Flexible water-based scraping ink as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of printing, and particularly relates to flexographic water-based scraping ink as well as a preparation method and application thereof. The flexographic water-based scraping ink comprises scraping black water-based ink and scraping white water-based ink; the scratch-off black water-based ink comprises 35-50 parts of water-based resin; 35 to 50 parts of pigment; 2-4 parts of a wetting agent; 0.5 to 3 parts of a defoaming agent; 0.5 to 1.5 parts of a smooth auxiliary agent; 10 to 30 parts of deionized water; the scraping white water-based ink comprises the following components: 35-50 parts of titanium dioxide; 5 to 15 parts of styrene-acrylic emulsion; 15 to 30 parts of waterborne polyurethane resin; 0.5 to 3.5 parts of a dispersant; 2-4 parts of a wetting agent; 0.5 to 3 parts of a defoaming agent; 2-5 parts of a smooth auxiliary agent; and 10 to 20 parts of deionized water. According to the invention, the problems that an instant billing ticket product is poor in roll forming performance after being scraped and ink residues are easily generated and hands are dirty when a lottery buyer scrapes the product are solved, and a more ideal solution is provided for the instant billing ticket product.

Description

Technical Field

[0001] The present invention belongs to the field of printing technology, and particularly relates to a flexographic water-based scratch-off ink, a preparation method thereof, and an application thereof. Background Art

[0002] The scratch-off area ink system of instant tickets usually includes, from bottom to top in sequence: primer ink, interference pattern, inkjet ink, UV isolation oil, scratch-off ink, and four-color or spot color ink. The scratch-off black ink layer, scratch-off white ink layer, and surface color image printed on the UV isolation oil are collectively referred to as the scratch-off layer. The scratch-off layer is one of the core technologies of instant ticket printing, and the key lies in the performance of the two functional inks of scratch-off black and scratch-off white. The main functions of these two inks are to cover the data information at the bottom of the UV isolation oil to ensure the security of instant ticket information, and at the same time have good scratch-off performance and certain anti-scratch performance. In addition, the scratch-off ink also needs to have good film-forming properties, so that the scratched ink layer has rollability, avoiding ink layer residues from dirtying hands and improving the user experience.

[0003] The scratch-off black ink and the scratch-off white ink each have different performance requirements. In addition to high hiding power and good film-forming properties, the scratch-off black ink also needs to have excellent compatibility with the UV isolation oil, including good leveling property and strong adhesion on the isolation oil. The scratch-off white ink needs to have strong anti-scratch and anti-blocking properties to improve the service durability and product quality of instant tickets.

[0004] In the prior art, several patents have studied and improved the scratch-off ink. For example: Chinese Patent CN110791144A discloses a water-based scratch-off gray ink for screen printing and a preparation method thereof; Chinese Patent CN104774500A discloses a water-based flexographic scratch-off white ink, a preparation method thereof, and an application thereof; Chinese Patent CN106867307A discloses a preparation method of a water-based black scratch-off ink. However, the scratch-off inks in these patents still have deficiencies in actual applications. For example, the rollability of the scratched ink layer is poor, resulting in easy soiling of hands by ink residues and affecting the user's scratch-off experience. In addition, the performance of these inks is not good under high-speed printing conditions, which is not conducive to improving the production efficiency of enterprises. Therefore, developing scratch-off inks with more excellent performance has become an urgent need in the field of instant ticket printing. Summary of the Invention

[0005] To solve at least one of the problems in the prior art, the present invention provides a flexographic water-based scratch-off ink, a preparation method thereof, and an application thereof. Through the optimization and collaborative design of the formulations of the scratch-off black water-based ink and the scratch-off white water-based ink in the instant ticket scratch-off system, the present invention forms complementary advantages in performance. Aiming at the problems of poor rollability of the scratched instant ticket products, easy generation of ink residues and dirty hands when lottery buyers scratch, the scratch-off ink technology of the present invention significantly improves the above deficiencies and provides a more ideal solution for instant ticket products.

