate is not 8.76 g / m 2 24h, Cobb value is 1.9 g / m 2 ), the water vapor permeability and Cobb value are almost the same, while the paper sample coated with inorganic color layer dispersion liquid B (oxygen permeability is 0.79 cm 3 / m 2 ·24h·0.1MPa) has a lower oxygen permeability than the paper sample coated with inorganic color developing layer dispersion A (oxygen permeability is 0.85 cm 3 / m 2 ·24h·0.1MPa), indicating that the addition of carbon black improves the oxygen barrier properties of the paper sample.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any equivalent substitutions, modifications, etc. made by technicians in this field without any creative work within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-barrier paper-based composite material with optical anti-counterfeiting performance, comprising a paper base layer, characterized in that: A first organic barrier layer, an inorganic color development layer and a second organic barrier layer are sequentially coated on a paper base layer, wherein the coating liquid of the first organic barrier layer is a degradable organic dispersion liquid; the coating liquid of the inorganic color development layer is formed by orderly assembling inorganic nanomaterials and carbon black under heat treatment; and the coating liquid of the second organic barrier layer is a high-strength degradable material dispersion liquid; The degradable organic matter is selected from one or more of polyvinyl alcohol, starch, polylactic acid, chitosan, and protein; The inorganic nanomaterial is selected from one or more of particles or microspheres of silicon dioxide, titanium dioxide, zinc oxide, iron oxide, and copper sulfide; The high-strength degradable material is selected from one or more of polyacrylate, waterborne polyurethane, and polylactic acid.

2. The high-barrier paper-based composite material with optical anti-counterfeiting performance according to claim 1, characterized in that: The high-barrier paper-based composite material with optical anti-counterfeiting performance has a Cobb value as low as 1.7 g / m 2 , oxygen transmission rate as low as 0.723 cm 3 / m 2 ·d·0.1 MPa, water vapor transmission rate as low as 8.35 g / m 2 ·24h.

3. The high-barrier paper-based composite material with optical anti-counterfeiting performance according to claim 1, characterized in that: The molecular weight of the degradable organic matter is 20000-500000, the dispersant of the degradable organic matter dispersion is water, the mass fraction is 5-15wt%, the viscosity is 1500 Pa·s-4500 Pa·s, and the coating amount of the degradable organic matter after drying is 2 g / m 2 - 10g / m 2 .

4. The high-barrier paper-based composite material with optical anti-counterfeiting performance according to claim 1, characterized in that: The molecular weight of the high-strength degradable material dispersion is 1000-200000, the dispersant is water, the mass fraction is 10-20wt%, the viscosity is 3000-6000 Pa·s, and the coating amount of the high-strength degradable material after drying is 6-15g / m 2 .

5. The high-barrier paper-based composite material with optical anti-counterfeiting performance according to claim 1, characterized in that: The coating liquid of the inorganic color developing layer is coated on the first organic barrier layer to form a thin, continuous and smooth wet film. After drying, the total coating amount is 2-5 g / m 2 The inorganic nanomaterial is assembled on the first organic barrier layer, and its thickness is 2-10nm; the preparation method of the coating liquid of the inorganic color developing layer is: dispersing a certain mass of inorganic nanomaterial into a dispersant to obtain a dispersion of the inorganic nanomaterial, adding carbon black, the amount of carbon black added is 0.1-0.2wt% of the mass of the inorganic nanomaterial, and fully ultrasonicating it to make it evenly dispersed to obtain the coating liquid of the inorganic color developing layer.

6. The high-barrier paper-based composite material with optical anti-counterfeiting performance according to claim 5, characterized in that: The particle size of inorganic nanomaterials ranges from 30 to 500 nm, and the particle size of carbon black is 30-40 nm.

7. The high-barrier paper-based composite material with optical anti-counterfeiting performance according to claim 5, characterized in that: The dispersant is ethanol, water or ethylene glycol, and the mass fraction of the inorganic nanomaterial in the inorganic nanomaterial coating solution is 20-30wt%.

8. The method for preparing the high-barrier paper-based composite material with optical anti-counterfeiting performance according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) taking a degradable organic matter dispersion as a coating liquid for a first organic barrier layer, coating it on a paper base layer, and drying the water layer to obtain the first organic barrier layer; 2) coating the coating liquid of the inorganic color developing layer on the first organic barrier layer to form a thin, continuous and smooth wet film, and performing heat treatment. The inorganic nanomaterials are orderly assembled during the heat treatment to form a bright and dense inorganic color developing layer; 3) The high-strength biodegradable material dispersion is coated on the inorganic color development layer and then dried.

9. The preparation method according to claim 8, characterized in that: The coating in step 1), step 2) and step 3) is continuous coating, and the coating method is selected from wire rod coating, doctor blade coating, spray coating or spin coating.

10. The preparation method according to claim 8, characterized in that: The heat treatment in step 2) is drying, the drying temperature in step 1), step 2) and step 3) is 60-100°C, and the drying method is selected from infrared drying, hot air drying or steam drying.

Images