阅读说明：本技术 激光加密防伪转移纸及其制备方法 (Laser encrypted anti-counterfeiting transfer paper and preparation method thereof ) 是由 张凤凤 巩运军 姜丽明 赵振虎 王艳玲 于 2020-06-12 设计创作，主要内容包括：本发明属于防伪技术产品领域,具体涉及一种激光加密防伪转移纸及其制备方法。所述的防伪转移纸包括从上到下依次设置的表涂层、转移涂层、激光加密信息层、铝层、转移胶层、白卡纸层和背涂层,所述的激光加密信息层包含隐藏信息,隐藏信息在点光源下显现。本发明所述的激光加密防伪转移纸,设有激光加密信息层,激光加密信息层内隐藏数字编码信息光栅结构,自然光下,加密信息隐藏,使用手持式点光源设备照射转移纸,呈现隐藏信息,消费者通过鉴别隐藏信息,判断产品真伪,便于消费者查询真伪；通过数学算法进行加密,防伪力度高,不易被破解伪造,增加仿制难度；本发明的制备方法,科学合理、简单易行。(The invention belongs to the field of anti-counterfeiting technical products, and particularly relates to laser encryption anti-counterfeiting transfer paper and a preparation method thereof. The anti-counterfeiting transfer paper comprises a surface coating, a transfer coating, a laser encryption information layer, an aluminum layer, a transfer adhesive layer, a white cardboard paper layer and a back coating which are sequentially arranged from top to bottom, wherein the laser encryption information layer contains hidden information, and the hidden information is displayed under a point light source. The laser encryption anti-counterfeiting transfer paper is provided with a laser encryption information layer, a digital coding information grating structure is hidden in the laser encryption information layer, encryption information is hidden under natural light, the transfer paper is irradiated by using handheld point light source equipment, hidden information is presented, a consumer judges the authenticity of a product by identifying the hidden information, and the consumer can conveniently inquire the authenticity; the encryption is carried out through a mathematical algorithm, so that the anti-counterfeiting strength is high, the anti-counterfeiting effect is not easy to crack and forge, and the imitation difficulty is increased; the preparation method is scientific, reasonable, simple and feasible.)

1. The laser encrypted anti-counterfeiting transfer paper is characterized in that: the laser card paper comprises a surface coating, a transfer coating, a laser encryption information layer, an aluminum layer, a transfer adhesive layer, a white card paper layer and a back coating which are sequentially arranged from top to bottom, wherein the laser encryption information layer contains hidden information, and the hidden information appears under a point light source.

2. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the surface coating is a modified acrylic emulsion with the dry coating weight of 0.5-1g/m²。

3. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the transfer coating is a transferable thermoplastic acrylic resin layer, and the dry coating weight is 0.8-1.6g/m²。

4. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the laser encrypted information layer is internally hidden with digital coding information.

5. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the hidden information of the laser encryption information layer is composed of a plurality of square grating lattice arrays, the processing mode is laser etching, and grating lattices contain two parameters of grating space frequency and grating angle.

6. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the hidden information of the laser encryption information layer comprises characters, letters, numbers, symbols or figures.

7. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the thickness of the aluminum layer is

8. The laser encryption anti-counterfeiting transfer paper as set forth in claim 1, wherein: the transfer glue layer is glue of a carboxylic styrene-butadiene system or glue of a modified acrylic acid system, and the coating dry weight is 1-2g/m²(ii) a The back coating is water-based polyvinyl alcohol emulsion with the coating dry weight of 0.5-1g/m²。

9. A method for preparing laser encryption anti-counterfeiting transfer paper as claimed in any one of claims 1 to 8, which is characterized in that: the method comprises the following steps:

(1) selecting a PET base film with a corona on one side, and coating a transfer coating on the corona surface;

(2) manufacturing a laser encrypted information layer mould pressing plate:

firstly, manufacturing a hidden pattern, placing the hidden pattern in a polar coordinate system, randomly extracting N (N is N x N) pixel points according to a system sampling method, wherein N is more than or equal to 4, respectively calculating the distance rho between each pixel point and the zero point of the coordinate system and the included angle theta, obtaining an N x N matrix according to the distance between each pixel point and the zero point of the coordinate system, and finally obtaining an empty-frequency gray-scale map matrix G; obtaining an n x n matrix according to an included angle between each pixel point and a zero point of a coordinate system, finally obtaining an angle gray-scale map matrix H, and completing plate making work of a laser encryption information layer mould pressing layer in a photoetching machine according to a space frequency gray-scale map matrix G and the angle gray-scale map matrix H to obtain a laser encryption information layer mould pressing plate;

(3) copying the laser encryption information onto the transfer coating by using a molding press to form a laser encryption information layer;

(4) vacuum evaporating an aluminum layer on the laser encrypted information layer;

(5) selecting a white cardboard, and coating back coating emulsion on the back of the paper;

(6) coating transfer glue on the aluminum surface of the transfer film encrypted by laser, and compounding the transfer glue and the front surface of the white cardboard;

(7) peeling off the PET base film, and transferring all the other layer structures to the surface of the ivory board;

(8) coating a varnish layer suitable for printing on the surface of the transfer coating to form a surface coating;

(9) and cutting and transversely cutting to form a single piece of laser encrypted anti-counterfeiting transfer paper.