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

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

[0008] Pigment 35-50 parts;

[0009] Wetting agent 2-4 parts;

[0010] Defoaming agent 0.5-3 parts;

[0011] 0.5-1.5 parts of slip aid;

[0012] 10-30 parts of deionized water;

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

[0014] The scraped white water-based ink comprises the following components in parts by weight:

[0015] 35-50 parts of titanium dioxide;

[0016] Styrene acrylic emulsion 5-15 parts;

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

[0018] Dispersant 0.5-3.5 parts;

[0019] Wetting agent 2-4 parts;

[0020] Defoaming agent 0.5-3 parts;

[0021] 2-5 parts of slip agent;

[0022] 10-20 parts of deionized water.

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

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

[0025] Pigment 35-43 parts;

[0026] Wetting agent 2.5-3 parts;

[0027] Defoaming agent 0.5-1.5 parts;

[0028] 1-1.2 parts of slip aid;

[0029] 15-17.8 parts of deionized water.

[0030] Preferably, the scraped white water-based ink comprises the following components in parts by weight:

[0031] 35-45 parts of titanium dioxide;

[0032] Styrene acrylic emulsion 10-15 parts;

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

[0034] Dispersant 2.5-3 parts;

[0035] Wetting agent 2.5-3 parts;

[0036] 1.5-3 parts of defoaming agent;

[0037] 3-4 parts of slip agent;

[0038] 10.5-14.5 parts of deionized water.

[0039] The inventors have found that the use of an aqueous resin composed of an aqueous polyurethane resin, a styrene-acrylic resin and an aqueous acrylic resin can significantly improve the rollability of the scrape-off black water-based ink, and the hand does not get dirty when twisting it. In particular, the organic combination of the three resins makes the scrape-off black ink have excellent scraping performance and is conducive to increasing the printing speed. Among them, the styrene-acrylic emulsion copolymer emulsion provides good fastness, scraping performance and hardness for the scrape-off black ink layer, the aqueous polyurethane resin provides good flexibility for the ink layer in addition to providing good scraping performance, and the aqueous acrylic resin has good solubility, which improves the printing suitability of the ink.

[0040] More preferably, the mass ratio of the water-based polyurethane resin, styrene acrylic resin and water-based acrylic resin is (5-7): (18-23): (10-15). Studies have found that water-based resins within this ratio range can make the black water-based ink have better performance.

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

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

[0043] In some specific embodiments, in the scraping white water-based ink, the sum of the contents of the styrene-acrylic emulsion and the waterborne polyurethane resin is 20-45 wt% of the content of the water-based resin, preferably 30-43 wt%, and more preferably 38 wt%. Better safety performance, scraping performance, scratch resistance, and rollability can be obtained within this range.

[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 a water-based black paste.

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

[0046] Specifically, the defoaming agent can be a polyether silicone copolymer emulsion. In some specific embodiments, the polyether silicone copolymer emulsion can be selected from one or several of TEGO845, Tego Airex 902W, or TEGO Foamex1488.

[0047] Preferably, the slip aid is a water-based silicone emulsion. In some specific embodiments, the water-based silicone emulsion can be selected from one or two of DOWSIL 51Additive or DOWSIL 8526Additive.

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

[0049] Specifically, the dispersant can be a high molecular weight block copolymer. In some specific embodiments, the dispersant can be selected from one or two of the Korean KS Rheorlow DS-361 dispersant and TEGO Dispers 760W.

[0050] In some specific embodiments, the pigment is a water-based black paste; the wetting agent is TEGO Wet 280; the defoaming agent is TEGO845; the slip aid is DOWSIL 8526Additive; the titanium dioxide is rutile titanium dioxide; the dispersant is KS Rheorlow DS-361.

[0051] Specifically, the wetting agent, defoaming agent, and slip aid in the scraping black water-based ink and the scraping white water-based ink can be the same or different.

