Three-bond-containing Raman ink capable of realizing 3D printing as well as preparation method and application of three-bond-containing Raman ink

Abstract

The invention discloses three-bond-containing Raman ink capable of achieving 3D printing and a preparation method and application of the three-bond-containing Raman ink. The three-bond-containing Raman ink comprises a coloring agent, a binder, a cross-linking agent and a photoinitiator, the coloring agent is a polymer microsphere, and a branch chain of a polymer comprises a carbon-carbon three bond or a carbon-nitrogen three bond. The three-bond-containing Raman ink has a strong Raman scattering signal, is invisible to naked eyes, has a good invisible effect and good stability, and is not easy to imitate. Controllable arrangement of the Raman active polymer in a confinement space is achieved by means of the 3D printing technology, and a series of super Raman passwords are formed.

Description

Technical Field

[0001] The present invention belongs to the technical field of anti-counterfeiting and information security, and specifically relates to a 3D printable, three-bond Raman ink preparation and its application in anti-counterfeiting and information security. Background Art

[0002] In recent decades, the problem of counterfeit goods and information security has become increasingly serious, posing a major threat to multiple sectors and causing economic instability, public health hazards, and damage to government credibility. Undetectable, unforgeable, and long-lasting anti-counterfeiting measures are essential to maintaining the integrity and reputation of products, companies, and governments. Materials that combine anti-counterfeiting with information storage and traceability functions can effectively achieve anti-counterfeiting, traceability, and quality monitoring of goods. The whole chain controls product quality and safety, which is a powerful technical guarantee for the establishment of an integrity supervision mechanism in the new era. Anti-counterfeiting-traceability system: One type is traditional and mainly relies on laser-printed barcodes or QR codes for anti-counterfeiting or encryption; the other type is based on rapidly developing optical materials (especially fluorescence), with screen or inkjet printing as the preparation process, to achieve the manufacture and re-encryption of holographic images and texts for anti-counterfeiting. Analysis of the advantages and disadvantages of the above anti-counterfeiting technologies: Traditional anti-counterfeiting technology is simple to operate, has a low design threshold, and is extremely easy to read and imitate. It is difficult to adapt to the requirements of diversified and personalized effective anti-counterfeiting; in order to adapt to the needs of the information age, it is urgent to develop new optical material anti-counterfeiting and information storage technologies with sophisticated processes, diverse responses, massive information, and difficult imitation. Information storage provides a basis for the classification and traceability of diversified commodities. While vigorously developing anti-counterfeiting technology, research on information storage is also indispensable, and the anti-counterfeiting technology of optical materials and information storage complement each other. While new optical materials are used for information storage, they can also be used as emerging anti-counterfeiting materials. Optical information storage mainly relies on optically active materials as a medium to modulate light signals, including intensity (step grayscale value), wavelength (wavelength division multiplexing), time domain (time division multiplexing), etc. Various anti-counterfeiting technologies have been developed in the prior art, which significantly improve data security by using advanced encryption algorithms and more complex exposable ink materials. These releasable codes are usually made of fluorescent and other luminescent materials and are invisible under normal circumstances. They can only be seen with the naked eye after specific treatments, such as exposure to ultraviolet light or high temperatures, adding an extra layer of security. However, the visibility exposed after treatment can be studied and copied by sophisticated counterfeiters, reducing their long-term effectiveness. Summary of the invention

[0003] The present invention provides a 3D printable Raman ink containing three bonds, a preparation method and an application thereof, with the purpose of solving the problem that anti-counterfeiting labels in the prior art can be imitated. The anti-counterfeiting label 3D printed with the Raman ink containing three bonds provided by the present invention is invisible to the naked eye after any reading process, and requires special equipment to detect and read. Since it is extremely difficult to imitate or tamper with, it ensures safety.

[0004] The first aspect of the present invention provides a 3D printable triple-bond Raman ink, comprising:

[0005] A colorant, wherein the colorant is a polymer microsphere, and the side chain of the polymer contains a carbon-carbon triple bond or a carbon-nitrogen triple bond;

[0006] A binder, wherein the binder is a water-based acrylic resin;

[0007] A cross-linking agent, wherein the cross-linking agent is diethylene glycol ethyl ether acrylate;

[0008] Photoinitiators are used to initiate free radical polymerization reactions of crosslinkers, linkers, and colorants.

[0009] In some embodiments of the present invention, the particle size of the polymer microspheres is 100-200 nm; and / or the number average molecular weight of the polymer is 20,000-40,000; and / or the weight average molecular weight of the water-based acrylic resin is 2,000-4,000.

[0010] In some embodiments of the present invention, the mass ratio of the colorant, the binder, and the cross-linking agent is 1:1-2:0.3-0.5.