10. The method for preparing laser encryption anti-counterfeiting transfer paper according to claim 9, characterized by comprising the following steps: the manufacturing method of the laser encryption information layer mould pressing plate comprises the following steps:

(1) according to the design file, making a hidden pattern, establishing a polar coordinate system, and placing the pattern at a zero point in the polar coordinate system;

(2) the resolution of the pattern is a x b, and a x b pixel point groups are shared in the patternAccording to the system sampling method, N (N ═ N × N) pixel points are randomly extracted, wherein N is more than or equal to 4, and the coordinate value (x) of each pixel point is calculated by using a computer₁，y₁)、(x₂，y₂)、(x₃，y₃)、……(x_N，y_N) And the distance (p) of each pixel point from the zero point₁、ρ₂、ρ₃、……ρ_N)；

(3) Calculating the included angle (theta) between each pixel point and the zero point according to the polar coordinate system formula x ═ rho cos theta and y ═ rho cos theta₁、θ₁、θ₁、……θ_N)；

(4) L is an observation distance and is a fixed parameter, β is a grating angle, d is a grating pitch, λ is a laser wavelength, β can be obtained according to tan β ═ ρ/L, and a grating pitch d can be obtained according to a grating equation sin β ═ λ/d, at which time a two-dimensional parameter (d) for each grating lattice can be established (d is a fixed parameter)₁，θ₁)、(d₂，θ₂)、(d₃，θ₃)……(d_N，θ_N)；

(5) From the grating pitch d of the N grating lattices, a matrix can be obtained as follows:

d₁，d₂，……………………d_n

d_n+1，d_n+2，………………d_2*n

………………………………

d_n*(n-1)+1，d_n*(n-1)+2，……d_n*n

calculating to obtain the maximum value d of d_maxAnd a minimum value d_minThe minimum value corresponds to a gray value of 0 and the maximum value corresponds to a gray value of 255, and according to the corresponding relationship, the values of N d can be mapped to another matrix G composed of gray values, and the matrix G constitutes a gray map as follows:

G₁，G₂，……………………G_n

G_n+1，G_n+2，………………G_2*n

………………………………

G_n*(n-1)+1，G_n*(n-1)+2，……G_n*n；

(6) from the angles θ of the N grating lattices, a matrix can be obtained as follows:

θ₁，θ₂，……………………θ_n

θ_n+1，θ_n+2，………………θ_2*n

………………………………

θ_n*(n-1)+1，θ_n*(n-1)+2，……θ_n*n

calculating to obtain the maximum value theta of theta_maxAnd minimum value theta_minThe minimum value corresponds to a gray value of 0 and the maximum value corresponds to a gray value of 255, and according to the corresponding relationship, the values of N θ can be mapped to another matrix H composed of gray values, and the matrix constitutes a gray map as follows:

H₁，H₂，……………………H_n

H_n+1，H_n+2，………………H_2*n

………………………………

H_n*(n-1)+1，H_n*(n-1)+2，……H_n*n；

(7) manufacturing an exposure unit according to the photoetching space frequency gray matrix G and the grating angle gray matrix H, wherein the size of the exposure unit is a square with the side length of n/R mm, R is the resolution of a photoetching image, and R is more than 10dpi and less than 50800 dpi;

(8) and (4) forming the exposure unit array in the step (7) into a designed size, manufacturing the exposure unit array on a photoetching offset plate through a photoetching process, and developing and electroplating to obtain the laser encryption information layer mould pressing plate.

Technical Field

The invention belongs to the field of anti-counterfeiting technical products, and particularly relates to laser encryption anti-counterfeiting transfer paper and a preparation method thereof.

Background

The laser holographic transfer paper can be used for packaging commodities such as cigarette packets, wine packets, cosmetics, medicines, high-grade gifts and the like due to the excellent performance of the laser holographic transfer paper. As this technology matures, many counterfeit and shoddy products appear in the market, and the consumer has poor ability to distinguish between true and false in this respect, so that the consumer's interest is damaged and the manufacturer is also subjected to credit loss to various degrees.