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

[0053] The flexographic water-based scratching ink of the instant scratch ticket of the present invention includes the black water-based ink for scratching and the white water-based ink for scratching, and the two play a synergistic role in the scratching area of the instant scratch ticket. As the ink layer directly contacting the isolation oil, the scratching performance of the black water-based ink for scratching is crucial for the overall scratching property of the instant scratch ticket. It can not only protect the security of the inkjet information but also provide good adhesion and excellent spreading and wetting properties. At the same time, through the cooperation of additives and the aqueous resin, good scratching performance and rollability are ensured. However, its anti-scratch performance is relatively weak. The white water-based ink for scratching has high covering power, providing ideal conditions for the spreading of four-color inks and spot colors, and improving the color saturation, leveling property, and dot sharpness of the printed product. Through the organic combination of the film-forming resin and the formulation of the black water-based ink for scratching, the scratching performance and anti-scratch performance in the scratching area are effectively balanced, making the ink layer in the scratching area not only have good scratching and rollability and not dirty hands when twisted by hand but also have excellent anti-scratch performance for packaging.

[0054] The present invention also provides a preparation method for the above-mentioned flexographic water-based scratching ink, including:

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

[0056] 2) Overprint two layers of the black water-based ink for scratching on the UV isolation oil, and then overprint two layers of the white water-based ink for scratching on the black ink for scratching, which is the flexographic water-based scratching ink.

[0057] Generally, the dosages of the black water-based ink for scratching and the top-layer white water-based ink for scratching can be appropriately adjusted according to needs. In some embodiments, in order to balance economic benefits, safety performance, and scratching performance in the scratching area, a 200 lpi anilox roller (ink loading capacity is 9.26 bcm) can be used to print 2 - 3 layers of black for scratching and 2 layers of white for scratching on the surface of the isolation oil.

[0058] Specifically, the preparation method of the black water-based ink for scratching includes the following steps: First, mix the aqueous resin, pigment, defoamer, and deionized water, with the grinding and stirring speed of 1000 - 1500 r / min and the grinding and stirring time of 90 - 120 min to obtain the mixed dispersion liquid ①; then mix the mixed dispersion liquid ①, wetting agent, and slip aid, with the stirring speed of 1000 - 1500 r / min and the stirring time of 30 - 40 min to obtain the black water-based ink for scratching.

[0059] Specifically, the preparation method of the scraping white water-based ink includes the following steps: deionized water, styrene-acrylic emulsion, titanium dioxide, dispersant and defoamer are subjected to a first mixing, the grinding and stirring speed is 1500-2000 r / min, and the grinding and stirring time is 120-180 min to obtain a mixed dispersion liquid ②; the mixed dispersion liquid ②, waterborne polyurethane resin, wetting agent and slip aid are subjected to a second mixing, the stirring speed is 1000-1500 r / min, and the stirring time is 60-90 min to obtain the scraping white water-based ink.

[0060] The present invention also includes the application of the flexographic water-based scraping ink in the preparation of printed instant lottery tickets or invoices that need to be scratched for prize redemption. For example, the instant lottery ticket is a welfare instant lottery ticket or a sports instant lottery ticket.

[0061] By printing a combination of two layers of the scraping black water-based ink with high color concentration and two layers of the scraping white water-based ink with high hiding power of the present invention on the UV isolation oil, the scraping black water-based ink and the scraping white water-based ink form complementary advantages in performance.

[0062] Through the present invention, the instant lottery ticket product has the following advantages:

[0063] The safety performance meets the standard: ensuring the environmental protection and use safety of the instant lottery ticket; excellent scraping rollability: improving the physical properties of the scraping ink layer to make the scraping smoother; no dirty hands when twisted by hand: reducing the generation of ink residues when the lottery purchaser scratches, improving the user experience; performance balance optimization: taking into account both the scraping performance and the anti-scratch performance of the packaging, meeting the application requirements in multiple aspects.

[0064] At the same time, the scraping ink of the present invention has excellent printing suitability on the instant lottery ticket printing equipment, and can support a high-speed printing speed of up to 300 m / min, which is the highest printing speed of domestic instant lottery ticket products at present. Specific Embodiments

[0065] The following further elaborates on the present invention in detail with reference to specific embodiments, but does not limit the protection scope of the invention thereby.

[0066] Scraping performance test of the scraping area:

[0067] (1) Scraping performance: At room temperature, with a load weight of 100 g of the weight, the safety coating of the ticket sample can be scraped off at one time using a pencil scratch hardness tester.