[0011] In some embodiments of the present invention, the water-based acrylic resin is polyacrylate and / or polyethylene glycol diacrylate; and / or the photoinitiator is 2,4,6-phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0012] In some embodiments of the present invention, the viscosity of the triple bond Raman ink is ≥6×10 5 mP·s, surface tension ≤50mN / m.

[0013] The second aspect of the present invention provides a method for preparing the above-mentioned 3D printable triple-bond Raman ink, comprising:

[0014] Providing polymer microspheres, wherein the side chains of the polymer contain carbon-carbon triple bonds or carbon-nitrogen triple bonds;

[0015] The polymer microspheres, linkers, crosslinkers and photoinitiators are dispersed in a solvent and the viscosity is adjusted to be more than 6×10 5 mP·s and a surface tension lower than 50 mN / m, a 3D printable triple-bond Raman ink is obtained.

[0016] A third aspect of the present invention provides application of the above-mentioned 3D printable triple-bond Raman ink in the field of anti-counterfeiting.

[0017] A fourth aspect of the present invention provides a method for manufacturing a product containing an anti-counterfeiting mark, comprising:

[0018] Using different Raman inks to print different parts of the anti-counterfeiting mark to form multiple anti-counterfeiting mark fragments; after printing, the multiple anti-counterfeiting mark fragments are combined into a complete anti-counterfeiting mark;

[0019] The Raman ink is the above-mentioned 3D printable triple-bond Raman ink, and the Raman shift of polymer microspheres is different between different Raman inks.

[0020] In some embodiments of the present invention, different Raman inks are used to print marking points on different anti-counterfeiting layers, and the marking points on each anti-counterfeiting layer are part of the anti-counterfeiting mark; after printing layer by layer, all the marking points form a complete anti-counterfeiting mark. During the printing process, the anti-counterfeiting layer is cured by ultraviolet light.

[0021] The present invention realizes the solidification and molding of various Raman inks in two-dimensional and three-dimensional space based on the pixel-by-pixel / layer-by-layer printing function of the 3D printer, and the three-dimensional structural pattern thereof is used for anti-counterfeiting code.

[0022] A fifth aspect of the present invention provides a product containing an anti-counterfeiting mark, comprising multiple anti-counterfeiting layers, each anti-counterfeiting layer being provided with marking points printed with different Raman inks, the marking points on each anti-counterfeiting layer being part of the anti-counterfeiting mark, and all the marking points forming a complete anti-counterfeiting mark.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Existing technologies cannot achieve the large-scale and super-capacity preparation of differentiated anti-counterfeiting labels, but 3D printing technology can automatically encrypt information and prevent counterfeiting in three-dimensional space, which will greatly expand the coding capacity.

[0025] (2) The triple-bond Raman ink provided by the present invention has a signal output that does not interfere with the Raman signal of the packaging material, facilitating spectral differentiation and rapid decryption.

[0026] (3) The Raman anti-counterfeiting and information encryption strategy provided by the present invention has good spectral stability and can be preserved for a long time, and is also convenient for it to be used as an anti-counterfeiting label for circulation with goods and repeated verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention.

[0028] Figure 1Schematic diagram of the preparation of 3D printable triple-bond Raman ink and its encryption and decryption for anti-counterfeiting and information security.

[0029] Figure 2 This is a field emission scanning electron microscope image of the polymer used in the present invention, wherein the polymer microspheres are 100 to 200 nm in size and are uniformly spherical. Figure 2 (a) to Figure 2 (f) The triple bond Raman signal is 2160cm -1 、2186cm -1 、2203cm -1 , 2227cm -1 、2241cm -1 、2260cm -1 of polymer microspheres.

[0030] Figure 3 This paper explores the optimization of the mixing ratio of each component in the triple-bond Raman ink and the spectral performance diagram of the ink. Figure 3 (a); Surface tension diagram of the reaction mixture with different ratios; Figure 3 (b); Viscosity diagram of the mixture after reaction at different ratios; Figure 3 (c) Comparison of Raman spectra of the formulated triple bond Raman ink and triple bond polymer; Figure 3 (d) Raman spectrum stability diagram of the formulated triple-bond Raman ink.

[0031] Figure 4 This is a test diagram of the stability and reliability of the printed pattern. Figure 4 (a): Actual picture of 3D printed multifunctional pattern; Figure 4 (b): Physical images of 3D printed QR codes on different substrates; Figure 4 (c): Research on the damage resistance of 3D printed patterns, including resistance to high temperature, UV, water, and erasure; Figure 4 (d): Continuous Raman imaging of printed QR code and repeated information verification comparison diagram; Figure 4 (e): 3D printed patterns based on reflection, fluorescence and Raman and their optical verification images; Figure 4 (f): 3D printed fluorescent pattern and its spectrum; Figure 4 (g): 3D printed Raman pattern and its spectrum; Figure 4 (h): Two types of Raman inks are used to print three-dimensional structures;

[0032] Figure 4 (i): Scanning electron microscopy images of planar and three-dimensional structural areas; Figure 4 (j): Raman spectra of two Raman inks used in the three-layer structure.

