A flexible water-based scratch-off ink, its preparation method and application

Abstract

The present application belongs to the technical field of printing, and particularly relates to a kind of soft plate water-based scratch-off ink and its preparation method and application. The soft plate water-based scratch-off ink includes scratch-off black water-based ink and scratch-off white water-based ink. The scratch-off black water-based ink includes: 35-50 parts of water-based resin; 35-50 parts of pigment; 2-4 parts of wetting agent; 0.5-3 parts of defoaming agent; 0.5-1.5 parts of slip aid; 10-30 parts of deionized water. The scratch-off white water-based ink includes: 35-50 parts of titanium white powder; 5-15 parts of styrene-acrylic emulsion; 15-30 parts of water-based polyurethane resin; 0.5-3.5 parts of dispersing agent; 2-4 parts of wetting agent; 0.5-3 parts of defoaming agent; 2-5 parts of slip aid; 10-20 parts of deionized water. The present application solves the problem of poor scratch-off rollability of instant ticket products, and the problem of ink residue and dirty hands when scratch-off by the purchaser, and provides a more ideal solution for instant ticket products.

Description

Technical Field

[0001] This invention belongs to the field of printing technology, specifically relating to a flexographic water-based scratch-off ink, its preparation method, and its application. Background Technology

[0002] The ink system for the scratch-off area of ​​instant lottery tickets typically includes, from bottom to top: base ink, interference pattern, coding ink, UV barrier ink, scratch-off ink, and four-color or spot color inks. The scratch-off black ink layer, scratch-off white ink layer, and surface color image printed on the UV barrier ink are collectively referred to as the scratch-off layer. The scratch-off layer is one of the core technologies of instant lottery ticket printing, and its key lies in the performance of the two functional inks: scratch-off black and scratch-off white. The main function of these two inks is to cover the data information under the UV barrier ink to ensure the security of the instant lottery ticket information, while also possessing good scratch-off performance and a certain degree of scratch resistance. In addition, the scratch-off ink must also have good film-forming properties, so that the ink layer after scratching can be rolled up, avoiding ink residue and messy hands, and improving the user experience.

[0003] Scratch-off black ink and scratch-off white ink each have different performance requirements. Besides high hiding power and good film-forming properties, scratch-off black ink also needs excellent compatibility with UV release oil, including good leveling and strong adhesion on the release oil. Scratch-off white ink, on the other hand, needs strong scratch resistance and anti-blocking properties to improve the durability and quality of instant scratch-off tickets.

[0004] Several patents in the prior art have researched and improved scratch-off inks. For example, Chinese patent CN110791144A discloses a scratch-off water-based gray ink for screen printing and its preparation method; Chinese patent CN104774500A discloses a water-based flexographic scratch-off white ink and its preparation method and application; and Chinese patent CN106867307A discloses a method for preparing a water-based black scratch-off ink. However, these scratch-off inks still have shortcomings in practical applications. For example, the rollability of the scratch-off ink layer is poor, resulting in ink residue that easily soils hands and affects the user's scratch-off experience. In addition, these inks perform poorly under high-speed printing conditions, which is not conducive to improving the production efficiency of enterprises. Therefore, developing scratch-off inks with better performance has become an urgent need in the field of instant ticket printing. Summary of the Invention

[0005] To address at least one of the problems in existing technologies, this invention provides a flexographic water-based scratch-off ink, its preparation method, and its application. This invention achieves complementary performance advantages through the optimized and synergistic design of the black and white water-based scratch-off ink formulations in the instant lottery ticket scratch-off system. Addressing the issues of poor rollability and ink residue and messy hands for lottery buyers when scratching instant lottery tickets, the scratch-off ink technology of this invention significantly improves these shortcomings, providing a more ideal solution for instant lottery ticket products.