[0068] (2) Aging test of the scraping area: The instant lottery ticket is placed in a constant temperature and humidity chamber at a temperature of 80 ± 5 °C and a humidity of 80 ± 5% or in a drying oven at 95 ± 5 °C for 24 h. Using a pencil scratch hardness tester with a load weight of ≤ 500 g / 5B, the safety coating can be scraped off at one time, which is considered qualified.

[0069] Safety:

[0070] (1) Observe the compactness of the covering layer in the scratch area of the instant scratch lottery ticket using an optical fiber lamp;

[0071] (2) Observe that there are no raised shapes of winning symbols in the scratch area of the instant scratch lottery ticket using the side light function of a document inspection instrument;

[0072] (3) Observe the light-blocking property of the scratch area of the instant scratch lottery ticket using the transmitted point light source of a document inspection instrument, the light-blocking property after back peeling, and the light-blocking property after back peeling and soaking with a reagent.

[0073] Ink printing suitability: Test the printing suitability of the water-based inks for scratch-off black and scratch-off white on the instant scratch lottery ticket printing machine. When the printing speed is 300 m / min, continuously print for more than 12 h. The ink transferability and leveling performance are good, the foaming is not serious, the re-solubility is good, and there are no problems such as dirty plates and sticking rollers. The ink printing suitability is good.

[0074] Viscosity: Detect the viscosity using the method of GB / T 13217.4-2008, and the detection condition is Zahn2 # cup, 25 °C Fineness: Detect the fineness using the method of GB / T 13217.3-2008.

[0075] pH: Detect the pH value using the method of QB / T 2825-2006.

[0076] The following pigments are water-based black pastes, the wetting agent is TEGO Wet 280, the defoaming agent is TEGO845, the slip aid is DOWSIL 8526 Additive, the titanium dioxide is rutile titanium dioxide, and the dispersant is Korean KS Rheorlow DS-361, all of which are commercially available.

[0077] Example 1

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

[0079] 40 parts of water-based resin;

[0080] 38 parts of pigment;

[0081] 3 parts of wetting agent;

[0082] 0.5 part of defoaming agent;

[0083] 1 part of slip aid;

[0084] 17.5 parts of deionized water;

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

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

[0087] 40 parts of titanium dioxide;

[0088] 13 parts of styrene-acrylic emulsion;

[0089] 25 parts of waterborne polyurethane resin;

[0090] 2.5 parts of dispersant;

[0091] 3 parts of wetting agent;

[0092] 1.5 parts of defoamer;

[0093] 3 parts of slip aid;

[0094] 12 parts of deionized water.

[0095] Preparation method of scraping black water-based ink: First mix the waterborne resin, pigment, defoamer and deionized water, with the grinding and stirring speed of 1000 r / min and the grinding and stirring time of 120 min to obtain the mixed dispersion liquid ①; then mix the mixed dispersion liquid ①, wetting agent and slip aid, with the stirring speed of 1500 r / min and the stirring time of 40 min to obtain the scraping black water-based ink.

[0096] Preparation method of scraping white water-based ink: First mix the deionized water, styrene-acrylic emulsion, titanium dioxide, dispersant and defoamer, with the grinding and stirring speed of 2000 r / min and the grinding and stirring time of 120 min to obtain the mixed dispersion liquid ②; then mix the mixed dispersion liquid ②, waterborne polyurethane resin, wetting agent and slip aid, with the stirring speed of 1000 r / min and the stirring time of 90 min to obtain the scraping white water-based ink.

[0097] Overprint two layers of scraping black water-based ink on the UV isolation oil, and then overprint two layers of scraping white water-based ink on the scraping black ink, which is the flexographic water-based scraping ink of this embodiment.

[0098] Example 2

[0099] This embodiment provides a flexographic water-based scraping ink, including scraping black water-based ink and scraping white water-based ink; among them, the formula of the scraping black water-based ink is as follows (parts by weight):

[0100] 45 parts of waterborne resin;

[0101] 35 parts of pigment;

[0102] 2.5 parts of wetting agent;

[0103] 1.5 parts of defoamer;

[0104] 1 part of smoothness aid;

[0105] 15 parts of deionized water;

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

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

[0108] 35 parts of titanium dioxide;

[0109] 15 parts of styrene-acrylic emulsion;

[0110] 28 parts of aqueous polyurethane resin;

[0111] 3 parts of dispersant;

[0112] 3 parts of wetting agent;

[0113] 1.5 parts of defoamer;

[0114] 3 parts of smoothness aid;

[0115] 11.5 parts of deionized water.

