阅读说明：本技术 激光加密防伪转移膜及其制备方法 (Laser encrypted anti-counterfeiting transfer film and preparation method thereof ) 是由 张磊 张毅 张方伟 李涛 王庆林 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膜及其制备方法。所述的防伪转移膜包括从上到下依次设置的PET基膜层、转移涂层、激光加密信息层、铝层、耐碱光油层和表涂层,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膜,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膜,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 a laser encryption anti-counterfeiting transfer film and a preparation method thereof. The anti-counterfeiting transfer film comprises a PET (polyethylene terephthalate) base film layer, a transfer coating, a laser encryption information layer, an aluminum layer, an alkali-resistant gloss oil layer and a surface 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 film 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 film 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. A laser encryption anti-counterfeiting transfer film is characterized in that: the PET-based film comprises a PET-based film layer, a transfer coating, a laser encryption information layer, an aluminum layer, an alkali-resistant gloss oil layer and a surface 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.

2. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: the transfer coating is a transferable thermoplastic acrylic resin layer, and the dry coating amount of the transfer coating is 0.8-1.6g/m²The transfer coating was peeled from the PET base film with 3M tape and separation was carried out at any speed.

3. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: the laser encrypted information layer is internally hidden with digital coding information.

4. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: 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.

5. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: the hidden information of the laser encryption information layer comprises characters, letters, numbers, symbols or figures.

6. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: the thickness of the aluminum layer is

7. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: the dry coating amount of the alkali-resistant gloss oil layer is 0.2-1g/m²。

8. The laser encryption anti-counterfeiting transfer film according to claim 1, characterized in that: the surface coating has a dry coating amount of 0.2-0.6g/m²。

9. A method for preparing a laser encryption anti-counterfeiting transfer film according to 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) attaching an aluminum layer on the laser encrypted information layer;

(5) printing a local alkali-resistant gloss oil layer on the aluminum layer;

(6) washing off or partially washing off the aluminum layer of the part which is not printed with the alkali-resistant varnish by using alkali liquor;

(7) washing with water;

(8) coating a surface coating on the alkali-resistant gloss oil layer;

(9) and cutting into required sizes by using a splitting machine.

10. The preparation method of the laser encryption anti-counterfeiting transfer film 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 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

maximum of d is calculatedValue 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 a laser encryption anti-counterfeiting transfer film and a preparation method thereof.

Background

The anti-counterfeiting transfer film can directly transfer holographic information to a packaging stock, and is commonly used for packaging cigarette packets, wine packets, cosmetics, medicines, high-grade gifts and the like. The transfer film on the market at present has simple structure and single function, and is easy to forge.

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, and many consumers cannot use the anti-counterfeiting features to identify the authenticity.

Chinese patent CN101138930A discloses a method for manufacturing a laser decorative plastic plate and a special laser holographic transfer film, the method comprises the following steps: firstly, manufacturing a laser holographic transfer film; and secondly, placing the laser holographic transfer film into a metal mold for injection molding. The special laser holographic transfer film comprises a plastic film substrate, a holographic information layer and a reflecting layer, and is characterized in that: a release layer is arranged between the plastic film substrate and the holographic information layer. The invention combines the laser holographic technology and the in-mold molding (IMD) technology to simultaneously complete the laser holographic pattern transfer and the injection molding of the plastic piece, greatly reduces the working procedures and working hours, saves the cost, avoids the difficulty of forming the holographic pattern on the plastic plate with the complicated three-dimensional shape, and is suitable for large-scale production. 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 a laser encryption anti-counterfeiting transfer film 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 film 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 film comprises a PET (polyethylene terephthalate) base film layer, a transfer coating, a laser encryption information layer, an aluminum layer, an alkali-resistant gloss oil layer and a surface 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 transfer coating is a transferable thermoplastic acrylic resin layer, and the dry coating amount of the transfer coating is 0.8-1.6g/m²。

The transfer coating was peeled from the PET base film with 3M tape and was separated at any speed.

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

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 thickness of the aluminum layer is

The dry coating amount of the alkali-resistant gloss oil layer is 0.2-1g/m²Effectively protecting the covered aluminum layer from being washed away by alkali liquor.

The surface coating has a dry coating amount of 0.2-0.6g/m²The laser encryption information without the aluminum layer part is covered, the laser encryption information of the aluminum layer part is reserved, and the imitation difficulty is increasedAnd anti-counterfeiting effect.

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

(1) selecting a single-side corona PET base film with the thickness of 12-28 mu M, coating a transfer coating on the corona surface, and separating the transfer coating from the PET base film at any speed by peeling with a 3M adhesive tape;

(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) an aluminum layer is attached on the laser encryption information layer, and the aluminum layer is mainly used for protecting the laser encryption information layer from being damaged and improving the brightness of the transfer film;

(5) printing a local alkali-resistant gloss oil layer on the aluminum layer;

(6) washing off or partially washing off the aluminum layer of the part which is not printed with the alkali-resistant varnish by using alkali liquor;

(7) washing with water to remove alkali liquor attached to the membrane;

(8) coating a surface coating on the alkali-resistant gloss oil layer, so that laser encryption information of an aluminum layer part is reserved, and laser encryption information of an aluminum layer-free part is covered to form a transfer film with laser encryption information locally, and the imitation difficulty and the anti-counterfeiting effect are increased;

(9) and cutting into required sizes by using a splitting machine.

In the step (5), the alkali-resistant gloss oil layer can be in any combination form such as independent alkali-resistant gloss oil, combination of the alkali-resistant gloss oil and printing color paste, combination of the alkali-resistant gloss oil and matte powder and the like, and the printing patterns can be in any form such as characters, numbers, LOGO and the like.

In the step (6), the degree of washing away the aluminum layer is controlled by the vehicle speed, the temperature of the alkali liquor and the pH value of the alkali liquor, wherein the alkali liquor is NaOH aqueous solution, the pH value is 9-11, and the temperature of the alkali liquor is controlled at 40-70 ℃.

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 film 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 film 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.

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 a new anti-counterfeiting characteristic, so that the anti-counterfeiting transfer film 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.