[0006] A flexographic water-based scratch-off ink includes a scratch-off black water-based ink and a scratch-off white water-based ink; wherein, the scratch-off black water-based ink, by weight, comprises the following components:

[0007] 35-50 parts of water-based resin;

[0008] 35-50 parts pigment;

[0009] 2-4 parts wetting agent;

[0010] Defoamer 0.5-3 parts;

[0011] 0.5-1.5 parts of slippery additive;

[0012] 10-30 parts deionized water;

[0013] The waterborne resin is composed of waterborne polyurethane resin, styrene-acrylic resin and waterborne acrylic resin in a mass ratio of (5-15):(15-30):(10-20);

[0014] The scratch-off water-based ink, by weight, comprises the following components:

[0015] 35-50 parts titanium dioxide;

[0016] 5-15 parts of styrene-acrylic emulsion;

[0017] 15-30 parts of waterborne polyurethane resin;

[0018] Dispersant 0.5-3.5 parts;

[0019] 2-4 parts wetting agent;

[0020] Defoamer 0.5-3 parts;

[0021] 2-5 parts of slippery additive;

[0022] 10-20 parts deionized water.

[0023] Preferably, the scratch-off black water-based ink comprises, by weight, the following components:

[0024] 35-45 parts of water-based resin;

[0025] 35-43 parts pigment;

[0026] 2.5-3 parts wetting agent;

[0027] 0.5-1.5 parts of defoamer;

[0028] 1-1.2 parts of slippery additive;

[0029] 15-17.8 parts of deionized water.

[0030] Preferably, the scratch-off water-based ink comprises, by weight, the following components:

[0031] 35-45 parts titanium dioxide;

[0032] 10-15 parts of styrene-acrylic emulsion;

[0033] 20-29 parts of waterborne polyurethane resin;

[0034] Dispersant 2.5-3 parts;

[0035] 2.5-3 parts wetting agent;

[0036] 1.5-3 parts defoamer;

[0037] 3-4 parts of slippery additive;

[0038] 10.5-14.5 parts deionized water.

[0039] The inventors have discovered that using a water-based resin composed of water-based polyurethane resin, styrene-acrylic resin, and water-based acrylic resin can significantly improve the rollability of scratch-off black water-based ink, making it less messy to handle. In particular, the organic combination of the three resins results in excellent scratch-off performance and facilitates faster printing. Specifically, the styrene-acrylic emulsion copolymer provides good adhesion, scratch-off performance, and hardness to the scratch-off black ink layer; the water-based polyurethane resin, in addition to providing good scratch-off performance, also provides good flexibility to the ink layer; and the water-based acrylic resin has good resolubility, improving the ink's printability.

[0040] More preferably, the mass ratio of the waterborne polyurethane resin, styrene-acrylic resin, and waterborne acrylic resin is (5-7):(18-23):(10-15). Studies have found that waterborne resins within this ratio range can provide better performance for scratch-off black waterborne inks.

[0041] In some specific embodiments, the mass ratio of the waterborne polyurethane resin, styrene-acrylic resin and waterborne acrylic resin is 5:20:15, 7:23:15 or 7:18:10.

[0042] In some specific embodiments, the water-based resin content in the scratch-off black water-based ink is 35-50 wt%, preferably 35-45 wt%, more preferably 40 wt%; the pigment content is 35-50 wt%, preferably 35-43 wt%, more preferably 38 wt%. Within this range, better safety performance, scratch-off performance, and rollability can be obtained.

[0043] In some specific embodiments, the total content of the styrene-acrylic emulsion and the waterborne polyurethane resin in the scratch-off white waterborne ink is 20-45 wt%, preferably 30-43 wt%, and more preferably 38 wt%. Within this range, better safety performance, scratch-off performance, scratch resistance, and rollability can be obtained.

[0044] Specifically, the pigment is a black pigment, including one or more of carbon black, iron black, and aniline black. In some specific embodiments, the pigment is an aqueous black paste.

[0045] Specifically, the wetting agent may be a polyether siloxane copolymer. In some specific embodiments, the polyether siloxane copolymer may be selected from one or more of TEGO Wet 280, TEGO Wet 270, or BYK-333.

[0046] Specifically, the defoamer may be a polyether siloxane copolymer emulsion. In some specific embodiments, the polyether siloxane copolymer emulsion may be selected from one or more of TEGO 845, Tego Airex 902W, or TEGO Foamex 1488.

[0047] Preferably, the slip-refining agent is an aqueous silicone emulsion. In some specific embodiments, the aqueous silicone emulsion may be selected from one or both of DOWSIL 51 Additive or DOWSIL 8526 Additive.