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

[0117] Overprint two layers of scratch-off black water-based ink on the UV isolation oil, and then overprint two layers of scratch-off white water-based ink on the scratch-off black ink, which is the flexographic water-based scratch-off ink of this example.

[0118] Example 3

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

[0120] 35 parts of aqueous resin;

[0121] 43 parts of pigment;

[0122] 2.5 parts of wetting agent;

[0123] 0.5 part of defoamer;

[0124] 1.2 parts of smoothness aid;

[0125] 17.8 parts of deionized water;

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

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

[0128] 45 parts of titanium dioxide;

[0129] 10 parts of styrene-acrylic emulsion;

[0130] 20 parts of waterborne polyurethane resin;

[0131] 2.5 parts of dispersant;

[0132] 2.5 parts of wetting agent;

[0133] 1.5 parts of defoamer;

[0134] 4 parts of slip aid;

[0135] 14.5 parts of deionized water.

[0136] The preparation methods of the scratched black water-based ink and the scratched white water-based ink are the same as those in Example 1.

[0137] Overprint two layers of the scratched black water-based ink on the UV isolation oil, and then overprint two layers of the scratched white water-based ink on the scratched black ink, which is the flexographic water-based scratched ink of this example.

[0138] Example 4

[0139] This example provides a flexographic water-based scratched ink, including a scratched black water-based ink and a scratched white water-based ink; among them, the formula of the scratched black water-based ink is as follows (parts by weight):

[0140] 50 parts of water-based resin;

[0141] 35 parts of pigment;

[0142] 2.5 parts of wetting agent;

[0143] 1.5 parts of defoamer;

[0144] 1 part of slip aid;

[0145] 10 parts of deionized water;

[0146] The water-based resin is composed of waterborne polyurethane resin, styrene-acrylic emulsion and water-based acrylic resin according to the mass ratio of 7:23:15.

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

[0148] 35 parts of titanium dioxide;

[0149] 15 parts of styrene-acrylic emulsion;

[0150] 30 parts of waterborne polyurethane resin;

[0151] 3 parts of dispersant;

[0152] 3 parts of wetting agent;

[0153] Defoamer: 1.5 parts;

[0154] Smoothing agent: 2 parts;

[0155] Deionized water: 10.5 parts.

[0156] The preparation methods of the scratched black water-based ink and the scratched white water-based ink are the same as those in Example 1.

[0157] Overprint two layers of scratched black water-based ink on the UV isolation oil, and then overprint two layers of scratched white water-based ink on the scratched black ink, which is the flexographic water-based scratched ink of this example.

[0158] Comparative Example 1

[0159] Flexographic water-based scratched ink, including scratched black water-based ink and scratched white water-based ink; the difference from Example 1 is only that: the water-based resin of the scratched 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] Flexographic water-based scratched ink, including scratched black water-based ink and scratched white water-based ink; the difference from Example 1 is only that: the water-based polyurethane resin of the scratched 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 scratched ink of Example 1 are shown in Table 1. Among them, scratched black and scratched white are the scratched black water-based ink and the scratched white water-based ink of Example 1 respectively; scratched black + scratched white is the flexographic water-based scratched ink of Example 1.

[0164] Table 1 Test results of flexographic water-based scratched ink

[0165]

[0166] As can be seen from Table 1, the anti-scratch performance and the winding property of the scratched black ink after film formation are poor, which will affect the packaging of the subsequent instant lottery tickets. The anti-scratch and winding properties of the scratched white are very good, but the safety performance and the scratching performance are not good. Especially when placed in a high temperature and high humidity environment (80±5°C, 80±5% / 24h), the scratch value tested by a pencil hardness tester is greater than 700g, which does not meet the quality requirements. When the scratched black and the scratched white are used in combination, the safety performance, the scratching performance, the anti-scratch and the winding property of the scratched area of the instant lottery ticket have excellent performance in all aspects.