[0033] Figure 5Schematic diagram of the use of spectral, spatial, and logical properties for encryption of Raman inks. Figure 5 (a); Schematic diagram of three authentication keys: Raman code, space code, and 6-bit code; Figure 5 (b); Petal patterns printed by one or six triple-bond Raman inks and Raman spectra at different points of the pattern; Figure 5 (c); Schematic diagram of 6-bit code information encoding and decoding based on Raman spectroscopy.

[0034] Figure 6 Schematic diagram for constructing an anti-counterfeiting label based on three-dimensional embedded invisible Raman code. Figure 6 (a); Schematic diagram of printing the three selected Raman inks layer by layer; Figure 6 (b); Schematic diagram of making 3D anti-counterfeiting label; Figure 6 (c) A physical picture of the prepared three-dimensional anti-counterfeiting label; Figure 6 (b); Schematic diagram of the 3D Raman decryption strategy of the 3D anti-counterfeiting label; Figure 6 (e); Three-dimensional Raman imaging for decryption; Figure 6 (f); Diagram of the information decryption process of the invisible Raman code embedded in the three-dimensional anti-counterfeiting label. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range. Similarly, any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0037] It should be noted that, in the description of this article, unless otherwise specified, "above", "below" include the number, and the meaning of "multiple" in "one or more" is two or more. Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0038] In the description of this specification, the description with reference to the terms "any embodiment / method", "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0039] The above summary of the invention of the present invention is not intended to describe each disclosed embodiment or each implementation in the present invention. The following description more specifically illustrates exemplary embodiments. These embodiments can be used in various combinations. In each example, the enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0040] The present invention prepares a variety of polymer Raman tags containing triple bonds, which have the characteristics of "narrow band (1-2nm) single peak" with high sensitivity, high spectral resolution and no light interference of Raman signal molecules. The prepared triple-bond polymer is further used as a colorant for water-based ink and mixed with additives such as photocurable prepolymers to formulate a "Raman ink" containing triple bonds suitable for 3D printing. With the help of 3D printing technology, the controllable arrangement of Raman active polymers in a confined space is realized to form a series of super Raman codes. At the same time, based on the diversified design of "Raman ink", 3D printing can easily realize the printing of diverse graphics and texts on a variety of packaging substrates, thereby realizing spectral controllable splicing and encrypted coding in multi-dimensional space. The graphic information can be easily decoded using Raman spectrometers and imaging technology, and the differential coding of spectral information in graphics and texts is used to provide a new type of high-capacity anti-counterfeiting and traceability code for various types and diversified commodities, which is also a powerful technical guarantee for the establishment of a credit supervision mechanism in the new era.

[0041] Containing triple bond Raman ink:

[0042] The 3D printable triple-bond Raman ink provided by the present invention comprises:

[0043] A colorant, wherein the colorant is a polymer microsphere, and the side chain of the polymer contains a carbon-carbon triple bond or a carbon-nitrogen triple bond;

[0044] A binder, wherein the binder is a water-based acrylic resin;

[0045] A cross-linking agent, wherein the cross-linking agent is diethylene glycol ethyl ether acrylate;

[0046] Photoinitiators are used to initiate free radical polymerization reactions of crosslinkers, linkers, and colorants.

[0047] The colorant of the triple bond Raman ink provided by the present invention is a polymer microsphere formed by a polymer having a branched chain containing a carbon-carbon triple bond or a carbon-nitrogen triple bond. The carbon-carbon triple bond or the carbon-nitrogen triple bond has a significant Raman scattering signal. The Raman intensity of the polymer microsphere is 50 times greater than that of its monomer and 40 to 60 times greater than that of EdU ( Figure 2 b), therefore, the triple-bond Raman ink provided by the present invention has a stronger Raman scattering signal.

[0048] Raman scattering represents the vibrational characteristics of molecules, and its low cross section ensures that the Raman scattering signal is invisible to the naked eye, which is particularly suitable for invisible codes. The unique Raman spectrum of each molecule allows highly specific and personalized coding, while the stability of the Raman signal ensures resistance to photobleaching, environmental changes and other forms of degradation. Therefore, the triple-bond Raman ink provided by the present invention ensures high security and durability.

[0049] In some embodiments of the present invention, the particle size of the polymer microspheres is 100-200 nm; and / or the number average molecular weight of the polymer is 20,000-40,000; and / or the number average molecular weight of the water-based acrylic resin is 2,000-4,000. Preferably, the number average molecular weight of the polymer is 25,000-35,000, and the particle size of the polymer microspheres is 150-200 nm.

[0050] In some embodiments of the present invention, the mass ratio of the colorant, the binder, and the cross-linking agent is 1:1-2:0.3-0.5.