[0048] Specifically, the titanium dioxide can be selected from rutile titanium dioxide.

[0049] Specifically, the dispersant may be a high molecular weight block copolymer. In some specific embodiments, the dispersant may be selected from one or both of the following: KS Rheorlow DS-361 dispersant (Korea) and TEGO Dispers 760W.

[0050] In some specific embodiments, the pigment is an aqueous black paste; the wetting agent is TEGO Wet 280; the defoamer is TEGO 845; the slip agent is DOWSIL 8526 Additive; the titanium dioxide is rutile titanium dioxide; and the dispersant is KS Rheorlow DS-361.

[0051] Specifically, the wetting agents, defoamers, and slipping agents in black water-based ink and white water-based ink can be the same or different.

[0052] The present invention also unexpectedly discovered that the combined use of water-based resin in scratch-off black water-based ink and water-based polyurethane resin (film-forming resin) in scratch-off white water-based ink balances the scratch-off performance of instant tickets and the scratch resistance of packaging. When instant tickets are placed in a high temperature and high humidity environment for 24 hours using an electric scratch-off instrument, the preferred formulation for aging scratch-off value is only 350g / 5B.

[0053] The instant-scratch flexographic water-based scratch-off ink of this invention includes scratch-off black water-based ink and scratch-off white water-based ink, which work synergistically in the scratch-off area of ​​the instant-scratch ticket. As the ink layer in direct contact with the release grease, the scratch-off black water-based ink's scratch-off performance is crucial to the overall scratch-off performance of the instant-scratch ticket. It not only protects the security of the printed information but also provides good adhesion and excellent spreading and wetting properties. Furthermore, through the combination of additives and water-based resin, it ensures good scratch-off performance and rollability. However, its scratch resistance is relatively weak. The scratch-off white water-based ink, on the other hand, has high opacity, providing ideal conditions for the spreading of four-color inks and spot color inks, improving the color saturation, leveling, and dot sharpness of the printed product. Through the organic combination of the film-forming resin and the scratch-off black water-based ink formulation, the scratch-off performance and scratch resistance of the scratch-off area are effectively balanced, resulting in an ink layer in the scratch-off area that not only has excellent scratch-off rollability and doesn't get hands dirty when handled, but also possesses excellent packaging scratch resistance.

[0054] The present invention also provides a method for preparing the above-mentioned flexographic water-based scratch-off ink, comprising:

[0055] 1) Prepare the scratch-off black water-based ink and the scratch-off white water-based ink respectively;

[0056] 2) Print two layers of scratch-off black water-based ink over the UV isolation oil, and then print two layers of scratch-off white water-based ink over the scratch-off black ink. This is the flexographic water-based scratch-off ink.

[0057] Typically, the amounts of the scratch-off black water-based ink and the surface scratch-off white water-based ink can be adjusted as needed. In some embodiments, to balance economic efficiency with the safety and scratch-off performance of the scratch-off area, 2-3 layers of scratch-off black and 2 layers of scratch-off white can be printed on the surface of the isolation oil using a 200 lpi anilox roller (ink load of 9.26 bcm).

[0058] Specifically, the method for preparing the scratch-off black water-based ink includes the following steps: firstly mixing water-based resin, pigment, defoamer, and deionized water, with a grinding and stirring speed of 1000-1500 r / min and a grinding and stirring time of 90-120 min, to obtain a mixed dispersion ①; secondly mixing the mixed dispersion ①, wetting agent, and slipping agent, with a stirring speed of 1000-1500 r / min and a stirring time of 30-40 min, to obtain the scratch-off black water-based ink.

[0059] Specifically, the method for preparing the scratch-off white water-based ink includes the following steps: firstly mixing deionized water, styrene-acrylic emulsion, titanium dioxide, dispersant, and defoamer, with a grinding and stirring speed of 1500-2000 r / min and a grinding and stirring time of 120-180 min, to obtain a mixed dispersion ②; secondly mixing the mixed dispersion ②, water-based polyurethane resin, wetting agent, and slipping agent, with a stirring speed of 1000-1500 r / min and a stirring time of 60-90 min, to obtain the scratch-off white water-based ink.