[0167] The test results of the flexographic water-based scratched ink of Examples 1-4 and Comparative Examples 1-2 are shown in Table 2.

[0168] Table 2 Test results of flexographic water-based scratched ink

[0169]

[0170] As can be seen from Table 2, in Examples 1-4, the safety performance, scraping performance, scratch resistance, and rollability of the immediate lottery ticket scraping area all meet the quality requirements. Among them, in Examples 2 and 4, the proportion of resin in the black water-based ink and the white water-based ink for scraping is relatively large, and the proportion of pigment is relatively small, so the safety performance is slightly worse than that of Example 1. Under high temperature and high humidity conditions (80±5°C, 80±5% / 24h), the scraping value of the immediate lottery ticket is on the high side, increasing from 350 g to 450 g. In Example 3, when the proportion of color paste is relatively large and the proportion of resin is relatively small, the scraping performance of the ink layer is better, but the rollability of the ink layer is also slightly worse than that of Example 1. The comprehensive performance of Example 1 is the best, and Examples 2-4 also meet the quality requirements.

[0171] Although the fineness, viscosity, pH, and printing suitability of the inks in Comparative Example 1 and Comparative Example 2 are good, after omitting the styrene-acrylic emulsion from the water-based resin in the black water-based ink for scraping in Comparative Example 1 (correspondingly increasing the amount of water-based polyurethane resin), the aging scraping performance of the scraping area of the immediate lottery ticket is poor; after replacing the water-based polyurethane resin with a water-based acrylic resin in the white water-based ink for scraping in Comparative Example 2, the scratch resistance and rollability of the scraping area of the immediate lottery ticket are poor. After crushing the ink layer due to poor rollability, there are solid powder of the ink on the hands, making them dirty. It can be seen that the combination of the water-based resin in the black water-based ink for scraping and the water-based polyurethane resin in the white water-based ink for scraping selected in the present invention can not only solve the problem of poor aging scraping performance of the scraping area of the immediate lottery ticket, but also solve the problems of poor scratch resistance, rollability, and easy dirtiness of the scraping area of the immediate lottery ticket.

[0172] From the above experimental results, it can be seen that the flexographic water-based scraping ink of the present invention has the following beneficial effects:

[0173] 1. Printing a combination of two layers of high-color-concentration black water-based ink for scraping and two layers of high-opacity white ink for scraping above the UV isolation oil makes the data information on the immediate lottery ticket unreadable under strong light irradiation, ensuring the security of the immediate lottery ticket.

[0174] 2. The high-opacity white water-based ink for scraping on the immediate lottery ticket has good opacity, ensuring good visual appearance on the front of the immediate lottery ticket.

[0175] 3. The combination of the water-based resin in the black water-based ink for scraping and the film-forming resin in the white water-based ink for scraping balances the scraping performance and packaging scratch resistance of the immediate lottery ticket. The scraping value of the immediate lottery ticket tested with an electric scraping instrument is 350-450 g / 5B. It provides excellent scraping performance for the coating in the scraping area, enabling the ink layer in the scraping area of the immediate lottery ticket to be easily scraped off.

[0176] 4. The instant scratch-off flexographic water-based ink can achieve high-speed printing with an instant scratch-off ticket printing speed of 300 m / min, and the printing suitability of the ink is excellent.

[0177] 5. The ink layer in the scratch-off area is easy to scratch off, has good winding properties, and does not dirty hands when twisted by hand. The scratch-off process is smooth and relieves pressure, greatly improving the scratch-off experience of lottery buyers.