[0051] In some embodiments of the present invention, the amount of polyethylene glycol diacrylate added is 20wt-30wt% of the triple bond Raman ink, and the amount of acrylic resin added is 25wt-35wt% of the triple bond Raman ink. The viscosity of the triple bond Raman ink is ≥6×10 5 mP·s, and has good printing performance when the surface tension is ≤50mN / m. The purpose of adding polyethylene glycol diacrylate 700 (PEGD) to the triple-bond Raman ink of the present invention is to adjust the surface tension of the triple-bond Raman ink, and the purpose of adding polyacrylate (PAA) is to increase the viscosity of the triple-bond Raman ink. The addition amount of polyethylene glycol diacrylate in the triple-bond Raman ink of the present invention is controlled between 20wt% and 30wt%, and the addition amount of polyacrylate is controlled between 25wt% and 35wt%, the addition amount of polyethylene glycol diacrylate is 20wt%, and the addition amount of acrylic resin is 30wt%.

[0052] In some embodiments of the present invention, the photoinitiator is 2,4,6-phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. The photoinitiator can initiate a polymerization reaction under ultraviolet light to solidify the triple-bond Raman ink.

[0053] The present invention adopts Raman shift in the Raman silent zone (1800-2800cm -1 ) polymer microspheres, when using a variety of Raman shifts in the Raman silent region (1800 ~ 2800cm -1 ) polymer microspheres, the spectral line combination can be used to encode complex information, which is more secure and the code is extremely difficult to imitate or tamper with. Therefore, the triple bond Raman ink of the present invention can become an ideal candidate for high-capacity invisible anti-counterfeiting materials by adding more color options as an additional security level.

[0054] Preparation method of triple bond Raman ink:

[0055] The present invention provides a method for preparing a 3D printable triple-bond Raman ink, comprising:

[0056] Providing polymer microspheres, wherein the side chains of the polymer contain carbon-carbon triple bonds or carbon-nitrogen triple bonds;

[0057] The polymer microspheres, linkers, crosslinkers and photoinitiators are dispersed in a solvent and the viscosity is adjusted to be more than 6×10 5 mP·s and a surface tension lower than 50 mN / m, a 3D printable triple-bond Raman ink is obtained.

[0058] In some embodiments of the present invention, providing polymer microspheres includes: using emulsion polymerization to polymerize monomers containing carbon-carbon double bonds and carbon-carbon triple bonds or carbon-nitrogen triple bonds into polymer microspheres. The size of polymer microspheres prepared by emulsion polymerization is uniform and controllable, and the Raman signal intensity of the triple bond is higher than that of monomers containing carbon-carbon double bonds and carbon-carbon triple bonds or carbon-nitrogen triple bonds at the same time. Providing polymer microspheres specifically includes: in an oxygen-free atmosphere, polymerizing monomers containing carbon-carbon double bonds and carbon-carbon triple bonds or carbon-nitrogen triple bonds in an emulsion containing an emulsifier and an initiator to obtain polymer microspheres. The polymerization temperature is 60 to 80°C, and the polymerization time is 1 to 3 hours. Preferably, the oxygen-free atmosphere is an inert gas atmosphere or a nitrogen atmosphere. The emulsifier is an amphiphilic surfactant, the amphiphilic surfactant is sodium dodecylbenzene sulfonate and / or sodium dodecyl sulfate, and the initiator is potassium persulfate and / or azobisisobutyronitrile.

[0059] The monomers containing both carbon-carbon double bonds and carbon-carbon triple bonds or carbon-nitrogen triple bonds used in the present invention contain triple bonds and double bonds, the triple bonds include alkynyl (i.e., carbon-carbon triple bonds) and cyano (i.e., carbon-nitrogen triple bonds), and the alkynyl groups are capped and protected by other groups, the triple bonds provide encrypted Raman signal sources, and the double bonds provide polymer potential. Under the condition of the presence of an initiator, the double bonds on the monomer participate in the reaction and quickly polymerize into polymer microspheres. In some embodiments of the present invention, the monomer containing both carbon-carbon double bonds and carbon-carbon triple bonds or carbon-nitrogen triple bonds is 4-vinyl-benzonitrile or acrylonitrile.

[0060] In some embodiments of the present invention, the polymer microspheres, the linker, the crosslinker, and the photoinitiator are dispersed in a solvent in the following manner: the polymer microspheres, the crosslinker, and the photoinitiator are dispersed in an aqueous solution of the linker.

[0061] application:

[0062] The colorant in the 3D printable triple-bond Raman ink provided by the present invention is an invisible substance that cannot be observed by the naked eye. Each molecule has a unique Raman spectrum, and highly specific and personalized codes can be prepared. Therefore, the anti-counterfeiting label made with it is difficult to imitate and has high security. In addition, the Raman signal has good stability and high resistance to photobleaching, environmental changes and other forms of degradation. The anti-counterfeiting label made with the triple-bond Raman ink of the present invention can exist stably for a long time.