[0060] The present invention also includes the application of the flexographic water-based scratch-off ink in the preparation of printed instant lottery tickets or invoices requiring scratch-off prize redemption. For example, the instant lottery ticket is a welfare instant lottery ticket or a sports instant lottery ticket.

[0061] By printing two layers of the present invention's high-color-density scratch-off black water-based ink and two layers of the present invention's high-opacity scratch-off white water-based ink on a UV-blocking oil, the scratch-off black water-based ink and the scratch-off white water-based ink complement each other in terms of performance.

[0062] The instant invoice product has the following advantages through this invention:

[0063] Safety performance meets standards: ensuring the environmental friendliness and safety of instant lottery tickets; excellent scratch-off roll-up properties: improving the physical properties of the scratch-off ink layer for smoother scratching; hands-free operation: reducing ink residue generated when scratching, enhancing user experience; optimized performance balance: balancing scratch-off performance with packaging scratch resistance to meet diverse application needs.

[0064] Meanwhile, the scratch-off ink of this invention has excellent printability on instant ticket printing equipment and can support a high-speed printing speed of up to 300m / min, which is currently the highest printing speed for instant ticket products in China. Detailed Implementation

[0065] The present invention will be further described in detail below with reference to specific embodiments, but this is not intended to limit the scope of protection of the invention.

[0066] Scratching performance test of the scratch-off area:

[0067] (1) Scratch performance: Under indoor ambient temperature, with a load weight of 100g, the safety coating of the ticket sample can be scratched off in one go using a pencil scratch hardness tester.

[0068] (2) Aging test of scratch-off area: The invoice is placed in a constant temperature and humidity chamber at 80±5℃ and 80±5% or a drying oven at 95±5℃ for 24 hours. If the safety coating can be scratched off in one go using a pencil scratch hardness tester with a load weight of ≤500g / 5B, it is qualified.

[0069] Security:

[0070] (1) Use a fiber optic lamp to observe the density of the covering layer in the scratch-off area of ​​the instant ticket;

[0071] (2) The side light function of the document inspection instrument shows that there are no raised bumps in the shape of prize symbols in the scratch-off area of ​​the instant lottery ticket;

[0072] (3) The light-blocking properties of the scratch-off area of ​​the invoice were observed by the transmission point light source of the document inspection instrument, the light-blocking properties after the back was peeled off, and the light-blocking properties after the back was peeled off and wetted with reagent.

[0073] Ink printability: The printability of scratch-off black and scratch-off white water-based inks was tested on an instant ticket printing machine. At a printing speed of 300m / min, continuous printing for more than 12 hours showed good ink transfer and leveling properties, minimal bubbling, good resolubility, and no issues such as dirty printing plates or sticking to rollers. The ink printability was good.

[0074] Viscosity: The viscosity was tested according to GB / T 13217.4-2008, and the test conditions were Zahn2. # Fineness at 25℃: Fineness was tested using the method of GB / T 13217.3-2008.

[0075] pH: pH value was determined using the method specified in QB / T 2825-2006.

[0076] The following pigments are water-based black pastes, the wetting agent is TEGO Wet 280, the defoamer is TEGO 845, the slip agent is DOWSIL 8526 Additive, the titanium dioxide is rutile titanium dioxide, and the dispersant is KS Rheorlow DS-361 from South Korea, all of which are commercially available.

[0077] Example 1

[0078] This embodiment provides a flexographic water-based scratch-off ink, including scratch-off black water-based ink and scratch-off white water-based ink; wherein, the formulation of the scratch-off black water-based ink is as follows (parts by weight):

[0079] 40 parts of water-based resin;

[0080] 38 parts pigment;

[0081] 3 parts wetting agent;

[0082] 0.5 parts of defoamer;

[0083] 1 part of slippery additive;

[0084] 17.5 parts deionized water;

[0085] The waterborne resin is composed of waterborne polyurethane resin, styrene-acrylic resin and waterborne acrylic resin in a mass ratio of 5:20:15.