[0178] 6. The ink layer in the scratch-off area has good winding properties, and the scratch-off area is in a roll strip shape, preventing the solid powder of the ink layer from flying around, ensuring the cleanliness of the sales site, 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, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

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

2. The flexographic water-based scratch-off ink according to claim 1, characterized in that: The black water-based ink comprises the following components by weight: 35-45 parts of water-based resin; Pigment 35-43 parts; Wetting agent 2.5-3 parts; Defoaming agent 0.5-1.5 parts; 1-1.2 parts of slip aid; 15-17.8 parts of deionized water; And / or, the scraped white water-based ink comprises the following components in parts by weight: 35-45 parts of titanium dioxide; Styrene acrylic emulsion 10-15 parts; 20-28 parts of waterborne polyurethane resin; Dispersant 2.5-3 parts; Wetting agent 2.5-3 parts; 1.5-3 parts of defoaming agent; 3-4 parts of slip agent; 10.5-14.5 parts of 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 35-50wt%, preferably 35-45wt%, more preferably 40wt%; the content of the pigment is 35-50wt%, preferably 35-43wt%, more preferably 38wt%; and / or, In the scraped white water-based ink, the sum of the contents of the styrene acrylic emulsion and the water-based polyurethane resin is 20-45wt% of the water-based resin, preferably 30-43wt%, and more preferably 38wt%.

4. The flexographic water-based scratch-off ink according to any one of claims 1 to 3, characterized in that: The mass ratio of the waterborne polyurethane resin, the styrene acrylic resin and the waterborne acrylic resin is (5-7):(18-23):(10-15).

5. The flexographic water-based scratch-off ink according to any one of claims 1 to 4, 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 siloxane copolymer emulsion; and / or, The slip aid is a water-based silicone emulsion; and / or, The titanium dioxide is rutile titanium dioxide; and / or, The dispersant is a high molecular weight block copolymer.

6. The flexographic water-based scratch-off ink according to any one of claims 1 to 4, characterized in that: The pigment is selected from one or more of carbon black, iron black, and aniline black; preferably, the pigment is a water-based black slurry; and / or, The wetting agent is selected from one or more of TEGO Wet 280, TEGO Wet 270 or BYK-333; and / or, The defoaming agent is selected from one or more of TEGO845, Tego Airex 902W or TEGO Foamex1488; and / or, The slip aid is selected from one or both of DOWSIL 51 Additive and DOWSIL 8526 Additive; and / or, The dispersant is selected from one or both of Korean KS Rheorlow DS-361 dispersant and TEGO Dispers 760W.

7. The flexographic water-based scratch-off ink according to any one of claims 1 to 4, characterized in that: The pigment is a water-based black slurry; the wetting agent is TEGO Wet 280; the defoaming agent is TEGO845; the slip agent is DOWSIL8526Additive; the titanium dioxide is rutile titanium dioxide; and the dispersant is KS Rheorlow DS-361.

8. The method for preparing the flexographic water-based scratch-off ink according to any one of claims 1 to 7, characterized in that: include: 1) preparing the scrape-off black water-based ink and the scrape-off white water-based ink respectively; 2) Overprint two layers of black water-based scratch-off ink on the UV isolation oil, and then overprint two layers of white water-based scratch-off ink on the black scratch-off ink to make flexographic water-based scratch-off ink.

9. The method for preparing the flexographic water-based scratch-off ink according to claim 8, characterized in that: The method for preparing the scraped black water-based ink comprises the following steps: firstly mixing a water-based resin, a pigment, a defoamer and deionized water, grinding and stirring at a speed of 1000-1500 r / min, and grinding and stirring for 90-120 min to obtain a mixed dispersion ①; secondly mixing the mixed dispersion ①, a wetting agent and a slip agent, stirring at a speed of 1000-1500 r / min, and stirring for 30-40 min to obtain the scraped black water-based ink; The method for preparing the scraped white water-based ink comprises the following steps: firstly mixing deionized water, styrene acrylic emulsion, titanium dioxide, dispersant and defoamer, grinding and stirring at a speed of 1500-2000 r / min, grinding and stirring for 120-180 min, to obtain a mixed dispersion ②; secondly mixing the mixed dispersion ②, water-based polyurethane resin, wetting agent and slip agent, stirring at a speed of 1000-1500 r / min, stirring for 60-90 min, to obtain the scraped white water-based ink.

10. Use of the flexographic water-based scratch-off ink according to any one of claims 1 to 7 in preparing and printing instant tickets or invoices that need to be scratched off for prize redemption; preferably, the instant ticket is a welfare instant ticket or a sports instant ticket.

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