[0063] like Figure 1As shown, the present invention prepares polymer microspheres from monomer small molecules containing triple bonds, and then uses the polymer microspheres as colorants, adds cross-linking agents, connectors, photoinitiators, etc. to formulate 3D printable Raman ink containing triple bonds, and uses a 3D printer to automatically prepare a three-dimensional structure code for information encryption and anti-counterfeiting use.

[0064] For example, three-key Raman ink can be layered and embedded into a multi-layer invisible anti-counterfeiting solution through 3D printing, and two-dimensional plane / three-dimensional space patterns (mainly involving two-dimensional codes and three-dimensional structure codes representing information) can be printed in the 3D printing system. Multiple inks are selected for alternate printing strategies, and the Raman ink is squeezed out of the nozzle (60mm) by controlling the air pressure at a speed of 6s / drop, and printed according to the designed pattern. During the 3D printing process, the printed structure is cured by UV light at room temperature (wavelength of 405nm, power of 40mW).

[0065] Manufacturing method of products containing anti-counterfeiting marks:

[0066] The manufacturing method of the product containing the anti-counterfeiting mark provided by the present invention comprises: using different Raman inks to print different parts of the anti-counterfeiting mark to form a plurality of anti-counterfeiting mark fragments; after printing, the plurality of anti-counterfeiting mark fragments are combined into a complete anti-counterfeiting mark; the Raman ink is the above-mentioned 3D printable three-bond Raman ink, and the Raman shift of the polymer microspheres is different between different Raman inks.

[0067] The anti-counterfeiting mark is a two-dimensional anti-counterfeiting pattern or a three-dimensional anti-counterfeiting pattern.

[0068] In some embodiments of the present invention, different Raman inks are used to print marking points on different anti-counterfeiting layers, and the marking points on each anti-counterfeiting layer are part of the anti-counterfeiting mark; after printing layer by layer, all the marking points form a complete anti-counterfeiting mark. During the printing process, the anti-counterfeiting layer is cured by ultraviolet light. Specifically, the anti-counterfeiting layer is cured by ultraviolet light (405nm light, 40mW) at room temperature, and each layer is cured.

[0069] The method embeds Raman ink into multiple layers of invisible anti-counterfeiting codes. These 3D invisible labels have excellent visual transparency, high coding capacity and extraordinary stability. By adopting a multi-layer strategy in 3D printing, Raman ink forms multiple layers of visually imperceptible QR codes that cannot be deciphered when examined individually, and only reveal their encrypted information when all layers are combined, meeting the development requirements of designing highly difficult anti-counterfeiting labels and large-capacity coding.

[0070] The technical solution of the present invention is described in detail below through specific embodiments:

[0071] 4-vinyl-benzonitrile, acrylonitrile, diethylene glycol ethyl ether acrylate, polyacrylate (PAA, Mw=3000, 50% aqueous solution) and 2,4,6-phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide used in the following examples were purchased from Aladdin Reagent Co., Ltd. (Shanghai, China). Polyethylene glycol diacrylate (PEGD), sodium dodecyl sulfate, potassium persulfate (KPS) were purchased from Sinopharm Chemical Reagent Co., Ltd. (China). All other chemical reagents used in the present invention were of analytical grade, obtained from commercial suppliers, and used without further purification unless otherwise specified.

[0072] Example 1: Synthesis of Raman-active polymers

[0073] 50 mg of 4-vinyl-benzonitrile (2227 cm -1 ) or acrylonitrile (2241cm -1 ) were dissolved in 10 mL of H2O and placed in 50 mL round-bottom flasks. Subsequently, 1 mL of sodium dodecyl sulfate (2 mg / mL in H2O solution) was added to the round-bottom flask and homogenized after stirring (600 r / min) at room temperature for 30 min. When the system was heated to 70 °C, 250 μL of KPS solution (10 mg / mL in H2O solution) was added to initiate the reaction and polymerized at 70 °C for 2 h. Note that the reaction system was always protected by nitrogen to avoid oxygen consumption of the initiator during this process. After the reaction, the reaction system was naturally cooled to room temperature, and the synthesized polymer latex was purified with distilled water through a dialysis bag (molecular weight cutoff 3500 Da) for three days, and fresh distilled water was replaced every 6 hours to remove excess surfactants and other residues. Finally, the purified latex was stored at 4 °C for further use and characterization. The polymer of 4-vinyl-benzonitrile was designated as P1, and the polymer of acrylonitrile was designated as P2.