[0086] The formula for the scratch-off white water-based ink is as follows (parts by weight):

[0087] 40 parts titanium dioxide;

[0088] 13 parts of styrene-acrylic emulsion;

[0089] 25 parts of waterborne polyurethane resin;

[0090] 2.5 parts dispersant;

[0091] 3 parts wetting agent;

[0092] 1.5 parts defoamer;

[0093] 3 parts of slippery additive;

[0094] 12 portions of deionized water.

[0095] Preparation method of scratch-off black water-based ink: Water-based resin, pigment, defoamer and deionized water are mixed for the first time, and the grinding and stirring speed is 1000 r / min and the grinding and stirring time is 120 min to obtain mixed dispersion ①; The mixed dispersion ①, wetting agent and slipping agent are mixed for the second time, and the stirring speed is 1500 r / min and the stirring time is 40 min to obtain scratch-off black water-based ink.

[0096] Preparation method of scratch-off white water-based ink: Deionized water, styrene-acrylic emulsion, titanium dioxide, dispersant and defoamer are mixed for the first time, and the grinding and stirring speed is 2000 r / min for 120 min to obtain mixed dispersion ②; Mixed dispersion ②, water-based polyurethane resin, wetting agent and slipping agent are mixed for the second time, and the stirring speed is 1000 r / min for 90 min to obtain the scratch-off white water-based ink.

[0097] Two layers of scratch-off black water-based ink are overprinted on the UV isolation oil, and then two layers of scratch-off white water-based ink are overprinted on the scratch-off black ink. This is the flexographic water-based scratch-off ink of this embodiment.

[0098] Example 2

[0099] This embodiment provides a flexographic water-based scratch-off ink, including scratch-off black water-based ink and scratch-off white water-based ink; wherein, the formulation of the scratch-off black water-based ink is as follows (parts by weight):

[0100] 45 parts of water-based resin;

[0101] 35 parts pigment;

[0102] 2.5 parts wetting agent;

[0103] 1.5 parts defoamer;

[0104] 1 part of slippery additive;

[0105] 15 parts deionized water;

[0106] The waterborne resin is composed of waterborne polyurethane resin, styrene-acrylic emulsion and waterborne acrylic resin in a mass ratio of 7:23:15.

[0107] The formula for the scratch-off white water-based ink is as follows (parts by weight):

[0108] 35 parts titanium dioxide;

[0109] 15 parts of styrene-acrylic emulsion;

[0110] 28 parts of waterborne polyurethane resin;

[0111] 3 parts dispersant;

[0112] 3 parts wetting agent;

[0113] 1.5 parts defoamer;

[0114] 3 parts of slippery additive;

[0115] 11.5 parts deionized water.

[0116] The preparation methods for scratch-off black water-based ink and scratch-off white water-based ink are the same as in Example 1.

[0117] Two layers of scratch-off black water-based ink are overprinted on the UV isolation oil, and then two layers of scratch-off white water-based ink are overprinted on the scratch-off black ink. This is the flexographic water-based scratch-off ink of this embodiment.

[0118] Example 3

[0119] This embodiment provides a flexographic water-based scratch-off ink, including scratch-off black water-based ink and scratch-off white water-based ink; wherein, the formulation of the scratch-off black water-based ink is as follows (parts by weight):

[0120] 35 parts of water-based resin;

[0121] 43 parts pigment;

[0122] 2.5 parts wetting agent;

[0123] 0.5 parts of defoamer;

[0124] 1.2 parts of slippery additive;

[0125] 17.8 parts of deionized water;

[0126] The waterborne resin is composed of waterborne polyurethane resin, styrene-acrylic emulsion and waterborne acrylic resin in a mass ratio of 7:18:10.

[0127] The formula for the scratch-off white water-based ink is as follows (parts by weight):

[0128] 45 parts titanium dioxide;

[0129] 10 parts of styrene-acrylic emulsion;

[0130] 20 parts of waterborne polyurethane resin;

[0131] 2.5 parts dispersant;

[0132] 2.5 parts wetting agent;

[0133] 1.5 parts defoamer;

[0134] 4 parts of slippery additive;

[0135] 14.5 parts deionized water.

[0136] The preparation methods for scratch-off black water-based ink and scratch-off white water-based ink are the same as in Example 1.