The introduction of laser die stamping holographic anti-counterfeiting technology into China is that hundreds of production lines are introduced all over the country in the late 80 s and early 90 s, especially in the period from 1990 to 1994, and account for more than half of the world manufacturers at that time. In the early stage of introduction, the anti-counterfeiting technology indeed plays a certain anti-counterfeiting role, but as time goes on, the laser holographic image making technology is rapidly diffused, so that counterfeiters have broken through from various aspects nowadays, the anti-counterfeiting capability is almost completely lost, and people have to seek to improve the prior art. Therefore, optical image coding encryption technologies such as laser reading, optical micro-lithography, low-frequency lithography, random interference fringes and moire fringes are adopted, all the technologies need professional detection equipment to identify the authenticity, so that many consumers cannot use the anti-counterfeiting characteristics to identify the authenticity, and the market popularization is not facilitated.

Chinese patent CN110453534A discloses a method for producing local laser holographic transfer paper, comprising the following steps: (1) coating: manufacturing a special coating anilox roller according to the layout design requirement of the local transfer paper, and locally coating a transfer coating on the PET base film; (2) die pressing: molding the laser holographic anti-counterfeiting information on a molding press, wherein the holographic information can be molded in an area coated with the transfer coating, and the holographic information can not be molded in an area not coated with the transfer coating; (3) aluminum plating: aluminizing according to a normal laser holographic aluminizing process, wherein an area coated with a transfer coating is coated with an aluminum layer, an area not coated with the transfer coating is coated with the aluminum layer, and the aluminum layer is attached to the PET base film; (4) composite stripping: and (3) coating a transfer adhesive on a full plate on a compound machine to compound the aluminum layer surface of the laser holographic local transfer film with paper, and then timely peeling off the PET base film to obtain the local transfer paper. But the adopted holographic anti-counterfeiting label is common holographic anti-counterfeiting and is easy to forge.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide laser encryption anti-counterfeiting transfer paper which comprises a laser encryption information layer, wherein encryption information is hidden under natural light, and hidden information is presented under the irradiation of point light source equipment, so that a consumer can conveniently inquire authenticity, and the anti-counterfeiting transfer paper is high in anti-counterfeiting strength and not easy to crack and forge; the invention also provides a preparation method of the composition, which is scientific, reasonable, simple and feasible.

The invention is realized by the following technical scheme:

the laser encryption anti-counterfeiting transfer paper comprises a surface coating, a transfer coating, a laser encryption information layer, an aluminum layer, a transfer adhesive layer, a white cardboard paper layer and a back coating which are sequentially arranged from top to bottom, wherein the laser encryption information layer contains hidden information, and the hidden information is displayed under a point light source.

The surface coating is a modified acrylic emulsion with the dry coating weight of 0.5-1g/m²。

The transfer coating is a transferable thermoplastic acrylic resin layer, and the dry coating weight is 0.8-1.6g/m²。

The laser encrypted information layer is internally hidden with digital coding information.

The hidden information of the laser encryption information layer is composed of a plurality of square grating lattice arrays, the processing mode is laser etching, and grating lattices contain two parameters of grating space frequency and grating angle.

The hidden information of the laser encryption information layer comprises one or more of characters, letters, numbers, symbols or figures.

The laser encrypted information layer is attached to the transfer coating and can be directly detected by using a handheld point light source.

The thickness of the aluminum layer is

The transfer glue layer is glue of a carboxylic styrene-butadiene system or glue of a modified acrylic acid system, and the coating dry weight is 1-2g/m²。

The back coating is water-based polyvinyl alcohol emulsion with the coating dry weight of 0.5-1g/m²。

The preparation method of the laser encryption anti-counterfeiting transfer paper comprises the following steps:

(1) selecting a single-sided corona PET base film with the thickness of 12-28 mu m, and coating a transfer coating on the corona surface;

(2) manufacturing a laser encrypted information layer mould pressing plate:

firstly, manufacturing a hidden pattern, placing the hidden pattern in a polar coordinate system, randomly extracting N (N is N x N) pixel points according to a system sampling method, wherein N is more than or equal to 4, respectively calculating the distance rho between each pixel point and the zero point of the coordinate system and the included angle theta, obtaining an N x N matrix according to the distance between each pixel point and the zero point of the coordinate system, and finally obtaining an empty-frequency gray-scale map matrix G; obtaining an n x n matrix according to an included angle between each pixel point and a zero point of a coordinate system, finally obtaining an angle gray-scale map matrix H, and completing plate making work of a laser encryption information layer mould pressing layer in a photoetching machine according to a space frequency gray-scale map matrix G and the angle gray-scale map matrix H to obtain a laser encryption information layer mould pressing plate;

(3) copying the laser encryption information onto the transfer coating by using a molding press to form a laser encryption information layer;

(4) vacuum evaporating an aluminum layer on the laser encrypted information layer;

(5) the gram weight is selected to be 150-300g/m²The white cardboard of (2) is coated with back coating emulsion on the back surface of the paper;

(6) coating transfer glue on the aluminum surface of the transfer film encrypted by laser, and compounding the transfer glue and the front surface of the white cardboard;

(7) peeling off the PET base film, and transferring all the other layer structures to the surface of the ivory board;

(8) coating a varnish layer suitable for printing on the surface of the transfer coating to form a surface coating;

(9) and cutting and transversely cutting to form a single piece of laser encrypted anti-counterfeiting transfer paper.