[0074] The morphology of polymers P1 and P2 was investigated using a field emission scanning electron microscope (FE-SEM, Zeiss Sigma, Germany) at an accelerating voltage of 10.0 kV. The hydrodynamic diameters were measured using a dynamic light scattering instrument (DLS, Zetasizer Nano ZSP, UK). Figure 2 (d) and Figure 2 (e) shows that the sizes of polymers P1 and P2 are about 150-200 nm, with similar particle morphology and monodisperse diameters. These measured values ​​are consistent with the hydrodynamic diameter results.

[0075] The molecular weights of polymers P1 and P2 were characterized by gel permeation chromatography (GPC). The number average molecular weights (Mn) of polymers P1 and P2 were 26190 and 33357, the weight average molecular weights (Mw) were 73332 and 71183, and the peak molecular weights (Mp) were 68935 and 81365, respectively. The polydispersity indexes (PDI) were 2.800 and 2.394, respectively, indicating that the present invention obtained high-quality polymers with molecular aggregation through this free radical polymerization strategy. At 2227 cm -1 and 2241cm -1 At 1.5 nm, a clear Raman shift can be observed. In addition, the polymer exhibits sharp Raman peaks with narrow linewidth (<2 nm) and no spectral crosstalk. Positively, the polymer shows stronger triple-bond Raman scattering than its monomer (50 times larger) and EdU (40-60 times larger), indicating that molecular aggregation can effectively enhance the Raman signal.

[0076] Example 2: Synthesis of triple bond Raman ink

[0077] Under ultrasonic dispersion, 2.0 g of polyacrylate (Mw=3000, mass fraction 50%) aqueous solution was added to a 50 mL flask, and then 3.0 g of polymer P1 or P2, 2 g of polyethylene glycol diacrylate 700, 1 g of diethylene glycol ethyl ether acrylate and 10 mg of 2,4,6-phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide were mixed with the polyacrylate aqueous solution to obtain a triple bond Raman ink.

[0078] The purpose of adding polyethylene glycol diacrylate 700 (PEGD) to the triple bond Raman ink is to adjust the surface tension of the triple bond Raman ink, such as Figure 3 As shown in (a), the present invention adjusts the addition amount of PEGD to 10wt%, 20wt%, and 30wt% of the triple-bond Raman ink, and finds that when the addition amount of PEGD is 20wt%, the triple-bond Raman ink can stably form droplets, meeting the requirements of 3D printing. When the addition amount of PEGD is 10wt%, the triple-bond Raman ink can form droplets, but the stability is poor.

[0079] The purpose of adding polyacrylate (PAA) to the triple bond Raman ink is to increase the viscosity of the triple bond Raman ink and prevent nozzle clogging and ensure continuous filament extrusion, e.g. Figure 3 As shown in (b), the present invention adjusts the addition amount of PAA to 10wt%, 20wt%, and 30wt% of the triple-bond Raman ink. When the addition amount of PAA is 30wt%, the triple-bond Raman ink has the best 3D printing performance.

[0080] The triple-bond Raman ink containing 20 wt% PEGD and 30 wt% PAA was placed in the dark for use, and the subsequent experiments used the triple-bond Raman ink.

[0081] Example 3: 3D printing experiment

[0082] The 3D printing of the three-bond Raman ink was performed using a pneumatic 3D printer. The multi-dimensional code was 3D printed using a microelectromechanical printer. Prior to printing, the upper surface of the 3D printed substrate was treated with a vacuum plasma cleaner (cleaning at 70Pa, 200mW for 300 seconds) to impart hydrophilicity and allow water to diffuse. In order to take advantage of these three-bond Raman inks for 3D printing, various patterns were prepared in advance using Auto CAD drawing software and then imported into the 3D printing system to generate the printing route. The three-bond Raman ink was extruded from the nozzle (60 mm) by air compressor control at appropriate pressure to obtain a speed of 6 seconds / drop, and the designed pattern was automatically written according to the user-defined route, using 60 mm per pixel. During the 3D printing process, UV curing (405nm light, power of 40mW) was performed in the printed structure at room temperature. In order to improve the curing performance, a post-UV curing process was further performed and the printed structure was treated with 405nm light at 40mW for 10 minutes. Finally, the 3D printed structures were ultrasonically cleaned in 10 wt% NaCl solution for 2 min to remove the uncured raw materials. The pneumatic / optical control of the continuous 3D printing process was investigated by using a digital camera to acquire real-time images.