[0137] Two layers of scratch-off black water-based ink are overprinted on the UV isolation oil, and then two layers of scratch-off white water-based ink are overprinted on the scratch-off black ink. This is the flexographic water-based scratch-off ink of this embodiment.

[0138] Example 4

[0139] This embodiment provides a flexographic water-based scratch-off ink, including scratch-off black water-based ink and scratch-off white water-based ink; wherein, the formulation of the scratch-off black water-based ink is as follows (parts by weight):

[0140] 50 parts of water-based resin;

[0141] 35 parts pigment;

[0142] 2.5 parts wetting agent;

[0143] 1.5 parts defoamer;

[0144] 1 part of slippery additive;

[0145] 10 parts deionized water;

[0146] The waterborne resin is composed of waterborne polyurethane resin, styrene-acrylic emulsion and waterborne acrylic resin in a mass ratio of 7:23:15.

[0147] The formula for the scratch-off white water-based ink is as follows (parts by weight):

[0148] 35 parts titanium dioxide;

[0149] 15 parts of styrene-acrylic emulsion;

[0150] 30 parts of waterborne polyurethane resin;

[0151] 3 parts dispersant;

[0152] 3 parts wetting agent;

[0153] 1.5 parts defoamer;

[0154] 2 parts of slippery additive;

[0155] 10.5 parts deionized water.

[0156] The preparation methods for scratch-off black water-based ink and scratch-off white water-based ink are the same as in Example 1.

[0157] Two layers of scratch-off black water-based ink are overprinted on the UV isolation oil, and then two layers of scratch-off white water-based ink are overprinted on the scratch-off black ink. This is the flexographic water-based scratch-off ink of this embodiment.

[0158] Comparative Example 1

[0159] The flexographic water-based scratch-off ink includes scratch-off black water-based ink and scratch-off white water-based ink; the only difference from Example 1 is that the water-based resin of the scratch-off black water-based ink is composed of water-based polyurethane resin and water-based acrylic resin in a mass ratio of 25:15.

[0160] Comparative Example 2

[0161] The flexographic water-based scratch-off ink includes scratch-off black water-based ink and scratch-off white water-based ink; the only difference from Example 1 is that the water-based polyurethane resin of the scratch-off white water-based ink is replaced with an equal amount of water-based acrylic resin.

[0162] Experiment 1

[0163] The test results of the flexographic water-based scratch-off ink in Example 1 are shown in Table 1. Among them, scratch-off black and scratch-off white are the scratch-off black water-based ink and scratch-off white water-based ink of Example 1, respectively; scratch-off black + scratch-off white is the flexographic water-based scratch-off ink of Example 1.

[0164] Table 1 Test Results of Flexographic Water-Based Scratch-Off Ink

[0165]

[0166] As shown in Table 1, the scratch-off black ink has poor scratch resistance and slightly poor rollability after film formation, which will affect the subsequent packaging of instant tickets. The scratch-off white ink has excellent scratch resistance and rollability, but its safety performance and scratch-off performance are poor, especially when placed in a high temperature and high humidity environment (80±5℃, 80±5% / 24h). A pencil hardness test shows its scratch-off value is greater than 700g, which does not meet quality requirements. When scratch-off black and scratch-off white are used together, the instant ticket exhibits excellent performance in terms of safety, scratch-off performance, scratch resistance, and rollability.

[0167] The test results of flexographic water-based scratch-off inks in Examples 1-4 and Comparative Examples 1-2 are shown in Table 2.

[0168] Table 2 Test Results of Flexographic Water-Based Scratch-Off Ink

[0169]

[0170] Table 2 shows that Examples 1-4 all meet the quality requirements in terms of safety performance, scratch-off performance, scratch resistance, and rollability of the scratch-off area. Examples 2 and 4 have a higher proportion of resin and a relatively lower proportion of pigment in their scratch-off black and white water-based inks, resulting in slightly lower safety performance compared to Example 1. Under high temperature and humidity conditions (80±5℃, 80±5% / 24h), the scratch-off value of the instant ticket is higher, increasing from 350g to 450g. In Example 3, a higher proportion of pigment and a relatively lower proportion of resin resulted in better scratch-off performance, but the rollability of the ink layer was slightly worse than in Example 1. Example 1 has the best overall performance, and Examples 2-4 also meet the quality requirements.