Preferably, the manufacture of the laser-encrypted information layer embossing plate comprises the following steps:

(1) according to the design file, making a hidden pattern, establishing a polar coordinate system, and placing the pattern at a zero point in the polar coordinate system;

(2) the resolution of the pattern is a b, the pattern is composed of a b pixel points, N (N is N) pixel points are randomly extracted according to a system sampling method, wherein N is more than or equal to 4, and a computer is used for calculating the coordinate value (x) of each pixel point₁，y₁)、(x₂，y₂)、(x₃，y₃)、……(x_N，y_N) And the distance (p) of each pixel point from the zero point₁、ρ₂、ρ₃、……ρ_N)；

(3) Calculating the included angle (theta) between each pixel point and the zero point according to the polar coordinate system formula x ═ rho cos theta and y ═ rho cos theta₁、θ₁、θ₁、……θ_N)；

(4) L is an observation distance and is a fixed parameter, β is a grating angle, d is a grating pitch, λ is a laser wavelength, β can be obtained according to tan β ═ ρ/L, and a grating pitch d can be obtained according to a grating equation sin β ═ λ/d, at which time a two-dimensional parameter (d) for each grating lattice can be established (d is a fixed parameter)₁，θ₁)、(d₂，θ₂)、(d₃，θ₃)……(d_N，θ_N)；

(5) From the grating pitch d of the N grating lattices, a matrix can be obtained as follows:

d₁，d₂，……………………d_n

d_n+1，d_n+2，………………d_2*n

………………………………

d_n*(n-1)+1，d_n*(n-1)+2，……d_n*n

calculating to obtain the maximum value d of d_maxAnd a minimum value d_minThe minimum value corresponds to a gray value of 0 and the maximum value corresponds to a gray value of 255, and according to the corresponding relationship, the values of N d can be mapped to another matrix G composed of gray values, and the matrix G constitutes a gray map as follows:

G₁，G₂，……………………G_n

G_n+1，G_n+2，………………G_2*n

………………………………

G_n*(n-1)+1，G_n*(n-1)+2，……G_n*n；

(6) from the angles θ of the N grating lattices, a matrix can be obtained as follows:

θ₁，θ₂，……………………θ_n

θ_n+1，θ_n+2，………………θ_2*n

………………………………

θ_n*(n-1)+1，θ_n*(n-1)+2，……θ_n*n

calculating to obtain the maximum value theta of theta_maxAnd minimum value theta_minThe minimum value corresponds to a gray value of 0 and the maximum value corresponds to a gray value of 255, and according to the corresponding relationship, the values of N θ can be mapped to another matrix H composed of gray values, and the matrix constitutes a gray map as follows:

H₁，H₂，……………………H_n

H_n+1，H_n+2，………………H_2*n

………………………………

H_n*(n-1)+1，H_n*(n-1)+2，……H_n*n；

(7) manufacturing an exposure unit according to the photoetching space frequency gray matrix G and the grating angle gray matrix H, wherein the size of the exposure unit is a square with the side length of n/R mm, R is the resolution of a photoetching image, and R is more than 10dpi and less than 50800 dpi;

(8) and (4) forming the exposure unit array in the step (7) into a designed size, manufacturing the exposure unit array on a photoetching offset plate through a photoetching process, and developing and electroplating to obtain the laser encryption information layer mould pressing plate.

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

1. the laser encryption anti-counterfeiting transfer paper is provided with the laser encryption information layer, the digital coding information grating structure is hidden in the laser encryption information layer, the encryption information is hidden under natural light, the transfer paper is irradiated by using handheld point light source equipment, the hidden information is presented, and a consumer judges the authenticity of a product by identifying the hidden information, so that the consumer can conveniently inquire the authenticity.

2. The invention is encrypted by a mathematical algorithm, has high anti-counterfeiting strength, is not easy to crack and forge, and increases the imitation difficulty.

3. The invention adopts new anti-counterfeiting characteristics, so that the anti-counterfeiting transfer paper has exclusivity.

4. The preparation method is scientific, reasonable, simple and feasible.

Drawings

Fig. 1 is a hidden pattern in embodiment 1 of the present invention;

FIG. 2 is a gray scale diagram corresponding to the matrix G in embodiment 1 of the present invention;

fig. 3 is a grayscale diagram corresponding to the matrix H in embodiment 1 of the present invention.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples, but the present invention is not limited to the following examples.

The methods are conventional methods unless otherwise specified. The starting materials are commercially available from the open literature unless otherwise specified.