[0083] To demonstrate 3D printing automation, the present invention pre-designed and successfully printed various patterns, including circles, squares, complex shapes, and QR codes ( Figure 4 a). These inks show broad printing applicability on traditional packaging materials such as paper, metal, glass and flexible films ( Figure 4 b), enhancing their potential use in anti-counterfeiting labels and information storage. The cured patterns showed strong resistance to high temperatures (100°C), no damage after being immersed in water for one hour, and erasure resistance ( Figure 4 c). In addition, the present invention verifies imaging stability and information traceability. The printing process completed in a few minutes using the machine and ink of the present invention produces high accuracy, which is proven by the traceability when scanning the prepared QR code with a mobile phone. Three-bond Raman scattering is the hidden key for information authentication, and the QR bright image uses the characteristic three-bond peak to perfectly superimpose with the Raman color ( Figure 4 d). Raman imaging area and bright images acquired based on the video of Easy Map show that more than 90% of similar Raman images were detected after five repeated Raman imaging with long laser irradiation, demonstrating the ultra-stable potential of these Raman inks for reliable information traceability.

[0084] To demonstrate the potential of 3D encryption and decryption, the present invention verifies the 3D printing and 3D Raman detection capabilities of anti-counterfeiting labels ( Figure 4 e- Figure 4 j) In Figure 4 e- Figure 4 g, the present invention conducted comparative tests using 3D printers with colorimetric, fluorescent and Raman pigments. The colorimetric and fluorescent pigments had poor permeability and peak recognition in the overlapping area, while the Raman markers showed distinct peaks, highlighting their superior performance. In addition, the two Raman inks ( Figure 4 h). The printed pattern exhibits excellent light transmittance, and the front and cross-sectional FE-SEM images show distinct polymer nanoparticles, ensuring 3D Raman detection ( Figure 4 i). As expected, different triple bond Raman signals were detected in different layers, and Raman signals were found alternately in the thickness range of nearly 1 mm ( Figure 4 j). This confirms the potential of 3D writing technology for controllably modulating triple-bond Raman scattering and suggests that 3D detection capability can provide effective decryption.

[0085] Example 4: Automatic multi-color Raman pattern printing and code construction

[0086] As one of the information carriers, important information can be stored and hidden in the pattern. The present invention designs patterns based on various physical stimuli, including spectral, spatial and logical properties, which can be used for effective verification and generate multiple unpredictable keys from the same pattern ( Figure 5 a). Using the Raman inks of the present invention, centimeter-sized flower patterns can be easily printed on 2D surfaces using one or six Raman inks ( Figure 5 b). The colorful flower pattern indicates that the encoding capacity increases with the number of pixels. The Raman image of the flower pattern shows the typical triple bond Raman signal at 2227 cm1.

[0087] In order to explore the application of Raman ink in information storage, the inventors designed a complex system using binary coding for encryption. Six kinds of Raman ink, representing binary "1" and "0", encode, store and decode information. For example, "111111" comes from the simultaneous presence of Raman signals at 2160, 2186, 2203, 2227, 2241 and 2260cm1, while "000000" means they do not exist. This binary coding is converted into a 6-bit code for information encryption, such as "I love WTU" ( Figure 5 c). Information is decrypted by matching the spectrum output with the corresponding 6-digit code, thus enhancing identity security and difficulty of impersonation. This is the first time that triple bond Raman ink has been used for secure information encryption with a 6-digit code.

[0088] Example 5: 3D invisible embedded Raman code generated by layer-by-layer printing

[0089] The invisible cross-layer code is composed of three types of single-layer Raman QR codes, which are printed separately and verified by Raman imaging based on the characteristic peaks of 2160, 2186 and 2227 cm1. Figure 6 As shown in Figure 5, these Raman micrographs can be scanned with a mobile phone application to read the coded information on the mobile phone showing the web pages of “Wuhan University”, “Wuhan University Graphic Communication, Printing and Packaging Research Center” and “Shenlab”.

[0090] The 3D invisible embedded code was created by alternating layers of printing with three different Raman inks (2160, 2186 and 2160, 2227 cm). Each layer of ink was printed and stacked on top of the previous layer after photocuring. A total of six rounds of printing were performed to produce the final code. In each layer, the encoding logic of each pixel was defined as follows: "1" for ink jetting and "0" for no jetting (Layer 1). The process was then repeated with another Raman ink for the next layer (Layer 2). Although the single-layer codes are printed at the same time, the information is distributed on different layers due to the inconsistent thickness of the previous encoding layer. Therefore, the correct code is "hidden" in different layers and can only be traced when the layers are combined ( Figure 6 e). Scanning each layer of code individually will not produce the correct information ( Figure 6 f). It is noteworthy that each Raman image in the 3D pattern taken from different layers and different Raman channels exhibits unique characteristics. Image similarity analysis shows that the similarity between different Raman images is only about 50%. This low image similarity will greatly prevent counterfeiters from imitating. This 3D Raman integrated encryption system is not only invisible to the naked eye after reading processing, but also makes single-layer decoding invalid, requiring a combination of multiple layers to unlock the encryption, ensuring the highest degree of security due to the exceptional difficulty of imitation.