[0171] Although Comparative Examples 1 and 2 exhibit good ink fineness, viscosity, pH, and printability, the aging and scratch-off performance of the scratch-off area in Comparative Example 1, by omitting the styrene-acrylic emulsion in the water-based resin of the scratch-off black ink (correspondingly increasing the amount of water-based polyurethane resin), is poor. Similarly, in Comparative Example 2, by replacing the water-based polyurethane resin with water-based acrylic resin in the scratch-off white ink, the scratch resistance and roll-forming performance of the scratch-off area are poor. Due to the poor roll-forming performance, the ink layer is easily crushed, resulting in dirty hands covered in ink powder. Therefore, this invention utilizes a combination of water-based resin in the scratch-off black ink and water-based polyurethane resin in the scratch-off white ink to solve both the problems of poor aging and scratch resistance, poor roll-forming performance, and easy hand soiling in the scratch-off area of ​​the instant ticket.

[0172] The experimental results above show that the flexographic water-based scratch-off ink of the present invention has the following beneficial effects:

[0173] 1. A combination of two layers of high-concentration scratch-off black water-based ink and two layers of high-opacity scratch-off white ink is printed on top of the UV isolation oil, making the data information on the instant ticket unreadable under strong light, thus ensuring the security of the instant ticket.

[0174] 2. The high-coverage scratch-off water-based ink for instant lottery tickets has excellent coverage, ensuring good visual appeal on the front of the ticket.

[0175] 3. The combined use of water-based resin in the scratch-off black water-based ink and film-forming resin in the scratch-off white water-based ink balances the scratch-off performance of the instant ticket and the scratch resistance of the packaging. The scratch-off value of the instant ticket, tested with an electric scratch-off tester, is 350-450g / 5B. This provides excellent scratch-off performance for the coating in the scratch-off area, allowing the ink layer in the scratch-off area of ​​the instant ticket to be easily scratched off.

[0176] 4. The instant ticket flexographic water-based scratch-off ink can achieve high-speed printing of instant tickets at a speed of 300m / min, and the ink has excellent printability.

[0177] 5. The ink layer in the scratch-off area is easy to scratch off, has good rollability, and does not get your hands dirty when you handle it. The scratching process is smooth and stress-relieving, greatly improving the scratching experience for lottery buyers.

[0178] 6. The ink layer in the scratch-off area has good rollability, forming a rolled strip shape, which prevents solid ink powder from flying around, ensuring the cleanliness of the sales area and avoiding affecting the health of lottery buyers.

[0179] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A flexographic water-based scratch-off ink, characterized in that, This includes scratch-off black water-based ink and scratch-off white water-based ink; wherein, the scratch-off black water-based ink, by weight, comprises the following components: 35-50 parts of water-based resin; 35-50 parts pigment; 2-4 parts wetting agent; Defoamer 0.5-3 parts; 0.5-1.5 parts of slippery additive; 10-30 parts deionized water; The waterborne resin is composed of waterborne polyurethane resin, styrene-acrylic resin and waterborne acrylic resin in a mass ratio of (5-15):(15-30):(10-20); The scratch-off water-based ink, by weight, comprises the following components: 35-50 parts titanium dioxide; 5-15 parts of styrene-acrylic emulsion; 15-30 parts of waterborne polyurethane resin; Dispersant 0.5-3.5 parts; 2-4 parts wetting agent; Defoamer 0.5-3 parts; 2-5 parts of slippery additive; 10-20 parts deionized water.

2. The flexographic water-based scratch-off ink according to claim 1, characterized in that, The scratch-off black water-based ink comprises the following components by weight: 35-45 parts of water-based resin; 35-43 parts pigment; 2.5-3 parts wetting agent; 0.5-1.5 parts of defoamer; 1-1.2 parts of slippery additive; 15-17.8 parts deionized water; And / or, the scratch-off water-based ink comprises the following components by weight: 35-45 parts titanium dioxide; 10-15 parts of styrene-acrylic emulsion; 20-28 parts of waterborne polyurethane resin; Dispersant 2.5-3 parts; 2.5-3 parts wetting agent; 1.5-3 parts defoamer; 3-4 parts of slippery additive; 10.5-14.5 parts deionized water.

3. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, In the scratch-off black water-based ink, the content of the water-based resin is 35-50 wt%; the content of the pigment is 35-50 wt%; and / or, In the scratch-off white water-based ink, the sum of the contents of the styrene-acrylic emulsion and the water-based polyurethane resin is 20-45 wt% of the water-based resin content.

4. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, In the scratch-off black water-based ink, the content of the water-based resin is 35-45 wt%; the content of the pigment is 35-43 wt%; and / or, In the scratch-off white water-based ink, the sum of the contents of the styrene-acrylic emulsion and the water-based polyurethane resin is 30-43 wt% of the water-based resin.

5. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, In the scratch-off black water-based ink, the content of the water-based resin is 40 wt%; the content of the pigment is 38 wt%; and / or, In the scratch-off white water-based ink, the sum of the contents of the styrene-acrylic emulsion and the water-based polyurethane resin is 38 wt% of the water-based resin.

6. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, The mass ratio of the waterborne polyurethane resin, styrene-acrylic resin and waterborne acrylic resin is (5-7):(18-23):(10-15).

7. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, The pigment is a black pigment; and / or, The wetting agent is a polyether siloxane copolymer; and / or... The defoamer is a polyether silicone copolymer emulsion; and / or... The slip-refining agent is an aqueous silicone emulsion; and / or... The titanium dioxide is rutile titanium dioxide; and / or... The dispersant is a high molecular weight block copolymer.

8. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, The pigment is selected from one or more of carbon black, iron black, and aniline black; and / or, The wetting agent is selected from one or more of TEGO Wet 280, TEGO Wet 270, or BYK-333; and / or, The defoamer is selected from one or more of TEGO 845, Tego Airex 902W, or TEGO Foamex 1488; and / or, The slip-enhancing agent is selected from one or both of DOWSIL 51 Additive or DOWSIL 8526 Additive; and / or, The dispersant is selected from one or both of the following: KS Rheorlow DS-361 dispersant from South Korea and TEGO Dispers 760W.

9. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, The pigment is a water-based black paste.

10. The flexographic water-based scratch-off ink according to claim 1 or 2, characterized in that, The pigment is an aqueous black paste; the wetting agent is TEGO Wet 280; the defoamer is TEGO 845; the slip agent is DOWSIL8526 Additive; the titanium dioxide is rutile titanium dioxide; and the dispersant is KS Rheorlow DS-361.

11. The method for preparing the flexographic water-based scratch-off ink according to any one of claims 1-10, characterized in that, include: 1) Prepare the scratch-off black water-based ink and the scratch-off white water-based ink respectively; 2) Print two layers of scratch-off black water-based ink over the UV isolation oil, and then print two layers of scratch-off white water-based ink over the scratch-off black ink. This is the flexographic water-based scratch-off ink.

12. The method for preparing flexographic water-based scratch-off ink according to claim 11, characterized in that, The preparation method of the scratch-off black water-based ink includes the following steps: A water-based resin, pigment, defoamer, and deionized water are first mixed, with a grinding and stirring speed of 1000-1500 r / min and a grinding and stirring time of 90-120 min, to obtain a mixed dispersion ①; The mixed dispersion ①, wetting agent, and slipping agent are second mixed, with a stirring speed of 1000-1500 r / min and a stirring time of 30-40 min, to obtain the scratch-off black water-based ink; The preparation method of the scratch-off white water-based ink includes the following steps: firstly, deionized water, styrene-acrylic emulsion, titanium dioxide, dispersant, and defoamer are mixed, and the grinding and stirring speed is 1500-2000 r / min for 120-180 min to obtain a mixed dispersion ②; secondly, the mixed dispersion ②, water-based polyurethane resin, wetting agent, and slipping agent are mixed, and the stirring speed is 1000-1500 r / min for 60-90 min to obtain the scratch-off white water-based ink.

13. The use of the flexographic water-based scratch-off ink according to any one of claims 1-10 in the preparation of printed instant invoices or invoices that require scratch-off for prize redemption.

14. The application according to claim 13, characterized in that, The instant tickets mentioned are welfare instant tickets or sports instant tickets.

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