[0091] Example 6: Physical Unclonable Function (PUF) Generation for Anti-Counterfeiting

[0092] The present invention found that the red image gradually darkens with the change of depth, the green image gradually brightens, and the blue image first brightens and then darkens, which is very consistent with the 3D printing order in the 3D code. Inspired by the different Raman images in different layers in this 3D pattern, the PFU system can be further generated by ID cards with red, green, and blue codes with different Raman channels and unknown spatial positions ( Figure 6 d), which is the highest level in the current anti-counterfeiting field.

[0093] The application of this 3D label in the supply chain is first manufactured by manufacturers and distributors, and then sold to end users for packaging. The product is labeled as a unique ID code after leaving the manufacturer. Of course, there is a public database of manufacturers and labels for supervision first. Subsequently, the correct Raman code can be authenticated throughout the product circulation process, and then digitized by software and stored in the public database. In the future, with the upgrade of the mobile phone Raman system, the end user of the present invention will also be able to easily verify each product in a personal database that is closely related to the public database. If the digital information does not match any information in the database, it will be considered a counterfeit.

[0094] Embodiment 7:

[0095] Although spectral overlap may occur in the 400 to 1800 cm-1 region due to various ink compositions and substrates (e.g., paper, glass, flexible films), the triple bond Raman inks effectively write and express Raman information on common substrates in the 1800 to 2800 cm-1 region without interference. The present invention then characterized the environmental stability of the Raman inks. After multiple light treatments for more than one month, the Raman spectra of all Raman inks remained stable, showing excellent photostability compared to other optical materials. These Raman active polymers showed greater spectral stability than SERS tags and common fluorescent dyes.

[0096] The above is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A 3D printable triple-bond Raman ink, the triple-bond Raman ink comprising: A colorant, wherein the colorant is a polymer microsphere, and the side chain of the polymer contains a carbon-carbon triple bond or a carbon-nitrogen triple bond; A binder, wherein the binder is a water-based acrylic resin; A cross-linking agent, wherein the cross-linking agent is diethylene glycol ethyl ether acrylate; Photoinitiators are used to initiate free radical polymerization reactions of crosslinkers, linkers, and colorants.

2. The 3D printable triple-bond Raman ink according to claim 1, characterized in that: The particle size of the polymer microspheres is 100 to 200 nm; and / or, The number average molecular weight of the polymer is 20,000 to 40,000; and / or, The weight average molecular weight of the waterborne acrylic resin is 2000 to 4000; and / or, The mass ratio of the colorant, the binder and the cross-linking agent is 1:1-2:0.3-0.

5.

3. The 3D printable triple-bond Raman ink according to claim 1, characterized in that: The water-based acrylic resin is polyacrylate and / or polyethylene glycol diacrylate; The photoinitiator is 2,4,6-phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

4. The 3D printable triple-bond Raman ink according to claim 1, characterized in that: The viscosity of the triple bond Raman ink is ≥6×10 5 mP·s, surface tension ≤50mN / m.

5. The method for preparing a 3D printable triple-bond Raman ink according to any one of claims 1 to 4, characterized in that: include: Providing polymer microspheres, wherein the side chains of the polymer contain carbon-carbon triple bonds or carbon-nitrogen triple bonds; The polymer microspheres, linkers, crosslinkers and photoinitiators are dispersed in a solvent and the viscosity is adjusted to be more than 6×10 5 mP·s and a surface tension lower than 50 mN / m, a 3D printable triple-bond Raman ink is obtained.

6. The method for preparing a 3D printable triple-bond Raman ink according to claim 5, characterized in that: Providing polymer microspheres comprises: using emulsion polymerization to polymerize monomers containing both carbon-carbon double bonds and carbon-carbon triple bonds or carbon-nitrogen triple bonds into polymer microspheres.

7. Use of the 3D printable triple-bond Raman ink according to any one of claims 1 to 4 in the field of anti-counterfeiting.

8. A method for manufacturing a product containing an anti-counterfeiting mark, characterized in that: include: Using different Raman inks to print different parts of the anti-counterfeiting mark to form multiple anti-counterfeiting mark fragments; After printing is completed, multiple anti-counterfeiting mark fragments are combined into a complete anti-counterfeiting mark; The Raman ink is the 3D printable triple-bond Raman ink as claimed in claim 1, and the Raman shift of the polymer microspheres is different between different Raman inks.

9. The method for manufacturing a product with an anti-counterfeiting mark according to claim 8, characterized in that: Different Raman inks are used to print marking points on different anti-counterfeiting layers, and the marking points on each anti-counterfeiting layer are part of the anti-counterfeiting mark; after printing layer by layer, all the marking points form a complete anti-counterfeiting mark.

10. A product containing an anti-counterfeiting mark, characterized in that: It comprises multiple anti-counterfeiting layers, each of which is provided with marking points printed with different Raman inks. The marking points on each anti-counterfeiting layer are part of the anti-counterfeiting mark, and all the marking points constitute a complete anti-counterfeiting mark.

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